Biomass, Physiological, and Antioxidant Activity Responses of Wheat Plants After Selenium Foliar Spray Under Water Deficit

The ability of selenium (Se) to trigger modifications in plant metabolism, thereby triggering tolerance to abiotic stresses, is well established. This research aimed to understand the following: (1) how Se supplementation in wheat plants can lead to beneficial Se concentrations in grains and straw; (2) whether the applied Se concentrations have any negative impacts on plant performance; and (3) if Se can aid wheat development under water-limited conditions. To address this, we evaluated the physiological, biochemical, and morphological effects of foliar Se application on wheat plants subjected to well-watered (WW, full irrigation) and water-deficit (WD, 25% of full irrigation) regimes. Three foliar concentrations of sodium selenate (Se) solution (0, 16, and 160 g ha−1 Se) were tested. Under WW, treatment with 160 g/ha leads to the highest Se content in straw (4253 ± 171 µg plant−1), enhanced straw biomass accumulation, and increased total soluble sugar content. WW plants treated with 16 g/ha Se were found to have the highest amounts of photosynthetic pigments and total soluble proteins. Under WD, Se treatments increased spike length, total phenols, and ortho-diphenols when compared to Se-untreated plants. In general, Se treatments increased the Se contents in both straw and grains, but with a noticeably higher accumulation in straw. Altogether, the results suggest that foliar application of 160 g/ha Se, under irrigation, is a promissory approach to enhance Se content in bread wheat.