Enhancing Wheat Growth and Yield through Salicylic Acid-Mediated Regulation of Gas Exchange, Antioxidant Defense, and Osmoprotection under Salt Stress

Salinity is a major challenge for agricultural productivity, adversely affecting crop growth and yield. In recent years, various techniques have been developed to increase crop tolerance to salinity, including seed priming. This study was carried out to assess the effects of salicylic acid (SA) priming (0-, 10- and 20-mM) in comparison with hydropriming on growth, physio-biochemical activities, and yield of two wheat varieties (AARI-11 and Ujala-15) under 0- and 170-mM sodium chloride (NaCl) toxicity. The exposure of wheat plants to NaCl led to a significant reduction in various growth factors, including fresh weight (40%), total chlorophyll (39%), stomatal conductance (42%), shoot Ca2+ (39%), and 1000-grain weight (34%). In contrast, salt stress triggered the activities of POD, SOD, CAT, glycine-betaine, phenolics, and proline. The application of 20 mM SA through seed priming was found to greatly improve the fresh root weight, chlorophyll b, POD activities, shoot Ca2+, and overall yield (up to 71, 66, 35, 57, and 44%, respectively) under salt stress. While hydropriming also enhanced wheat tolerance to salinity.