不同浓度Hg2+ 、Cr3+ 和Pb2+单一胁迫对绿豆膜脂过氧化物含量及抗氧化酶活性的影响

研究了不同浓度Hg2+、Cr3+ 和Pb2+胁迫条件下，绿豆花荚期叶片中膜脂过氧化物（MDA）含量及抗氧化酶，包括(超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT))活性的变化情况。结果表明，Hg2+、Cr3+和Pb2+胁迫后，随着浓度的升高，绿豆叶片中MDA含量也逐渐升高，与对照相比均呈差异显著性；在Cr3+和Pb2+胁迫下，绿豆叶片中SOD酶活性随着浓度的升高呈现升高的趋势；在低、中浓度Hg2+胁迫下，SOD酶活性低于对照，但高浓度下，SOD酶活性高于对照；Hg2+处理后，POD随着浓度的增加，表现出先升高后降低又升高的趋势；低、中浓度Cr 3+处理使绿豆叶片内POD活性降低，但在高浓度时表现出POD活性增强；随着Pb2+处理浓度的增加，POD活性逐渐降低；Hg2+ 和Cr3+处理使CAT活性升高，但Pb2+处理后，CAT活性随浓度的升高先下降，再升高，然后又下降。研究表明Pb2+对绿豆的生态毒性较大。

Effects of Hg2+,Cr3+ and Pb2+ Stress on the Membrane Peroxidation Content and Activities of Antioxidant Enzymes

The effects of different concentration of Hg~(2+),Cr~(3+) and Pb~(2+) on the membrane peroxidation(MDA)content and antioxidant enzymes activities(supemxide SOD,POD,CAT)in mung bean in podding period were studied.The results showed that,under the stress,MDA content in mung bean leaves increased gradually,with the increase of treating concentration,it shown a significant difference compared with control.The activity of SOD increased as the concentration increased under the stress of Cr~(3+) and Pb~(2+).The activity of SOD was lower than control under low concentration(10 mg/kg-soil)and moderate concentration(50 mg/kg-soil)of Hg~(2+),but it was higher than control with high concentration of Hg~(2+)(100 mg/kg-soil).With the increase of concentration under the stress of Hg~(2+),POD activity Was first increased,then decreased and increased again.POD activity decreased under the stress of low concentration(5 mg/kg-soil)and moderate concentration of Cr~(3+)(20 mg/kg-soil),but it increased under high concentration of Cr~(3+)(50 mg/kg-soil).As the increase of Pb~(2+) concentration,POD activity decreased gradually.CAT activity increased under treatment of Hg~(2+) and Cr~(3+),but with the increase of concentration,CAT activity was in the partten of decrease-increase-decrease under Pb~2+stress(the Pb~(2+) concentration of 50,200 and 600 mg/kg-soil).This investigation indicated that Pb~(2+) had a seriously ecotoxicological effect in mung bean.