Biphasic effect of copper on growth, proline, lipid peroxidation and antioxidant enzyme activities of wheat (Triticum aestivum cv. Hasaawi) at early growing stage

The biphasic effects of Cu on the growth and some biochemical parameters of Hassawi wheat were studied. Hassawi wheat seeds were grown in various copper (Cu) levels (0, 2, 10, 20, 40, 80 and 100 mM) for 30 days. Cu was applied on soil as Cu2SO4.5H2O. The results showed that Cu concentration at 2 mM level promotes the growth and tested biochemical parameters of Hassawi wheat plants and can be considered as optimal dose. However, the studied parameters did not significantly change when Cu applied more than the above mentioned concentration up to 10 mM, and thereafter the growth and biochemical parameters were significantly reduced, compared to untreated control plants. Furthermore, the activities of antioxidant enzymes such as, catalase, peroxidase, ascorbate peroxidase and superoxide dismutase were also increased. The results support the biphasic effect of copper on Hassawi wheat growth. The stimulatory effect of Cu on the biosynthesis of free amino acids, proline and antioxidant enzyme activities could serve as important components of antioxidative defense mechanism against Cu toxicity.