Salicylic Acid Modulates Antioxidant System, Defense Metabolites, and Expression of Salt Transporter Genes in Pisum sativum Under Salinity Stress

At present plants continuously exposed to salinity stress due to the challenging environment that has reduced the crop growth and productivity worldwide. Application of phytohormones by using seed priming method emerges as one of the most reliable and cost effective to alleviate the toxic effect of salinity stress. In this study, we evaluate the effect of seed-primed salicylic acid (SA) to reduce the adverse effect of different salt concentrations (0, 100, 200, and 300 mM NaCl) in pea (Pisum sativum L.) seedlings. After seedling emergence, percent seed germination was calculated; however, after 60 days; plants were sampled for studying the growth and photosynthetic traits, lipid peroxidation level, antioxidant activities, ions accumulation, and its sequestration. The results depicted that salinity treatments hampered overall growth performance and induced oxidative stress in a dose-dependent manner. Salinity also has negatively influence on ion accumulation as Na+ ion increased while K+ ion decreased. On the other hand, seed priming with SA significantly reduced the salinity-induced effects on the overall performance of plants, including growth and photosynthetic attributes. SA alleviated the adverse effect of salinity even at higher salinity level by inducing enzymatic and non-enzymatic antioxidant systems, soluble sugars, and proline accumulation, and regulating ion homeostasis along with up-regulation of Na+/H+ antiporters (SOS1 and NHX1). Thus, seed priming with SA shows a comprehensive role in mitigation of salinity stress and can be used as a model for promising salinity tolerant cultivation.