| Project/Area Number |
07456119
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
生物環境
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| Research Institution | TOKYO UNIVERSITY OF AGRICULTURE |
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Principal Investigator |
NAGANO Toshihide Tokyo University of Agriculture Prof., 農学部, 教授 (10012006)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIDA Tomoyasu Utsunomiya University Associate Prof., 農学部, 助教授 (00159740)
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| Project Period (FY) |
1995 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1997: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1996: ¥700,000 (Direct Cost: ¥700,000)
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| Keywords | ROOT / PERMEABILITY / WATER / TEMPERATURE / SPAC / 13ﾟC / 根の水透過特性 / 根の養分透過特性 / 根の通水抵抗 / 通水抵抗の測定方法 / 根のイオン透過特性 / 人工根 / 温度と通水抵抗 / 吸水抵抗 / 通導抵抗 |
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| Research Abstract |
The effect of thermal factors on resistance to water flow through soybean root system was measured. Total resistance of root system are divided to absorptive (radial) resistance and conductive resistance (=longitudinal) one. The total resistance increases with similar rate to water viscosity as temperature in root system decreases above 13ﾟC . While, the toal resistance increases sharply as temperature decreases below 13ﾟC.Thus, the principla cause of the increase in total resistance over 13ﾟC is the temperature dependency of water viscosity. However the principle cause is the change of permeability of cell membrane itself below 13ﾟC.
The conductive resistance changes with similar rate to water viscosity as temperature changes in any range. The absorptive resistance changes with similar rate to water viscosity as temperature changes above 13ﾟC C to 23ﾟC.While, it increases sharply as temperature decreases below 13ﾟC.Thus, the temperature, 13ﾟC,is the threshold for water permeability of soybean root membrane and the change in the permeability seems to be the main cause of the sharp change of the total resistance.
The contributing ratio of the absorptive resistance to the total resistance is almost constant at 75% from 13ﾟC to 23ﾟC,while the ratio increases sharply and increases up to 90% at 8ﾟC.The conductive resistance in xylem cannot neglect at any temperature for normal growing condition of soybean. Temperature dependency of both absorptive and conductive resistance must be taken into account to simulate the water flux through SPAC.
In this research, we focused on lower temperature condition. Similar threshold could exist in higher temperature condition and should be found out. Also, the relation between appropriate temperature for plant growth and these thresholds should be found out. The research could make it clear what the proper temperature for plant growth means.
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