Substrate stoichiometry determines nitrogen fixation throughout succession in southern Chinese forests
Substrate stoichiometry determines nitrogen fixation throughout succession in southern Chinese forests
复制标题
底物化学计量决定中国南方森林演替过程中的固氮作用
DOI：
10.1111/ele.13437
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发表时间：
2020
期刊：
影响因子：
8.8
通讯作者：
Jiangming Mo
中科院分区：
文献类型：
--
作者：
Mianhai Zheng;Hao Chen;Dejun Li;Yiqi Luo;Jiangming Mo
传统观点认为，生物固氮作用通常在演替的早期或中期达到峰值，并在整个演替过程中下降，这是基于土壤氮素丰富和/或磷素缺乏对固氮菌不利的假设。然而，这一观点并不支持这样的观察结果，即尽管存在富氮和/或磷限制土壤，但在许多古老的森林中，固氮菌仍然可以保持活性。在这里，我们发现在土壤中，森林地面，苔藓在整个三个演替森林和沿着六个年龄梯度的森林在中国南方的固定率意想不到的增加。我们进一步发现，在氮固定的变化是由基板碳（C）：N和C：（N：P）的化学计量比，而不是由基板N或P。我们的研究结果突出了生态化学计量的效用，照亮耦合森林演替和N循环的机制。
The traditional view holds that biological nitrogen (N) fixation often peaks in early‐ or mid‐successional ecosystems and declines throughout succession based on the hypothesis that soil N richness and/or phosphorus (P) depletion become disadvantageous to N fixers. This view, however, fails to support the observation that N fixers can remain active in many old‐growth forests despite the presence of N‐rich and/or P‐limiting soils. Here, we found unexpected increases in N fixation rates in the soil, forest floor, and moss throughout three successional forests and along six age‐gradient forests in southern China. We further found that the variation in N fixation was controlled by substrate carbon(C) : N and C : (N : P) stoichiometry rather than by substrate N or P. Our findings highlight the utility of ecological stoichiometry in illuminating the mechanisms that couple forest succession and N cycling.