呼伦贝尔沙地樟子松根内真菌群落结构与功能群特征

为揭示呼伦贝尔沙地樟子松根内真菌群落结构和功能群特征, 以呼伦贝尔沙地樟子松天然林和不同林龄人工林为研究对象, 采用野外调查和分子生物学相结合的方法, 鉴定并分析沙地樟子松根内真菌群落结构和功能群特征。在呼伦贝尔沙地樟子松根尖样品中共获得520个真菌 OTUs, 隶属于5门87科197属, 其中担子菌门(Basidiomycota)和子囊菌门(Ascomycota)的相对丰度较高, 分别为54.98%和39.27%。天然林优势菌属 为 双 子 担 子 菌 属 (Geminibasidium) 、 红 菇 属 (Russula) 和 Phialocephala, 人 工 林 优 势 菌 属 为 乳 牛 肝 菌 属(Suillus)、Phialocephala 和口蘑属(Tricholoma), 其余菌属的相对丰度随林龄的变化波动较大。沙地樟子松人工林根内真菌α多样性指数随林龄增长均呈降低趋势, 成熟林根内真菌α多样性指数显著低于沙地樟子松近熟林、中龄林和天然林(P<0.05)。沙地樟子松天然林与人工林根内真菌群落结构变异性较小。其中, 天然林与成熟林根内真菌群落结构差异较大, 与近熟林根内真菌群落结构最接近。共生营养型真菌比例随林龄增长而逐渐增大, 腐生营养型和病理营养型真菌比例随林龄增长逐渐减小; 天然林与近熟林共生营养型真菌的占比较为接近, 腐生营养型真菌在天然林中占比较大。沙地樟子松根内真菌群落结构复杂, 物种丰富多样, 外生菌根真菌和未定义腐生菌为主要功能类群, 部分真菌在不同林分的生态策略存在差异。

Community Structure and Functional Groups of Fungi in the Roots Associated with Pinus sylvestri var. mongolica in the Hulunbuir Sandy Land

To reveal the fungal community structure and functional groups in the roots associated with P. sylvestris, natural forest and different-aged plantations were analyzed using field investigation and molecular biotechnology in the Hulunbuir Sandy Land. 520 fungal OTUs were obtained from root tip samples of P. sylvestris, and belonged to 197 genera, 87 families, 5 phyla. Basidiomycota and Ascomycota had higher relative abundances, accounted for 54.98% and 39.27% respectively. The dominant bacteria in natural forest were Geminibasidium, Russula and Phialocephala, whereas the dominant bacteria in plantation were Suillus, Phialocephala and Tricholoma. Further, the relative abundance of other bacteria fluctuated with the stand age. The α diversity index of fungi in the roots of P. sylvestris plantation decreased gradually with the increasing of stand age. Among the different stands, the fungal diversity in the roots of mature forest was significantly lower than that in near-mature and middle-aged plantations as well as natural forest (P<0.05). Although the fungal community composition associated with P. sylvestris natural forest and plantations had stable variability, and near-mature forest is the closest to natural forest, natural forest and mature plantation obviously differed in the composition of fungal community. The proportion of symbiotic trophic fungi increased with the increasing of stand age. Conversely, the saprophytic and pathological trophic fungi decreased with the aging forest. The proportion of symbiotic trophic fungi in natural forest was similar with near-mature plantation, however saprophytic trophic fungi was the dominant type in natural forest. In the Hulunbuir Sandy Land, the fungal community in the root of P. sylvestris has complex structure and diverse species. The main functional groups are ectomycorrhizal and undefined saprophytic fungi. Some fungi show different ecological strategies in different stands.