生长素（Auxins）和细胞分裂素（Cytokinins, CKs）能够共同调控重要的植物生长发育过程，其浓度水平的变化及稳态平衡的维持则主要依赖于激素的合成、代谢及降解。因此，建立可靠的定量分析方法，监测Auxins和CKs及重要合成代谢中间体的变化，对深入了解两类激素在植物生长发育过程中扮演的角色具有重要的意义。目前最灵敏的植物激素LC-MS/MS定量方法主要基于稳定同位素稀释法，该方法严重依赖同位素内标，不但成本高，而且很难获得多种理想内标，无法对Auxins和CKs及重要中间体实现多组分同时分析。本项目引入15N稳定同位素体内从头标记技术，建立稳定可控的模式植物标记培养体系，开发有效的前处理方法，结合LC-MS/MS技术，开展Auxins和CKs及相关代谢中间体相对定量分析方法的研究，为阐明植物激素合成代谢及相互作用机制提供更全面的信息，并为其他含氮类化合物的分析提供有益的借鉴。

Auxins and cytokinins (CKs) play important co-regulatory roles in key stages of plant growth and development, the level changing and the homeostasis maintenance of them mainly rely on their biosynthesis, metabolism and conjugation. Therefore, establishing a reliable quantification method to monitor the level changing of auxins, CKs and their key metabolic intermediates is very important to understand the roles and physiological functions of these two kinds of plant hormones in plant. The most sensitive LC-MS/MS quantification methods are mainly based on the stable isotope dilution method, which relies heavily on the stable isotope labeled internal standards (IS) that are not only costly but also hard to get access to. So, it is very difficult to accurately quantify multiple targets of auxins, CKs and key metabolites of them in an individual plant sample. In this project, a novel quantification method will be studied to quantify the levels of auxins, CKs and their key metabolites. In vivo de novo 15N stable isotope labeling technique is used to label model plant in this method, combining with highly effective pretreatment procedure and LC-MS/MS analytical techniques. The novel relative quantification analysis method will provide more comprehensive information for elucidating the mechanism of biosynthesis and metabolism of auxins and CKs, which is also very useful for analysis of other small molecule nitrogen-containing compounds.