镉胁迫对丹参生理特性和代谢特征的影响

采用盆栽实验以及液相色谱-质谱联用技术，对镉(Cd)胁迫下丹参(Salvia miltiorrhiza Bunge)的生理和代谢特征进行研究。结果显示：Cd胁迫下丹参根中的Cd、脯氨酸和可溶性蛋白含量均显著增加；丙二醛(Malondialdehyde，MDA)含量显著下降；还原型谷胱甘肽(Glutathione，GSH)含量和超氧化物歧化酶(Superoxide dismutase，SOD)活性变化不显著；过氧化物酶(Peroxidase，POD)活性显著下降，但过氧化氢酶(Catalase，CAT)活性显著增加。同时也发现丹参代谢物含量发生了变化，共筛选出51个差异标志代谢物(主要是有机酸和氨基酸)；L-脯氨酸和L-组氨酸的差异倍数(Fold change, FC)均大于2.5，是上调较多的氨基酸；3,4,5-三甲氧基苯甲酸和迷迭香酸FC值均大于5，是上调较多的有机酸；Cd与差异标志代谢物(尤其是氨基酸和有机酸)呈显著正相关。研究结果说明丹参可积累一定量的Cd，高浓度的Cd胁迫可引起丹参膜脂过氧化，限制其抗氧化酶的活性，影响其代谢过程。丹参主要通过调节氨基酸和有机酸代谢，上调L-脯氨酸、L-组氨酸、3,4,5-三甲氧基苯甲酸和迷迭香酸抵御Cd胁迫。

Effects of cadmium on physiological characteristics and metabolic profiles of Salvia miltiorrhiza Bunge

The effects of cadmium (Cd) on the physiological indices and metabolomics of Salvia miltiorrhiza Bunge were investigated by pot experiments. Results showed that Cd stress significantly enhanced Cd, proline, and soluble protein content, decreased malondialdehyde (MDA) content (P < 0.05), increased catalase (CAT) activity, and inhibited peroxidase (POD) activity, with GSH contend and superoxide dismutase (SOD) activitivity showing no significant differences between the control and Cd stress group in S. miltiorrhiza roots. The metabolite profiles differed between the two groups, with 51 discriminating metabolites (mainly organic acids and amino acids) identified, which were mainly involved in amino acid and organic acid metabolism. The fold-change (FC) values of L-proline and L-histidine were greater than 2.5, and the FC values of 3,4,5-trimethoxybenzoic acid and rosmarinic acid were greater than 5, and they were the most up-regulated. There were significant positive correlations between Cd and the discriminating metabolites (especially amino acids and organic acids). These results revealed that S. miltiorrhiza accumulated a certain amount of Cd, and high levels of Cd stress led to peroxidation of membrane lipids, inhibition of antioxidant enzyme activities, and effects on the metabolomes of S. miltiorrhiza. Furthermore, S. miltiorrhiza resisted Cd stress mainly by regulating the metabolism of amino acids and organic acids, and up-regulating L-proline, L-histidine, 3,4,5-trimethoxybenzoic acid, and rosmarinic acid.