Douglas-fir ectomycorrhizae in 40- and 400-year-old stands: mycobiont availability to late successional western hemlock
Douglas-fir ectomycorrhizae in 40- and 400-year-old stands: mycobiont availability to late successional western hemlock
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DOI：
10.1007/s00572-004-0339-9
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发表时间：
2005-07
期刊：
影响因子：
3.9
通讯作者：
Thomas R. Horton;R. Molina;K. Hood
中科院分区：
文献类型：
--
作者：
Thomas R. Horton;R. Molina;K. Hood
在典型林分发育的两个时间点，通过从混交林中的道格拉斯冷杉和西部铁杉的根中鉴定出EM真菌，研究了含有早期演替道格拉斯冷杉和演替后期西部铁杉的林分中的外生菌根真菌。在一片早期的森林中，采集了西方铁杉幼苗和混交的40年生道格拉斯冷杉的EM根。在晚更生阶段的森林中，两种树种的EM根都是在一个400年生的林分中采集的。在这项描述性研究中，我们使用分子方法从田间样本中鉴定共生体。在早期的系列研究中，以生物量计的西部铁杉根尖95%被真菌定植，也定植于道格拉斯冷杉根部。这一结果支持了西部铁杉与真菌在Douglas-Fir EM网络中存在关联的预测。在同一项研究中，道格拉斯冷杉特有的真菌侵占了其EM根尖的14%。在后期的系列研究中，14%的西部铁杉根尖被与道格拉斯冷杉相关的真菌侵占，这一结果受到采样问题的强烈影响，可能代表了对这种旧生长环境中多宿主真菌的保守估计。在过去的生长研究中，道格拉斯冷杉特有的真菌在24个土壤样本中的5个样本中的紧密珊瑚丛中定居了25%的根尖生物量。这项研究揭示的趋势证实了早先的研究，即EM植物的混合群落中存在多种寄主真菌的优势。寄主专一性真菌在这些林分中的作用尚不清楚。
We investigated ectomycorrhizal (EM) fungi in forest stands containing both early successional Douglas-fir and late successional western hemlock at two points in the typical stand development by identifying EM fungi from roots of Douglas-fir and western hemlock in mixed stands. In an early seral stage forest, EM roots of western hemlock seedlings and intermingling 40-year-old Douglas-fir were sampled. In a late seral stage forest, EM roots of trees of both species were sampled in a 400-year-old stand. We use molecular approaches to identify the symbionts from field samples in this descriptive study. In the early seral stage study, >95% of the western hemlock root tips by biomass were colonized by fungi also colonizing Douglas-fir roots. This result supports the prediction that western hemlock can associate with fungi in Douglas-fir EM networks. In the same study, fungi specific to Douglas-fir colonized 14% of its EM root tips. In the late seral stage study, 14% of the western hemlock root tips were colonized by fungi also observed in association with Douglas-fir, a result strongly influenced by sampling issues and likely represents a conservative estimate of multiple host fungi in this old growth setting. Fungi specific to Douglas-fir colonized 25% of its root tip biomass in the old growth study, in tight coralloid clusters within five of the 24 soil samples. The trends revealed in this study corroborate earlier studies suggesting a predominance of multiple host fungi in mixed communities of EM plants. The role of host-specific fungi in these stands remains unclear.