Effects of excess copper on the oxidative stress in roots of maize seedlings

Abstract

Though Cu is a necessary nutrient element for organism, it can cause damage to biota inhabited in Cu-contaminated regions. Zhendan958 is one of the dominant cultivar of maize (Zea mays L.) in China in the last five years due to its better traits in production. To assay the acute resistant response of Zhendan958 under Cu stress, the seedling was treated with 2 to 8 mM Cu for 96 h and many physiological parameters were assayed in the roots. Cu inhibited the bioaccumulation of root biomass but increased the accumulation of Cu in roots. Cu stress induced the loss of plasma membrane integrity and lipid peroxidation as revealed by the histochemical staining and increased malondialdehyde content. Cu stimulated the activity of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, glutathione reductase and glutathione S-transferase. Cu stress altered the content of glutathione, ascorbic acid significantly. These indicated seedlings of Zhendan958 can grow in median level of Cu contaminated soils for aims to phytoremediation. Key words: Maize, superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, glutathione reductase, glutathione S-transferase.