Accounting for Carbon Flux to Mycorrhizal Fungi May Resolve Discrepancies in Forest Carbon Budgets
Accounting for Carbon Flux to Mycorrhizal Fungi May Resolve Discrepancies in Forest Carbon Budgets
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DOI：
10.1007/s10021-019-00440-3
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发表时间：
2019-09
期刊：
影响因子：
3.7
通讯作者：
A. Ouimette;S. Ollinger;L. Lepine;Ryan B. Stephens;R. J. Rowe;M. Vadeboncoeur;S. J. Tumber-Dávila;E. Hobbie
中科院分区：
文献类型：
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作者：
A. Ouimette;S. Ollinger;L. Lepine;Ryan B. Stephens;R. J. Rowe;M. Vadeboncoeur;S. J. Tumber-Dávila;E. Hobbie
植物生长不同组成部分之间的碳（C）通量对森林生态系统碳循环很重要，并且受到物种组成和资源可用性的强烈影响。尽管菌根真菌对于养分获取至关重要，并且可以获得年净初级生产力的很大一部分，但大多数研究并未明确将菌根真菌的碳通量纳入生态系统碳预算。我们测量了不同物种组成的温带森林中植物成分（叶子、木材、细根）和菌根真菌的年产量。使用质量平衡和同位素技术估计菌根真菌的产量。植物总产量从几乎纯粹的落叶阔叶林中的约 600 g C m−2y−1 到以针叶树为主的林中的约 300 g C m−2y−1 不等。相比之下，以针叶树为主的林分中菌根真菌的产量最高，从落叶阔叶林中的小于 25 g C m−2y−1 到几乎纯针叶林中的超过 175 g C m−2y−1 不等。同位素数据表明，树种组成和生态系统氮 (N) 可用性都会影响真菌的生产速率。对低氮、针叶树为主的菌根真菌的大量投资表明，全面核算植物和真菌成分的生态系统碳通量可能有助于解决目前在大规模森林碳预算中观察到的差异，特别是跨森林类型。
Carbon (C) fluxes among different components of plant growth are important to forest ecosystem C cycling and are strongly influenced by species composition and resource availability. Although mycorrhizal fungi are crucial for nutrient acquisition and can receive a large fraction of annual net primary production, most studies do not explicitly include carbon flux to mycorrhizal fungi in ecosystem C budgets. We measured annual production of plant components (foliage, wood, fine roots) and mycorrhizal fungi across temperate forest stands varying in species composition. Production of mycorrhizal fungi was estimated using both mass balance and isotopic techniques. Total plant production varied from about 600 g C m−2y−1in nearly pure deciduous broadleaf stands down to about 300 g C m−2y−1in conifer-dominated stands. In contrast, the production of mycorrhizal fungi was highest in conifer-dominated stands, varying from less than 25 g C m−2y−1in deciduous broadleaf stands to more than 175 g C m−2y−1in nearly pure conifer stands. Isotopic data indicated that both tree species composition and ecosystem nitrogen (N) availability influenced rates of fungal production. The large investment in mycorrhizal fungi in low-N, conifer-dominated stands demonstrated that a full accounting of ecosystem carbon fluxes to plant and fungal components may help resolve current discrepancies observed in broadscale forest carbon budgets, especially across forest types.