To elucidate the responses of organic acids secreted by the roots of Thinopyrum ponticum under salt stress and their interactions with root traits and rhizosphere soil physicochemical properties， a controlled experiment with four salinity treatments was established： control， mild， moderate and severe salt stress （with soil salt contents of 0%， 0.2%， 0.4%， and 0.6% w/w， respectively）. Untargeted metabolomics was employed to analyze relative abundance variations and regulatory mechanisms of organic acids in root exudates. The results demonstrated that salt stress significantly decreased the secretion of organic acids including 1-hydroxy-2-naphthoic acid， succinic acid， homogentisic acid， phenylpyruvic acid and indolelactic acid （P<0.05）， while significantly enhancing the secretion of phenoxyacetic acid （P<0.05）. However， no significant effects on the secretion of 3-hydroxybutyric acid and shikimic acid. Principal coordinate analysis （PCoA） revealed significant differences in root-secreted organic acid profiles between control and salt-stressed treatments （mild， moderate and severe salinity） （P<0.05）. Correlation analysis demonstrated that soil salinity， electrical conductivity， water content， and pH were key determinants influencing root organic acid secretion. Path analysis further revealed that salt stress promoted phenoxyacetic acid secretion through soil salinization-mediated suppression of root morphological traits. These findings provide a theoretical basis for the in-depth analysis of the physiological mechanisms of plant salt tolerance.

Salinization  /  Salt tolerance mechanism  /  Rhizosphere effect  /  Root exudates