31 植物の光屈性分子の化学及び生物学(口頭発表の部)

概要

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Most people are familiar with the sight of a young seedling bending towards a window or the brightest source of light to which it is exposed. This directional growth response is known as phototropism, which is caused by a lateral gradient of growth-promoting auxin in the bending organ (Cholodny-Went theory). In contrast to the C.-W. theory, Bruinsma and Hasegawa recently found that the shaded half did not contain more auxin than the illuminated ones. Instead it was found that the even distribution of auxin was accompanied by a lateral gradient of growth inhibitory substances during phototropic curvature. We have isolated some photo-induced growth inhibitory substances related to phototropism, raphanusanins from radish (Raphanus sativus var. hortensis f. gigantissimus Makino) hypocotyls, benzoxazolinones from light-grown maize (Zea mays L.) shoots, indolylacetonitrile from light-grown shoots (Brassica oleacea L.), and 8-epixanthatin from sunflower hypocotyl, and uridine from oat coleoptile. And chemical analyses have shown phototropic stimulations to cause curvature by inducing a local unequal distribution of growth-inhibiting substances that antagonize auxin in its cell-elongating activity. Finally, the mechanism of phototropism in plants is described in Scheme 4.
天然有機化合物討論会の論文
2000-10-01