Molecular Physiological and Ecological studies on the Plant Hormonal Regulation in Rice Production.

本文研究了植物激素的生理生态作用方式及其对水稻营养生长和生殖生长，特别是灌浆过程的调控作用。我们还以大豆植株为实验材料。这些植物不仅在日本，而且在世界上都是重要的主食植物。1.在水稻的生活史中，第2叶期的第2叶在光照条件下产生大量乙烯，而第3叶期的第3叶在光照条件下产生大量乙烯，第2叶在乙烯产生方面表现出不同于其它叶的特殊性，其糖（淀粉和蔗糖）含量高。各叶期的大部分叶鞘、开花和成熟生长期的柱子以及成熟的穗也对乙烯产生有光（8，000 lux左右）的促进作用。这是我们的新发现之一。在光照条件下，水稻雄性不育系和雌性不育突变体开花后的空穗乙烯释放量均低于正常穗。结果表明，成熟期（尤其是乳熟期）水稻穗中糖的积累与乙烯的显著释放密切相关.因此，在决定穗轴数和粒数时，应在幼穗分化期，即营养生长向生殖生长的过渡期，保持适宜的内源赤霉素浓度。促熟素是一种新的植物激素，它能提高水稻的成熟率，促进水稻低温后熟。内源脱落酸含量与大豆成熟度也有密切关系。

We studied on the physiological and ecological mode of action of plant hormones and their regulatory action in plant growth and development of rice life cycle including vegetative and reproductive growth, especially grain filling. We also used soybean plant as the experimental materials. These are important staple food plants not only in Japan, but also in the world.1. In rice life cycle, 2nd leaf blade in 2nd leaf stage greatly produced ethylene under light condition deferent from 3rd leaf in 3rd leaf stage including other leaf stage, 2nd leaf expressed special character different from other leaf in ethylene production with big amount of sugar contents (Starch and sucrose). Most leaf sheath in various leaf stage, colum in flowering and ripening growth stage, and maturing panicle also had light (round 8,000 lux) promotion effects for ethylene production. This was one of our new finding results.2. Empty panicle after flowering in male sterile and female sterile mutants rice lines had not so much ethylene production deferent from normal panicles under the light condition. We found that it was closed relation ship between the sugars accumulation and the remarkable ethylene production in matured rice panicles (especially in milk-ripe growth stage).3. It was strongly indicated that the appropriate concentrations of endogenous gibberellin should be present in whole plant at panicle initiation stage at the transit stage from vegetative to reproductive for determination of rachis and grain numbers. Brassinolide, one of new plant hormones, activated percent of maturation grain rate and the ripening under low temperature condition in rice. Endogenous abscisic acid content had also closed relationship with soybean maturation.