Abstract: To investigate the response mechanism of terpenoid root exudates to salt stress in halophytes， Elytrigia elongata was used as a model species. Gradients of NaCl solutions were applied to soil to simulate control， light， moderate， and severe salt stress conditions. A non-targeted metabolomics approach was employed to identify the profiles and relative abundances of terpenoid compounds in root exudates， and correlations between terpenoid abundance， root morphological traits， and rhizosphere soil physicochemical properties were analyzed. The results showed that compared with the control， the relative abundance of sesquiterpenes， monoterpenes， diterpenes and other terpenoids in root exudates significantly decreased by 8.61%-16.41% under light， moderate and severe salt stress treatments. Triterpenoids and triterpene saponins significantly decreased by 24.54% and 12.43% respectively only under light salt stress. Soil pH emerged as the primary factor influencing terpenoid exudation in Elytrigia elongata. As soil salinity increased， pH decreased， thereby suppressing the secretion of sesquiterpenoids， monoterpenoids， diterpenoids， and other terpenoid classes. These findings provide critical insights into the physiological mechanisms underlying plant adaptation to saline environments.

Key words: Salinization, Elytrigia elongata, Root exudates, Terpenoids

摘要： 为探究耐盐植物根系分泌萜类物质对盐胁迫的响应机制，以长穗偃麦草（Elytrigia elongata）为研究对象，在土壤中添加不同浓度的NaCl溶液，模拟对照、轻度、中度和重度盐胁迫处理，采用非靶向代谢组学技术，测定萜类根系分泌物的种类与相对丰度变化，分析萜类物质相对丰度与根系性状、根际土壤理化性质间的关系。结果表明：与对照相比，轻、中、重度盐胁迫处理下倍半萜、单萜、二萜和其他萜类根系分泌物的相对丰度显著降低8.61%~16.41%，三萜和三萜皂苷类仅在轻度盐胁迫下分别显著降低24.54%和12.43%；土壤pH是影响长穗偃麦草萜类根系分泌物的关键因子，随土壤盐度增加，土壤pH值降低，进而抑制倍半萜、单萜、二萜和其他萜类根系分泌物的分泌。本研究为深入理解植物耐盐的生理机制提供科学依据。

关键词: 盐渍化, 长穗偃麦草, 根系分泌物, 萜类