Extracellular acid phosphatase activities in Eriophorum vaginatum tussocks: A modeling synthesis
- Texas Tech Univ., Lubbock (United States)
- Virginia Polytechnic Inst. and State Univ., Blacksburg (United States)
- Clarkson Univ., Potsdan, NY (United States)
- San Diego State Univ., CA (United States)
Analyses of Eriophorum vaginatum tussocks provided mass and kinetic parameters for a Michaelis-Menten model of phosphatase activities in Alaskan tussock tundra. This model was used to simulate the temporal patterns of phosphatase activities, given a 90-d thawing season and organic phosphorus concentrations of 30 [mu]M in the first and last 10-d intervals; 15 [mu]M at other times. Results indicated that about 28% of the total annual tussock activity (155 mg P released) occurred during the brief period of high substrate availability in autumn; little occurred in spring because most of the tussock was frozen and live root mass was low. Phosphatases associated with living roots of E. vaginatum were responsible for about 4% of the total activity in tussocks (ca. 6 mg P), which is almost twice the annual plant demand (ca. 3.5 mg). These results suggest that (1) E. vaginatum may obtain much of its phosphorus requirement from the activities of root surface phosphatases, and (2) the timing of maximum plant phosphorus uptake (late in year) and growth (early in year) are asynchronous, i.e., E. vaginatum integrates nutrient availabilities across years. 41 refs., 2 figs., 1 tab.
- DOE Contract Number:
- FG03-84ER60250
- OSTI ID:
- 6653661
- Journal Information:
- Arctic and Alpine Research (Boulder, Colorado); (United States), Vol. 25:1; ISSN 0004-0851
- Country of Publication:
- United States
- Language:
- English
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