1995 Fiscal Year Final Research Report Summary
EFFECTS OF ROOT TEMPERATURE ON GROWTH OF CROP PLANTS
| Project/Area Number |
06454050
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
作物学
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| Research Institution | ARID LAND RESEARCH CENTER,TOTTORI UNIVERSITY |
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Principal Investigator |
INANAGA Shinobu ARID LAND RESEARCH CENTER,PROFESSOR, 乾燥地研究センター, 教授 (40124664)
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| Co-Investigator(Kenkyū-buntansha) |
SUGIMOTO Yukihiro ARID LAND RESEARCH CENTER,ASSISTANT PROFESSOR, 乾燥地研究センター, 助教授 (10243411)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Root temperature / Tomato / Growth / Transpiration / Nutrient uptake / Xylem sap / Cytokinin / Gibberellin |
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| Research Abstract |
Response of tomato (Lycopersicon esculuntum) supplied with vary ratios of nitrate/ammonium to constant and variable low root temperature were studied. Root temperatures (12/12,16/8 and 20/20ﾟC day/night) were set for tomato, where other environmental conditions were constant. The effects of low root temperature on transpiration, growth, ionic balance of total and of water soluble mineral elements, soluble carbohydrates and nutrient concentration as well as gibberellins and cytokinin levels in xylem sap are determined.
Tomato results showed that low day root temperatures of 12 and 16ﾟC reduced, significantly, the transpiration and growth (shoot dry weight by 47 and 26%, root dry weight by 36 and 14%, shoot nitrate by 79 and 50%, root nitrate by 49 and 16%, levels of cytokinins in root xylem exudate by 27 and 13% and gibberellins by 65 and 23%) in relation to the respective values of 20ﾟC day root temperature. Soluble carbohydrates in the shoot and roots were increased significantly (18 a
… More
nd 111%) by 12ﾟC root temperature. In conclusions root temperature regime affects tomato growth by its influence. In conclusions root temperature regime affects tomato growth by its influence on various growth parameters. Fluctuating root temperature in the range 8 to 16ﾟC is more favorable for tomato growth than constant root temperature at the same average of 12ﾟC.The temperature effect can not be explained, only, on the basis of nutrient transport or nitrogen metabolism. Water uptake problems, due to changes in water viscosity and membrane permeability, has a direct effect on stomatal closure. Cytokinin and gibberellin production in the root is lower at low than at high root temperatures. Hormones transport from the root to the shoot is controlled by the actual root temperature during day and night and not the average root temperature. The main effects of low root temperatures on shoot growth stem from slow transport of plant hormones and nitrate to the top rather than reduction in their rate of biosynthesis or entry to the root, respectively. Less
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