Lanthanum- and cerium-induced oxidative stress in submerged Hydrilla verticillata plants

Oxidative stress was induced in 10-day treated with lanthanum and cerium Hydrilla verticillata plants. Low 10 mu M concentrations did not exert harmful effects. The plants treated with higher concentrations showed higher H2O2 content and lower chlorophyll and soluble protein contents as compared to control plants. At the same time, malondialdehyde content rose with increasing concentrations of La and Ce. As La and Ce concentrations increased, superoxide dismutase and catalase activities declined progressively, while peroxidase activity increased. Proline content decreased slightly at 10 mu M La or Ce and then rose with higher concentrations. The results indicated that La and Ce caused oxidative damage as evidenced by increased lipid peroxidation and decreased chlorophyll and protein levels.