目的 研究外源性镉（Cd）对三七主要药效成分合成中关键酶2，3-氧化鲨烯被达玛烯二醇合成酶（DS）和细胞色素P450单加氧酶（P450）基因表达的影响。方法 设置9个Cd的质量分数梯度（0.0、0.1、0.3、0.6、1.0、3.0、6.0、10.0、30.0 mg/kg）分别对三七进行胁迫实验，两年后采集成熟三七，通过qRT-PCR检测手段对其根部DS及P450基因进行表达量测定，并以GAPDH基因作为内参基因进行DS及P450基因相对表达量的计算，通过相关性分析计算DS和P450基因表达与三七主要药效成分三七皂苷R₁、人参皂苷Rb₁、人参皂苷Rg₁以及总皂苷的相关性。结果 Cd在低质量分数下能促进DS的表达，高质量分数下抑制DS的表达；随着Cd质量分数的增加，对P450表达的抑制作用更加明显；而DS和P450基因表达与三七主要药效成分三七皂苷R₁、人参皂苷Rb₁、人参皂苷Rg₁以及总皂苷无显著相关性（P>0.5）。结论 重金属Cd对三七药效成分中关键酶DS和P450基因表达影响不同，对同一种酶，Cd质量分数不同其影响也不同。但主要药效成分并未因此受明显影响。

Objective To learn the effect on the expression of key enzymes DS and P450 genes in the medicinal composition synthesis of Panax notoginseng under exogenous Cadmium (Cd). Methods Nine treatments of Cd (0.0, 0.1, 0.3, 0.6, 1.0, 3.0, 6.0, 10.0, and 30.0 mg·kg^-1) was added to the cultivated soil of Panax notoginseng, respectively. Two years later, mature Panax notoginseng was sampled. The expression of DS and P450 genes in root was detected using qRT-PCR method, and GAPDH gene was taken as the reference genes to calculate the relative expression of DS and P450 genes. The correlation between expression of key enzymes genes and main medicinal composition (notoginsenoside R₁, ginsenoside Rb₁, ginsenoside Rg₁, and total saponins) was determined by correlation analysis. Results Cd increased DS expression in low concentration, and inhibited in high levels, while with the adding Cd increasing, the P450 expression decreased significantly. However, the expression of DS and P450 genes didn't show good correlation with notoginsenoside R₁, ginsenoside Rb₁, ginsenoside Rg₁, and total saponins (P>0.5). Conclusion Cd can affect the expression of DS and P450 genes in different ways and for the same gene, the expression is also various in different Cd levels. However, the main medicinal composition content wasn't influenced consequently.