Status of photosynthetic pigments, lipid peroxidation and anti-oxidative enzymes in Vigna mungo in presence of arsenic

The response to arsenic was evaluated for photosynthetic pigments, lipid peroxidation and anti-oxidative enzymes in black gram. Black gram (Vigna mungo) subjected to arsenic doses of 100 mu M and 200 mu M, showed increased amount of lipid peroxidation. Activity of peroxidase (POD) increased tremendously in arsenic treated Vigna leaves over control. Similarly, activities of enzymes like superoxide dismutase (SOD) and ascorbate peroxidase (APX) also increased with increase in arsenic. Analysis of native PAGE superoxide dismutase activity showed one manganese (Mn)-SOD and two copper/zinc (Cu/Zn)-SOD isoenzymes in black gram leaves, whose intensity increased especially at 200 mu M arsenic treatment. However, activity of catalase (CAT) decreased with increase in concentrations of arsenic. This clearly indicates that except CAT, all studied antioxidative enzymes like SOD, POD and APX showed increased expression at arsenic treatments, which reflects their protective role against arsenic toxicity in black gram plants. Photosynthetic pigments like chlorophyll and carotenoids showed reduction with increasing concentrations of arsenic in treatment solutions.