@article{mbs:/content/journal/micro/10.1099/00221287-123-2-313, author = "Schink, Bernhard and Ward, James C. and Zeikus, J. G.", title = "Microbiology of Wetwood: Role of Anaerobic Bacterial Populations in Living Trees", journal= "Microbiology", year = "1981", volume = "123", number = "2", pages = "313-322", doi = "https://doi.org/10.1099/00221287-123-2-313", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-123-2-313", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", abstract = "Anaerobic bacterial activity was detected in wetwoods of living Populus deltoides Bartr. and Ulmus americana L. by analysis of chemical, structural and microbiological parameters. Wetwood contained significant quantities (⩾1·0 mm) of bacterial fermentation products including acetate, butyrate, propionate, ethanol, isobutyrate, isopropanol and methane. Oxygen was not detected in wetwood and the ammonia concentration was low (⩽5 μm). Scanning electron microscopy showed that vessel-to-ray pit membranes of wetwood xylem tissue were almost completely destroyed and were associated with dense bacterial populations. Bacterial nitrogenase activity was detected in wetwood samples. Anaerobic bacterial populations in wetwood were as large or larger than populations capable of aerobic growth, and contained (in total cell numbers g−1) heterotrophic (106 to 107), nitrogen-fixing (105 to 106) and methanogenic (103 to 104) species. Anaerobic bacteria were 104 times more numerous in wetwood than in sapwood. Thirteen strains of anaerobic heterotrophic bacteria were isolated and characterized from wetwood and included Clostridium, Bacteroides, Erwinia, Edwardsiella, Klebsiella and Lactobacillus species. Only two strains, a pectindegrading Clostridium species and a nitrogen-fixing Erwinia species, were prevalent in wetwoods of all the trees examined. The metabolic features of the strains examined correlated to the described chemical, structural and microbiological properties of wetwood.", }