黃芪幼苗根系生長發育與GR24和IAA的關系

黃曉宇　龐娟　 陳貴林

摘要：為探究獨腳金內酯和生長素對黃芪根系生長發育的影響，該研究以膜莢黃芪和蒙古黃芪幼苗為材料，在種子萌發袋中添加不同濃度GR24和IAA（2 μmol·L1GR24、5 μmol·L1IAA和2 μmol·L1GR24+5 μmol·L1IAA），7 d后檢測黃芪幼苗主根長和側根數，并測定內源激素含量、生長素和獨腳金內酯相關基因表達量的變化。結果表明：（1）GR24處理顯著促進黃芪主根生長。（2）IAA處理下主根生長受到抑制，側根數明顯增加。（3）GR24+IAA處理下主根的生長同樣受到抑制，膜莢黃芪側根數較IAA處理下減少，說明GR24有抑制IAA對側根發育的誘導作用，但不能緩解IAA對黃芪主根生長的抑制。（4）3種處理下黃芪幼苗根系內源激素含量、生長素和獨腳金內酯相關基因表達量發生了顯著變化，說明GR24和IAA對黃芪幼苗主根長和側根數的影響可能與生長素和獨腳金內酯相關基因表達及內源激素水平的變化有關。該研究結果初步闡明了黃芪幼苗根系生長發育與GR24和IAA之間的關系，為黃芪規范化育苗和幼苗質量控制提供理論依據，對進一步探索獨腳金內酯和生長素調控黃芪根系生長發育的分子機制具有一定的意義。

關鍵詞： 黃芪， 主根， 側根， 獨腳金內酯， 生長素， 基因表達

中圖分類號：Q945

文獻標識碼：A

文章編號：10003142（2022）05084510

Relationship between root growth and development

of Astragalus seedlings and GR24 and IAA

Abstract：In order to explore the effects of strigolactones and auxin on the growth and development of Astragalus roots， Astragalus membranaceus ?and A. membranaceus var. mongholicus seedlings were put into seed germination bag with different concentrations of GR24 and IAA （2 μmol·L1GR24， 5 μmol·L1IAA and 2 μmol·L1GR24+5 μmol·L1IAA）. Primary root length and lateral root number of Astragalus seedlings were measured， and endogenous phytohormones， the expression levels of auxin and strigolactone related genes were determined after seven days treatment. The results were as follows： （1） GR24 treatment could significantly promote the growth of primary roots of Astragalus. （2） The growth of primary roots was inhibited under IAA treatment， and the number of lateral roots was significantly increased. （3） The growth of primary roots under GR24+IAA treatment was also inhibited， the number of lateral roots of A. membranaceus was reduced compared with that under IAA treatment， indicating that GR24 can inhibit the induction of IAA to lateral root development， but can not alleviate the inhibition of IAA to primary root growth. （4） The levels of endogenous hormones， auxin and strigolactone related gene expression in the root of Astragalus seedlings under the three treatments were changed significantly， indicating that the effects of GR24 and IAA on primary root length and lateral root number of Astragalus seedlings may be related to these changes. The results preliminarily clarify the relationship between the root growth and development of Astragalus seedlings and GR24 and IAA， and provide a theoretical basis for the standardized breeding and seedling quality control of Astragalus. It also has certain significance to further explore the molecular mechanism of strigolactones and auxin regulating the growth and development of Astragalus root.

Key words： Astragalus， primary roots， lateral roots， strigolactones， auxin， genes expression

生長素是最早發現且目前研究最多的一類植物激素，一直以來被認為是參與植物根系生長發育最關鍵的核心植物激素（Saini et al.， 2013; Wei et al.， 2016）。生長素的分布、極性運輸和信號轉導決定著植物根系的形態建成（Saini et al.， 2013）。生長素在植物地上部幼嫩組織合成后，通過維管組織運輸到根部（Ljung et al.， 2005; Teale et al.， 2006）。……