Pressure and Solute Potentials in Stomatal Cells ofTradescantia virginiana

Abstract

The postulated mechanical advantage of subsidiary cells over guard cells has been estimated using leaves of Tradescantia virginiana. The turgor pressures of subsidiary cells were adjusted to be zero or maximal by plasmolytic treatments, and the resulting stomatal apertures were measured. The ‘mechanical advantage’ was calculated from two mathematical models which define it as an ‘antagonism ratio’. The discussion deals with methods of preparing the tissue, the validity of the plasmolytic treatments, and the function of the antagonism ratio in relation to the Spannungsphase