The supplementation of Cu- contaminated nutrient solution with 40- 400 mg L-1 of soybean (Glycine max L.) seedlings with 5 mM CaCl2 was studied. Excess Cu2+ caused a significant decrease of growth parameters, photosynthetic pigments (Chl.a, Chl.b, and carotenoids), and Ca2+ concentration in shoots and roots, while enhanced the Cu2+ accumulation. Furthermore, Cu2+ increased the production of ROS, lipid peroxidation as indicated by increase of malondialdhyde (MDA) content, as well as antioxidant enzyme superoxide dismutase and peroxidase (SOD, POD) activities. Excess Cu2+ depressed catalase (CAT) activity in soybean plants. Application of Ca2+ alleviated the inhibitory effect of Cu2+ on growth and oxidative damages as evidenced by lowering hydrogen peroxide (H2O2) and (MDA) contents. Moreover addition of Ca2+ resulted in a significant increase of CAT and POD activities in Cu-stressed soybean seedlings. The results of this study indicated that Ca2+ shift to some extent, the toxic effects of Cu2+ on soybean growth.
Key words: Soybean, Superoxide dismutase, Ccatalase, peroxidase, Malondialdhyde copper, Calcium, Hydrogen peroxide
|
