退化野果林表层土壤理化特性与微生物群落特征

Field: Agricultural and Biological Sciences (Life Sciences)

In the present study, soil microbial community was used as the object to investigatethe community structure and diversity characteristics and their under the degeneratedwild apple forest dominated by Malus sieversii in the wild fruit forest improvementstation of Xinyuan county , Xinjiang . The result showed that 1. Soil organic carbon(SOC), total nitrogen (TN), total phosphorus (TP )soil physical and chemicalproperties of the main indicators in the degenerated area and health range was notsignificantly different (P > 0.05). 2. By means of the coarse cultivation, actinomycetes,fungi number three groups at different distances from the trunk had no obviousregularity, but the numbers of three groups of microbes in degraded areas weresignificantly higher than that under alive trees crown (P < 0.05). By plate cultivationmethod, we found that the number of bacteria, actinomycetes and fungi exhibited noobvious regularity among different distances to the tree trunk. However, the numbersof bacteria, actinomycetes and fungi under dead wild apple trees crown were insignificantly higher than those under alive wild apple trees crown(P < 0.05). Theculture-dependent fungi can be divided into 3 phyla, 6 classes,8 orders,10 familiesand11 genera.The shared fungi genera were Penicillium, Fusarium, Aspergillus,Absidia, Nectria, Trichoderma, Metarhizium, the endemic genera under alive wildapple trees crown were Clonostachys, Purpureocillium and the endemic genera underdead wild apple trees crown were Leptosphaeria, Phoma.3. The soil harbored similarmicrobiota at the dominant taxonomic levels ( from phylum to genus). By the 16SrRNA gene sequencing and analysis, the soil bacterial microbiota can be divided into35 phyla, 104 classes,160 orders,199 families and 305 genera. At the phylum level，the microbiota were dominated by Actinobacteria, Proteobacteria, Crenarchaeota,Acidobacteria, Chloroflexi. The predominant families were Nitrososphaeraceae,Gaiellaceae, Hyphomicrobiaceae, Chitinophagaceae, Micromonosporaceae. At thegenus level, the microbiota were dominated by Candidatus Nitrososphaera,Rhodoplanes, Pseudonocardia. The tree dieback decreased the soil bacterialcommunity diversity（shannon and chao1 diversity index）but it showed no significant difference between alive wild apple trees crown and dead wild apple trees crown.4. By the ITS gene sequencing and analysis, the soil fungal microbiota can be dividedinto 6 phyla, 20 classes,79 orders,150 families and 361 genera. At the phylum level，the microbiota can be by Ascomycota, Basidiomycota , Zygomycota,Chytridiomycota , Rozellomycota, Glomeromycota and some unclassfied fungi. TheAscomycota was the dominant phylum with the relative abundance 77%-95%. Thepredominant families were Trichocomaceae , Herpotrichiellaceae , Nectriaceae,Lasiosphaeriaceae, Chaetomiaceae, Sporormiaceae. At the genus level, the fungicommunities were dominated by Penicillium, Exophiala, Mortierella, Fusarium,Ochroconis Trichocladium, Preussia, Podospora, Cyphellophora, Tetracladium. Thetree dieback decreased the soil fungal community diversity（shannon and chao1diversity index）but it showed no significant difference between alive wild apple treescrown and dead wild apple trees crown. 5. The degeneration of wild fruit forestdecreased the genetic diversity of topsoil microbiota. The microbial population oftopsoil under alive and dead apple trees crown showed a significant differentiation.6.The above study may indicate that a variety of aspects (soil nutrient, soil enzymeactivity, the number of cultivatable microorganisms, microbial community structureand diversity ) of the soil quality responded differently to the degeneration of the wildfruit forest. Compared to the soil physical and chemical properties, the soil microbiotaitself responded more sensitively to the degeneration of the wild fruit forest. When itcomes to the ecological restoration and conservation of the wild fruit forest in thefuture, it may not need to consider the soil nutrient status of itself in a short term. Itmay provide new thoughts for applying microbial agent to facilitate the ecologicalrestoration and conservation in the wild fruit forest.