1996 Fiscal Year Final Research Report Summary
STUDIES ON THE ROLE OF VACUOLES IN ION METABOLISMS IN PLANT.
| Project/Area Number |
08044198
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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 Institution | HITOTSUBASHI UNIVERSITY |
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Principal Investigator |
MIMURA Tetsuro HITTOTSUBASHI UNIVERSITY FACULTY OF COMMERCE ASSOCIATE PROFESSOR, 商学部, 助教授 (20174120)
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| Co-Investigator(Kenkyū-buntansha) |
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) |
1996
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| Keywords | Barley / Vacuole / Tonoplast / Inorganic ion / Plant nutrition / H^+-ATPase / Characeae / Inorganic phosphate |
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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 for 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 organic ion metabolisms in plant cells by means of physiology to molecular biology.
Dr.Dietz and I (Dr.Mimura) isolated the tonoplast from barley plants which were cultured under different nutrient conditions and suspension cultured cells of mangrove plant in Japan. We have measured the ATPase and H^+-pumping activities of the tonoplast using the specific in hibitor ; Bafilomycin. We have found that the adenine nucleotides and the norganic phosphate are working as regulators of the tonoplast H^+-ATPase. We showed that the initial fluctuation of the light-induced vacuolar acidification could be explained by the changes in the tonoplast H^+ -ATPase activity proportion al to the changes in the cytoplasmic adeninenucleotide levels. Furth ermore, we noticed that the redox conditions might be also working as one of controlling factors in situ.
In Australia, Dr.Smith and I (Dr.Mimura) measured the relation ship between Pi transport across the plasma membrane and the vacuolar Pilevel usint isolated Charainternodal cells. By incubating internodal cells in media Gaving different concentrations of Pi, we first succeeded to control the Pitransport and the vacuolar Pi levelindependently. The Pi uptake activity of the plasma membrane changed independent of both the cytoplasmic and the vacuolar Pi pools. We are now trying to measure the Pi transport activity across the tonoplast in the cell.
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