Ion compartmentation inPorphyra umbilicalisdetermined by electron-probe X-ray microanalysis

摘要

The ion composition of cell compartments in the intertidal red algaPorphyra umbilicalisadapted for two weeks in 3.5 x artificial seawater was determined by X-ray microanalysis of unfixed, frozen, bulk specimens. A procedure is described for the calculation of ion concentrations in the main cell compartment, cytoplasm, vacuoles and plastid. The results indicate high K+and low Na+concentrations in cytoplasm and plastid. Sodium ions are preferentially localized in vacuoles. Both, vacuoles and plastid contain high Cl-concentrations.