Soil Characteristics Analysis And Identification Of Phenolic Acids Under The Continuous Cropping Obstacle Of Chinese Fir Superior Clones

Chinese fir is one of the most important fast-growing timber species in South of China.For a long time,it has been proved that the continuous planting of Chinese fir would result in the decline of soil fertility,which affects the long-term productivity of Chinese fir plantation and the sustainable management of forest land.Therefore,how to solve the problem of declining soil fertility caused by the continuous planting of Chinese fir and achieving the sustainable management of the continuous planting of Chinese fir has become the urgent technical problem to be solved.This paper adopted the method of indoor simulation of biological culture,the excellent clones of Chinese fir were screened by the research group.First-generation Chinese fir plantation(FC)soil?second-generation Chinese fir plantation(SC)soil?third-generation plantation(TC)soil were used as medium,after 2 years of respectively training.This paper used high-throughput sequencing analysis of the differences between the rhizosphere soil and non rhizosphere soil of Chinese fir clones.Meanwhlie this paper analysed chemical properties,soil microbial carbon and nitrogen,soil enzyme activity,soil microbial community structure,soil characteristics,and further application of LC-MS material identification methods and iTRAQ technology analysis and identification of Chinese fir clonal root and rhizosphere soil phenolic acids and differences related to phenolic acids metabolism protein.The results expounded on the response mechanism of the continuous planting of Chinese fir clones from soil science,metabolomics and proteomics point of view,which providing more detailed information for theory of the formation mechanism of planted Chinese fir barriers.The main results are as follows:(1)In the continuous cropping obstacle of Chinese fir clones about rhizosphere and non rhizosphere soil,the total K,total P,available K,total C content showed a larger value in SC.The effective P content increased with continuous plantation increasing,the reserved trend variation of rhizosphere and non rhizosphere soil in total N content.Available K,available P,total C reached significant difference level(P<0.05).In the same type of soil,the nutrient content of rhizosphere and non rhizosphere soil showed that rhizosphere was higher than that of non rhizosphere soil.The level of nutrients was significantly different basically.(2)In the rhizosphere soil and non rhizosphere soil of Chinese fir clones,urease,sucrase,catalase and acid phosphatase decreased with the increase of continuous cropping.It was basic differences between TC and others.In the same forest type soil of FC and SC,it showed that rhizosphere was greater than non rhizosphere in the soil enzyme activities.In continuous cropping of TC,mostly non rhizosphere soil enzyme activities are stronger.There were significant differences in the activities of the four enzymes except invertase.Analysis of soil chemical properties and enzyme activities showed that the total K and available K were positively correlated with polyphenol oxidase;effective P showed a significant positive correlation with invertase,was negatively correlated with catalase.The total C showed significantly positive correlation with urease and catalase.(3)In the successive planting of Chinese fir clones of the rhizosphere soil,MBC,MBN,MBC/MBN were smaller in the TC,while in the non rhizosphere soil,the index is even larger in the TC;In the same stand soil,most of the indexes showed that the rhizosphere soil was larger than the non rhizosphere soil;and the MBC and MBC/MBN index reached the level of significant difference.(4)In continuous planting of Chinese fir clones soil barrier,44 groups were identified in the level of bacteria category.The relative abundance of the top 5 types was Acidobacteria,Proteobacteria,Actinobacteria,Chloroflexi and Planctomycetes.Analysis of bacterial diversity showed that bacterial community diversity decreased gradually with the continuous plantation increasing in the rhizosphere,while in non rhizosphere soil,bacterial diversity of TC showed the strongest.In the same soil under Chinese fir forest types,rhizosphere was higher than non rhizosphere in bacterial community diversity of FC and SC.The analysis of RDA on the level of soil bacterial taxonomy indicated that the three environmental factors of effective P,MBC and available K were significantly or significantly correlated with the diversity of bacteria structure(P<0.05).(5)In continuous planting of Chinese fir clones soil obstacle,5 groups was identified in the level of fungal classification.Species which was more than 1%had Ascomycota,Basidiomycota and Glomeromycota.In the analysis of fungal community diversity,rhizosphere and non rhizosphere soil of SC reached abundant community structure.In the same forest types,community structure diversity of SC and TC showed rhizosphere was higher than non rhizosphere.The analysis of RDA in the taxonomic level of soil fungi showed that the available K and total P were correlated with the structural diversity of fungi significantly(P<0.01).(6)8 kinds of phenolic compounds were identified in successive planting of Chinese fir clones root tips.It had relatively higher content about catechins,quinic acid and kaempferol.The analysis about the root tips of phenolic acids and soil chemical properties correlation,soil enzyme activity and soil microbial community correlation showed that quinic acid relative content was negatively correlated with acid phosphatase;kaempferol which was negatively correlated with planctomycetes content was positively significant correlated with invertase.(7)11 kinds of phenolic acids were identified in the rhizosphere soil of Chinese fir clones,in which the contents of ferulic acid,gallic acid and caffeic acid were higher in the soil of the four stand types.From the analysis about rhizosphere of phenolic acids in soil and soil chemical properties,soil enzyme activity and soil microbial community correlation showed that the relative content of caffeic acid which was significantly negatively correlated with Acidobacteria had significantly positive correlation with the Chloroflexi;the relative content of ferulic acid which was extremely significant negative correlation with Chloroflexi was positively correlated with Acidobacteria;Gallic acid relative content was negatively correlated with total C and extremely negatively correlated with urease.(8)In the identification about the root tip protein of Chinese fir clones,the number of proteins and the number of proteins in the molecular mass range showed the FC was major.After predicting the function of protein,the function of post-translational modification?protein turnover and chaperone were found through compared with the COG database.The number of expressed differential proteins in different successive generations of Chinese fir root existed difference.Compared with the FC,the SC had respectively 141 differential proteins which were 77 up-regulated proteins and 64 down-regulated proteins;the TC had respectively 210 differential proteins which were 102 up-regulated proteins and 108 down-regulated proteins;The SC and TC had 77 up-regulated proteins and 91 down-regulated proteins.In the different successive generations of Chinese fir root proteins,there were 5 with the phenol acid synthesis related protein.The analysis about differential protein GO enrichment showed that,in the comparison of the differences between the three groups about the root tip of Chinese fir,the cell process,metabolic process and single biological process were mainly enriched in the biological process;cell components and organelles in the cell component entry;the catalytic activity and binding function in the molecular function entry.The difference of Pathway protein enrichment showed that the significant metabolic pathway had 8 in three stands.Among them,biosynthesis pathway of phenolic acids was related to the phenylalanine,tyrosine and tryptophan pathway.3 differential proteins were found.