Hydrogen peroxide promotes the tolerance of soybeans to waterlogging

We investigated the role of pretreatment of seeds with hydrogen peroxide (H2O2) in promoting the tolerance of seedlings of Glycine max to waterlogging. Soybean seeds were pretreated with a solution of H2O2 70 mM or water for 24 h under aeration, and then were placed in plastic bags containing substrate. At 12 days after sowing, the seedlings were subjected to waterlogging for 32 days. There were three evaluations: 0, 16 days and 32 days of waterlogging. Biomass accumulation, root volume, stem diameter, gas exchanges, activity of antioxidant system and cell membrane damages were evaluated. The pretreatment of seeds with H2O2 generated seedlings with elevated activity of antioxidant enzymes, low H2O2 and O-2(-center dot) content, and low cell membrane damages. Hydrogen peroxide pretreatment also resulted in increased content of photosynthetic pigments and net photosynthetic rate, high biomass accumulation, root volume and stem diameter. H2O2 pretreatment of soybeans seeds generated seedlings more tolerant to waterlogging. There is probably a stress memory involved in the process of induction of tolerance in soybeans mediated by hydrogen peroxide.