Institute of Microbiology, University of Innsbruck, Innsbruck, Austria.
Microb Ecol. 2012 Jul;64(1):79-90. doi: 10.1007/s00248-011-0001-y. Epub 2012 Jan 12.
Soil microbial communities follow distinct seasonal cycles which result in drastic changes in processes involving soil nutrient availability. The biomass of fungi has been reported to be highest during winter, but is fungal growth really occurring in frozen soil? And what is the effect of plant cover on biomass formation and on the composition of fungal communities? To answer these questions, we monitored microbial biomass N, ergosterol, and the amount of fungal hyphae during summer and winter in vegetated and unvegetated soils of an alpine primary successional habitat. The winter fungal communities were identified by rDNA ITS clone libraries. Winter soil temperatures ranged between -0.6°C and -0.1°C in snow-covered soil. We found distinct seasonal patterns for all biomass parameters, with highest biomass concentrations during winter in snow-covered soil. The presence of plant cover had a significant positive effect on the amount of biomass in the soil, but the type of plant cover (plant species) was not a significant factor. A mean hyphal ingrowth of 5.6 m g(-1) soil was detected in snow-covered soil during winter, thus clearly proving fungal growth during winter in snow-covered soil. Winter fungal communities had a typical species composition: saprobial fungi were dominating, among them many basidiomycete yeasts. Plant cover had no influence on the composition of winter fungal communities.
土壤微生物群落遵循明显的季节性周期，这导致涉及土壤养分有效性的过程发生剧烈变化。真菌生物量据报道在冬季最高，但真菌生长真的会在冻土中发生吗？植物覆盖对生物量形成和真菌群落组成有什么影响？为了回答这些问题，我们在高山原生演替生境的植被和无植被土壤中，监测了夏季和冬季微生物生物量 N、麦角固醇和真菌菌丝数量。冬季土壤温度在有雪覆盖的土壤中在-0.6°C 和-0.1°C 之间。我们发现所有生物量参数都有明显的季节性模式，在有雪覆盖的土壤中冬季的生物量浓度最高。植物覆盖的存在对土壤中生物量的数量有显著的积极影响，但植物覆盖的类型（植物物种）不是一个显著的因素。在冬季有雪覆盖的土壤中检测到平均 5.6 m g(-1) 土壤的菌丝内生长，因此清楚地证明了在有雪覆盖的土壤中冬季真菌生长。冬季真菌群落具有典型的物种组成：腐生真菌占主导地位，其中包括许多担子菌酵母。植物覆盖对冬季真菌群落的组成没有影响。
