Synthesis, characterization and application of ZnO nanoparticles for improved growth and Zn biofortification in maize

Zinc (Zn) deficiency is common on calcareous soils due to fixation with soil components and precipitation with other ions. ZnO nanoparticles (ZnO NPs) may serve a better source of Zn for improved growth and biofortification in maize grains. Pot and field experiments were conducted to evaluate the effect of ZnO nanoparticles in comparison with conventional Zn fertilizer (ZnSO4) on growth and grain Zn contents of maize. In both experiments, Zn application improved growth and physiological parameters of plants; however, maximum improvement was observed in treatments receiving ZnSO4(soluble) or ZnO nanoparticles (insoluble source of Zn). Application of ZnO nanoparticles also improved Zn concentration in shoots as well as in grains in field experiment. In field experiment, Zn partitioning was also calculated and interestingly it is found that Zn concentration at maturity stages was reduced in stem and mature leaves. Maximum Zn concentration (similar to 80 mg kg(-1)) was observed in young leaves at vegetative growth stage in treatments receiving ZnO nanoparticles. Foliar applied ZnO NPs showed maximum increase in grain Zn concentration (82%). It is concluded that ZnO NPs improved maize growth, yield and grain Zn contents. Being cheaper and efficient source, it can be used for Zn biofortification.

Automated summary

The study demonstrates that ZnO nanoparticles significantly improve maize growth and grain zinc content, especially benefiting the increase in Zn concentration in grains.