盐胁迫对大果沙枣膜脂过氧化和保护酶活性的影响

Effects of Salt Stress on Membrane Lipid Peroxidation and Protective Enzymes in Leaves of Elaeagnus angustifolia L.

用50,100,200,300 mmol/L NaCl处理大果沙枣,NaCl胁迫10,20,30 d后取叶样测定结果显示:处理10 d的大果沙枣叶片细胞膜透性保持稳定,随盐浓度的增加及胁迫时间的延长,叶片细胞膜透性逐渐增加。NaCl胁迫30d时,300 mmol/L NaCl胁迫的叶片膜透性达到68.8%。整个处理过程中,丙二醛含量逐渐增加,但增加幅度不大,表明脂质过氧化反应水平较低。各处理浓度的SOD和POD活性整体上呈增加趋势,其中NaCl胁迫10 d和30 d,胁迫浓度50 mmol/L时其活性达到最大值。另外,SOD和POD活性随着时间的延长有所降低,CAT活性则一直增加。

Elaeagnus moorcroftii was treated by NaCl stress with concentrations of 50, 100, 200 and 300 mmol/L, and the membrane liquid peroxidation and endogenous protective enzymes in leaves of Elaeagnus moorcroftii were studied after 10, 20 and 30 days. The results show that the membrane permeability kept stable after Elaeagnus moorcroftii was treated by NaCl stress for 10 days, and the membrane permeability under NaCl stress with concentration of 300 mmol/L was only 24.6%, which reveal that the leaves of Elaeagnus moorcroftii were not injured. However, the membrane permeability in leaves of Elaeagnus moorcroftii was gradually increased with the increase of the NaCl stress time and concentration, and it was increased to 68.8% after Elaeagnus moorcroftii was treated by NaCl stress with concentration of 300 mmol/L for 30 days; when NaCl stress was continued for 30 days, the membrane permeability in leaves of Elaeagnus moorcroftii was slowly increased under NaCl stress with low concentration, but it was rapidly increased under NaCI stress with high concentration, and the cellular membranes of the leaves of Elaeagnus moorcroftii were injured to a certain extent. The malondialdehyde content was increased while treating, but its increase was not so significant, which reveals that the level of membrane liquid peroxidation was low. SOD and POD activities in leaves of Elaeagnus moorcroftii under NaCl stress with the different concentrations were generally increased, and they reached to their maximum values when Elaeagnus rnoorcroftii was treated by NaCl stress with concentration of 50 mmol/ L for 10 and 30 days. SOD and POD activities were reduced to some extent with the time, but CAT activity was increased all along.