Vascular plants are important in the wetland methane cycle, but their effect on production, oxidation, and transport has high uncertainty, limiting our ability to predict emissions. In a permafrost‐thaw bog in Interior Alaska, we used plant manipulation treatments, field‐deployed planar optical oxygen sensors, direct measurements of methane oxidation, and microbial DNA analyses to disentangle mechanisms by which vascular vegetation affect methane emissions. Vegetation operated on top of baseline methane emissions, which varied with proximity to the thawing permafrost margin. Emissions from vegetated plots increased over the season, resulting in cumulative seasonal methane emissions that were 4.1–5.2 g m⁻² season⁻¹ greater than unvegetated plots. Mass balance calculations signify these greater emissions were due to increased methane production (3.0–3.5 g m⁻² season⁻¹) and decreased methane oxidation (1.1–1.6 g m⁻² season⁻¹). Minimal oxidation occurred along the plant‐transport pathway, and oxidation was suppressed outside the plant pathway. Our data indicate suppression of methane oxidation was stimulated by root exudates fueling competition among microbes for electron acceptors. This contention is supported by the fact that methane oxidation and relative abundance of methanotrophs decreased over the season in the presence of vegetation, but methane oxidation remained steady in unvegetated treatments; oxygen was not detected around plant roots but was detected around silicone tubes mimicking aerenchyma; and oxygen injection experiments suggested that oxygen consumption was faster in the presence of vascular vegetation. Root exudates are known to fuel methane production, and our work provides evidence they also decrease methane oxidation.

中文翻译：

---

探寻热溶岩沼泽中植物介导的甲烷排放和氧化的根源

血管植物在湿地甲烷循环中很重要，但是它们对生产，氧化和运输的影响具有很高的不确定性，限制了我们预测排放的能力。在阿拉斯加内陆的一个冻土融化沼泽中，我们使用了植物处理方法，现场部署的平面光学氧气传感器，甲烷氧化的直接测量方法以及微生物DNA分析，以弄清血管植被影响甲烷排放的机制。植被是在基线甲烷排放量之上运行的，甲烷排放量随着接近融化的多年冻土边缘而变化。整个季节，植被地的排放量增加，导致累积的季节性甲烷排放量为4.1–5.2 g m ^-2季节^-1大于无植被的地块。质量平衡计算表明，这些较大的排放量是由于甲烷产量增加（3.0–3.5 g m ^-2时令^-1）和甲烷氧化减少（1.1–1.6 g m ^-2时令^{−1）引起的}）。沿着植物运输途径的氧化最小，而在植物途径外的氧化被抑制。我们的数据表明甲烷氧化的抑制是由根系分泌物刺激的，从而加剧了微生物之间对电子受体的竞争。在存在植被的季节中，甲烷氧化和甲烷氧化菌的相对丰度降低，但在无植被的处理中甲烷氧化保持稳定，这一论据得到了支持。在植物根部周围未检测到氧气，但在模拟气孔的硅胶管周围检测到氧气；氧气注射实验表明，在有血管植物的情况下耗氧速度更快。众所周知，根系分泌物可促进甲烷的产生，我们的工作提供了证据，它们也可减少甲烷的氧化。