Ecophysiological adjustment of two Sphagnum species in response to anthropogenic nitrogen deposition
2009 (English)In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 181, no 1, 208-217 p.Article in journal (Refereed) Published
We asked whether Sphagnum species have adjusted their N uptake in response to the anthropogenic N deposition that has drastically altered N-limited ecosystems, including peatlands, worldwide. A lawn species, S. balticum, and a hummock species, S. fuscum, were collected from three peatlands along a gradient of N deposition (2, 8 and 12 kg N ha-1 yr-1). The mosses were subjected to solutions containing a mixture of four N forms. In each solution one of these N forms was labeled with 15N (viz. 15NH4+, 15NO3- and the amino acids [15N]alanine (ALA) and [15N]glutamic acid (GLU)). We found for both species that the majority of the N taken up was from NH4+, followed by ALA, GLU, and very small amounts of NO3-. At the highest N deposition site N uptake was reduced, but this did not prevent N accumulation as free amino acids in the Sphagnum tissues. The reduced N uptake may have been genetically selected for under the relatively short period with elevated N exposure from anthropogenic sources, or may have been the result of plasticity in the Sphagnum physiological response. The negligible Sphagnum NO3- uptake may make any NO3- deposited readily available to co-occurring vascular plants.
Place, publisher, year, edition, pages
2009. Vol. 181, no 1, 208-217 p.
IdentifiersURN: urn:nbn:se:umu:diva-23284DOI: 10.1111/j.1469-8137.2008.02628.xOAI: oai:DiVA.org:umu-23284DiVA: diva2:222608