Relationship Between Secondary Metabolites And Soil Environmental Factors Of Houttuynia Cordata Thunb. During The Reproductive Period

Houttuynia cordata Thunb,as a traditional medicinal and food homologous plant,has also attracted much attention in recent years.The medicinal plant medicinal components are regulated by environmental factors.Although its wild resources are abundant,the medicinal effect of Chinese herbal medicines is often associated with "geoherbalism".Research on the interaction between the effective ingredients of herbal medicines and environmental factors is helpful to the development and utilization of its medicinal value.This article takes H.cordata as the research object,to reveal the environmental factors affecting the accumulation of secondary metabolic components of H.cordata,by analyzing the relationship between the phenolic and volatile components of H.cordata at the squaring stage,flowering stage and fruiting stage with soil physicochemical,soil enzymes and soil microorganisms,provide basic reference for H.cordata metabolomic research.The experimental results obtained are following:1.The distribution of phenolics and volatiles in H.cordata samples during the bud,flowering and fruiting periods mainly showed the law of leaf > above-ground stem > underground stem,and the distribution of phenolic and volatile contents in each sample showed significant differences.The accumulation of phenolics and volatiles in the fruiting period was higher than that in the squaring stage.2.To analyze the microbial characteristics of rhizosphere soil during the reproductive growth period of H.cordata.The results showed that 27 kinds of phospholipid fatty acids(PLFAs)were detected in the H.cordata rhizosphere soil during the reproductive growth period.There is no significant difference in the composition of the microbial community between the flowering stage and the fruiting stage.And in terms of total amount of PLFAs,the sequence of bacteria > fungi > actinomycetes >nematodes was found.The Shannon index of the soil microbialcommunity structures had the highest in Kaiyang 9 squaring stage-KY9(2.21),the lowest in Kaiyang10 squaring stage-KY10(1.65).The Pielou index was the highest in Kaiyang9 squaring stage-KY9(0.68),and the lowest in Kaiyang1 fruiting stage-XY1(0.53).The Simpson index was the highest in Xifeng squaring period-XF(0.85),and the lowest in Kaiyang1 fruiting period-KY1(0.69).The microbial structures of H.cordata rhizosphere soils changed to stabilize from flowering to fruiting periods,indicating that the change of the soil microbial structures was related to plant growth and participated in the regulation of H.cordata flowering period.3.To analyze the nutrients and enzyme activities of rhizosphere soil during the reproductive growth period of H.cordata.The results showed that there were significant differences in the nutrients and enzyme activities in H.cordata rhizosphere soils at different growth periods.The soil carbon to nitrogen ratio was significantly negatively correlated with phosphatase(p < 0.05),pH was significantly positively correlated with the invertase(p <0.05),and extremely significantly positively correlated with the urease(p < 0.01).The total phosphorous were significantly positively correlated with the invertase and urease(p < 0.05),and the alkali nitrogen and total nitrogen were significantly positively correlated with the urease and invertase(p <0.01).4.To analyze the correlation between the phenolic components of H.cordata(chlorogenic acid,rutin,quercetin,isoquercitrin,afzelin and quercetin)and the characteristics of rhizosphere soils.The accumulation of phenolic components of H.cordata in the bud stage,flowering stage and fruit stage were significantly different.The results of RDA analysis showed that the bacterial communities were the main factors affecting the accumulation of six phenolic components.The correlation of chlorogenic acid,rutin,quercetin,isoquercitrin,quercetin and afzelin were relativewith Shannon,Pielou and Simpson indexes of soil microorganisms,but not significant.5.Correlation between the H.cordata volatiles and the rhizosphere soil characteristics.It showed that the microbial community structures of H.cordata affected the reproductive growth of H.cordata.The available phosphorus was main factor affecting soil nutrients on volatile components,but the affecting level of the factor at every periods was different.There was a significant correlation between the soil microorganisms and volatiles of H.cordata.And linalool and methyl n-nonanone at flowering stage were positively correlated with the Shannon and Simpson indexes(p < 0.05),and extremely significantly positively correlated with the Pielou index(p < 0.01).3-tetradecanone was significantly positively correlated with the Shannon,Pielou,and Simpson indexes(p < 0.05).The eugenol at fruiting period was significantly positively correlated with Shannon index(p < 0.05).