紫花苜蓿种子萌发过程中内源激素含量的动态变化

Dynamics of endogenous hormones during seed germination in alfalfa

摘要:

【目的】植物内源激素在调控种子休眠与萌发过程中具有极其重要的作用。【方法】利用高效液相色谱串联质谱（HPLC-MS/MS）方法，测定不同萌发时期紫花苜蓿（Medicago sativa）种子中生长素（IAA、ME-IAA）、脱落酸（ABA）、赤霉素（GA₃）、玉米素核苷（ZR）及茉莉酸（JA、JA-ILE 和 H2JA）含量变化情况。【结果】紫花苜蓿种子萌发过程中，ABA、IAA 及 JA 含量均维持在较高水平， GA₃、ZR、JA-ILE 及 H2JA 含量全程较低。其中 ABA、IAA、JA、JA-ILE 含量均呈现下降的变化趋势；GA₃含量由干燥种子进入吸胀过程急剧上升，萌发开始后开始下降，到萌发后期出现小幅上涨； ME-IAA 含量呈现出先升后降再升的趋势，在种子开始萌动及萌动后期升高；ZR 和 H2JA 表现一致， 均呈先升高后降低的趋势，具体表现为种子吸胀进入萌动时含量升高，萌动开始后开始降低；IAA/ ABA 比值在种子萌发进程中呈上升趋势；GA₃/ABA 比值呈现出“升-降-升”的变化趋势，种子萌动后期达最大值；ZR/ABA 比值则表现出先升后降的趋势，在种子进入萌动中期时达到最大值。【结论】 ABA 和 GA₃虽是参与调节种子休眠和萌发的主要内源激素，但它们并不总是起决定性作用，其他内源激素，如 IAA、ME-IAA、JA、JA-ILE、H2JA 和 ZR，在萌发过程中同样也扮演着重要的作用。

Abstract:

【Objective】Endogenous plant hormones play an extremely important role in regulating the dormancy and germination of seeds.【Method】 In this study，we determined the changes of growth hormones （IAA，MEIAA），abscisic acid （ABA），gibberellin （GA₃），zeatin nucleoside （ZR） and jasmonic acid （JA，JA-ILE and H2JA） contents in alfalfa seeds during different germination periods by high performance liquid chromatography tandem mass spectrometry （HPLC-MS/MS）.【Result】 The results showed that the contents of ABA，IAA and JA were main‐ tained at a higher level during the germination of alfalfa seeds，while the contents of GA₃，ZR，JA-ILE and H2JA were lower throughout. Among the hormones，ABA，IAA，JA and JA-ILE contents showed a decreasing trend； GA₃ content rose sharply from the dry seeds into the process of uptake，started to decline after the beginning of germi‐ nation，and a small increase at the late germination stage. The ME-IAA content showed a trend of rising，then fall‐ ing，then rising again，and were higher at the beginning and late germination of seeds. The ZR and H2JA showed the same trend，both showed an increase and then a decrease，specifically when the seeds sucked up into germination，and began to decrease after the start of germination. IAA/ABA ratio showed an increasing trend with the process of seed germination. GA₃/ABA ratio showed a trend of rising ‐decreasing ‐rising and reached the maximum value at the late stage of seed germination. The ZR/ABA ratio showed firstly an increasing trend and then decreasing trend，andreached the maximum value when the seeds entered the middle stage of germination.【Conclusion】 In conclusion，al‐ though ABA and GA₃ are the main endogenous hormones involved in regulating seed dormancy and germination， they do not always play a decisive role，and other endogenous hormones，such as IAA，ME-IAA，JA，JA-ILE， H2JA and ZR，also play an important role in the germination process.