Secondary Metabolites And Rhizosphere Soil Characteristics Of Houttuynia Cordata Thunb.

Houttuynia cordata Thunb.,as a traditional medicinal plant in China,has played an important role in antipyretic,anti-inflammatory,antibacterial,anti-viral,enhance immunity,and so on,and been identified as one of the potential resources,which could be used as “both medicine and food” and be widely concerned.In recent years,the yield of wild H.cordata to meet the demand is difficult due to the continuous development of the medicinal,edible and health value of H.cordata,.H.cordata.has chosen artificially cultivated in more and more places.There are different at the cultivation techniques in different regions and climatic conditions.However,the reasons are poorly understood.Therefore,in this paper,H.cordata was used as the object,the affecting factors of the accumulation of secondary metabolites are explored via the relationship between the secondary metabolites of H.cordata and rhizosphere soil characteristics.This is a great significance for improving the quality and large-scale cultivation of H.cordata.Initially the experimental results obtained were following:1.Characteristics of the rhizosphere soil of H.cordataThe contents of organic matter,nitrogen,phosphorus and potassium,and the activities of invertase,urease and phosphatase in the rhizosphere soils of H.cordata from different sources were different.The urease activity in the rhizosphere soils of H.cordata was the highest,followed by the sucrase.Physical and chemical indicators of eleven rhizosphere soils of H.cordata from Pingzhai of Liping,Yangguitian of Guiyang and Fan Jingshan of Jiangkou were analyzed using factor analysis.The main factors resulting in the differences in the soil samples were organic matter,alkali nitrogen,p H and urease activity,followed by total nitrogen,available potassium and sucrase activity.There is a correlation between soil enzymes and soil nutrients.There was a significant positive correlation between invertase and total nitrogen and available potassium(P<0.01).Urease was significantly positively correlated with alkaline nitrogen and p H(P<0.01).Phosphatase was significantly positively correlated with total phosphorus and available phosphorus(P<0.01).Comparing the nutrients and distributions and contents of microbial communities rhizosphere soils of H.cordata shown that the species and distribution of soil microbial communities were related to the nutrient content.There was little effect of soil nutrients on soil microbial biomass and various microbial communities.The accumulation of some secondary metabolites of plants were certain affect by soil microbes,and the bacterial communities plays a major role.2.The accumulation of secondary metabolites of H.cordataThe content of secondary metabolites of H.cordata leaves from different sources were different,including phenols(Chlorogenic acid,afzelin,quercetin,rutin,quercitrin and isoquercitrin)and volatilies(Linalool,?-pinene,cis-3-hexenyl-acetate,hexanol,camphene,trans-2-hexen-1-ol,?-pinene,?-myrcene,bornylacetate,limonene,cineole,borneol,trans-2-hexenal,?-caryophyllene,2-undecanone,?-terpinene,cis-3-hexen-1-ol,decanal,decanol).The order of contents of phenolics from high to low was quercetin,afzelin,isoquercitrin,chlorogenic acid,rutin and quercetin.The contents of quercetin were between 570.88 to 2524.39 ?g/g,the contents of afzelin were between 143.03 to 1196.61 ?g/g,the contents of isoquercitrin were between 61.83 to 303.71 ?g/g,and the contents of chlorogenic acid were between 42.04 to 97.49 ?g/g,the contents of rutin were between 8.68 to 66.88 ?g/g,and the contents of quercetin were between 0.63 to 14.31 ?g/g.There were correlations between the contents of secondary metabolites of H.cordata.There was a significantly positive correlation between isoquercetin and rutin(P<0.01),and a significant positive correlation with afzelin(P<0.05).There was a significantly positive correlation between quercetin and rutin and afzelin(P<0.05),and a significantly positive correlation with isoquercitrin.There was a significantly negative correlation between limonene and isoquercitrin and quercetin(P<0.05).There was a significantly positive correlation between hexanol and quercetin(P<0.05).There was a significantly positive correlation between camphene and decanal(P<0.05),and a significantly positive correlation with bornyl acetate(P<0.01).3.Correlation between the secondary metabolites and the rhizosphere soil characteristics of H.cordataThere are correlations between secondary metabolites of H.cordata and the rhizosphere soil haracteristics.Isoquercitrin of H.cordata leaves was significantly negatively correlated with total nitrogen and available potassium(P<0.05).Rutin was significantly negatively correlated with the total nitrogen(P<0.01).?-pinene was significantly positively correlated with the total phosphorus(P <0.05).There was a significant positive correlation between ?-myrcene and p H(P<0.05).There was a significantly positive correlation between limonene and available potassium(P<0.01).?-Terpinene was significantly positively correlated with the organic matter(P<0.05).There was a significantly negative correlation between decanal and organic matter(P<0.01),significantly negative correlation with alkaline nitrogen(P<0.05).There was a significantly positive correlation between bornyl acetate and organic matter in soil(P<0.01).PLFAs of bacteria and soil microbes were significantly positively correlated with afzelin and quercetin(P<0.01),and positively correlated with quercitrin(P<0.05).There were significant positive correlation between fungal and quercetin and afzelin(P<0.05).soil microbes and bacteria were positively correlated with the trans-2-hexenal,cis-3-hexenel-acetate,hexanol,cis-3-Hexene-1-ol,trans-2-Hexene-1-ol and decanol(P<0.01),and a significantly positive correlation with ?-terpinene and ?-caryophyllene(P<0.05).