Application of zinc nanoparticles as seed priming agent improves growth and yield of wheat seedlings grown under salinity stress by enhanced antioxidants activities and gas exchange attributes

Zinc (Zn) deficiency is a serious problem for agriculture and human health. Under Zn deficient conditions, many physiological functions in plants are disturbed, and cellular homeostasis is badly affected. Under these circumstances, wheat crops produce fewer yields having low concentration of micronutrients in grains. In this modern era of nanotechnology, a possible way to achieve maximum plant growth in a sustainable manner is using nanoparticles (NPs). The present study was developed to observe the ameliorating effect of Zn nanoparticles (ZnNPs) as priming agents in wheat (Triticum aestivum L.) plants grown under saline circumstances. Five levels of ZnNPs: 0, 25, 50, 75, and 100 ppm, and two levels of salinity: 2 and 12 dS m−1, were studied. The mitigation of stress was seen in ZnNPs-applied wheat plants under salt stress, with a marked rise in total soluble sugars and total free amino acids. A significant decrease in pigment contents, total soluble proteins, and gas exchange characteristics was observed in the stress condition. Application of ZnNPs significantly improved the working of antioxidant enzymes, increased biochemical attributes, and helped regulate water relations and lipid peroxidation in wheat plants in a dose-dependent manner. It is worth mentioning that the application of ZnNPs at a rate of 100 ppm as a seed priming agent was observed to be the most distinct treatment in the accumulation of osmolytes and regulation of growth in wheat plants.