| Ectomycorrhiza(ECM)is a reciprocal symbiosis formed by specific fungi and plant roots.The diversity of ectomycorrhiza fungi is an important factor to maintain the structural and functional diversity of ecosystem.Pinus massoniana Lamb.is a native tree species widely distributed in southern my country,and it is also a typical ectomycorrhizal fungus tree species.It plays an important role in afforestation and forest ecological economy.This study aimed at ectomycorrhizal fungi community composition and mechanism is important scientific problems associated tree species diversity,Guizhou typical pinus massoniana association as the object.Using the research methods of morphology and molecular biology,explore the community composition and diversity distribution characteristics of ectomycorrhizal fungi in the typical pinus massoniana association habitat explore vary with tree species richness ectomycorrhizal fungi alpha diversity and community composition change,and their influence ectomycorrhizal fungi community composition and structure of the main environmental driving factors.The main findings are as follows:(1)There were significant differences in plant community composition,diversity and soil physical and chemical properties among different Pinus massoniana association.A total of 120species of vascular plants,belonging to 62 families and 99 genus,were recorded.Among them,there are 22 species of trees,65 species of shrubs and 52 species of herbs.Plant community of dominant species of Pinus massoniana,Cunninghamia lanceolata,Quercus americana,Poplar alba,mountain pepper,ji fern,dicranopteris dichotoma,cold berries,such as species,including associationⅣ(pinus massoniana-liquidambar)the highest plant diversity,to build a single group of kind of the association of plant diversity is slightly lower than mixed type of association.The soil p H of each group is less than 7,and it is acidic or extremely acidic soil.Soil nutrient surface soil is higher than the lower soil presents on the whole,the layers of soil nutrients in associationⅣhighest.Soil temperature,p H,electrical conductivity,organic matter and plant community diversity index were significantly correlated(p<0.05).(2)Morphological diversity of ectomycorrhizal fungi in pinus massoniana communities in Guizhou Province is rich,mainly showing bifurcate,antler and coral-like branches;The main colors are white,yellow,black and intermediate colors.Mycelia are present or absent,showing filamentous,linear and curved shape.The mycorrhizal infection rate ranged from 89.76 to 97.95%.The results of molecular identification showed that 60 species of ectomycorrhizal fungi,belonging to 2 phyla,6 classes,15 orders,20 families and 21 genera,were symbiotic with pinus massoniana in different clusters.Among them,112 effective sequence belong to 1 class,7 orders,8 families and 8 genera,with a relative abundance of 53.33%.There are 98 effective sequence in Ascomycota,with a relative abundance of 46.66%,belonging to 5 classes,8 orders,12 families and 12 genera.The dominant groups were unclassified Helotiales,Russula,Latarius.The community composition and diversity of ectomycorrhizal fungi were significantly different in each cluster environment.(3)A total of 35 ectomycorrhizal fungi Quercus fabri、Populus adenopoda were obtained,belonging to 2 phyla,9 classes,19 families,25 genera and 63 species.Among them 28 ECM fungi associated with Quercus Americana belonged to 15 genus.The dominant species was Sebacina sp.There were 29 ECM species belonging to 13 genera,and the dominant groups were Cenococcum geophilum,Lactarius sp.and Tomentella sp3.The community composition and diversity of ectomycorrhizal fungi were different in different hosts.(4)Under the forested land of pinus massoniana group pinus massoniana and total seed(Quercus fabri,Populus adenopoda)ECM fungi community comprehensive analysis results show that under the forested land of pinus massoniana group ECM fungi have relatively abundant species diversity characteristics,detected the ECM fungi under different group of forested land 34 genera and 80 species,including unclassified Helotiales,Russula,Lactarius,Tomentella dominant position,is also in the study area pinus massoniana association among all.There were 15 genera endemic to each community,accounting for 83.33%of the total.46 endemic species,accounting for 97.87%of the total.In the community,there were more widely distributed species but fewer species,while fewer endemic species and more species.The Shannon-Wiener diversity index,Simpson index and Pielou evenness index of ECM fungi in different pinus massoniana association were different.(5)Through regression fitting analysis,the fitting regression equation of Shannon(Vegetation H)index of pinus massoniana association and Shannon(ECM H)index of ECM fungal community was y=1.481x~2-3.8188x+4.3895(R~2=0.6257).The fitting regression equation of Simpson(Vegetation H’)index and ECM fungal Simpson(ECM H’)index was y=0.7637x~2-0.9648x+1.1645(R~2=0.3563).The fitting regression equation of Pielou(Vegetation J)index of plant community and Pielou(ECMF J)index of ECM fungal community was as follows:y=-0.7578x~2+0.8891x+0.7002(R~2=0.3333).The results of canonical correspondence analysis showed that soil bulk density was the limiting factor of ectomycorrhizal fungi community composition and diversity under different pinus massoniana association.In summary,this study reveals the community structure and diversity of ectomycorrhizal fungi in different Pinus massoniana association in Guizhou,and the influence of host composition on the community of ectomycorrhizal fungi in Pinus massoniana forests in Guizhou,which provides scientific basis for further revealing the relationship between tree species diversity and underground mycorrhizal diversity,and provides scientific and technological support for formulating the management strategy of improving the ecosystem function of artificial forests in this region through reasonable combination and control of tree species richness. |
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