杂交水稻叶片的若干生理指标与根系伤流强度关系

本试验选用早衰程度不同的水稻品种汕优63、献改优63、亚优2号和盐粳2号。研究水稻抽穗后根系活力变化及功能叶衰老过程中的生理生化变化。结果表明:抽穗后各品种剑叶光合速率变化存在一定的差异,盐粳2号剑叶光合强度先升高,到抽穗后第7天才开始缓慢下降,而其余的品种抽穗后剑叶光合强度就开始下降,但下降的幅度和速率以献改优63号最大,亚优2号次之,汕优63最小;剑叶叶绿素含量和叶绿素a/b的值也表示相似的趋势。分析抽穗后剑叶过氧化物酶活性变化趋势发现,盐梗2号剑叶过氧化物酶活性表现出持续下降的趋势,而其余3个品种酶活性先升高,而后以不同的速率下降,而品种间剑叶过氧化氢酶和超氧化物歧化酶活性则正好相反。对抽穗后各品种根系伤流强度测定结果表明在抽穗后各品种根系伤流强度都表现出不断下降的趋势,下降幅度以献改优63最大。亚优2号和汕优63次之,盐梗2号最小。根据以上结果,作者认为:叶片衰老与根系活性密切相关,但根系的作用尚不能完全解释叶片衰老的原因。因此,阐明叶片衰老的机理尚有待进一步研究。本文还就根系对叶片衰老可能的调节机理和伤流强度作为根系指标的可靠性进行了讨论。

STUDIES ON THE RELATIONSHIP BETWEEN SEVERAL PHYSIOLOGICAL CHARACTERISTICS OF LEAF AND BLEEDING RATE OF ROOTS IN HYBRID RICE (O. SATIVA, L)

The change of root vigor and physiological and biochemical changes in flag lear after heading in rice were studied, with the varieties of Shan You No. 63, Xian Gai You No. 63, Ya You No. 2 and Yah Jin No. 2. The results indicated that there were some differences in photosynthetic rate of flag leaf after heading among different rice varieties, the photosynthetic rate of flag leaf of Yan Jin No.2 increased first, and then slightly declined after the 7th day of heading. Those of the other varietics dccrcased after heading, but the decreased range of Xian Gai You No. 63 was larger than that of Ya You No. 2, and that of Shan You No. 63 was smallest. The chlorophll content and Chla/b ratio of flag leaf showed the same changes. The pcroxidasc activity of flag leaf of Yan Jin No. 2 constantly declined after heading, and those of other varieties increased first, and then declined differently. The changes of eatalase and SOD activities among varieties turned out contrary to the rcsults above. The bleeding rates of root of various rice varieties dccrcased after heading, but the dccrcased range, from large to small, was Xian Gai You No. 63, Ya You No. 2, Shan You No. 63 and Yan Jin No.2. It was suggested that there was close relationship between leaf sencscence and root activity, but the cause of leaf seneseence did not completely result from the decrease of root activity.