| Wild-simulated Astragali Radix from Hunyuan has an excellent quality.Suitable ecological environment is the basis for the excellent quality of Wild-simulated Astragali Radix from Hunyuan.The accumulation of effective components of Chinese herbs is easily influenced by the community structure of companion plants.However,there is no report on the analysis of the ecological adaptation of Wild-simulated Astragalus membranaceus(Fisch.)Bge.var.mongholicus(Bge.)Hsiao from Hunyuan(WAMH)from the perspective of companion plants.Therefore,we first investigated the community structure of the companion plants of WAMH.Second,the soil physicochemical properties were determined and the correlation between soil physicochemical properties and companion plants were analyzed.Third,high-throughput sequencing technology was used to study the rhizosphere soil bacterial community structure and to analyze the correlation between the companion plants of WAMH and soil bacteria(genus level).Finally,the effective components of WAMH were measured,the correlation between soil physicochemical properties and active ingredients,and correlation between soil bacteria and the active ingredients were analyzed.The soil physicochemical properties and soil bacteria were significantly correlated with the companion plants of WAMH.The study contents and results are as follows:1 Survey and analysis of companion plant communities of WAMHThe investigation results of the family,genus and species composition of the companion plant community of WAMH showed that the companion plants of WAMH were dominated by single species family and single genus,and the community structure were complex.From the results of the importance value calculation,it could be seen that the companion plants with higher importance values on shady slopes were Duchesnea indica,Thalictrum przewalskii,Aster subulatus,etc.The companion plants with higher importance values on the sunny slopes were Medicago sativa,Potentilla chinensis and Brassica juncea var.napiformis.From the results of the diversity index calculation,it could be seen that the all diversity indexes of the companion plants on shady slopes at high altitude were the highest,indicating that the ecological environment on shady slopes high altitude was the most stable place.The results of the niche width calculation showed that the companion plants with larger niche width on the shady slope were T.przewalskii,Polygonum aviculare,A.subulatus,etc.The companion plants with the largest niche width on the sunny slope were M.sativa,B.juncea var.napiformis,P.chinensis,etc.From the results of the overlap niche calculation,we could see that the niche overlap values of high altitude companion plants on shady slopes were greater than 0.1 and less than 0.5,indicating that high altitude companion plants on shady slopes shared the highest degree of local resources and could make full use of resources without competition.2.Determination of soil physicochemical properties and correlation analysis between soil physicochemical properties and companion plantsThe soil physicochemical properties of WAMH were determined.The analysis showed that there was no significant difference in soil p H at the four sampling sites.Soil bulk density and soil water content were significantly(P<0.05)higher at low altitude than at high altitude.Available potassium,total nitrogen and total phosphorus were significantly(P<0.05)higher at high altitude in shady slopes than in other sample sites.The correlation analysis of soil physicochemical properties showed that the most critical factor affecting the soil physicochemical indexes was soil bulk density.The correlation analysis between the diversity of the companion plants of WAMH and soil physicochemical properties showed that Simpson index,Shannon-Wiener index,Pielou index and Alatalo index had highly significant(P<0.01)positive correlations with available potassium.Patrick index,Margalef index,Simpson index,Shannon-Wiener index,Pielou index and Alatalo index had highly significant(P<0.01)positive correlations with total nitrogen.The Alatalo index showed a highly significant(P<0.01)positive correlation with total phosphorus.The correlation between the importance values of WAMH companion plants and soil physicochemical properties showed that the importance values of Artemisia lavandulifolia and Artemisia annua were highly significantly(P<0.01)positively correlated with available potassium.The importance values of T.przewalskii,P.aviculare,etc.showed highly significant(P<0.01)positive correlations with total nitrogen.The importance values of B.juncea var.napiformis,Conyza canadensis,and Chrysanthemum chanetii showed highly significant(P<0.01)negative correlations with total nitrogen.The importance values of D.indica,A.lavandulifolia,etc.showed highly significant(P<0.01)positive correlations with total phosphorus.The results of correlation analysis between width of companion plants of WAMH and soil physicochemical properties showed that the niche widths of T.przewalskii,A.subulatus,etc.showed highly significant(P<0.01)positive correlations with total nitrogen.The niche width of D.indica was positively correlated with total phosphorus in a highly significant(P<0.01)correlation.3.Study structure of rhizosphere soil bacterial community of WAMH and correlation analysis between bacteria and companion plantsThe results of the diversity analysis showed that the ACE values of soil bacteria at low altitude on shady slopes were lower than the remaining three sample sites.The results of differential species in the rhizosphere soil of WAMH showed that Micrococcales order,Micrococcaceae family were the species with significant differences at low altitude on the shady slope;Xanthobacteraceae family was the species with significant difference at high altitude on the shady slope;there was no significantly different bacteria at high altitude on the sunny slope.Gemmatimonadetes,Gemmatimonadales,etc.were the species with significant differences at low altitude on the sunny slope.From the analysis results of rhizosphere soil bacterial community composition of WAMH,it could be seen that the phylum level ranked in the top 10 were Proteobacteria,Acidobacteria,Firmicutes,etc.The dominant bacteria in the top 20 genera were Atopostipes,Sporosarcina,RB41,etc.From the correlation analysis of companion plant diversity and soil bacteria,it was observed that the Margalef index,Simpson index,Shannon-Wiener index,and Alatalo index of companion plant diversity showed highly significant(P<0.01)positive correlations with Sphingomoas.The Pielou index was significantly(P<0.01)positively correlated with MND1,Ellin6067,Subgroup＿10,etc.The correlation analysis between the importance values of companion plants and soil bacteria showed that the companion plants with larger importance values were significantly positively correlated with Acinetobacter,Bradyrhizobium,and Sphingomonas.The correlation analysis of width of companion plants and soil bacteria showed that companion plants with larger ecological width were significantly positively correlated with Allorhizobium-Neorhizobium-ParararhizobiumRhizobium,Acinetobacter,Atopostipes and Bacillus.4.Determination of active components of WAMH and correlation analysis between active component and soil environment factorFirst,factor analysis of the 12 indicator components showed that the composite score of WAMH at high altitude on shady slopes was significantly(P<0.05)higher than other three sample sites.Secondly,according to the results of the analysis in Chapter 4,soil physicochemical properties,which were significantly(P<0.05)related to companion plants,were used as indicators to analyze the correlation between 12 active components of WAMH and these soil physicochemical properties indexes.The analysis showed that total nitrogen in the soil was significantly(P<0.05)positively correlated with Astragali Ⅰ and isomucronulatol-7-O-glucoside.Third,combining the analysis results in Chapter 5,Sphingomonas,Nitrospira,etc.,which were significantly(P<0.05)related to companion plants,were used as indicators to analyze the correlations between the active ingredients of WAMH and the above soil bacteria.The results showed a highly significant(P<0.01)positive correlation between Sphingomonas and Astragalus Ⅳ.AllorhizobiumNeorhizobium-Parararhizobium-Rhizobium and Acinetobacter showed highly significant(P<0.01)positive correlations with Astragaloside III.Haliangium showed a highly significant(P<0.01)negative correlation with Astragaloside I.Bradyrhizobium showed highly significant(P<0.01)positive correlations with isomucronulatol-7-O-glucoside and isomucronulatol.There was a highly significant(P<0.01)negative correlation between Mesorhizobium and Astragaloside Ⅳ.Finally,a comprehensive discussion concluded that it was possible that A.annua,M.sativa,etc.increased the total nitrogen content in the soil and promoted the accumulation of Astragaloside I and isomucronulatol-7-O-glucoside content.The relative abundances of soil beneficial bacteria such as Sphingomonas,Allorhizobium-Neorhizobium-Parararhizobium-Rhizobium,etc.were increased due to the roles of the companion plants such as P.aviculare,T.przewalskii,etc.The soil bacterial community structure was improved,which promoted the accumulation of active substances such as Astragaloside Ⅳ,Astragaloside III,isomucronulatol-7-O-glucoside,and isomucronulatol of WAMH.The research results can provide the necessary reference materials for the further study of ecological adaptability and reasons of superior quality formation of WAMH. |
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