不同密度对杉木林根际土壤丛枝菌根真菌群落结构及共生格局的影响特征1

[Objective]Cunninghamia lanceolata is the widely planted timber species in China.To elucidate the characteristics of rhizosphere soil microorganism of C.lanceolata is helpful for scientific thinning and tending of C.lanceolata plantation.To clarify the response characteristics of Arbuscular Mycorrhizal Fungi(AMF)in rhizosphere soil of C.lanceolata plantations to density change,and the relationship and mechanism of action with understory vegetation diversity.[Methods]Based on High-throughput Illumina MiSeq sequencing,the diversity,structure,and symbiotic patterns of AMF communities in rhizosphere soil of C.lanceolata with different densities were assessed.[Results]A total of 163 AMF-OTUs were obtained from rhizosphere soils of C.lanceolata forest with densities of 1950/hm2、2250/hm2、2700/hm2、and 3300/hm2,belonging to 28 species,8 genera,6 families 5 orders 1 phylum,1 class.The α diversity index showed that the Chao1 and Shannon indices of AMF community decreased with the increasing of C.lanceolata stand density,but the difference was not significant.The β diversity index indicated that AMF community composition differed significantly among different densities of C.lanceolata.Bray-curtis dissimilarity analysis showed that 20 AMF community samples were clustered into two groups,corresponding to high density and medium-low density.Collinearity network analysis revealed a non-random pattern of AMF fungal composition.Glomus-mo-g23-vtx00222,Glomus-viscosum-VTX00063 and Glomus-Glo7-VTX00214 were identified as the key molecular species in the symbiotic network.A significant positive correlation was observed between the Shannon diversity index of the understory vegetation and that of rhizosphere soil AMF community.Redundancy analysis showed that soil alkali-hydrolysable nitrogen AN(NH4+-N)jointly affected the AMF community structure.[Conclusion]The density of C.lanceolata stand significantly affected rhizosphere soil AMF community structure.The main soil environmental factors affecting AMF characteristics were alkali-hydrolysable nitrogen and ammonium nitrogen,with a network centrality coefficient of 0.9434 in the symbiotic network.In the process of stand density change,Potential interactions between soil physicochemical properties and taxonomic groups may jointly influence the AMF community structure of C.lanceolata forest.The stand density affected soil microbial community,and the changed soil microbial community in turn aboveground vegetation.Finally,soil community and aboveground vegetation respond to density change cooperatively.This result provides new insights into the construction of ecological networks in which AMF mediates the above-and below-ground synergy of plants.