Plant-mediated Methane Transport And Methane Emissions From Phragmites Australis Marsh In Minjiang River Estuary

Plant-mediated methane transport is one of the important paths of methane emission. In a Phragmites australis marsh in the Shanyutan wetland of the Minjiang river estuary area, the static chamber/self-designed hanging chamber-gas chromatograph technique was applied to investigate the diurnal patterns and seasonal variations of methane emission from P. australis marsh and methane transport capacity of P. australis plant individuals simultaneously.The results showed that methane emissions were higher in spring and summer than that infall and winter, which were remarkably affected by soil salinity. However, dial variation, with grater value in daytime, was not controlled by any environmental factors. Comparably, the methane transport capacity had no distinct seasonal variations and diel variations patterns. Result also indicated the bottom part of reed stem was the primarily part of release methane when plant-mediated transport occurred. Methane concentratons in pith cavities of reed culms were measured and the results demonstrated methane concentration was significantly higher in those parts close to soil surface, compared with those in cavities next to apex. A shading experiment was also conducted, the result was that consequence elucidated methane transport capacity was decreased by increasing photosynthetically active radiation.