Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel.
Mol Ecol. 2022 Jun;31(12):3481-3495. doi: 10.1111/mec.16477. Epub 2022 May 5.
Mycorrhizal fungi can colonize multiple trees of a single or multiple taxa, facilitating bidirectional exchange of carbon between trees. Mycorrhiza-induced carbon transfer was shown in the forest, but it is unknown whether carbon is shared symmetrically among tree species, and if not, which tree species are better donors and which are better recipients. Here, we test this question by investigating carbon transfer dynamics among five Mediterranean tree species in a microcosm system, including both ectomycorrhizal (EM) and arbuscular (AM) plants. Trees were planted together in "community boxes" using natural soil from a mixed forest plot that serves as a habitat for all five tree species and their native mycorrhizal fungi. In each box, only the trees of a single species were pulse-labelled with CO . We found that carbon transfer was asymmetric, with oak being a better donor, and pistacia and cypress better recipients. Shared mycorrhizal species may have facilitated carbon transfer, but their diversity did not affect the amount, nor timing, of the transfer. Overall, our findings in a microcosm system expose rich, but hidden, belowground interactions in a diverse population of trees and mycorrhizal fungi. The asymmetric carbon exchange among cohabiting tree species could potentially contribute to forest resilience in an uncertain future.
菌根真菌可以定殖于同一或多个分类群的多棵树中，促进树木之间的碳双向交换。在森林中已经证明了菌根诱导的碳转移，但尚不清楚碳是否在树种之间对称共享，如果不是，哪些树种是更好的供体，哪些是更好的受体。在这里，我们通过在一个微生境系统中调查五种地中海树种之间的碳转移动态来检验这个问题，包括外生菌根（EM）和丛枝菌根（AM）植物。使用来自混合林斑块的天然土壤，将树木种植在“社区箱”中，该斑块是所有五种树木及其本地菌根真菌的栖息地。在每个箱子中，只有一种树种的树木被用 13CO2 脉冲标记。我们发现碳转移是不对称的，橡树是更好的供体，而黄连木和柏木是更好的受体。共享的菌根物种可能促进了碳转移，但它们的多样性并不影响转移的数量和时间。总的来说，我们在微生境系统中的发现揭示了一个多样化的树木和菌根真菌群体中丰富但隐藏的地下相互作用。共栖树种之间的不对称碳交换可能有助于未来不确定的森林恢复力。
