The Reversible Reaction of Auxin in Root Gravitropism and the Role of Calcium
| Project/Area Number |
12640626
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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 |
植物生理
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| Research Institution | Yamagata University |
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Principal Investigator |
SUZUKI Takashi Yamagata University, Faculty of Education, Professor, 教育学部, 教授 (70134145)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2001: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2000: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Auxin / Calcium / Cell Wall / Gravitropism / IAA / Signaling / Root / 信号伝達系 |
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| Research Abstract |
Our attention was focused on the reaction linking between the transduction and the transmission in root gravitropism. We found that the elevation of contents of free Ca^<2+> in the apoplast of root tips, the basipetal transport of diffusible IAA and the decrease of contents of cell wall-bound IAA in the root tips, were brought about by gravistimulation, and also observed that the tips of the non-gravistimulated roots did not contain the contents of diffusible IAA moving basipetally from root tips to regions of elongation. These results lead to the idea that the transportable IAA may result from the dissociation of cell wall-bound IAA to free IAA in the apoplast of the gravistimulated root tips, and that Ca^<2+> may be involved in the dissociation of IAA from bound to free.
To study the correlation between Ca^<2+> and the reversible reaction of IAA, we examined the effects of EGTA and CaCl_2 on the content of alkali-extractable IAA (as bound IAA) in cell wall of 0-1-mm sections of the primary roots (Zea mays L. cv. Golden Cross Bantam 70). EGTA produced elevation of the content of the bound IAA. When the sections were treated with CaCl_2 after EGTA, the content of the bound IAA decreased. Furthermore, we found that EGTA and CaCl_2 had the same effect to cell wall fraction prepared from 0-1-mm sections of the primary roots. These results indicate that the dissociation of the cell wall-bound IAA to free IAA was regulated by Ca^<2+> .
We proposed the involvement of the reversible reaction of IAA in the signaling processes of gravity in root gravitropism.
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Report
(3 results)
Research Products
(11 results)
