Tissue Culture Of Astragalus Membranaceus (Fish.) Bge. Var. Mongholicus(Bge.) Hsiao And Effects Of N~+ Implantation On Its Biochemical Indexes

In this paper the inconsistency of the rapid increase in demand and sharp decrease in resources which could explain the change of root shape and reduction of medical composition of Astragalus membranaceus(Fish.) Bge.var.mongholicus(Bge.) Hsiao was firstly introduced,and then the significance and imminency of breeding Astragalus membranaceus(Fish.) Bge.var.mongholicus(Bge.) Hsiao with high quality was put forward.The research on tissues culture lays the groundwork for further mutation and polyploidy breeding in Astragalus membranaceus(Fish.) Bge.var.mongholicus(Bge.) Hsiao.In the experiments,tissues culture system for Astragalus membranaceus(Fish.) Bge.var.mongholicus(Bge.) Hsiao was established through screening out explants,culture media and other factors,then the contents of endogenous hormone in callus were measured,and finally the biochemical effects of N~+ implantation on Astragalus membranaceus(Fish.) Bge.var.mongholicus(Bge.) Hsiao leaves were studied,all of which provide experimental evidence for future mutation breeding in Astragalus membranaceus(Fish.) Bge.var.mongholicus(Bge.) Hsiao by ion beam implantation.The results showed that the leaves of Astragalus membranaceus(Fish.) Bge.var.mongholicus(Bge.) Hsiao were the optimum explants.The culture media of inducing callus, growth,adventitious shoots differentiation,and producing root were MS+2.0mg/L 2,4-D+1.0mg/L 6-BA+0.6mg/L NAA,MS+2.0mg/L 6-BA+0.5mg/L NAA,MS+2.0mg/L 6-BA+0.5mg/L NAA+1.0mg/L KT+0.2mg/L IBA,and 1/2MS+0.5mg/L NAA+1.0mg/L BAT,respectively.In the tissues culture system,induction rates of callus from leaves,and adventitious shoots and roots from callus were respectively 72.5%,15.7%and 65%.The measurement results of endogenous hormone in callus were showed that GA was the evocator of callus induction,IAA and ZR were important factors in growth of callus,and low content of ABA favored the formation of callus.In the fastigium of embryonic callus formation and differentiation phase of adventitious shoots,IAA and ABA contents decreased,ZR content increasesd,and GA content first increased and then decreased,which further illuminated that both high content of ZR and low contents of IAA and ABA might favor the inductions of embryonic callus and adventitious shoots.Tiny change in exogenous hormone could cause obvious alteration in endogenous hormone.In order to get embryonic callus with adventitious shoots,not only absolute contents of endogenous hormones,but also the ratios between them should be controlled in a certain range which is determined by contents and ratios of endogenous hormones in early adventitious shoots.The experiment also demonstrated that effects of different doses of N~+ implantation on the germination vigor,germination rate and survival seedling rate of Astragalus membranaceus(Fish.) Bge.var.mongholicus(Bge.) Hsiao seeds as well as on the chlorophyll content,activities of POD, CAT,and SOD,and content of MDA in the leaves of Astragalus membranaceus(Fish.) Bge.var.mongholicus(Bge.) Hsiao seedlings were obvious.The results showed that the germination vigor and rate of Astragalus membranaceus(Fish.) Bge.var.mongholicus(Bge.) Hsiao seeds showed the trend of declining-rising-declining with the increasing dose of N~+ implantation,which displayed a peculiar "saddle" shape.The survival seedling rate was close to germination rate at low dose,but significantly decreased at high dose.To consider the chlorophyll content,activities of POD,CAT, and SOD of the leaves,N~+ implantation was capable of stimulating effect at lower dose and inhibiting effect at higher dose.The content of MDA was lower than that of control at low dose,but increased with the increasing dose.SDS-PAGE analysis of protein in seedling leaves showed that different N~+ implantation dose caused different absence of protein bands in degree.Not only migrating rates of protein bands,but also molecular weights of proteins changed in different degrees.It can be concluded that low dose N~+ implantation in Astragalus membranaceus(Fish.) Bge.var.mongholicus(Bge.) Hsiao seeds could enhance the mutation rate,and thus may provide an efficient method for mutation breeding.