Abstract
This study was conducted to evaluate the effect of different concentrations of cadmium (Cd) (0, 100, 200, and 400 mu M Cd) on two genotypes (AG-10 and AP-3) of Pisum sativum. Cd stress reduced the length, fresh weight, and dry weight of roots and shoots in both genotypes. Chlorophyll 'a' and `b' and carotenoid content was also decreased and greater decreases were observed for higher concentrations of Cd. As Cd stress increased, levels of proline, glycine betaine, and soluble proteins were increased and sugar content was decreased. The application of Cd also caused an increase in hydrogen peroxide, lipid peroxidation, and electrolyte leakage in both genotypes. The activities of defensive antioxidant enzymes like superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase, and glutathione S-transferase were also increased with increasing Cd concentrations; however, the increase in AG-10 was greater than in AP-3. The accumulation of phenols was decreased with Cd stress in both pea genotypes, with the greatest decreases were observed in AP-3. In conclusion, Cd caused a marked reduction in growth, biomass yield, and pigment content in both pea genotypes. However, enhanced accumulation of osmolytes and antioxidant enzyme activities alleviated the adverse effects of Cd. AG-10 was more tolerant genotype than AP-3, as AG-10 showed less Cd induced damage and higher antioxidant enzyme activities.