盐胁迫对长穗偃麦草根系分泌有机酸的影响OA

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 experi-ment 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-naph-thoic acid,succinic acid,homogentisic acid,phenylpyruvic acid and indolelactic acid(P<0.05),while signifi-cantly enhancing the secretion of phenoxyacetic acid(P<0.05).However,no significant effects on the secre-tion of 3-hydroxybutyric acid and shikimic acid.Principal coordinate analysis(PCoA)revealed significant differ-ences 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 mor-phological traits.These findings provide a theoretical basis for the in-depth analysis of the physiological mecha-nisms of plant salt tolerance.