Species diversity of arbuscular mycorrhizal fungi of Stipa L. in alpine grassland in northern Tibet in China

This study was based on 4 Stipa species(including 3 specific Qinghai-Tibet Plateau species and 1 widely-spreading species)in the alpine grassland in northern Tibet in China,through arbuscular mycorrhizal fungi(AMF)enrichment culture of soil samples of mycorrhizosphere and spore morphology identification.The results showed that:(1)In the cold and dry high-altitude environment,fungi of the Glomus genus played a outstanding role and had great significance in the composition of AMF population among different rhizosphere stipa,and their spore density,species number,relative abundance and importance value were all of significance(P≤0.05),and greater than those in Acaulospora and Scutellospora.(2)The composition of stipa species had important influences on species diversity of AM fungi,Shannon-Weiner index and species evenness index in widely-spreading species Stipa glareosa were relatively the highest(1.79 and 0.72,respectively),then from higher to lower,Stipa subsessiliflora var.basiplumosa,Stipa purpurea and Stipa roborowskyi.However,AMF proliferative capacity of mycorrhizosphere of specific Qinghai-Tibet Plateau stipa genus was stronger,and spore density in Stipa subsessiliflora var.basiplumosa,Stipa purpurea and Stipa roborowskyi was higher than Stipa glareosa by 57.8%,48.7% and 62.4%,respectively.(3)In various soils with mycorrhizosphere of Stipa L.,the distribution features of AM fungi populations showed that same AM fungi species(sharing species)and dominant species(F50%)were much more and difference between dominant species was great.This feature revealed complexity of AM fungi population composition,and high adaptability and synergy of AM fungi in the cold and dry plateau environment.(4)The relative abundance of the AMF dominant species in different rhizosphere of 4 Stipa L.plants was 78.2%—92.4%(the average was 85.7%),and these dominant species played an important role in population composition of AM fungi,wherein,spore density in G.claroideum accounted for 50.2%—71.9% of dominant AM fungi species of 4 Stipa L.plants.