水分胁迫对枇杷叶片活性氧代谢的影响

水分胁迫使枇杷（解放钟及长红3号品种）叶片水势（ψL）和叶片相对含水量（RWC）下降，引起叶片O－2产生速率增大，启动膜脂过氧化，从而导致细胞伤害．水分胁迫下，枇杷叶片SOD、POD活性均增加，而CAT活性和GSH、AsA含量则品种间差异明显．解放钟CAT轻度胁迫时活性增加，中度及严重胁迫下活性比对照显著降低，而长红3号则保持比对照高的水平；水分胁迫下，解放钟叶片GSH、AsA含量均明显降低，而长红3号则在轻度及中度胁迫下明显增加，严重胁迫时GSH含量显著降低，AsA含量仍比对照略高．

Effects of water stress on activated oxygen metabolism in loquat leaves

Grafted seedlings of two lequat varieties (Jiefangzhong and Changhong No. 3 ) were used in this study. Under water stress, the relative water content (RWC) and water potential (ψL) in leaves decreased. the generation rate of O, lipid peroxidation and the contents of malondialdehyde (MDA) increased, so cells were damaged. Meanwhile, the activities of superoxide dismutase (SOD) and peroxidase (POD) increased; the activities of catalase (CAT), the contents of reduced glutathione (GSH) and ascrobate (AsA) different between two varieties. The activities of CAT in Jiefangzhong's leaves increased under light water stress, but decreased markedly than those in the control under moderate or severe water stress, while those in Changhong No. 3 kept much higher level than those in the control under water stress. The contents of GSH and AsA in Jiefangzhong's leaves decreased markedly under water stress, but those in Changhong No. 3's increased much under light or moderate water stress. Under severe water stress, the contents of GSH in Changhong No. 3's decreased, but the contents of AsA were still higher than those in the control.