Effects of temperature, ultraviolet radiation and pectin methyl esterase on aerobic methane release from plant material

This study examines the effects of different irradiance types on aerobic methane (CH₄) efflux rates from terrestrial plant material. Furthermore, the role of the enzyme pectin methyl esterase (PME) on CH₄ efflux potential was also examined. Different types of plant tissue and purified pectin were incubated in glass vials with different combinations of irradiation and/or temperature. Purified dry pectin was incubated in solution, and with or without PME. Before and after incubation, the concentration of CH₄ was measured with a gas chromatograph. Rates of CH₄ emission were found to depend exponentially on temperature and linearly on UV-B irradiance. UV-B had a greater stimulating effect than UV-A, while visible light had no effect on emission rates. PME was found to substantially reduce the potential for aerobic CH₄ emissions upon demethylation of pectin.