Exposure to Weathered and Fresh Nanoparticle and Ionic Zn in Soil Promotes Grain Yield and Modulates Nutrient Acquisition in Wheat (Triticum aestivum L.)

This study evaluated weathered and fresh ZnO-nanoparticles and Zn-salt effects on nutrient acquisition and redistribution in wheat. Weathered and fresh ZnO-nanoparticles and Zn-salt significantly increased grain yield by 15% and 29%, respectively. Postharvest soil acidification indicated ZnO-nanoparticles dissolved during growth. Zn was significantly bioaccumulated from both Zn types, but with low root-to-shoot bioaccumulation efficiency: 24% and 20% for weathered nanoparticles and salt, and 48% and 30% for fresh nanoparticles and salt. Grain Zn content was increased 186% and 229% by weathered nanoparticles and salt, and 229% and 300% by fresh nanoparticles and salt. Shoot-to-grain translocation efficiency was high: 167% and 177% for weathered nanoparticles and salt, and 209% and 155% for fresh nanoparticles and salt. However, Zincon assay indicated grain Zn does not exist as ions. This study demonstrates that ZnO-nanoparticles and Zn-salt vary in their effects on nutrient acquisition in wheat, with relevance for biofortification of Zn for human nutrition.