Effect of Heavy Metals on Wheat Seedlings: Activation of Antioxidant Enzymes

Accumulation of heavy metals in wheat grain exposed to multicomponent pollutants (industrial wastewater) was studied. The absolute content of metals (Zn, Cd, Cu, Cr, Ni, Co, Pb, and Mn) was found to be determined by the extent of purification of wastewater. An increase in the degree of grain contamination with heavy metals was accompanied by activation of antioxidant enzymes (superoxide dismutase, EC 1.15.1.1; catalase, EC 1.11.1.6; and peroxidase, EC 1.11.1.7) in leaves and activation of superoxide dismutase and peroxidase in roots. The ratio of activity of membrane enzymes to activity of cytosol enzymes was demonstrated to be high. It was concluded that the membranotropic effect of multicomponent contaminants was due to accumulation of heavy metals capable of inducing the antioxidant protection in the next generation of wheat seedlings.