▎ 摘　　要

To understand environmental impacts of carbon-based nanomaterials,a systematic study on graphene, which is a representative carbon-based nanomaterial, is needed. Phytotoxicity studies on higher plants are needed to characterize the toxicity of graphene. We studied the effects of graphene (at 0, 5, 50, 100, and 200 mg/L concentrations) on antioxidant enzyme activity, chlorophyll content and malondialdehyde (MDA) content in rice seedlings. Superoxide Dismutase (SOD), Peroxidase (POD), and Catalase (CAT) were reduced by 5 mg/L graphene and the difference in MDA was not significant. The same level of graphene produced significant increase in chlorophyll content. Increased graphene concentrations were associated with higher SOD, POD, and CAT activities, with increased MDA and decreased chlorophyll contents. These results indicated the potential toxicity of graphene in rice seedlings and suggested the possible utility for 5 mg/L graphene to enhance growth in rice seedlings.