Comparison study of zinc nanoparticles and zinc sulphate on wheat growth: From toxicity and zinc biofortification.

ZnO nanoparticles (NPs) are studied as a potential solution to alleviate Zn deficiency in human diet due to their special physicochemical properties. However, information for food quality and safety in NP-treated crops is limited. The effects of ZnO NPs and ZnSO4 on germination and growth of wheat (Triticum aestivum L.) were studied in germination and pot experiments. Zn content increased significantly, ZnO NPs were more effective than ZnSO4 at increasing grain Zn content, but less effective at increasing leaf Zn, and no ZnO NPs were detected in the wheat tissues by NP-treatments, indicated by XRD. Both ZnO NPs and ZnSO4 at moderate doses increased grain yield and biomass. Compared with control, the maximum grain yield and biomass of wheat treated with ZnO NPs and ZnSO4 were increased by 56%, 63% and 55%, 72%, respectively. ZnSO4 was more toxic than ZnO NPs at high doses as measured by the inhibitory effects in seed germination, root length, shoot length and dry biomass of seedlings. Structural damage in roots and variation in enzyme activities were greater with ZnSO4 than with ZnO NPs. ZnO NPs did not cause toxicity different from that of ZnSO4, which indicates that ZnO NPs used under the current experimental conditions did not cause Nano specific risks.