| Project/Area Number |
12460010
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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 |
作物学
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| Research Institution | Nagoya University |
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Principal Investigator |
IIJIMA Mario Nagoya University, Graduate School of Bioagricultural Sciences, Associate Professor, 大学院・生命農学研究科, 助教授 (60252277)
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| Co-Investigator(Kenkyū-buntansha) |
MORITA Shigenori Tokyo University, Graduate School of Agricultural Life Sciences, Professor, 大学院・農学生命科学研究科, 教授 (00143404)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥10,200,000 (Direct Cost: ¥10,200,000)
Fiscal Year 2002: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2001: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥4,900,000 (Direct Cost: ¥4,900,000)
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| Keywords | cell production rates / cell release / decapping / mucilage exudation / root cap / root border cell / soil compaction / soil mechanical impedance / トウモロコシ / ストレス耐性 |
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| Research Abstract |
Plant roots grown in compacted soils have to overcome the mechanical impedance of the soil to root elongation. The friction between soil and the growing root may be decreased by the layer of root border cells. We tried to evaluate the role of the root border cells to decreasing the soil mechanical impedance. In the series of experiment, we found the following:
1. For the first time, we quantified the rate of sloughing of root border cells in an abrasive growth medium. The number of maize root border cells increased as a result of compaction, from 1930 to 3220 d^<-1> per primary root. The whole of the cap surface area was covered with detached cells in compacted sand, compared with about 7% of the surface area in loose sand. 2. We developed an image analysis procedure to quantify cell locations in the median longitudinal section of root caps. Only 7% of cells in the outermost layer of the root were associated with the columella region of the cap. 3. Mechanical impedance slightly enhanced meristematic activities in the lateral region of the root cap. Cell production rates were 2,010 cells d^<-1> in compact and 1,570 cells d^<-1> in loose. 4. The presence of a root cap alleviates much of the mechanical impedance to root penetration, and enables roots to grow faster in compacted soils. 5. The contribution of root border cells to the reduction in soil resistance by the presence of root cap was 58%. 6. A technique was developed to separate root border cells from soil particles. The number of root border cells in wet soil was significantly greater than that in the dry soil.
In conclusion, the lubricating layer of root border cells decreases frictional resistance to soil penetration.
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