Na+, C1- and K+ Concentrations in Chlorella emersonii exposed to 100 and 335 mM NaCl

Abstract

After 4-7 days growth of C. emevsonii in 100 and 335 m~ NaCl, Na+ and CI- concentrations in the osmotic volume of the cells were usually only 20-40 m. Internal K+ concentrations did not change appreciably during growth in NaCl or in isosmotic concentrations of neutral osmotica. Thus, there were no large contributions of Na+, Cl- or K+ to osmoregulation of this slightly vacuolated alga. The above usually applied even during periods when there was little or no formation of proline, the main osmotic solute in C, emevsonii, i.e. in the dark and immediately following transfer of cells to 100 mM NaCl in the light. However, transfer of cells from 1 to 335 m~ NaCl transiently increased Na+ contents with concurrent, equivalent, decreases in K+ (cell volume basis).