Abstract: Superoxide dismutase (SOD) activity, malondialdehyde (MDA) accumulation and chlorophyll content, as well as the contents of abscisic acid (ABA), zeatin riboside (ZR), gibberellin (GA_1/3 ) and auxin (IAA) in the leaves were studied by using hybrid rice Tiyou 418 and its parents Tijin and C418. Different rates of leaf senescence were observed in all three rice materials. Senescence occurred the earliest and fastest in Tijin, followed by Tiyou 418 and C418. In the three rice materials, a similar trend was recorded in ABA, ZR, and IAA contents during the grain filling stage, and in (GA_1/3 +ZR+IAA)/ABA ratio. The ratio was quite stable during the early stage of leaf senescence, and decreased markedly during the late stage. The ratio declined more dramatically in Tijin, in accordance with its faster leaf senescence. The results suggested that the ratio of (GA_1/3 +ZR+IAA)/ABA regulated chlorophyll content, SOD activity, MDA content and membrane lipid superoxidation, and endogenous hormones might play a role in regulation of leaf senescence in systematically way.

Key words: rice, endogenous hormone, leaf, senescence, interaction

摘要： 以杂交水稻屉优418及其亲本屉锦和C418为材料，研究了生育后期叶片内源激素含量变化与衰老之间的关系。结果表明杂交水稻及其亲本剑叶中ABA、GA1/3、ZR和IAA含量变化趋势基本一致。3个材料的（GA1/3+ZR+IAA）/ABA的比值变化总的趋势也基本相同，前期较平稳，后期比值迅速下降。在生育后期,屉优418和C418的（GA1/3+ZR+IAA）/ABA比值下降速率较慢，与衰老相对较慢一致；而屉锦的（GA1/3+ZR+IAA）/ABA比值下降速率较快，与其衰老较快相一致。

关键词: 水稻, 内源激素, 叶片, 衰老, 相互关系