水涝胁迫下芝麻内源激素及表型响应

Sesame phytohormone and phenotype response to waterlogging

为探究芝麻内源激素及其表型对水涝胁迫的响应特征,在盛花期盆栽条件下,对两个耐湿水平差异显著的基因型ZZM2541(耐湿)和鄂芝2号(敏感)进行水涝胁迫,利用液相色谱-串联质谱法(LC-MS/MS)测定两个组织(顶端倒三叶和茎尖组织)内源IAA和ABA在胁迫3h、9h、15h及撤水后20h的含量变化,另外分析两种基因型在连续水涝胁迫72h脱落叶片数、植株高度以及顶端倒三叶叶绿素含量变化。结果表明,两种基因型顶端倒三叶中IAA含量均在胁迫开始至胁迫9h后逐渐上升、而后下降,茎尖IAA含量在胁迫9h后仍有所升高。整个过程中ZZM2541两个组织的IAA含量都明显高于鄂芝2号。ABA含量在不同耐湿基因型的两个组织中均表现为在水涝开始至15h持续下降,撤水后急速上升,且耐湿基因型叶片ABA含量上升速度比敏感基因型快,在撤水后20h耐湿材料的两个组织ABA含量是敏感材料的2倍左右。相对而言,耐湿基因型的株高生长和叶绿素含量受胁迫的影响较小,但有更多的叶片脱落,这可能是一种保护机制。本研究显示水涝胁迫初期(9h以内)IAA含量和撤水后20h的ABA含量可明显区分上述两种不同基因型。

To explore the phytohormone and phenotype responses to waterlogging stress in sesame,tolerant ZZM2541 and susceptible Ezhi 2 were treated with waterlogging for 3h,9h and 15 h at flowering stage. By liquid chromatography- tandem mass spectrometry（ LC- MS / MS）,the top 3rd leaves and stem tips of these 2 genotypes were investigated for indole acetic acid（ IAA） and abscisic acid（ ABA） contents at each time point and 20 h after drainage. Phenotype changes were analyzed including shedding leaves and plant heights,and the contents of chlorophyll in the top 3rd leaves before and 72 h after the initial of waterlogging. Results showed endogenous IAA contents in the top 3rd leaves were both increased during the first 9h of waterlogging,and started to decrease after 9h.But the contents were continued to increase in stem tips after 9h of waterlogging. Especially,IAA content in ZZM2541 was always higher than that of Ezhi 2 throughout the stress. The contents of ABA in both genotypes decreased continuously until 15 h of waterlogging and then increased,although they increased more rapidly in the tolerant genotype ZZM2541 and reached about twice of the susceptible one after drainage. Relatively,the plant height and chlorophyll content in the top 3rd leaves（ with more leaf abscission） of tolerant ZZM2541 were less affected by waterlogging stress,which could be a protective mechanism. In summary,IAA content at the initial stage of waterlogging（ within 9h） and ABA at 20 h after drainage could be used to differentiate the above 2 genotypes.