以 3个不同耐旱性的菜苔 (Brassica parachinensis L .H .Bailey)品种为试材 ,研究了干旱胁迫对叶片保护酶活性和膜脂过氧化的影响及其与抗旱性的关系。干旱胁迫条件下 ,菜苔叶片的电解质外渗率和MDA含量呈上升趋势 ,叶绿素含量、抗坏血酸含量和SOD活性呈下降趋势 ,CAT活性表现为先上升后下降。耐旱品种比不耐旱品种具有较高的叶绿素含量和抗坏血酸含量 ,具有较低的电解质外渗率和MDA含量 ;耐旱品种的SOD活性比不耐旱品种下降幅度小。轻度干旱胁迫下 ,耐旱品种的CAT活性上升幅度比不耐旱品种高 ;重度干旱胁迫下耐旱品种的CAT活性下降程度比不耐旱品种低。耐旱品种的POD活性在干旱条件下先上升而后降低 ,不耐旱品种的POD活性处于下降趋势。干旱 6d后 ,耐旱品种的SOD、CAT和POD活性显著高于不耐旱品种。

The effects of drought stress on the membrane lipid peroxidation and protective enzymes activities in leaves of Brassica parachinensis L. H. Bailey were studied with three different drought tolerant cultivars. The results showed that much higher contents of chlorophyll and ascorbic acid, much lower the rate of electrolyte leakage and malondialdephyde ( MDA) content, the declining degree of superoxide dismutase ( SOD) activity were appeared in drought-tolerant cultivars than those in drought-sensitive cultivar under drought stress. The ascending range of catalase ( CAT) activity in drought-tolerant cultivars was higher than that in drought sensitive one under slight drought stress, and the declining degree of CAT in former was lower than that in the latter under severe drought condition. The peroxidase ( POD) activity of drought-sensitive cultivar decreased gradually, but that of drought-tolerant cultivars increased at first, then decreased in drought stress.