微透析法研究盐胁迫下杨树嫩茎内源激素和叶片叶绿素荧光参数的变化

Changes of Endogenous Hormones in the Tender Stems and Chlorophyll Fluorescence in the Leaves of Poplar Trees under Salt Stress by Microdialysis

采用微透析技术获得杨树质外体透析液,高效液相色谱测定盐胁迫下吴屯杨和欧美杨内源激素的动态变化,并结合叶绿素荧光参数的变化,分析对比吴屯杨和欧美杨两种杨树的耐盐性。结果表明,高盐度胁迫下吴屯杨体内脱落酸(ABA)的积累量为对照的1.3倍,而欧美杨体内ABA的积累量为对照的1.8倍;欧美杨的PSII原初光能转换效率(F v/F m)及电子传递效率(ETR)值显著低于吴屯杨,光系统破坏程度较大;欧美杨的抗盐平衡系数明显大于吴屯杨的抗盐平衡系数,说明盐胁迫下欧美杨各种激素之间的协调作用下降,生长受胁迫的抑制程度大于吴屯杨,表明吴屯杨耐盐性强于欧美杨。此方法为研究杨树质外体内的耐盐性机制和选育耐盐杨树新品种提供理论依据。

The apoplast dialysates from poplar trees were obtained using the microdialysis technique. To compare the salt tolerance of Populus ×wutunensis and Populus ×euramericana, the dynamics of their endogenous hormones were determined by high performance liquid chromatography and the difference in chlorophyll photosynthetic fluorescence parameters was analyzed under salt stress. The results showed that ABA level in P. xwutunensis under the high-concentration salt stress for fifteenth days was 1.3 times higher than that under the normal condition, while it was 1.8 times higher in P. ×euramericana under salt stress. The Fv/Fm and ETR values in P. ×euramerieana were significantly lower than those in P. ×wutunensis, indicating that the photosynthetic system of P. ×euramericana was more severely affected. Furthermore, the salt balance coefficient of P. ×euramericana is obviously bigger than that of P. ×wutunensis, suggesting that under highconcentration salt stress the coordinative capacity of hormones in P. ×euramericana was decreased and its growth was more severely inhibited by stress than that in P. ×wutunensis. Together, our results suggest that P.×wutunensis has higher salt tolerance than P. ×euramericana. Our approaches used in this study may be useful for studying the physiological mechanisms of salt tolerance in poplar apoplast and for selection and breeding salt tolerant varieties of Populus.