The Regulatory Mechanism Of Auxin And Strigolactone On Roots Development Of Astragalus Membranaceus(Fisch.)bunge Seedlings

Root development is regulated by a variety of factors,among which auxin and strigolactone are involved in the complex network regulation mechanism of root development.As one of the bulk Chinese medicinal materials,Astragalus membranaceus is used as a root.The length of the main root and the number of branches are important criteria for Astragalus membranaceus grading.Therefore,exploring the regulatory mechanism of auxin and strigolactone on roots development of Astragalus membranaceus has a good application prospect.In this experiment,Astragalus membranaceus var.mongholicus(Bunge)P.K.Hsiao(A.mongholicus)and Astragalus membranaceus(Fisch.)(A.membranaceus)Bunge were used as the research objects,and different concentrations of IAA and GR24 were used to sock seeds,soak buds,and spray leaves.The effects of different treatment on roots length,lateral roots number and fresh weight of A.mongholicus were compared;the appropriate concentration of IAA and GR24 were selected to be indirectly sprayed on the leaves and directly added to the roots.The effects of the two hormones on the morphological indicators,endogenous hormones,and Expression of auxin-related and strigolactone-related genes of A.mongholicus and A.membranaceus roots;10% PEG6000 was used to simulate drought stress,and the changes of roots morphology index and physiological index of the control and drought group after different hormone treatments were compared.This study analyzes the effects of IAA and GR24 on roots growth and development of A.membranaceus seedlings under different treatments,and is of great significance for exploring the regulatory mechanism of its development.The research results are as follows:1.It shows that different treatment and different concentrations have certain effects on the growth and development of A.mongholicus roots,among which the effect of spraying leaves is more obvious.Spraying leaves of 1,5 ?mol/L IAA and GR24 has significant effects on the elongation of the main root and the number of lateral roots enhancement.2.Selecting IAA and GR24 to spray the leaves,the mixed treatment of two hormones has stronger promotion effect on main root elongation and lateral roots development than single treatment.This indicates that the two hormones play a positive role in regulating the development of root of A.mongholicus and A.membranaceus through the regulation of the expression of related genes.3.The addition of IAA and GR24 shows that IAA and the mixed treatment of both inhibit the elongation of the main root,and promote the development of lateral roots.On the contrary,GR24 may promote main root elongation by inhibiting auxin transporter.These results indicate that SL and auxin have an effect on the development of root of A.mongholicus and A.membranaceus through the interaction regulation mechanism.4.Using 10% PEG6000 to simulate drought stress,it showed that the growth and development of A.membranaceus after drought treatment was obviously delayed,the main root length was obviously increased,and the relative water content of the leaves was reduced.In general,exogenous hormones IAA and GR24 have certain effects on root morphology and physiological characteristics of A.membranaceus seedlings under drought stress.In conclusion,this study found that auxin and strigolactone affect the morphological indicators,endogenous hormone content,and related gene expression and regulation of A.mongholicus and A.membranaceus roots through different hormone treatments,and these two hormones and other plant hormones participate in the network regulation of the growth and development of A.mongholicus and A.membranaceus roots.