Association Of AM Fungal Diversity With Soil Properties And Plant Functional Traits In Karst Soil

The fragile ecological environment in karst area seriously restricts the development of regional economy and threatens the security of ecological system.The complex and changeable microtopography in karst area is easy to form a variety of niches,and the light and temperature The uneven distribution of soil water and nutrients in the niches leads to the heterogeneity of karst niches.Habitat heterogeneity may have an effect on the composition,structure and distribution of soil microbial communities,which are extremely sensitive to changes in environmental factors Arbuscular mycorrhizal fungi(AMF)are a kind of soil microorganisms with potential utilization value for the restoration of karst ecosystems.Fully understanding the distribution and diversity characteristics of AMF in the heterogeneous habitats of karst areas can provide a theoretical basis for the protection and restoration of degraded karst ecosystems by AMF At present,studies on AMF in karst areas mainly focus on the effects of AMF on photosynthetic physiological nitrogen and phosphorus absorption of plants in karst habitats and on the drought resistance of host plants.A few scholars have studied AMF diversity based on morphological identification and genetics.However,studies on the diversity characteristics of AMF community composition and its influencing factors in heterogeneous habitats have not been reported It is difficult for these studies to clarify the variation characteristics of AMF community and the related factors affecting the composition and diversity of AMF community in heterogeneous habitats in karst areas.Therefore,in this study,the AMF community in the karst habitat are taken as the research object,and the composition and diversity of the AMF community in the sample site were studied by high-throughput sequencing,and the habitat heterogeneity index of each sample site was measured and calculated The correlation analysis of soil properties and woody plant leaf functional traits are carried out by statistical methods to explore the changes of AMF community composition and diversity in karst habitats,and the relationship between habitat heterogeneity soil properties and leaf functional traits and AMF community composition and diversity.The results are as follows:(1)The AMF identified by high-throughput sequencing and cluster analysis belong to 4orders,7 families and 7 genera.Glomus was the dominant genus of soil AMF community in karst heterogeneous habitats,and its relative abundance was 88.77%;Diversispora(5.71%)>Scutellospora(2.04%)> Acaulospora(1.58%)> Paraglomus(1.54%)> Ambispora(0.26%)>Archaeospora(0.1%);the species composition and Alpha diversity(Shannon,Simpson,Ace and Chao index)of soil AMF community were significantly different from each other.(2)In karst areas,there were significant correlation between habitat heterogeneity and soil AMF community composition and diversity.The heterogeneity index and niche fraction were significantly correlated with the species composition of AMF community at different classification levels;soil AMF community diversity decreased with the increase of habitat heterogeneity,and the correlation was significant;there was a significant positive correlation between the AMF community diversity and the ratio of niche components in cracks,but no significant correlation between the AMF community diversity and other niche components.(3)In the karst habitat,the functional traits of woody plant leaves were correlated with the composition and diversity of soil AMF community.Leaf P content、LA、SLA、L/W、LDMC、leaf C/P、N/P ratios showed significant correlation between AMF community species composition,and there were different correlations between characters and AMF species;the AMF community diversity(Shannon、Simpson、Ace and Chao index)decreased with the increase of SLA、leaf C/P、N/P ratio,and increased with the increase of LDMC,and the correlation were significant.(4)In the karst habitat,Soil physicochemical properties were correlated with AMF community composition and diversity to varying degrees.Among them,Soil p H、TN、AP、AN、C/P、N/P、SOC and SOM were significantly correlated with AMF community species composition,and different correlations between soil factors and different species of AMF community,indicating that there were differences in the suitable soil environment for species of AMF community;the AMF community diversity increased with the increase of soil p H、TN、AN、AP、SOC and SOM content,and the correlation was significant.In conclusion,there were abundant AM fungi resources in heterogeneous habitats in karst areas,and there were significant differences in AMF community composition and diversity among different habitats;the habitat heterogeneity was significantly correlated with the species composition of AMF community at different taxonomic levels,the AMF community diversity decreased with the increase of habitat heterogeneity;the functional traits of woody plant leaves,including SLA、C/P、N/P ratio were significantly correlated with the composition and diversity of soil AMF community;soil factors including p H、TN、AN、AP、SOC and SOM significantly affected the composition and diversity of AMF community.