Uptake, Accumulation and Translocation of Engineered Nanomaterials in Agricultural Crops.

Development and use of engineered nanoparticles (ENPs) have been rapidly increasing and they are also being used in agricultural and food industry. Release of ENPs to the environment such as soil and water causes concern over their possible uptake by and accumulation in agricultural crops due to their toxicity. In this study, gold (Au) and copper oxide (CuO) nanoparticles (NPs) were used to examine their uptake by and translocation in rice and corn. For Au NPs, the amount of uptake and translocation clearly depended on plant species and the type of surface charge on Au NPs, with negatively charged Au NPs being accumulated the most and positively charged Au NPs the least. The CuO NPs inhibited the growth and development of corn seedlings, but CuO bulk particles and amount of Cu²⁺ ions dissolved from CuO NPs had no obvious effect on corn growth. Furthermore, CuO NPs were not only transported from roots to shoots and leaves via xylem, but also they were translocated from shoots back to roots via phloem. This study provides strong evidence for potential uptake and bioaccumulation of ENPs in agricultural crops.