Korkama T, Pakkanen A, Pennanen T
Finnish Forest Research Institute (Metla) Vantaa Research Unit, PO Box 18, FI-01301, Vantaa, Finland.
New Phytol. 2006;171(4):815-24. doi: 10.1111/j.1469-8137.2006.01786.x.
In northern boreal forests, the diversity of ectomycorrhizal (ECM) species is much greater than that of their host trees. This field study investigated the role of individual trees in shaping the ECM community. We compared ECM communities of eight Norway spruce (Picea abies) clones planted in a clear-cut area in 1994 with a randomized block design. In 2003, the ECM fungi were identified from randomly sampled root tips using denaturing gradient gel electrophoresis (DGGE) and rDNA internal transcribed spacer (ITS) sequence similarity. ECM diversity varied among clone groups, showing twofold growth differences. Moreover, according to detrended correspondence analysis (DCA), ECM community structure varied not only among but also within slow-growing or fast-growing clones. Results suggest that ECM diversity and community structure are related to the growth rate or size of the host. A direct or indirect influence of host genotype was also observed, and we therefore suggest that individual trees are partly responsible for the high diversity and patchy distribution of ECM communities in boreal forests.
在北方针叶林中，外生菌根（ECM）物种的多样性远高于其寄主树木。这项实地研究调查了单株树木在塑造ECM群落中的作用。我们采用随机区组设计，比较了1994年种植在一片皆伐区域的八个挪威云杉（Picea abies）无性系的ECM群落。2003年，利用变性梯度凝胶电泳（DGGE）和rDNA内转录间隔区（ITS）序列相似性，从随机采样的根尖中鉴定出ECM真菌。ECM多样性在无性系组间存在差异，呈现出两倍的生长差异。此外，根据去趋势对应分析（DCA），ECM群落结构不仅在生长缓慢或快速生长的无性系之间存在差异，在无性系内部也存在差异。结果表明，ECM多样性和群落结构与寄主的生长速率或大小有关。还观察到寄主基因型的直接或间接影响，因此我们认为单株树木对北方森林中ECM群落的高多样性和斑块状分布负有部分责任。
