The mutual effects of graphene oxide nanosheets and cadmium on the growth, cadmium uptake and accumulation in rice.

The broad application and unique properties of graphene oxide (GO) nanosheets make them interact with other pollutants and subsequently alter their behaviors and toxicities. However, investigation on the effects of GO nanosheets on plant uptake of co-occurring heavy metals is scarce. We evaluated the mutual effects of cadmium (Cd) at 1 mg/L and different concentrated GO nanosheets (0, 1 and 10 mg/L) on the rice seed germination, further seedling growth, Cd uptake and accumulation in rice roots and shoots in a hydroponic system. The effects of GO were concentration dependent. GO alone at 1 mg/L showed no apparent effects, while GO alone at 10 mg/L accelerated the rice seed germination and root growth due to the improved water uptake. Cd alone showed adverse effects on the rice seed germination, which was alleviated by the presence of GO at 1 or 10 mg/L. GO at 10 mg/L also increased the membrane permeability, thus enhancing Cd uptake by rice roots and shoots. These results indicate that GO can change the effects of Cd on the rice seed germination and Cd uptake as well as accumulation in the roots and shoots of rice seedlings, which is helpful for understanding the fate and ecotoxicological impacts of both GO and Cd.