Effects of Pb, Cd, and Zn on Oxidative Stress and Antioxidative Ability in Phragmites australis
铅、镉和锌污染对芦苇幼苗氧化胁迫和抗氧化能力的影响

Superoxide anion radical, MDA, electrolyte leakage, as well as activities of SOD and POD in the leaf and root cells of Phragmite australis were investigated under the conditions of Pb, Cd, and Zn stresses. Under these conditions, the accumulation of superoxide anion radical and MDA, and the electrolyte leakage of the cell membrane increased in the plant cells, which indicated that the peroxidation of cell membrane lipid was induced and the membrane system was damaged. Higher activity of SOD and POD, two key enzymes of the antioxidative system, was observed in all Pb, Cd, and Zn treated plant cells. These results suggest that the enhancement of peroxidation of membrane lipid induced by superoxide anion radical may be one of the heavy metal injury mechanisms in P. asutralis. Furthermore, the accumulation of the two enzymes would be part of general defense strategies to cope with oxidative stress.