1992 Fiscal Year Final Research Report Summary
Analysis on Physiological Response of Crop to Salinity
| Project/Area Number |
02454042
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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
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| Research Institution | Okayama University |
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Principal Investigator |
TSUCHIYA Mikio Okayama Univ. Fac. of Agr. Associate Prof., 農学部, 助教授 (80127571)
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| Co-Investigator(Kenkyū-buntansha) |
OKI Yoko Okayama Univ. Fac. of Agr. Associate Prof., 農学部, 助教授 (30127550)
KUBOTA Naohiro Okayama Univ. Fac. of Agr. Associate Prof., 農学部, 助教授 (70033272)
OGO Tatsuo Okayama Univ. Emeritus Prof., 名誉教授 (40032536)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Salt stress / Rice plant / Salt tolerance / Constructive respiration / Non-structural carbohydrate / Transpiration stream concentration factor / Reverse osmosis / Silicic acid |
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| Research Abstract |
Rates of photosynthesis, respiration and transpiration as well as ion uptake were measured in different varieties with varying salt tolerance under salt stress condition in order to determine a physiological status of salt tolerance. Moreover, the status was created artificially to clear a possible cultivation management and a breeding direction.
The following results were obtained:
1. Partitioning of assimilate was estimated by using constructive respiration coefficient. A pronounced difference in non-structural carbohydrate accumulation was found among rice varieties.
2. Na^+ was highly excluded in salt tolerant varieties and the exclusion efficiency increased with the transpiration rate, but not with root respiration rate.
3. The exclusion system drived by transpiration operated on Cl^-, K^+, Li^+, Ca^<2+> and Mg^<2+>, and the efficiency increased with the radius of hydrated ion.
4. Na^+ was excluded around endodermis and the mechanism of this function was pointed out to be based on reverse osmosis drived by negative pressure in the xylem produced by transpiration.
5. The varietal difference of salt tolerance was well-understood in terms of the capacity of root as a reverse osmosis membrane and the transpiration ability as a driving power.
6. Salt tolerant variety had higher transpiration due to the osmotic adjustment of accumulated non-structural carbohydrate induced under salt condition, though its root capacity as a reverse osmosis membrane was originally lower.
7. An enrichment of silicic acid into the culture solution and a low NaCl concentration pretreatment increased Na^+ exclusion efficiency through the improvement of the membrane quality and driving power.
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