Species Diversity Of AM Fungi In The Rhizosphere Of Six Shrub-grass Layer Plants In Fanjingshan National Nature Reserve

Arbuscular mycorrhiza(AM)fungi are extremely widely distributed in natural ecosystems,which can form a symbiotic relationship with more than 80% of the roots of terrestrial plants.They play an important role in promoting the establishment of plant communities,regulating the circulation of nutrient elements,and maintaining the stability of ecosystems.In this paper,the arbuscular mycorrhizal fungus was taken as the research object,the rhizosphere soil of 6 common shrub-grass layer plants in Fanjingshan National Nature Reserve was collected.Wet-sieving and sucroes density gradient centrifugation methods to isolate spores of AM fungi and based on morphological characters and Nested-PCR to identify species.The species diversity of AM fungi was analyzed by statistical method.The following research results were obtained:1.Through morphological identification,34 species of 11 genus of AM fungi were identified from the rhizosphere soil of 6 common shrub-grass layer plants.Including,10 species of Glomus,10 species of Acaulospora,3 species of Sclerocystis,2 species of Septoglomus,2 species of Claroideoglomus,2 species of Gigaspora,1 species of Scutellospora,1 species of Funneliformis,1 species of Ambispora,1 species of Rhizophagus,1 species of Entrophospora.Glomus and Acaulospora are dominant genera.2.Using AML1/AML2 as primers,34 spores were nested-PCR amplified to obtain 10 sequences,and 9 kinds of AM fungi were identified by phylogenetic analysis,namely Gigaspora gigantea,Acaulospora scrobiculata,Gigaspora margarita,Acaulospora mellea,Glomus flavisporum,Acaulospora koskei,Scutellospora calospora,Claroideoglomus claroideum and Claroideoglomu setunicatum.3.There are great differences in AM fungi species in rhizosphere soil of 6 plants,among which 5 species have their own AM fungal species.The endemic species in the rhizosphere soil of Iris tectorum are Glomus flavisporum,Glomus melanosporum,Sclerocystis sinuosa and Septoglomus altomontanum;the endemic species in rhizosphere soil of Indocalamus tessellatus are Glomus microaggegatum;the endemic species in rhizosphere soil of Fargesia spathacea are Acaolospora capsicula,Acaulospora sp4,Gigaspora gigantea,Rhizophagus fasciculatus,and Entrophospora infrequens;the endemic species in the rhizosphere of Camellia japonica are Glomus sp2 and Claroideoglomus claroideum;the endemic species in the rhizosphere soil of Hicriopteris chinensis is Acaulospora cavernata.The results showed that the species diversity of AM fungi was closely related to the species of symbiotic plants.4.The spore density,species richness,Shannon-Weiner index and Simpson index of AM fungi in different shrub grass layers were different.The density of spores in the rhizosphere soil of Camellia japonica is the highest(75.67 per 20 g soil),which is significantly higher than the other five plants,but the Shannon-Weiner index and Simpson index are the lowest,which are 0.91 and 0.49 respectively.The species richness of AM fungi in rhizosphere soil of Fargesia spathacea is the highest(19 species).5.RDA analysis shows that the distribution of AM fungi is closely related to soil factors.The distribution of Sclerocystis and Gigaspora is greatly affected by available potassium.The distribution of Ambispora and Acaulospora is greatly affected by pH.the distribution of Scutellospora is more affected by organic matter and total nitrogen.The distribution of glomus is greatly affected by total phosphorus,alkali hydrolyzed nitrogen and available phosphorus.