Määttä Tiia, Malhotra Avni
Department of Geography, University of Zürich, Zürich, Switzerland.
Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA.
Glob Chang Biol. 2024 Feb;30(2):e17127. doi: 10.1111/gcb.17127.
Wetlands are the largest natural source of methane (CH ) globally. Climate and land use change are expected to alter CH emissions but current and future wetland CH budgets remain uncertain. One important predictor of wetland CH flux, plants, play an important role in providing substrates for CH -producing microbes, increasing CH consumption by oxygenating the rhizosphere, and transporting CH from soils to the atmosphere. Yet, there remain various mechanistic knowledge gaps regarding the extent to which plant root systems and their traits influence wetland CH emissions. Here, we present a novel conceptual framework of the relationships between a range of root traits and CH processes in wetlands. Based on a literature review, we propose four main CH -relevant categories of root function: gas transport, carbon substrate provision, physicochemical influences and root system architecture. Within these categories, we discuss how individual root traits influence CH production, consumption, and transport (PCT). Our findings reveal knowledge gaps concerning trait functions in physicochemical influences, and the role of mycorrhizae and temporal root dynamics in PCT. We also identify priority research needs such as integrating trait measurements from different root function categories, measuring root-CH linkages along environmental gradients, and following standardized root ecology protocols and vocabularies. Thus, our conceptual framework identifies relevant belowground plant traits that will help improve wetland CH predictions and reduce uncertainties in current and future wetland CH budgets.
湿地是全球最大的甲烷（CH₄）天然来源。气候和土地利用变化预计会改变CH₄排放，但当前及未来的湿地CH₄收支仍不确定。湿地CH₄通量的一个重要预测因子——植物，在为产CH₄微生物提供底物、通过根际充氧增加CH₄消耗以及将CH₄从土壤输送到大气方面发挥着重要作用。然而，关于植物根系及其性状在多大程度上影响湿地CH₄排放，仍存在各种机制方面的知识空白。在此，我们提出了一个关于湿地一系列根系性状与CH₄过程之间关系的全新概念框架。基于文献综述，我们提出了与CH₄相关的根系功能的四个主要类别：气体运输、碳底物供应、物理化学影响和根系结构。在这些类别中，我们讨论了个体根系性状如何影响CH₄的产生、消耗和运输（PCT）。我们的研究结果揭示了在物理化学影响方面性状功能、菌根在PCT中的作用以及根系动态变化方面的知识空白。我们还确定了优先研究需求，例如整合来自不同根系功能类别的性状测量、沿环境梯度测量根系与CH₄的联系，以及遵循标准化的根系生态学协议和术语。因此，我们的概念框架确定了相关的地下植物性状，这将有助于改进湿地CH₄预测，并减少当前及未来湿地CH₄收支的不确定性。
