Translocation of CdS nanoparticles in maize (Zea mays L.) plant and its effect on metabolic response.

Cadmium sulfide nanomaterials are of great concern because of their potential toxicity and unavoidable releases due to multiple commercial applications of nanoparticles (NPs). Commercial NPs act as mediators of damage to plant cells and pose potential toxicity to plants and human health. In the current study, investigated the phytotoxicology, absorption, translocation, antioxidant enzyme activity, and metabolic profiles of maize (Zea mays L.) seedlings exposed to different hydroponic treatments for fifteen days. The different concentrations of CdS NPs (3, 15, 30, 50, and 100 mg/L), 0.3 mg/L Cd ions, and unexposed control were performed in treatments. The results indicated that CdS NPs could present phytotoxic effects on seed germination and root elongation. Compared to the control, the CdS NPs dramatically reduced the shoots and root biomass, as well as the shape of the roots. Transmission electron microscopy and energy-dispersive mapping confirmed that CdS NPs could penetrate the maize root epidermis and bioaccumulate in the shoots with high concentrations. According to metabolomics studies, exposure to CdS NPs and Cd ions would result in metabolic disruption. Based on the statistical analysis, 290 out of 336 metabolites (86.30%) were obviously inhibited. The findings of this study demonstrated possible risks of emerging potential toxic NPs, and the release of these NPs to environment is a serious concern for agricultural activities.