In forests in Mongolia, tree roots and ectomycorrhizal fungi must survive several months of soil freezing in winter. To investigate the ectomycorrhizal community after winter, we collected fine roots of Scots pine (Pinus sylvestris) and Siberian pine (Pinus sibirica) and associated soil from Nukht forest in the Bogd-Khan National Reserve, Mongolia. Soil samples were collected from frozen soil at the end of April 2016. We described the ectomycorrhizal community, and determined on ectomycorrhizal roots tips and in soils the potential activity of enzymes involved in the degradation of soil organic matter. In order to assess the temperature sensitivity of enzyme activity, potential soil enzyme activities were assayed at temperatures from 5 to 20 °C. We detected 24 different ectomycorrhizal morphotypes associated with Pinus sylvestris and Pinus sibirica, and 18 morphotypes were identified to taxa. The two Pinus species had dissimilar ectomycorrhizal communities, and only 2 ectomycorrhizal fungal taxa were common to both species. Most ectomycorrhizal taxa had measurable activity of at least one extracellular enzyme. A high contribution to the community extracellular enzyme activity was shown for both abundant and less abundant taxa. Among the eight tested soil enzymes, only the activity of leucine amino peptidase showed consistent higher Q₁₀ values at 5–15 °C than at 10–20 °C, suggesting that the enzyme is adapted to colder temperatures. Total soil N was the strongest factor explaining differences in soil enzyme potential activity. A positive relationship was found between soil N and the soil potential enzyme activity of acid phosphatase. We suggest that viable ectomycorrhizas during winter provide an advantage to Pinus sibirica and Pinus sylvestris in acquiring nutrients as soil thaws in spring.

在蒙古的森林中，树木的根和外生菌根真菌必须在冬季冻结数月的土壤中生存。为了调查冬季后的外生菌根群落，我们收集了苏格兰松（Pinus sylvestris）和西伯利亚松（Pinus sibirica）的细根）和蒙古Bogd-Khan国家自然保护区Nukht森林的相关土壤。2016年4月末从冷冻土壤中收集土壤样品。我们描述了外生菌根群落，并在外生菌根根尖和土壤中测定了参与土壤有机质降解的酶的潜在活性。为了评估酶活性的温度敏感性，在5至20°C的温度下测定了潜在的土壤酶活性。我们检测到了24种与樟子松和西伯利亚松相关的外生菌根形态，并鉴定出18种形态。两个松一个物种具有不同的外生菌根群落，并且两个物种都只有两个外生菌根真菌类群。大多数外生菌根类群具有至少一种细胞外酶的可测量活性。丰富的和不太丰富的分类单元都显示出对社区细胞外酶活性的高贡献。在八种测试的土壤酶中，只有亮氨酸氨基肽酶的活性在5–15°C时显示出始终较高的Q ₁₀值，而在10–20°C时显示出较高的Q ₁₀值，表明该酶适应于较低的温度。土壤总氮是解释土壤酶潜在活性差异的最强因素。土壤氮与酸性磷酸酶的潜在酶活性之间存在正相关关系。我们建议冬季可行的外生菌根为春季土壤融化时，西伯利亚松和樟子松获得养分。