Cadmium (Cd) can interfere with plant gene expression, change the content of metabolites and affect plant growth. In this study, untargeted metabolomics (LC-MS) and RNA-Seq sequencing were performed on root tissues of Pistia stratiotes exposed to Cd stress. The results showed that cadmium stress affected the accumulation and transport of cadmium in plants and increased the content of soluble sugar, the activities of ascorbate peroxidase (APX), and peroxidase (POD) by 34.89%, 41.45%, and 6.71% on average, and decreased the activity of superoxide dismutase (SOD) by 51.51% on average. At the same time, the contents of carotenoid, chlorophyll a, and chlorophyll b decreased by 29.52%, 20.11%, and 13.14%, respectively, Thus affecting the growth and development of plants. Metabolomic analysis showed that Cd stress affected eight metabolic pathways, involving 27 differentially expressed metabolites, mainly including unsaturated fatty acids, amino acids (phenylalanine), nucleotides, sulfur compounds, and flavonoids. By transcriptome analysis, a total of 3107 differentially expressed genes (DEGs, 2666 up-regulated genes, and 441 down-regulated genes) were identified, which were mainly involved in four pathways, among which glutathione metabolism and lignin biosynthesis were the key metabolic pathways. In conclusion, this study reveals the metabolic and transcriptional response mechanisms of P. stratiotes to Cd stress through multi-omics, providing the theoretical basis for the phytoremediation of water contaminated by Cd.

镉（Cd）能干扰植物基因表达，改变代谢物含量，影响植物生长。在这项研究中，对Pistia stratiotes的根组织进行了非靶向代谢组学 (LC-MS) 和 RNA-Seq 测序暴露于 Cd 胁迫。结果表明：镉胁迫影响植物体内镉的积累和转运，可溶性糖含量、抗坏血酸过氧化物酶（APX）和过氧化物酶（POD）活性平均提高34.89%、41.45%和6.71%，并使超氧化物歧化酶 (SOD) 的活性平均降低 51.51%。同时，类胡萝卜素、叶绿素a、叶绿素b含量分别下降29.52%、20.11%、13.14%，从而影响植物的生长发育。代谢组学分析表明，Cd胁迫影响了8条代谢途径，涉及27种差异表达的代谢产物，主要包括不饱和脂肪酸、氨基酸（苯丙氨酸）、核苷酸、硫化合物和类黄酮。通过转录组分析，共鉴定出3107个差异表达基因（DEGs、2666个上调基因和441个下调基因），主要涉及4条途径，其中谷胱甘肽代谢和木质素生物合成是关键代谢途径。总之，这项研究揭示了代谢和转录反应机制P. stratiotes通过多组学对 Cd 胁迫的研究，为 Cd 污染水体的植物修复提供了理论基础。