Physiological and metabolomic analysis of Plantago asiatica L. in response to cadmium stress

In this study, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) and content of reduced glutathione (GSH) in Plantago asiatica L. under cadmium (Cd) stress were determined to explore the biological mechanisms of P. asiatica in response to such stress. Metabolomics was further used to screen differential metabolites, and metabolic pathway enrichment analysis was conducted. Results showed that with the increase in Cd concentration, the activities of SOD and CAT decreased significantly, POD activity increased significantly, with an overall trend of first increasing and then decreasing. GSH content showed no significant differences. There were 78 metabolites showing significant differences between the 50 mg/kg Cd stress group (YT3) and control group (YT0), including 31 up-regulated and 47 down-regulated metabolites, mainly carbohydrates and carboxylic acids. The differential metabolites were mainly enriched in 20 pathways, including three glucose metabolism pathways and three lipid metabolism pathways.