Distinct carbon fractions drive a generalisable two‐pool model of fungal necromass decomposition
Distinct carbon fractions drive a generalisable two‐pool model of fungal necromass decomposition
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DOI：
10.1111/1365-2435.13728
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发表时间：
2020-12
影响因子：
5.2
通讯作者：
C. See;Christopher W. Fernandez;Anna M. Conley;L. C. DeLancey;K. Heckman;P. Kennedy;S. Hobbie
中科院分区：
文献类型：
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作者：
C. See;Christopher W. Fernandez;Anna M. Conley;L. C. DeLancey;K. Heckman;P. Kennedy;S. Hobbie
处理编辑：巴勃罗加西亚-帕拉西奥斯摘要1.真菌代表土壤中碳（C）和氮（N）的快速循环库。了解这个池如何影响土壤养分的可用性和有机质通量的不确定性，阻碍了真菌坏死物分解的动力学和驱动程序。2.在这里，我们评估了预测真菌坏死物质分解过程中质量损失的常见模型的一般性，并将所得参数与坏死物质基质化学联系起来。我们分解了28种不同类型的真菌necromass在实验室的缩影超过90天的时间内，测量质量损失的所有类型，和N释放的一个子集的类型。我们使用以下方法表征了每种坏死块类型的初始化学性质：（a）通常用于植物组织的纤维分析方法，（B）初始黑色素和氮（N）浓度，以及（c）傅立叶变换红外（FTIR）光谱法，以评估与常见生物分子相关的键的存在。3.我们发现普遍支持的渐近模型的分解，假设真菌necromass由一个指数分解的“快”池，和一个“慢”池，以接近零的速度分解。快速池衰减速率（k）的最强预测因子是细胞可溶性成分的比例，虽然初始N浓度也预测k，但更弱。慢池的大小是最好的预测酸不可水解的馏分，这是正相关的黑色素相关的芳香族化合物。氮动力学变化的necromass类型，范围从净N释放净固定。固定的N的最大量呈负相关的细胞可溶性含量和K，与细胞壁多糖的FTIR光谱呈正相关。4.总的来说，我们的研究结果表明，真菌necromass在土壤中的分解可以被描述为有两个不同的阶段，由不同的成分驱动的基板C化学，与土壤中的氮的可用性和有机质积累率的影响。
Handling Editor: Pablo García-Palacios Abstract 1. Fungi represent a rapidly cycling pool of carbon (C) and nitrogen (N) in soils. Understanding of how this pool impacts soil nutrient availability and organic matter fluxes is hindered by uncertainty regarding the dynamics and drivers of fungal necromass decomposition. 2. Here we assessed the generality of common models for predicting mass loss during fungal necromass decomposition and linked the resulting parameters to necromass substrate chemistry. We decomposed 28 different types of fungal necromass in laboratory microcosms over a 90-day period, measuring mass loss on all types, and N release on a subset of types. We characterised the initial chemistry of each necromass type using: (a) fibre analysis methods commonly used for plant tissues, (b) initial melanin and nitrogen (N) concentrations and (c) Fourier transform infrared (FTIR) spectroscopy to assess the presence of bonds associated with common biomolecules. 3. We found universal support for an asymptotic model of decomposition, which assumes that fungal necromass consists of an exponentially decomposing ‘fast’ pool, and a ‘slow’ pool that decomposes at a rate approaching zero. The strongest predictor of the fast pool decay rate (k) was the proportion of cell soluble components, though initial N concentration also predicted k, albeit more weakly. The size of the slow pool was best predicted by the acid non-hydrolysable fraction, which was positively correlated with melanin-associated aromatics. Nitrogen dynamics varied by necromass type, ranging from net N release to net immobilisation. The maximum quantity of N immobilised was inversely related to cell soluble contents and k, as positively related to FTIR spectra associated with cell wall polysaccharides. 4. Collectively, our results indicate that the decomposition of fungal necromass in soils can be described as having two distinct stages that are driven by different components of substrate C chemistry, with implications for rates of N availability and organic matter accumulation in soils.