Net transfer of carbon between ectomycorrhizal tree species in the field
Net transfer of carbon between ectomycorrhizal tree species in the field
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DOI：
10.1038/41557
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发表时间：
1997-08-07
期刊：
影响因子：
64.8
通讯作者：
Molina, R
中科院分区：
文献类型：
--
作者：
Simard, SW;Perry, DA;Molina, R
不同的植物物种可以与同一种菌根真菌相容（1，2），并通过共同的菌丝体相互连接（3，4）。在实验室实验中经常测量通过相互连接的菌丝体的碳（3-5）、氮（6，7）和磷（8，9）的转移，但是不知道转移是否是双向的，是否存在一种植物超过其连接的伙伴的净增益，或者转移是否影响田间植物的性能（10，11）。使用同位素示踪剂的实验室研究表明，单向转移的幅度可以受到“接收者”植物（3，5）的阴影，“供体”植物与磷（12）施肥，或使用固氮供体植物和非固氮受体植物（13，14）的影响，表明移动可能受源-库关系的控制。在这里，我们使用相互同位素标记在外地证明双向碳转移外生菌根树种白桦和黄杉，导致净碳增益的P. menziesii。缺乏外生菌根的崖柏幼苗吸收少量的同位素，表明碳在B之间转移。papyrifera和P. menziesii主要是通过直接菌丝途径。孟山都幼苗的净增益平均占光合作用碳同位素吸收的6%。净转移量的大小受遮荫的影响，表明源-汇关系调节这种碳转移在田间条件下。
Different plant species can be compatible with the same species of mycorrhizal fungi(1,2) and be connected to one another by a common mycelium(3,4). Transfer of carbon(3-5), nitrogen(6,7) and phosphorus(8,9) through interconnecting mycelia has been measured frequently in laboratory experiments, but it is not known whether transfer is bidirectional, whether there is a net gain by one plant over its connected partner, or whether transfer affects plant performance in the field(10,11). Laboratory studies using isotope tracers show that the magnitude of one-way transfer can be influenced by shading of 'receiver' plants(3,5), fertilization of 'donor' plants with phosphorus(12), or use of nitrogen-fixing donor plants and non-nitrogen-fixing receiver plants(13,14), indicating that movement may be governed by source-sink relationships. Here we use reciprocal isotope labelling in the field to demonstrate bidirectional carbon transfer between the ectomycorrhizal tree species Betula papyrifera and Pseudotsuga menziesii, resulting in net carbon gain by P. menziesii. Thuja plicata seedlings lacking ectomycorrhizae absorb small amounts of isotope, suggesting that carbon transfer between B. papyrifera and P. menziesii is primarily through the direct hyphal pathway. Net gain by P. menziesii seedlings represents on average 6% of carbon isotope uptake through photosynthesis. The magnitude of net transfer is influenced by shading of P. menziesii indicating that source-sink relationships regulate such carbon transfer under field conditions.