LTER: Microbial Ecology of Ectomycorrhizal Mats in a Douglas-Fir Ecosystem

在太平洋西北部针叶林的土壤中，至少有两种外生菌根真菌，子宫菌根和蒙氏Gautieria monticola，形成广泛的菌丝席。在世界各地的针叶林和落叶林中，其他海地属植物形成了类似的席地，包括与桉树相关的加氏海地属植物。初步研究表明，与邻近的未定植土壤相比，以前两种真菌为主的根际群落的微生物生物量、呼吸速率和7种负责有机物分解的酶的水平显著提高。由于这些地垫为研究外生菌根对根际群落微生物生态的影响提供了离散的单元，我们建议将上述三种地垫群落与未定植的土壤进行比较：真菌和细菌生物量、群落呼吸和酶活性；氮和磷在不稳定池和不稳定池中的分配；基质化学对酶活性的影响纯真菌培养产酶；酚偶联酶在根际过程中的作用。

At least two ectomycorrhizal fungi, Hysterangium setchellii and Gautieria monticola, form extensive hyphal mats in the soils of coniferous forests of the Pacific Northwest. Other Hysterangium species form similar mats in coniferous and deciduous forests throughout the world, including H. gardneri in association with Eucalyptus. Preliminary research has demonstrated that the rhizosphere communities dominated by the first two fungi have significantly elevated microbial biomass, respiration rates and altered levels of seven enzymes responsible for organic matter decomposition when compared to adjacent uncolonized soils. Since these mats offer discrete units to study the influence of ectomycorrhizae on the microbial ecology of the rhizosphere community, we propose to compare the above three mat communities with uncolonized soils in terms of: fungal and bacterial biomass, community respiration and enzyme activities; the partitioning of nitrogen and phosporus into labile and recalcitrant pools; the effects of mat chemistry on enzyme activities; enzyme production by pure fungal cultures; and the role of phenolic-coupling enzymes in rhizosphere processes.