| Lushan mountain is an important intersection of the ecological geographical distribution of species in the central region of China,which has a high ecological value and conservation significance.However,Lushan is also an "ecological island",with its ecological corridor cut off by the city and the road,which has become a biological sanctuary in the middle and lower reaches of the Yangtze river plain.Therefore,in order to fill in the blank of the study on the underground AM fungal community and its function in Lushan subtropical forest,this study takes the typical subtropical evergreen broad-leaved forest and evergreen deciduous broad-leaved mixed forest as the research object,and through morphological taxonomy identification,Research among the common tree species(Ulmus pumila,Ligustrum lucidum,Symplocos stellaris,Loropetalum chinense,Camellia fraterna,Lindera glauca,Lindera reflexa,Rhododendron simsii,Corylopsis sinensi)of the diversity and distribution characteristics of AM fungi community in rhizosphere soil were obtained as follows:(1)In this study,78 species of AM fungi in 12 genera were isolated and identified from rhizosphere of common plants in subtropical broadleaf forest and evergreen deciduous broadleaf mixed forest,including 5 the most common species,14 common species and 59 rare species,among which Glomus and Acaulospora were dominant genera.The spore density of AM fungi in rhizosphere soil of different tree species was not significantly different(p > 0.05),the community similarity was also high(Csmax: 75.56%),but the abundance was significantly different(p<0.05).The community diversity of rhizosphere AM fungi of different tree species was different from that of Pielou,among which Rhododendron simsii had the highest community diversity index(3.36),while Symplocos stellaris and Camellia fraterna had the highest community uniformity index(0.90).(2)The p H values of rhizosphere soil of different tree species were not significantly different(p>0.05),but the water content of rhizosphere soil and other nutrients(ammonium nitrogen,nitrate nitrogen,organic matter,etc.)were significantly different(p <0.05).According to the structural equation model,it was found that tree species directly affected the abundance of AM fungi,but also indirectly affected the abundance of AM fungi by affecting the total potassium in the soil.(3)The total abundance of AM fungi species in the rhizosphere of tree species on the south slope was higher than that on the North slope.There was no significant difference in the spore density of AM fungi in rhizosphere soil of the same tree with different slope directions(p>0.05),and there was no significant difference in the species abundance except Rhododendron simsii(p> 0.05).The diversity index of rhizosphere AM fungi in the south slope is higher than that in the North Slope.According to principal component analysis(PCA),slope direction explained 32.41 % of the species distribution of AM fungi,in which the communities of AM fungi in rhizosphere soils of different slopes of Lindera reflexa and Rhododendron simsii were quite different.By further redundancy analysis(RDA),it was found that soil nutrients and water in different slope directions had little influence on the distribution of AM fungi,which were explained by 19.01 %,19.22 % and15.70 % in Lindera reflexa,Rhododendron simsii and Corylopsis sinensi,respectively.(4)there were significant differences in the infection characteristics of AM fungi in different plant roots in Lushan subtropical broadleaf forest and evergreen deciduous broadleaf mixed fores(p < 0.05),which could be divided into 5 gradations.The total root infection rate of C.sinensis was the highest(45.80 %),while that of L.reflexa was the lowest(27.40 %).The influence of slope direction on the total infection rate of AM fungi in plant root systems was not significant(p > 0.05),but the infection rate of AM fungi in the root systems of L.reflexa and R.simsii on the southern slope of Lushan mountain was higher than that on the northern Slope,while the C.sinensis had the opposite characteristics.(5)Lushan subtropical broadleaf forest and evergreen deciduous broadleaf mixed forest has a high diversity of underground AM fungi,rich in resources,most rare species,and there may be indigenous AM fungi unique to lushan mountain.In terms of distribution,AM fungi are not evenly distributed,which are less affected by soil nutrients,but more affected by plants than soil nutrients and water,and are more affected by slope direction.Therefore,this research is not only beneficial to deepen the understanding of Lushan subtropical forests of AM fungi,Lushan subtropical forest soil,plants,and also can get the potential relationship between AM fungi,and plant diversity in Lushan mountain forest ecosystems to maintain and restore mechanism has theoretical significance,Lushan unique native AM fungi can also be used for the development and utilization of germplasm resources to provide theoretical reference. |
PDF Full Text Request