Zinc oxide seed priming enhances drought tolerance in wheat seedlings by improving antioxidant activity and osmoprotection.

Drought can affect all growth stages and has a significant effect on seed germination, which affects all physiological and metabolic germination processes. It also leads to dehydration, which increases the oxidation of lipids and membranes and disrupts the functioning of biomolecules in plants. Zinc is an essential element for several enzymes involved in metabolism, cell elongation, preservation of the strength and integrity of cell membranes, seed development, and resistance to environmental stress. A pot experiment was conducted to determine how ZnO seed priming, either in the form of ZnO NPs (nanopriming) or ZnO bulk priming (60 mg L), counteracts the negative impacts of drought at different levels (80% and 60% FC) on wheat (Triticum aestivum L.) seedlings at the seedling stage. A recent experiment revealed that seed priming agents significantly mitigate the negative effects of drought stress, especially at 60% FC, by positively influencing various parameters of wheat seedlings. Notably, the POD activity increased by 91.8% and 289.9% for the shoots, 218.6% and 261.6% for the roots, the phenolic content increased by 194.4% for the shoots and 1139.6% for the roots, the HO scavenging percentage increased by 124.9% and 135.4% for the shoots and 147.6% for the roots, and the lipid peroxidation inhibition percentage increased by 320.6% and 433% for the shoots. Moreover, the utilization of seed priming agents had a profound effect on free amino acids (393.8%, 502.8% for roots) and soluble carbohydrates (183.4% for roots) compared with those in stressed seedlings without priming. Experimental and computational methods (time-dependent density functional theory (TD-DFT)) were employed to perform IR and XRD analyses of the isolated molecules of the ZnO NPs/Iso. In conclusion, the application of ZnO NPs or bulk ZnO was found to create effective mechanical and physiological barriers, as confirmed by the analysis of antioxidant enzyme activities, nonenzymatic components, free radical scavenging, and osmoprotectant constituents.