MICROSCOPIC CONTRIBUTIONS TO THE PRESSURE-VOLUME-DIAGRAM OF THE CELL-WATER RELATIONS AS DEMONSTRATED WITH SINGLE CELLS AND CELL FILAMENTS

Microscopic contributions to the pressure-volume-diagram of the cell-water relations as demonstrated with single cells and cell filaments. The diagram described by Richter (1978), which is based on the relationship between osmotic potential and cell water volume, is used for the evaluation of microscopic measurements on algae in osmotically active solutions. Pressure-volume curves for Eremosphaera viridis and Spirogyra spp. are very similar to those obtained from organs of higher plants in experiments with a pressure chamber or a thermocouple device. Tissue counterpressure and cell wall water have no influence on data from experiments on single cells with osmotic methods, which therefore give probably less biased values than tissues or organs. Differences in the elasticity of the cell wall, the resistance of the chromatophore against volume changes of the protoplast, and the relative volumes of protoplasm and vacuole show up very distinctly. ε-values for the elasticity of the cell wall were calculated for the cells analysed. The usefulness of the Richter diagram could fully be confirmed for single cells. © 1979 Springer-Verlag.