Insights into the mechanism of diurnal variations in methane emission from the stem surfaces of <i>Alnus japonica</i>
Insights into the mechanism of diurnal variations in methane emission from the stem surfaces of <i>Alnus japonica</i>
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赤杨茎表面甲烷排放日变化机制研究
DOI：
10.1111/nph.18283
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发表时间：
2022
期刊：
影响因子：
9.4
通讯作者：
Kosugi Yoshiko
中科院分区：
文献类型：
--
作者：
Takahashi Kenshi;Sakabe Ayaka;Azuma Wakana A.;Itoh Masayuki;Imai Tomoya;Matsumura Yasuki;Tateishi Makiko;Kosugi Yoshiko
最近的研究表明，在某些环境中，树干会释放甲烷（CH4）。本研究探讨了河岸湿地赤杨树干表面CH4排放的机制。全年监测茎CH4排放速率和汁液通量，并调查细根解剖结构。CH4排放速率使用密闭室方法进行估计。使用Granier型热耗散探针测量树液通量。利用光学显微镜和低温扫描电子显微镜研究了根的解剖结构，结果表明，在多叶季节，CH4排放量呈现出日变化的特征，并与根液流的日变化一致。我们提出了一个模型，其中干CH4排放涉及至少两个过程：一个液流依赖的组件负责的昼夜变化，和一个液流独立的组件负责的背景连续。这两个过程的贡献率随季节变化而变化，背景连续统可能是由CH4气体从根部向上部树干扩散输送的结果。根系解剖分析表明，皮层细胞间隙和细根中空木质部细胞可作为CH4气体运输的通道。
Recent studies have suggested that in certain environments, tree stems emit methane (CH4). This study explored the mechanism of CH4emission from the stem surfaces ofAlnus japonicain a riparian wetland. Stem CH4emission rates and sap flux were monitored year‐round, and fine‐root anatomy was investigated.CH4emission rates were estimated using a closed‐chamber method. Sap flux was measured using Granier‐type thermal dissipation probes. Root anatomy was studied using both optical and cryo‐scanning electron microscopy.CH4emissions during the leafy season exhibited a diurnally changing component superimposed upon an underlying continuum in which the diurnal variation was in phase with sap flux. We propose a model in which stem CH4emission involves at least two processes: a sap flux‐dependent component responsible for the diurnal changes, and a sap flux‐independent component responsible for the background continuum. The contribution ratios of the two processes are season‐dependent.The background continuum possibly resulted from the diffusive transport of gaseous CH4from the roots to the upper trunk. Root anatomy analysis indicated that the intercellular space of the cortex and empty xylem cells in fine roots could serve as a passageway for transport of gaseous CH4.