Hydrogen peroxide modulates antioxidant system and nutrient relation in maize (Zea mays L.) under water-deficit conditions

A pot experiment was conducted to investigate the effect of presowing seed treatment with H2O2 (20, 40, 60, 80, 100, 120, and 140mM) in maize grown under water-deficit conditions (moisture maintained at 100% and 60% field capacity). Higher germination rates were recorded when seeds were soaked in 140mM of H2O2. A marked decline in photosynthetic pigments and increase in the concentration of proteins, H2O2, malondialdehyde (MDA), and ascorbic acid (AsA) were recorded in maize plants under water-deficit conditions. Drought stress caused a decline in potassium (K+) and calcium (Ca2+) contents while an increase in iron (Fe2+) and phosphorous (P) contents was recorded in maize plants. Activities of different antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) were also greatly enhanced in response to water-limited supply. Among different concentrations of H2O2 (20, 40, 60, 80, 100, 120, and 140mM), seed treatment with 140mM of H2O2 greatly reduced degradation of photosynthetic pigments, decreased MDA levels, and increased the concentration of AsA and activities of different antioxidant enzymes under water-deficit conditions. Hydrogen peroxide treatment stimulated the antioxidant system that resulted in the induction of drought tolerance of maize plants in terms of higher shoot and root fresh and dry masses.