水稻叶片的衰老与超氧物歧化酶活性及脂质过氧化作用的关系

研究了从抽穗开花到籽粒成熟过程中,水稻植株顶部三片叶子的超氧物歧化酶(SOD),脂质过氧化产物丙二醛(MDA)含量及二磷酸核酮糖羧化酶活性的变化。实验结果表明:叶片的衰老伴随着 SOD 活性、RuBP 羧化酶活性及叶绿素含量的降低、丙二醛含量显著增高。分离了三个 SOD 的同工酶,证明为 Cu—Zn SOD。观察了 SOD 同工酶在叶片老化及酶液存放不同时间中的变化。讨论了叶片衰老过程中氧自由基对酶及质膜的损伤影响。

SUPEROXIDE DISMUTASE ACTIVITY AND LIPID PEROXIDATION IN RELATION TO SENESCENCE OF RICE LEAVES

Superoxide dismutase(SOD),lipid peroxidation,ribulose 1,5-bisphosphate carboxylase and chlorophyll content in the leaves of rice were investigated during bloom- ing to ripening stages.The results indicated that leaf senescence was associated with the decreases of SOD and RuBP carboxylase activities and chlorophyll content.A marked increase of malondialdehyde(MDA)content,a product of lipid peroxidation was observed during leaf senescence.However,the relative high activities of SOD and RuBP carboxylase and chlorophyll content,lower MDA content in hybrid rice senes- cence leaves,compared with their three lines,suggest the presence of physiological hy- brid vigor.The analysis of polyacrylamide gel electrophoresis showed that three SOD isozymes in leaf extract,which were Cu-Zn SOD.Changes of SOD isozymes were observ- ed during leaf agling and at different time of storage of its extract.The destroying effect of oxygen free radical on enzymes and membrane in the course of leaf senescence was discussed.