| 市橋 隆自（いちはし りゆうじ） | データ更新日：2023.11.27 |
准教授 ／
農学研究院
環境農学部門
森林環境科学
| 1. | 山内 耕司朗, 片山 歩美, 市橋 隆自, 久米 朋宣, 井上 幸子, 扇 大輔, 南木 大祐, 中村 琢磨, 九州大学農学部附属演習林宮崎演習林におけるブナ科樹木萎凋病の被害報告, 九州大学農学部演習林報告, 103, 41-44, 2022.03. |
| 2. | 中村 琢磨，長 慶一郎，山内 康平, 緒方 健人, 鍜治 清弘, 佐々木 寛和, 扇 大輔, 井上 幸子, 村田 秀介, 山内 耕司朗, 菱 拓雄, 田代 直明, 市橋 隆自, 鳥獣防除柵の構造的な違いが植栽木への食害や成長および林床植生に与える影響, 九州大学農学部演習林報告, doi.org/10.15017/4776864, 103, 29-39, 2022.03. |
| 3. | Seonghun Jeong, Kyoichi Otsuki, Yoshinori Shinohara, Akio Inoue, Ryuji Ichihashi, Stemflow estimation models for Japanese cedar and cypress plantations using common forest inventory data, Agricultural and Forest Meteorology, 10.1016/j.agrformet.2020.107997, 290, 2020.08, [URL], Although stemflow (SF) had been regarded as a small portion of the gross rainfall (GR), recent studies have revealed that, depending on the forest stand structure, the SF/GR ratio should not be neglected. This study derived SF/GR estimation models using common forest inventory data. A set of SF/GR ratio and forest inventory data (stand density (SD), total basal area (BA), mean diameter at breast height (DBH¯), mean tree height (H¯), canopy cover (CC), and leaf area index (LAI)) was collected from previous studies of Japanese cedar and cypress plantations. To further investigate the relation between SF/GR ratio and forest stand structures, we examined additional stand-structure variables (mean basal area (BA¯), mean stem surface area (SA¯), and total stem surface area (SA)) derived from the inventory data, and the stand-scale funneling ratio (FRstand) evaluating the efficiency of funneling rainwater. Among all the stand-structure variables, SD exclusively determined the SF/GR ratio, providing the best-fitting positive single linear regression equation as a density-based SF/GR model with a root mean square error (RMSE) of 2.4%. Although this model is useful for practical forest water management because it requires only SD which is the most basic forest inventory data, it has a weak point in meticulous forest water management because it cannot reflect the effect of tree growth on SF/GR ratio. Thus, we developed a size-based SF/GR model (RMSE = 2.0%) based on the strong relationship between the FRstand and DBH¯. This model is applicable to meticulous forest water management because it reflects the effects of not only SD but also tree growth by DBH on SF/GR ratio. These models derived from the common forest inventory data are potentially applicable to the evaluation and control of SF in forest water management.. |
| 4. | Ryuji Ichihashi, Hikaru Komatsu, Tomonori Kume, Yoshinori Shinohara, Kenji Tsuruta, Kyoichi Otsuki, Effects of thinning on canopy transpiration of a dense Moso bamboo stand in western Japan, Journal of Forest Research, 10.1080/13416979.2019.1647592, 24, 285-291, 2019.09, [URL]. |
| 5. | Ayumi Katayama, Tomonori Kume, Ryuji Ichihashi, Michiko Nakagawa, Vertical variation in wood CO2 efflux is not uniformly related to height measurement across various species and sizes of Bornean tropical rainforest trees, Tree physiology, 10.1093/treephys/tpz022, 39, 6, 1000-1008, 2019.06, [URL], Limited knowledge about vertical variation in wood CO2 efflux (Rwood) is still a cause of uncertainty in Rwood estimates at individual and ecosystem scales. Although previous studies found higher Rwood in the canopy, they examined several tree species of similar size. In contrast, in the present study, we measured vertical variation in Rwood for 18 trees including 13 species, using a canopy crane for a more precise determination of the vertical variation in Rwood, for various species and sizes of trees in order to examine the factors affecting vertical variation in Rwood and thus, to better understand the effect of taking into account the vertical and inter-individual variation on estimates of Rwood at the individual scale. We did not find any clear pattern of vertical variation; Rwood increased significantly with measurement height for only one tree, while it decreased for two more trees, and was not significantly related with measurement height in 15 other trees. Canopy to breast height Rwood ratio was not related to diameter at breast height or crown ratio, which supposedly are factors affecting vertical variation in Rwood. On average, Rwood estimates at individual scale, considering inter-individual variation but ignoring vertical variation, were only 6% higher than estimates considering both forms of variation. However, estimates considering vertical variation, while ignoring inter-individual variation, were 13% higher than estimates considering both forms of variation. These results suggest that individual measurements at breast height are more important for estimating Rwood at the individual scale, and that any error in Rwood estimation at this scale, due to the absence of any more measurements along tree height, is really quite negligible. This study measured various species and sizes of trees, which may be attributed to no clear vertical variation because factors causing vertical variation can differ among species and sizes.. |
| 6. | Ryuji Ichihashi, Growth characteristics of forest lianas Costs and risks associated with the host-dependent support strategy, Japanese Journal of Ecology, 10.18960/seitai.69.2_71, 69, 2, 71-81, 2019.01, [URL], Although lianas (woody climbers) are a phylogenetically and functionally important group of land plants, there is very little information on individual-scale liana growth in the field. Based on previous studies of temperate liana species, this study investigated how liana plants grow to the forest canopy. The paper discusses the potential benefits and costs associated with the hostdependent support strategy. The host-dependent support habit enables plants to reduce resource investments in mechanical tissues, thereby attaining greater stem extension every year, while maintaining a large leaf-to-stem mass ratio. These features could be a great advantage in competition for light or growth in shady environments. However, this habit requires a continuous search for host structures, and plants can be damaged and even fall to the ground when the hosts collapse. These factors, representing the costs and risks associated with host-dependent growth, may limit plant growth over protracted periods.. |
| 7. | Ryuji Ichihashi, Chen Wei Chiu, Hikaru Komatsu, Tomonori Kume, Yoshinori Shinohara, Makiko Tateishi, Kenji Tsuruta, Kyoichi Otsuki, Contribution of lianas to community-level canopy transpiration in a warm-temperate forest, Functional Ecology, 10.1111/1365-2435.12881, 31, 9, 1690-1699, 2017.09, [URL], Lianas (woody climbers) have a greater amount of leaves relative to basal area or standing biomass than trees, and very wide vessels that permit efficient water transport. These features suggest that lianas possibly consume proportionally more water through transpiration than trees. Despite their potential importance, researchers have made only limited attempts to evaluate effects of lianas on forest water dynamics. We conducted sap flow measurements for 1 year using a thermal dissipation method for four species each of lianas and trees in a liana-rich, warm-temperate forest in Japan and estimated the contribution of lianas to stand canopy transpiration. Based on a calibration measuring water uptake rates from cut-stem ends, the actual sap flux (Fd) in liana stems was several times greater than those estimated from the original calibration provided for the method. In the field, lianas showed an average of 2–4 times greater Fd than trees throughout the year. Except for this difference, diurnal and seasonal patterns of relative changes of Fd were similar in both groups. The whole-plant transpiration (Qt) of sample plants was exponentially related to basal diameter for both lianas and trees; Qt of lianas increased more steeply with basal diameter than that of trees. By extrapolating the relationships between Qt and basal diameter to the inventory data of the study plot, we estimated that lianas contributed 12·8% to the annual stand canopy transpiration while comprising 2·3% of stand basal area, which probably reflected the top-heavy architecture of lianas. Our results indicate that the contribution of lianas to forest water dynamics may be several times greater than their contribution to forest basal area. This implies that a slight increase of liana abundance might have greater effects on water dynamics and, through competitions with trees for limited water, the carbon sequestration capacity of forests than expected from the increase in basal area. This study underlines the necessity of evaluating the relative importance of lianas to forest water dynamics in forests world-wide. A lay summary is available for this article.. |
| 8. | Akihito Ono, Ryosuke Izumi, Hiroki Ishizuka, Kyohei Terao, Hidekuni Takao, Ryuji Ichihashi, Tsuyoshi Kobayashi, Ikuo Kataoka, Fusao Shimokawa, Highly pure phloem-sap-extraction sensor device for direct component analysis of nutrition in plant shoots, 19th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS 2017 TRANSDUCERS 2017 - 19th International Conference on Solid-State Sensors, Actuators and Microsystems, 10.1109/TRANSDUCERS.2017.7994369, 1604-1607, 2017.07, [URL], This paper describes a highly pure phloem-sap-extraction sensor device that mounts a phloem position-identification sensor. Convenient methods of artificially extracting highly pure phloem sap for quantitative analysis of plant nutrition have yet to be established. To realize direct analysis of nutrition as well as long-term monitoring of its component fluctuation, we propose a novel sensor device that can distinguish phloem and xylem positions stably for a long time and extract only pure phloem sap.. |
| 9. | Akihito Ono, Akihito Yoneda, Yuichi Tao, Kyohei Terao, Hidekuni Takao, Ryuji Ichihashi, Tsuyoshi Kobayashi, Ikuo Kataoka, Fusao Shimokawa, Microscale phloem sap extraction sensor device for measuring biological information in plant branches, 15th IEEE Sensors Conference, SENSORS 2016 IEEE Sensors, SENSORS 2016 - Proceedings, 10.1109/ICSENS.2016.7808532, 2017.01, [URL], In this study, a microscale phloem sap extraction sensor device based on MEMS technology is proposed to artificially extract phloem sap and monitor biological information in plant branches. The device consists of electrical resistance sensors to distinguish the positions of vascular bundles (xylem/phloem) and hollow-structured cantilevers with reservoirs for fluid extraction. A prototype of the proposed sensor device was fabricated. Furthermore, the performance of the position-distinction sensor was evaluated, and the feasibility of the fluid-extraction structure was validated.. |
| 10. | Ryuji Ichihashi, Tsuyoshi Kobayashi, Growth and photosynthesis characteristics of invading larch saplings in an occasionally flooded dry stream bed in cool-temperate Japan, Journal of Forest Research, 10.1080/13416979.2017.1350393, 22, 5, 314-319, 2017.07, [URL]. |
| 11. | Kenji Tsuruta, Motonori Okumura, Tomonori Kume, Ryuji Ichihashi, Yoshinori Shinohara, Yoshiko Kosugi, Insignificant effects of culm age on transpiration in a managed Moso bamboo forest, Kyoto, Japan, Hydrological Research Letters, 10.3178/hrl.10.1, 10, 1, 1-7, 2016.01, [URL], The expansion of Moso bamboo forests in Japan might change transpiration and therefore reduce the availability of water resources. Moso bamboo stands are often composed of culms with various ages and older culms may have lower sap flux density (Fd), which may in turn affect individual culm transpiration (Qt), probably because vascular bundles do not regenerate after sprouting. Information related to the differences of Fd and Qt between younger and older culms would be important for (i) understanding the effects of culm age structure changes on stand-scale transpiration (EC), and (ii) developing sampling strategies for EC estimates in Moso bamboo forests. We conducted sap flux measurements for 15 individuals from four culm age classes in a managed Moso bamboo forest in Kameoka, Kyoto, Japan. Differences in Fd were not significant among the four culm age classes with almost the same stem diameter at breast height (DBH). Qt was related to DBH across four age classes, indicating that culm age had no apparent effect on Qt in the forest. Our results suggest the effects of culm age structure changes on EC are small, and contribute to development of sampling strategy without considering culm age structure for EC estimates at this site.. |
| 12. | Ryuji Ichihashi, Masaki Tateno, Biomass allocation and long-term growth patterns of temperate lianas in comparison with trees, New Phytologist, 10.1111/nph.13391, 207, 3, 604-612, 2015.08, [URL], The host-dependent support habit of lianas is generally interpreted as a strategy designed to reduce resource investment in mechanical tissues; this allows preferential allocation to leaf and stem extension, thereby enhancing productivity and competitive abilities. However, this hypothesis has not been rigorously tested. We examined the aboveground allometries regarding biomass allocation (leaf mass and current-year stem mass (approximated as biomass allocated to extension growth) vs total aboveground mass) and long-term apparent growth patterns (height and aboveground mass vs age, i.e. numbers of growth rings) for nine deciduous liana species in Japan. Lianas had, on average, three- and five-fold greater leaf and current-year stem mass, respectively, than trees for a given aboveground mass, whereas the time course to reach the forest canopy was comparable and biomass accumulation during that period was only one-tenth that of co-occurring canopy trees. The balance between the lengths of yearly stem extension and existing older stems indicated that lianas lost c. 75% of stem length during growth to the canopy, which is probably a consequence of the host-dependent growth. Our observations suggest that, although lianas rely on hosts mechanically, allowing for short-term vigorous growth, this habit requires a large cost and could limit plant growth over protracted periods.. |
| 13. | Ryuji Ichihashi, Hikaru Komatsu, Tomonori Kume, Yuka Onozawa, Yoshinori Shinohara, Kenji Tsuruta, Kyoichi Otsuki, Stand-scale transpiration of two moso bamboo stands with different culm densities, Ecohydrology, 10.1002/eco.1515, 8, 3, 450-459, 2015.04, [URL], The large-scale expansion of Moso bamboo forests in Japan raises concerns about how vegetation will affect the hydrological cycle and local water resources. However, information on transpiration (E) is limited to study on a single bamboo stand with low culm density (4000ha-1). The present study conducted a year-round measurement of E in a high-density (11000ha-1) stand using sap-flow measurements, and additional measurements were made during summer in the previously studied low-density stand and a neighbouring Japanese cedar stand for comparison. Annual E of the high-density stand was estimated at 455mm. Although the value was greater than those reported for neighbouring coniferous forests (250-370mm), it was lower than previous measurements made in the low-density stand (567mm). The daytime sap flux density of the high-density stand was generally less than half that in the low-density stand, resulting in similar daily maximum E values in those stands. In addition, E typically peaked before midday in the high-density stand followed by a rapid decline; the midday suppression of E led to decreased total E in the stand. Based on present and previous measurements of E, combined with the lower rainfall interception (I) reported for bamboo stands, water loss through evapotranspiration would be comparable between bamboo and coniferous forests. Present results also suggest that the E of bamboo stands does not have strong positive relationships with stand structural parameters (e.g., culm density and sapwood area) but possibly depends more on the sites' microenvironments (e.g., solar radiation).. |
| 14. | Hironori Toyama, Tsuyoshi Kajisa, Shuichiro Tagane, Keiko Mase, Phourin Chhang, Vanna Samreth, Vuthy Ma, Heng Sokh, Ryuji Ichihashi, Yusuke Onoda, Nobuya Mizoue, Tetsukazu Yahara, Effects of logging and recruitment on community phylogenetic structure in 32 permanent forest plots of kampong thom, cambodia, Philosophical Transactions of the Royal Society B: Biological Sciences, 10.1098/rstb.2014.0008, 370, 1662, 1-13, 2015.02, [URL], Ecological communities including tropical rainforest are rapidly changing under various disturbances caused by increasing human activities. Recently in Cambodia, illegal logging and clear-felling for agriculture have been increasing. Here, we study the effects of logging, mortality and recruitment of plot trees on phylogenetic community structure in 32 plots in Kampong Thom, Cambodia. Each plot was 0.25 ha; 28 plots were established in primary evergreen forests and four were established in secondary dry deciduous forests. Measurements were made in 1998, 2000, 2004 and 2010, and logging, recruitment and mortality of each tree were recorded. We estimated phylogeny using rbcL and matK gene sequences and quantified phylogenetic a and b diversity. Within communities, logging decreased phylogenetic diversity, and increased overall phylogenetic clustering and terminal phylogenetic evenness. Between communities, logging increased phylogenetic similarity between evergreen and deciduous plots. On the other hand, recruitment had opposite effects both within and between communities. The observed patterns can be explained by environmental homogenization under logging. Logging is biased to particular species and larger diameter at breast height, and forest patrol has been effective in decreasing logging.. |
| 15. | Hikaru Komatsu, Yoshinori Shinohara, Tomo'omi Kumagai, Tomonori Kume, Kenji Tsuruta, Yang Xiang, Ryuji Ichihashi, Makiko Tateishi, Takanori Shimizu, Yoshiyuki Miyazawa, Mari Nogata, Sophie Laplace, Tseng Han, Chen Wei Chiu, Akira Ogura, Takami Saito, Kyoichi Otsuki, A model relating transpiration for Japanese cedar and cypress plantations with stand structure, Forest Ecology and Management, 10.1016/j.foreco.2014.08.041, 334, 301-312, 2014.12, [URL], Previous studies have revealed that changes in forest structure due to management (e.g., thinning, aging, and clearcutting) could affect the forest water balance. However, there are unexplained variability in changes in the annual water balance with changing structure among different sites. This is the case even when analyzing data for specific species/regions. For a more advanced and process-based understanding of changes in the water balance with changing forest structure, we examined transpiration (E) observed using the sap-flux method for 14 Japanese cedar and cypress plantations with various structure (e.g., stem density and diameter) in Japan and surrounding areas and developed a model relating E with structural parameters. We expressed E using the simplified Penman-Monteith equation and modeled canopy conductance (Gc) as a product of reference Gc (Gcref) when vapor pressure deficit is 1.0. kPa and functions expressing the responses of Gc to meteorological factors. We determined Gcref and parameters of the functions for the sites separately. E observed for the 14 sites was not reproduced well by the model when using mean values of Gcref and the parameters among the sites. However, E observed for the sites was reproduced well when using Gcref determined for each site and mean values of the parameters of the functions among the sites, similar to the case when using Gcref and the parameters of the functions determined for each site. These results suggest that considering variations in Gcref among the sites was important to reproduce variations in E, but considering variations in the parameters of the functions was not. Our analysis revealed that Gcref linearly related with the sapwood area on a stand scale (A) and that A linearly related with stem density (N) and powers of the mean stem diameter (dm). Thus, we proposed a model relating E with A (or N and dm), where Gcref was calculated from A (or N and dm) and the parameters of the functions were assumed to be the mean values among the sites. This model estimates changes in E with changing structure from commonly available data (N and dm), and therefore helps improve our understanding of the underlying processes of the changes in the water balance for Japanese cedar and cypress plantations.. |
| 16. | Ayumi Katayama, Tomonori Kume, Hikaru Komatsu, Mizue Ohashi, Kazuho Matsumoto, Ryuji Ichihashi, Tomo'Omi Kumagai, Kyoichi Otsuki, Vertical variations in wood CO2 efflux for live emergent trees in a Bornean tropical rainforest, Tree physiology, 10.1093/treephys/tpu041, 34, 5, 503-512, 2014.05, [URL], Difficult access to 40-m-tall emergent trees in tropical rainforests has resulted in a lack of data related to vertical variations in wood CO2 efflux, even though significant variations in wood CO2 efflux are an important source of errors when estimating whole-tree total wood CO2 efflux. This study aimed to clarify vertical variations in wood CO2 efflux for emergent trees and to document the impact of the variations on the whole-tree estimates of stem and branch CO2 efflux. First, we measured wood CO2 efflux and factors related to tree morphology and environment for seven live emergent trees of two dipterocarp species at four to seven heights of up to ~40 m for each tree using ladders and a crane. No systematic tendencies in vertical variations were observed for all the trees. Wood CO2 efflux was not affected by stem and air temperature, stem diameter, stem height or stem growth. The ratios of wood CO2 efflux at the treetop to that at breast height were larger in emergent trees with relatively smaller diameters at breast height. Second, we compared whole-tree stem CO2 efflux estimates using vertical measurements with those based on solely breast height measurements. We found similar whole-tree stem CO2 efflux estimates regardless of the patterns of vertical variations in CO2 efflux because the surface area in the canopy, where wood CO2 efflux often differed from that at breast height, was very small compared with that at low stem heights, resulting in little effect of the vertical variations on the estimate. Additionally, whole-tree branch CO2 efflux estimates using measured wood CO2 efflux in the canopy were considerably different from those measured using only breast height measurements. Uncertainties in wood CO2 efflux in the canopy did not cause any bias in stem CO2 efflux scaling, but affected branch CO2 efflux.. |
| 17. | Yoshinori Shinohara, Tomonori Kume, Ryuji Ichihashi, Hikaru Komatsu, Kyoichi Otsuki, Moso-bamboo forests in Japan What are the effects of their area expansion on ecosystem services?, Nihon Ringakkai Shi/Journal of the Japanese Forestry Society, 96, 6, 351-361, 2014.01, Recently, mosobamboo (Phyllostachys pubescens) forests have been expanding in Japan. Some studies have pointed out their expansion could decrease ecosystem services. This paper summarized expansion rates in areas in the last ca. 70 years and biomass of moso-bamboo forests. We verified whether the expansions could increase risks in flood, water shortage, shallow landslide, and soil erosion. Many papers have reported increases in areas of moso-bamboo forests, and the average expansion rate was 1.03 ha/ha year. The rate in the surrounding open spaces tends to be larger than that in the surrounding closed spaces. Aboveground biomass in moso-bamboo forests was between 62.6 and 224.3 t/ha. The maximum aboveground biomass in moso-bamboo forests would be smaller than those in Japanese cedar (Cryptomeria japonica) and Japanese cypress (Chamaecyparis obtusa) forests. However, only a few studies examined belowground biomass in moso-bamboo forests. As well, based on results in previous studies, we concluded that risks in flood, water shortage, shallow landslide, and soil erosion in moso-bamboo forests would not be higher than those in other types of forests. This conclusion is different from the speculation. On the other hand, this conclusion was based on only a few studies. Therefore, further studies are required to clarify various processes related to flood, water shortage, shallow landslide, and soil erosion in moso-bamboo forests with various canopy structures under various meteorological conditions.. |
| 18. | Hironori Toyama, Hiroki Itadani, Makiko Tateishi, Yuuya Tachiki, Keiko Mase, Yusuke Onoda, Nobuya Mizoue, Hidenori Tachida, Tetsukazu Yahara, Shuichiro Tagane, Phourin Chhang, Tsuyoshi Kajisa, Ryuji Ichihashi, Vanna Samreth, Ma Vuthy, Heng Sokh, Ayumi Katayama, Inventory of the Woody Flora in Permanent Plots of Kampong Thom and Kampong Chhnang Provinces, Cambodia, Acta Phytotaxonomica et Geobotanica, 10.18942/apg.KJ00008877422, 64, 2, 45-105, 2013.08, [URL], To improve our knowledge of the woody flora of Cambodia, we collected specimens of trees, shrubs and woody vines within and near permanent plots of evergreen and deciduous tropical forests in lowland Cambodia. We sequenced rbcL and matK for most specimens, searched for species having high homologies with those sequences and then identified the collections using taxonomic literature and herbarium specimens. As a result, we identified 325 species in 69 families, including 163 trees, 90 shrubs, 67 vines, four palms and an epiphytic parasite. The frequencies of correct identification of BLAST searched sequences were low at the species level (about 15%), but high at the family and generic levels (about 100% and 75%, respectively). Twenty-one species were new to Cambodia. We corrected many previous misidentifications in the plot records.. |
| 19. | Ayana Miyashita, Daisuke Sugiura, Koichiro Sawakami, Ryuji Ichihashi, Tomokazu Tani, Masaki Tateno, Long-term, short-interval measurements of the frequency distributions of the photosynthetically active photon flux density and net assimilation rate of leaves in a cool-temperate forest, Agricultural and Forest Meteorology, 10.1016/j.agrformet.2011.08.001, 152, 1, 1-10, 2012.01, [URL], Long-term, short-interval measurements of incident photosynthetically active photon flux density (PPFD; μmolm-2s-1) on the forest floor are essential for estimating the leaf carbon gain of understory plants. Such PPFD data, however, are scarce. We measured PPFD at 1-min intervals for more than 12months in cool-temperate forest sites and reported the data as a PPFD frequency distribution. We chose five sites: an open site (OPN), the understory of a deciduous broad-leaved tree stand with no visible gaps (DCD), that of an evergreen conifer stand (EVG), that of a deciduous broad-leaved tree stand with a gap of approximately 80m2 (GAPDCD), and that of an evergreen conifer stand with a gap of approximately 100m2 (GAPEVG). DCD were divided into three sub sites (DCD1-3) to investigate variation within a small area. GAP-sites were consisted of two sub sites (GAPDCD1-2 and GAPEVG1-2) differing in the distance from the gap center. Using the PPFD data, we estimated the summer seasonal (May-October) net assimilation rate of leaves (NARL) at each site for various photosynthetic capacities (Amax: μmolm-2s-1) and other parameters of a light response curve of CO2 assimilation rates. At OPN, the average daily accumulated PPFD (molm-2day-1) was highest in May (28.2) and lowest in December (8.2). Even at OPN, the class of instantaneous PPFD that contributed most to NARL was 250-300μmolm-2s-1. Such a large contribution of lower PPFD is suggested to be an important feature of a field light-availability. At DCD, the relative PPFD (RPPFD, %) to OPN was 7.2 during canopy closure and 49.4 after leaf shedding (averaged for 3 sites). EVG had the lowest light environment throughout the year. Its average RPPFD was 3%. For GAP sites, summer seasonal RPPFD (%) was 15.6, 18.8, 6.4 and 15.6 for GAPDCD1, GAPDCD2, GAPEVG1 and GAPEVG2, respectively. At OPN, the NARL increased with Amax (which ranged from 1 to 40), suggesting that plants at OPN do not maximize NARL. In contrast, at DCD and EVG, Amax values were attained that did maximize NARL, suggesting that plants at these sites could maximize the NARL. Amax-NARL relationships for GAPDCD and GAPEVG showed similar trend to closed canopy sites, DCD and EVG, while NARL x of GAP sites were larger than at these sites. Among DCD1-3, the daily accumulated PPFD (molm-2 day-1) averaged in summer ranged 1.3-1.8 and the maximum NARL value differed up to 1.5 times. It indicates that Amax and NARL can be various among plants under a similar canopy conditions.. |
| 20. | 鶴田健二，小松光，篠原慶規，久米朋宣 ，市橋隆自，大槻恭一, 樹液流計測に基づいたスギとヒノキの林分蒸散量算定のための辺材面積推定式, 水文・水資源学会誌, 24, 5, 261-270, 2011.09. |
| 21. | Ryuji Ichihashi, Masaki Tateno, Strategies to balance between light acquisition and the risk of falls of four temperate liana species To overtop host canopies or not?, Journal of Ecology, 10.1111/j.1365-2745.2011.01808.x, 99, 4, 1071-1080, 2011.07, [URL], 1.Lianas face a dilemma: how can they achieve a balance between the benefits they gain from light capture in their host canopies and the risk of falls resulting from the deleterious effects they have on the growth and survival of their host trees? To address this issue, we investigated leaf distribution patterns, canopy dynamics and the impact of four liana species on the growth of their hosts. 2.In the forest canopy, the majority of the leaves of Actinidia arguta (Actinidiaceae) received >80% irradiance relative to the canopy top. The leaf mass and the length of the canopy framework of this species increased linearly with time after it had reached the forest canopy (estimated from the number of growth rings in the main liana stem at 8m height). In contrast, a much lower percentage irradiance was received by leaves of the three other species, Celastrus orbiculatus (40-80%, Celastraceae), Schisandra repanda ( |
| 22. | Ryuji Ichihashi, Hisae Nagashima, Masaki Tateno, Biomass allocation between extension- and leaf display-oriented shoots in relation to habitat differentiation among five deciduous liana species in a Japanese cool-temperate forest, Plant Ecology, 10.1007/s11258-010-9783-0, 211, 1, 181-190, 2010.10, [URL], Liana species have a variety of habitat preferences. Although morphological traits connected to resource acquisition may vary by habitat preference, few studies have investigated such associations in lianas. In previous work on temperate lianas, we observed (1) free standing leafy shoots and (2) climbing shoots that clung to host plants; we examined relationships between habitat preference and shoot production patterns in five liana species. Among the five species, two were more frequent at the forest edges (forest-edge species), and two were more common within the forests (forest-interior species). The proportion of climbing shoots in current-year shoot mass of young plants (3-8 m in height) was greater in the forest-edge species (45-60%) than in the forest-interior species (6-30%). In consequence, there was a greater leaf mass ratio in the total current-year shoots of forest-interior species. This, combined with a greater specific leaf area, endows forest-interior species with a leaf area per unit shoot mass double that of forest-edge species. Forest-edge species had longer individual climbing shoots whose length per unit stem mass was smaller than in forest-interior lianas. Extension efficiency, measured as the sum of the climbing stem length per unit current-year shoot mass, was thus similar between forest-edge and interior species. In conclusion, liana shoot production patterns were related to species habitat preferences. A trade-off between current potential productivity (leaves) and the ability to search for hosts and/or well-lit environments (climbing stems) may underpin these relationships.. |
| 23. | Ryuji Ichihashi, Hisae Nagashima, Masaki Tateno, Morphological differentiation of current-year shoots of deciduous and evergreen lianas in temperate forests in Japan, Ecological Research, 10.1007/s11284-008-0512-2, 24, 2, 393-403, 2009.03, [URL], Morphological variation in current-year shoots within plants was examined in five deciduous and four evergreen liana species from temperate forests in Japan to elucidate the role differentiation in shoots. All lianas had both shoots that twined or developed adventitious roots to gain support on host materials (searcher shoots) and self-supporting shoots with no climbing structures (ordinary shoots). Searcher shoots were 20-295 times longer than ordinary shoots. The allometric relationships between stem length and leaf area differed between searcher and ordinary shoots, and the stem length for a given leaf area was greater in searcher shoots. Leaf area per shoot mass was 1.4-4.3 times higher in ordinary shoots because of the greater allocation to leaf biomass. Searcher shoots comprised only 1-6% of total shoots but 30-85% of total shoot length in deciduous lianas. Ordinary shoots accounted for 70-95% of the total leaf area in these liana species. These results suggest that the exploration of new space was primarily achieved by searcher shoots, whereas a large proportion of current photosynthetic production was achieved by ordinary shoots. The range of stem length and leaf mass ratio of ordinary shoots was similar to that in shoots of tree species. Specialization of shoots in lianas is discussed.. |
| 24. | Satoshi Yoshida, Ryuji Ichihashi, Akio Toh-e, Ras recruits mitotic exit regulator Lte1 to the bud cortex in budding yeast, Journal of Cell Biology, 10.1083/jcb.200301128, 161, 5, 889-897, 2003.06, [URL], ACdc25 family protein Lte1 (low temperature essential) is essential for mitotic exit at a lowered temperature and has been presumed to be a guanine nucleotide exchange factor (GEF) for a small GTPase Tem1, which is a key regulator of mitotic exit. We found that Lte1 physically associates with Ras2-GTP both in vivo and in vitro and that the Cdc25 homology domain (CHD) of Lte1 is essential for the interaction with Ras2. Furthermore, we found that the proper localization of Lte1 to the bud cortex is dependent on active Ras and that the overexpression of a derivative of Lte1 without the CHD suppresses defects in mitotic exit of a Δlte1 mutant and a Δras1 Δras2 mutant. These results suggest that Lte1 is a downstream effector protein of Ras in mitotic exit and that the Ras GEF domain of Lte1 is not essential for mitotic exit but required for its localization.. |
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