Salicylic acid and proline enhance water use efficiency, antioxidant defense system and tissues' anatomy of wheat plants under field deficit irrigation stress

Salicylic acid or proline enhances plant performance and encourages resistance to abiotic stress in plants. This investigation tests the influence of soaking kernels in salicylic acid (0.1 mM) or proline (10 mM) on the growth and performance of wheat plants grown in open field under full irrigation (100% of ETc) or deficit irrigation (50% of ETc). The results revealed that plants under field deficit irrigation (FDI) stress showed a decline in growth, kernel yield, relative water content, total content of chlorophylls and carotenoids, as well as negative changes in the anatomy of leaf and stem. Addition of salicylic acid or proline notably increased water use efficiency (WUE) and mitigated the stress created by FDI. Field deficit irrigation stress greatly increased electrolyte leakage, total soluble phenols, proline, and total soluble sugar contents and activities of enzymes SOD, CAT, and POX. Salicylic acid was the more efficient in mitigating FDI stress than proline. The results conclude that salicylic acid, as a growth regulator, could be used to alleviate the negative effect of limited water-availability in soil on wheat as well as improving the growth and yield of the crop.