Tundra plant uptake of amino acid and NH{sub 4}{sup +} nitrogen in situ: Plants compete well for amino acid N{sup 1}
- Univ. of Alaska, Fairbanks, AK (United States)
- Univ. of California, Berkeley, CA (United States)
Traditional models of nutrient cycling assume that soil microorganisms must decompose organic matter, releasing inorganic N, to make N available to plants. Several lines of evidence have raised doubts about this assumption in arctic tundra, but no firm evidence existed. Here we demonstrate that Eriophorum vaginatum and Carex aquatilis, two tundra sedges, compete well for glycine and asparate N relative to NH{sub 4}{sup +} in situ. At relatively high concentrations (25 {mu}g N/g soil), during the peak of the season, E. vaginatum took up amino acid N more rapidly than NH{sub 4}{sup +}, while later in the season and at lower concentrations (2-4 {mu}g N/g soil) both E. vaginatum and C. aqualtilis took up glycine N and NH{sub 4}{sup +} at similar rates. These results are incompatible with a simple mechanism of amino acid mineralization followed by plant uptake of the released N. These results indicate that these tundra plants have active mechanisms for enhancing their access to amino acid N in situ. 18 refs., 4 tabs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 482556
- Journal Information:
- Ecology, Vol. 77, Issue 7; Other Information: PBD: Oct 1996
- Country of Publication:
- United States
- Language:
- English
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