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． Under water stress, the leaf water potential (ψL) and leaf relative water content (RWC) of loquat (Jiefangzhong and Changhong No.3) decreased, which led to the increase of O-2 production rate and the initiation of membrane lipid peroxidation, leading to cell injury. Under water stress, the activity of SOD and POD in loquat leaves increased, while CAT activity and contents of GSH and AsA were significantly different among cultivars. The activities of CAT under moderate stress and severe stress were significantly lower than those under CK while those under CK were kept at a higher level than those under CK. Under water stress, the contents of GSH and AsA in leaves were significantly decreased, On the other hand, Changhong No.3 increased significantly under mild and moderate stress. GSH content was significantly reduced under severe stress, while AsA content was still slightly higher than that of the control.