Abstract: To determine the effects of waterlogging stress on leaf metabolism of alfalfa (Medicago sativa L.),metabolomics method based on liquid chromatography-mass spectrometry (LC-MS) technology was used to investigate the changes of leaf metabolites in two alfalfa varieties with different fall dormancy levels as:variety 'SK 3010’ (fall dormancy level 2.5) and 'WL 525HQ’ (fall dormancy level 8.0) under waterlogging stress. The results showed that the metabolic pathways of 'SK 3010’ were mainly concentrated in phenylalanine metabolism,tyrosine metabolism and alkaloid synthesis under waterlogging stress;while 'WL 525HQ’ was mainly concentrated in metabolism of alanine,aspartic acid and glutamate,D-amino acid metabolism,aminoacyl biosynthesis and other metabolic pathways,in which the content of metabolites such as glutamic acid,serine,glutamine and asparagine was significantly up-regulated. In conclusion,the metabolism of alanine,aspartic acid and glutamate,D-amino acid metabolism,aminoacyl biosynthesis and other metabolic pathways improved the stain resistance of alfalfa to waterlogging stress. This study could provide an important theoretical basis for the research on the different mechanisms for waterlogging tolerance of alfalfa varieties with different fall dormancy levels.

Key words: Alfalfa, Fall dormancy, Waterlogging stress, Metabolomics

摘要： 为明确渍水胁迫对不同秋眠级紫花苜蓿(Medicago sativa L.)叶片代谢的影响，本研究以两个不同秋眠级紫花苜蓿品种'SK 3010'(秋眠级2.5)和'WL 525HQ'(秋眠级8.0)为材料，通过液相色谱-质谱(LC-MS)技术的代谢组学方法测定分析了渍水胁迫下叶片代谢产物的变化。结果表明：渍水胁迫下，'SK 3010'的代谢途径主要富集在苯丙氨酸代谢，酪氨酸代谢以及生物碱合成等；'WL 525HQ'主要富集在丙氨酸、天冬氨酸和谷氨酸代谢，D-氨基酸代谢，氨酰生物合成等代谢路径，其中谷氨酸、丝氨酸、谷氨酰胺和天冬酰胺等代谢产物含量显著上调。因此，丙氨酸、天冬氨酸和谷氨酸代谢，D-氨基酸代谢，氨酰生物合成等代谢路径提高了紫花苜蓿的耐渍性，为不同秋眠级紫花苜蓿耐渍性差异机制研究提供重要理论依据。

关键词: 紫花苜蓿, 秋眠级, 渍水胁迫, 代谢组学