Foliar zinc oxide nanoparticles for cereal biofortification: dose–response and quality

Abstract

Zinc (Zn) deficiency remains a major nutritional constraint in populations that rely heavily on cereal-based diets, while the low phytoavailability of Zn in many agricultural soils limits the effectiveness of conventional fertilization. This review therefore evaluates whether foliar-applied zinc oxide nanoparticles (ZnO NPs) can provide a more efficient strategy for cereal biofortification while maintaining crop safety and grain quality. Specifically, we critically synthesize evidence on foliar ZnO NP uptake, translocation, biotransformation, dose-response behavior, effects on yield and grain quality, and potential ecotoxicological risks in cereal systems. The reviewed literature indicates that foliar ZnO NPs can increase grain Zn concentration, improve selected yield components, and reduc