高锰胁迫与低pH对黄瓜根系氧化胁迫和抗氧化酶的复合效应

Combined Effects of High Level of Mn and Low pH on Oxidative Stress and Antioxidant Enzymes in Cucumber Roots

以黄瓜为材料,研究了pH6.5和pH4.5条件下高锰胁迫对根系氧化胁迫和抗氧化酶活性的影响。结果表明,随着锰浓度的提高,黄瓜根系膜脂过氧化产物MDA的含量呈明显的上升趋势,降低pH进一步加剧了膜脂过氧化程度,导致黄瓜的根系和地上部生长均受到明显抑制。高锰胁迫下Mn-SOD和Fe-SOD活性增加,在清除O2-·方面发挥重要作用。CAT对高锰胁迫比较敏感,高锰和低pH处理导致其活性明显下降,而GPX以及抗坏血酸-谷胱甘肽循环过程中的重要酶类APX、DHAR和GR在低pH和一定范围的高锰处理下活性上升,对降低高锰胁迫下活性氧伤害具有重要作用。

Effects of high level of Mn on oxidative stress and antioxidant enzymes in cucumber roots under different pH (pH 4.5 and pH 6.5) were studied. The results indicated that lipid peroxidation increased seriously with the increasing concentration of Mn, especially under low pH. As a results, the growth of cucumber roots and shoots was significantly inhibited. High level of Mn led to an elevation in activities of Mn-SOD and Fe-SOD, which played an important role in removing O2?· CAT was sensitive to high level of Mn, and its activity significantly decreased under high level of Mn and lower pH,while the activities of GPX, APX, DHAR and GR increased under low pH and some extents of high level of Mn, which indicate their important role in scavenging reactive oxygen in cucumber roots tolerance to low pH and high level of Mn.