Swedish University of Agricultural Sciences, Department of Soil and Environment, SE-750 07, Uppsala, Sweden.
Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, SE-750 07, Uppsala, Sweden.
Ecol Lett. 2017 Dec;20(12):1546-1555. doi: 10.1111/ele.12862. Epub 2017 Oct 22.
Plant-soil interactions link ecosystem fertility and organic matter accumulation below ground. Soil microorganisms play a central role as mediators of these interactions, but mechanistic understanding is still largely lacking. Correlative data from a coniferous forest ecosystem support the hypothesis that interactions between fungal guilds play a central role in regulating organic matter accumulation in relation to fertility. With increasing ecosystem fertility, the proportion of saprotrophic basidiomycetes increased in deeper organic layers, at the expense of ectomycorrhizal fungal species. Saprotrophs correlated positively with the activity of oxidative enzymes, which in turn favoured organic matter turnover and nitrogen recycling to plants. Combined, our findings are consistent with a fungus-mediated feedback loop, which results in a negative correlation between ecosystem fertility and below-ground carbon storage. These findings call for a shift in focus from plant litter traits to fungal traits in explaining organic matter dynamics and ecosystem fertility in boreal forests.
植物-土壤相互作用将生态系统肥力和地下有机质积累联系在一起。土壤微生物作为这些相互作用的中介，起着核心作用，但在机制理解方面仍存在很大的不足。来自针叶林生态系统的相关数据支持这样一种假设，即真菌类群之间的相互作用在调节与肥力相关的有机质积累方面起着核心作用。随着生态系统肥力的增加，在较深的有机层中，腐生担子菌的比例增加，而外生菌根真菌的比例减少。腐生菌与氧化酶的活性呈正相关，而氧化酶的活性又有利于有机质的转化和氮素向植物的再循环。总的来说，我们的研究结果与真菌介导的反馈环一致，该反馈环导致生态系统肥力与地下碳储量之间呈负相关。这些发现要求人们将关注点从植物凋落物特性转移到真菌特性，以解释北方森林的有机质动态和生态系统肥力。
