盐胁迫对沙枣幼苗抗氧化酶活性和膜脂过氧化的影响

采用NaCl模拟盐胁迫处理沙枣幼苗，测定了超氧化物岐化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）活性和丙二醛（MDA）含量的变化。结果表明：在盐胁迫下，沙枣幼苗的SOD活性呈现出降-升-降的趋势，在NaCl浓度为2．0％时，出现活性高峰；随着盐浓度的增加，SOD活性下降：当NaCl浓度达到4．0％时，其活性低于对照。POD活性呈现出先上升后下降的趋势，NaCl浓度为2．0％时，POD活性达到最大值。CAT活性的变化趋势与POD相似。随着NaCl浓度的增加，MAD的含量开始下降；当盐浓度为0．4％时，MDA含量最低：随后，MDA含量上升。这说明，在一定程度的盐胁迫下，沙枣幼苗通过提高抗氧化酶活性和降低膜脂过氧化来减轻活性氧对植物细胞的损伤。

Effects of Salt Stress on Activities of Antioxidant Enzymes and Membrane Lipid Peroxidation of Elaeagnus angustifolia L. Seedlings

Elaeagnus angustifolia L. seedlings were treated by the salt stress using NaCl solution. The activities of SOD, POD, CAT and the content of MDA were analyzed. The results show that the activity of SOD presented the tendency of first decreasing, then increasing and decreasing again. The peak of the SOD activity emerged when treated with 2.0% NaCl. Along with the concentration increase, the SOD activity decreased, and was lower than that of the control at the 4.0% NaCl concentration. The activity of POD presented the tendency of first increasing and then decreasing, and the peak of the activity emerged when treated with 2.0% NaCl. The tendency of CAT activity was similar to that of POD. The content of MDA decreased at the beginning of the salt stress, and it was the lowest when treated with 0.4% NaCl. After that, the MDA content increased. The results indicate that the injuries of active oxygen were alleviated through increasing the activity of antioxidant enzymes and decreasing the membrane lipid peroxidation in the seedlings of E.angustifolia L. under certain salt stress.