Contrasting dynamics and trait controls in first-order root compared with leaf litter decomposition
Contrasting dynamics and trait controls in first-order root compared with leaf litter decomposition
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一级根与凋落物分解的动态和性状控制对比
DOI：
10.1073/pnas.1716595115
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发表时间：
2018-09
期刊：
影响因子：
--
通讯作者：
Stephan Hättenschwiler
中科院分区：
文献类型：
--
作者：
Tao Sun;Sarah Hobbie;Björn Berg;Hongguang Zhang;Qingkui Wang;Zhengwen Wang;Stephan Hättenschwiler
意义植物根系和相关真菌共生体的分解是生态系统碳循环中的一个主导过程，但与凋落叶的分解相比，特别是对于具有最高营业额的最细根来说，研究不足。在野外试验中，我们比较了最好的，最远的根和叶凋落物之间的35个共存的温带森林物种超过6年的分解。我们发现，根尖的分解速率大大低于落叶，并控制非木质素碳化合物的木质素：氮比控制落叶分解。我们的研究表明，陆地碳循环模型的基础上地上模式是不足以描述最好的植物根系的分解。分解是全球碳循环的重要组成部分，但目前的生态系统碳模型不能充分代表植物根系及其真菌对这一过程的贡献。分解动力学及其性状控制的理解是特别有限的最远端的一阶根。在这里，我们跟踪了一级根和叶凋落物分解35种不同的菌根类型在中国温带森林超过6年。一级根的分解速度（k = 0.11 ± 0.01年-1）比落叶（0.35 ± 0.02年-1）慢，在野外暴露6年后，平均仅损失初始质量的35%。与落叶相比，非木质素根C化学（非结构性碳水化合物，多酚）占82%的大种间变异的一阶根分解。外生菌根（EM）种的凋落叶分解速度比丛枝菌根（AM）种慢，而EM种的一级根在2年后从慢到快的分解速度转变为AM种的分解速度。与落叶相比，一阶根分解的根本不同的动力学和控制机制挑战了当前的生态系统C模型，最近提出的EM和AM植物之间的二分法，以及共同特征可以预测根和叶分解的想法。方面的C化学无关的木质素或氮，目前没有考虑在分解模型，控制一阶根分解，因此，目前的生态系统C动力学和模型参数化的范例需要修改。
Significance Decomposition of plant roots and associated fungal mutualists is a dominant process in ecosystem carbon cycles, yet is woefully understudied compared with decomposition of leaf litter, particularly for the finest order roots that have the highest turnover. In a field experiment, we compared decomposition of the finest, most distal roots and leaf litter among 35 cooccurring temperate forest species over 6 years. We found that decomposition rates of root tips were considerably lower than those of leaf litter and were controlled by nonlignin carbon compounds in contrast to lignin:nitrogen ratio control over leaf litter decomposition. Our study suggests that models of terrestrial carbon cycling based on aboveground patterns are inadequate to describe decomposition of the finest plant roots. Decomposition is a key component of the global carbon (C) cycle, yet current ecosystem C models do not adequately represent the contributions of plant roots and their mycorrhizae to this process. The understanding of decomposition dynamics and their control by traits is particularly limited for the most distal first-order roots. Here we followed decomposition of first-order roots and leaf litter from 35 woody plant species differing in mycorrhizal type over 6 years in a Chinese temperate forest. First-order roots decomposed more slowly (k = 0.11 ± 0.01 years−1) than did leaf litter (0.35 ± 0.02 years−1), losing only 35% of initial mass on average after 6 years of exposure in the field. In contrast to leaf litter, nonlignin root C chemistry (nonstructural carbohydrates, polyphenols) accounted for 82% of the large interspecific variation in first-order root decomposition. Leaf litter from ectomycorrhizal (EM) species decomposed more slowly than that from arbuscular mycorrhizal (AM) species, whereas first-order roots of EM species switched, after 2 years, from having slower to faster decomposition compared with those from AM species. The fundamentally different dynamics and control mechanisms of first-order root decomposition compared with those of leaf litter challenge current ecosystem C models, the recently suggested dichotomy between EM and AM plants, and the idea that common traits can predict decomposition across roots and leaves. Aspects of C chemistry unrelated to lignin or nitrogen, and not presently considered in decomposition models, controlled first-order root decomposition; thus, current paradigms of ecosystem C dynamics and model parameterization require revision.
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影响因子：
4.9
作者：
Yanmei Xiong;Pingping Fan;S. Fu;H. Zeng;Dali Guo
通讯作者：
Yanmei Xiong;Pingping Fan;S. Fu;H. Zeng;Dali Guo
DOI：
10.1111/nph.13385
发表时间：
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期刊：
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影响因子：
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作者：
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DOI：
10.1111/j.1469-8137.2011.03694.x
发表时间：
2011-07
期刊：
The New phytologist
影响因子：
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作者：
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通讯作者：
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影响因子：
9.4
作者：
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通讯作者：
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影响因子：
64.8
作者：
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通讯作者：
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