1988 Fiscal Year Final Research Report Summary
Studies on the regulatory mechanisms of growth of cultured plant cells and organelles
| Project/Area Number |
61560005
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Breeding science
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| Research Institution | Kobe University |
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Principal Investigator |
NAKAMURA Chiharu Kobe University Dept. of Plant Protection, Fac. of Agriculture, Assistant, 農学部, 助手 (10144601)
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| Co-Investigator(Kenkyū-buntansha) |
ONO Hajime Kobe University Dept. of Plant Protection, Fac. of Agriculture, Professor, 農学部, 教授 (40031166)
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| Project Period (FY) |
1986 – 1988
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| Keywords | Plant tissue culture / Cell growth / Cell differentiation / Morphogenesis / Nuclei and organelles / Plant hormones / Auxin / オーキシン受容体 |
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| Research Abstract |
Our research objectives were to understand the regulatory mechanisms of cell growth, differentiation and organellar development using cultured plant cells. We analyzed nucleic acid and protein syntheses, photosynthesis and respiratory activity during growth of tobacco cells at both the cellular and organellar levels. In addition, we analyzed a membrane-bound auxin-binding protein in tobacco which was thought to mediate auxin action in cell growth and differentiation.
The results obtained are summarized as follows, i) photosynthetic activity developed in a 2,4-D-sustained photomixotrophic line of tobacco during growth in the light. The development of photosynthetic activity correlated with the synthesis of several chloroplast proteins including a small subunit of Rubisco and with the developwent of photosystem II activity; 2) heterotrophically grown tobacco cells showed growth cycle-related changes in the respiratory activity measured both at the cellular and mitochondrial levels. The ch
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anges in the respiratory activity occurred mainly through the cytochrome pathway, while the activity of the cyanide-resistant alternative pathway remained constant throughout the growth cycle. Kinds and amounts of sugars exogenously supplied did not affect the relative contribution of the alternative pathway. Our results show that the respiration is under strong control by adenylates and suggest that the alternative pathway plays a role other than an energy overflow; 3) a membrane-bound auxin-binding protein (MABP) was solubilized from cell suspension cultures of tobacco and characterized. The results show that MABP is a class of auxin-binding protein distinct from a cytosolic soluble type. Using an auxin-resistant variant and a transformant by agrobacterium tumefaciens, MABP was shown to be regulated by cytokinin and involved in auxin-mediated root differentiation. A role of MABP in root differentiation was also shown using an organ (root) culture system in which root differentiation could be manipulated. Less
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