We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
TRANSIENT AMMONIUM UPTAKE IN THE MACROALGA <em>ULVA LACTUCA</em> (CHLOROPHYTA): NATURE, REGULATION, AND THE CONSEQUENCES FOR CHOICE OF MEASURING TECHNIQUE.
- Authors
Pedersen, Morten Foldager
- Abstract
The nature of transient ammonium uptake by the macroalga Ulva lactuca L. was studied from the depletion of ammonium after single additions of ammonium to bacth cultures. The experiments were carried out by the application of tow different experimental setups: the "multiple flask" and the "perturbation" techniques. Uptake rate was nonlinear with time, and three distinct, succeeding phases of uptake were identified: 1) "surge" uptake, i.e. transiently enhanced uptake that lasted for a few hours only, followed by 2) "internally" controlled uptake, a relatively constant phase occurring at high substrate concentrations, and finally 3) the "externally" controlled uptake phase, which was substrate-dependent and occurred over a broad range of substrate concentrations but was concentration-dependent and, so, equaled externally controlled uptake rates at substrate concentrations below 3-10 μM. The transient nature of ammonium uptake rate seemed related to rapid changes in small intracellular pools of inorganic nitrogen or amino acids rather than to changes in total N content of the algae. The transient nature of ammonium uptake has important implications for the measurements of uptake rates when either of the two standard methods, the multiple flask and the perturbation technique, are used, and I recommend that a combination of the two methods be used for future uptake experiments.
- Subjects
AMINO acids; AMMONIUM; GREEN algae; ULVACEAE
- Publication
Journal of Phycology, 1994, Vol 30, Issue 6, p980
- ISSN
0022-3646
- Publication type
Article
- DOI
10.1111/j.0022-3646.1994.00980.x