A simple pressure-probe method for the determination of volume in higher-plant cells

A method is described for estimating volume in higher-plant cells from their behaviour under pressure probe. The method utilises differences between initial and final equilibrium turgor pressures associated with a pressure-relaxation experiment. The validity of the approach is tested using model parameters, and by comparing cell volumes obtained using the method with those estimated from direct visual inspection of the same cells. The range of practical application is limited by certain cell parameters, especially osmotic pressure. Nevertheless the method will be useful for many types of higher-plant cell, particularly those of irregular shape or those that are deeply embedded within plant tissues.