An Apparatus For Measuring Water Potentials in the Xylem of Intact Plants

Abstract

A new method and apparatus for estimating water potentials in the xylem of intact plants are described. The apparatus is based on the thermocouple psychro-meter method of measuring water potentials, but measurements are made on leaves which remain attached to plants. Illustrative experiments are described, in which continuous records of the estimated water potential in the xylem of cotton and pepper plants are given for periods of up to 10 hr.