|Toshihiko EGUCHI||Last modified date：2023.04.05|
Associate Professor / Environmental Control Center for Experimental Biology
E-Mail *Since the e-mail address is not displayed in Internet Explorer, please use another web browser:Google Chrome, safari.
Reseacher Profiling Tool Kyushu University Pure
Country of degree conferring institution (Overseas)
Field of Specialization
Environment Control for Biology, Horticultural Science
Total Priod of education and research career in the foreign country
Environmental factors such as temperature, humidity and light intensity strongly affect crop productivity. To make an optimal condition for crop production, I am working on the elucidation of environmental effects on the growth and development of storage organs in crop plants, especially in sweetpotatoes. A storage root, or a tuberous root, of sweetpotato is a root having a region of localized thickening, and the storage organ grows below ground. I developed a new method for on-line measurement of diurnal change in tuberous root growth under the controlled environments. This system is also applicable for the growth analysis of potato tuber. By using the system, I found that the tuberous root growth was affected by humidity condition of the shoot through leaf transpiration. Temperature condition of the fibrous root also had a strong effect on the tuberous root growth as well as tuberous root temperature. Furthermore, I am trying to elucidate the mechanism of the tuberous root formation. I have already obtained the cultivation technique that ensures the formation of the storage organ in a specific part of a specific root. I am searching exogenous and endogenous factors required for the tuberous root formation using the technique now.
Research InterestsMembership in Academic Society
- Analyses of environmental effects on translocation and storage of photoassimilates in plants
keyword : plant, photoassimilates, translocation, storage, morphogenesis, environment control, measurement techniques in biology, sink-source relationship
1989.04Analyses of environmental effects on translocation and storage of photoassimilates in plants: Environmental factors such as temperature, humidity and light intensity strongly affect crop productivity. To make an optimal condition for crop production, I am working on the elucidation of environmental effects on the growth and development of storage organs in crop plants..
|1.||Toshihiko EGUCHI, Takuya ARAKI, Masaharu KITANO, Non-contact Measurements of Storage Organ Growth in Fruit and Root Crops., Environment Control in Biology, Volume 45, Number 4, p.251-258., 2007.12.|
|1.||Toshihiko EGUCHI, Hiroyuki TANAKA, Mayuki SAGAWA, Satoshi YOSHIDA and Ken MATSUOKA, Time-course Pattern of Growth of the Medicinal Plant Pinellia ternata Breit. Grown under Controlled Environments
, Environmental Control in Biology, DOI: 10.2525/ecb.60.191, 60, 4, 191-194, 2022.10, To obtain the typical growth pattern of the medicinal plant Pinellia ternata Breit., we investigated the growth of plants grown under constantly controlled environments (air temperature: 25℃, air humidity: 70%RH, day length: 12h, light intensity: 220μmol photon m-2 s-1 (PPFD) ). The growth pattern was comparable with other plant growth patterns grown under different environmental conditions. Leaf number, leaf area, and corm weight of the plants increased over time, while dry matter content in the corm maintained at approximately 35% during cultivation. Cormlets born on the corm increased linearly during cultivation, and the weight increased significantly after 11 weeks of cultivation. The content of araban, the effective ingredient of the corm, increased linearly until 11 weeks of cultivation, after which, the content appeared to level off. Thus, we obtained the typical growth pattern of the P. ternata, which is useful for evaluating the environmental effects on the plant productivity..
|2.||Toshihiko EGUCHI, Hiroyuki TANAKA, Satoshi YOSHIDA and Ken MATSUOKA, Effects of Nutrient Solution Electrical Conductivity and pH on the Productivity of the Medicinal Plant Pinellia ternata Breit., Environmental Control in Biology, DOI: 10.2525/ecb.60.149, 60, 2, 149-151, 2022.04, Medicinal plants (Pinellia ternata Breit.) were cultivated under four nutrient solution conditions, namely a pH of 4 and electrical conductivity (EC) of 2.2 mS cm-1, pH of 4 and EC of 1.2 mS cm -1, pH of 6 and EC of 2.2 mS cm-1, and pH of 6 and EC of 1.2 mS cm-1. Plants were grown for 15 weeks in phytotron glass rooms controlled at an air temperature of 25 °C and a relative humidity of 70 %. The leaf number per plant was measured every week, the leaf chlorophyll content (SPAD) was measured at 100 d after planting, and the corm yield and the effective ingredient, namely araban, content in the corm were evaluated after 15 weeks of cultivation. No clear effects of the nutrient solution EC and pH on the corm growth, the corm quality, and leaf chlorophyll content were not observed in this experiment. The EC and pH of the nutrient solution will not affect the productivity of the P. ternate in the ranges of EC 1.2 – 2.2 mS cm-1 and pH 4 – 6, respectively..|
|3.||Toshihiko EGUCHI, Hiroyuki TANAKA, Daichi Moriuchi, Satoshi YOSHIDA and Ken MATSUOKA, Temperature Effects on the Photosynthesis by the Medicinal Plant Pinellia ternata Breit., Environmental Control in Biology, DOI: 10.2525/ecb.58.49, 58, 2, 49-50, 2020.04, We investigated the effect of air temperature on the growth of the medicinal plant Pinellia ternata Breit. collected from the four prefectures, Fukushima, Kyoto, Nagasaki, and Okinawa prefectures. Plants were grown for 15 weeks in phytotrons controlled at air temperatures of 20, 25, and 30 ̊C. In the Kyoto lines, the highest corm yield was observed at 25 ̊C, whereas the corm yields in Fukushima, Nagasaki, and Okinawa lines did not differ significantly with respect to yield among the three growth temperature conditions. Therefore, in this study, the temperature effects on the photosynthesis by P. ternata collected from the three prefectures of Kyoto, Nagasaki, and Okinawa were investigated. Obvious effects of air temperatures were not observed in the plant photosynthesis for all regions. Thus, air temperature does not affect the yield through the photosynthesis in the P. ternata..|
|4.||Toshihiko EGUCHI, Hiroyuki TANAKA, Satoshi YOSHIDA and Ken MATSUOKA, Temperature Effects on the Yield and Quality of the Medicinal Plant Pinellia ternata Breit., Environmental Control in Biology, DOI: 10.2525/ecb.57.83, 57, 3, 83-85, 2019.07, The medicinal plant Pinellia ternata Breit., which is a non-domesticated plant, is widely distributed in Japan. However, the crude drug made from the plant corm is not currently produced in Japan. We investigated the influences of air temperature on the growth of P. ternata collected from 2 regions, the Kyoto and Nagasaki prefectures, for both of summer and winter seasons. The temperature effects on the effective ingredient contents in the corms were also investigated. At Kyushu University, plants were grown for 15 weeks in phytotron glass rooms controlled at air temperatures of 20, 25, or 30°C. The corm yields and effective ingredient content in the winter cultivation were poorer than those in the summer, because the cumulative solar radiation during the winter cultivation period was almost half of that in the summer. In the Kyoto lines, the highest corm yield was obtained at 25℃ in the summer cultivation, while the Nagasaki lines did not show significant differences with respect to yield among the three growth temperature conditions. The effective ingredient contents in the corm did not differ significantly among the three temperature conditions for both lines, although the amount of effective ingredient in the Kyoto lines were significantly higher than those of Nagasaki in summer cultivation..|
|5.||Eguchi, T., Satoshi YOSHIDA, Time-course Pattern of Electrolyte Leakage from Tuberous Roots of Sweetpotato (Ipomoea batatas (L.) Lam.) after Short-term High Temperature, Environmental Control in Biology, http://doi.org/10.2525/ecb.54.183, 54, 4, 183-185, 2016.10, We investigated the time-course pattern of electrolyte leakage from the root flesh of growing tuberous roots of two sweetpotato cultivars, Koganesengan and Narutokintoki, after exposing them to high temperature for short duration. For both cultivars, the electrolyte leakage after 1 h of treatment was significantly higher than that at 24 h after treatment. This pattern was similar to the pattern observed following instantaneous flooding treatment previously reported by us. Electrolyte leakage from plant cells is an indicator of cellular responses to various stress factors. Similar stress, therefore, might be caused in heated and flooded tuberous roots..|
|6.||Eguchi, T., Ito, Y., Satoshi YOSHIDA, Instantaneous Flooding and α-Tocopherol Content in Tuberous Roots of Sweetpotato (Ipomoea batatas (L.) Lam.), Environmental Control in Biology, 53, 1, 13-16, 2015.03, Compared to sub-irrigated sweetpotatoes (Ipomoea batatas (L.) Lam.), periodic surface-irrigated plants, i.e., twice a week on root media, showed increased α-tocopherol content in their tuberous roots with no apparent changes in both of tuberous root development and oxygen concentration around the roots. We speculated that surface irrigation might temporarily cover the tuberous root surface with water and inhibit oxygen movement into the roots, thereby increasing the antioxidant α-tocopherol content, for coping with the slight oxidative stress occurring within the roots. Therefore, we performed 1-3 times instantaneous flooding, with different intervals, which perfectly covered the whole root surface with water, of sweetpotato plants grown in a phytotron glass room (25℃, 70%RH). Electrolyte leakage from the tuberous root flesh cells showed a temporal increase for the flooding treatment, while it immediately recovered within 24 h. Instantaneous flooding did not affect the storage root development in any of the experiments. Apparent increases in the α-tocopherol content were observed during the 3-time flooding at 3-day intervals. Our results suggest that more frequent root surface wetting is necessary for increasing the α-tocopherol content, which is released because of the oxidative stress that occurs within the roots..|
|7.||江口 壽彦, 田中 宏幸, 吉田 敏, 松岡 健, Influence of Ground Water Level on the Growth of the Medicinal Plant Pinellia ternata Breit. in a Solid Substrate Culture System, The international conference on plant factory 2014, 2014.11, Many crude drugs used in Kampo medicines in Japan represent untapped medicinal resources. Domestication of the wild plants from which these drugs are derived and preservation of their natural habitats are necessary for establishing a stable supply of Kampo medicines. Here, we investigated the influence of the moisture condition of root medium on the growth of Pinellia ternata Breit. by using a sub-irrigation solid substrate culture system. The moisture condition was controlled by maintaining a constant ground water level (GWL). Plants were grown for 15 weeks under a GWL of either 4 cm (GWL-4) or 8 cm (GWL-8) below the corm base in a phytotron glass room at 25°C and 70% relative humidity. The water content of the root media around the corm in GWL-4 was only 1% higher than that in GWL-8. However, water content apparently affected corm enlargement and the development of new bulbils. Relative yield of the corm per plant, compared with the initial weight, was ~400% in GWL-4 and ~200% in GWL-8. The number of bulbils produced in a plant was 13.5 in GWL-4 and 4.4 in GWL-8. The effective ingredient, a kind of water-soluble polysaccharide consisting mainly of arabinose, was about 10% higher in GWL-8 corms than in GWL-4 corms. Moreover, when comparing the two conditions, the relative difference in corm yield was remarkably larger than that observed for the effective ingredient content. Overall, productivity was considered to be higher in GWL-4 than in GWL-8..|
|8.||Toshihiko EGUCHI, Yuji ITO and Satoshi YOSHIDA, Periodical Wetting Increases α-Tocopherol Content in the Tuberous Roots of Sweetpotato (Ipomoea batatas (L.) Lam.), Environment Control in Biology, 50, 3, 297-303, 2012.09, Tuberous root growth and antioxidant contents of 2 sweetpotato (Ipomoea batatas (L.) Lam.) cultivars were examined using 2 different irrigation schemes: surface-irrigation and sub-irrigation. Coarse silica sand was used for root media, which maintained well the gas permeability and water drainage around the roots. The root surface was periodically wetted for watering in the surface-irrigated roots, while the sub-irrigated roots were not. The irrigation methods did not affect the oxygen concentration around the roots. No differences in plant growth were observed between the 2 irrigation methods. However, the content of α-tocopherol in the tuberous root was significantly higher in the ordinary-irrigated roots for both of two cultivars. Thus, the periodical wetting increased the α-tocopherol content in the tuberous root of sweetpotato cultivars without any apparent changes in tuberous root development..|
|9.||Toshihiko EGUCHI, Takehiko SUZUKI, Satoshi YOHSIDA, Ikuo MIYAJIMA, Masaharu KITANO, Time-course Pattern of Carrot Storage Root Growth in a Solid Substrate, Sub-irrigation Culture System, Environment Control in Biology, 49, 4, 177-183, 2011.12.|
|10.||Toshihiko EGUCHI, Satoshi YOSHIDA, Tuberous Root Thickening: A Rapid Response to Hypoxia in Sweetpotato (Ipomoea batatas (L.) Lam.), Environment Control in Biology, 49, 1, 47-50, 2011.03.|
|11.||T. Eguchi, T. Suzuki, H. Miyamoto, M. Hamakoga, S. Yoshida, J. Chikushi and M. Kitano. Influence of Ground Water Level on Carrot Growth in Solid Substrate Culture System. Journal of Science and High Technology in Agriculture (J. SHITA) 21(2): 65-71..|
|12.||Toshihiko EGUCHI, Satoshi YOSHIDA , Effects of Application of Sucrose and Cytokinin to Roots on the Formation of Tuberous Roots in Sweetpotato (Ipomoea batatas (L.) Lam.), Plant Root, Volume 2, p. 7-13, 2008.03, [URL].|
|13.||T. Eguchi, S. Moriyama, I. Miyajima, S. Yoshida and J. Chikushi A Hydroponic Method Suitable for Tops Production of a Sweetpotato Cultivar 'Suioh'. Journal of Science and High Technology in Agriculture (J. SHITA) 19(4): 167-174..|
|14.||Toshihiko EGUCHI, Satoshi YOSHIDA, Effects of gas exchange inhibition and hypoxia on tuberous root morphogenesis in sweetpotato (Ipomoea batatas (l.) Lam.)., Environment Control in Biology, Volume 45, No. 2, p. 103-111, 2007.06.|
|15.||T. Eguchi and S. Yoshida, A Cultivation Method to Ensure Tuberous Root Formation in Sweetpotatoes (Ipomoea batatas (l.) Lam.)., Environment Control in Biology, Vol. 42(4): 259-266, 2004.12.|
|16.||T. Eguchi, T. Araki, S. Yoshida and M. Kitano, Xylem Sap Backflow from Tomato Fruit under Water Deficit Condition, Acta Horticulturae, 618, 347-351, Vol. 618: 347-351, 2003.12.|
|17.||T. Eguchi, M. Kitano, S Yoshida and J. Chikushi, Root temperature effects on tuberous root growth of sweetpotato (Ipomoea batatas Lam.) -Direct and indirect effects of temperature-, Environment Control in Biology 41(1):43-49, 2003..|
|18.||T. Araki, M. Kitano, K. Okano, S. Yoshida and T. Eguchi, Environmental effects on dynamics of fruit growth and photoassimilate translocation in tomato plants (3) -Effect of salt stress-, Environment Control in Biology 39(1):53-58, 2001..|
|19.||T. Eguchi, A new method for on-line measurement of diurnal change in potato tuber growth under controlled environments, Journal of Experimental Botany, 10.1093/jexbot/51.346.961, 51, 346, 961-964, Vol. 51(346): 961-964, 2000.05.|
|20.||M. Kitano, T. Araki, S. Yoshida and T. Eguchi, Dependence of calcium uptake on water absorption and respiration in roots of tomato plants (Lycopersicon esculentum Mill.), Biotronics, Vol. 28: 121-130, 1999.12.|
|21.||T. Eguchi, M. Kitano and H. Eguchi, Growth of tuberous root as affected by the ambient humidity in sweetpotato (Ipomoea batatas Lam.), Environment Control in Biology 37(3):197-201, 1999..|
|22.||T. Eguchi, M. Kitano and H. Eguchi, Water relations and dynamics of tuber growth rate in sweet potato plants (Ipomoea batatas Lam.), Environment Control in Biology 36(2):91-95, 1998..|
- The Crop Science Society of Japan
- The Japanese Society of Agricultural, Biological and Environmental Engineers and Scientists
- The Japanese Society for Horticultural Science
- Japanese Society for Root Research
- International Society for Horticultural Science
- Water and carbon balance in developing fruit of the satsuma mandarin (Citrus unshiu Mare.). Environmental Control in Biology Vol. 50(2): 189-198.
- Kinetics of root ion absorption affected by environmental factors and transpiration. Environment Control in Biology Vol. 49(1): 41-46.
Unauthorized reprint of the contents of this database is prohibited.