Pre-exposure to gamma rays alleviates the harmful effect of salinity on cowpea plants

Soil salinity is one of the most severe factors limiting growth and physiological response in cowpea plants. In this study, the low concentrations of NaCl (25mM) increased plant growth, photosynthetic pigments content, total soluble protein content, nucleic acids contents (DNA and RNA), lipid peroxidation, non enzymatic antioxidants (anthocyanin, ascorbic acids and α-tocopherol), number of legumes per plant, number of seeds per legume, number of seeds per plants, legume length, fresh and dry weight of legumes and weight of 1000 seeds and total soluble proteins and carbohydrate contents in harvested seeds as compared to control. On the other hand, the high concentrations of NaCl (50, 100 and 200 mM) caused reduction in plant growth, photosynthetic pigments content, total soluble protein content, nucleic acids contents (DNA and RNA), all yield attributes and harvested seeds components but increased lipid peroxidation and non enzymatic antioxidants (anthocyanin, ascorbic acids and α-tocopherol). Electrophoretic studies of proteins showed three types of modifications are observed in the protein patterns of cowpea seeds, some protein bands were disappeared, other proteins were selectively increased and synthesis of new set of protein was induced. Some of these responses were observed under gamma rays and salinity treatments, while others were induced by either gamma rays or salinity. Seeds irradiation with gamma rays alleviates the adverse effect of salt stress compared to non irradiated seeds.