黄芪幼苗根系生长发育与GR24和IAA的关系

Relationship between root growth and development of Astragalus seedlings and GR24 and IAA

关键词:  黄芪, 主根, 侧根, 独脚金内酯, 生长素, 基因表达

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

摘要:

为探究独脚金内酯和生长素对黄芪根系生长发育的影响,该研究以膜荚黄芪和蒙古黄芪幼苗为材料,在种子萌发袋中添加不同浓度GR24和IAA(2 μmol·L^-1 GR24、5 μmol·L^-1 IAA和2 μmol·L^-1 GR24+5 μmol·L^-1 IAA),7 d后检测黄芪幼苗主根长和侧根数,并测定内源激素含量、生长素和独脚金内酯相关基因表达量的变化。结果表明:(1)GR24处理显著促进黄芪主根生长。(2)IAA处理下主根生长受到抑制,侧根数明显增加。(3)GR24+IAA处理下主根的生长同样受到抑制,膜荚黄芪侧根数较IAA处理下减少,说明GR24有抑制IAA对侧根发育的诱导作用,但不能缓解IAA对黄芪主根生长的抑制。(4)3种处理下黄芪幼苗根系内源激素含量、生长素和独脚金内酯相关基因表达量发生了显著变化,说明GR24和IAA对黄芪幼苗主根长和侧根数的影响可能与生长素和独脚金内酯相关基因表达及内源激素水平的变化有关。该研究结果初步阐明了黄芪幼苗根系生长发育与GR24和IAA之间的关系,为黄芪规范化育苗和幼苗质量控制提供理论依据,对进一步探索独脚金内酯和生长素调控黄芪根系生长发育的分子机制具有一定的意义。

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·L^-1 GR24, 5 μmol·L^-1 IAA and 2 μmol·L^-1 GR24+5 μmol·L^-1 IAA). 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.