title: Nonmicrobial aerobic methane emission from poplar shoot cultures under low-light conditions.
abstract: The aerobic formation of methane in plants has been reported previously, but has been questioned by a number of researchers. Recently, isotopic evidence demonstrated that ultraviolet irradiation and heating lead to photochemical or thermal aerobic methane formation mainly from plant pectin in the absence of microbial methane production. However, the origin of aerobic methane formation from plant material observed under low temperature and low-light/dark conditions is still unclear. Here we show that Grey poplar (Populus × canescens, syn. Populus tremula × Populus alba) plants derived from cell cultures under sterile conditions released 13C-labeled methane under low-light conditions after feeding the plants with 13CO2. Molecular biological analysis proved the absence of any microbial contamination with known methanogenic microorganisms and ruled out the possibility that methane emission from our poplar shoot cultures under aerobic low-light/dark and ambient temperature conditions could be of microbial origin. The CH4 release rates in our experiment were in the range of 0.16-0.7 ng g-1 DW h-1, adding evidence to the growing opinion that the quantitative role of aerobic methane emissions from plants in the global methane budget, at least from cold temperate or boreal regions, is only of minor importance.
authors.affiliation: Research Centre Karlsruhe, Institute of Meteorology and Climate Research (IMK-IFU), Kreuzeckbahnstrasse 19, D-82467 Garmisch-Partenkirchen, Germany.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Brüggemann
authors.affiliation: Research Centre Karlsruhe, Institute of Meteorology and Climate Research (IMK-IFU), Kreuzeckbahnstrasse 19, D-82467 Garmisch-Partenkirchen, Germany.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Meier
authors.affiliation: Research Centre Karlsruhe, Institute of Meteorology and Climate Research (IMK-IFU), Kreuzeckbahnstrasse 19, D-82467 Garmisch-Partenkirchen, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Steigner
authors.affiliation: Research Centre Karlsruhe, Institute of Meteorology and Climate Research (IMK-IFU), Kreuzeckbahnstrasse 19, D-82467 Garmisch-Partenkirchen, Germany.
authors.forename: Ina
authors.initials: I
authors.lastname: Zimmer
authors.affiliation: Research Centre Karlsruhe, Institute of Meteorology and Climate Research (IMK-IFU), Kreuzeckbahnstrasse 19, D-82467 Garmisch-Partenkirchen, Germany.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Louis
authors.affiliation: Research Centre Karlsruhe, Institute of Meteorology and Climate Research (IMK-IFU), Kreuzeckbahnstrasse 19, D-82467 Garmisch-Partenkirchen, Germany.
authors.forename: Jörg-Peter
authors.initials: JP
authors.lastname: Schnitzler
mesh_terms: D000332:Aerobiosis / Q000528:radiation effects; D001419:Bacteria / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D002247:Carbon Isotopes; D018744:DNA, Plant / Q000235:genetics; D004587:Electrophoresis, Agar Gel; D007553:Isotope Labeling; D008027:Light; D008697:Methane / Q000378:metabolism*; D010788:Photosynthesis / Q000528:radiation effects; D018520:Plant Shoots / Q000378:metabolism* / Q000528:radiation effects; D016133:Polymerase Chain Reaction; D032107:Populus / Q000378:metabolism* / Q000528:radiation effects*; D046509:Tissue Culture Techniques
chemical_list: D002247:Carbon Isotopes; D018744:DNA, Plant; D002245:Carbon Dioxide; D008697:Methane