Successional changes in ectomycorrhizal fungi associated with the polar willow Salix polaris in a deglaciated area in the High Arctic, Svalbard
Successional changes in ectomycorrhizal fungi associated with the polar willow Salix polaris in a deglaciated area in the High Arctic, Svalbard
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DOI：
10.1007/s00300-010-0922-9
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发表时间：
2011-05-01
期刊：
影响因子：
1.7
通讯作者：
Nakatsubo, Takayuki
中科院分区：
文献类型：
--
作者：
Fujiyoshi, Masaaki;Yoshitake, Shinpei;Nakatsubo, Takayuki
极地杨柳（Salix polaris Wahlenb.），一种菌根矮灌木，在北极斯瓦尔巴特群岛的冰川消融地区定居。阐明与S.北极冰川退缩后，我们检查了ECM真菌的多样性和密度在培养和现场条件。植物和土壤样品收集从三个网站的不同演替阶段的冰川消退区的Austre Broggerbreen，附近的Ny-lesund，斯瓦尔巴群岛。演替阶段为早期裸露地表（站点I）、过渡阶段沙柳散生定居（站点IIa和IIb）和晚期植被发育（站点III）。没有观察到ECM定植在柳树从裸露的地面在早期和短暂的阶段（站点I和IIa）收集的土壤。然而，大多数柳个人表现出ECM殖民化的土壤中收集的网站接近柳殖民地在短暂的和后期阶段（网站IIb和III）。基于分子生物学分析和操作分类单位（OTU：> 95%ITS序列相似性）的划分，我们在8个属中鉴定出15个OTU/种。优势OTU/物种的ECM真菌鉴定的瞬态和后期阶段是Geopora sp.1和Cenococcum sp.1，分别。在培养实验中，ECM多样性在后期（8个OTU/物种）比在过渡期（3个OTU/物种）更大。这一模式与实地观察一致，即，晚期位点含有更多的OTU/ECM真菌种类。这些结果表明，ECM真菌的物种多样性增加，在高北极冰川退缩后的演替过程中的优势种的变化。
Polar willow (Salix polaris Wahlenb.), a mycorrhizal dwarf shrub, colonizes recently deglaciated areas in the High Arctic, Svalbard. To clarify successional changes in ECM fungi associated with S. polaris after glacier retreat, we examined the diversity and density of ECM fungi in culture and field conditions. Plant and soil samples were collected from three sites of different successional stages in the deglaciated area of Austre Broggerbreen, near Ny-lesund, Svalbard. The successional stages were early stage with newly exposed bare ground (site I), transient stage with scattered colonization of Salix (sites IIa and IIb), and late stage with well-developed vegetation (site III). No ECM colonization on Salix was observed in soils collected from bare ground in early and transient stages (sites I and IIa). However, most Salix individuals showed ECM colonization in soils collected from sites close to Salix colonies in transient and late stages (sites IIb and III). Based on molecular analyses and operational taxonomic unit (OTU: > 95% ITS sequence similarity) delimitations, we identified 15 OTUs/species in eight genera. The dominant OTU/species of ECM fungi identified in the transient and late stages was Geopora sp.1 and Cenococcum sp.1, respectively. In the culture experiment, ECM diversity was greater in late stage (eight OTUs/species) than in transient stage (three OTUs/species). This pattern was consistent with field observations, i.e., late-stage sites contained more OTUs/species of ECM fungi. These results indicate that species diversity of ECM fungi increases and the dominant species changes with the progress of succession after glacier retreat in the High Arctic.