Abstract
Among crops, Hordeum vulgare L. (barley) is one of the most economically important species, considered as an excellent model for studies of agronomy, plant physiology and abiotic stress, with a rapid growth rate and a high adaptability to various habitats. Ascorbic acid (AsA), also referred to as vitamin C, is a major nonenzyme antioxidant in plants and plays an important role in mediating certain oxidative stresses caused by biotic and abiotic stress. Therefore, a pot experiment was conducted to investigate the effect of different levels of AsA (0, 30 and 60 mM) in H. vulgare using two specific salinity levels, 0 and 150 mM. The results from the present study showed that the high soil salinity concentration decreased plant growth and biomass and photosynthetic pigments in H. vulgare thus elevating the generation of reactive oxygen species (ROS), suggesting that high NaCl concentrations induce oxidative stress in H. vulgare. Moreover, the enzymatic activities of superoxidase dismutase (SOD) and peroxidase (POD) came into play to reduce salinity stress and showed that H. vulgare could tolerate low levels of salt stress, i.e., 150 mM. It was also noticed that exogenous application of AsA considerably increased plant height, plant leaf area, sheet number, tillers number, plant fresh and dry biomass, photosynthesis pigments, and reduced the oxidative stress (H2O2 and MDA) in plants which in turn reduced the enzymatic (SOD and POD) and non-enzymatic antioxidants (GSH and AsA). Research findings, therefore, suggested that AsA application can ameliorate salinity stress in H. Vulgare and resulted in improved plant growth and composition under abiotic stress condition, as depicted by reduced the genetaion of ROS.