1998 Fiscal Year Final Research Report Summary
STUDIES ON THE ROLE OF VACUOLES IN ION METABOLISMS IN PLANT.
| Project/Area Number |
09044211
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Field |
植物生理
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| Research Institution | HITOTSUBASHI UNIVERSITY |
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Principal Investigator |
MIMURA Tetsuro HITOTSUBASHI UNIVERSITY FACULTY OF COMMERCE,PROFESSOR, 商学部, 教授 (20174120)
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| Co-Investigator(Kenkyū-buntansha) |
REID R.J. UNIV.ADELAIDE DEPT.BOTANY,RESERCH FELLOW, Reserch Fe
SMITH F.A. UNIV.ADELAIDE DEPT.BOTANY,PROFESSOR, Professor
DIETZ K.-J. UNIVERSITAT WURZBURG LEHRSTUHL BOTANIKI,SENIOR LECTURE, Senior Lec
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| Project Period (FY) |
1997 – 1998
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| Keywords | Cell membrane / Tonoplast / Characeae / Inorganic phosphate / Barley / H^+-ATPase / Inorganic ion / Plant nutrition |
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| Research Abstract |
In inorganic ion metabolisms in plant cells, vacuole is one of the most important organelles. The vacuole is usually working as ion reservoir and buffer f or the cytoplasmic ion homeostasis. For these functions, the tonoplast ion transport systems are playing important roles. In the present project, we tried to totally analyze the role of the vacuole in inorganic ion metabolisms in plant cells by means of physiology to molecular biology.
Last year, we have measured Pi uptake of isolated barley mesophyll vacuoles. Unfortunately, Pi uptake activity of barley vacuole is not high. Thus, we have tried to measure the Pi uptake activity of suspension cultured cells of Catharanthus roseus. These cells are known to have high activities of Pi uptake in both the plasma membrane and the tonoplast. As well as barley, Catharanthus vacuoles showed both ATP and PPi dependent Pi uptake. Pi uptake lineally increased until 20 mM extravacuolar Pi. Bafilomycin ; a specific inhibitor of the tonoplast H^+-ATPase also inhibited Pi uptake across the tonoplast. All these data suggested that Pi might be transported across the tonoplast driven by the membrane potential. Since the tonoplast H^+-ATPase is an important factor, we further analyzed the redox control of the tonoplast H^+-ATPase.
We are also measuring the relationship between Pi transport network across the plasma membrane and the tonoplst using isolated Chara internodal cells.
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