Abstract
Antimony (Sb) has been reported to be largely taken up and accumulated by plants, although it is unessential for plant growth. The translocation and phytotoxicity of Sb in plant tissues greatly depend on the redox chemistry states. A number of studies have investigated the phytotoxicity of enginered nanoparticles (ENPs) to various vascular plants. However, the coexposure of ENPs with Sb has not been well understood, as well as the potential interactions between ENPs and Sb species relating to their uptake and translocation in plants. In this study, three common metal oxide nanoparticles (CeO2, TiO2, and CuO NPs, 50 mg L–1) with different redox properties were selected and coexposed with Sb (trivalent (III) and pentavalent (V) states, 50 mg L–1) to soybean seedlings. The results suggested that the accumulation of Sb(III) in roots was significantly increased by CeO2 (by 36.7%) and CuO NPs (by 58.8%) respectively, while no significant effects were caused by TiO2 NPs. In contrast, both Sb(III) and Sb(V) significantly decreased the accumulation of CeO2 NPs in roots which resulted in only 2.9% and 13.02% of Ce accumulation compared to a single exposure of CeO2 NPs. However, the accumulations of both TiO2 NPs and CuO NPs in roots and leaves were significantly increased. In addition, ENPs and Sb displayed mutual antagonism or synergistic effects on plant biomass amounts, malondialdehyde (MDA) contents, and enzyme activities. These results suggested that the potential interactions between Sb species and ENPs and the different impacts of coexposure treatments on soybeans might depend on Sb initial oxidation states and ENPs properties. This study provided another insight to understand the accumulation and transfer of Sb and ENPs in edible plants and human exposure risks in these environments.