Microbial Ecology, Department of Biology, Lund University, Lund, Sweden.
Mycorrhiza. 2012 Nov;22(8):615-21. doi: 10.1007/s00572-012-0438-y. Epub 2012 Mar 27.
Ectomycorrhizal (ECM) fungi are efficient at taking up phosphorus (P) from mineral sources, such as apatite, which are not easily available to the host trees. Since ECM fungal species differ in P uptake rates, it can be expected that the composition of the ECM fungal community will change upon exposure to apatite, provided that the P transfer is rewarded by more carbon being transferred to the fungal symbiont. Control and apatite-amended mesh bags were buried in pairs in the humus layer of a P-poor Norway spruce forest. The ECM fungal community that colonized these bags was analyzed by DNA extraction, PCR amplification of the internal transcribed spacer (ITS) region, cloning, and random sequencing. Fungal biomass was estimated by ergosterol analysis. No change in the ECM fungal community structure was seen after 5 years of apatite exposure, although the fungal biomass increased threefold upon apatite amendment. Our results indicate that host trees enhance carbon allocation to ECM fungi colonizing P sources in P-poor forests but the lack of change in the composition of the ECM fungal community suggests that P transfer rates were similar among the species. Alternatively, higher P transfer among certain species was not rewarded with higher carbon transfer from the host.
外生菌根 (ECM) 真菌能够有效地从矿物源（如磷灰石）中吸收磷，而这些磷对宿主树木来说不易获得。由于 ECM 真菌物种在磷吸收速率上存在差异，因此可以预期，在接触到磷灰石的情况下，ECM 真菌群落的组成将会发生变化，前提是磷的转移会得到更多的碳转移给真菌共生体的回报。对照和添加磷灰石的网袋成对埋在贫磷挪威云杉林的腐殖质层中。通过 DNA 提取、内部转录间隔区 (ITS) 区域的 PCR 扩增、克隆和随机测序来分析这些袋子中定殖的 ECM 真菌群落。通过麦角固醇分析来估计真菌生物量。尽管在添加磷灰石后，真菌生物量增加了两倍，但经过 5 年的磷灰石暴露后，ECM 真菌群落结构没有发生变化。我们的研究结果表明，宿主树木会增加向定殖在贫磷森林中磷源的 ECM 真菌分配碳，但 ECM 真菌群落组成没有变化表明，不同物种之间的磷转移率相似。或者，某些物种之间更高的磷转移并没有得到来自宿主的更高碳转移的回报。
