Can isotopic fractionation during respiration explain the 13C-enriched sporocarps of ectomycorrhizal and saprotrophic fungi?
Can isotopic fractionation during respiration explain the 13C-enriched sporocarps of ectomycorrhizal and saprotrophic fungi?
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呼吸过程中的同位素分馏能否解释外生菌根真菌和腐养真菌富含 13 C 的子实体？
DOI：
10.1111/j.1469-8137.2007.02332.x
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
A. Ekblad
中科院分区：
文献类型：
--
作者：
B. Boström;D. Comstedt;A. Ekblad
真菌相对于植物材料富集 (13)C 的机制尚不清楚，并且限制了稳定同位素在土壤碳循环研究中的使用。在这里，我们通过比较来自挪威云杉林中收集的 16 种外生菌根或腐生真菌的呼吸 CO(2)、子实体及其相关植物材料的 delta(13)C 特征，研究了呼吸过程中的同位素分馏是否有助于这种模式。呼吸CO(2)与子实体的同位素组成呈正相关。 CO(2) 和子实体之间的 delta(13)C 差异通常很小，16 个物种中的 9 个物种 < +/-1 千分之 1，所有调查物种的平均变化为 0.04 千分之 0.04。然而，当单独分析真菌群体时，六分之三的外生菌根担子菌呼吸富含 (13)C 的 CO(2)（高达 1.6%），而五分之三的多孔菌呼吸贫（13）C 的 CO(2)（高达 1.7%；P < 0.05）。与木材、枯枝落叶或根相比，CO(2) 和子实体总是富含 (13)C。 (13)C 耗尽的 CO(2) 的损失可能使 (13)C 中的某些物种富集。然而，与植物材料相比，CO(2) 始终富含 (13)C，这意味着必须找到其他过程来解释与植物材料相比，真菌生物质始终富含 (13)C。
The mechanism behind the (13)C enrichment of fungi relative to plant materials is unclear and constrains the use of stable isotopes in studies of the carbon cycle in soils. Here, we examined whether isotopic fractionation during respiration contributes to this pattern by comparing delta(13)C signatures of respired CO(2), sporocarps and their associated plant materials, from 16 species of ectomycorrhizal or saprotrophic fungi collected in a Norway spruce forest. The isotopic composition of respired CO(2) and sporocarps was positively correlated. The differences in delta(13)C between CO(2) and sporocarps were generally small, < +/-1 per thousand in nine out of 16 species, and the average shift for all investigated species was 0.04 per thousand. However, when fungal groups were analysed separately, three out of six species of ectomycorrhizal basidiomycetes respired (13)C-enriched CO(2) (up to 1.6 per thousand), whereas three out of five species of polypores respired (13)C-depleted CO(2) (up to 1.7 per thousand; P < 0.05). The CO(2) and sporocarps were always (13)C-enriched compared with wood, litter or roots. Loss of (13)C-depleted CO(2) may have enriched some species in (13)C. However, that the CO(2) was consistently (13)C-enriched compared with plant materials implies that other processes must be found to explain the consistent (13)C-enrichment of fungal biomass compared with plant materials.