Matric Potentials of Leaves

Abstract

A pressure chamber was used to measure matric potentials of frozen and thawed leaves. Significant matric potentials were demonstrated in sunflower, yew, and rhododendron. Matric potentials were particularly negative in rhododendron and were correlated with the amount of cell wall present and with the volume of water outside the protoplasts at comparable matric potentials. Matric forces in leaves are probably associated mainly with cell walls, at least within the physiological range of water contents. Calculations indicated that the water potential of the solution in the cell wall could be estimated from the sum of matric and osmotic potentials acting on water outside the protoplasts.