Metabolomics Analysis of Black Phosphorus Nanosheet-Induced Toxicological Effects on Rice Seedlings

This study investigates the potential impacts of black phosphorus nanosheets (BPNSs) on rice seedlings at 0-200 mg/L. The foliar application of BPNSs at 200 mg/L could inhibit the growth of rice seedlings by damaging the antioxidant defense system. Compared to the control group, the content of malondialdehyde in the BPNS-treated leaves was reduced by 75.17%. However, the activity of superoxide dismutase was increased by 10.42%. Additionally, scanning electron microscopy revealed that the treatment with BPNSs could induce stomatal closure on the surface of rice leaves. Furthermore, metabolomic profiling indicated that the carbohydrate and amino acid synthesis pathways in the BPNS-treated seedlings were disturbed, as indicated by the significant upregulation of key metabolites, such as d-sorbitol, maltitol, l-arginine, and argininosuccinic acid. These metabolites play important roles in plant defense and the antioxidant system. Our findings provided an important insight into the further application of BPNSs on agriculture and the environment.