Individual tree genotypes do not explain ectomycorrhizal biodiversity in soil cores of a pure stand of beech (Fagus sylvatica L.)
Individual tree genotypes do not explain ectomycorrhizal biodiversity in soil cores of a pure stand of beech (Fagus sylvatica L.)
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DOI：
10.1007/s00468-013-0881-1
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发表时间：
2013-10-01
影响因子：
2.3
通讯作者：
Huettl, Reinhard F.
中科院分区：
文献类型：
--
作者：
Bubner, Ben;Fladung, Matthias;Huettl, Reinhard F.
生态位分化是高度外生菌根多样性的常见解释。在单一栽培和小空间尺度上，可能提供生态位的可变因素的数量减少。尽管如此，即使在有限的土芯体积中，通常也会发现不止一种外生菌根物种。我们测试了这样的假设：不同个体山毛榉基因型的根在德国东北低地的纯山毛榉（Fagus sylvatica L.）林中在小空间尺度上提供了生态位。通过 ITS 测序和系统图确定，14 个外生菌根物种沿着 81 m 长的横断面（有 10 个断面点）呈斑状分布。通过微卫星 PCR 对三个物种最丰富的土壤核心和周围山毛榉的所有根段进行了基因分型。在三个土壤核心中的每一个中，都存在两种宿主基因型的根，对应于两棵最接近的成熟树木。我们发现，即使在我们的研究提供的高物种分辨率下，不同的根基因型也不携带不同的外生菌根物种。因此，在分析的山毛榉林中，树木基因型有助于外生菌根生物多样性的假设必须被拒绝。讨论了勘探类型和随机过程，作为分析土壤核心中物种丰富度和分布的替代解释。据我们所知，这是第一份将土壤核心的外生菌根生物多样性与被子植物宿主的个体基因型联系起来的报告。
Niche differentiation is a common explanation for high ectomycorrhizal diversity. In monocultures and on small spatial scales, the number of variable factors that may provide niches decreases. Still, even in the restricted volume of a soil core, typically more than one ectomycorrhizal species is found. We tested the hypothesis that roots of different individual beech genotypes provide niches on a small spatial scale in a pure beech (Fagus sylvatica L.) stand in the North-eastern Lowlands of Germany. Fourteen ectomycorrhizal species, as determined by ITS sequencing and phylograms were patchily distributed along an 81 m long transect with ten transect points. All root segments in the three species richest soil cores and the surrounding beeches were genotyped by microsatellite PCR. In each of the three soil cores, roots of two host genotypes were present that corresponded to the two closest mature trees. We found that the different root genotypes did not carry different sets of ectomycorrhizal species even at the high species resolution provided through our study. Therefore, the hypothesis of tree genotypes contributing to ectomycorrhizal biodiversity at the analyzed beech stand has to be rejected. Exploration types and stochastic processes are discussed as alternative explanations for the species richness and distributions in the analyzed soil cores. To the best of our knowledge, this is the first report that links ectomycorrhizal biodiversity in a soil core to the individual genotype of an angiosperm host.