Potassium accumulation and sodium efflux by Porphyra perforata tissues in lithium and magnesium sea water
- PMID: 13820476
- PMCID: PMC2194965
- DOI: 10.1085/jgp.43.1.29
Potassium accumulation and sodium efflux by Porphyra perforata tissues in lithium and magnesium sea water
Abstract
Cells of Porphyra perforata, a red marine alga, accumulate K in the absence of concomitant Na or Li extrusion while immersed in Li- or Mg-sea waters lacking Na. This suggests that the coupling observed between K and Na transport is facultative. No evidence is obtained for net extrusion of Li. Na efflux, with the concentration gradient, is facilitated by K and is proportional to the cellular Na content. Either Na efflux does not involve an ion carrier or the number of Na sites is large. Because K accumulation has been observed in the absence of Na extrusion, but not vice versa, it seems that K uptake is the primary secretory event, with Na extrusion a secondary process dependent upon K accumulation.
