Zero methane emission bogs: extreme rhizosphere oxygenation by cushion plants in Patagonia
Zero methane emission bogs: extreme rhizosphere oxygenation by cushion plants in Patagonia
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DOI：
10.1111/j.1469-8137.2010.03604.x
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发表时间：
2011-01-01
期刊：
影响因子：
9.4
通讯作者：
Smolders, Alfons J. P.
中科院分区：
文献类型：
--
作者：
Fritz, Christian;Pancotto, Veronica A.;Smolders, Alfons J. P.
维管湿地植物可以通过产生根系分泌物和易降解的凋落物，以及通过通气组织提供低阻力扩散途径来显著增加甲烷排放。然而，模型研究表明，维管植物可以减少甲烷排放时，土壤需氧量超过了从根释放的氧气。在这里，我们测试了这些条件是否发生在沼泽为主的垫plants.Root-methane相互作用进行了研究，通过比较甲烷排放量，股票和氧气供应量的深度配置文件下的草坪垫植物或泥炭藓在Patagonia.Cushion植物，Astelia pumila和Donatia fascicularis，形成了广泛的根系深度可达120厘米。寒冷的土壤（< 10摄氏度）和高度分解的泥炭导致低微生物活性和氧气消耗。在垫植物草坪，高土壤氧符合高根密度，但甲烷排放量是不存在的。在泥炭藓草坪中，甲烷排放量很大。高浓度的甲烷只存在于没有垫状植物根系的土壤中。巴塔哥尼亚沼泽植被中的首次甲烷研究显示，甲烷排放量低于预期。垫状植物通过对土壤和甲烷的彻底氧化，在生态系统尺度上减少甲烷的排放。
P>Vascular wetland plants may substantially increase methane emissions by producing root exudates and easily degradable litter, and by providing a low-resistance diffusion pathway via their aerenchyma. However, model studies have indicated that vascular plants can reduce methane emission when soil oxygen demand is exceeded by oxygen released from roots. Here, we tested whether these conditions occur in bogs dominated by cushion plants.Root-methane interactions were studied by comparing methane emissions, stock and oxygen availability in depth profiles below lawns of either cushion plants or Sphagnum mosses in Patagonia.Cushion plants, Astelia pumila and Donatia fascicularis, formed extensive root systems up to 120 cm in depth. The cold soil (< 10 degrees C) and highly decomposed peat resulted in low microbial activity and oxygen consumption. In cushion plant lawns, high soil oxygen coincided with high root densities, but methane emissions were absent. In Sphagnum lawns, methane emissions were substantial. High methane concentrations were only found in soils without cushion plant roots.This first methane study in Patagonian bog vegetation reveals lower emissions than expected. We conclude that cushion plants are capable of reducing methane emission on an ecosystem scale by thorough soil and methane oxidation.