8. シロイヌナズナ種子成熟過程におけるジベレリンの機能

概要

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The goal for this study is to elucidate roles of gibberellin (GA) in seed maturation of Arabidopsis. Previously we had shown; i) AtGA20ox3, a GA 20-oxidase gene were expressed in integument of the seed at 5 day-after-pollination (DAP), where starch granules were observed, ii) the starch granules disappeared at 9 DPF, and iii) the expression of Amy3, a major α -amylase gene in the seed, initiated at 7-9 DAP. These observations suggest that GAs play a role for the degradation of starch through the induction of at least α -amylase gene in integument. In this report, we show some data supporting our speculation about GA function, and the morphological effect of GA starvation in the integument. We examined the expressional site of AtGA20ox2, AtGA3ox4 and Amy3 genes, by in situ hybridization, too. They were expressed at two sites in the seed simultaneously; the integument and epidermal cells of embryo. It was also elucidated that the applied GA to silique resulted in the increase of Amy3 mRNA, showing that its expression was GA-inducible. gal-3 seeds obtained by insufficient GA sprays to plant, showed their abnormalities on the surface arrangement and in swelling after imbibition, suggesting that GA would be involved in the construction of the structure of seed surface.
2004-10-13