Study On The Nutrient Absorption Characteristics And Secondary Metabolism Regulation Of Astragalus Membranaceus (Fisch.) Bge

Astragalus membranaceus (Fisch.) Bge.is a plant of the family leguminous and aperennial herb.Its roots usually used as a traditional staple medicinal material.As ceaselessresearches in the rule of pharmacology and health care ofAstragalus membranaceus (Fisch.)Bge.,it is not only applied as medicinal materials but as materials in many industrialproduction such as beverage,invigorant,cosmetic and tea.The market demand of Astragalusmembranaceus (Fisch.) Bge.is increase with years.Accordingly,the cultivation Astragalusmembranaceus (Fisch.) Bge.is the primary source of medicinal materials.However the yieldand quality is lower than wilding Astragalus membranaceus (Fisch.) Bge.Because there isshort of the basic research in mineral nutrition and the information of fertilization inAstragalus membranaceus (Fisch.) Bge.is unsystematic.In this thesis,Astragalusmembranaceus (Fisch.) Bge.Was taken as experimental materials,the growing rules andnutrient absorption characteristics were explored by field experiments and chemical analysis.The accumulation dynamic of polysaccharide and total saponin in different fertilization leverand the optimization fertilization model for its growth,high-yield and good-quality wasascertained by three factor guadratic D-saturation optimization design in field experiment.The growth rule and secondary metabolism of hair root ofAstragalus membranaceus (Fisch.)Bge.was explored.These results not only have theoretical significance for plant nutrition andplant physiology but have important significance in planting technology of Astragalusmembranaceus (Fisch.) Bge.It will be beneficial to protecting natural resource of Astragalusmembranaceus (Fisch.) Bge.and to alleviating ecological environmental disruption.Theresults are also having great significance for modernization and internationalization ofModernization of Traditional Chinese Medicine.The main results were summarized asfollows:1.The accumulative law of dry matter was researched using the field experiment.Thedry matter accumulative curve could be described with Logistic equation and was"S"shape.The Logistic equation is W_t=(33170/1+298169e^-0.1087x).The distribution rates of dry matter of itsorgans changed greatly during its growth period.The most rapid period of dry matteraccumulation in shoots is between 100 to 132 days after the seedlings emergence but is between 163 to 185 days in root.2.Absorbing capacity and accumulative law of nutrient elements was systematicallystudied by the field experiment,chemical analysis and biological statistic methods.the resultsshow that absorbing capacity of nitrogen(N),phosphorus(P),potassium(K) in plant was insequence of N＞K＞P In its full-growing stage.The nutrient absorption amount of N,P,and Kin shoots is much than in root.Content of iron(Fe),manganese(Mn),zinc(Zn),copper(Cu) inroot was in sequence of Fe＞Zn＞Cu＞Mn but in plant it was Fe＞Zn＞Mn＞Cu。N,P,K accumulation increased continuously and reaches the peak amount at the days of163d after seedlings emergence then it returned to a slow increase until harvest.Accumulationof N,P,and K in root is increase all along and reached its maximum at harvest time.Accumulation of N in plant is the largest,next is K accumulation and P accumulation is thethird.Using the concept of relative accumulation rate,the nutrient critical period and thehighest efficiency period was ascertained.Nutrient critical period of N,P,and K is in the daytime of 70-100d after the seedlings emergence and the highest efficiency period is in the dayof 100-132 d after the seedlings emergence.In its full-growing stage,the amount of nutrientaccumulation in roots was in sequence of N＞K＞P＞Fe＞Zn＞Mn＞Cu.The nutrient requirementfor 100kg roots of Astragalus membranaceus (Fisch.) Bge.was 2.32kgN;0.323kg P₂O₅;1.62kg K₂O;37.77gFe;2.24g Zn;0.66g Mn and 0.65gCu.If compared with N,P,and Knutrients by proportion,the formula is as follows:N:P₂O₅:K₂O=7.18:1:5.02.3.The results of field experiment that using three factor D-saturation optimization designshow that the growth,yield and secondary metabolism were strongly impacted by rate of N,P,K fertilizer.The influence degree of N,P,K for yield was in order of N＞K＞P,forpolysaccharide accumulation was K＞P＞N,for flavonoids accumulation was K＞N＞P.According to frequency analysis and through simulated optimization,optimum fertilizerapplication scheme was N138-156Kg/ha,P₂O₅79-85 Kg/ha,K₂O122-143 Kg/ha in targetyield of root yield is 6300-7300 kg/ha and target content of total saponins is 12.0-13.5 mg/g.The nutrients proportion of N,P,K is as follows:N:P₂O₅:K₂O=1:0.5:0.87.4.Culture system of hair root of Astragalus membranaceus (Fisch.) Bge.withAgrobacterium rhizogene R1601 was established.The results indicated that transformationfrequency on hypocotyl explants was higher than that on the explants of leaf,stems andcotyledon.Hairy roots could come out 3-4 d earlier than usual treatment if explants wereprecultivated for 3 d.The best infection time was 15 minutes and the best bacteria remover iscarbenicilin.The results showed that the growth period of hair root can be divided intodelayed phase(0-5 d),constant speed growth phase(5-25 d) and decline phase(25-40 d).Thegrowth amount of hairy root up to the maximum value after 25 days of culture.The growth rate of dry weight in constant speed growth phase could be described with follow equation:(dx/dt)=(3.37g/F.d) R²=0.841**The growth of hairy root and biosynthesis of polysaccharide and total saponins werewere promoted by IAA and NAA.The growth of hairy root and biosynthesis ofpolysaccharide and total saponins were restrained by 2,4-D.IBA promoted the growth butinhibited the biosynthesis of polysaccharide and total saponins of hairy root.Methyljasmonate and Salicylic Acid could stimulate the growth and accumulation of polysaccharideand total saponins in hair root ofAstragalus membranaceus (Fisch.) Bge.