梵净山不同针叶林土壤丛枝菌根真菌多样性研究

Diversity of Soil Arbuscular Mycorrhizal Fungi in Different Coniferous Forests in Fanjing Mountain

[目的]通过研究梵净山不同针叶林土壤中丛枝菌根(arbuscular mycorrhizal,AM)真菌的多样性及分布,进一步探寻影响AM真菌分布和多样性的环境因子。[方法]采集梵净山7种针叶林根围土壤,利用湿筛倾析—蔗糖离心法和形态鉴定法对AM真菌孢子进行分离鉴定,并对孢子多样性指数进行测定和计算。[结果]梵净山7种针叶林根围土壤共鉴定出10属29种AM真菌,物种丰富;无梗囊霉属(Acaulospora)重要值达67.74%,为优势属;球囊霉属(Glomus)和硬囊霉属(Sclerocystis)主要分布于低海拔针叶林根围土壤中,随着海拔的升高,无梗囊霉属的重要值上升,为高海拔区域的优势属。长苞铁杉林和杉木林根围土壤中AM真菌的孢子密度、物种丰富度和Shannon-Wiener指数分别为最低和最高;杉木林和马尾松林根围土壤中AM真菌的Sorenson相似性系数达0.7568,为极度相似。[结论]针叶林生态系统中海拔是影响AM真菌种属分布和多样性差异的重要环境因子,也是导致林型差异的重要原因。在同一海拔下,不同针叶林及林下植物是影响AM真菌种属分布和多样性差异的重要因子。

[Purpose]To study the environmental factors influencing distribution and diversity of arbuscular mycorrhizal(AM)fungi,by investigating the diversity and distribution of AM fungi in soils from different coniferous forests in Fanjing Mountain.[Methods]A total of seven kinds of rhizosphere soil in coniferous forest were collected,and wet sieve decantation-sucrose centrifugation method and morphological identification method were used to separate and identify AM fungal spores,and determine the spore diversity index.[Results]AM fungi species in the rhizosphere soil of seven kinds of coniferous forests in Fanjing Mountain were rich and diverse,and a total of 29 species in 10 genera had been identified.Acaulospora had an important value of 67.74%,which was the dominant genus;Glomus and Sclerocystis were mainly distributed in rhizosphere soil of coniferous forests at low altitude;the important value of Acaulospora increased with the altitude increasing, which was the dominant genus at high altitude. The spore density, species abundance and Shannon- Wiener index of AM fungi in the rhizosphere soil of Tsuga longibracteata forest and Cunninghamia lanceolate forest were the lowest and highest, respectively. The species of AM fungi in the rhizo-sphere soil of C. lanceolata forest and Pinus massoniana forest were extremely similar, and the Sorenson similarity coefficient was 0.756 8. [Conclusion]In coniferous ecosystems, altitude is an important environmental factor affecting differences in the distribution and diversity of AM fungal species, which is also an important contributor to the differences in forest types. At the same altitude, different coniferous and understory plants are important factors influencing differences in the genus distribution and diversity of AM fungi.