This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Calhoun, A. Articles by King, G. M. Search for Related Content PubMed PubMed Citation Articles by Calhoun, A. Articles by King, G. M. Agricola Articles by Calhoun, A. Articles by King, G. M.

 Previous Article  |  Next Article 

Appl. Environ. Microbiol., Aug 1997, 3051-3058, Vol 63, No. 8
Copyright © 1997, American Society for Microbiology

Regulation of Root-Associated Methanotrophy by Oxygen Availability in the Rhizosphere of Two Aquatic Macrophytes

A Calhoun and GM King
Darling Marine Center, University of Maine, Walpole, Maine 04573

The relative importance of oxygen for root-associated methanotrophy was examined by using sediment-free, intact freshwater marsh plants (Pontederia cordata and Sparganium eurycarpum) incubated in split chambers. The root medium contained approximately 100 (mu)M methane. Methane oxidation was calculated from the difference between methane loss from chambers in the presence and absence of 1 mM 1-allyl-2-thiourea, a methanotrophic inhibitor. When the root medium was oxic, methane oxidation accounted for 88 and 63% of the total methane depletion for S. eurycarpum and P. cordata, respectively; the remainder represented diffusional loss to the atmosphere via roots, stems, and leaves. Under suboxic conditions, methane oxidation was not detectable for S. eurycarpum but accounted for 68% of total methane depletion for P. cordata. The introduction of a biological oxygen sink, Pseudomonas aeruginosa, resulted in complete loss of methane oxidation in S. eurycarpum chambers under oxic conditions, while methane consumption continued (51.6% of total methane depletion) in P. cordata chambers. The differences between plant species were consistent with their relative ability to oxygenate their rhizospheres: during a suboxic incubation, dissolved oxygen decreased by 19% in S. eurycarpum chambers but increased by 232% for P. cordata. An in situ comparison also revealed greater methanotrophic activity for P. cordata than S. eurycarpum.

This article has been cited by other articles:

• van Bodegom, P., Stams, F., Mollema, L., Boeke, S., Leffelaar, P. (2001). Methane Oxidation and the Competition for Oxygen in the Rice Rhizosphere. Appl. Environ. Microbiol. 67: 3586-3597 [Abstract] [Full Text]  
• King, G. M., Garey, M. A. (1999). Ferric Iron Reduction by Bacteria Associated with the Roots of Freshwater and Marine Macrophytes. Appl. Environ. Microbiol. 65: 4393-4398 [Abstract] [Full Text]  
• Emerson, D., Weiss, J. V., Megonigal, J. P. (1999). Iron-Oxidizing Bacteria Are Associated with Ferric Hydroxide Precipitates (Fe-Plaque) on the Roots of Wetland Plants. Appl. Environ. Microbiol. 65: 2758-2761 [Abstract] [Full Text]  
• Rich, J. J., King, G. M. (1998). Carbon Monoxide Oxidation by Bacteria Associated with the Roots of Freshwater Macrophytes. Appl. Environ. Microbiol. 64: 4939-4943 [Abstract] [Full Text]  
• Calhoun, A., King, G. M. (1998). Characterization of Root-Associated Methanotrophs from Three Freshwater Macrophytes: Pontederia cordata, Sparganium eurycarpum, and Sagittaria latifolia. Appl. Environ. Microbiol. 64: 1099-1105 [Abstract] [Full Text]