Phytotoxicity of Silver Nanoparticles to Peanut (Arachis hypogaea L.): Physiological Responses and Food Safety

In the present study, we investigated the effects of silver nanoparticles (Ag NPs) on peanut (Arachis hypogaea L.) at physiological and biochemical levels as well as the impacts on peanut yield and quality. Peanuts were cultivated in sandy soil amended with different doses of Ag NPs (50, 500, and 2000 mg·kg–1) for 98 days. Physiological parameters including plant biomass, height, grain weight, and yield suggested that Ag NPs could result in severe damages in plant growth. At the biochemical level, Ag NPs did not change the predominant isozymes of each antioxidant enzyme but significantly elevated the amounts of antioxidant isozymes as compared to those of the control, and the antioxidant enzyme activities were consistent with the elevation of isozymes. Ag concentrations exhibited a dose–response fashion in peanut tissues with increasing exposure doses of Ag NPs. The evidence of Ag NPs in the edible portion of peanuts was confirmed by transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy (EDS). Additionally, alteration of the contents of fatty acids in peanut grains upon exposure to different doses of Ag NPs indicated that metal-based NPs could impact crop yield and quality. Taken together, our results suggested that the concerns over how to efficiently and safely apply nanoparticle incorporated products in agriculture and how to control their potential impact on the food safety and food quality should draw more attention as NPs themselves could be taken up by crops and humans exposed to them through food consumption.