School of GeoSciences, The University of Edinburgh, Crew Building, West Mains Road, Edinburgh EH9 3JN, UK.
National Center for Atmospheric Research (NCAR), Atmospheric Chemistry Division, PO Box 3000, Boulder, CO 80305, USA.
New Phytol. 2010 Jul;187(2):417-425. doi: 10.1111/j.1469-8137.2010.03259.x. Epub 2010 Apr 28.
*Several studies have reported in situ methane (CH(4)) emissions from vegetation foliage, but there remains considerable debate about its significance as a global source. Here, we report a study that evaluates the role of ultraviolet (UV) radiation-driven CH(4) emissions from foliar pectin as a global CH(4) source. *We combine a relationship for spectrally weighted CH(4) production from pectin with a global UV irradiation climatology model, satellite-derived leaf area index (LAI) and air temperature data to estimate the potential global CH(4) emissions from vegetation foliage. *Our results suggest that global foliar CH(4) emissions from UV-irradiated pectin could account for 0.2-1.0 Tg yr(-1), of which 60% is from tropical latitudes, corresponding to < 0.2% of total CH(4) sources. *Our estimate is one to two orders of magnitude lower than previous estimates of global foliar CH(4) emissions. Recent studies have reported that pectin is not the only molecular source of UV-driven CH(4) emissions and that other environmental stresses may also generate CH(4). Consequently, further evaluation of such mechanisms of CH(4) generation is needed to confirm the contribution of foliage to the global CH(4) budget.
*多项研究报道了植被叶片原位产生的甲烷（CH(4)），但关于其作为全球源的重要性仍存在较大争议。*在这里，我们报告了一项评估紫外（UV）辐射驱动果胶产生的 CH(4)作为全球 CH(4)源的作用的研究。*我们将果胶的光谱加权 CH(4)生成关系与全球 UV 辐照度气候模型、卫星衍生的叶面积指数（LAI）和空气温度数据相结合，以估算植被叶片的潜在全球 CH(4)排放。*我们的结果表明，全球因 UV 辐照果胶而产生的叶 CH(4)排放可能占 0.2-1.0 Tg yr(-1)，其中 60%来自热带纬度，对应于总 CH(4)源的 <0.2%。我们的估计值比先前全球叶 CH(4)排放的估计值低一到两个数量级。最近的研究报告称，果胶不是唯一由 UV 驱动的 CH(4)排放的分子源，其他环境压力也可能产生 CH(4)。因此，需要进一步评估这种 CH(4)生成机制，以确认叶片对全球 CH(4)预算的贡献。
