Effect of Gibberellin on Spikelet Organogenesis in Rice Plants under Different Treatment of Nitrogen Top-dressing
[摘要] The effect of nitrogen top-dressing (ntd) on the gibberellin (GA3, GA) - induced abnormality of spikelets was investigated during the two years, 1986 and 1987, with using the rice cultivar Sachikaze. Plants grown in 1/5, 000 a pots filled with paddy soil were top-dressed with different amounts of nitrogen at the maximum tillering stage, and one week after, the plants were treated with GA of 500 ppm until the final concentration was reduced to 50 ppm. Three levels of ntd with or without GA treatment were tested in six experimental plots; (1) No ntd (0 N), (2) Standard ntd (1 N), which was applied with 0.5 g of ammonium sulfate, (3) Three-times amont of ntd (3 N), which was applied with 1.5 g of ammonium sulfate, (4) GA application and 0 N (0 N+GA), (5) GA application and l N (1 N+GA), and (6) GA application and 3 N (3 N+GA). Plant height, and numbers of secondary branch and spikelet increased in all plots of ntd especially in those with GA apply. The percentage of spikelets with any abnormal organs in GA treated plants increased with ntd. A decrease in number of stamens to five or less, and pistil with three stigmas were prominent abnormalities observed in the study. Third stigma development was observed in 3 N plot even without GA application, showing highest 30% with GA application. The distribution pattern of abnormal organs in the panicle was similar in both additional glume and stamen, however, it was different in the pistil. Under high ntd level, GA application induced both suppression of stamen development and promotion of pistil differentiation under high frequency; GA supplied without ntd brought on increase in stamen development. These results indicate that the effect of GA in morphogensis of reproductive organs in rice changes with ntd conditions. GA was found to promote the effect of nitrogen in increasing female organogenesis, similar in effect to that of auxin applied exogenously.
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[效力级别] [学科分类] 农业科学(综合)
[关键词] Gibberellin;イãƒ;Nitrogen top-dressing;器官形æˆ;Organogenesis;雌性化;Pistillody;å°ç©‚;Rice;ジベレリン;Spikelet;çª’ç´ è¿½è‚¥;Young-panicle differentiation;幼穂始原体分化 [时效性]