Foliar Application of Salicylic Acid Improved Growth, Yield, Quality and Photosynthesis of Pea (Pisum sativum L.) by Improving Antioxidant Defense Mechanism under Saline Conditions

Abstract

Pea is an important legume crop because of its higher bioactive compounds, and its seeds are famous as functional foods. However, the yield of pea is still limited because of multiple biotic and abiotic stresses which prevailed during the growth period. Saline conditions significantly hamper pea growth, yield, and quality among abiotic stresses. Salicylic acid is effective for the activation of oxidative, non-oxidative, osmolytes, and metabolites. Hence, the present study was conducted at exogenous application of salicylic acid (control, 1 µM, 2 µM, and 3 µM) to mitigate the adverse effects of salt stress (control, 25 mM, 50 mM, and 100 mM NaCl) in pea plants grown in the year 2019–2020. The aim of the present study was to evaluate pea performance under saline conditions by salicylic acid sprays. Pea growth and yield were significantly decreased at 100 mM NaCl compared with the control and other salinity levels. Moreover, the growth and yield of pea were improved under exogenous application of salicylic acid treatment at 3 µM than others. Quality traits, i.e., carotenoids, ascorbic acid, and phenolic content, were decreased at 100 mM NaCl, and these quality traits were significantly improved under salicylic acid treatment of 3 µM. Chlorophyll a, chlorophyll b, total chlorophyll, photosynthesis, and stomatal conductance were reduced at 100 mM NaCl. In contrast, photosynthetic pigments, photosynthesis, and stomatal conductance were enhanced at 3 µM salicylic acid. The increases in SOD, CAT, POD, and APX were observed at 100 mM NaCl and 3 µM salicylic acid. The current study proved that exogenous application of salicylic acid concentrations had the potential to mitigate the salinity’s adverse effects by maintaining the physiological and metabolic activities of pea plants.