PDF(Pubmed)
Abstract：
Differences between arbuscular (AM) and ectomycorrhizal (EcM) trees strongly influence forest ecosystem processes, in part through their impact on saprotrophic fungal communities. Ericoid mycorrhizal (ErM) shrubs likely also impact saprotrophic communities given that they can shape nutrient cycling by slowing decomposition rates and intensifying nitrogen limitation. We investigated the depth distributions of saprotrophic and EcM fungal communities in paired subplots with and without a common understory ErM shrub, mountain laurel (Kalmia latifolia L.), across an AM to EcM tree dominance gradient in a temperate forest by analyzing soils from the organic, upper mineral (0-10 cm), and lower mineral (cumulative depth of 30 cm) horizons. The presence of K. latifolia was strongly associated with the taxonomic and functional composition of saprotrophic and EcM communities. Saprotrophic richness was consistently lower in the Oa horizon when this ErM shrub species was present. However, in AM tree-dominated plots, the presence of the ErM shrub was associated with a higher relative abundance of saprotrophs. Given that EcM trees suppress both the diversity and relative abundance of saprotrophic communities, our results suggest that separate consideration of ErM shrubs and EcM trees may be necessary when assessing the impacts of plant mycorrhizal associations on belowground communities.
摘要：
丛枝（AM）和外生菌根（EcM）树之间的差异强烈影响森林生态系统过程，部分原因是它们对腐生真菌群落的影响。Ericoid菌根（ErM）灌木也可能会影响腐殖质群落，因为它们可以通过减慢分解速率和加剧氮限制来塑造养分循环。我们调查了有或没有共同的林下ErM灌木的成对子图中腐生和EcM真菌群落的深度分布，山月桂树（KalmialatifoliaL.），通过从有机物质分析土壤，在温带森林中跨越AM到EcM树的优势梯度，上部矿物（0-10厘米），和较低的矿物（30厘米的累积深度）层。K.latifolia的存在与腐生和外生菌根群落的分类学和功能组成密切相关。当存在这种ErM灌木物种时，Oa地平线上的腐化丰富度一直较低。然而,在AM树为主的地块中，ErM灌木的存在与腐生的相对丰度较高有关。鉴于EcM树抑制了腐生群落的多样性和相对丰度，我们的结果表明，在评估植物菌根协会对地下社区的影响时，可能需要分别考虑ErM灌木和EcM树。
