Effects of phosphorus on antioxidant system in pepper cultivars under saline conditions.

Salinity is one of the most severe abiotic stresses in one-half of all irrigated lands, causing negative effects on physiological, biochemical, and molecular responses in plants. Application of chemical fertilizers, particularly phosphorus (P) fertilizers, may reduce harmful effects of salinity. In this study, an investigation was performed on the effects of exogenous application of different levels of phosphorous (0, 40, and 80 mg/kg soil as CaHPO4) on hydrogen peroxide (H2O2) and malondialdehyde (MDA) generation, the content of soluble proteins, and activities of antioxidant enzymes like superoxide dismutase (SOD) and peroxidase (POD), in shoots of two different cultivars of Capsicum annuum L. (cv DS 77-172 and cv Sera) under different concentrations of NaCl (0, 50, and 150 mM). Treatment of salt stressed grown seedling with CaHPO4 increased activity of POD. Under salinity conditions, phosphorous treatment decreased contents of H2O2 and MDA. These results indicate salt-induced deleterious effects in both pepper cultivars alleviated by phosphorous treatment.