红花尔基不同龄级天然樟子松外生菌根真菌群落结构特征

红花尔基被誉为樟子松Pinus sylvestris var. mongolica的故乡,樟子松是我国北方主要的造林树种之一,也是典型的菌根依赖型树种。研究樟子松根围外生菌根真菌（ectomycorrhizal fungi,ECMF）群落结构特征对红花尔基沙地樟子松生态系统的保护具有重要意义。本研究以红花尔基天然樟子松根围土壤为研究对象,采用Illumina MiSeq测序技术研究了4个龄级（<10、11-20、21-30和31-40年,分别称作Ⅰ、Ⅱ、Ⅲ和Ⅳ龄级）天然樟子松根围土壤ECMF群落结构特征。结果表明：（1）测序共获得87 516条ECMF序列,划分为177个OTUs（operational taxonomic units,OTU）,隶属于2个门,4个纲,12个目,26个科,43个属。（2）Ⅳ龄级中Ace丰富度指数和Shannon-Wiener多样性指数均显著高于Ⅰ龄级（P<0.05）。（3）不同龄级根围ECMF优势属占比不同,Ⅰ龄级中占比最大的为Inocybe（42.55%）;Ⅱ和Ⅲ龄级中占比最大的均为Tricholoma,分别为31.64%和27.69%;Ⅳ龄级中占比最大的为Cortinarius（28.80%）。（4）冗余分析表明,土壤pH值对ECMF的影响程度最大,其次为速效钾和碱解氮;同时,不同理化因子对群落中优势属的影响也存在差异。

Ectomycorrhizal fungal community structure characteristics of natural Pinus sylvestris var. mongolica with different age classes in Honghuaerji,Greater Khingan Mountains

Honghuaerji is known as the home of Pinus sylvestris var. mongolica, one of the main afforestation tree species in northern China with typical mycorrhizal dependence. In this study, rhizosphere soil of natural P. sylvestris var. mongolica in Honghuaerji was sampled for research object of clarifying ectomycorrhizal fungal (ECMF) community structure and protection of local ecosystem. Illumina MiSeq sequencing was used to study the ECMF community structure. P. sylvestris var. mongolica trees were divided into 4 age classes, <10, 11-20, 21-30 and 31-40 years old, respectively graded as Ⅰ, Ⅱ, Ⅲ and Ⅳ. A total of 87 516 ECMF sequences was obtained by sequencing, dividing into 177 OTUs (operational taxonomic units) belonging to 2 phyla, 4 classes, 12 orders, 26 families and 43 genera. It was showed that Ace richness index and Shannon-Wiener diversity index in Ⅳ age class were significantly higher than those in Ⅰ age class (P<0.05). The proportion of dominant genera of ECMF in different age classes was different. Inocybe (42.55%) accounted for the largest proportion in Ⅰ age class. Tricholoma accounted for the largest proportion in Ⅱ and Ⅲ age classes, being 31.64% and 27.69% respectively, while Cortinarius (28.80%) accounted for the largest proportion in Ⅳ age class. Redundancy analysis showed that soil pH had the greatest effect on ECMF, followed by available potassium and available nitrogen. The effects of different physicochemical factors on the proportion of dominant genera were also different.