Effect of salinity on some enzymatic and non-enzymatic antioxidants of Asada-Halliwell pathway in P. cineraria and P. juliflora

Abstract Increased level of antioxidants and enzymatic activity protects the plants from oxidative damage under stress conditions. In the present study antioxidants involved in the ascorbate–glutathione (ASC–GSH) cycle (APX, GR, ascorbate and dehydroascorbate) were investigated under salt stress in two species of genus Prosopis ( P. cineraria and P. juliflora ). Both these species are economically very important in arid and semi-arid regions of Rajasthan. For the experimentation one-week-old seedling were treated with different salt concentrations ranging from 0 to 200 mM (0, 25, 50, 75, 100, 150 and 200). The leaves were harvested after 15 and 30 days. The ascorbate content of both the species increased under salt stress. But dehydroascorbate content decrease. The activity of enzymes ascorbate peroxidase (APX) and glutathione reductase (GR) were also found to be increased under salt stress. The increase was comparatively more prominent in P. juliflora which indicates the upregulation of ascorbate-glutathione cycle is higher in P. juliflora and it plays a great role in making P. juliflora more tolerant under high salinity conditions.