Abstract
Pretreatment of soybean (Glycine max (L.) Merr.) seeds with hydrogen peroxide (H2O2) promoted their growth rates at low water potentials. Seeds were pretreated with H2O2 and sowed in vermiculite medium with water potential of −0.02 MPa (as the control with adequate water in vermiculite) and −0.18 MPa (as the low amount of water in vermiculite). Among examined concentrations, 20 mM of H2O2 had the highest effects on the growth of seedlings at low water potential. Roots exhibited more elongation improvement than hypocotyls at low water potential. The osmotic adjustment was extremely promoted in seedlings with H2O2-pretreatment in seeds in 50 h after sowing. The data indicate that such extreme osmotic adjustment was associated with a large size of the growth-induced water potential in roots and hypocotyls. Furthermore, water permeability in the zone of elongation was decreased in seedlings H2O2-pretreated. At low water potential, seedlings with H2O2-pretreatment in seeds could import more solutes and water in cells in the zone of elongation while faster cell elongation went on by absorbing water from the low amount of water in vermiculite.
