記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： https://doi.org/10.1007/s10265-024-01587-4

担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s10265-024-01587-4

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Leguminous green manure plants play an important role in increasing agricultural crop production in infertile soils as they can improve soil quality with less environmental concerns. Many studies have reported suitable green manure plants for temperate regions, but little information is available for tropical regions. Therefore, we clarified the growth response of three common tropical leguminous green manure plants, i.e., cowpea (Vigna unguiculata), sunn hemp (Crotalaria juncea), and green gram (Vigna radiata), on a Haplic Acrisol, which is strongly acidic and low in available phosphate (P) and widespread in Southeast Asia, in comparison with the other P deficient soil, a Eutric Gleysol, which is a slightly acidic and P deficient soil typically found in alluvial area, with controlling soil pH and soil available P. Cowpea was able to yield the highest dry matter production and acquire the largest amount of P among the three green manure plants in the two soils. The amount of P acquired by cowpea from the Gleysol is 6-7 times greater than that from the Acrisol. However, it was also clarified that the P acquiring ability of cowpea would be insufficient even when the Acrisol was ameliorated with CaCO3 and P fertilizers as the Gleysol. Therefore, it would be necessary to find other green manure species which have higher P acquisition abilities enough to give suitable growth on Acrisols.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Soil organic matter (SOM) is one of the largest carbon (C) reservoirs on Earth, and therefore its stability attracts a great deal of interest from the perspective of the global C cycle. This study examined the applicability of loss-onignition with a stepwise increase in temperature (SIT-LOI) of soil to evaluate the stability of SOM using soil samples having different organic matter (OM) and mineral contents and different mean residence times (MRTs) for SOM. The responses of SOM to the SIT-LOI varied depending on the samples but were all successfully approximated by a liner regression model as a function of the temperature of LOI. The slope value in the liner model that determines the residual potential of carbon during the SIT-LOI highly correlated with MRT of SOM, suggesting that this value reflects the overall stability of SOM over a range of soil properties. This hypothesis was consistent with the observation that Δ14C values of SOM decreased with increasing LOI temperature and thus, older, slower-cycling SOM was preferentially left in the soil samples by SIT-LOI. Additionally, the hypothesis was
also supported by the significant correlations (p < 0.01) between the slope value and OM and mineral contents in the samples because these components are considered to regulate SOM stability. In addition to the regression analysis of the SIT-LOI data, changes in carbon to nitrogen (C/N) and carbon to hydrogen (C/H) ratios and stable carbon isotope signatures (δ13C) of the samples were investigated. The results suggest that the mineral association of SOM is an important factor characterizing the response of SOM to LOI. Hence, it was concluded that SITLOI is a simple and useful method for evaluating the stability of SOM under actual environmental conditions.

DOI： 10.1016/j.envres.2023.117224

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In recent years, computer simulation has been increasingly used to predict changes in actual ecosystems. In these studies, snapshots of ecosystems at certain points in time were instantly constructed without considering their evolutionary histories. However, it may not be possible to correctly predict future events unless their evolutionary processes are considered. In this study, we developed a new ecosystem model for reproducing the evolutionary process on an oceanic island, targeting Nakoudojima Island of the Ogasawara Islands. This model successfully reproduced the primitive ecosystem (the entire island covered with forest) prior to the invasion of alien species. Also, by adding multiple alien species to this ecosystem, we were able to reproduce temporal changes in the ecosystem of Nakoudojima Island after invasion of alien species. Then, we performed simulations in which feral goats were eradicated, as had actually been done on the island; these suggested that after the eradication of feral goats, forests were unlikely to be restored. In the ecosystems in which forests were not restored, arboreous plants with a high growth rate colonized during the early stage of evolution. As arboreous plants with a high growth rate consume a large amount of nutrient in soil, creating an oligotrophic state. As a result, plants cannot grow, and animal species that rely on plants cannot maintain their biomass. Consequently, many animals and plants become extinct as they cannot endure disturbances by alien species, and the ecosystem loses its resilience. Therefore, even if feral goats are eradicated, forests are not restored. Thus, the founder effect from the distant past influences future ecosystem changes. Our findings show that it is useful to consider the evolutionary process of an ecosystem in predicting its future events.

DOI： 10.1038/s41598-023-42529-9

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Disturbances caused by invasive ungulates alter soil environments markedly and can prevent ecosystem recovery even after eradication of the ungulates. On oceanic islands, overgrazing and trampling by feral goats has caused vegetation degradation and soil erosion, which can alter soil chemistry. To understand the effects of the changes on plant performance, we conducted a laboratory experiment to assess herbaceous species growth under various soil conditions with phosphorous, nutrients, and acidity. Subsoil was collected from Nakodo-jima in the northwest Pacific. Six herbaceous species dominating the island were grown in soils with three levels of added CaCO₃ and P₂O₅ and two levels of added KNO₃. After 4 weeks of growth, the total dry plant weight was significantly lower with no added P₂O₅, regardless of the addition of KNO₃. Three species weighed more under P₂O₅ and KNO₃ addition in high-pH soil, whereas the remaining three weighed less. Our results indicated that herbaceous species growth is limited primarily by phosphorous availability; the limitation is dependent on soil pH, and the trend of dependency differs among species. This implies that ecosystems with extreme disturbances cannot recover without improving the soil chemistry.

DOI： 10.1038/s41598-023-38934-9

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

第28 回ペドロジスト・トレーニングコースで調査した九州大学農学部附属演習林の福岡演習林における4 地点（ペドン1 ～ 4）の土壌について，土壌断面調査，理化学性分析，および鉱物分析を行い，土壌分類と土壌生成過程の検討を行った。同一の堆積岩地帯に位置するペドン1 ～ 3 の土壌は，いずれも酸性が強く，CEC が高く，主要な粘土鉱物として1.8 nm まで膨潤するスメクタイトを含んでいたが，これらの特性は母岩である堆積岩（腐朽礫）の特性を直接引き継いだものであり，土壌生成作用を受けた結果生じたものではないと考えられた。日本土壌分類体系（2017）に基づく土壌分類は，ペドン1 はリン酸吸収係数の高さから“ばん土質褐色森林土”，ペドン2 は表面水湿性特徴をもつことから“普通疑似グライ土”に分類された。ペドン3 はリン酸吸収係数が15 g P2O5 kg-1 以上の層位が土壌表面から50 cm 以内に積算して厚さ25 cm あり“普通非アロフェン質黒ボク土”に分類されたが，火山放出物含量が少ないことおよび土壌生成作用を強く受けていないことから，ペドン3 はペドン1 と同じく“褐色森林土大群”に分類されるのが妥当と考えられた。ペドン4 は，蛇紋岩と苦鉄質片岩が混在する地域上に位置しており，土壌は弱酸性であり，粘土鉱物として蛇紋石を含んでいたことから，現地性の岩石を主な母材として形成されたと考えられた。ペドン４は，土壌層位の分化が発達途上にありＢ層を欠くことから，“普通固結岩屑土”に分類された。

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

山口県美祢市に位置する日本最大級の石灰岩カルスト台地である秋吉台の剣山山頂付近の土壌について断面形態，理化学特性ならびに土壌分類について検討した。層序は，A 層，Bw 層およびBt 層から構成されており，石礫はほとんど認められなかった。全層を通じて強酸性を呈し，低い塩基飽和度を示したが，下層でわずかに上昇する傾向が認められた。また，Bt2 層では交換性陽イオン（Ca + Mg + K + Na）の総量が交換性アルミニウム（Al）含量を上回り，下層での富塩基性が示された。A2 層は，活性Al 反応が+（即時呈色するがその程度は弱い）であり，リン酸吸収係数やAlo+1/2 Feo の値からも黒ボク特徴は満たさない。しかし，A2 層の活性Al 反応の結果およびリン酸吸収係数やAlo+1/2Feo の値は上下の層位よりも高い値を示したことから，火山噴出物の混入が推察された。また，粒径組成は表層のシルト含量が相対的に高いため，表層付近での広域風成塵の混入が示唆された。併せて，Bt 層では粘土含量の急激な増大が認められたことから，粘土の下方への移動・集積も生じていると考えられた。これらのことから，秋吉台の土壌は火山噴出物や広域風成塵の混入を受けつつ，石灰岩の比較的強い風化や溶脱の影響下で生成するものと考えられた。土壌分類は，日本土壌分類体系ならびに包括的土壌分類第１次試案ではいずれも赤色粘土集積赤黄色土にキーアウトされ，石灰岩の影響は反映されなかった。また，World reference base for soil resources 4th edition（WRB, 2022）ではChromic Luvisols (Clayic, Cutanic, Differentic, Epidystric) に分類された。これは，WRB（2022）では50 cm 以深における交換性Al 含量と交換性陽イオン（Ca + Mg + K + Na）の総量との比較を重視するためであった。ただし，剣山の土壌はBw 層が発達し，Bt 層ではやや富塩基性を示したものの地中海沿岸の石灰岩上に分布する赤褐色土（いわゆるテラロッサ）と比べて断面全体を通して低いpH ならびに交換性陽イオン含量を示した。

記述言語：英語   掲載種別：研究論文（学術雑誌）  

多くの種が生育する半自然草地の復元には、種子の供給源だけでなく、それらの生育に適した土壌環境も必要である。ヨーロッパでは、施肥の履歴のがある草原の土壌が適切な状態になり、草原再生に成功したとみなされるまでに約10年かかるとされている。一方、日本では降水量が多いために塩基性陽イオンが土壌から溶脱し酸性化することや、火山噴出物がリン酸の吸着力の高いアルミニウムや鉄の水酸化物を形成することから、土壌環境の改善にはさらに時間がかかる可能性がある。このような背景のもと、本研究では、i) 日本における半自然草原への半世紀前の施肥の影響がどのように残っているか、ii) 日本における半自然草原の再生に施肥がどのように影響するか、という疑問に答えることを目的とした。半世紀前に1回の施肥が行われたシバが優占する放牧地（改良放牧地）と、そこに隣接する施肥や播種履歴のない半自然草原（在来放牧地）の植生と土壌特性を調査し、次のことが明らかになった。(1) 2つの放牧地のシバの優占度はほぼ同じであったが、種構成は異なっていた。(2) 改良放牧地は在来放牧地よりも種数が少なかった。(3) 窒素、リン、カリウム、マグネシウム、カルシウムなどの土壌化学性は、改良放牧地の方が在来放牧地より高かった。(4) 分析した多くの土壌化学特性の項目は種構成と関係しており、すなわち富栄養な場所では土壌に生育する外来種の種数は増え、在来種の種数は減少していた。これらのことから、過去の1回の施肥が半世紀以上にわたって日本の半自然草原の土壌特性に影響を与え、種の消失や種組成の変化につながることが示唆された。日本の放牧地において施肥をした場合、多くの種が生育する半自然草原の再生に適した土壌環境に回復するのに半世紀以上必要である可能性が示唆された。（横川によるAbstractの和訳）

DOI： 10.1371/journal.pone.0275808

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Properties and classification of paddy soils located on the lowlands of northern and central areas of Mie prefecture, Japan

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Abstract

Selective removal of lignin and other recalcitrant compounds, collectively registered as acid-unhyrolyzable residue (AUR), results in bleaching of leaf litter, but the importance of bleaching in decomposition processes on forest soil has not been fully evaluated. The aims of this study were to elucidate the occurrence of bleached area in decomposing leaf litter and to compare chemical composition between bleached and nonbleached portions in a subtropical forest in Japan. Field incubation of leaf litter was performed over an 18-month period with the litterbag method. The decomposition processes during the first 9 month were characterized by the relatively rapid mass loss and increase of bleached area, whereas the mass loss was slowed down and the bleached area decreased thereafter. Mass loss of leaf tissues was faster and AUR content was lower in bleached than in nonbleached portions, indicating the acceleration of mass loss in bleached leaf tissues by the selective decomposition of recalcitrant compounds. The decrease in carbonyl-C in the bleached portions was associated with the increase of extractable nitrogen. The results suggest that the bleaching plays a dominant role in the transformation and turnover of organic compounds and nitrogen in decomposing leaf litter.

DOI： 10.1038/s41598-021-81206-7

記述言語：英語   掲載種別：研究論文（学術雑誌）  

半自然草原として維持されてきた草地が、約50前に人工改良草地として施肥管理が施されるようになった結果、土壌に施用されたカルシウムとマグネシウムは交換性イオンとして地下1mにまで達していること、もともと強酸性だった土壌は下層土まで弱酸性化されており酸性障害は起こらないレベルまで中和されていること、土壌中でほとんど動かないと考えられているリン酸も80～100cmまで到達していることが明らかになった。このような施肥管理が今後も続けば、施用した成分はいずれ地下水や周辺環境を汚染することが懸念される。

DOI： 10.1080/00380768.2021.1887711

記述言語：その他   掲載種別：研究論文（学術雑誌）  

Leaf ionome indicates plant phylogenetic evolution and responses to environmental stress, which is a critical influential factor to the structure of species populations in local edaphic sites. However, little is known about leaf ionomic responses of local plant species to natural edaphic mineral variations. In the present study, all plant species and soil samples from a total of 80 soil sites in Shiozuka Highland were collected for multi-elemental analysis. Ioniomic data of species were used for statistical analysis, representing 24 species and 10 families. Specific preferences to ionomic accumulation in plants were obviously affected by the phylogeny, whereas edaphic impacts were also strong but limited within the phylogenetic preset. Correlations among elements resulted from not only elemental synergy and competition but also the adaptive evolution to withstand environmental stresses. Furthermore, ionomic differences of plant families were mainly derived from non-essential elements. The majority of variations in leaf ionome is undoubtedly regulated by evolutionary factors, but externalities, especially environmental stresses also have an important regulating function for landscape formation, determining that the contributions of each factor to ionomic variations of plant species for adaptation to environmental stress provides a new insight for further research on ionomic responses of ecological speciation to environmental perturbations and their corresponding adaptive evolutions.

DOI： 10.3389/fpls.2021.614613

その他リンク： https://doi.org/10.3389/fpls.2021.614613

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）  

記述言語：日本語  

2022年から実施される学習指導要領の改訂では，地理歴史科の科目が「地理総合」，「地理探求」に変更となり，地図や地理情報システムの活用による国際性，主体的な思考力の養成が求められることとなった。これにあわせて，土壌に関して国内外で蓄積されてきた研究成果を基礎にした，正確な地図および用語を高校生が活用できるように，高校地理の土壌に関わる教育内容の更新が喫緊の課題である。そこで，現行の高校地理（地理Ｂ）の教科書にみられる用語および地図の問題点を整理し，教育内容の修正・更新案を提示した。具体的には，(1)チェルノーゼム，プレーリー土，パンパ土，栗色土の統一，(2)単独の土壌分類名と対応しないツンドラ土の削除，(3)「ラテライト」の削除とフェラルソル（ラトソル）への統一，(4)ポドゾル，フェラルソルの分布域の過大評価の修正，(5)テラロッサ，テラローシャを含む「粘土集積土壌」の追加，(6)間帯土壌（成帯内性土壌）として黒ボク土，沖積土の追加である。これによって，世界の土壌の分布と生業や文化との関わり，日本の主要な土壌の地理的分布とその特異性の理解促進に貢献できる。

DOI： 10.18920/pedologist.63.2_73

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Ecosystem changes following the eradication of invasive species: evaluation of various eradication scenarios by computer simulation
The decline of the natural ecosystem on the Ogasawara Islands caused by invasive species has been an important environmental problem and projects for eradicating invasive species are currently underway. Some invasive species have proliferated in the host environment and are affecting the material cycle in the ecosystem. If the invasive species were removed from the environment, the material cycle of the ecosystem may be altered and native species that should be protected may be negatively affected. After the introduction of invasive alien species, namely goats and rats, the vegetation declined on Nakoudojima Island, an island that belongs to the Ogasawara Islands. Therefore, in this study, a mathematical model was developed to simulate and analyze the ecosystem changes that occurred following the eradication of goats and rats. When only rats were eradicated, the island's vegetation changed to grassland but revegetation was delayed and the biomass of the native animal species did not recover significantly. When only goats were eradicated, the vegetation recovered and the biomass of the native animal species increased; however, the island became forested and many native herbaceous plant species became extinct. When goats and rats were eradicated simultaneously, the vegetation recovered and the biomass of the native animal species increased; however, the ecosystem became very unstable and two extreme results were obtained - the vegetation of the entire island changed to either forest or grassland. The results of this study suggest that instead of simply eradicating invasive species, it is necessary to monitor post-eradication changes in the ecosystem and take adaptive measures as required.

DOI： 10.1016/j.ecolmodel.2019.108831

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Soil erosion after vegetation degradation induced by disturbance by feral goats, an invasive mammal, can lead to loss or accumulation of soil at a local scale and can alter soil chemical properties. This alteration of soil properties can in turn affect the establishment of plant species. We evaluated relationships among the extent of soil erosion, soil chemical properties, and the distribution of plant species in grassland ecosystems after goat eradication on Nakodo-jima Island in the northwestern Pacific. In 105 1 x 1-m quadrats, changes were measured in the position of topsoil over 2 years. Surface soils were sampled for analysis of chemical properties, and plant species in the quadrat were recorded. Changes in the position of topsoil were related to the area of bare ground. Soil loss occurred at sites where areas of bare ground were extremely large. Significantly higher values of soil exchange acidity and smaller amounts of available phosphorus, total carbon, and total nitrogen were detected in soils at sites with large soil losses. Most of the 11 dominant plant species were absent from sites with large losses of soil. The presence of eight species was significantly negatively related to soil exchange acidity, and three species were significantly positively related to available phosphorus. Our results indicated that exposure of subsoils at the soil surface after vegetation degradation can increase soil loss, which can alter soil chemical properties, and this alteration can continue to limit the establishment of plant species, even long after goat eradication.

DOI： 10.1111/rec.12854

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Soil organic phosphorus (P) is an important P source for biota especially in P-limited forests. Organic P has various chemical formations which differ in bioavailability and these organic P can be degraded by phosphatase enzymes. Here, we report soil P fractions inferred from solution 31P-NMR spectroscopy and soil phosphatase activities of two tropical rain forests on contrasting parent materials
sedimentary and ultramafic igneous (serpentinite) rocks. Compared to the sedimentary soils and previous studies, P fractions of the serpentinite soils have distinctly high proportions of pyrophosphate and scyllo-inositol hexakisphosphate (scyllo-IP6). The accumulation of pyrophosphate and scyllo-IP6 may be related to strong sorptive capacity of iron oxides present in the serpentinite soils, which implies a consequent low P availability in the serpentinite soils. Mean value of soil phosphatase activities was higher in the serpentinite soils than in the sedimentary soils, suggesting that biota in these serpentinite forests depend more on soil organic P as a P source.

DOI： 10.1080/00380768.2017.1421018

記述言語：その他  

Methylobamine, a UVA-Absorbing Compound from the Plant-Associated Bacteria Methylobacterium sp.

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1080/13416979.2017.1326656

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Effective conservation of global species diversity requires a clear understanding of spatial scales that support overall diversity across broad scales. Abandonment of semi-natural grasslands has increased their fragmentation and decreased their areal extent. We quantified diversity patterns of plant communities in Japan across hierarchical scales to facilitate the development of an effective nationwide strategy for conserving species diversity in remnant semi-natural grasslands. We applied additive partitioning of plant species diversity, using a nested hierarchical design at three spatial scales (quadrat, grassland, and western and eastern regions of Japan) for three groups of plant species (all species, grassland species and national Red Listed species). We consistently found lower proportions of among-quadrats diversity, and higher proportions of among-grasslands diversity and between-regions diversity in the overall diversity of the entire species complement than would be expected by chance. The high contribution of among-grasslands diversity to overall diversity suggests that each grassland had a unique species content. The second-ranking contributor to overall diversity differed between grassland species and Red Listed species: the second-ranking contributor for grassland species was diversity at the among-quadrats scale but the second-ranking contributor for all species and for Red Listed species was diversity at the between-regions scale. Thus, effective conservation of diversity of the entire species complement in remnant semi-natural grasslands requires preservation of beta diversity in individual grasslands. Our findings highlight the importance of strengthening local preservation and restoration activities within each grassland, and of nationwide strategies for conserving Red Listed species in remnant semi-natural grassland communities.

DOI： 10.1017/S0030605316001526

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Microbes inhabiting the phyllosphere encounter harmful ultraviolet rays, and must develop adaptive strategies against this irradiation. In this study, we screened bacterial isolates originating from the phyllosphere of various plants which harbored absorbers of ultraviolet A (UVA), a wavelength range which is recognized as harmful to human skin. Of the 200 phyllosphere bacterial isolates we screened, methanol extracts from bacterial cells of seventeen isolates absorbed wavelengths in the range of 315-400 nm. All of the UVA-absorbing strains belonged to Methylobacterium species based on 16S ribosomal RNA gene sequences, suggesting that cells of this bacterial genus contain specific UVA-absorbing compounds. When cells of a representative Methylobacterium strain were extracted using various solvents, UVA absorption was observed in the extracts obtained using several aqueous solvents, indicating that the UVA-absorbing compounds were highly polar. A compound was purified using solid columns and HPLC separation, and comparative analysis revealed that the absorption strength and spectrum of the compound were similar to those of the known UVA filter, avobenzone. The compound was also verified to be stable under UVA exposure for at least 480 min. Based on these results, the UVA-absorbing compound harbored by Methylobacterium has potential to be used as a novel sunscreen ingredient. (C) 2016 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jphotobiol.2016.12.019

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Tricholoma matsutake, a basidiomycete, forms ectomycorrhizas with Pinus densiflora as the host tree. Its fruiting body, matsutake in Japanese, is an edible and highly prized mushroom, and it grows in a circle called a fairy ring. Beneath the fairy ring of T. matsutake, a whitish mycelium-soil aggregated zone, called shiro in Japanese, develops. The front of the shiro, an active mycorrhizal zone, functions to gather nutrients from the soil and roots to nourish the fairy ring. Bacteria and sporulating fungi decrease from the shiro front, whereas they increase inside and outside the shiro front. Ohara demonstrated that the shiro front exhibited antimicrobial activity, but the antimicrobial substance has remained unidentified for 50years. We have identified the antimicrobial substance as the (oxalato)aluminate complex, known as a reaction product of oxalic acid and aluminum phosphate to release soluble phosphorus. The complex protects the shiro from micro-organisms, and contributes to its development.

DOI： 10.1080/09168451.2016.1238298

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A hydrolyzable tannin, oenothein B, has recently been identified as a novel type of Al-binding and detoxifying ligand in a highly aluminum (Al)-resistant tree, Eucalyptus camaldulensis. Oenothein B is mainly localized in the root symplast, where the known ligands, citrate and oxalate, are also present. In this study, to investigate whether oenothein B can form complexes with Al in the presence of citrate and oxalate, we analyzed the chemical form of Al in multiple-ligand mixtures containing Al, oenothein B, citrate, and oxalate in vitro at concentrations mimicking those in the symplast of E. camaldulensis roots. In the mixture, 27% of total Al was detected in the insoluble fraction, and 28% in the high-molecular mass (> 10 kDa) soluble fraction. This means that more than half of Al in the mixture interacts with oenothein B, because among the three ligands only oenothein B can predominantly form insoluble or high molecular mass soluble complexes with Al. The²⁷Al-nuclear magnetic resonance analyses of the mixture showed that low-molecular mass soluble Al was not mainly composed of simple Al–citrate or Al–oxalate complexes. These results support our hypothesis that oenothein B contributes to internal detoxification of Al in the symplast of E. camaldulensis roots.

DOI： 10.1080/13416979.2017.1326656

記述言語：日本語  

記述言語：日本語  

土壌の物質循環機能を多角的にみる―最先端手法が切り拓く新たな姿

DOI： 10.20710/dojo.87.4_283

記述言語：日本語  

Volcano-originated services for agriculture

記述言語：日本語  

DOI： 10.18920/pedologist.60.1_46

記述言語：その他   掲載種別：研究論文（学術雑誌）  

Environmental contextRice is a major human dietary source of arsenic. We identified a novel organoarsenic species, arsinothricin, produced by a bacterium in the rice rhizosphere. This result suggests diverse biochemical dynamics and microbial biodiversity of arsenic metabolism in the rice rhizosphere. AbstractMethylated arsenic compounds in rice grains originate from the action of soil bacteria in the rice rhizosphere. Here, we investigated the chemical structures of arsenic compounds produced by a bacterium, Burkholderia gladioli strain GSRB05, in the rice rhizosphere. When cultured in liquid R2A medium containing arsenite (AsIII), strain GSRB05 produced two unknown novel arsenic compounds that were later identified as arsinothricin (AST, 2-amino-4-(hydroxymethylarsinoyl)butanoic acid), an arsenic mimetic of the herbicide phosphinothricin, and a probable hydroxyl precursor of AST, termed AST-OH (2-amino-4-(dihydroxyarsonoyl)butanoic acid). The chemical structure of AST was determined by means of liquid chromatography–high-resolution tandem mass spectrometry and NMR analyses, whereas that of AST-OH was estimated by means of ultra-high-performance liquid chromatography–tandem mass spectrometry. Time-dependent AsIII transformation by strain GSRB05 showed that AST was produced after AST-OH. Compared with AsIII, AST showed higher absorption by, and was more toxic to, Escherichia coli DH5α cells in M9 minimal medium, which lacks amino acids. These findings have implications for the environmental transfer of arsenic, and human health consequences in terms of our dietary burden of arsenic.

DOI： 10.1071/en14247

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Soil water repellency (SWR) of soils is a property with significant consequences for agricultural water management, water infiltration, contaminant transport, and for soil erosion. It is caused by the presence of hydrophobic agents on mineral grain surfaces. Soils were samples in different depths at three forest sites in Japan and three pasture sites in New Zealand, covering soil organic carbon (SOC) contents between 1 and 26&#37;. The SWR was measured over a range of water contents by three common methods; the water drop penetration time (WDPT) test, the molarity of an ethanol droplet (MED) method, and the sessile drop method (SDM). The aim to (i) compare the methods, (ii) characterize the soil-water repellency characteristic curves (SWRCC) being SWR as a function of the volumetric soil-water content (theta) or matric potential (psi), and (iii) find relationships between SWRCC parameters and SOC content. The WDPT, MED, and SDM generally agreed well in predicting the theta Orange where SWR occurred, and there was close agreement between SWR results determined by average MED and SDM at similar theta. Generally, SWR was only found within the top 20 cm of the soil profiles. Six SWR parameters were introduced: (i) the area under the curve (S-WR(theta)); (ii) theta at the maximum SWR (theta(WR-max)), (iii) theta where SWR ceased (theta(non-WR)), (iv) the maximum SWR (CA(i-max)) (v) pF at the maximum SWR (pF(WR-max)) and (vi) pF where SWR ceased (pF(non-WR)) The relationship between the first three parameters and SOC content were best described with Langmuir type equations (r(2) of 0.5-0.7), while the other three parameters changed linearly with SOC contents. (C) 2015 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.geoderma.2015.10.020

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Thermochemical conversion of agricultural wastes to bioenergy has a potential to play forefront roles within the context of the food, energy, and water nexus. The biochar solid product of pyrolysis is a promising tool to manage food crop production and water resources by means of soil amendment. The goal of this study was to understand the fate of surface functional groups and higher-atomic-mass elements during the pyrolysis of pecan shell, which is known to accumulate calcium oxalate. Pecan shell feedstock and biochars were analyzed ex situ using X-ray computed microtomography and solid-state C-13 cross-polarization and magic-angle-spinning NMR spectroscopy; the pyrolysis kinetics was monitored in situ by thermogravimetric analysis gas chromatography (TGA-GC). The NMR spectra indicated the greatest (i) reduction in O/N alkyl functionality and (ii) increase in the aromatic peak between 300 and 500 degrees C. Primary physical transformation was observed near 400 degrees C in the tomography slice images and corresponding attenuation coefficients. Key changes in physical structure (microtomography) as well as chemical constituents (solid-state NMR) of pecan shell at 300-500 degrees C coincided with the evolution of gaseous products (hydrogen, methane, carbon monoxide, carbon dioxide, ethylene, and ethane, as monitored in situ by TGA-GC) occurring at 200-500 degrees C. These observations followed the reported (0 formation and removal of carboxyl surface functional groups of biochar and (ii) conversion of calcium oxalate to carbonate, both occurring at the key transition temperature near 400 degrees C. Combined with the mass balance (99.7&#37;) obtained for gas-, liquid-, and solid-phase products, these findings will facilitate reactor design to optimize syngas and bio-oil yields and manipulate the surface reactivity of biochar soil amendment.

DOI： 10.1021/acs.energyfuels.5b02428

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To conserve indigenous natural ecosystem and help in the recovery of natural vegetation on Nakoudojima Island, which is a subtropical oceanic island in Ogasawara Islands in Japan, we clarified the mechanisms of the changes in soil chemical properties as affected by soil erosion and seabird activities on the island. Under grassland vegetation where influence of feral goat (exotic species) had been severe, the chemical properties of surface soils with a thickness of 5 cm were variable even in a small area of 0.375 km(2); pH(H2O) value range between 4.6 and 6.9, total C content range between 0.36 and 5.62&#37;, total N content range between 0.03 and 0.45&#37;, exchangeable acidity range between 0.5 and 50 mmol(c) kg(-1), and plant-available phosphate (Bray II P) range between 0.4 and 170 mg P2O5 100 g(-1). By clarifying soil profile characteristics under natural and disturbed vegetation and distribution patterns of these soils on the island, the changes in the soil chemical properties were reasonably assigned to the effect of soil erosion caused by feral goats for increased soil exchangeable acidity and decreased soil pH (mainly found in inland area) and to the effect of seabird activities for increased Bray II P and soil exchangeable acidity and decreased soil pH (mainly found in outer rim area with high altitude). It was also clarified that the high soil exchangeable acidity was significantly related to the low productivity of plant biomass for these plots (P<0.01). Soil erosion would have removed surface soils having weak acidity and exposed subsoils having strong acidity to the ground surface, resulting in inhibition of plant growth and delay of vegetation recovery. Based on the findings obtained in the present study, several options were proposed to stop soil erosion and to recover the vegetation, although careful preliminary examination would be necessary for applying them. (C) 2015 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.catena.2015.04.013

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Pyrolysis of waste biomass is a promising technology to produce sterile and renewable organic phosphorus fertilizers. Systematic studies are necessary to understand how different pyrolysis platforms influence the chemical speciation of dissolved (bioavailable) phosphorus. This study employed solution-phase P-31 NMR analyses on slow pyrolysis, fast pyrolysis, and flash carbonization charcoals. Dissolved P speciation of ash-rich (15-62 wt &#37;) biochars produced from manures, sewage sludge, and corn stover were compared with low ash (2-5 wt &#37;) pecan shell biochars. Each biochar was sequentially extracted to investigate the strongly complexed (by NaOH-EDTA; 250 mM NaOH+5 mM EDTA for 16 h) and acid-extractable (by acidic oxalate; 200 mM oxalate at pH 3.5 for 4 h) P fractions. In NaOH-EDTA extracts, P concentration correlated (p < 0.0005) with Zn (r = 0.89), Mn (r = 0.90), and Mg (r = 0.98) concentrations. A strong correlation between orthophosphate and Mg (r = 0.98, p < 0.0005; n = 13) indicated the presence of Mg orthophosphate (and struvite or whitlockite) in all biochars. Only in acidic oxalate extracts, P concentration correlated (p < 0.0005) with Al (r = 0.87) and Fe (r = 0.92) concentrations. Pyrophosphate (P2O74-) persisted (2352&#37; of total P in NaOH-EDTA extracts) in low-ash pecan shell 300-700 degrees C slow pyrolysis biochars. In contrast, ash-rich biochars were primarily (>= 90&#37;) composed of inorganic orthophosphate (PO43-), except 350 degrees C slow pyrolysis swine manure biochar (26&#37; pyrophosphate) and sewage sludge-derived flash carbonization charcoal (14&#37; pyrophosphate). Solid-state C-13 cross-polarization and magic angle spinning NMR analyses of bulk aromaticity indicated partially carbonized (aliphatic) nature of 350 degrees C swine manure biochar. Surface functional groups of swine manure and sewage sludge biochars could stabilize pyrophosphate by (i) utilizing bridging cations (Al-3+, Fe-3+, and Mg-2+) to form stable six-membered ring complexes, and (ii) direct hydrogen bonding.

DOI： 10.1021/acssuschemeng.5b00336

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To evaluate organic carbon (OC) accumulation processes in peat deposits in tropical mangrove ecosystems, solid-state C-13 cross-polarization and magic angle spinning nuclear magnetic resonance signals were measured to determine the DC compositions of decomposed leaves and roots. These account for a large majority of mangrove litters and mangrove peat in a coral reef-type Rhizophora forest on Pohnpei Island, Federated States of Micronesia. Radiocarbon dating was also used to understand the sources of peat deposits at each depth. The mass loss rate of mangrove leaves during 1-year litterbag incubation was much higher than that of roots. These mass loss rates are expected to be affected by the varying chemical characteristics of leaves and roots and the different aerobic/hydrological conditions present in the two litter types during decomposition. The decomposability of individual DC components also varied markedly between leaf and root litters. Significant increases in aryl-C/O-alkyl-C and aliphatic-C/O-alkyl-C ratios and minor increases in the aryl-C/aliphatic-C ratio during leaf decomposition implied that O-alkyl-C was more labile than aryl- and aliphatic-C and that aliphatic-C was also slightly more decomposable than aryl-C, but not significantly so, in leaf litters on the forest floor. Regarding roots, a stable aryl-C/O-alkyl-C ratio during decomposition suggested that aryl- and O-alkyl-C components did not differ greatly in decomposability in the peat deposit, while the minor increase in the aliphatic-/O-alkyl-C ratio and the substantial decrease in the aryl-/aliphatic-C ratio with decomposition implied that aliphatic-C was more recalcitrant than aryl- and O-alkyl-C in the peat. The DC compositional properties were quite homogenous throughout the peat profile, and C-14 dating mostly indicated modern, which suggest that large amounts of mangrove roots penetrate to at least 80 cm depth. These findings provide quantitative and qualitative insights into the potential importance of very high production of mangrove fine roots for DC accumulation in peat in tropical mangrove ecosystems. (C) 2015 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.geoderma.2015.01.008

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Dissolved organic carbon (DOC) components of soil amendments, such as biochar, will influence the fundamental soil chemistry, including the metal speciation, nutrient availability, and microbial activity. Quantitative correlation is necessary between (i) pyrogenic DOC components of varying aromaticity and ionizable (carboxyl and hydroxyl) substituents and (ii) bulk and solution properties of biochars. This study employed fluorescence excitationemission (EEM) spectrophotometry with parallel factor analysis (PARAFAC) to understand the influence of the pyrolysis platform (flash and high-yield carbonization, slow pyrolysis, and fast pyrolysis) and solution pH on the DOC structure of carbonaceous materials. The PARAFAC fingerprint representative of conjugated, polyaromatic DOC correlated (Pearsons r >= 0.6; p < 0.005) with (i) volatile matter content and (ii) total organic carbon and nitrogen concentrations in water and base (50100 mM NaOH) extracts. Electric conductivity of the extracts correlated with S (indicative of labile sulfate species) and Na + K concentrations (r > 0.9; p < 0.0005). The pH-dependent changes in fluorescence peak position and intensity suggested (i) protonation of carboxylate/phenolic functionalities and (ii) acid-induced aggregation of colloidal particles for <= 350 degrees C slow-pyrolysis biochars; DOC of high-yield/flash carbonization charcoals and >= 500 degrees C slow-pyrolysis biochars were less sensitive to pH. Solid-state 13C cross-polarization and magic angle spinning nuclear magnetic resonance analysis of bulk aromaticity (-C-C peak at 110-160 ppm) suggested that both recalcitrant and labile fluorescence DOC fingerprints are composed of polyaromatic structures that begin to form near 350 degrees C. These biochar-borne DOC components of varying aromaticity and carboxyl substituents will participate in hydrophobic and hydrogen-bonding interactions with soil components that will ultimately impact the biogeochemical cycles.

DOI： 10.1021/acs.energyfuels.5b00146

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Emergency Survey for Spatial Mapping of Radioactive Cesium Concentration in Agricultural Soil

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Organic matter (OM) bound to soil mineral particles (higher-density particles) tends to be more stabilized, enriched in C-13 and N-15, and has a lower C:N ratio. Yet how these variations in OM chemistry are linked to the nature of organo-mineral assemblage remains poorly understood, especially in allophanic soils where high amounts of OM are stabilized by interactions with reactive inorganic phases such as short-range-order (SRO) minerals. We thus assessed the extent to which the degree of aggregation and its disruption during fractionation control the distribution and chemistry of the soil organo-mineral particles across six density fractions using a volcanic soil (allophanic Andisol) based on selective dissolution, microscopy (SEM), solid-state C-13 NMR spectroscopy and delta C-13 and delta N-15 analyses. Intermediate-density fractions (2.0-2.5 g cm(-3)) accounted for 63-86&#37; of organic C and N, 73-93&#37; of pyrophosphate-extractable iron and aluminum (Fep, Alp), and 78-95&#37; of oxalate-extractable metals (Feo, Alo) in the bulk soil sample. While air-drying pretreatment had little effect, sonication during fractionation led to (i) fragmentation of both plant detritus and some of the aggregates of 30-100 mm sizes, (ii) release of occluded low-density fraction (<1.6 g cm(-3)) which largely originated from the aggregates of 1.6-2.0 g cm(-3) density range, and (iii) redistribution of organo-mineral particles (15-16&#37; of total OM and 7-19&#37; of the extractable metals) within the intermediate density fractions. Positive correlation of Alp with C:N ratio and negative correlation of Alp with delta N-15 among the fractions suggest preferential binding of Alp phase (e.g., organo-Al complexes) to decaying plant detritus. Positive correlation of Alo and Feo with delta N-15, together with theoretical density calculations of idealistic organo-mineral association modes, suggests that N-15 enrichment may be coupled with OM binding to SRO minerals and with the formation of physically-stable aggregates of micron/submicron sizes in accord with our conceptual model (Asano and Wagai, 2014). The general pattern of C-13 and N-15 enrichment and C:N decline with increasing particle density remained largely unchanged despite the sonication effects detected, indicating that sonication-resistant organo-mineral assemblages largely control the observed patterns. The similarity in the density-dependent changes of OM chemistry between the studied Andisol and the soils with crystalline clay and metal oxide mineralogies in previous studies strongly suggests a common biogeochemical control which deserves further investigation. (C) 2014 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.geoderma.2014.11.028

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The relationship between degradation speed of soil-buried biodegradable polyester film in a farmland and the characteristics of the predominant polyester-degrading soil microorganisms and enzymes were investigated to determine the BP-degrading ability of cultivated soils through characterization of the basal microbial activities and their transition in soils during BP film degradation. Degradation of poly(butylene succinate-co-adipate) (PBSA) film was evaluated in soil samples from different cultivated fields in Japan for 4 weeks. Both the degradation speed of the PBSA film and the esterase activity were found to be correlated with the ratio of colonies that produced clear zone on fungal minimum medium-agarose plate with emulsified PBSA to the total number colonies counted. Time-dependent change in viable counts of the PBSA-degrading fungi and esterase activities were monitored in soils where buried films showed the most and the least degree of degradation. During the degradation of PBSA film, the viable counts of the PBSA-degrading fungi and the esterase activities in soils, which adhered to the PBSA film, increased with time. The soil, where the film was degraded the fastest, recorded large PBSA-degrading fungal population and showed high esterase activity compared with the other soil samples throughout the incubation period. Meanwhile, esterase activity and viable counts of PBSA-degrading fungi were found to be stable in soils without PBSA film. These results suggest that the higher the distribution ratio of native PBSA-degrading fungi in the soil, the faster the film degradation is. This could be due to the rapid accumulation of secreted esterases in these soils.

DOI： 10.1186/s13568-014-0088-x

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

[in Japanese]

DOI： 10.11519/jfsc.126.0_92

記述言語：日本語  

世界の陸地面積に占める火山灰土壌の割合は1&#37;未満であるのに対し，日本の陸地面積に占める割合は少なくとも17&#37;に達する(菅野ら，1999)。とりわけ，日本では農耕地に占める火山灰土壌の割合が高く(畑地の約50&#37;，水田の約20&#37;)，その農作物生産性における問題点やその改良法などが精力的に研究され，多くの成果を挙げてきた。また，日本における火山灰土壌の生成とその分類に関する研究も多くの成果を生み出しているが，これらの成果の中には今後のさらなる議論を経たのちに一般化される必要があるものも少なくないと考えられる。ここでは，火山灰土壌の生成論を中心に得られた知見をレビューし，その中で三瓶山地域における火山灰土壌の生成および特性の位置づけを明らかにしたい。

記述言語：日本語  

記述言語：日本語  

Geology-Ecosystem-Human Activities in Shimane (Agriculture・Iwami Ginzan・Tatara Steel Manufacture) and Soil Formation

記述言語：日本語  

Studies on the behavior of elements in soils by using Nuclear Magnetic Resonance(NMR)(JSSPN Awards)

DOI： 10.20710/dojo.85.5_401

記述言語：英語   掲載種別：研究論文（学術雑誌）  

This study examined the recovery, via biotic and abiotic pathways, of a grassland ecosystem after eradication of introduced exotic goats. We used path analyses to evaluate the relative strength of relationships among aboveground biomass, soil chemical properties (carbon, nitrogen, and phosphorus content; soil acidity), presence of nesting seabirds after goat eradication, extent of vegetation degraded by goats before their eradication, plant species composition after removal of goats, and topography. Models including the same variables with different paths were constructed using the Bayesian estimation method, and the best-fit models were constructed by comparing deviance information criterion values. Results of the path analyses demonstrated that vegetation degradation and soil erosion prior to goat eradication increased soil exchangeable acidity, which resulted in limitation of aboveground biomass. Seabird nesting after goat eradication increased the quantity of soil nutrients, possibly through inputs of feces, eggshells, and dead chicks or adults. The increase in nutrients was affected indirectly, via seabird nesting, by topography and vegetation type after goat eradication. The direct and indirect relationships demonstrated by our results suggest the existence of complex interrelationships during recovery of ecosystem function after eradication of exotic mammals.

DOI： 10.1007/s10021-014-9780-6

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Soil water repellency (SWR) is known to lead to preferential flow and to degrade the soil's filtering efficiency. However, no method is available to quantify directly how SWR affects the transport of reactive solutes. We propose a new method for conducting solute transport experiments in water-repellent soils. It involves sequentially applying two liquids, one water, the other a reference fully wetting liquid, namely aqueous ethanol, to the same intact soil core with air-drying between liquids. We applied this approach to quantify the impact of SWR on the filtering of the herbicide 2,4-Dichlorophenoxyacetic acid (2,4-D) in two Andosols. In batch experiments conducted prior to the transport experiments, 2,4-D sorption was not influenced by aqueous ethanol for one soil. However, sorption in the second soil followed the co-solvency theory, which predicts decreasing sorption with increasing solvent fractions. Thus, sorption experiments are necessary to complement our new method. Breakthrough curves were characterized by preferential flow with large initial concentrations, tailing and a long prevalence of solutes remaining in the soil. In the soil in which 2,4-D sorption was unaffected by aqueous ethanol, SWR increased 2,4-D losses by four and 50 times in the first 5-mm outflow compared with the 2,4-D losses with water. After 50-mm outflow, the 2,4-D losses were similar for one core, but in the other core they were still about four times greater with water than with aqueous ethanol. This method to quantify the reduction of the soil's filtering efficiency by SWR is needed for assessing the increased risk of groundwater contamination by solutes exogenously applied to water-repellent soils.

DOI： 10.1111/ejss.12136

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Aluminum (Al) accumulators are widely distributed in the plant kingdom but phylogenetic implications of internal Al detoxification mechanisms are not well understood. We investigated differences in the characteristics of Al accumulation (i.e., accumulation potential, chemical form, and localization) in three woody Al accumulators, Symplocos chinensis (Lour.) Druce var. leucocarpa (Nakai) Ohwi f. pilosa (Nakai) Ohwi (Symplocaceae, Ericales), Melastoma malabathricum L., and Tibouchina urvilleana Cogn. (both Melastomataceae, Myrtales). The order of Al accumulation potential under hydroponic conditions was S. chinensis approximate to M. malabathricum > T. urvilleana. Oxalate was at least partly involved in the internal Al detoxification mechanisms in leaves of all three Al accumulators, based on a correlation analysis between Al and organic acid in water and 0.02 mol.L-1 HCl extracts and the Al-27 nuclear magnetic resonance spectra of intact leaves. However, the Al forms in the leaves were not simple Al-ligand complexes in a specific cell structure. Al localization in leaf sections differed among the three species. Extremely high levels of Al were found in trichomes of the lower epidermis in leaves of T. urvilleana. These data illustrate that woody Al-accumulating angiosperms have independently developed various internal Al-tolerance mechanisms in which oxalate plays a significant role.

DOI： 10.1139/cjb-2013-0298

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Pyrolysis of plant and animal wastes produces a complex mixture of phosphorus species in amorphous, semicrystalline, and crystalline inorganic phases, organic (char) components, and within organo-mineral complexes. To understand the solubility of different phosphorus species, plant (cottonseed hull) and manure (broiler litter) wastes were pyrolyzed at 350, 500, 650, and 800 degrees C and exposed to increasingly more rigorous extraction procedures: water (16 h), Mehlich 3 (1 mM EDTA at pH 2.5 for 5 mm), oxalate (200 mM oxalate at pH 3.5 for 4 h), NaOH-EDTA (250 mM NaOH + 5 mM EDTA for 16 h), and total by microwave digestion (concentrated HNO3/HCl + 30&#37; H2O2). Relative to the total (microwave digestible) P, the percentage of extractable P increased in the following order: M3 < oxalate approximate to water < NaOH-EDTA for plant biochars and water < M3 < NaOH-EDTA < oxalate for manure biochars. Solution phase P-31 NMR analysis of NaOH-EDTA extracts showed the conversion of phytate to inorganic P by pyrolysis of manure and plant wastes at 350 degrees C. Inorganic orthophosphate (PO43-) became the sole species of >= 500 degrees C manure biochars, whereas pyrophosphate (P2O74-) persisted in plant biochars up to 650 degrees C. These observations suggested the predominance of (i) amorphous (rather than crystalline) calcium phosphate in manure biochars, especially at >= 650 degrees C, and (ii) strongly complexed pyrophosphate in plant biochars (especially at 350-500 degrees C). Correlation (Pearson's) was observed (i) between electric conductivity and ash content of biochars with the amount of inorganic P species and (ii) between total organic carbon and volatile matter contents with the organic P species.

DOI： 10.1021/jf4053385

記述言語：英語   掲載種別：研究論文（学術雑誌）  

At 12,900 a BP, the eruption of the Laacher See volcano generated a new parent material for Holocene soil formation in parts of Western Germany. Weathering of these ashes commonly includes the formation of poorly crystalline minerals such as allophane, imogolite and ferrihydrite. Detection of these minerals in soil is difficult, yet an important task, because they may govern soil functions and processes, e. g., stabilisation of organic matter and nutrient availability. Therefore, we characterised three forested Andosols by a combination of wet-chemical and spectroscopic techniques including infrared and (Al-27, Si-29) nuclear magnetic resonance (NMR) spectroscopy together with X-ray diffractometry. Deconvoluting the Si-29-NMR spectra revealed that 1.6 to 10.4&#37; of total Si was present as allophanic compounds, which coincided with the amounts of oxalate-extractable Si. Since extraction methods are not completely selective, we observed a slight overestimation of allophanic Si estimated from oxalate extraction. Although the sites under study are located close to each other in similar relief positions and with similar vegetation, the combination of our results revealed varying amounts of loess in the parent materials and varying weathering intensity. High weathering intensities correlate with the amounts of allophane. (C) 2013 Elsevier B. V. All rights reserved.

DOI： 10.1016/j.chemgeo.2013.10.029

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To establish a rapid high-throughput evaluation system for the enhanced plant growth-inhibitory activity caused by modifications of cis-cinnamic acid's (cis-CA's) chemical structure, a DNA microarray assay was used to analyze the changes in early gene responses of Arabidopsis thaliana seedlings. After a 6-hr exposure to (Z)-3-(3-iodophenyl)acrylic acid, we observed an upregulation in three classes of early auxin-responsive genes, which was similar to the transcriptional response to indole-3-acetic acid (IAA), together with an upregulation of the genes related to environmental stress and toxin detoxification responses. Gene responses to 2-(3,4-dihydronaphthalen-1-yl)acetic acid were similar to those to IAA. In contrast, fewer genes were upregulated in response to its double-bond isomer, (Z)-2-[3,4-dihydronaphthalen-1(2H)-ylidene]acetic acid, than to cis-CA. DNA microarray data suggest that the structurally different cis-CA analogues trigger diverse gene responses.

DOI： 10.1584/jpestics.D13-090

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We tested whether vegetation recovery on an oceanic island after the eradication of feral goats is related to disturbances by goats and recovery of seabird nesting in an island. To test, we investigated relationships among the aboveground biomass of herbaceous vegetation, nutrient concentrations in the soil after goat eradication, and vegetation degradation before goat eradication and seabird nesting after the eradication. The investigation was conducted on the island of Nakoudojima, a subtropical island situated in the northwestern Pacific Ocean with consideration of fine-scale variation of topography and structure of current vegetation. The aboveground biomass of herbaceous vegetation was correlated with the presence of vegetation degradation before goat eradication but not with seabird nesting after eradication. Concentrations of carbon and nitrogen in the soil were correlated with both the presence of vegetation degradation and seabird nesting. The concentration of available phosphorus in the soil was correlated with nesting seabirds but not with vegetation degradation. The presence of nesting seabirds was correlated with differences in dominant species in the vegetation after goat eradication and with topography. Our results suggested that fine-scale heterogeneities of the aboveground biomass of herbaceous vegetation and the concentrations of nutrients in the soil after goat eradication in an island could be related to vegetation degradation and subsequent erosion of surface soil caused by goats and seabird nesting after the goat eradication.

DOI： 10.1071/PC140344

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Aluminum (Al) accumulators are widely distributed in the plant kingdom but phylogenetic implications of internal Al detoxification mechanisms are not well understood. We investigated differences in the characteristics of Al accumulation (i.e., accumulation potential, chemical form, and localization) in three woody Al accumulators, Symplocos chinensis (Lour.) Druce var. leucocarpa (Nakai) Ohwi f. pilosa (Nakai) Ohwi (Symplocaceae, Ericales), Melastoma malabathricum L., and Tibouchina urvilleana Cogn. (both Melastomataceae, Myrtales). The order of Al accumulation potential under hydroponic conditions was S. chinensis ≈ M. malabathricum > T. urvilleana. Oxalate was at least partly involved in the internal Al detoxification mechanisms in leaves of all three Al accumulators, based on a correlation analysis between Al and organic acid in water and 0.02 mol·L^-1 HCl extracts and the ²⁷Al nuclear magnetic resonance spectra of intact leaves. However, the Al forms in the leaves were not simple Al-ligand complexes in a specific cell structure. Al localization in leaf sections differed among the three species. Extremely high levels of Al were found in trichomes of the lower epidermis in leaves of T. urvilleana. These data illustrate that woody Al-accumulating angiosperms have independently developed various internal Al-tolerance mechanisms in which oxalate plays a significant role.

DOI： 10.1139/cjb-2013-0298

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

野生化ヤギ（ノヤギ）の駆除後、生態系機能の回復過程を評価するために、ノヤギ駆除から約10年経過した媒島の草地生態系において、植生のバイオマス、土壌の化学的特性、ノヤギの駆除前後のイベント（ノヤギ駆除前の植生の退行に伴う裸地化、ノヤギ駆除後の海鳥の営巣）との関係を間接効果も含めて明らかにした。植生の地上部バイオマス、土壌の化学的特性（全炭素量、全窒素量、有効態リン酸量、置換酸度）、ノヤギ駆除前（1991年）における裸地化の有無、海鳥の営巣の有無、という変数聞の各関係とこの関係の相対的な強さを評価した。ノヤギ駆除前の植生の裸地化は、土壌の置換酸度の上昇を介して、植生の地上部バイオマスを減少させる可能性が示唆された。また、ノヤギ駆除後に海鳥の営巣に伴う土壌栄養塩量の増加は、海鳥の営巣と地形や現存植生の種構成との関係に依存することが示唆された。以上からノヤギ駆除後の生態系機能の回復の有無や程度は、複数の生物的、非生物的要因が直接的、間接的によって影響を受けることが示唆された。

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To establish a rapid high-throughput evaluation system for the enhanced plant growth-inhibitory activity caused by modifications of cis-cinnamic acid's (cis-CA's) chemical structure, a DNA microarray assay was used to analyze the changes in early gene responses of Arabidopsis thaliana seedlings. After a 6-hr exposure to (Z)-3-(3-iodophenyl)acrylic acid, we observed an upregulation in three classes of early auxin-responsive genes, which was similar to the transcriptional response to indole-3-acetic acid (IAA), together with an upregulation of the genes related to environmental stress and toxin detoxification responses. Gene responses to 2-(3,4-dihydronaphthalen-1-yl)acetic acid were similar to those to IAA. In contrast, fewer genes were upregulated in response to its double-bond isomer, (Z)-2-[3,4-dihydronaphthalen-1(2H)-ylidene]acetic acid, than to cis-CA. DNA microarray data suggest that the structurally different cis-CA analogues trigger diverse gene responses.

DOI： 10.1584/jpestics.D13-090

記述言語：英語   掲載種別：研究論文（学術雑誌）  

1-O-cis-Cinnamoyl-beta-D-glucopyranose is known to be one of the most potent allelochemical candidates and was isolated from Spiraea thunbergii Sieb by Hiradate et al. (2004), who suggested that it derived its strong inhibitory activity from cis-cinnamic acid, which is crucial for phytotoxicity. In this study, key structural features and substituent effects of cis-cinnamic acid (cis-CA) on lettuce root growth inhibition was investigated. These structure-activity relationship studies indicated the importance of the spatial relationship of the aromatic ring and carboxylic acid moieties. In this context, conformationally constrained cis-CA analogues, in which the aromatic ring and cis-olefin were connected by a carbon bridge, were designed, synthesized, and evaluated as plant growth inhibitors. The results of the present study demonstrated that the inhibitory activities of the five-membered and six-membered bridged compounds were enhanced, up to 0.27 mu M, and were ten times higher than cis-CA, while the potency of the other compounds was reduced. (C) 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.phytochem.2013.10.001

記述言語：英語   掲載種別：研究論文（学術雑誌）  

cis-Cinnamoyl glucosides are the allelochemicals in Thunberg's meadowsweet (Spiraea thunbergii). The essential chemical structure responsible for the bioactivity of cis-cinnamoyl glucosides, cis-cinnamic acid (cis-CA), strongly inhibits the root growth of several plant species; however, its mode of action has not been characterized at the gene expression level. We conducted a time-course microarray analysis of gene expression in Arabidopsis in response to 20 μM cis-CA. Comparison of the microarray profiles revealed a 10-fold upregulation of several auxin-responsive GRETCHEN HAGEN-3 (GH3) genes and LATERAL ORGAN BOUNDARIES DOMAIN/ASYMMETRIC LEAVES2-LIKE (LBD) genes from 2 h to 6 h post-treatment. Two early auxin-responsive gene families, the Aux/IAA family (IAA1, IAA5) and the GH3 family (GH3.1, GH3.2, GH3.3), and an LBD gene (LBD16) were markedly upregulated at 2 h after treatment in the roots, but not in the shoots, of Arabidopsis and remained highly expressed for 4 h. The influence of an exogenous application of cis-CA on the indole-3-acetic acid pathway strongly suggests that a root-targeted induction of auxin-responsive genes is involved in the cis- CA-mediated plant growth inhibition.

DOI： 10.5511/plantbiotechnology.13.0781a

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Eucalyptus (Eucalyptus camaldulensis) has relatively high resistance to aluminum (Al) toxicity than the various herbaceous plants and model plant species. To investigate Al-tolerance mechanism, the metabolism of organic acids and the chemical forms of Al in the target site (root tips) in Eucalyptus was investigated. To do this, 2-year old rooted cuttings of E. camaldulensis were cultivated in half-strength Hoagland solution (pH 4.0) containing Al (0, 0.25, 0.5, 1.0, 2.5 and 5.0 mM) salts for 5 weeks; growth was not affected at concentrations up to 2.5 mM even with Al concentration reaching 6000 mu g g(-1) DW. In roots, the citrate content also increased with increasing Al application. Concurrently, the activities of aconitase and NADP(+)-isocitrate dehydrogenase, which catalyze the decomposition of citrate, decreased. On the other hand, the activity of citrate synthase was not affected at concentrations up to 2.5 mM Al. Al-27-NMR spectroscopic analyses were carried out where it was found that Al-citrate complexes were a major chemical form present in cell sap of root tips. These findings suggested that E. camaldulensis detoxifies Al by forming Al-citrate complexes, and that this is achieved through Al-induced citrate accumulation in root tips via suppression of the citrate decomposition pathway. (C) 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.phytochem.2013.06.016

記述言語：英語   掲載種別：研究論文（学術雑誌）  

1-O-cis-Cinnamoyl-β-d-glucopyranose is one of the most potent allelochemicals that has been isolated from Spiraea thunbergii Sieb by Hiradate et al. It derives its strong inhibitory activity from cis-cinnamic acid (cis-CA), which is crucial for phytotoxicity. By preparing and assaying a series of cis-CA analogues, it was previously found that the key features of cis-CA for lettuce root growth inhibition are a phenyl ring, cis-configuration of the alkene moiety, and carboxylic acid. On the basis of a structure-activity relationship study, the substituent effects on the aromatic ring of cis-CA were examined by systematic synthesis and the lettuce root growth inhibition assay of a series of cis-CA analogues having substituents on the aromatic ring. While ortho- and para-substituted analogues exhibited low potency in most cases, meta-substitution was not critical for potency, and analogues having a hydrophobic and sterically small substituent were more likely to be potent. Finally, several cis-CA analogues were found to be more potent root growth inhibitors than cis-CA.

DOI： 10.1016/j.phytochem.2013.08.013

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

京都議定書における温室効果ガス削減目標が設定されて以来，エネルギー消費への関心が広がるとともに炭素動態に関するデータが蓄積されてきた。我が国で削減目標(90年比6%減)に対する約束期間(2008～2012)内の達成見込みが得られた(2012年12月現在)背景には詳細なデータの積み上げがあった。その膨大なデータには各土地利用における土壌炭素変化量の算出も大きく貢献している。土壌炭素の変化量を算出するためには土壌炭素賦存量が必要であり，そのデータベースの構築と算出法の開発は大きな成果といえる。この成果は，さらに続く排出削減目標に対し，算出法の最適化を図るための基盤になると考えられる。そこで，本シンポジウムでは，国土面積の占有割合が高い森林と農地での土壌炭素賦存量と変化量の算出結果と今後の課題を取り上げた。一方，それら土地利用に含まれない領域として都市域の土壌炭素賦存量算出の問題点も指摘した。さらに，土壌炭素変化量に影響する土壌有機物の分解特性と存在形態に関する話題を挙げた。また，様々な土壌における有機物の多様性を質的データで示し，さらにその変化の方向性についても論及した。土壌炭素に関する量的・質的な取扱いの両面から日本の土壌炭素賦存量について論議を行った。

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Identification of coumarin as the predominant allelochemical in Gliricidia sepium, a leguminous tree of seasonally dry forests.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A crude methanol extract of Gliricidia sepium (Fabaceae) leaves inhibited the growth of lettuce (Lactuca sativa) radicles. To isolate and characterise the inhibitory compound, the extract was fractionated based on the total activity on lettuce radicle elongation. The n-hexane-soluble fraction obtained by liquid-liquid partitioning of the crude methanol extract showed strong inhibitory activity. A compound corresponding to the major peak in high performance liquid chromatography was isolated from the fraction and identified as coumarin. The EC₅₀ of coumarin for the growth of lettuce radicles was 23.3 umol L^-1. On the basis of the coumarin content (11.6 mmol kg^-1 fresh weight) and the total activity of coumarin (500) in G. sepium, we concluded that the inhibitory activity of G. sepium was primarily due to coumarin.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Screening of the growth-inhibitory effects of 168 plant species against lettuce seedlings

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Temperature sensitivity of soil organic matter (SOM) decomposition may have a significant impact on global warming. Enzyme-kinetic hypothesis suggests that decomposition of low-quality substrate (recalcitrant molecular structure) requires higher activation energy and thus has greater temperature sensitivity than that of high-quality, labile substrate. Supporting evidence, however, relies largely on indirect indices of substrate quality. Furthermore, the enzyme-substrate reactions that drive decomposition may be regulated by microbial physiology and/or constrained by protective effects of soil mineral matrix. We thus tested the kinetic hypothesis by directly assessing the carbon molecular structure of low-density fraction (LF) which represents readily accessible, mineral-free SOM pool. Using five mineral soil samples of contrasting SOM concentrations, we conducted 30-days incubations (15, 25, and 35 °C) to measure microbial respiration and quantified easily soluble C as well as microbial biomass C pools before and after the incubations. Carbon structure of LFs (&lt
1.6 and 1.6-1.8 g cm-3) and bulk soil was measured by solid-state 13C-NMR. Decomposition Q10 was significantly correlated with the abundance of aromatic plus alkyl-C relative to O-alkyl-C groups in LFs but not in bulk soil fraction or with the indirect C quality indices based on microbial respiration or biomass. The warming did not significantly change the concentration of biomass C or the three types of soluble C despite two- to three-fold increase in respiration. Thus, enhanced microbial maintenance respiration (reduced C-use efficiency) especially in the soils rich in recalcitrant LF might lead to the apparent equilibrium between SOM solubilization and microbial C uptake. Our results showed physical fractionation coupled with direct assessment of molecular structure as an effective approach and supported the enzyme-kinetic interpretation of widely observed C quality-temperature relationship for short-term decomposition. Factors controlling long-term decomposition Q10 are more complex due to protective effect of mineral matrix and thus remain as a central question. © 2012 Blackwell Publishing Ltd.

DOI： 10.1111/gcb.12112

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Sorghum accumulates sugars (sucrose, glucose and fructose) in the stem after anthesis. Brix is commonly used to indicate total sugar content; however, the relationship between Brix and specific sugar components has not been sufficiently investigated in sorghum juice in Japan. In this study, we measured the sugar components of sorghum juices from 109 varieties using capillary electrophoresis, which can quantify each sugar component in crude juice without further purification. The results indicated that the Brix of sorghum juice was proportional to the total sugar and sucrose concentrations (r=0.900 and r=0.894, P<0.01, respectively). Glucose concentration had a significant positive correlation with fructose concentration (r=0.964, P<0.01), but no correlation was detected between Brix and the two hexose sugars, glucose and fructose. Our results showed that sucrose comprised approximately 75&#37; of the total sugar in varieties with Brix values greater than 15. These findings may be applied in sorghum breeding efforts to develop varieties that accumulate high levels of sugars in the juicy stems of sorghum plants.

DOI： 10.1111/grs.12006

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Questions What is the best way to identify plant indicators for monitoring the responses of semi-natural grassland communities to various management practices (i.e. burning, burning and mowing, burning and grazing)? Can a multi-trait plant functional group (PFG) approach extract indicator species more effectively than a single-trait approach? Location Semi-natural and artificial grasslands in the northern and eastern parts of the somma of Mt. Aso, Kumamoto Prefecture, Japan. Methods We analysed a data set from 203 semi-natural and artificial grassland vegetation plots (each 1 m x 1 m), and compared species and functional compositions among the management types and between the northern and eastern locations using non-metric multidimensional scaling (NMDS). Potential indicator species were extracted by indicator species analysis (INSPAN) and compared with the results of single-trait and multi-trait PFG approaches, which classify plant species into groups based on individual or combinations of traits (growth form, life span, dispersal mode, flowering season and plant height). Results Only the multi-trait PFG approach successfully clustered the vegetation plots for each management type. Semi-natural burned-and-grazed grasslands in the eastern and northern regions were characterized by a specific PFG among 21 PFGs, whereas the same three PFGs characterized the burned-and-mowed semi-natural grassland of the two regions. The extracted PFGs represent combinations of vegetative, dispersal and reproductive traits (e.g. short, wind- and animal-dispersed species for grazed semi-natural grasslands; tall, summer-flowering forbs for mowed semi-natural grasslands). As compared to indicator species extracted by the multi-trait PFG approach, INSPAN extracted additional indicator species, but some of these were inappropriate. Conclusions We identified PFGs representing each management type and characterized species adaptations to different disturbance regimes, such as mowing and grazing. Among the species extracted by INSPAN, only those classified into the representative PFGs can serve as indicators for characterizing managed semi-natural grasslands. Our findings indicate that using a multi-trait PFG approach can provide reasonable plant indicators for monitoring grassland communities throughout the regions when combined with a species-based INSPAN approach. This proposed method would contribute to the conservation of plant biodiversity in threatened semi-natural grazed and mowed grasslands.

DOI： 10.1111/j.1654-109X.2012.01204.x

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Carbon dynamics during litter decomposition have been described in a variety of forest ecosystems and provided insights into carbon flow in soils. To quantitatively assess how decomposition processes vary between litter types, solid-state ¹³C cross-polarization and magic-angle spinning nuclear magnetic resonance (CPMAS NMR) technique was applied to analyze conifer (cedar, cypress) and hardwood (chinquapin, beech, oak, birch) litter which had degraded during a 3 year litterbag experiment throughout Japan. The results were used to identify compositional changes and estimate decomposition constants (k values) in exponential equations. Total litter and carbon type mass losses during decomposition varied significantly between litter types, being affected by the initial physicochemical litter quality. Concomitant increases and decreases in carbonyl and O/N-alkyl C compositions, respectively, were observed for all litter types, but aromatic and aliphatic C dynamics were less consistent. In hardwoods, [aromatic/aliphatic C ratio] was generally stable during decomposition, suggesting that, in hardwoods, the decomposabilities of aromatic and aliphatic C were similar. In the conifers, an increasing [aromatic/aliphatic C ratio] during decomposition suggested that aromatic C was more recalcitrant than aliphatic C. These results suggest that different decomposition processes between litter types might be related to different aromatic and aliphatic C behaviors, as affected by lignin stability and lipid leachability and biosynthesis. Variations in the k values for total litter and carbon types were not obvious between litter types, although the mass loss patterns differed significantly. The k values estimated in this study may contribute to predictions of soil carbon dynamics and the validation of carbon compartment models in forest ecosystems.

DOI： 10.1007/s10533-011-9682-z

記述言語：英語   掲載種別：研究論文（学術雑誌）  

1-O-cis-cinnamoyl-beta-D-glucopyranose is one of the most potent allelochemicals isolated from Spiraea thunbergii Sieb. It is suggested that it derives its strong inhibitory activity from cis-cinnamic acid, which is crucial for phytotoxicity. It was synthesized to confirm its structure and bioactivity, and also a series of cis-cinnamic acid analogues were prepared to elucidate the key features of cis-cinnamic acid for lettuce root growth inhibition. The cis-cyclopropyl analogue showed potent inhibitory activity while the saturated and alkyne analogues proved to be inactive, demonstrating the importance of the as-double bond. Moreover, the aromatic ring could not be replaced with a saturated ring. However, the 1,3-dienylcyclo-hexene analogue showed strong activity. These results suggest that the geometry of the C-C double bond between the carboxyl group and the aromatic ring is essential for potent inhibitory activity. In addition, using several light sources, the photostability of the cinnamic acid derivatives and the role of the C-C double bond were also investigated. (c) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.phytochem.2012.08.001

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Isolation and identification of novel allelochemicals and utilization of allelopathic cover plants for sustainable agriculture

記述言語：日本語  

2011年6月に世界自然遺産として正式に登録された小笠原諸島は，その独特の自然生態系に注目が集まっているが，その自然生態系を支える物質循環の基礎は土壌にある。すなわち，小笠原の土壌を調べれば，小笠原における物質循環の特徴についてヒントが得られると考えられる。小笠原における物質循環については，研究事例はこれまで非常に少ないが，ここでは著者らがこれまでに調べた小笠原の土壌に関するデータを中心に整理し，小笠原における物質循環の特徴を考察する。

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We analyzed the physicochemical and spectroscopic properties of three charred plant fragments (CPF) that were isolated from three volcanic ash soils in Japan. Values of delta C-13 showed that the CPF originated from C-3 and C-4 plants. The contribution ratio of C-4 plants to the CPF was much higher in Soils 1 and 3 than in Soil 2. Values of delta N-15 of the CPF were higher in Soil 3 isolated from the deeper soil horizons. Light reflectance values suggested that part of the CPF experienced combustion temperatures higher than 400 degrees C in Soil 2 and less than 400 degrees C in the other soils, respectively. Atomic [H]/[C] and [O]/[C] ratios suggested that the CPF were subjected to weathering ( oxidative degradation and hydrolysis) in soil for a long period after burning. The degree of weathering was considered to be larger in Soils 1 and 3. Spectra of C-13-NMR of the CPF, except the area of alkyl-C, were similar. Infrared (IR) spectra of three CPF, except aliphatic C-H stretching, were also similar to each other. The X-ray diffraction patterns of the CPF in Soil 2 clearly revealed the presence of graphite-like structure. From these findings, it was assumed that the physicochemical and spectroscopic characteristics of the CPF were strongly influenced by the type of burnt vegetation.

DOI： 10.1097/SS.0b013e31828047ab

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Overcoming the Difficulties in Collecting Apoplastic Fluid from Rice Leaves by the Infiltration-Centrifugation method
Physiological and biochemical studies on the leaf apoplast have been facilitated by the use of the infiltration-centrifugation technique to collect intercellular washing fluid (IWF). However, this technique has been difficult to implement in rice (Oryza sativa L.) for various reasons. We compared the collection efficiency of leaf IWF between two types of rice varieties (Indica and Japonica), as well as between rice and other species (spinach, snap bean and wheat). Although the extraction of IWF in most species took only 2-3 min, it took up to 35 min in rice. The difficulty in infiltration with rice was ascribed to the small stomatal aperture and hydrophobicity of the leaves. In this study, we have established an improved method for collecting IWF and determining the apoplastic air and water volumes in rice leaves. We have shortened the infiltration time to 8 min via the following improvements: (i) infiltration under outdoor shade in the daytime to prevent stomatal closure and a rise in temperature of the infiltration medium; (ii) soaking of leaves in a surfactant solution to decrease the leaf hydrophobicity; and (iii) continuous pressurization using a sealant injector to facilitate the infiltration. The rapid collection of IWF achieved using this technique will facilitate study of the leaf apoplast in rice.

DOI： 10.1093/pcp/pcs102

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A crude methanol extract of Goniothalamus andersonii J. Sinclair strongly inhibited elongation of lettuce (Lactuca saliva L.) radicles. We conducted bioassay-guided purification of G. andersonii bark extract and obtained goniothalamin as the major bioactive compound. Its EC50 values against elongation of lettuce radicles and hypocotyls were 50 and 125 mu mol L-1, respectively. Among the six species tested, timothy was the most sensitive to goniothalamin. Quantification of this compound in other Goniothalamus species suggested that the plant inhibitory activity of this genus is explainable by goniothalamin, with G. calcareus as an exception.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To improve the biodegradation of biodegradable plastic (BP) mulch films, 1227 fungal strains were isolated from plant surface (phylloplane) and evaluated for BP-degrading ability. Among them, B47-9 a strain isolated from the leaf surface of barley showed the strongest ability to degrade poly-(butylene succinate-co-butylene adipate) (PBSA) and poly-(butylene succinate) (PBS) films. The strain grew on the surface of soil-mounted BP films, produced breaks along the direction of hyphal growth indicated that it secreted a BP-degrading enzyme, and has directly contributing to accelerating the degradation of film. Treatment with the culture filtrate decomposed 91.2wt%, 23.7wt%, and 14.6wt% of PBSA, PBS, and commercially available BP polymer blended mulch film, respectively, on unsterlized soil within 6 days. The PCR-DGGE analysis of the transition of soil microbial community during film degradation revealed that the process was accompanied with drastic changes in the population of soil fungi and Acantamoeba spp., as well as the growth of inoculated strain B47-9. It has a potential for application in the development of an effective method for accelerating degradation of used plastics under actual field conditions

DOI： 10.1186/2191-0855-2-40

記述言語：日本語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Mealybugs, which include several agricultural pests, are small sap feeders covered with a powdery wax. They exhibit clear sexual dimorphism; males are winged but fragile and short lived, whereas females are windless and less mobile. Thus, sex pheromones emitted by females facilitate copulation and reproduction by serving as a key navigation tool for males. Although the structures of the hitherto known mealybug pheromones vary among species, they have a common structural motif; they are carboxylic esters of monoterpene alcohols with irregular non-head-to-tail linkages. However, in the present study, we isolated from the Matsumoto mealybug, Crisicoccus matsumotoi (Siraiwa), a pheromone with a completely different structure. Using gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy, we identified the pheromone as 3-methyl-3-butenyl 5-methylhexanoate. Its attractiveness to males was confirmed in a series of field trapping experiments involving comparison between the isolated natural product and a synthetic sample. This is the first report of a hemiterpene mealybug pheromone. In addition, the acid moiety (5-methylhexanoate) appears to be rare in insect pheromones.

DOI： 10.1007/s00114-012-0935-z

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Quantification of Cyanamide in Young Seedlings of Vicia Species, Lens culinaris, and Robinia pseudo-acacia by Gas Chromatography-Mass Spectrometry
We quantified the cyanamide content of young leaves of nine Vicia species, Lens culinaris, and Robinia pseudoacacia using a modified analytical procedure that made it possible to measure the cyanamide content of a single leaf. Recent molecular phylogenetic analysis suggests that cyanamide is present in V. benghalensis, which is placed in a monophyletic group with cyanamide-bio-synthesizing plants, V. villosa and V. cracca; this suggestion was verified.

DOI： 10.1271/bbb.120262

記述言語：日本語  

本シンポジウムでは,(1)土壌に炭化物を施用することで炭素貯留効果とともに農地土壌の改良効果を狙った応用的な研究をレビューするとともに,(2)炭化物研究を進めるにあたって不可欠な炭化物分析法についてとりまとめ,(3)日本の土壌中における炭化物の研究についてこれまでの知見から最新のデータまでを含めてレビューした。

DOI： 10.20710/dojo.83.2_222

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Batch adsorption and consecutive desorption experiments were performed under different pH conditions to assess the pH dependency of 2,4-dichlorophenoxyacetic acid (2,4-D) adsorption and desorption in Andosol (having pH-dependent surface charge characteristics) and kaolinite. The adsorption-desorption isotherms for both Andosol and kaolinite were well fitted by the Freundlich isotherm model. Adsorption of 2,4-D onto Andosol increased markedly with decreasing pH and was higher than for kaolinite under the same pH condition. Hysteresis, expressing the nonsingularity of the desorption compared with the adsorption isotherm, was found at all concentrations and each pH for both Andosol and kaolinite. For Andosol, the fitted Freundlich parameters for desorption, K(f,d) and n(d), showed a negative, linear and a positive, exponential relationship, respectively, with pH. Higher hysteresis index (omega), expressing the degree of partial irreversibility of 2,4-D adsorption, was obtained under lower pH, indicating that less adsorbed 2,4-D was released back from the Andosol under acidic condition. The effect of pH on 2,4-D desorption from kaolinite was less pronounced as compared with Andosol. Combining the measured data in this study with previously reported data on 2,4-D adsorption-desorption in several types of soil including Andosols, the possible mobility of adsorbed 2,4-D in soil was evaluated. Results show that adsorbed 2,4-D in soils exhibiting a total adsorption percentage of less than 55&#37; of the applied pesticide typically exhibited a greater potential to be mobile in the soil-water system. Opposite, a total adsorption percentage greater than 55&#37; implied higher residual adsorption and a prolonged existence of adsorbed 2,4-D in the soils.

DOI： 10.1097/SS.0b013e3182376ef3

記述言語：日本語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

ISOLATION OF UMBELLIFERONE AS A PRINCIPAL ALLELOCHEMICAL FROM THE PERUVIAN MEDICINAL PLANT Diplostephium foliosissimum (Asteraceae).

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The genesis of a 40-cm-thick buried Holocene humic soil horizon in a 6-m-high sequence near Towada volcano, Japan, was examined by dating stable, plant-derived humin particles by AMS-based radiocarbon (C-14), and by analyzing stable carbon isotope ratios (delta C-13), phytolith composition, and soil chemical properties. The AMS dating yielded calibrated ages ranging from 7570-7679 to 6180-6313 cal yr BP. We obtained a strong correlation (r = 0.99, ***p<0.001) between sample depth and the mean age. The (now buried) humic soil was formed by the incremental accumulation of tephric loess and aeolian dust at a constant rate of similar to 30 mm per century for at least 1200 years. Whilst the soil surface was slowly rising, graminaceous vegetation was supplied at a constant rate so that developmental upbuilding pedogenesis ensued. The soil was buried and isolated by the fall of the Towada-Chuseri tephra about 6200 cal yr BP. Thus the tephra-soil sequence near Towada volcano represents both developmental and retardant upbuilding pedogenesis. (C) 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.geoderma.2011.08.011

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We investigated 10 soils from six states in the United States to determine the relationship between potentiometric titration derived soil surface charge and the concentration of water-extractable P (WEP). Phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy was used to determine the chemical speciation of soil P. The surface charge value at the native soil pH was correlated to the WEP concentration, indicating that electrostatic interactions are involved in determining soil phosphate solubility. The titration curves were fit to a two-site Langmuir model and analysis showed that the native pH surface charge was accounted for by the low pH Type 1 (S-OH(2)(+)) site, attributed to positively charged metal (oxy) hydroxides. The (31)P NMR data indicated that 98&#37; of the inorganic form of P was composed of orthophosphate species and 95&#37; of the organic P was composed of the P monoester class compounds. The inorganic orthophosphate form of P was directly related to the total soil P content, suggesting that external fertilizer inputs control the level of this form of soil P. In contrast, P monoester class compound content was not related to total soil P content, suggesting that organic soil P is controlled by P cycling independent of external P inputs. The (31)P NMR speciation data indicated that the inorganic orthophosphate, pyrophosphate, and DNA P concentrations in the soils were significantly associated with oxalate-extractable Al and Fe concentrations, which further demonstrates that metal (oxy) hydroxides are important surfaces where P species are interacting with soils.

DOI： 10.2136/sssaj2010.0404

記述言語：日本語  

Present and future of soil testing : A star-studded-linup of schools

DOI： 10.20710/dojo.82.2_173

記述言語：英語   掲載種別：研究論文（学術雑誌）  

An aseptic bioassay utilizing female and male donor materials was performed in order to assess the allelopathic activities of cladophylls and root systems in dioecious asparagus. The aseptic sandwich method revealed that the growth of acceptor plants was significantly inhibited by the addition of over 30 mg fresh weight of cladophylls. When female and male cladophylls were separately adopted for the sandwich method, there was no sexual difference in the allelopathic activity of both youthful and senescent cladophylls. To detect the allelopathic effects of root systems, the plant box method employing female and male regenerants was used aseptically, and the growth of acceptor plants was seriously inhibited irrespective of sex expression in donor plants. Early in vitro flowering seedlings expressing individual sex were effectively used for the bioassay, and the results indicated that the degree of allelopathic activities was the same as that in regenerants. These results show that allelopathic activity in female and male plants was equivalent, and that the application of materials that can distinguish between the sexes would be useful for assaying the mutual effects of sexuality on allelopathy. The aseptic bioassay system that employed female and male materials presented here could promote the isolation and identification of allelochemicals.

DOI： 10.2503/jjshs1.80.169

記述言語：日本語  

日本原産のシランのアレロパシーとその原因物質の同定

記述言語：日本語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Velvetbean (Mucuna pruriens) plants impede the growth of neighboring plants. One compound, 3-(3',4'-dihydroxyphenyl)-l-alanine (l-DOPA), is responsible for the allelopathic capacity of velvetbean. This compound is an active allelochemical that decreases root growth of several plant species. In mammals, l-DOPA is a well-known therapeutic agent for the symptomatic relief of Parkinson's disease. However, its mode of action in plants is still not well understood. To address such issues, gene expression in Arabidopsis thaliana plants, which had been exposed to l-DOPA, was analyzed using DNA microarrays. After 6 h of l-DOPA exposure, the expression of 110 genes was significantly upregulated, and the expression of 69 genes was significantly downregulated. These induced genes can be divided into different functional categories, mainly on the basis of subcellular localization, metabolism, and proteins with a binding function or cofactor requirement. Based on these results, we suggest that l-DOPA acts by two mechanisms: it influences amino acid metabolism and deregulates metal homeostasis, especially that of iron, which is required for the fundamental biological processes of all organisms.

DOI： 10.1007/s00425-010-1294-7

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In this study, we discovered and isolated an attractant for a mealybug-parasitic wasp Anagyrus sawadai from an esterification product prepared with commercialized lavandulol (2-isopropenyl-5-methyl-4-hexen-1-ol) and butyryl chloride. Using gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy, we determined the structure of the compound to be (2,4,4-trimethyl-2-cyclohexenyl)methyl butyrate (cyclolavandulyl butyrate). This is a novel compound as far as we know, although the alcohol moiety has been known as a cyclization product from lavandulol. Cyclolavandulyl butyrate has two enantiomers, and the (-)-isomer, which is suggested to have S configuration, showed higher attractiveness. A potential use for the A. sawadai attractant for mealybug management in agricultural fields is discussed.

DOI： 10.1007/s13355-010-0012-z

記述言語：英語   掲載種別：研究論文（学術雑誌）  

An aseptic bioassay system to estimate allelopathy in asparagus calluses was established. Allelopathic activities of calluses were measured according to the callus packed cell volume (PCV) by means of the sandwich method, and remarkable inhibition of acceptor plants was observed by the addition of over 0.1 mL PCV. When female and male calluses were separately used for the sandwich method, there was no sexual difference in allelopathic activity. To detect the allelopathic activities of the callus cells in detail, we improved the plant box method that substituted the calluses for the seedlings, and serious inhibition of acceptor plants was observed with the addition of over 0.35 mL PCV as donor material. Allelopathic activities were accelerated by irradiating the calluses with light-emitting diodes (LEDs) prior to performing the aseptic bioassay. It also seemed that the light quality would affect their activities. The allelopathic activity appeared intensely with irradiation of the calluses with a blue LED. The aseptic bioassay system that employed LED-irradiated calluses established here could accelerate effectively the isolation and identification of allelochemical(s).

DOI： 10.2503/jjshs1.80.82

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The mycotoxin deoxynivalenol (DON) causes serious problems worldwide in the production of crops such as wheat and barley because of its toxicity toward humans and livestock. A bacterial culture capable of degrading DON was obtained from soil samples collected in wheat fields using an enrichment culture procedure. The isolated bacterium, designated strain WSN05-2, completely removed 1,000 mu g/mL of DON from the culture medium after incubation for 10 days. On the basis of phylogenetic studies, WSN05-2 was classified as a bacterium belonging to the genus Nocardioides. WSN05-2 showed significant growth in culture medium with DON as the sole carbon source. High-performance liquid chromatography analysis indicated the presence of a major initial metabolite of DON in the culture supernatant. The metabolite was identified as 3-epi-deoxynivalenol (3-epi-DON) by mass spectrometry and (1)H and (13)C nuclear magnetic resonance analysis. The amount of DON on wheat grain was reduced by about 90&#37; at 7 days after inoculation with WSN05-2. This is the first report of a Nocardioides sp. strain able to degrade DON and of the yet unknown 3-epi-DON as an intermediate in the degradation of DON by a microorganism.

DOI： 10.1007/s00253-010-2857-z

記述言語：英語   掲載種別：研究論文（学術雑誌）  

An aseptic bioassay utilizing female and male donor materials was performed in order to assess the allelopathic activities of cladophylls and root systems in dioecious asparagus. The aseptic sandwich method revealed that the growth of acceptor plants was significantly inhibited by the addition of over 30 mg fresh weight of cladophylls. When female and male cladophylls were separately adopted for the sandwich method, there was no sexual difference in the allelopathic activity of both youthful and senescent cladophylls. To detect the allelopathic effects of root systems, the plant box method employing female and male regenerants was used aseptically, and the growth of acceptor plants was seriously inhibited irrespective of sex expression in donor plants. Early in vitro flowering seedlings expressing individual sex were effectively used for the bioassay, and the results indicated that the degree of allelopathic activities was the same as that in regenerants. These results show that allelopathic activity in female and male plants was equivalent, and that the application of materials that can distinguish between the sexes would be useful for assaying the mutual effects of sexuality on allelopathy. The aseptic bioassay system that employed female and male materials presented here could promote the isolation and identification of allelochemicals.

DOI： 10.2503/jjshs1.80.169

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Formation and stabilization mechanisms of soil humic substances

DOI： 10.11519/jfsc.123.0.H13.0

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.4157/ejgeo.6.104

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We quantitatively clarified the early humification processes on Japanese cedar and Hinoki cypress forest floors by using a litterbag experiment and the solid-state ¹³C CPMAS NMR technique. There was no significant effect on litter mass loss during early humification between both coniferous litters regardless of the shape of their needles. Carbon composition in both litters showed similar trends during early humification. A/O-A as a humification index was low, around 0.6, in both litters throughout the experiment period although 60% of litter mass was lost. Coniferous litter incubated for 3 years might not be well-humified and would be susceptible to physical fragmentation. Carbon mass loss rates in conifers were in the following order: O-alkyl > aliphatic > aromatic > carbonyl carbons, differing with hardwoods. Conifers had concomitantly higher and lower mass loss rates of aliphatic and aromatic carbons than hardwoods. Soil organic carbon (SOC) accumulated in topsoil for conifers had relatively high and low contents of aliphatic and aromatic carbons than that for hardwood. These compositional differences of SOC among forests could be caused by the high and low supply rates of aliphatic and aromatic carbons from litter to topsoil. Consequently, initial litter nature and humification processes can affect the compositional qualities of SOC accumulated in soil.

DOI： 10.1007/s11104-010-0397-z

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Double-low rapeseed cultivars that produce no erucic acid and have only a small amount of glucosinolates are widely used. However, the roots in mature plant residue and leaves and roots of these seedlings still contain a large amount of biologically active glucosinolates, and it is important to clarify the effect of rapeseed cultivation on the subsequent crops. We analyzed the biological activities of the tissues of double-low cultivar at harvest. The laboratory bioassays revealed that the seeds and roots of mature rapeseed plants contained some autotoxic components that were volatile and water-soluble. We also analyzed the effects of root exudates from growing rapeseed plants on rapeseed germination and growth using the stair-step method and found that the root exudates were autotoxic. In the field, we investigated the allelopathic effects of rapeseed plants on the growth, yield, and quality of the subsequent sunfl ower plant in the same field. The growth, yield and thousand kernel weight of sunfl ower were reduced by the preceding cultivation of rapeseed. There were many spontaneously germinated juvenile rapeseed plants in the sunfl ower field preceded by rapeseed cultivation. Analysis of the plant and soil nitrogen (N) indicated that the growth reduction of sunfl ower was not caused by the competition for N with the spontaneously germinated juvenile rapeseed plants. The main factors responsible for poor sunflower growth under field after the cultivation of rapeseed were suggested to be some non-volatile, water-soluble components produced by the roots of the spontaneously germinated juvenile rapeseed.

DOI： 10.1626/pps.14.339

記述言語：英語   掲載種別：研究論文（学術雑誌）  

An aseptic bioassay system to estimate allelopathy in asparagus calluses was established. Allelopathic activities of calluses were measured according to the callus packed cell volume (PCV) by means of the sandwich method, and remarkable inhibition of acceptor plants was observed by the addition of over 0.1 mL PCV. When female and male calluses were separately used for the sandwich method, there was no sexual difference in allelopathic activity. To detect the allelopathic activities of the callus cells in detail, we improved the plant box method that substituted the calluses for the seedlings, and serious inhibition of acceptor plants was observed with the addition of over 0.35 mL PCV as donor material. Allelopathic activities were accelerated by irradiating the calluses with light-emitting diodes (LEDs) prior to performing the aseptic bioassay. It also seemed that the light quality would affect their activities. The allelopathic activity appeared intensely with irradiation of the calluses with a blue LED. The aseptic bioassay system that employed LED-irradiated calluses established here could accelerate effectively the isolation and identification of allelochemical(s).

DOI： 10.2503/jjshs1.80.82

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Ogasawara Islands are important ecosystems sustaining many indigenous spices. To clarify the indigenous soil environments of Ogasawara Islands, we studied the chemistry of the soils. Many surface soils were low in bio-available P (0 to 0.55 g P(2)O(5) kg(-1), average: 0.04 g P(2)O(5) kg(-1) as Bray II P, n = 22), but several soils were found to contain extremely large amounts of bio-available P (1.36 to 6.98 g P(2)O(5) kg(-1), average: 2.93 g P(2)O(5) kg(-1), n = 5). From soil profile analyses, the authors concluded that the extremely large amount of bio-available P could not be explained by the effects of parent materials with high P contents nor the effect of fertilizations by human activity, but the effects of natural seabird activities in the past could be the cause. The soil profiles with large amounts of bio-available P indicate deep migration of soil materials from A horizons, which could be a result of intensive mixing of upper horizons by seabird activities. The intensive mixing was supported by the low mechanical impedance of the horizons for the P-accumulating soils (8.17 +/- 2.54 kg cm(-2), n = 8) than those for the non-P-accumulating soils (17.46 +/- 3.52 kg cm(-2), n = 36). It is likely that in the past seabirds, such as shearwaters, made burrows in the soils for nesting and propagating and inadvertently transported a large amount of P from the sea to the soils, resulting in the extremely large amounts of bio-available P in the present soils. (C) 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.geoderma.2010.09.008

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The ¹³C labels of [¹³C]carbon dioxide and D-[ ¹³C₆]glucose were incorporated into cyanamide (NH2CN) when they were administered to Vicia villosa subsp. varia shoots. In contrast, the administration of sodium [2,3-¹³C₂]pyruvate did not affect the relative area of the [M + 1]⁺ ion of cyanamide in the gas chromatography-mass spectrometry analysis. [2,3-¹³C ₂]Pyruvate was incorporated into organic acids that are part of the citric acid cycle, such as succinate and fumarate, confirming that the shoots absorbed and metabolised it. These observations demonstrated that the carbon atom of cyanamide is derived from any of the carbohydrates that are present upstream of pyruvate in the metabolic pathway.

DOI： 10.1080/14786419.2010.482050

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The methanol extract of Bletilla striata, an ornamental orchid in eastern Asia, exhibited plant growth-inhibitory activity. It was purified by continuous chromatography, based on the inhibitory activity against the growth of lettuce seedlings, resulting in two glycosidic compounds, militarine and dactylorhin A. The EC(50) values of militarine and dactylorhin A against the radicle elongation of the lettuce seedlings were 0.28 and 0.88 mmol L-1, respectively. The amount of militarine and dactylorhin A in the methanol extract of the aerial part of B. striata was calculated to be 5.6 and 7.5 mg g-1 fresh weight, respectively. The inhibitory activity of militarine and its content in the methanol extract revealed that the plant growth-inhibitory activity of the extract of B. striata was mainly related to militarine. The inhibitory activity of militarine against the growth of Italian ryegrass and timothy were of the same level as that of lettuce.

DOI： 10.1111/j.1445-6664.2010.00385.x

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The allelopathic potential of a plant has been evaluated on the basis of two indicators: specific activity, which is the specific concentration of the allelochemical to exert a half-maximum effect on a receiver plant (EC50), and total activity in a plant, which is the ratio of the concentration of an allelochemical in the producing plant to its EC50. In the present study, a new indicator, total activity in a soil, which takes into account the effects of a soil on the allelopathy activity, is proposed because allelopathic activity is affected by the presence of soils. The total activity in a soil was calculated by multiplying the "total activity in a plant" with a "soil factor." In this calculation, we assumed simplified cases for comparison, such that the allelopathic plant materials are evenly incorporated in the soils and the allelochemicals are released from the plant materials to the soils at a constant rate. We conducted bioassay experiments in the presence and absence of soils and cited some published data to calculate the specific activities and total activities in a plant and in a soil. The results indicated that the allelopathies of buckwheat caused by ()-catechin, Leucaena leucocephala by l-mimosine, Xanthium occidentale by trans-cinnamic acid, and Brassica parachinensis by cis-cinnamic acid were not significant in a volcanic ash soil, an alluvial soil, and a calcareous soil, but the allelopathy of sweet vernalgrass caused by coumarin and Spiraea thunbergii by cis-cinnamoyl glucosides was highly effective in those soils. The allelopathies of Juglans species caused by juglone plus juglone precursors and Mucuna pruriens by l-DOPA would depend highly on the soil types. Although some limitations exist for this approach, the total activity approach would allow for a better quantitative estimation of the allelopathic potential of plant materials in soils.

DOI： 10.1614/WS-D-09-00085.1

記述言語：日本語  

ナガミヒナゲシはアレロパシー活性が強く、雑草化リスクが大きいので、広がらないようにする必要があります

記述言語：日本語  

ナギナタガヤのアレロパシーとそのアレロケミカルの同定

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： 10.18946/jssm.64.2_137_4

記述言語：日本語  

DOI： 10.20710/dojo.80.5_560

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To quantitatively clarify the organic carbon accumulation processes on the forest floor during an early stage of humification (3 years), solid-state ¹³C cross polarization magic angle spinning nuclear magnetic resonance (CPMAS NMR) signals were monitored for phased-humified beech and oak litters and soil surface horizons in the northern Kanto District, Japan. The mass loss rate of the carbon components during the humification for both litters was in the following order: O-alkyl > aromatic > aliphatic > carbonyl carbons. This result indicates that the labile O-alkyl carbons, probably dominated by holocellulose were selectively degraded compared to the other components. 44% of O-alkyl carbon mass for beech and 38% for oak lost throughout 3 years of incubation. Inversely, the mass of aliphatic carbons, which is mainly composed of saturated hydrocarbons, decreased quite slowly from 20 to 10% with humification, probably because a large proportion of the aliphatic carbons are secondary products of microorganisms. The aromatic carbon mass, which would be derived from lignin/tannin and their metabolites, also decreased gradually from 17 to 6% over 3 years. While, the carbonyl carbon mass was quite stable at around 2% throughout the incubation period, probably because the hydrolysis reactions of organic carbon would contribute to the formation of the carbonyl carbons. According to an exponential model, the total carbon stocks on the forest floor converged at 4.2 Mg C ha^{- 1} for the first few years at the studying site. The carbon compositions converged to intermediate levels between those of the F and A₁ horizons. The simulation in the present study is able to represent the carbon accumulation process on the forest floor including a part of the mineral.

DOI： 10.1016/j.geoderma.2009.05.001

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We isolated an antimicrobial compound from the aerial tissue of Geranium carolinianum and identified it as ethyl 3, 4, 5-trihydroxy benzoate (ethyl gallate) by ¹H-NMR and ¹³C-NMR and gas chromatography-mass spectrometry. The antimicrobial activity of ethyl gallate against three potato pathogens was assayed by the paper disk method. The activity against Ralstonia solanacerum, Streptomyces scabies, and Streptomyces acidiscabies was observed at concentrations >200, >300, and >300 μg disk ^-1, respectively. These results suggest that the antimicrobial activity of Geranium carolinianum against soil-borne plant disease pathogens is partly related to ethyl gallate.

DOI： 10.1111/j.1445-6664.2009.00335.x

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Natural cyanamide (NH₂CN) has recently been found in three Leguminosae plants: Vicia villosa subsp. varia, Vicia cracca and Robinia pseudo-acacia. As cyanamide has long been thought to be absent in nature, its physiological role and biosynthesis are totally unknown. In the present study, we demonstrated the incorporation of ¹⁵N from [¹⁵N]nitrate and [¹⁵N]ammonium into cyanamide using shoots of V. villosa subsp. varia, which ruled out the possibility that nodules are essential in cyanamide biosynthesis. We also applied [¹⁵N₂]cyanamide to shoots of V. villosa subsp. varia to monitor its turnover, and detected [ ¹⁵N₂]cyanamide in the leaves within 4 h; it was present without detectable degradation for more than 4 days. In contrast, maximum incorporation of ¹⁵N into cyanamide molecules was observed after 4 days of feeding the shoots with ¹⁵N-labeled inorganic ions and l-[amide-¹⁵N]-glutamine, indicating that these nitrogenous compounds are distant precursors of cyanamide. Although the guanidino group of l-arginine (-NH-C(NH₂)=NH) and urea (NH₂C(=O)NH₂) were candidate precursors of cyanamide on the basis of structural similarity, direct incorporation of the guanidino group of l-[¹³C₆, ¹⁵N₄]-arginine and [¹³C,¹⁵N ₂]urea into cyanamide was not observed. These results eliminated the possibility that cyanamide is biosynthesized by the addition of ammonia to an electrophilic carbon or by the conversion of the tested compounds that were structurally relevant to cyanamide.

DOI： 10.1111/j.1747-0765.2008.00354.x

記述言語：日本語  

Seed Germination : Physiology, Ecology and Molecular Mechanisms

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The quantification of the linear adsorption coefficient (K
_d) for soils plays a vital role to predict fate and transport of pesticides in the soil-water environment. In this study, we measured K
_d values for 2,4-Dichlorophenoxyacetic acid (2,4-D) adsorption onto Japanese volcanic ash soils with different amount of soil organic matter (SOM) in batch experiments under different pH conditions. All measurements followed well both linear and Freundlich adsorption isotherms. Strong correlations were found between measured K
_d values and pH as well as SOM. The 2,4-D adsorption increased with decreasing pH and with increasing SOM. Based on the data, a predictive K
_d equation for volcanic ash soils, log (K
_d) = 2.04 - 0.37 pH + 0.91 log (SOM), was obtained by the multiple regression analysis. The predictive K
_d equation was tested against measured 2,4-D sorption data for other volcanic ash soils and normal mineral soils from literature. The proposed K
_d equation well predicted K
_d values for other volcanic ash soils and slightly over- or under-predicted K
_d values for normal mineral soils. The proposed K
_d equation performed well against volcanic ash soils from different sites and countries, and is therefore recommended for predicting K
_d values at different pH and SOM conditions for volcanic ash soils when calculating and predicting 2,4-D mobility and fate in soil and groundwater.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

The influences of 46% hydrofluoric acid treatment on the organic compositional characteristics of phased-decomposing litters and surface soils.

DOI： 10.11519/jfsc.120.0.581.0

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Rhodotorula glutinis IFO1125 was found to acquire increased aluminium (Al) resistance from 50 mu M to more than 5 mM by repetitive culturing with stepwise increases in Al concentration at pH 4.0. To investigate the mechanism underlying this novel phenomenon, wild-type and Al- resistant cells were compared. Neither cell type accumulated the free form of Al (Al3+) added to the medium. Transmission electron microscopic analyses revealed a greater number of mitochondria in resistant cells. The formation of small mitochondria with simplified cristae structures was observed in the wild-type strain grown in the presence of Al and in resistant cells grown in the absence of Al. Addition of Al to cells resulted in high mitochondrial membrane potential and concomitant generation of reactive oxygen species (ROS). Exposure to Al also resulted in elevated levels of oxidized proteins and oxidized lipids. Addition of the antioxidants a-tocopherol and ascorbic acid alleviated the Al toxicity, suggesting that ROS generation is the main cause of Al toxicity. Differential display analysis indicated upregulation of mitochondrial genes in the resistant cells. Resistant cells were found to have 2.5- to 3-fold more mitochondrial DNA (mtDNA) than the wild-type strain. Analysis of tricarboxylic acid cycle and respiratory-chain enzyme activities in wild-type and resistant cells revealed significantly reduced cytochrome c oxidase activity and resultant high ROS production in the latter cells. Taken together, these data suggest that the adaptive increased resistance to Al stress in resistant cells resulted from an increased number of mitochondria and increased mtDNA content, as a compensatory response to reduced respiratory activity caused by a deficiency in complex IV function.

DOI： 10.1099/mic.0.2007/016048-0

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To elucidate the effects of broadcast urea on ammonia (NH₃) exchange between the atmosphere and rice, we investigated the NH₃ exchange flux between rice leaf blades and the atmosphere, xylem sap ammonium (NH₄⁺) concentration, leaf apoplastic NH₄ ⁺ concentration and pH, and determined the stomatal NH₃ compensation point. Paddy rice (Oryza sativa L. cv. Nipponbare) cultivation using experimental pots was conducted in the open air. Three treatments, no nitrogen (NN), standard nitrogen (SN) and high nitrogen (HN), were prepared for two supplemental fertilizations. Urea with 0, 30 and 60 kg N ha^-1 for the NN, SN and HN treatments, respectively, was broadcast at panicle initiation, and urea with 0, 20 and 40 kg N ha^-1 for the NN, SN and HN treatments, respectively, was broadcast at heading. The NH₃ exchange fluxes between the rice leaf blades and the atmosphere (SN treatment) measured using a dynamic chamber technique showed net deposition in general; however, net emission from the old leaves occurred 1 day after the application at heading. In contrast, the xylem sap NH₄⁺ concentrations increased markedly 1 day after both applications, which suggests direct transportation of NH₄⁺ from the rice roots to the above-ground parts. The applications resulted in no obvious increase in the leaf apoplastic NH₄⁺ concentrations. The relationship between the NH₄⁺ concentration in the xylem sap and that in the leaf apoplast was uncertain, although the NH₄⁺ in the xylem sap came from the roots and the NH₄⁺ in the apoplast might be affected by the stomatal deposition of NH₃. The stomatal NH₃ compensation point of rice was estimated to be 0.1-4.1 nmol mol^-1 air (20°C). The direction and intensity of the exchange flux through the stomata, interpreted on the basis of the temperature-corrected NH₃ compensation point, agreed with the observed exchange flux between the rice leaf blades and the atmosphere.

DOI： 10.1111/j.1747-0765.2008.00299.x

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Effects of soil chemical properties on the habitats of alien and endemic plants

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Root mucilage is gelatinous polysaccharide-containing material exuded from the outer layers of the root cap. Although mucilage has been suggested to play several roles in plant growth, its role in mineral uptake has not been well understood. Melastoma malabathricum L. is an aluminum (Al) accumulator growing in tropical acid soils. This species accumulates more than 10 mg Al g ^-1 DW in leaves and roots. Root mucilage is generally known to immobilize metal cations such as Al in the rhizosphere. However, we found that roots of M. malabathricum exuded large amounts of mucilage. Using the Zea mays L. mucilage as a control, we have recently shown that mucilage of M. malabathricum has unique physical and chemical characteristics, and facilitates Al uptake in this species. Since M. malabathricum cannot grow well in Al-deficient soil (nonacid soils), this species might have developed a mechanism for Al acquisition. We have also discussed the reason for this species' requirement of Al, a nonessential element.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Plant roots exude viscous polysaccharides, called mucilage. One of the suggested roles of mucilage is immobilization of toxic metal cations, including aluminum (Al), in the rhizosphere.
Mucilage exuded from roots of Melastoma malabathricum (Al accumulator) was characterized in comparison with that of Zea mays (maize; Al nonaccumulator).
Removal of mucilage significantly reduced Al accumulation in M. malabathricum. The cation adsorption affinity of M. malabathricum mucilage was higher for Al and lanthanum (La) than for barium (Ba), whereas that of maize mucilage was in the order Ba > La > Al. A (27)Al nuclear magnetic resonance (NMR) spectrum of the Al-adsorbed mucilage and bioassay with alfalfa seedlings indicated that the concentrated Al in the mucilage of M. malabathricum, unlike that of maize, bound very weakly to cation exchange sites of mucilage.
The higher charge density in M. malabathricum mucilage, derived from unmethylated uronic acid, is inferred to be related to preferential adsorption of trivalent cation. Not only a higher degree of methylation in the uronic acid (glucuronic acid) but also H(+) release from roots to the mucilage appears to be responsible for the loose binding of Al in M. malabathricum mucilage. These characteristics of mucilage may help Al hyperaccumulation in M. malabathricum.

DOI： 10.1111/j.1469-8137.2008.02397.x

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

X線、赤外線などの光を利用した分光分析技術は、植物・土壌中元素の定量・定性分析に古くから活用されてきた。近年、シンクロトロン放射光源の出現によりその応用範囲は拡大し、放射光は土壌肥料学分野においても有力な分析ツールとして注目されている。放射光とは、ほぼ光速で直進する荷電粒子がその進行方向を磁場の中で変えられる際に発生する光（電磁波）であり、円環状の粒子加速器であるシンクロトロンを利用することによって得られる。シンクロトロン放射光のメリットを活かした研究例として、まずX線マイクロビームを利用した蛍光X線分析による無機元素のイメージング（特定元素の分布の可視化）が挙げられる。輝度および平行度の高いシンクロトロン放射光は、μmスケールまで絞っても、植物・土壌中に存在する微量元素を励起できることから、微小領域の蛍光X線分析に利用できる。たとえば植物中の微量元素の分布を組織・細胞レベルで検出できるマイクロ蛍光X線イメージング技術は、植物中の微量元素の動態を明らかにするために有効である。本シンポジウムでは、シンクロトロン放射光の利用を促進する目的で、土壌肥料関連分野におけるいくつかの研究例とともに、実際の利用方法や利用にあたっての注意事項などを紹介した。

記述言語：日本語  

DOI： 10.20710/dojo.79.2_245

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Cyanamide (NH2CN) has recently been proven to be a natural product, although it has been synthesized for over 100 years for agricultural and industrial purposes. The distribution of natural cyanamide appears to be limited, as indicated by our previous investigation of 101 weed species. In the present study, to investigate the distribution of natural cyanamide in Vicia species, we monitored the cyanamide contents in V villosa subsp. varia, V cracca, and V amoena during their pre-flowering and flowering seasons. It was confirmed that V cracca was superior to V villosa subsp. varia in accumulating natural cyanamide, and that V amoena was unable to biosynthesize this compound under laboratory condition examined. The localization of cyanamide in the leaves of V villosa subsp. varia seedlings was also clarified. In a screening study to find cyanamide-biosynthesizing plants, only Robinia pseudo-acacia was found to contain cyanamide among 452 species of higher plants. We have investigated 553 species to date, but have so far found the ability to biosynthesize cyanamide in only three species, V villosa subsp. varia, V. cracca and R. pseudo-acacia. (c) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.phytochem.2007.11.004

記述言語：日本語  

要注意外来植物ハリエンジュにもシアナミドが含まれる

記述言語：日本語  

簡易型雑草リスク評価法の提案とこれによるリスク評価

記述言語：日本語  

外来植物アカギに含まれる植物生育阻害物質はＬ－酒石酸

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Influence of light quality on allelopathic effects of asparagus through aseptic bioassay

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The adsorption of 2-(2,4-dichloro-3-methylphenoxy)propanoic acid (DMPA) on the surface horizon of a humus-rich Andosol was examined. To investigate the mechanisms of adsorption, chemically treated Andosols, such as organic matter removed Andosol, organic matter and active metals removed Andosol, and clay minerals of the Andosol, were prepared. Furthermore, humic acid was extracted from the Andosol. The mechanisms of the DMPA adsorption were identified by using those untreated and chemically treated Andosols and the humic acid. The amount of DMPA adsorbed increased with decreasing equilibrium pH value. Active surface hydroxyl groups were identified as the most important soil functional group in DMPA adsorption. The predominant mechanism of DMPA adsorption on the Andosol is a ligand-exchange reaction, in which an active surface hydroxyl on Al and/or Fe is replaced by a carboxylic group of DMPA. A comparative study revealed that the amount of DMPA adsorbed was slightly greater than that of (2,4-dichlorophenoxy)acetic acid (2,4-D), especially at equilibrium pH values below 5. This is because the octanol-water partition coefficient (log K(ow),) of DMPA in the equilibrium pH range is higher than that of 2,4-D, and SOM participates in the adsorption process through a hydrophobic interaction.

DOI： 10.1021/jf0729816

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Lipase-catalyzed asymmetric acetylation of a mixture of (6R,1′S,4′S,5′R)- and (6R,1′R,4′R,5′S)-7′-norsesquisabinen-4′-ol (3) afforded a separable mixture of the recovered former and the acetate of the latter. The recovered alcohol was oxidized to (6R,1′S,5′R)-sesquisabina ketone (2), whose absolute configuration could be assigned by its CD comparison with (1R,5S)-sabina ketone (4). Conversion of (6R,1′S,5′R)-sesquisabina ketone (2) to the bioactive pheromone revealed the stereostructure of the male aggregation pheromone of the stink bug Erysarcoris lewisi (Distant) to be (2Z,6R,1′S,5′S)-2-methyl-6-(4′-methylenebicyclo[3.1.0]hexyl)hept-2-en-1-ol (sesquisabinen-1-ol, 1).

DOI： 10.1016/j.tetlet.2007.11.036

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To determine the mechanism of aluminum (Al) detoxification in the roots of tea plants (Camellia sinensis (L.) Kuntze), the amounts of Al and Al-chelating compounds (fluoride (F), organic acids and catechins) were measured and the chemical forms of A, in root cell extracts were identified by the application of Al-27-nuclear magnetic resonance (NMR) spectroscopy. Tea plants were cultivated in nutrient solutions containing 0, 4, 1.0 and 4.0 mM of Al at pH 4.2 for approximately 10 weeks. The levels of soluble Al, water-soluble oxalate and citrate, but not F, malate or catechins in young roots increased with an increase in the concentration of Al in the treatment solution. The Al-27 NMR spectra of root tips and cell sap extracted from root tips that had been treated with Al were almost identical and had four signals, with two (11 and 16 ppm) apparently corresponding to the known chemical shifts of Al-oxalate complexes. In the spectra of cell sap, the resonances at 11 and 16 ppm increased with an increase in the Al contents. These results suggest that the levels of Al-oxalate complexes increased in response to an increase in the Al level, implying that oxalate is a key Al-chelating compound in the mechanism of Al detoxification in the tea root. (C) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.phytochem.2007.06.007

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A sex pheromone component of the Japanese mealybug, Planococcus kraunhiae, was isolated and identified. A crude extract of the pheromone obtained by airborne collection was first fractionated with Florisil column chromatography. The activity of each fractionated sample was examined in Petri dishes. The active fraction was further purified by HPLC and an active component was isolated by preparative GC. The purified compound showed attraction activity to adult males of P. kraunhiae in the field. The chemical structure was determined to be 2-isopropyliden-5-methyl-4-hexen-1-yl butyrate by GC-MS and NMR analyses.

DOI： 10.1303/aez.2008.369

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

The growth-inhibitory activity associated with allelopathy from bean was studied using the "Plant Box Method" and "Sandwich Method" in bioassays. By these methods, we confirmed that bean produced allelochemical substances from their roots. These methods also enabled to evaluate the effect of flowable activated carbon (activated carbon F) as one of the materials onto which the allelochemical substances were absorbed at a laboratory level.

DOI： 10.19016/hokurikucs.43.0_117

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A male-produced crude aggregation pheromone from Eysarcoris lewisi (Distant) (Heteroptera: Pentatomidae) was collected from volatiles emitted by adult males. It was purified with high performance liquid chromatography using a silica gel column, followed by preparative gas chromatography. The attraction activity of each fraction was field tested using water pan traps. The isolated compound of the aggregation pheromone component was analyzed by GC-MS and NMR, and the chemical structure was estimated to be (Z)-2-methyl-6-(4- methylenebicyclo[3.1.0]hex-1-yl)hept-2-en-1-ol.

DOI： 10.1303/aez.2008.11

記述言語：英語  

Mineral imbalance in high-input agricultural ecosystems has become an acute concern in many developed countries. Relapse into low-input agricultural ecosystems, however, will cause mineral stresses to crops, resulting in reduced food productions. Under such natural soil conditions, some endemic plants can tolerate the mineral stresses because they have evolved to adapt to the stresses. Numerous studies have been conducted to clarify the chemistry of the mineral elements of interest in rhizosphere and to utilize the tolerant mechanisms in plants. In this chapter, the authors reviewed the research progress on molecular scale mechanisms of Fe-deficiency, Al-toxicity, and P-deficiency stresses in soils and their tolerances by plants. In low Fe-availability conditions, two Fe-acquisition mechanisms of plants have been clarified: enhanced Fe dissolution in rhizosphere by secreted proton/reductants/chelators followed by reduction of Fe³⁺ to Fe²⁺ and specific uptake of Fe²⁺ (Strategy I) and Fe dissolution by secreted hexadentate Fe³⁺-transporting molecule (phytosiderophore) by forming Fe³⁺-phytosiderophore complex followed by specific uptake of the complex (Strategy II). Two tolerant mechanisms against high Al-toxicity of soils have been reported: exclusion of Al from cytoplasm (exclusion mechanism) and detoxification of Al in plants (internal detoxification mechanism). Phosphorous acquisition mechanisms of plants from low P-availability soils would be (1) alteration of root architecture, (2) secretion of organic acids, (3) secretion of phosphatase, and (4) enhanced expression of P transporter on roots. Some of the molecular mechanisms for the expression of the tolerances and their application to the genetic improvement are also reviewed.

DOI： 10.1016/S0065-2113(07)96004-6

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Cyanamide (NH_2CN) has been isolated from hairy vetch Vicia villosa subsp. varia as a natural product for the first time. We have already clarified that the cyanamide content in hairy vetch seedlings cultivated in the growth chamber reaches its maximum at 3-4 week. The present study aims at elucidating the organ in which cyanamide is biosynthesized. The cyanamide contents in the leaves, the stems, and the roots of 4-week-old seedlings were 629 ± 209, 256 ± 134, and < 20 μg/gFW (average ± SD), respectively. This suggests that cyanamide is biosynthesized in the aerial parts (the leaves plus the stems). To investigate the cyanamide-biosynthesizing organ, we compared the ^^<15>N incorporation into cyanamide in the whole aerial parts to that in the apical portion including the younger leaves. The ^^<15>N isotope abundance ratio in the isolated cyanamide was 3.99 ± 0.61% (average ± SE) when the whole aerial parts was incubated with ^^<15>N-labeled nitrogen sources, which was significantly higher than that of control (0.28 ± 0.03%). In contrast, the cyanamide isolated from the apical portion was not ^^<15>N-labeled on the same condition. These results imply that cyanamide is biosynthesized in the mature leaves.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Aseptic bioassay for estimation of asparagus allelopathic effects toward asparagus seeds

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A new scheme for fine fractionating and purifying a crude fulvic acid fraction was proposed. The fractionation procedure includes an adsorption process of the fulvic acid fraction on a hydrophobic resin (e.g. XAD-8 and DAX-8) and a sequence of successive elution processes. This procedure yields a non-adsorbed fraction (FA-1), a 0.1 mol L^-1 HCl eluted fraction (FA-2), a distilled water eluted fraction (FA-3) and a 0.1 mol L^-1 NaOH eluted fraction (FA-4). To remove salts and water, the fractionated organic molecules were co-precipitated with Al hydroxides at pH 5 and collected by centrifugation. Recoveries of carbon from the crude fulvic acid fraction of an Andosol were 42, 20, 19 and 14% for FA-1, FA-2, FA-3 and FA-4, respectively, and 96% of carbon was recovered in total. Optical properties and ¹³C nuclear magnetic resonance spectra indicated that the chemical properties of FA-1 were similar to those of FA-2 and were hydrophilic, while the chemical properties of FA-3 were very close to those of FA-4 and were hydrophobic (estimated hydrophobicity: humic acid >> FA-4 ≥ FA-3 >> FA-2 ≥ FA-1). A fulvic acid that can be isolated using the International Humic Substances Society method would be, in practice, a mixture of hydrophilic fulvic acid (FA-2) and hydrophobic fulvic acid (FA-3 + FA-4). The method developed in the present study will provide more detailed, quantitative and complete information of the fulvic acid fraction of soils.

DOI： 10.1111/j.1747-0765.2007.00159.x

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Sclerotium grains in soil contain humus-metal complexes that are probably produced from fungal metabolites. The characterization of major elements in sclerotium grains collected from volcanic ash soils in Mt Myoko was examined by X-ray photoelectron spectroscopy, FT-IR spectrometry and CHN analysis, and the concentration of trace elements was determined by PIXE (particle induced X-ray emission spectrometer) analysis. The content of major elements, C, H, N, O and Al, was approximately 47.6, 3.32, 0.78, 30.2 and 1.4% by mass, respectively. Trace elements such as Ti, Cr, Mn, Cu, Zn, Br and Pb were detected in the grains at concentrations between 10 and 100 μg g^-1. Functional carbon groups for the whole grain were characterized by the dominance of O-alkyl C associated with aromatic C. The comparison between the surface and subsurface (matrix) of the grain showed that the concentrations of O, C and N were relatively greater on the surface of sclerotium grains than in the matrix. The proportion of carbon having C-O, C=O, and O-C=O bonds, O and N showed a tendency to decrease from the surface towards the matrix. The proportion of C assigned as C-C and/or C-H bonds had a tendency to increase towards the matrix associated with Al.

DOI： 10.1111/j.1365-2389.2006.00868.x

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Dissolved organic matter (DOM) plays an important role in ecosystem processes such as nutrient release and utilization, mobilization and transport of metals, and carbon sequestration. We investigated the chemical properties of soils from the Bear Brook Watershed in Maine (BBWM) which is the site of a long-term paired-watershed experimental acidification study that includes both deciduous and coniferous stands. Multi-dimensional fluorescence spectroscopy combined with parallel factor analysis (PARAFAC) of the spectra, nuclear magnetic resonance spectroscopy, and size-exclusion chromatography, were used to characterize the DOM extracted from soils sampled from BBWM at four soil depth increments in 2003. Principal component analysis of the base cation, metal, and total C content of the mineral horizons indicated a strong negative relationship between pH and soil Al, Fe, P, and C. The close clustering of Al, Fe, P, and C loadings for the mineral soils suggests that organic matter is important for Al and Fe mobilization and that P solubility is influenced by the metal mobilization process. PARAFAC modeled the fluorescence spectra with three fluorescing components that were in the landscape regions typical of humic substances: (339 nm excitation/470 nm emission), (324 nm/418 nm), and (< 240/465 nm) and the relative distributions of the three components were similar amongst the four treatments and four soil depth increments. The size exclusion chromatograms also revealed a high degree of similarity between all the extracted DOM. Our data suggests that litter quality as influenced by forest composition and ecosystem acidification exert a minor influence on the chemical composition of the water-soluble soil DOM fraction.

DOI： 10.1016/j.geoderma.2007.04.004

記述言語：日本語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

¹⁴C ages and δ¹³C were examined for sclerotium grains to elucidate the characteristics of these grains distributed in forest soils. The ages of the grains from surface A horizons and buried A horizons were ca 100-200 bp and ca 300-1,200 bp, respectively. In comparison with humic acid extracts, the ¹⁴C ages were in the increasing order: humic acid fraction < humic acid Pg fraction < sclerotium grains. The δ¹³C values for sclerotium grains in surface A horizons and buried A horizons were approximately -31‰ to -28‰, and these values were approximately 2-4‰ smaller than those of humic acids and soils. The C content of the grains had a tendency to decrease with increasing ¹⁴C ages, while the C content of humic acid was constant with age. The ¹⁴C ages of sclerotium grains indicate the individual age of grain formation, which are more likely to assign closer ages to the beginning of soil forming than the ¹⁴C ages of humic acid. The low δ¹³C values for sclerotium grains have presumably originated from characteristically biological organics, which may be protected from attack in soils because of their structure.

DOI： 10.1111/j.1747-0765.2007.00121.x

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Aluminum (Al)-humus complexes are abundant in the A horizons of non-allophanic Andosols and contribute to the unique properties of volcanic ash soils, such as high reactivity with phosphate ions and a low bulk density. Natural non-allophanic Andosols commonly show Al toxicity to plant roots. There have been very few studies examining the contribution of Al-humus complexes to the Al toxicity of plant roots, although the complexes are the probable source of the toxic Al. We extracted humic substances from the A horizon of a non-allophanic Andosol using NaOH solution and reacted the humic substances and partially neutralized the AlCl₃ solution at three pH conditions (pH 4.0, 4.5 and 5.5) to prepare pure Al-humic substance complexes. The Al solubility study (equilibrium study in 10^-2 mol L^-1 CaCl₂) and the Al release study (a stirred-flow method using 10 ^-3 mol L^-1 acetate buffer solution adjusted to pH 3.5) indicated that all the synthetic complexes easily and rapidly release monomeric Al into the liquid phase with slight changes in pH and ion strength, although the Al contents and their extent of polymerization are considerably different among the complexes. A plant growth test was conducted using a medium containing the Al-humic substance complexes and perlite mixture. Root growth in burdock (Arctium lappa) and barley (Hordeum vulgare L.) was reduced equally by all three complex media, and the roots showed the typical injury symptoms of Al toxicity. These results indicate that in soils dominated by Al-humus complexes the Al released from the Al-humus complexes, as well as the exchangeable Al adsorbed by soil minerals, is definitely toxic to plant roots.

DOI： 10.1111/j.1747-0765.2007.00114.x

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A novel bacterial strain FJ1117YT was isolated from an enrichment culture with the herbicide simetryn. The isolate was capable of degrading the herbicide supplied as the sole sulfur source in an aquatic batch culture. The strain FJ1117YT was identified as that belonging to Rhodococcus sp. on the basis of comparative morphology, physiological characteristics and comparison of the 16S rRNA gene sequence. The biodegradation pathway of simetryn was established by isolating the methylsulfinyl analogue as the first metabolite and by identification of the methylsulfonyl intermediate and the hydroxy analogue by liquid chromatography-mass spectrometry (LC-MS) and/or nuclear magnetic resonance (NMR) analysis. The results indicate that the methylthio group was progressively oxidised and hydrolysed by the strain FJ1117YT. The same strain is also able to metabolise other methylthio-s-triazines such as ametryn, desmetryn, dimethametryn and prometryn through similar pathways.

DOI： 10.1002/ps.1331

記述言語：日本語  

小笠原父島に生育する樹木葉のアレロパシー活性の検定

記述言語：日本語  

ソバ粗抽出液に含まれる主要な植物生長阻害成分はルチン

記述言語：日本語  

コンフリーのアレロパシーと植物生育阻害物質の同定

記述言語：日本語  

Soil humic substances: their chemical structures and functions

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Varietal differences in allelopathic effects of asparagus seedlings

記述言語：英語   掲載種別：研究論文（学術雑誌）  

3-(3′,4′-Dihydroxyphenyl)-L-alanine (L-DOPA), which is synthesized in velvet bean (Mucuna pruriens), inhibits plant growth. The concentration of L-DOPA in soil is reduced by adsorption and transformation reactions, which can result in the reduction of its plant-growth-inhibitory activity. To determine which part of the L-DOPA structure is involved in the adsorption and soil transformation reactions, we compared the kinetics of L-DOPA disappearance in a volcanic ash soil with that of L-phenylalanine (3-phenyl-L-alanine) and L-tyrosine (3-(4′-hydroxyphenyl)-L-alanine), compounds that are similar in structure to L-DOPA but do not have a catechol (o-dihydroxybenzene) moiety. L-Phenylalanine and L-tyrosine were not adsorbed and transformed in the soil at equilibrium pH values between 4 and 7. These results suggest that the adsorption and transformation reactions of L-DOPA in the soil involve the catechol moiety and not the amino and carboxylic acid groups, which are common to all three compounds. Like L-DOPA, (+)-catechin, another allelochemical that contains a catechol moiety, underwent adsorption and soil transformation reactions. Thus, we concluded that the concentrations of allelochemicals bearing a catechol moiety in soils will decrease rapidly owing to adsorption and transformation reactions, and this decrease will be faster in soils with a high pH value or high adsorption ability. Owing to this decrease in concentration, allelopathic phenomena may not occur.

DOI： 10.1007/s10886-006-9218-5

記述言語：日本語  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Overview of General Presentations and Messages Mediated by the Congress

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To identify the important soil components involved in 2,4- dichlorophenoxyacetic acid (2,4-D) adsorption on Andosols, 2,4-D adsorption on a surface horizon of an Andosol was compared with that on hydrogen peroxide (H₂O₂)-treated (soil organic matter [SOM] was removed), acid-oxalate (OX)-treated (active metal hydroxides and SOM were removed), and dithionite-citrate-bicarbonate (DCB)-treated (free and active metal [hydr]oxides and SOM were removed) soil samples at equilibrium pHs ranging from 4 to 8. Although the untreated soil contained a large amount of organic C (71.9 g kg^-1), removal of SOM had little effect on 2,4-D adsorption. Active surface hydroxyls, which were attached to the active and free metal (hydr)oxides and metal SOM complexes, were identified as the most important soil functional group for 2,4-D adsorption. The dominant mechanism of the 2,4-D adsorption was a ligand exchange reaction in which the carboxylic group of 2,4-D displaced the active surface hydroxyl associated with metals and formed a strong coordination bond between the 2,4-D molecule and soil solid phase. The ligand exchange reaction reasonably accounted for the selective adsorption of 2,4-D over Cl ^-, competitive adsorption of phosphate over 2,4-D, reduction in plant-growth-inhibitory activity of soil-adsorbed 2,4-D, and the high 2,4-D adsorption ability of Andosols. Although a humic acid purified from the soil did not adsorb 2,4-D, the presence of the humic acid increased 2,4-D adsorption on Al and Fe, probably by inhibiting the hydrolysis and polymerization of Al and Fe resulting in the preservation of available adsorption sites on these metals. The adsorption behavior of 2,4-D on soils could be a good index for predicting the adsorption behavior of other organic acids in soils.

DOI： 10.2134/jeq2005.0415

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Three representative allophanic Andisols in Japan were evaluated by solid-state ¹³C, ²⁷Al, and ²⁹Si nuclear magnetic resonance (NMR) and stable isotopic ratio of carbon (δ¹³C). The solid-state cross polarization magic angle spinning (CPMAS) ¹³C NMR spectra were effective in characterizing crude soil C without any chemical treatment when soil C content was > 100 g C kg^{- 1}. Aliphatic, O-alkyl, and carbonyl C were relatively abundant in the uppermost horizons, whereas aromatic C was concentrated in the subsurface horizons, showing its persistence and tolerance to degradation in subsurface horizons. Contribution ratios of C4-plant-derived C (mainly from Miscanthus sinensis) on the total CR_C4 which were evaluated from δ¹³C value, were 35% to 42%, 59% to 62%, and 50% to 53% in subsurface horizons, and 12%, 23%, and 48% in uppermost horizons, for the three soils. The decline in CR_C4 values in the uppermost horizons could be an effect of recent vegetation. Solid-state ²⁷Al and ²⁹Si NMR revealed that most part of the tetrahedral Al in volcanic glass had already weathered into octahedral Al and a large amount of allophanic constituents (allophane, imogolite, allophane-like constituents including protoimogolite) was formed in B horizon within the past 25,000 ¹⁴C y. Allophanic constituents determined by ²⁹Si NMR were compared with those dissolved by acid-oxalate, and differences between them were discussed.

DOI： 10.1016/j.geoderma.2006.05.007

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Replanting of asparagus (Asparagus officinalis L.) often results in lower yields and extensive damage of young plants. One of the causes is considered allelopathy. In this study, we examined the participation of allelopathy on injury by continuous cropping of asparagus in alluvial soil. The presence of strong allelochemical substances, which have the growth-inhibitory activity, was detected by bioassay of rhizosphere soil around asparagus. This growth-inhibitory activity was not attributed to salt accumulation, pH fluctuation, or inorganic nutrient imbalance in the rhizosphere soil. Asparagus foliage incorporated into the soil did not demonstrate a close relation to the growth inhibition or decreased yield of asparagus. However, strong growth-inhibitory activity was demonstrated in the storage roots of asparagus. It is assumed that an allelochemical is exuded from the storage roots and is one of the causes of unsuccessful continuous cropping of asparagus.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

We developed a new method of examining the effects of allelochemical substances exuded from the roots of asparagus (Asparagus officinalis L.) to rhizosphere soil. This rhizosphere soil bioassay method provided results similar to those from the conventional bioassay method in which asparagus germinates in the soil. The new method was more effective than the conventional bioassay method because the soil samples could be tested using a smaller volume. This method could also evaluate flowable activated carbon as one of the materials to absorb allelochemical substances at a laboratory level. An appropriate orientation of cultivation is expected to become possible using the rhizosphere soil assay method developed in this study to examine obstructions to continuous cropping that may be related to allelopathy.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

The growth-inhibitory activities of allelopathy in asparagus (Asparagus officinalis L.) was studied using the 'Plant Box Method' of bioassay. By this methods we confirmed that asparagus produced allelochemical substances. Then we developed a modified plant box method to examine the relationship between the growth-inhibitory activity and the adsorption of materials to allelochemical substances from asparagus. As a result, a type of activated carbon has the ability to absorb the allelochemical substances and prevent the growth inhibition of lettuce, an assay plant. Furthermore, in a field replanted with asparagus, treatment with activated carbon increased the fresh weights of rhizomes and storage roots, as well as the number of storage roots, the growth amount, and the growth index (GI'), when compared to those of asparagus grown on non-treated plots.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Pant growth inhibitory activity of Lycoris radiata Herb. and the possible involvement of lycorine as an allelochemical

DOI： 10.1111/j.1445-6664.2006.00217.x

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Cyanamide (NH₂CN) is found in nature, although it has long been recognized as an industrial product. Distribution of cyanamide in the plant kingdom was investigated using a direct quantitative determination method to detect and measure cyanamide by stable isotope dilution gas chromatography-mass spectrometry (the SID-GC-MS method). The SID-GC-MS method proved to be a robust way to quantify cyanamide contents in the extracts of 101 species of herbaceous plants. The average recovery of cyanamide from all plants tested was 55:6 ± 20:3%. Vicia villosa and V. cracca contained cyanamide at 369-498 μg/gFW and 3,460-3,579 μg/gFW respectively, while the other 99 species contained no detectable cyanamide (< 1 μg/gFW). This result suggests that distribution of cyanamide in the plant kingdom is limited and uneven.

DOI： 10.1271/bbb.60171

記述言語：日本語  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Sexual differences in allelopathic effects of female and male asparagus roots

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Studies on allelopathy of asparagus

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Cyanamide (NH₂CN) has recently been isolated as a plant growth inhibitor from Vicia villosa, which is the first discovery of cyanamide from natural sources. To reveal the presence of the biosynthesized cyanamide in plants, 3.4mM potassium (¹⁵N)nitrate was administered to 15- to 35-day-old plants of V. villosa, from which the cyanamide was purified and subjected to GC/MS analysis. The isotopic ratio ¹⁵N/(¹⁴ N+¹⁵N) of the cyanamide was calculated to be 0.143, while that of the cyanamide extracted from V. villosa grown in the presence of a natural N source was 0.0065. The ¹⁵N-enrichment proved de novo biosynthesis of cyanamide.

DOI： 10.1080/14786410500143583

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The production of quorum-sensing-related signal molecules (QSRMs) among culturable bacteria comprising the community on wheat heads was investigated. The taxonomic position of 186 bacterial isolates obtained from ten heads was inferred based on 16S rRNA gene sequences, and their QSRM production was determined using two bioreporter strains of N-acylhomoserine lactones. Approximately 33% of isolates produced QSRMs, though the proportion of QSRM-producing isolates on a wheat head was significantly negatively correlated with population size. Most of the producing isolates were Pantoea species, most commonly Pantoea ananatis. Furthermore, the proportion of Pantoea ananatis that produced QSRMs was significantly negatively correlated with the number of bacterial genera (community richness) on each head. Finally, community richness was positively correlated with population size. Qualitative analysis using thin-layer-chromatography revealed that the QSRMs of Pantoea isolates were composed of at least two compounds. This is the first report indicating that Pantoea ananatis isolates inhabiting wheat heads are capable of producing QSRMs. QSRM production by Pantoea spp. may contribute to the predominance of this genus on wheat heads, particularly at relatively low population densities and community diversity.

DOI： 10.1139/W05-146

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Fulvic acids play an important role in the behavior of metals and hydrophobic organic chemicals in soil and water environments. The isolation and purification of the fulvic acids have been difficult to achieve, however, because these compounds are soluble in both alkaline and acidic solution, resulting in difficulty of dehydration and demineralization. We propose here a new procedure for isolating fulvic acids as precipitates. Our procedure includes pH-adjustment of the fulvic acid solution to weakly acidic to neutral pH range (4 to 7). In an Andisol, recoveries of the fulvic acids we prepared by precipitation at equilibrium pH of 5.0 were 86% (dissolved total organic carbon basis) and 97% (absorbance basis, 400 nm), whereas recoveries of fulvic acids adsorbed on XAD-8 resin (hydrophobic fulvic acids) were 14% and 28%, respectively. Recoveries of the fulvic acids were further increased in our procedure by adding Al. The mechanism forming the precipitates includes a complexation reaction of carboxylic groups of the fulvic acids with Al (ligand exchange reaction); this mechanism is identical to that for the retention of fulvic acids in many soils. Therefore, it is likely that our preparation procedure is appropriate for separating the fulvic acids stabilized in soils. Solid-state cross polarization and magic angle spinning ¹³C nuclear magnetic resonance spectra showed that the fulvic acids prepared by our precipitation procedure were relatively rich in O-alkyl carbons and poor in aromatic and alkyl carbons compared with those forms from the hydrophobic fulvic acids adsorbed on XAD-8 resin. A new scheme for preparing the hydrophobic and hydrophilic fulvic acids is also proposed here. The hydrophilic fulvic acids are likely to maintain high solubilities in water even after the formation of complexes with metals and may influence on their behavior.

DOI： 10.1016/j.geoderma.2005.05.007

記述言語：日本語  

Potential Allelochemicals from comfrey (Symphytum officinale L.)

記述言語：日本語  

Total activity of selected allelochemicals identified in buckwheat.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Most of the plants morphologically identified as the introduced dandelions are known to be the hybrids between the native diploid and the introduced triploid dandelions. From the viewpoint of environmental indicator species, we clarified the environmental characteristics of the habitats of native and hybrid dandelions ("tetraploid hybrids" and "triploid hybrids"), analyzing the relationships between the distribution pattern of these dandelions and the habitat factors such as vegetation types, soil pH (H_2O), soil hardness and illumination intensity in the campus of the National Institute of Livestock and Grassland Science. It was found that the native dandelions mainly occurred at slightly disturbed habitats with weakly acidic soil covered by forest edge species. In contrast, the hybrid dandelions, typically tetraploid hybrids, tended to occur at intensively disturbed habitats with relatively hard soil of neutral pH (H_2O). We also performed clone analysis to reveal the genetic structures of dandelion populations, and analyzed the distribution patterns of each of the genetically identical clones. Based on the results obtained, we evaluated the validity of environmental indicator for ruderal and urban environments by the pair of native dandelions and tetraploid hybrids.

DOI： 10.5632/jila.69.545

記述言語：日本語  

高感度・高精度・迅速なシアナミド定量法

記述言語：日本語  

土壌中におけるL-DOPAの植物生育阻害活性の消長

記述言語：日本語  

アオコの増殖抑制植物を検定する「リーフディスク法」の開発

記述言語：英語   掲載種別：研究論文（その他学術会議資料等）  

There are two major strategies for isolation of bioactive natural products. One is to find compounds with high specific activity (biological activity per unit weight of the compound). This leads to the discovery of the most active compounds present in an organism with low EC₅₀ (effective concentration of the compound to induce half-maximum action). In the other strategy, compounds with high total activity (biological activity per unit weight of the organism containing the bioactive compound), causing a particular phenomenon, are isolated. In this strategy, EC₅₀ of the compound is not necessarily low. The total activity is determined by the specific activity and concentration (or content) of the compound in the organism, and this could explain the role and influence of the compound in the phenomenon. Differences between the two strategies and the importance of the choice for the right one to apply are emphasized, and applicatory examples complementary to each strategy are presented. The author proposes to use the terminology and concept of "total activity" and "specific activity" to avoid confusion in scientific discussions.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Replanting of asparagus (Asparagus officinalis L.) often results in lower yields and extensive damage of young plants. One of the causes is considered allelopathy. In this study, we examined the participation of allelopathy on injury by continuous cropping of asparagus in alluvial soil. The presence of strong allelochemical substances, which have the growth-inhibitory activity, was detected by bioassay of rhizosphere soil around asparagus. This growth-inhibitory activity was not attributed to salt accumulation, pH fluctuation, or inorganic nutrient imbalance in the rhizosphere soil. Asparagus foliage incorporated into the soil did not demonstrate a close relation to the growth inhibition or decreased yield of asparagus. However, strong growth-inhibitory activity was demonstrated in the storage roots of asparagus. It is assumed that an allelochemical is exuded from the storage roots and is one of the causes of unsuccessful continuous cropping of asparagus.

DOI： 10.2503/hrj.5.431

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

We developed a new method of examining the effects of allelochemical substances exuded from the roots of asparagus (Asparagus officinalis L.) to rhizosphere soil. This rhizosphere soil bioassay method provided results similar to those from the conventional bioassay method in which asparagus germinates in the soil. The new method was more effective than the conventional bioassay method because the soil samples could be tested using a smaller volume. This method could also evaluate flowable activated carbon as one of the materials to absorb allelochemical substances at a laboratory level. An appropriate orientation of cultivation is expected to become possible using the rhizosphere soil assay method developed in this study to examine obstructions to continuous cropping that may be related to allelopathy.

DOI： 10.2503/hrj.5.443

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

The growth-inhibitory activities of allelopathy in asparagus (Asparagus officinalis L.) was studied using the 'Plant Box Method' of bioassay. By this methods we confirmed that asparagus produced allelochemical substances. Then we developed a modified plant box method to examine the relationship between the growth-inhibitory activity and the adsorption of materials to allelochemical substances from asparagus. As a result, a type of activated carbon has the ability to absorb the allelochemical substances and prevent the growth inhibition of lettuce, an assay plant. Furthermore, in a field replanted with asparagus, treatment with activated carbon increased the fresh weights of rhizomes and storage roots, as well as the number of storage roots, the growth amount, and the growth index (GI'), when compared to those of asparagus grown on non-treated plots.

DOI： 10.2503/hrj.5.437

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Velvetbean (Mucuna pruriens) has been reported to release 3-(3′,4′-dihydroxyphenyl)-L-alanine (L-DOPA) as an allelochemical that inhibits the growth of other plants, although the inhibitory activity depends on the soil type and it is extremely reduced in Andosols. To clarify the effects of Andosols and their components on the chemical structure and plant-growth-inhibitory activity of L-DOPA, an L-DOPA solution was reacted with an Andosol and its components (weathered pumice and purified allophane), and the resultant solution was subjected to ¹H nuclear magnetic resonance and ultraviolet-visible spectral analyses, and plant-growth-inhibitory activity tests. When the L-DOPA solution was added to the soil components, the concentration of L-DOPA in the solution decreased by adsorption and transformation (polymerization) reactions. The adsorption mechanism included a ligand exchange reaction. The rate of L-DOPA transformation was faster at higher pH values. The soil components displayed a catalytic activity and accelerated the transformation of L-DOPA. Similar transformation occurred when light was irradiated. At pH values higher than 4.0, the transformed products from L-DOPA consisted of humic substances-like heterogeneous components, whereas specific components with low molecular weight were included when L-DOPA was transformed at a pH value of 9.7 or higher. The plant-growth-inhibitory activity of L-DOPA was extremely weakened when L-DOPA was adsorbed on or transformed (polymerized) by soil components. Therefore, in soils with high abilities of adsorption and transformation of L-DOPA such as in Andosols, it was likely that the L-DOPA concentration in the soil solution decreased quickly by adsorption and transformation reactions and the allelopathic activity of L-DOPA was lost.

DOI： 10.1111/j.1747-0765.2005.tb00055.x

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Allophanes are poorly crystalline and quasi-stable aluminosilicate minerals, the structures of which are sensitive to chemical treatment. In the present study, solid-state 27Al and 29Si nuclear magnetic resonance (NMR) spectra of allophane samples were monitored as they went through several purification procedures. It was confirmed that no significant structural changes were caused by boiling with 6&#37; H2O2 to remove organic matter, by size fractionation (sonification), by sedimentation, by precipitation at pH 4.0, or by dithionite-citrate-bicarbonate treatment for the removal of Fe (hydr)oxides. Hot 5&#37; Na2CO3 treatment for the removal of reactive silica-alumina gels and adsorbed citrate from allophane samples, however, decreased signal intensity corresponding to imogolite-like Si (Q33VIAl, -78 ppm in 29Si NMR) and increased signal intensities corresponding to IVAl (55 ppm in 27Al NMR) and possibly X-ray amorphous aluminosilicates (centered at -85 ppm in 29Si NMR). Cold (room temperature) 5&#37; Na2CO3 treatment for 16 h proved to be effective in avoiding these structural changes. Copyright © 2005, The Clay Minerals Society.

DOI： 10.1346/CCMN.2005.0530611

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Cyanamide is a multifunctional agrochemical used, for example, as a pesticide, herbicide, and fertilizer. Recent research has revealed that cyanamide is a natural product biosynthesized in a leguminous plant, hairy vetch (Vicia villosa). In the present study, gas chromatography-mass spectrometry (GC-MS) equipped with a capillary column for amines was used for direct quantitative determination of cyanamide. Quantitative signals for ( ¹⁴N₂)cyanamide, (¹⁵N₂)cyanamide (internal standard for stable isotope dilution method), and m-(trifluoromethyl) benzonitrile (internal standard for correcting errors in GC-MS analysis) were recorded as peak areas on mass chromatograms at m/z 42 (A₄₂), 44 (A₄₄), and 171 (A_IS), respectively. Total cyanamide content, (¹⁴N₂)cyanamide plus (¹⁵N ₂)cyanamide, was determined as a function of (A₄₂ + A ₄₄)/A_IS. Contents of (¹⁴N₂)cyanamide and (¹⁵N₂)cyanamide were then calculated by multiplying the total cyanamide content by A₄₂/(A₄₂ + A₄₄) and A₄₄/(A₄₂ + A₄₄), respectively. The limit of detection for the total cyanamide content by the GC-MS analysis was around 1 ng. The molar ratio of (¹⁴N₂)cyanamide to ( ¹⁵N₂)cyanamide in the injected sample was equal to the observed A₄₂/A₄₄ value in the range from 0.1 to 5. It was, therefore, possible to use the stable isotope dilution method to quantify the natural cyanamide content in samples; i.e., the natural cyanamide content was derived by subtracting the A₄₂/A₄₄ ratio of the internal standard from the A₄₂/A₄₄ ratio of sample spiked with internal standard, and then multiplying the resulting difference by the amount of added (¹⁵N₂)cyanamide (SID-GC-MS method). This method successfully gave a reasonable value for the natural cyanamide content in hairy vetch, concurring with the value obtained by a conventional method in which cyanamide was derivatized to a photometrically active compound 4-cyanimido-1,2-naphthoquinone and analyzed with reversed-phase HPLC (CNQ-HPLC method). The determination range of cyanamide in the SID-GC-MS method was almost the same as that in the CNQ-HPLC method; however, the SID-GC-MS method was much simpler than the CNQ-HPLC method.

DOI： 10.1016/j.chroma.2005.08.035

記述言語：英語   掲載種別：研究論文（学術雑誌）  

3-(3′,4′-Dihydroxyphenyl)-L-alanine (L-DOPA), which is a component of velvetbean (Mucuna pruriens), displays a high inhibitory activity to plant growth. The inhibitory activity is influenced by the presence of soils, because L-DOPA is eliminated in soils. In the present study, the effect of several soil types (volcanic ash, calcareous, and alluvial soils) on the L-DOPA disappearance was investigated at constant equilibrium pH values. In the presence of soils, L-DOPA disappeared with the reaction time, and the disappearance was associated with three reactions: adsorption reaction (characterized by fast and sudden disappearance of L-DOPA within the initial 8 h period), catalytic transformation reaction (constant L-DOPA disappearance throughout the reaction period), and biotransformation caused by microbial activity (accelerated L-DOPA disappearance observed after 72 h of reaction time). The adsorption and transformation reactions consisted of physicochemical reactions mediated by the presence of soils. The amount of L-DOPA adsorbed was largest in the presence of volcanic ash soil among the three soil types. It is likely that the mechanism of L-DOPA adsorption includes a ligand exchange reaction. In the presence of soils, L-DOPA transformation was observed at equilibrium pH values higher than 4 and it increased with increasing equilibrium pH values. In the absence of soil, however, L-DOPA transformation did not occur at an equilibrium pH value lower than 6.0, indicating that L-DOPA transformation was accelerated by the presence of soil. The rate of L-DOPA transformation mediated by soils at constant equilibrium pH value was in the following order: alluvial soil > calcareous soil > volcanic ash soil. The plant-growth-inhibitory activity of L-DOPA was also reduced by the presence of soils, and the reduction in the case of L-DOPA was more obvious than in the case of 2,4-dichlorophenoxyacetic acid (2,4-D). Based on the reduction effect of soils on the plant-growth-inhibitory activity of L-DOPA (without pH-adjustment), calcareous soil ranked first, followed by volcanic ash soil, then alluvial soil. This was because the calcareous soil showed the highest soil pH value (7.8), and thereby the L-DOPA transformation reaction was accelerated. In soils with high pH values, the plant-growth-inhibitory activity of L-DOPA could therefore not be detected.

DOI： 10.1111/j.1747-0765.2005.tb00116.x

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

PA-09 Community structure of bacteria inhabiting wheat heads and their production of quorum sensing-related signal molecules(AGRICULTURAL SOIL ECOSYSTEM,Session A,(1) Poster presentations)

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Robinia pseudo-acacia L. (black locust) is a nonindigenous species currently invading the central part of Japanese grasslands. Several allelochemicals were identified and characterized from the leaf tissue. The growth of both radicle and hypocotyl in the tested species (barnyard grass, white clover, lettuce, and Chinese cabbage) was reduced when grown in soil mixed with the leaves of R. pseudo-acacia at various concentrations. Aqueous leaf extracts, when bioassayed, exhibited a significant suppression of radicle growth. Chromatographic separation of an ethanolic extract of R. pseudo-acacia leaves resulted in isolation of three compounds, identified as robinetin (1), myricetin (2), and quercetin (3) by nuclear magnetic resonance and mass spectroscopy. All inhibited root and shoot growth of lettuce. Robinetin, found in a large amount, caused 50% suppression of the root and shoot growth of lettuce at 100 ppm. The presence of these bioactive substances in leaf tissue suggests a potential role for flavonoids in R. pseudo-acacia invasion in introduced habitats.

DOI： 10.1007/s10886-005-6084-5

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Screening of allelopathic activity from rice cultivars by bioassay and field test.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Rhizosphere soil method: a new bioassay to evaluate allelopathy in the field

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Dish pack method: a new bioassay for volatile allelopathy.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A critical survey of allelochemicals in action: the importance of total activity and the weed suppression equation,

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To clarify the weathering process of volcanic glass to allophane, solid-state ²⁹Si and ²⁷Al magic angle spinning (MAS) nuclear magnetic resonance (NMR) signals of four Japanese volcanic glasses and two (Al- and Si-rich) allophanes were assigned. The volcanic glasses showed a broad ²⁹Si NMR signal between -80 and -120 ppm with the peak centered at ∼ -104 ppm, indicating that they were rich in Si-O-Si bridging structure (silica gel-like polymer Si). Aluminum was present in tetrahedral form in the four volcanic glass samples. In both Al- and Si-rich allophanes, octahedral Al (3 ppm by ²⁷ Al NMR) and imogol ite-like Si (Q³3^VIAl, -78 ppm by ²⁹Si NMR) were the major components. In a Si-rich allophane, NMR signals centered at around -85 ppm for ²⁹ Si and 55 ppm for ²⁷ Al were also observed, although it is possible that those signals were derived from impurities. Impurities could have originated from the soils and/or been unexpectedly synthesized during the purification procedures, e.g. during hot 2% Na₂CO₃ treatments. Based on the NMR spectra of size-fractionated soil samples, the weathering process of volcanic glass to allophane was proposed as follows: (1) dissolution of Al from volcanic glass accompanied by the transformation of ^IVAl to ^VIAl; (2) formation of a gibbsite-like sheet resulting from the hydrolysis of the dissolved A1; (3) dissolution of silica gel-like polymer Si in volcanic glass resulting in the formation of monosilicic acid; and (4) formation of Si(OH)(O^VIAl)₃ structure (Q³3^VIAl) as a result of the reaction between the gibbsite-like sheet and the monosilicic acid. These formation reactions of allophane could occur in solution as well as on the surface of volcanic glass.

DOI： 10.1346/CCMN.2005.0530408

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Myrothecium verrucaria infects various plants, but the mechanism of infection is unknown. We studied infection of using M. verrucaria strain MAFF840074, that causes Myrothecium leaf spot of mulberry, to mulberry leaves. Infection by conidia washed with water was low, and an extract of the fungal culture grown on potato sucrose agar caused necroses of the leaves. Infection by conidia was high and the diameter of the resulting lesions was larger if the extract was added to the conidia at the time of inoculation. Roridin A, verrucarins A and J, and an unidentified toxic substance (toxic substance A) were isolated from the extract based on induction of necroses on mulberry leaves using high performance liquid chromatography (HPLC). Roridin A and verrucarin J were more toxic to mulberry leaves than verrucarin A and the toxic substance A. The toxicity of each substance tended to be higher on sensitive mulberry cultivars than on cultivars resistant to the disease. Toxic substances with the same Rf value as roridin A, verrucarin A and the toxic substance A using thin layer chromatography were detected from extracts of mulberry leaves after inoculation with the fungus. With HPLC, the substances in the extract and concentrations of them were determined to be highest (roridin A : 5×10^<-7>M, verrucarin A : 1.6×10^<-7>M and the toxic substance A : 21×10^<-7>M) at 12 days after the inoculation during the 14-d period. However, verrucarian J was not detected from the extract by the methods. Washed conidia of the fungus did not infect mulberry leaves (cv. Shin Ichinose) but infect the leaves when roridin A or verrucarin A at concentration that they caused necroces to the leaves or higher were added at the time of inoculation. Therefore, the results suggested that roridin A, verrucarin A and the toxic substance A might play some roles in the pathogenicity of the fungus.

記述言語：日本語  

ムクナの根から放出されるL-ドーパに対する植物の抵抗性機構

記述言語：日本語  

日本在来の被覆植物リュウノヒゲの他感作用と他感物質としてのサリチル酸の発見

記述言語：日本語  

外来植物ニセアカシアのアレロパシー活性と作用物質

記述言語：日本語  

ユキヤナギに含まれる高活性植物生育阻害物質の発見

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Crude extracts of the leaves of Spiraea prunifolia Sieb. showed high plant-growth-inhibiting activity comparable to that of S. thunbergii extracts. To isolate the causal compound in S. prunifolia, we performed bioassay-directed purification by monitoring the biological activity per unit weight of the organism containing the bioactive compound (total activity). We isolated 1-O-cis-cinnamoyl-β-D-glucopyranose (cis-CG) and identified it as the most important growth-inhibiting constituent in the crude extracts. We did not detect 6-O-(4′-hydroxy-2′-methylenebutyroyl)-1-O-cis-cinnamoyl-β-D- glucopyranose (cis-BCG) in S. prunifolia, though it is a major plant growth inhibitor in S. thunbergii together with cis-CG. We estimated the cis-CG content in S. prunifolia to be 3.84 mmol kg^-1 F.W. This amount is comparable to the cis-CG plus cis-BCG content in S. thunbergii (3.59 mmol kg^-1 F.W.). This indicates that S. prunifolia and S. thunbergii have equally high potential to inhibit plant growth, and cis-CG acts as the most important plant-growth inhibitor in S. prunifolia extracts.

DOI： 10.1007/s10725-005-8086-2

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Two distinct electroantennographycally active (EAG-active) components, A and B, and a weakly active component C were found in a solvent extract from virgin females of the Ishigaki strain of the tussock moth, Orgyia postica (Walker). Components A, B, and C were found in the extract of the females at 4.0, 0.5, and 4.0 ng/female respectively. Components A, B, and C were identified as (6Z,9Z,11S,12S)-11,12-epoxyhenicosa-6,9-diene [(11S,12S)-1: posticlure], (6Z)-henicos-6-en-11-one (2), and (6Z,9Z)-henicosa-6,9-diene (3), respectively. Component B was absent in the extract from the Okinawa strain, in which components A and C were present at 2.0 and 1.5 ng/female respectively. (11S,12S)-1 and the racemic mixture showed attractiveness for both the Okinawa and Ishigaki strains, whereas (11R,12R)-1 did not. The addition of 2 significantly reduced the trap catches with (11S,12S)-1 on the Okinawa strain which lacked 2, while there was no significant inhibitory effect on the Ishigaki strain. The addition of 3 to (11S,12S)-1 did not significantly affect trap catches at Ishigaki or Okinawa. This confirmed that the attractant pheromone of O. postica of the Ishigaki strain is also (11S,12S)-1.

DOI： 10.1271/bbb.69.957

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Spiraea thunbergii Sieb. contains 1-O-cis-cinnamoyl-β-D-glucopyranose (CG) and 6-O-(4′-hydroxy-2′-methylene-butyroyl)-1-O-cis-cinnamoyl- β-D-glucopyranose (BCG) as major plant growth inhibiting constituents. In the present study, we determined the inhibitory activity of CG and BCG on root elongation of germinated seedlings of lettuce (Lactuca sativa), pigweed (Amaranthus retroflexus), red clover (Trifolium pratense), timothy (Phleum pratense), and bok choy (Brassica rapa var chinensis) in comparison with that of two well-known growth inhibitors, 2,4-dichlorophenoxyacetic acid (2,4-D) and (+)-2-cis-4-trans-abscisic acid (cis-ABA), as well as two related chemicals of CG and BCG, cis-cinnamic acid (cis-CA) and trans-cinnamic acid (trans-CA). The EC₅₀ values for CG and BCG on lettuce were roughly one-half to one-quarter of the value for cis-ABA. cis-Cinnamic acid, which is a component of CG and BCG, possessed almost the same inhibitory activity of CG and BCG, suggesting that the essential chemical structure responsible for the inhibitory activity of CG and BCG is cis-CA. The cis-stereochemistry of the methylene moiety is apparently needed for high inhibitory activity, as trans-CA had an EC₅₀ value roughly 100 times that of CG, BCG, and cis-CA. Growth inhibition by CG, BCG, and cis-CA was influenced by the nature of the soil in the growing medium: alluvial soil preserved the bioactivity, whereas volcanic ash and calcareous soils inhibited bioactivity. These findings indicate a potential role of cis-CA and its glucosides as allelochemicals for use as plant growth regulators in agricultural fields.

DOI： 10.1007/s10886-005-2047-0

記述言語：日本語  

間伐材から抽出された植物生育促進物質1,2-プロパンジオール

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To gain a better understanding about the δ¹³C values of organic constituents and possible source of humic substances in Japanese volcanic ash soils, we determined the δ¹³C values of charred plant fragments, humic and fulvic acids, and whole soils, using 10 volcanic ash soil samples. Furthermore, the characteristics of the humic acid obtained from the dil. H₂O₂-treated residues of charred plant materials, which were produced during the burning of a grassland, were compared with those of black (type A) humic acids in volcanic ash soils. The δ¹³C values of the charred plant fragments, humic and fulvic acids, and whole soils studied ranged from -25 to -17‰, -25 to -17‰, -23 to -15‰, and -24 to -17‰, respectively. The δ¹³C values of the whole soils were highly correlated with those of the charred plant fragments (r = 0.968, significant at 0.1% level), humic acids (r = 0.947, significant at 0.1% level) or fulvic acids (r = 0.900, significant at 0.1% level), suggesting that in Japanese volcanic ash soils, the δ¹³C data of whole soils are valuable for discussing and estimating the origin of carbon of charred plant fragments as well as humic and fulvic acids. The δ¹³C values of the charred plant fragments were highly correlated with those of the fulvic acids (r = 0.792, significant at 1% level) and especially humic acids (r = 0.951, significant at 0.1% level). The contribution ratios of C4-plant-derived carbon on the carbon in the charred plant fragments, humic and fulvic acids, and whole soils ranged from 15 to 69%, 16 to 65%, 29 to 86%, and 24 to 66%, respectively. The ¹³C-NMR spectrum and X-ray diffraction pattern of the humic acid obtained from the oxidative degradation products of the charred plant materials were similar to those of type A humic acids reported previously. Based on these findings, it was assumed that both charred C3- and C4-plant materials merit close attention as an important source of humic substances in Japanese volcanic ash soils.

DOI： 10.1097/01.ss.0000160033.45802.2c

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The PCS (commercial products by Field Science Co, Japan, used for air fresheners) was analyzed for the presence of bioactive constituents and their role as root growth promoters. Chromatographic separation of the methanolic solution of PCS resulted in the isolation of an promoting active substance, which was identified using GC-mass spectrometry and NMR spectroscopy as 1,2-propanediol (CH₃CH(OH)CH₂OH). Lettuce seedling growth bioassay as test plant revealed that 1,2-propanediol can act as potent root growth promoter; enhancing the growth of lettuce seedling radicle at a concentration 0.01 ppm. The concentration of 1,2-propanediol in PCS mixture was estimated as 4 g/l. These studies suggest that 1,2-propanediol might play an important role in the plant growth promoting activity of PCS.

DOI： 10.1007/s10725-004-7087-x

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Myrothecium verrucaria infects various plants, but the mechanism of infection is unknown. We studied infection of using M. verrucaria strain MAFF840074, that causes Myrothecium leaf spot of mulberry, to mulberry leaves. Infection by conidia washed with water was low, and an extract of the fungal culture grown on potato sucrose agar caused necroses of the leaves. Infection by conidia was high and the diameter of the resulting lesions was larger if the extract was added to the conidia at the time of inoculation. Roridin A, verrucarins A and J, and an unidentified toxic substance (toxic substance A) were isolated from the extract based on induction of necroses on mulberry leaves using high performance liquid chromatography (HPLC). Roridin A and verrucarin J were more toxic to mulberry leaves than verrucarin A and the toxic substance A. The toxicity of each substance tended to be higher on sensitive mulberry cultivars than on cultivars resistant to the disease. Toxic substances with the same Rf value as roridin A, verrucarin A and the toxic substance A using thin layer chromatography were detected from extracts of mulberry leaves after inoculation with the fungus. With HPLC, the substances in the extract and concentrations of them were determined to be highest (roridin A: 5×10^-7M, verrucarin A: 1.6×10^-7M and the toxic substance A: 21×10^-7M) at 12 days after the inoculation during the 14-d period. However, verrucarian J was not detected from the extract by the methods. Washed conidia of the fungus did not infect mulberry leaves (cv. Shin Ichinose) but infect the leaves when roridin A or verrucarin A at concentration that they caused necroces to the leaves or higher were added at the time of inoculation. Therefore, the results suggested that roridin A, verrucarin A and the toxic substance A might play some roles in the pathogenicity of the fungus.

DOI： 10.3186/jjphytopath.71.166

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Allelopathic potential of Ophiopogon japonicus was investigated. The methanolic extract of O. japonicus roots strongly inhibited root and hypocotyls growth of lettuce. Sequential partitioning of the methanol extract with organic solvents showed that the diethyl ether and n-butanol extract possess strong plant growth inhibitory activities. The allelopathic constituents of the diethyl ether extract were isolated and identified as salicylic acid and p-hydroxybenzoic acid by NMR spectroscopy. Both of these phenolic acids were found in the aqueous extracts of leaves as well. The concentration of salicylic acid in roots and leaves were estimated as 0.011 and 0.02%, respectively, and it inhibited the root and shoot of tested plants by 50% even at less than 3 ppm. The p-hydroxybenzoic acid on the other hand was in less abundance (0.005%) and inhibited the plant growth to a lesser extent. The biological activity of commercially available O-methyl derivatives of these phenolic acids was also determined to establish structure-activity relationship. Among these, salicylic acid was found to be the most active one. These results suggest that Ophiopogon japonicus produces plant growth inhibitors, which are responsible for its potential allelopathic activity.

DOI： 10.1023/B:GROW.0000045998.68084.4b

記述言語：日本語  

根圏土壌を用いた他感作用検定手法の開発

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We investigated the influences of humic acid on the removal of Al tridecamer (Al₁₃) from a hydroxyaluminum (HyA) solution at various humic acid/Al ratios. The Al species contained in the solution were analyzed by using a liquid-state ²⁷Al-NMR and an atomic absorption spectrometer and fractionated into three Al species: (i) Al₁₃, (ii) Al monomer and dimer (Al_SYM), and (iii) other undefined species including aggregated/precipitated Al (Al_NON). By the addition of humic acid to the HyA solution, the concentration of Al₁₃ was rapidly decreased within 0.007 d (10 min). The decrease in Al₁₃ and the increase in Al_NON were more pronounced at a higher humic acid/Al ratio. When the molar ratio of humic acid carboxylic groups to Al exceeded 0.8, Al₁₃ was undetected from solution within 0.007 d. The formation of Al ₁₃-humic acid complexes and the aggregation/precipitation of those complexes were a predominant mechanism in removing aqueous Al₁₃ at the early stage of the reaction. Approximately 10 mol of carboxylic groups in humic acid were required to remove 1 mol of Al₁₃ from the HyA solution. Aqueous Al₁₃ had greater preference in precipitating with humic acid than Al_SYM. After 5 to 570 d of aging, the concentration of Al₁₃ and Al_NON also decreased and increased, respectively, both in the presence and absence of humic acid. In conclusion, aqueous Al₁₃ would not exist in soil solution under a high humic acid condition.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Allelopathic activity of 4 different types of weeds-Japanese native weeds (38 species of 18 families) , naturalized or established weeds in Japan (30 species of 12 families), newly imported weeds (18 species of 8 families, originating as feed-mix in imported feeds), and Brazilian weeds (55 species of 17 families, considered potentially invasive) , and total 129 species of 25 families were evaluated by "Plant-Box" method using lettuce as a test plant. Results showed that the imported weeds had not always lower allelopathic activity than that of naturalized or established ones. However, several Brazilian weeds showed high allelopathic activities in comparison to native, naturalized or established weeds. The velvetleaf (either the imported or endemic type) showed strong phytotoxic effect against lettuce radicle growth. In case of common lambsquarters, strong allelopathic activities were observed on the imported type and that with Brazilian origin, but allelopathic activity of those phenotypes that already established in Japan was not prominent. These results suggest that allelopathic activity might depend on their origin of each phenotype. This study suggests that some potentially invasive weeds, as well as some imported weeds, were highly allelopathic, and could possibly become a threat to Japanese vegetation, if they invade, and establish in Japan.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In order to elucidate the allelopathic effect of leaf litter leachates under laboratory conditions, a modified 'sandwich method', which places leaves between two layers of agar, was used. Fifty mg of leaves was used per 10 cm ² cell. Agar concentrations at 0.5-1.0% were the best for gel support in determining radicle and hypocotyl elongation of lettuce. The optimum incubation time for bioassay was three days after imbibition onset. Among 20 typical tree species in Asia, Cymbopogon citratus and Derris scandens showed the strongest inhibitory activity determined by the sandwich method, followed by Piper betle, Tamarindus indica, and Gliricidia sepium. This bioassay seems to be a reliable method for screening allelopathic activity from leaf litter leachates.

DOI： 10.1111/j.1445-6664.2003.00113.x

記述言語：英語  

Role of allelopathy in invasion of an exotic plant Robinia pseudo-acacia L.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

トリュフ(Tuber melanosporum)は子実体が発生する条件が整うとその地上部には"ブリュレ(焼け跡地)"と呼ばれる草の生えないパッチが観察されるようになる。同様の抑草現象は野生種のハナホウキタケ、ニンギョウタケなどにも観察され、化学物質を放出することにより現象を発現していることが考えられる。しかし、キノコのアレロパシーを利用した雑草抑制の試みはほとんどなされておらず、作用成分もほとんど明らかにされていない。そこで、キノコ子実体のアレロパシー活性を昨年に引き続きサンドイッチ法を用いて検定した。また、サンドイッチ法により、活性が強かったブナシメジ(Hipsizigus marmoreus)については、菌体が多く含まれる廃菌床についても成長阻害活性を調査した。

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Plant growth inhibitory alkaloids were isolated from the extract of mesquite [Prosopis juliflora (Sw.) DC.] leaves. Their chemical structures were established by ESI-MS, ¹H and ¹³C NMR spectra analysis. The I₅₀ value (concentration required for 50% inhibition of control) for root growth of cress (Lepidium sativum L.) seedlings was 400 μM for 3″″-oxo-juliprosopine, 500 μM for secojuliprosopinal, and 100 μM for a (1:1) mixture of 3-oxo-juliprosine and 3′-oxo-juliprosine, respectively. On the other hand, the minimum concentration exhibiting inhibitory effect on shoot growth of cress seedlings was 10 μM for 3″″-oxo-juliprosopine, 100 μM for secojuliprosopinal, and 1 μM for a (1:1) mixture of 3-oxo-juliprosine and 3′-oxo-juliprosine, respectively. Among these compounds, a (1:1) mixture of 3-oxo-juliprosine and 3′-oxo-juliprosine exhibited the strongest inhibitory effect on the growth of cress seedlings.

DOI： 10.1016/j.phytochem.2004.01.006

記述言語：日本語  

土壌を用いた他感作用の検定手法の開発

記述言語：日本語  

ソバ属植物のアレロパシーとソバを利用した植生管理

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Spiraea thunbergii Sieb. was found to contain 1-O-cis-cinnamoyl-β-D- glucopyranose and 6-O-(4′-hydroxy-2′-methylene-butyroyl)-1-O-cis- cinnamoyl-β-D-glucopyranose as major plant growth inhibitory constituents along with related compounds of lower phytotoxicity including 6-O-(trans-cinnamoyl)-1-O-(4″-hydroxy-3″-methyl-furan-2″-one) -β-D-glucopyranose, 6-O-(4′-hydroxy-2′-methylene-butyroyl)-1-O- trans-cinnamoyl-β-D-glucopyranose, and 1-O-trans-cinnamoyl-β-D- glucopyranose. The former three compounds were cinnamoyl glucosides.

DOI： 10.1016/j.phytochem.2004.01.010

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Effects of soil organic matter (80M) on P sorption of soils still remain to be clarified because contradictory results have been reported in the literature. In the present study, pH-dependent P sorption on an allophanic Andisol and an alluvial soil was compared with that on hydrogen peroxide (H₂0₂)-treated, acid-oxalate (OX)-treated, and dithionite-citrate- bicarbonate (DCB)-treated soils. Removal of 80M increased or decreased P sorption depending on the equilibrium pH values and soil types. In the H₂O₂ OX-, and DCB-treated soils, P sorption was pH-dependent, but this trend was not conspicuous in the untreated soils. It is likely that 80M affects P sorption of soils through three factors, competitive sorption, inhibition of polymerization and crystallization of metals such as AI and Fe, and flexible structure of metal-80M complexes. As a result, the number of available sites for P sorption would remain relatively constant in the wide range of equilibrium pH values in the presence of 80M. The P sorption characteristics were analyzed at constant equilibrium pH values (4.0 to 7.0) using the Langmuir equation as a local isotherm. The maximum number of available sites for P sorption (Q_max) was pH-dependent in the H₂0₂-, OX-, and DCBtreated soils, while this trend was not conspicuous in the untreated soils. Affinity constants related to binding strength (K) were less affected by the equilibrium pH values, soil types, and soil treatments, and were almost constant (log K ≈ 4.5). These findings support the hypothesis that 80M plays a role in keeping the number of available sites for P sorption relatively constant but does not affect the P sorption affinity. By estimating the Q_max and K values as a function of equilibrium pH values, pH-dependent P sorption was well simulated with four or two adjustable parameters. This empirical model could be useful and convenient for a rough estimation of the pH-dependent P sorption of soils.

DOI： 10.1080/00380768.2004.10408523

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Although aluminum (Al) is abundant in soil environments, it is not an essential element and it is toxic to most organisms. Since the toxicity of Al depends on their chemical forms, the importance of Al speciation has been recognized worldwide. Difficulties in Al speciation are caused by the complex coordination chemistry of Al for the hydrolysis and formation of polynuclear species with a variable degree of solubility in aqueous solution. Nondestructive analyses, such as nuclear magnetic resonance (NMR) spectroscopy, could supply primarily im-portant information on the chemical forms of Al and may enable to evaluate the results ob-tained by other methodologies. In the present report, NMR spectral characteristics of environmentally important Al-containing components, such as hydoxyaluminum ions, Alinorganic complexes, Al-organic complexes, and primary and secondary minerals, are summarized for the nuclei of ²⁷Al and ²⁹Si determined by solution NMR and solid-state magic angle spinning (MAS) NMR. Applications of NMR techniques to soil science, including speciation of phytotoxic Al in soil environments and whole soil NMR studies, are described.

DOI： 10.1080/00380768.2004.10408483

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Volcanic ash soils (including Andisols) have been known to accumulate extremely large amounts of humic acids in their thick surface horizons, and their accumulation mechanism is of interest. Two mechanisms have been proposed: (1) active metals like Al and Fe, supplied from weathered volcanic materials, stabilize humic acids through complexation reactions; (2) cultivated Japanese pampas grasses (Miscanthus sinensis A.) and its charred materials are the major carbon source of humic acids. In the present study, contribution ratio of the pampas grass (C4-plant) on the carbons of the humic acids was determined by measuring their stable isotopic ratio of carbon (δ¹³C). In Japanese volcanic ash soils, humic acids were originated from both C3- and C4-plants, and the contribution ratio of C4-plants (mostly pampas grass) ranged from 18% to 52%. Highly humified (dark-colored) humic acids tended to show higher contribution ratio of C4-plants among volcanic ash soils, although the major part of the carbon had originated from C3-plants. It was also clarified that the δ¹³C values of crude soil samples correlated well with those of humic and fulvic acids. Therefore, reported δ¹³C values of crude soil samples in the literature would be useful for estimating the carbon source of soil humic substances. Literature survey of the δ¹³C values of crude soil samples also indicated that a large part of the carbon in humic substances has originated from C3-plants rather than C4-plants, implying the importance of the active metals (such as Al and Fe) on the formation and accumulation of the humic acids in volcanic ash soils.

DOI： 10.1016/S0016-7061(03)00257-X

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Allelopathic activity of 4 different types of weeds-Japanese native weeds (38 species of 18 families), naturalized or established weeds in Japan (30 species of 12 families), newly imported weeds (18 species of 8 families, originating as feed-mix in imported feeds), and Brazilian weeds (55 species of 17 families, considered potentially invasive), and total 129 species of 25 families were evaluated by "Plant-Box" method using lettuce as a test plant.
Results showed that the imported weeds had not always lower allelopathic activity than that of naturalized or established ones. However, several Brazilian weeds showed high allelopathic activities in comparison to native, naturalized or established weeds. The velvetleaf (either the imported or endemic type) showed strong phytotoxic effect against lettuce radicle growth. In case of common lambsquarters, strong allelopathic activities were observed on the imported type and that with Brazilian origin, but allelopathic activity of those phenotypes that already established in Japan was not prominent. These results suggest that allelopathic activity might depend on their origin of each phenotype. This study suggests that some potentially invasive weeds, as well as some imported weeds, were highly allelopathic, and could possibly become a threat to Japanese vegetation, if they invade, and establish in Japan.

DOI： 10.3719/weed.49.169

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Allelopathy of fruiting bodies of higher fungi

DOI： 10.3719/weed.49.Supplement_176

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A sex pheromone component of Pseudococcus cryptus has been isolated and identified. The crude pheromone extract obtained by airborne collection was fractionated by liquid chromatography (LC) on Florisil, and further purified by high performance liquid chromatography and preparative Gas Chromatography (GC). The pheromone component was shown to be an ester, the alcohol part of which was identical to the known alcohol moiety of the pheromone of Planococcus citri. The chemical structure was determined to be 3-isopropenyl-2,2-dimethylcyclobutylmethyl 3-methyl-3-butenoate by MS and ¹H NMR analyses. The absolute configuration of the pheromone was assigned as (1R,3R) by comparison of the retention time of the alcohol derived from the P. cryptus pheromone with those of the alcohol derived from P. citri pheromone, and a synthetic sample of alcohol enriched in the (1R,3R)-enantiomer, using a chiral GC stationary phase. The structure of the pheromone was confirmed by synthesis, and by bioassays in a glasshouse.

DOI： 10.1023/A:1026214112242

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The formation and presence of aluminum tridecamer (Al₁₃, [AlO₄Al₁₂(OH)₂₄(H₂O) ₁₂]⁷⁺) in solution was strongly inhibited by soil humic acids (HA), as shown by liquid-state ²⁷Al-nuclear magnetic resonance (NMR) analyses. It was also observed that Al₁₃ coprecipitated with HA in the form of Al₁₃-HA complexes, as shown by solid-state magic angle spinning (MAS) ²⁷Al-NMR analyses. Tetrahedral Al in the Al ₁₃-HA complexes was gradually converted to octahedral Al, indicating that Al₁₃ in Al₁₃-HA complexes was decomposed into Al-HA complexes with reaction time. When HA was present in the acidic Al solution before the partial neutralization, the precipitates formed after the partial neutralization did not contain any tetrahedral Al, indicating the absence of Al₁₃ and that HA is a strong inhibitor of Al₁₃ formation. These results indicate that Al₁₃ is not formed from Al complexed with soil HA after partial neutralization. If Al₁₃ was added to soils, it would preferentially form precipitates of non-phytotoxic Al ₁₃-HA complex in the presence of excess HA (i.e. a COOH/Al ₁₃ molar ratio of more than 9) and gradually be converted to an octahedral Al-HA complex. Therefore, Al₁₃ is not a major plant-growth inhibitor in humus-rich acidic soils.

DOI： 10.1016/S0162-0134(03)00242-3

記述言語：英語  

Allelopathic flavonoids from buckwheat (Fagopyrum tartaricum Gaertn.)

記述言語：英語  

Plant growth inhibitory activity of triterpenoidal constituents of Ophiopogon japonics Ker-Gawl.

DOI： 10.3719/weed.48.Supplement_156

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Cyanamide was isolated from the leaves and stems of hairy vetch (Vicia villosa), guided by plant growth inhibitory activity against lettuce (Lectuca sativa) seedlings. A large proportion of the inhibitory activity in the crude extract was explained by the presence of cyanamide, suggesting it to be a possible allelochemical in this species. The amount in a 9-day-old seedling, which had been grown without nutrients, reached approx. 40 times that of a nongerminated seed. demonstrating cyanamide biosynthesis in the seedlings. This is the first report on the isolation of a possible allelochemical from hairy vetch and also of the finding of cyanamide as a natural product.

DOI： 10.1023/A:1022621709486

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Formation and disappearance of phytotoxic Al tridecamer (Al₁₃) in the rhizosphere can be affected by root exudates such as organic ligands. We investigated the effects of organic ligands on the formation and disappearance of Alla as a function of pH and COOH / Al ratio. The aqueous Al species were analyzed by using a liquid state²⁷Al-NMR and an atomic absorption spectrometer and separated into four fractions, as follows; 1) Al₁₃, 2) Al monomer and dimer (Al_SYM), 3) Al complexed with organic ligands (Al_ORG), and 4) other undefined species (Al_NON). Formation of Al₁₃ was suppressed by acetate, oxalate, and citrate. In addition, Al₁₃ that preexisted in a hydroxyaluminmn solution was disappeared by the introduction of acetate, oxalate, and citrate. Decrease in the concentration of Al₁₃ at the early stage of the reaction was caused by the decomposition of Al₁₃ along with the increase in the concentrations of Al_SYM and Al_ORG. After 7 d of reaction, it was likely that Al₁₃ was transformed into Al(OH)₃⁰ and other undefined species that could not be detected by²⁷Al-NMR. The ability of the carboxylic groups to suppress the occurrence of Al₁₃ (molar-basis) was in the order of acetate << oxalate < citrate, corresponding to the ability of complexation with Al. In conclusion, the phytotoxic effects of Al₁₃ were less pronounced because of the ubiquitous presence of organic ligands in the rhizosphere.

DOI： 10.1080/00380768.2003.10410044

記述言語：日本語  

ヘアリーベッチの他感作用と作用物質シアナミドの同定

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Laboratory and field experiments were conducted to assess the allelopathic potential of buckwheat. In the field, buckwheat demonstrated strong inhibitory activity by suppressing weeds. In laboratory studies, aqueous and organic solvent extracts of the aerial parts of common buckwheat inhibited the root and shoot growth of lettuce seedlings. The chloroform and ethyl acetate extracts showed maximum activity, and plants grown in the presence of the ethyl acetate extract showed severe root browning. The allelopathic constituents of the ethyl acetate phase were isolated and identified as gallic acid and (+)-catechin by nuclear magnetic resonance spectroscopy. Gallic acid and (+)-catechin were present in the upper part of buckwheat at concentrations of 0.02 and 0.01%, of fresh weight, respectively. Gallic acid was found to be selectively and strongly inhibitory to root and shoot growth of tested plants at 100 and 10 μg ml^-1. (+)-Catechin, however, inhibited plant growth to a lesser extent. These results suggest that buckwheat may have allelopathic potential and that when used as a ground cover crop or green manure may produce inhibitors, which could suppress weeds.

DOI： 10.1614/0043-1745(2003)051[0657:AAOBIA]2.0.CO;2

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Bacillus amyloliquefaciens strain RC-2 produced seven antifungal compounds (1-7) secreted into the culture filtrate. These compounds inhibited the development of mulberry anthracnose caused by the fungus, Colletotrichum dematium. Chemical structural analyses by NMR and FAB-MS revealed that all these compounds were iturins (cyclic peptides with the following sequence: L-Asn → D-Tyr → D-Asn → L-Gln → L-Pro → D-Asn → L-Ser → D-β-amino acid →) and compounds 1-6 are identical to iturins A-2-A-7, respectively. Compound 7 (iturin A-8) is a new iturin, which has a -(CH₂)₁₀CH(CH₃)CH₂CH₃ group as a side chain in the β-amino acid in the molecule.

DOI： 10.1016/S0031-9422(02)00365-5

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Bacillus amyloliquefaciens strain RC-2 produced seven antifungal compounds (1-7) secreted into the culture filtrate. These compounds inhibited the development of mulberry anthracnose caused by the fungus, Colletotrichum dematium. Chemical structural analyses by NMR and FAB-MS revealed that all these compounds were iturins (cyclic peptides with the following sequence: L-Asn --> D-Tyr --> D-Asn --> L-Gln --> L-Pro --> D-Asn --> L-Ser --> D-beta-amino acid -->) and compounds 1-6 are identical to iturins A-2-A-7, respectively. Compound 7 (iturin A-8) is a new iturin, which has a -(CH2)(10)CH(CH3)CH2CH3 group as a side chain in the beta-amino acid in the molecule. (C) 2002 Elsevier Science Ltd. All rights reserved.

記述言語：日本語  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Recent Advances in Soil Acidity and Problems to be Solved

記述言語：日本語  

ヘアリーベッチに含まれる植物生長阻害物質シアナミドの発見

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The absolute configurations of 2-methoxy-2-(1-naphthyl)propionic acid and 2-methoxy-2-(2-naphthyl)propionic acid were reconfirmed by NMR analyses of phenylglycine methyl ester (PGME) derivatives. Their absolute configurations determined by the PGME method are consistent with those obtained by the ¹H NMR anisotropy method and X-ray crystallography.

DOI： 10.1016/S0957-4166(02)00268-9

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To develop effective control techniques against mulberry anthracnose caused by Colletotrichum dematium, ecological and biocontrol studies on the disease were carried out. It was confirmed that the causal fungus overwinters mainly in infected mulberry leaves on the ground, then first infects the leaves adjacent to the ground in the rainy season. The fungal infection secondarily reaches the middle and upper foliage of mulberry trees with the passage of time, being less associated with the leaf age. The diseased leaves subsequently fall in autumn, and the fungus overwinters in these leaves again. It was suggested that the removal of fallen leaves from the mulberry field in autumn may contribute to cutting off the above disease cycle efficiently. A potential antagonist, Bacillus amyloliquefaciens strain RC-2, was isolated from healthy mulberry leaves. The antagonism was due to the production of antifungal compounds by the strain. Seven kinds of antifungal compounds were purified, and one of these was identified as iturin A2. Based on antagonistic mechanisms of the strain, the inhibition ability of RC-2 could be efficiently used by the application of the strain onto the leaves adjacent to the ground when primary fungal transmission from soil occurs. Furthermore, the antibiotics inhibited several other phytopathogenic fungi and bacteria, besides C. dematium, in vitro, suggesting that the antibiotics produced by RC-2 might be useful as multiple control materials against various plant diseases.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The allelopathic potential of buckwheat (Fagopyrum esculentum) was investigated. Field study showed that living buckwheat reduced weed biomass compared with plots without buckwheat. Laboratory study revealed that root exudates suppressed root and shoot growth of weeds and reduced weed dry weight. Sequential partitioning of the aqueous ethanolic extract of the aerial parts of buckwheat showed that the chloroform extract caused an 80% reduction in radicle elongation of lettuce seedlings at a concentration of less than 100 p.p.m. Fagomine, 4-piperidone and 2-piperidinemethanol were isolated and identified by ¹H and ¹³C nuclear magnetic resonance from the chloroform extract. These compounds caused a 50% inhibition of radicle elongation in lettuce seedlings at concentrations of less than 100 p.p.m. These results suggest that compounds 1, 2, and 3 might act as allelochemicals and affect the growth or germination of different plant species.

DOI： 10.1046/j.1445-6664.2002.00055.x

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Soil Components in Molecular Level and Nano-Scale Interactions among the Components

記述言語：日本語  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A potential antagonist, Bacillus amyloliquefaciens strain RC-2, against Colletotrichum dematium, mulberry anthracnose fungus, was obtained from healthy mulberry leaves by in vitro and in vivo screening techniques. Application of culture filtrate of RC-2 inhibited disease on mulberry leaves, indicating that suppression was due to antifungal compounds in the filtrate. Development of mulberry anthracnose on mulberry leaves was inhibited only when the culture filtrate was applied before fungal inoculation, and it was not inhibited by application after inoculation. These results suggest that the antifungal compounds in the filtrate exhibit a preventive effect on the disease. Peptone significantly increased production of the antifungal compounds. The culture filtrate of RC-2 also inhibited the growth of several other phytopathogenic fungi and bacteria, such as Rosellinia necatrix, Pyricularia oryzae, Agrobacterium tumefaciens, and Xanthomonas campestris pv. campestris, in vitro. From the culture filtrate of RC-2, seven kinds of antifungal compounds were isolated by high performance liquid chromatography analysis, and one of the compounds was determined as iturin A2, a cyclic peptide, by nuclear magnetic resonance and fast atom bombardment mass analysis.

DOI： 10.1094/PHYTO.2001.91.2.181

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The changes of Al species in the presence of montmorillonite (Mt) with aging were investigated using 27Al-nuclear magnetic resonance and inductively coupled plasma atomic emission spectroscopy after extraction with 1 mol L^-1 KCl. Composition of the Al species in a hydroxyaluminosilicate (HAS) solution with a Si/Al molar ratio of 0.63 without Mt was not appreciably affected by 42 d of aging. In the absence of Mt, the concentration of Al13 ([Al0₄Al¹²(OH)₂₄- H₂O)₁₂]₇₊) in the HAS solution with a Si/Al molar ratio of 0.09 and hydroxy-aluminum (HyA) solution decreased during 42 d of aging, suggesting that degradation (or polymerization) of Al13 took place upon aging. In the presence of Mt, Al₁₃ was adsorbed onto Mt from the HyA and HAS(0.09) solutions. The adsorbed Al₁₃ was partly recovered by 1 mol L_-1 KCl from HyA- and HAS(0.09)Mt complexes after 42 d of aging, suggesting that at least a part of the adsorbed Al₁₃ was exchangeable and the rest was considerably stabilized by adsorption onto Mt. The desorption ratios of Al from the HyA- and HAS(O.09)Mt complexes accounted for 25 to 30% and 6 to 8% of total Al adsorbed, respectively. The species of Al desorbed from these complexes consisted mainly of Al₁₃ and Al_NON. The Al_NON was attributed to electrically asymmetric Al including HAS and/or polymer HyA ions.

DOI： 10.1080/00380768.2001.10408397

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A single EAG-active component was found in a pheromone extract from virgin females of the tussock moth, Orgyia postica. This compound named posticlure possesses a trans-epoxy ring and was identified as (6Z,9Z,11S,12S)-11,12-epoxyhenicosa-6,9-diene by means of GC-MS, ¹H NMR and chiral HPLC analyses, and further chemical derivation followed by the GC-MS analysis. In a field test with the pheromone synthesized stereoselectivity, the male moths were specifically attracted to the (11S,12S)-isomer but not to the antipode.

DOI： 10.1016/S0040-4039(00)02038-4

記述言語：英語   掲載種別：研究論文（学術雑誌）  

L-Canavanine is a nonprotein amino acid contained in jack bean [Canavalia ensiformis (L.) DC] and shows a plant inhibitory effect. The inhibitory effect was determined by an immersion test and a microdrop test that employed rice seedlings. L-Canavanine inhibited elongation of the second leaf sheath of rice seedlings more than other natural bioactive substances, such as salicylic acid and cinnamic acid. The modified microdrop test revealed that the mode of action of L-canavanine had no relation to gibberellin synthesis. In the microdrop test, the inhibitory effect of L-canavanine was decreased by simultaneous addition of L-arginine, an analog of L-canavanine. Free amino acid analysis of rice shoots clearly showed that L-canavanine induced an unusual accumulation of L-arginine. However, accumulation of L-arginine did not cause the inhibitory effect on plant growth. These results suggest that the mechanism of inhibition of L-canavanine is closely related to the inhibition of arginine metabolism.

DOI： 10.1023/A:1005659714947

記述言語：日本語  

Allelochemicals

記述言語：英語   掲載種別：研究論文（学術雑誌）  

2-Methoxy-2-(2-naphthyl)propionic acid 1 and 2-hydroxy-2-(2-naphthyl)propionic acid 2 were prepared by the Grignard reaction of 2-naphthylmagnesium bromide with (1R,2S,5R)-(-)-menthyl pyruvate. The absolute configurations of (+)-1 and (+)-2 were determined to be S by the ¹H NMR anisotropy method. Copyright (C) 2000 Elsevier Science Ltd.

DOI： 10.1016/S0957-4166(00)00233-0

記述言語：日本語  

クレオメに含まれる他感作用の強い揮発性物質の同定

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Fundamentals and Applications of Soil Colloid Science(19)

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

カラシナから発生するAITCを利用して雑草防除を行うため，レタスおよび雑草種子の発芽抑制効果を明らかにした。1. 土壌50mLあたり濃度50mg/LのAITC水溶液20mL添加でレタスの発芽が抑制された。2. 土壌50mLあたりカラシナ生葉1g以上の混和量でレタスの発芽が抑制された。このときのAITC濃度は摩砕した生葉1gで24時間後に0.65mg/Lでピークとなった。40℃ではこれよりピークが早く現れ，高濃度が長時間維持された。3. アオビユでは，レタスと同程度の発芽抑制効果が認められたが，イヌビエでは十分な効果が得られなかった。

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The possible role of mucilage in protecting roots from aluminum (Al) injury was investigated in Zea mays L. (cv. Golden Cross Bantam), focusing on binding of Al with mucilage and effects of mucilage on Al toxicity. Al was bound to mucilage after the treatment of roots with 10-50 μM Al for 1 h and 30 μm Al for 30, 60, 90 and 120 min. Using molecular sieve chromatography (Sephadex G-100), Al was co-eluted with a high molecular mass sugar and a low molecular mass sugar. The difficulty in desorbing Al from mucilage with organic acids confirmed the strong binding strength of Al by mucilage revealed by ²⁷Al nuclear magnetic resonance (NMR). Al could not be desorbed completely by succinic, malic, oxalic and citric acid at a molar ratio of 1:1. It could only be completely removed by oxalic acid at a molar ratio of 20:1 (oxalate:Al). Bioassay experiments showed that cell viability and callose formation were unaffected by Al bound to mucilage. However, mucilage deprived roots had only 0.21-0.59 nmol apex^-1 higher Al content than control roots after treatment with 30 μM Al for 1, 1.5 and 2 h. Moreover, inhibition of root elongation by 5 μM Al for 6, 12, 24 and 36 h was independent of the presence or absence of mucilage prior to the Al treatment. These results indicate that although mucilage affects the accumulation of Al by roots, it does not confer Al resistance to Z. mays root apices.

DOI： 10.1034/j.1399-3054.2000.108002152.x

記述言語：日本語  

We conducted experiments for the humic acid adsorption by allophane, ferrihydrite, activated charcoal and micro charcoal to clarify the mechanisms involved in the accumulation of humic substances in Andisols. Adsorption envelopes indicated that: 1) the adsorption patterns of humic acid on these materials from equilibrium pH 4 to 6 showed that the amount of humic acid sorbed was the largest for allophane folowed by activated charcoal, ferrihydrite and micro charcoal; 2) there were many differences between activated charcoal and micro charcoal in regards to their humic acid adsorption properties; and 3) many researches indicated that the amount of active Al was much larger than that of micro charcoal in Andisols. From these results, we concluded that active Al plays an important role in the accumulation of humic substances in Andisols, as indicated by Kobo and Oba, Wada and Higashi, Shoji, and Inoue and Higashi.

DOI： 10.20710/dojo.71.1_1

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Mugineic acid (MA), which is a multidentate phytosiderophore, is exuded to the rhizosphere by the roots of graminaceous plants (e.g. barley) growing under Fe-deficient conditions, resulting in the dissolution of Fe as a form of MA-Fe¹¹¹ complex (MAFe). To clarify the effects of soil chemical properties on the amount of Fe dissolved by MA, an experiment to study the reaction of MA using 38 soil samples was conducted, and the concentrations of free MA (uncomplexed and non-adsorbed MA) and MAFe in solution and the amounts of MA adsorbed on the soils were determined after the reaction. Soil pH value was a good indicator to predict the behavior of MA in soils. A large proportion of added MA was adsorbed on soils or formed MAFe in solution in acidic soils, whereas it did not react with soils and occurred as free MA in alkaline soils. These features were in good agreement with the interaction of MA with Fe (hydr)oxides, as reported in previous papers. Other soil chemical properties, such as soil organic carbon (SOC) content and the amount of amorphous (hydr)oxide components, also affected the behavior of MA in the soils. The Fe dissolution ability of MA was compared with that of diethylenetriaminepentaacetic acid (DTPA) soil test. Although the amounts of extractable Fe were similar between the MA extraction and DTPA soil test, factors influencing the amount of Fe dissolved (formation constant with Fe¹¹¹, reaction pH, rate constant, etc.) were different between both chelating compounds.

DOI： 10.1080/00380768.2000.10409132

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The forms of Al for uptake by the roots and translocation from the root to the shoot were investigated in a buckwheat (Fagopyrum esculentum Moench, cv. Jianxi) that accumulates Al in its leaves. The Al concentration in the xylem sap was 15-fold higher in the plants exposed to AlCl₃ than in those exposed to an Al-oxalate (1:3) complex, suggesting that the roots take up Al in the ionic form. The Al concentration in the xylem sap was 4-fold higher than that in the external solution after a 1-h exposure to AlCl₃ solution and 10-fold higher after a 2-h exposure. The Al concentration in the xylem sap increased with increasing Al concentration in the external solution. The Al uptake was not affected by a respiratory inhibitor, hydroxylamine, but significantly inhibited by the addition of La. These results suggest that Al uptake by the root is a passive process, and La³⁺ competes for the binding sites for Al³⁺ on the plasma membrane. The form of Al in the xylem sap was identified by ²⁷Al-nuclear magnetic resonance analysis. The chemical shift of ²⁷Al in the xylem sap was around 10.9 ppm, which is consistent with that of the Al-citrate complex. Furthermore, the dominant organic acid in the xylem sap was citric acid, indicating that Al was translocated in the form of Al-citrate complex. Because Al is present as Al-oxalate (1:3) in the root, the present data show that ligand exchange from oxalate to citrate occurs before Al is released to xylem.

DOI： 10.1007/s004250000292

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Colletotrichum dematium, the causal agent of mulberry anthracnose, was examined to produce phytotoxins in vitro and in planta. Raw and autoclaved mulberry leaves infected with the fungus, as well as the fungus incubated with several solid or liquid media, were extracted with acetone. Extracts obtained from the fungus grown on raw and autoclaved mulberry leaves caused brown necrotic lesions on susceptible mulberry leaves when they were placed (10 μl) on the wounded adaxial surface. Whereas, no extracts obtained from media, except inoculated medium containing homogenized mulberry leaves, induced the necrosis, suggesting that the fungus produced phytotoxins in planta and that some components in mulberry leaves may be indispensable substrates for producing the toxins. The phytotoxins obtained from the diseased leaves induced necrosis on nonhost plants leaves as well as on mulberry leaves. The toxins were present in the border of anthracnose lesions on the leaves, and the sensitivity to the toxin correlated with that to the fungus infection in each susceptible or resistant mulberry cultivar. These results suggest that the phytotoxins are host nonspecific and play a role in fungal pathogenesis in the development of the lesions. Four toxic compounds were isolated and purified from anthracnose lesions. However, due to the low yield, the chemical structure of the compounds could not be identified.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

土壌中で起こる吸着反応のメカニズムには, イオン交換反応, 配位子交換反応, 疎水的相互作用など, いくっかのタイプが知られている。
本講では, 土壌を構成しているコロイド成分ごとに, 想定される吸着反応メカニズムとその反応特性を解説する。また, これら吸着反応の解析例として,(1) 1pKモデルとStern-Gouy-Chapman (SGC) モデルを組合わせたSite Bindingモデル (1pK-SGCモデル) による表面水酸基の変異荷電発生のモデル,(2) 吸着表面の不均一性と吸着質の非理想的な挙動を配慮に入れたNICA (Non-ldeal Competitive Adsorption) モデルを紹介する。

DOI： 10.11408/jjsidre1965.68.6_597

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Three new triterpenoid-type saponins were isolated from leaves of Duranta repens using plant growth inhibiting activity against seedlings of Brassica juncea var. cernua as a guide for fractionation. The structures of these compounds were elucidated as polygalacic acid-3-O-β-D-glucopyranosido- 28-O-[α-L-rhamnopyranosyl-(1 → 3')-β-D-apiofuranosyl-(l → 4)-α-L- rhamnopyranosyl(1 → 2)-β-L-arabinopyranoside] (durantanin I), polygalacic acid-3-O-β-D-glucopyranosido-28-O-[α-L-rhamnopyranosyl-(1 → 3)-β-D- xylopyranosyl-(1 → 4)-[β-D-apiofuranosyl-(1 → 3)]-α-L-rhamnopyranosyl-(1 → 2)-β-L-arabinopyranoside] (durantanin II), and polygalacic acid-3-O-β-D- glucopyranosido-28-O-[α-L-rhamnopyranosyl-(l → 3)-β-D-xylopyranosyl-(1 → 4)-α-L-rhamnopyranosyl(1 → 2)-β-L-arabinopyranoside] (durantanin III).

DOI： 10.1016/S0031-9422(99)00408-2

記述言語：日本語  

We compared the spectroscopic and physicochemical properties of the humic acids isolated from charred grassland plants after HNO_3 treatment (C-HA) and from the A horizon of Kuro- bokudo (S-HA). 1) The shapes of the absorption curves in the UV and visible regions of the C-HA and S-HA were featureless, and their humic acids belonged to the A-type. 2) The carbon and hydrogen contents of C-HA were almost the same as those of S-HA, while the nitrogen content of C-HA was much higher than that of S-HA and the oxygen content of C-HA was lower than that of S-HA. The atomic [O]/[C] and [O]/[H] ratios of C-HA were lower than those of S-HA. These analytical data of C-HA, except for the nitrogen content, fell within the ranges of those of A-type soil humic acids reported previously. 3) The ^<13>C-NMR spectra of C-HA and S-HA were similar to each other, and the values of their carbon species were in the order of aromatic-C ≫ carbonyl- C > carbohydrate-C≒aliphatic-C. The values of the aromatic-C and carbonyl-C were lower in C-HA than in S-HA. The reverse was true for carbohydrate-C and aliphatic-C. 4) The FT-IR spectrum of C-HA resembled that of S-HA. 5) The XRD patterns of C-HA and S-HA indicated that these humic acids had graphite-like structures.

DOI： 10.20710/dojo.70.6_769

記述言語：日本語  

ヒガンバナの他感作用とその作用物質リコリンおよびクリニンの同定

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Enantiopure 2-hydroxy-2-(1-naphthyl)propionic acid (+)-2 was prepared by the stereoselective Grignard reaction of 1-naphthylmagnesium bromide with (1R,3R,4S)-menthyl pyruvate 3 or (1R,3R,4S)-8-phenylmenthyl pyruvate 4, and the absolute configuration of acid (+)-2 was unambiguously determined to be S by the ¹H NMR anisotropy method.

DOI： 10.1016/S0957-4166(99)00451-6

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Biological activities of plant growth inhibitors from Duranta repens

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Mode of action of a new plant growth inhibitor, Durantanin II.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

When cucumber seeds were sown on agar containing L-3, 4-dihydroxyphenylalanine (L-DOPA), the growth of cucumber seedlings was strongly inhibited by L-DOPA immediately after sowing. However, they recovered from the inhibitory effect of L-DOPA 12 days after sowing. Throughout the experimental period, blacking of agar was observed in the medium containing L-DOPA due to chemical alteration of L-DOPA in agar associated with a polymerization reaction. In the roots of cucumber seedlings treated with L-DOPA, accumulation of L-DOPA and free amino acids was observed compared with the control. Especially, the amount of tyrosine and phenylalanine with a similar chemical structure to that of L-DOPA increased remarkably. It was assumed that the increase was due to the metabolim of L-DOPA to other harmless amino acids. This transformation of L-DOPA could be one of the detoxification mechanisms responsible for the recovery from the inhibitory effects of L-DOPA.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Interaction between Soils and Organic Acids Secreted from Plant Roots-Adsorption Reactions by Soils and Dissolution Reactions by Organic Acids

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To examine the possibility that the A1₁₃ polymer ([A1O₄A1₁₂(OH)₂₄(H₂O)₁₂]⁷⁺) could be formed in soils after gypsum application, an analytical method using a cation exchange resin and ²⁷A1 nuclear magnetic resonance (NMR) spectroscopy was applied to gypsum-treated Kitakami Andosol (fine, mixed, mesic, Andic Dystrochrept). The NMR spectra of the cation exchange resins which retained artificially synthesized hydroxy-Al, showed two broad peaks at 0 and 63 ppm. These results indicated that monomer and/or dimer Al and A1₁₃ polymers adsorbed on the cation exchange resin could be detected with ²⁷A1 NMR. The amount of polymer A1 increased by gypsum application in the Kitakami soil. The NMR spectrum of this resin showed only one peak at 0 ppm indicating that the polymer A1 formed in the gypsum treated Kitakami soil was not the A1₁₃ polymer.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

When cucumber seeds were sown on agar containing L-3, 4-dihydroxyphenylalanine (L-DOPA), the growth of cucumber seedlings was strongly inhibited by L-DOPA immediately after sowing. However, they recovered from the inhibitory effect of L-DOPA 12 days after sowing. Throughout the experimental period, blacking of agar was observed in the medium containing L-DOPA due to chemical alteration of L-DOPA in agar associated with a polymerization reaction. In the roots of cucumber seedlings treated with L-DOPA, accumulation of L-DOPA and free amino acids was observed compared with the control. Especially, the amount of tyrosine and phenylalanine with a similar chemical structure to that of L-DOPA increased remarkably.
It was assumed that the increase was due to the metabolim of L-DOPA to other harmless amino acids. This transformation of L-DOPA could be one of the detoxification mechanisms responsible for the recovery from the inhibitory effects of L-DOPA.

DOI： 10.3719/weed.44.132

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Interaction between Soils and Organic Acids Secreted from Plant Roots. Adsorption Reactions by Soils and Dissolution Reactions by Organic Acids.:Adsorption Reactions by Soils and Dissolution Reactions by Organic Acids

DOI： 10.1271/kagakutoseibutsu1962.37.454

記述言語：日本語  

Five snow samples collected on Mt. Hachimantai (1400 m a. s. l. ) in the months of May and June from 1991 to 1996 contained significant amounts of eolian dust. Fifty-four rainwater samples were collected at Morioka from Jan. 17, 1992 to Apr. 27, 1994 and at Fukaura from Sept. 28, 1992 to Feb. 3, 1995 ; areas located in Northeast Japan. The pH values, concentration of chemical components, and amount of eolian dust in the rainwater samples were determined. Fifteen percent and 27&#37; of the rainwater samples from Morioka and Fukaura, respectively, were acid rain. About 76 and 57&#37; of the inorganic dust deposits in the rainwater samples from Morioka and Fukaura, respectively, were dominated by a <20 μm fraction and their depositions were marked from winter to spring, suggesting a strong influence of Asian long-range eolian dust. The annual deposition of nssSO_4^<2-> and nssCa^<2+> in rainwater was 4.5 and 4.0 meq m^<-2> in Morioka and 6.2 and 7.1 meq m^<-2> in Fukaura, respectively. The chemical compositions of eolian dust deposits in the rainwater samples were compared with Chinese loess and Hachimantai eolian dust in snow deposits. These deposits were characterized by almost the same chemical, physical and mineralogical properties. Sulfate in the Morioka rainwater is transported from China. In addition, the relatively low E factors of SO_4^<2-> of Japanese rainwater samples were partially influenced by sea salt, especially in the winter season. A significant correlation between the amounts of nssSO_4^<2-> and nssCa^<2+> of eolian dust deposits in rainwater samples suggests that nssSO_4^<2-> and most of the nssCa^<2+> and nssK^+ were dissolved from Asian long-range eolian dust contained in the rainwater samples. The annual deposition of nssSO_4^<2-> and nssCa^<2+> in Northeast Japan was 1.5 to 2 times higher for nssSO_4^<2-> and 3 to 5 times higher for nssCa^<2+> than that in Southwest Japan. The present results suggest that the rainwater samples in Northeast Japan are strongly influenced by Asian long-range eolian dust.

記述言語：日本語  

植物生育阻害活性を持った三種類の新規物質の化学構造と生物活性

記述言語：日本語  

寒天を利用した「サンドイッチ法」による植物の葉から出る他感物質の検定

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To differentiate chemical species of Al in soil solutions, a method using nuclear magnetic resonance (NMR) was applied to laboratory preparations of hydroxyaluminum (HyA) and hydroxyaluminosilicate (HAS) ions ([OH]/[Al] = 2.0), and 1 M KCl extracts from acidic soils. The Al in a Al-OH-Si(OH)₄ mixture was separated into three fractions: Al₁₃ ([AlO₄Al₁₂(OH)₂₄(H₂O)₁₂]⁷⁺), Al(SYM), and Al(NON). The Al₁₃ and Al(SYM) were quantitatively determined by ²⁷Al-NMR at 63 and 0 ppm, respectively. The Al(NON) was defined as the Al that cannot be determined by ²⁷Al-NMR. The Al(SYM) was attributed to electrically symmetric octahedral Al including monomer (and dimer) HyA ions, and the Al(NON) was attributed to electrically asymmetric Al including HAS and polymer HyA ions. The concentrations of Al₁₃ decreased with increasing Si/Al molar ratio of the mixed solutions, and Al₁₃ was not detected at Si/Al ≤ 0.28. With increasing Si/Al molar ratio, the concentration of Al(SYM) increased slightly, while Al(NON) increased significantly. In the KCl extracts from soils, the Al₁₃ was not detected at all. This result suggests that Al₁₃ is not formed in these soils, or that the persistence of Al₁₃ in the soil solution is strongly inhibited by adsorption or precipitation reactions. The presence of organically complexed Al (Al(ORG)) was also directly detected in KCl extracts from upper horizons by ²⁷Al-NMR spectra. The chemical shift of resonance peak of Al(ORG) was close to that of the 1:1 complex of Al oxalate. On average, 92 and 96% of the KCl-exchangeable Al existed as Al(SYM) and Al(SYM) plus Al(ORG), respectively.

DOI： 10.2136/sssaj1998.03615995006200030012x

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Hydroxyaluminosilicate (HAS) ions were prepared from solutions containing hydroxyaluminum (HyA) ions and orthosilicic acids at an Al concentration of ≈4 mM; Si/Al molar ratios of 0, 0.25, 0.5, and 1.0; and NaOH/Al molar ratios of 1.0, 2.0, and 2.5. Phosphate retention behavior of montmorillonite (Mt) carrying nonexchangeably adsorbed HyA, HAS ions, or both (HyA/HAS-Mt complexes) was studied at equilibrating solution pH of ≈5.0. The HyA/HAS-Mt complexes showed larger phosphate retention capacities than untreated Mt. Retention of phosphate by these complexes at 0.5 to 50 mM initial P concentrations decreased with increasing NaOH/Al and Si/Al ratios of the hydroxy materials adsorbed on Mt. Phosphate, probably retained initially through surface complexation and ligand exchange reactions principally with OH or OH₂ groups, coordinated with Al atoms at the broken edges of HyA or HAS polymers adsorbed on the external planar surfaces and in the interlayer spaces of Mt. This was followed by expulsion of the phosphated hydroxy materials from the Mt interlayers to the ambient solution, and finally, precipitation as amorphous Al-phosphate solid phases. Results of this study thus merit attention in P-fertility management as well as indicate a probable P-induced weathering process in acidic nonallophanic Andisols and in Red-Yellow soils (Hapludalfs and Hapludults) with a predominance of hydroxy-interlayered minerals.

DOI： 10.2136/sssaj1998.03615995006200040011x

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Interactions of 100 μmol L^-1 mugineic acid (MA) with synthetically produced Fe (hydr)oxides (goethite, hematite, lepidocrocite, and ferrihydrite) as influenced by 100 mmol L^-1 SO₄ ^2- and phosphate were studied at equilibrium in the pH range from 3 to 11. In the presence of SO₄ ^2-, the concentrations of total MA [i.e., free MA+Fe(III)-MA complexes] and Fe(III) dissolved by MA in the filtrates were higher than those in the presence of 100 mmol L^-1 Cl^- at pH<7. Sulfate increased the formation of Fe(III)-MA complexes indirectly by reducing the adsorption of MA and Fe(III)-MA by the Fe (hydr)oxides. The adsorption of MA by the Fe (hydr)oxides and consequently the MA-promoted dissolution of Fe(III) from ferrihydrite and lepidocrocite were greatly inhibited by the adsorption of phosphate. The slight dissolution of Fe(III) between pH 5 and 9 is partly attributed to the formation of soluble Fe(III)-phosphate complexes. Although MA does not react directly with Fe (hydr)oxides in the presence of excess phosphate, MA would promote the dissolution reaction of Fe(III) by phosphate. The sequence of adsorption affinity for the Fe (hydr)oxides was found to be: phosphate≫MA>Fe(III)-MA, SO₄ ^2->Cl^-. Our results suggest that SO₄ ^2- and especially phosphate applied as fertilizers may inhibit the MA-promoted dissolution of Fe(III) from Fe (hydr)oxides in soils mainly by displacement of MA from the surface of Fe (hydr)oxides.

DOI： 10.2136/sssaj1998.03615995006200010021x

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Buckwheat (Fagopyrum esculentum Moench. cv Jianxi), which shows high Al resistance, accumulates Al in the leaves. The internal detoxification mechanism was studied by purifying and identifying Al complexes in the leaves and roots. About 90% of Al accumulated in the leaves was found in the cell sap, in which the dominant organic acid was oxalic acid. Purification of the Al complex in the cell sap of leaves by molecular-sieve chromatography resulted in a complex with a ratio of Al to oxalic acid of 1:3. A ¹³C-nuclear magnetic resonance study of the purified cell sap revealed only one signal at a chemical shift 164.4 ppm, which was assigned to the Al-chelated carboxylic group of oxalic acid. A ²⁷Al-nuclear magnetic resonance analysis revealed one major signal at the chemical shift of 16.0 to 17.0 ppm, with a minor signal at the chemical shift of 11.0 to 12 ppm in both the intact roots and their cell sap, which is consistent with the Al-oxalate complexes at 1:3 and 1:2 ratios, respectively. The purified cell sap was not phytotoxic to root elongation in corn (Zea mays). All of these results indicate that Al tolerance in the roots and leaves of buckwheat is achieved by the formation of a nonphytotoxic Al-oxalate (1:3) complex.

DOI： 10.1104/pp.117.3.753

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Mugineic acid (MA; (2S, 2′S, 3′S, 3″S)-N-[3-carboxy-3-(3-carboxy-3-hydroxypropylamino)-2-hydroxypropyl]-azetidine-2-carboxylic acid), a multidentate complexing agent, is exuded by the roots of graminaceous plants (e.g. barley) growing under Fe-deficient conditions. The nature of the interactions of MA with Fe (hydr)oxide minerals in soils is thus of considerable practical importance. To examine the availability of MA in dissolving Fe (hydr) oxides, we investigated the amounts of Fe dissolved from 24 samples of Fe (hydr)oxides by 100 μM MA (Fe_MA) and 200 mM NH4-oxalate (Fe_o). The Fe_o values were much larger than the Fe_MA ones, though the crystallinity of the Fe (hydr)oxides was a significant factor. For Fe (hydr)oxides consisting of goethite, hematite, ferrihydrite, and their mixture, Fe_MA increased with the increase of Fe_o, indicating that FeMA would be correlated with FeD, that is the amount of short-range ordered Fe minerals including ferrihydrite. For goethite, hematite, magnetite, maghemite, and lepidocrocite with a high crystallinity, MA was relatively ineffective in dissolving Fe, although a part of crystalline magnetite, maghemite, and lepidocrocite could be dissolved by NH₄-oxalate. For soils containing significant amounts of magnetite, maghemite, lepidocrocite, it is unlikely therefore that Fe_o would be a useful indicator of plant-available Fe.

DOI： 10.1080/00380768.1998.10414453

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

An internal detoxification mechanism for Al was investigated in an Al-accumulating plant, hydrangea (Hydrangea macrophylla), focusing on Al forms present in the cells. The leaves of hydrangea contained as much as 15.7 mmol Al kg(-1) fresh weight, and more than two-thirds of the Al was found in the cell sap. Using Al-27-nuclear magnetic resonance, the dominant peak of Al was observed at a chemical shift of 11 to 12 parts per million in both intact leaves and the extracted cell sap, which is in good accordance with the chemical shift for the 1:1 Al-citrate complex. Purification of cell sap by molecular sieve chromatography (Sephadex G-10) combined with ion-exclusion chromatography indicated that Al in fractions with the same retention time as citric acid contributed to the observed Al-27 peak in the intact leaves. The molar ratio of Al to citric acid in the crude and purified cell sap approximated 1. The structure of the ligand chelated with Al was identified to be citric acid. Bioassay experiments showed that the purified Al complex from the cell sap did not inhibit root elongation of corn (Zea mays L.) and the viability of cells on the root tip surface was also not affected. These observations indicate that Al is bound to citric acid in the cells of hydrangea leaves.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

It had been suggested that cyanidin 3-O-(6″-O-monomalonyl-β-glucopyranoside) and another unknown compound occur as major pigments in the purplish-red flower of chrysanthemum (Dendranthema grandiflorum). We determined the structure of the unknown compound as cyanidin 3-O-(3″,6″-O-dimalonyl-β-glucopyranoside) by FAB-MS and ¹H-NMR. This is the first report of the identification of the cyanidin 3-dimalonyl glucoside as a flower pigment.

DOI： 10.1271/bbb.61.1607

記述言語：日本語  

ナガボノウルシ(Sphenoclea zeylanica)に含まれる植物生長阻害物質

記述言語：英語   掲載種別：研究論文（学術雑誌）  

An internal detoxification mechanism for Al was investigated in an Al-accumulating plant, hydrangea (Hydrangea macrophylla), focusing on Al forms present in the cells. The leaves of hydrangea contained as much as 15.7 mmol Al kg^-1 fresh weight, and more than two-thirds of the Al was found in the cell sap. Using ²⁷Al-nuclear magnetic resonance, the dominant peak of Al was observed at a chemical shift of 11 to 12 parts per million in both intact leaves and the extracted cell sap, which is in good accordance with the chemical shift for the 1:1 Al-citrate complex. Purification of cell sap by molecular sieve chromatography (Sephadex G-10) combined with ion-exclusion chromatography indicated that Al in fractions with the same retention time as citric acid contributed to the observed ²⁷Al peak in the intact leaves. The molar ratio of Al to citric acid in the crude and purified cell sap approximated 1. The structure of the ligand chelated with Al was identified to be citric acid. Bioassay experiments showed that the purified Al complex from the cell sap did not inhibit root elongation of corn (Zea mays L) and the viability of cells on the root tip surface was also not affected. These observations indicate that Al is bound to citric acid in the cells of hydrangea leaves.

DOI： 10.1104/pp.113.4.1033

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語  

ナガボノウルシ(Sphennoclea zeylanica)に含まれる新規植物生長阻害物質

開催年月日： 2024年12月

記述言語：英語   会議種別：ポスター発表  

開催地：Zhengzhou   国名：中華人民共和国  

開催年月日： 2024年12月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：鹿児島市   国名：日本国  

開催年月日： 2024年12月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：鹿児島市   国名：日本国  

開催年月日： 2024年12月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：宇都宮市   国名：日本国  

開催年月日： 2024年10月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：つくば市   国名：日本国  

開催年月日： 2024年10月

記述言語：英語   会議種別：ポスター発表  

開催地：つくば市   国名：日本国  

開催年月日： 2024年9月

記述言語：英語   会議種別：ポスター発表  

開催地：福岡   国名：日本国  

開催年月日： 2024年9月

記述言語：日本語   会議種別：ポスター発表  

開催地：福岡   国名：日本国  

開催年月日： 2024年9月

記述言語：日本語   会議種別：ポスター発表  

開催地：福岡   国名：日本国  

開催年月日： 2024年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：福岡   国名：日本国  

開催年月日： 2024年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：福岡   国名：日本国  

開催年月日： 2024年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：福岡   国名：日本国  

開催年月日： 2024年9月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：福岡   国名：日本国  

開催年月日： 2024年6月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：帯広   国名：日本国  

開催年月日： 2024年6月

記述言語：英語   会議種別：ポスター発表  

開催地：帯広   国名：日本国  

開催年月日： 2024年5月

記述言語：英語   会議種別：ポスター発表  

国名：モロッコ王国  

開催年月日： 2024年3月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2023年12月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2023年12月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2023年12月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2023年12月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2023年12月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2023年12月

記述言語：英語   会議種別：口頭発表（一般）  

国名：アメリカ合衆国  

開催年月日： 2023年12月

記述言語：英語   会議種別：口頭発表（一般）  

国名：アメリカ合衆国  

開催年月日： 2023年10月

記述言語：英語   会議種別：口頭発表（一般）  

国名：台湾  

開催年月日： 2023年9月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2023年9月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

Input of nitrogen suppresses soil respiration but promotes dissolved organic carbon release in a non-allophanic Andosol

開催年月日： 2023年9月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2023年9月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2023年9月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2023年9月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2023年9月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2023年9月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2023年4月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2023年3月

記述言語：日本語  

国名：その他  

Water extractable organic matter from air-dry soil to predict soil carbon dynamics

開催年月日： 2023年3月

記述言語：日本語  

国名：その他  

Challenge for building a carbon sequestration model for Japanese Andosols.

開催年月日： 2023年3月

記述言語：日本語  

国名：その他  

Soil carbon dynamics revealed by radiocarbon

開催年月日： 2023年3月

記述言語：日本語  

国名：その他  

開催年月日： 2023年3月

記述言語：日本語  

国名：その他  

開催年月日： 2022年12月

記述言語：日本語  

国名：その他  

開催年月日： 2022年10月

記述言語：日本語  

国名：その他  

開催年月日： 2022年10月

記述言語：日本語  

国名：その他  

開催年月日： 2022年9月

記述言語：日本語  

国名：その他  

開催年月日： 2022年9月

記述言語：日本語  

国名：その他  

開催年月日： 2022年9月

記述言語：日本語  

国名：その他  

開催年月日： 2022年9月

記述言語：日本語  

国名：その他  

開催年月日： 2022年9月

記述言語：日本語  

国名：その他  

開催年月日： 2022年9月

記述言語：日本語  

国名：その他  

開催年月日： 2022年6月

記述言語：英語  

国名：その他  

開催年月日： 2022年3月

記述言語：日本語  

国名：その他  

開催年月日： 2021年12月

記述言語：日本語  

国名：その他  

開催年月日： 2021年12月

記述言語：日本語  

国名：その他  

開催年月日： 2021年9月

記述言語：日本語  

国名：日本国  

開催年月日： 2021年9月

記述言語：日本語  

国名：日本国  

開催年月日： 2021年9月

記述言語：日本語  

国名：日本国  

開催年月日： 2021年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：ZOOMウェビナー   国名：日本国  

開催年月日： 2021年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：新潟オンライン大会   国名：日本国  

開催年月日： 2021年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2020年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンラインWEB会議（第180回秋季講演大会）   国名：日本国  

開催年月日： 2020年3月

記述言語：日本語   会議種別：シンポジウム・ワークショップ パネル（公募）  

開催地：オンライン   国名：日本国  

開催年月日： 2020年3月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2020年3月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2019年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：九州沖縄農業研究センター本所   国名：日本国  

開催年月日： 2019年11月

記述言語：日本語   会議種別：シンポジウム・ワークショップ パネル（公募）  

開催地：山口大学   国名：日本国  

開催年月日： 2019年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：山口大学   国名：日本国  

開催年月日： 2019年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：九州沖縄農業研究センター本所   国名：日本国  

開催年月日： 2019年9月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：静岡大学農学部   国名：日本国  

火山灰土壌中の土壌有機物はほとんど下方へは移動しないことを明らかにした。このことから、火山灰土壌の厚い黒色腐植層は、累積的に積層することによって生成したことが明らかになった。

開催年月日： 2019年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：静岡大学農学部   国名：日本国  

開催年月日： 2019年5月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：幕張メッセ   国名：日本国  

開催年月日： 2019年3月

記述言語：日本語   会議種別：シンポジウム・ワークショップ パネル（公募）  

国名：日本国  

開催年月日： 2019年3月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：神戸市   国名：日本国  

開催年月日： 2019年3月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：神戸市   国名：日本国  

九州地方で蔓延が問題となっている外来雑草セイバンモロコシは，土壌特性によって蔓延する場所が限定されていることを明らかにした．

開催年月日： 2019年3月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：神戸市   国名：日本国  

開催年月日： 2018年10月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Taichung   国名：台湾  

開催年月日： 2018年9月 - 2019年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：日本大学   国名：日本国  

開催年月日： 2018年9月 - 2018年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：日本大学   国名：日本国  

開催年月日： 2015年9月

記述言語：日本語  

国名：日本国  

開催年月日： 2014年9月

記述言語：日本語  

国名：日本国  

開催年月日： 2008年3月

記述言語：日本語  

国名：日本国  

Influence of light quality on allelopathic effects of asparagus through aseptic bioassay

開催年月日： 2007年10月

記述言語：日本語  

国名：日本国  

Cyanamide (NH_2CN) has been isolated from hairy vetch Vicia villosa subsp. varia as a natural product for the first time. We have already clarified that the cyanamide content in hairy vetch seedlings cultivated in the growth chamber reaches its maximum at 3-4 week. The present study aims at elucidating the organ in which cyanamide is biosynthesized. The cyanamide contents in the leaves, the stems, and the roots of 4-week-old seedlings were 629 ± 209, 256 ± 134, and < 20 μg/gFW (average ± SD), respectively. This suggests that cyanamide is biosynthesized in the aerial parts (the leaves plus the stems). To investigate the cyanamide-biosynthesizing organ, we compared the ^^<15>N incorporation into cyanamide in the whole aerial parts to that in the apical portion including the younger leaves. The ^^<15>N isotope abundance ratio in the isolated cyanamide was 3.99 ± 0.61% (average ± SE) when the whole aerial parts was incubated with ^^<15>N-labeled nitrogen sources, which was significantly higher than that of control (0.28 ± 0.03%). In contrast, the cyanamide isolated from the apical portion was not ^^<15>N-labeled on the same condition. These results imply that cyanamide is biosynthesized in the mature leaves.

開催年月日： 2007年9月

記述言語：日本語  

国名：日本国  

Aseptic bioassay for estimation of asparagus allelopathic effects toward asparagus seeds

開催年月日： 2007年8月

記述言語：日本語  

国名：日本国  

開催年月日： 2007年3月

記述言語：日本語  

国名：日本国  

Varietal differences in allelopathic effects of asparagus seedlings

開催年月日： 2006年12月

記述言語：英語  

国名：日本国  

Allelopathic effect of transformed and non-transformed Atropa belladonna as a model of medicinal plants

開催年月日： 2006年9月

記述言語：日本語  

国名：日本国  

開催年月日： 2005年5月

記述言語：日本語  

国名：日本国  

Cyanamide (NH_2CN) has been industrially produced in large quantities for a long time. We have isolated cyanamide as a plant growth inhibitor from hairy vetch Vicia villosa. Although we excluded the possibility that the cyanamide isolated was an unexpectedly contaminating agrochemical, the details of its biosynthesis remain unknown because this compound has never been considered as a natural product. In this report we demonstrate the de novo production of cyanamide in this legume using a ^<15>N-labeled nitrogen source. The extracts of the seedlings of V. villosa grown with and without (^<15>N)nitrate were purified chromatographically to give cyanamide, respectively. On the basis of the GC/MS analyses, the isotopic ratio ^<15>N/(^<14>N+^<15>N) of the ^<15>N-enriched cyanamide was calculated to be 0.143, while that of the non-enriched cyanamide was 0.0065. We also measured the mass spectrum of dicyandiamide [NH_2C(=NH)NHCN], a dimmer of cyanamide, prepared from the purified cyanamide. The isotopic ratio was 0.138, corresponding well to the result of the GC/MS analysis of cyanamide. From these observations, the incorporation of the nitrogen atom of nitrate into cyanamide has been established. We conclude that cyanamide is de novo biosynthesized in V. villosa.

開催年月日： 2003年8月

記述言語：日本語  

国名：日本国  

開催年月日： 2001年12月

記述言語：日本語  

国名：日本国  

Soil Components in Molecular Level and Nano-Scale Interactions among the Components

開催年月日： 2001年3月

記述言語：日本語  

国名：日本国  

開催年月日： 2001年3月

記述言語：日本語  

国名：日本国  

開催年月日： 1997年3月

記述言語：英語  

国名：日本国  

IDENTIFICATION OF AL FORM IN LEAVES OF Hydrangea macrophylla

開催年月日： 1997年3月

記述言語：日本語  

国名：日本国  

Mineralogical and chemical specificity of Andisols in adsorption of pesticide onto soils - The comparison of Andisols and non-Andisols using 2, 4-dichlorophenoxyacetic acid -

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：東北大学   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：名城大学   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：名城大学   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：名城大学   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：佐賀大学   国名：日本国  

記述言語：英語   会議種別：口頭発表（一般）  

開催地：龍谷大学   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

国名：その他  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：東北大学   国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：東北大学   国名：日本国