Hydrogen Peroxide Ameliorates the Adversities of Drought Stress during Germination and Seedling Growth in Sorghum (Sorghum bicolor L.)

Proper seed germination is important for seedling establishment and growth in fields under drought caused by climate change. In the present study, the beneficial effects of hydrogen peroxide on seed germination were investigated by proteome analysis. Sorghum seeds were subjected to drought stress adjusted to the various water potentials of 0, −0.2, and −0.5 MPa using polyethylene glycol (PEG) 6000 and treated with hydrogen peroxide at different concentrations (0, 10, 20, 50, and 100 mM). Germination percentage and seedling growth were determined at 6 days after imbibition, and proteins from embryos were analyzed. As a result of the study, it was found that the reduced germination percentage and seedling growth under drought stress were alleviated by hydrogen peroxide treatment. Proteins induced in hydrogen peroxide-treated embryos included glycolysis-related enzymes (25%) and stress-defense proteins (30%). Among the glycolysis-related enzymes, fructokinase-1 was higher only under drought and 0 mM H2O2 treatment, and phosphoglycerate kinase was higher than control under drought and 100 mM H2O2 treatment. Hydrogen peroxide treatment also increased the expression of antioxidant enzymes related to stress defense. The results that hydrogen peroxide treatment increases germination rate and seedling growth by increasing energy production and defense activity suggest a practical application of H2O2 at 100 mM for reducing the drought stress in sorghum.