Sterkenburg Erica, Bahr Adam, Brandström Durling Mikael, Clemmensen Karina E, Lindahl Björn D
Uppsala BioCenter, Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Box 7026, Uppsala, SE-750 07, Sweden.
Microbial Ecology, Department of Biology, Lund University, Lund, SE-223 62, Sweden.
New Phytol. 2015 Sep;207(4):1145-58. doi: 10.1111/nph.13426. Epub 2015 May 7.
Boreal forests harbour diverse fungal communities with decisive roles in decomposition and plant nutrition. Although changes in boreal plant communities along gradients in soil acidity and nitrogen (N) availability are well described, less is known about how fungal taxonomic and functional groups respond to soil fertility factors. We analysed fungal communities in humus and litter from 25 Swedish old-growth forests, ranging from N-rich Picea abies stands to acidic and N-poor Pinus sylvestris stands. 454-pyrosequencing of ITS2 amplicons was used to analyse community composition, and biomass was estimated by ergosterol analysis. Fungal community composition was significantly related to soil fertility at the levels of species, genera/orders and functional groups. Ascomycetes dominated in less fertile forests, whereas basidiomycetes increased in abundance in more fertile forests, both in litter and humus. The relative abundance of mycorrhizal fungi in the humus layer remained high even in the most fertile soils. Tolerance to acidity and nitrogen deficiency seems to be of greater importance than plant carbon (C) allocation patterns in determining responses of fungal communities to soil fertility, in old-growth boreal forests.
北方森林拥有多样的真菌群落，这些群落在分解和植物营养方面起着决定性作用。尽管北方植物群落沿土壤酸度和氮（N）有效性梯度的变化已有详尽描述，但对于真菌分类群和功能群如何响应土壤肥力因素却知之甚少。我们分析了来自25片瑞典原始森林的腐殖质和凋落物中的真菌群落，这些森林涵盖了从富氮的欧洲云杉林到酸性且贫氮的欧洲赤松林。利用ITS2扩增子的454焦磷酸测序来分析群落组成，并通过麦角固醇分析估算生物量。真菌群落组成在物种、属/目和功能群水平上均与土壤肥力显著相关。在较贫瘠的森林中，子囊菌占主导，而在较肥沃的森林中，无论是凋落物还是腐殖质中，担子菌的丰度都有所增加。即使在最肥沃的土壤中，腐殖质层中菌根真菌的相对丰度仍保持较高。在北方原始森林中，在决定真菌群落对土壤肥力的响应方面，耐酸性和耐氮缺乏似乎比植物碳（C）分配模式更为重要。
