Exogenous hydrogen peroxide up-regulates the contents of ascorbate and glutathione in the leaves of Vigna radiata (Linn.) Wilczek. exposed to salt stress

Abstract

In this paper, the effect of exogenous hydrogen peroxide (H2O2) on the contents of ascorbate and glutathione in Vigna radiata (Linn.) Wilczek. leaves exposed to salt stress was determined. The findings showed that salt stress increased the activities of ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), gamma-glutamylcysteine synthetase (γ-ECS), electrolyte leakage (EL) and the contents of reduced ascorbate (AsA), reduced glutathione (GSH), total ascorbate, total glutathione and malondialdehyde (MDA). Exogenous H2O2 increased the contents of AsA, total ascorbate, GSH and total glutathione through APX, GR, DHAR and γ-ECS in leaves exposed to salt stress. Above increases were also induced by exogenous H2O2 alone, compared with control. Exogenous H2O2 had no effect on the activities of l-galactono-1,4-lactone dehydrogenase (GalLDH) and MDHAR and total ascorbate content. Exogenous H2O2 significantly reduced MDA content and EL induced by salt stress. Above results indicated that exogenous H2O2 could enhance the salt tolerance of V. radiata by regulating the ascorbate and glutathione metabolism.