Missing methane emissions from leaves of terrestrial plants

Abstract

Abstract The controversial claim that attached leaves of terrestrial plants emit CH 4 aerobically remains to be corroborated. Here, we report CH 4 fluxes and CO 2 exchange rates for leaves of the C 4 species Zea mays using a high‐accuracy traceable online analytical system. In contrast to earlier results for Z. mays , our measurements provide no evidence for substantial aerobic CH 4 emissions from photosynthesizing leaves illuminated with photosynthetically active radiation ( λ =400–700 nm), or from dark‐respiring leaves. Preliminary measurements with the same system indicated a similar lack of aerobic CH 4 emissions in the light or dark from leaves of the C 3 species Nicotiana tabacum . These findings are supported by independent high‐precision 13 C‐labeling studies that also failed to confirm substantial aerobic CH 4 emissions from plants. Nevertheless, we are not able to exclude the possibility that CH 4 emissions from plants may be linked to nonenzymatic processes with an action spectrum lying outside the wavelength range for photosynthesis.