Regular Article

Plant and Soil

, Volume 304, Issue 1, pp 199-208

Open Access This content is freely available online to anyone, anywhere at any time.

Amino acid uptake among wide-ranging moss species may contribute to their strong position in higher-latitude ecosystems

  • Eveline J. KrabAffiliated withDepartment of Systems Ecology, Institute of Ecological Science, Faculty of Earth and Life Sciences, VU University Amsterdam
  • , Johannes H. C. CornelissenAffiliated withDepartment of Systems Ecology, Institute of Ecological Science, Faculty of Earth and Life Sciences, VU University Amsterdam Email author 
  • , Simone I. LangAffiliated withDepartment of Systems Ecology, Institute of Ecological Science, Faculty of Earth and Life Sciences, VU University Amsterdam
  • , Richard S. P. van LogtestijnAffiliated withDepartment of Systems Ecology, Institute of Ecological Science, Faculty of Earth and Life Sciences, VU University Amsterdam

Abstract

Plants that can take up amino acids directly from the soil solution may have a competitive advantage in ecosystems where inorganic nitrogen sources are scarce. We hypothesized that diverse mosses in cold, N-stressed ecosystems share this ability. We experimentally tested 11 sub-arctic Swedish moss species of wide-ranging taxa and growth form for their ability to take up double labelled (15N and 13C) glycine and aspartic acid in a laboratory setup as well as in a realistic field setting. All species were able to take up amino acids injected into the soil solution to some extent, although field uptake was marginal to absent for the endohydric Polytrichum commune. The 11 moss species on average took up 36 ± 5% of the injected glycine and 18 ± 2% of the aspartic acid in the lab experiment. Field uptake of both glycine (24 ± 5%) and aspartic acid (10 ± 2%) was lower than in the lab. Overall differences in uptake amongst species appeared to be positively associated with habitat wetness and/or turf density among different Sphagnum species and among non-Sphagnum species, respectively. Species from habitats of lower inorganic N availability, as indicated tentatively by lower tissue N concentrations, showed relatively strong amino acid uptake, but this was only significant for the field uptake among non-Sphagnum mosses. Further experiments are needed to test for consistent differences in amino acid uptake capacity among species and functional groups as determined by their functional traits, and to test how the affinity of cold-biome mosses for amino acids compares to that for ammonium or nitrate. Still, our results support the view that widespread moss species in cold, N-stressed ecosystems may derive a significant proportion of their nitrogen demand from free amino acids. This might give them a competitive advantage over plants that depend strongly on inorganic N sources.

Keywords

Aspartic acid Bryophyte Glycine Isotope labeling Nitrogen availability Sub-arctic