title: Ecophysiological adjustment of two Sphagnum species in response to anthropogenic nitrogen deposition.
abstract: Here, it was investigated whether Sphagnum species have adjusted their nitrogen (N) uptake in response to the anthropogenic N deposition that has drastically altered N-limited ecosystems, including peatlands, worldwide. A lawn species, Sphagnum balticum, and a hummock species, Sphagnum 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 (15)N (namely (15)NH(+)(4), (15)NO(-)(3) and the amino acids [(15)N]alanine (Ala) and [(15)N]glutamic acid (Glu)). It was found that for both species most of the N taken up was from , followed by Ala, Glu, and very small amounts from NO(-)(3). 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 NO(-)(3) uptake may make any NO(-)(3) deposited readily available to co-occurring vascular plants.
authors.affiliation: Department of Ecology and Environmental Science, Umeå University, SE-901 87 Umeå, Sweden;Evolutionary Biology Centre, Department of Plant Ecology, Uppsala University, Villavägen 14, SE-752 36 Uppsala, Sweden;Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden.
authors.forename: Magdalena M
authors.initials: MM
authors.lastname: Wiedermann
authors.affiliation: Department of Ecology and Environmental Science, Umeå University, SE-901 87 Umeå, Sweden;Evolutionary Biology Centre, Department of Plant Ecology, Uppsala University, Villavägen 14, SE-752 36 Uppsala, Sweden;Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden.
authors.forename: Urban
authors.initials: U
authors.lastname: Gunnarsson
authors.affiliation: Department of Ecology and Environmental Science, Umeå University, SE-901 87 Umeå, Sweden;Evolutionary Biology Centre, Department of Plant Ecology, Uppsala University, Villavägen 14, SE-752 36 Uppsala, Sweden;Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Ericson
authors.affiliation: Department of Ecology and Environmental Science, Umeå University, SE-901 87 Umeå, Sweden;Evolutionary Biology Centre, Department of Plant Ecology, Uppsala University, Villavägen 14, SE-752 36 Uppsala, Sweden;Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden.
authors.forename: Annika
authors.initials: A
authors.lastname: Nordin
mesh_terms: D000222:Adaptation, Physiological; D000397:Air Pollution; D000596:Amino Acids / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D012987:Soil; D012989:Soil Pollutants; D044003:Sphagnopsida / Q000378:metabolism*; D013548:Sweden
chemical_list: D000596:Amino Acids; D009566:Nitrates; D000644:Quaternary Ammonium Compounds; D012987:Soil; D012989:Soil Pollutants; D009584:Nitrogen