Plant water status of apple trees and its measurement in the field. II. Comparison of the dye technique and the vapour equilibration technique for the measurement of leaf water potential

Abstract

The dye technique, developed after Shardakov's method, for the measurement of leaf water potentials may be subject to contamination errors or errors arising from solute uptake by leaf discs. A measure of this total error arising from these sources was made by a comparison of the dye method with Slatyer's vapour equilibration technique. Differences in leaf water potentials measured with the two techniques were small and limits were not in excess of ± 1 atm for the three apple varieties tested. The accuracy, speed and portability of the dye method should make this method quite suitable for field measurements of plant water stress in apple trees.