Antioxidant Responses of Pea Genotypes to Zinc Deficiency

The effects of Zn deficiency on antioxidant responses of two pea (Pisum sativum L.) genotypes, a Zn-efficient IPFD-99-13 and Zn-inefficient KPMR-500, grown in sand culture were studied. In the pea genotype KPMR-500, Zn deficiency decreased dry matter yield, tissue Zn concentration, and antioxidant enzyme activities istronger than in the genotype IPFD-99-13. Genotype IPFD-99-13 developed more efficient antioxidant system to scavenge ROS than genotype KPMR-500. Zinc deficiency produced oxidative damage to pea genotypes due to enhanced accumulation of TBARS and H2O2 and decreased activities of antioxidant enzymes (Cu/Zn superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX)). In the leaves of IPFD-99-13 genotype, the higher activity of ROS-scavenging enzyme, e. g., SOD, CAT, POD, and glutathione reductase, and antioxidants, such as ascorbate and non-protein thiols, led to the lower accumulation of H2O2 and lipid peroxides. These results suggest that, by maintaining an efficient antioxidant defense system, the IPFD-99-13 genotype shows a lower sensivity to Zn deficiency than the KPMR-500 genotype.