Microbial methane production is affected by secondary metabolites in the heartwood of living trees in upland forests

• Published in: Trees (Berlin, West) West), 2020-02, Vol.34 (1), p.243-254
• Main Authors: Li, Huan-Long, Zhang, Xi-Mei, Deng, Feng-Dan, Han, Xing-Guo, Xiao, Chun-Wang, Han, Shi-Jie, Wang, Zhi-Ping
• Format: Article
• Language: English
• Subjects: Acetone; Agriculture; Antibiotics; Archaea; Atmospheric chemistry; Biomedical and Life Sciences; Carbohydrates; Climate change; Emissions; Ethanol; Forestry; Forests; Gene sequencing; Global warming; Greenhouse effect; Greenhouse gases; Life Sciences; Metabolites; Methane; Methanogenic archaea; Methanogenic bacteria; Microorganisms; Organic chemistry; Original Article; Phenolic compounds; Phenols; Plant Anatomy/Development; Plant Pathology; Plant Physiology; Plant Sciences; Secondary metabolites; Trees
• ISSN: 0931-1890; 1432-2285
• DOI: 10.1007/s00468-019-01914-6

Key message This paper shows that CH 4 produced in the heartwood of living trees in upland forests is of microbial origin, and that microbial CH 4 production may be suppressed in the heartwood with more phenolic compounds than carbohydrates. Methane (CH 4 ) is a potent greenhouse gas that exerts large effects on atmospheric chemistry and the global warming. Living trees in upland forests might contribute to the global CH 4 emissions but the contribution is poorly understood and the mechanisms of CH 4 production in their heartwood are not completely clear. Using gene sequencing and a series of laboratory incubations, this study addressed whether CH 4 produced in the heartwood of living trees in upland forests is microbial in origin and how the CH 4 production is affected by secondary metabolites. Both the response of CH 4 production to temperatures and the presence of methanogenic archaea indicate that the CH 4 produced in heartwood was microbial in origin. Methanobacterium was the dominant methanogens in the heartwood of Populus canadensis which had high concentrations of CH 4 , and was absent from the heartwood of Pinus tabuliformis and Salix matsudana which produced negligible or very low CH 4 . Water- and ethanol-soluble extractives enhanced microbial CH 4 production in heartwood incubations but acetone-soluble extractives inhibited the production. Since acetone-soluble extractives inhibited the production of microbial CH 4 , it is assumed that the CH 4 production may be suppressed from heartwood with phenolic compounds that act as an antibiotic for methanogenic archaea in most living trees in upland forests. The inhibitory effects of secondary metabolites on microbial CH 4 production in heartwood reduce the CH 4 emissions from the stems of living trees in upland forests.