2001 Fiscal Year Final Research Report Summary
Study on the development of an easy evaluation method of root system activity changes with time and the optimum dry matter partitioning to root
| Project/Area Number |
11660016
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
作物学
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| Research Institution | Shinshu University |
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Principal Investigator |
HAGIWARA Motoyuki Shinshu University, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (90172840)
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| Co-Investigator(Kenkyū-buntansha) |
INOUE Naoto Shinshu University, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (80232544)
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| Project Period (FY) |
1999 – 2001
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| Keywords | paddy rice / common buckwheat / root system / root respiration rate / root dry / fresh weight ratio / new-root sampling |
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| Research Abstract |
Experiment was conducted to compare direct seeding in well-drained paddy field and transplanting using paddy rice cultivar Koshihikari. Analysis was also performed on the data obtained from dry seeding in upland and transplanting in lowland field using tropical rice cultivars in the Philippines. Root samples were collected just in between 2 hills in a row in all experiments.
1. Analysis of root growth dynamics in Koshihikari
Whole-root dry weight recorded a maximum after heading in direct-seeding and at panicle initiation in transplanting. Dry-weight growth rate of new root recorded a maximum at panicle initiation both in direct-seeding and transplanting. The percentage of dead root in direct-seeding was lower than in transplanting during the early growth stage, while the percentage of new root was about the same in direct-seeding and transplanting. Therefore, it seemed that roots of transplanted rice have shorter life which resulted in accelerated turn over of roots and that roots of di
… More
rect-seeded rice have longer life which resulted in later appearance of a maximum whole-root weight.
2. Analysis of root growth dynamics in tropical rice
Maximun new-root growth rate was observed at panicle initiation in lowland field and before panicle initiation in upland field. Maximum new-root growth rate in upland cultivars in upland field was higher than lowland ones in lowland field. The amount and rate of dead root were 90-160gm-2 and 53-78 %, respectively.
3. Easy evaluation of root respiration rate
Further data accumulation for the development of an easy evaluation of root respiration rate by root dry/fresh weight ratio was conducted. Root dry/fresh weight ratio was demonstrated to be a good index for the evaluation of root respiration rate both for direct-seeded and transplanted Koshihikari. Similarly, root respiration rate correlated well with dry/fresh weight ratio in tropical rices both under upland and lowland conditions. Thus, root dry/fresh weight ratio was suggested to be a good index for the easy evaluation of root respiration rate. Less
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