Evaluation of lead and copper distribution in Alfalfa (Medicago sativa L.) Hamadani cultivar and the role of two antioxidant enzymes

Using plants for extracting metals have been discussed as a promising alternative in extracting extra metals from soil and water. The aim of plant extraction is therefore decrease in metal concentrations in contaminated soils for which the plant tolerance is of high importance. On this basis in order to predict and understand the ability of alfalfa in absorption and remediation of heavy metalslead and copper and the antioxidant behaviors of Superoxide dismutase and Catalase to such metals an experiment was conducted with alfalfa (Medicago sativa) cultivar Hamedani in the fall of 2009. Four levels of lead (Pb(NO3) 2) 0, 200, 400، 800 and four levels of copper (Cu(SO4) 2) levels 0, 150, 300 450 mg/kg soil were used. The experiment was carried out in factorial form as completely random design with 4 replicates. Results suggested more absorption of lead and copper in aerial parts than root system. The measured values of lead and copper transmition factor were clearly indicated more lead and copper absorption in aerial parts than root system. Copper was absorbed more in aerial parts than lead. Results for enzymes Superoxide dismutase (SOD) and Catalase (CAT) assay demonstrated with the increase in the level of lead and copper the antioxidant behaviors of the two enzymes increased significantly (P<0. 01).