Wetlands host anaerobic microbes which convert organic carbon into methane (CH4), a powerful greenhouse gas. Wetland plants can influence which carbon compounds are available for microbial processing by exuding freshly fixed carbon from their roots. Exudation of carbon from plant roots can trigger microbial priming: the process of new carbon stimulating the microbial community into processing more soil carbon than they otherwise would have. This study utilized high resolution Fourier transform ion cyclotron mass spectrometry (FT-ICR-MS) analysis to probe the composition of soil organic compounds from the rhizosphere of Carex aquatillis, a common wetland sedge, which is known to have stimulated microbial priming within peat soil. The goal was to identify what types of molecules were created or lost during microbial priming in the wetland rhizosphere and thus advance mechanistic understanding of the process. FT-ICR-MS analysis demonstrated that more microbial transformations of carbon occurred among water-soluble compounds than among hydrophobic compounds, but that some hydrophobic compounds were processed. Crucially for understanding microbial priming, the root exudates triggered increased processing of high molecular weight molecules regardless of nutrient content but processed low molecular weight compounds only if they contained nitrogen or sulfur, essential nutrients for plant growth. The importance of sulfur in determining molecular utilization is noteworthy because priming literature typically focuses on nitrogen-mining. The fact that some molecules were processed and others were not is evidence for a selective priming effect in which some carbon compounds with specific properties are used at an increased rate, while others are left unaltered.

中文翻译：

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营养物质对沼泽根际微生物启动的重要性

湿地拥有厌氧微生物，可将有机碳转化为强大的温室气体甲烷 (CH4)。湿地植物可以通过从根部渗出新鲜固定的碳来影响哪些碳化合物可用于微生物加工。从植物根部渗出的碳会触发微生物启动：新碳的过程刺激微生物群落处理比其他情况下更多的土壤碳。这项研究利用高分辨率傅里叶变换离子回旋质谱 (FT-ICR-MS) 分析来探测来自 Carex aquatillis 根际的土壤有机化合物的组成，这是一种常见的湿地莎草，已知它刺激了泥炭土壤中的微生物引发. 目标是确定在湿地根际微生物引发过程中产生或丢失了哪些类型的分子，从而促进对该过程的机械理解。FT-ICR-MS 分析表明，与疏水化合物相比，水溶性化合物之间发生了更多的碳微生物转化，但对一些疏水化合物进行了处理。对于理解微生物引发至关重要，无论营养成分如何，根系分泌物都会引发高分子量分子的加工增加，但只有当低分子量化合物含有氮或硫（植物生长的必需营养素）时，才会加工低分子量化合物。硫在确定分子利用方面的重要性值得注意，因为启动文献通常侧重于氮开采。