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 Aumen, N. G. Articles by Gregory, S. V. Search for Related Content PubMed PubMed Citation Articles by Aumen, N. G. Articles by Gregory, S. V. Agricola Articles by Aumen, N. G. Articles by Gregory, S. V.

 Previous Article  |  Next Article 

Appl Environ Microbiol. 1985 May; 49(5): 1113-1118
Copyright © 1985, American Society for Microbiology. All Rights Reserved.

Impact of Nitrogen and Phosphorus on [¹⁴C]Lignocellulose Decomposition by Stream Wood Microflora

Nicholas G. Aumen^,*, Peter J. Bottomley and Stan V. Gregory

¹ Departments of Microbiology, Soil Science, ² and Fisheries and Wildlife, ³ Oregon State University, Corvallis, Oregon 97331-3804

ABSTRACT

Nutritional and physical factors affecting the decomposition of [¹⁴C]lignocellulose prepared from Douglas fir (Pseudotsuga menziesii) were examined by incubating the labeled substrate with homogenized surface wood scrapings obtained from a Douglas fir log in a Pacific Northwest stream. Incubations were conducted in distilled water, in stream water collected from four different sources, or in a defined mineral salts solution with or without supplemental N (KNO₃). Decomposition rates of [¹⁴C]lignocellulose, as measured by ¹⁴CO₂ evolution, were greater in each of the four filter-sterilized sources of stream water than in distilled water alone. Decomposition experiments conducted in stream water media with the addition of defined mineral salts demonstrated that [¹⁴C]cellulose decomposition was stimulated 50% by the addition of either KNO₃ or KH₂PO₄/K₂HPO₄ and further enhanced (167%) by a combination of both. In contrast, [¹⁴C]lignin decomposition was stimulated (65%) only by the addition of both N and P. Decomposition of [¹⁴C]lignocellulose was greatest when supplemental KNO₃ was supplied in concentrations of at least 10.0 mg of N liter^–1 but not increased further by higher concentrations. The decomposition of [¹⁴C]lignocellulose increased as the incubation temperature was raised and NO₃^–1-N supplementation further increased these rates between three-and sevenfold over the range of temperatures examined (5 to 22°C). Accumulation of NH₄⁺ (2 to 4 mg of N liter^–1) was always observed in culture filtrates of incubations which had been supplemented with KNO₃, the quantity being independent of NO₃^– concentrations 10 mg of N liter^–1. The role of supplemental NO₃^– in the decomposition of [¹⁴C]lignocellulose is discussed in relation to wood decomposition and the low concentrations of N found in stream ecosystems of the Pacific Northwest.

^* Corresponding author.

Present address: Department of Biology, The University of Mississippi, University, MS 38677.

Oregon State University Agricultural Experiment Station Technical Paper no. 7376.

This article has been cited by other articles:

• Qualls, R. G., Richardson, C. J. (2000). Phosphorus Enrichment Affects Litter Decomposition, Immobilization, and Soil Microbial Phosphorus in Wetland Mesocosms. Soil Sci. 64: 799-808 [Abstract] [Full Text]