Enhancement of Rice Zinc Content Using Green Synthesized ZnO-NPs by Foliar and Nano-Priming Applications

Zinc oxide nanoparticles (ZnO-NPs) can enhance zinc bioavailability in plants, improving crop nutritional quality and addressing global zinc deficiency. This study aimed to investigate the effects of zinc oxide nanoparticles (ZnO-NPs), obtained by a green synthesis method, on the growth, yield parameters, and zinc content of rice plants. In the study, two different application strategies of ZnO-NPs on rice plants were evaluated, i.e., foliar spray and seed priming. To compare the effects of these application strategies, rice plants were treated with ZnO-NPs at two different concentrations, 25 mg/L and 50 mg/L. Effects of ZnO-NPs on plant growth (shoot and root length, fresh and dry mass), chlorophyll and carotenoid content, grain yield and zinc content were investigated. The results showed that both ZnO-NP application methods increased rice growth and yield, especially the combined method (seed priming + foliar spray) provided the highest efficiency. It was observed that seed zinc content was increased up to 10% by seed priming method and foliar spray application increased the zinc content up to 23% while the combination of seed priming and foliar spray increased zinc content up to 122%. In general, applications at 50 mg/L concentration increased more than 25 mg/L. These results indicate that ZnO-NPs can be an effective tool for zinc deficiency management in agricultural practices and can improve the yield and nutritional content of staple foods such as rice.