Study On Nutrition Absorption Characterstics Andfertilization Effect Model Of Astragalusmongolicus

Astragalus mongholicus is the dried roots of leguminous plant Astragalus membranaceus(Fisch.)Bge.Var.mongholicus(Bge.)Hsiao and one of the traditional bulk medicinal materials.The scientific fertilization technique is one of the main management techniques that affect the quality and yield of Astragalus mongholicus.In this thesis,Astragalus mongholicus was used as the research object,ITS2 sequence was used to identify Astragalus mongholicus and its counterfeit products in different regions,and the five-level secondary saturation-D optimal regression design of three factors of nitrogen,phosphorus and potassium was used.The growth characteristics and nutritional characteristics of Astragalus mongholicus during its growth period and its overall quality evaluation.Finally,the optimal fertilization amount was obtained through the establishment of a model and optimization,which provided a theoretical basis for the standardized cultivation technology of high quality and high yield of Astragalus mongholicus.The main results are as follows:(1)The ITS2 sequence of DNA barcode technology was used to identify Astragalus mand its adulterants,and each variety was clustered into a cluster on Neighbor-Joining tree,which indicated that ITS2 sequence could distinguish Astragalus mongholicus from Astragalus complanatus,Glycyrrhiza pallidiflora,Caragana sinica,Althaea rosea,Medicago sativa and other adulterants,in order to achieve the purpose of identification.(2)Fertilization had no significant effect on the root length of Astragalus mongholicus in different growth periods,but it could obviously promote the growth and development of plant height.From July to August,the chlorophyll content in the leaves of Astragalus mongholicus was higher,the photosynthesis was stronger.The polysaccharides content in the roots of Astragalus mongholicus reached a higher level in September,and polysaccharides could be extracted at the end of September.The accumulation of total flavone of Astragalus mongholicus reached its peak in November,and the contents of astragaloside IV and mullein isoflavone glucoside were the highest in the treatment of N0P2K2,but the yield was higher in the treatment of nitrogen,phosphorus and potassium.The accumulation of secondary metabolites was negatively correlated with plant biomass.(3)There were significant differences in the distribution of N-P,N-K and P-K elements in different organs of Astragalus mongholicus.The growth of Astragalus mongholicus under different fertilization treatments was restricted by N elements from June to November.There was no allometric relationship among N-P,N-K and P-K elements in the roots of Astragalus mongholicus under different fertilization treatments.The N-P elements in the stem showed an obvious allometric relationship,and there was a significant positive correlation between N and P elements,indicating that the absorption of N and P elements in the stems were mutually promoted.The proportion of N-K and P-K elements in the leaves showed positive correlation,indicating that the leaves can promote the absorption of K elements in the soil by the root system,and transport the nutrients to the leaves through the stems.(4)The principal component analysis between fertilization and quality indexes of Astragalus mongholicus showed the total contribution rate of four principal components was 85.176%,indicating that soil enzyme activity,microbial biomass,total flavone,and polysaccharides had a certain contribution in fertilization and quality evaluation.The first principal component results showed that urease,sucrase and phosphatase activities were superior in fertilization and quality evaluation;the second principal component results showed that the microbial biomass had a certain performance in fertilization and quality evaluation;the third and fourth principal component results showed that total flavone and polysaccharides were excellent in fertilization and quality evaluation of effective components.(5)Through the model establishment and optimization of the fertilization effect equation for Astragalus mongholicus yield and quality,the final determination was as follows:when Astragalus mwas applied with nitrogen(N)70.332～125.194 kg,phosphorus(P2O5)148.225～206.159 kg,potassium(K2O)87.019～166.269 kg per hectare,it was expected to achieve a yield of more than 4500 kg/hm2.;when Astragalus mongholicus was applied with nitrogen(N)8.393～51.840 kg,phosphorus(P2O5)12.537～77.438 kg,potassium(K2O)74.088～90.583 kg per hectare,it was expected to achieve higher than 0.28%astragaloside IV medicinal materials;when Astragalus mongholicus was applied with 36.098～119.839 kg of nitrogen(N),84.126～157.672 kg of phosphorus(P2O5),90.029～141.698 kg of potassium(K2O)per hectare,it was expected to obtain more than 0.035%mullein isoflavone glucoside medicinal materials.This could provide relevant agronomic guidance as needed.