This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Turner, N. C. Articles by Schulze, E.-D. Search for Related Content PubMed PubMed Citation Articles by Turner, N. C. Articles by Schulze, E.-D. Agricola Articles by Turner, N. C. Articles by Schulze, E.-D.

Articles

Comparison of Water Potentials Measured by In Situ Psychrometry and Pressure Chamber in Morphologically Different Species ¹

CSIRO Division of Plant Industry, Private Bag, Wembley, W. A. 6014, Australia, NSW Department of Agriculture, Agricultural Research Station, Narrabri, N. S. W. 2390, Australia, Lehrstuhl für Pflanzenökologie, Universität Bayreuth, 8580 Bayreuth, West Germany

Leaf water potentials measured by in situ psychrometry were compared with leaf water potentials measured by the pressure chamber technique at various values of water potential in Helianthus annuus, Helianthus nuttallii, Vigna unguiculata, Nerium oleander, Pistacia vera, and Corylus avellana. In V. unguiculata, the leaf water potentials measured by the in situ psychrometer oscillated at the same periodicity as, and proportional to, the leaf conductance. In all species, potentials measured by in situ psychrometers operating in the psychrometric mode were linearly correlated with potentials measured with the pressure chamber. However, the in situ psychrometers underestimated the leaf water potential in the two Helianthus species at low water potentials and overestimated the water potential in P. vera, N. oleander, and C. avellana. The underestimation in the two Helianthus species at low water potentials resulted from differences in water potential across the leaf. The overestimation in P. vera, N. oleander, and C. avellana was considered to arise from low epidermal conductances in these species even after abrasion of the cuticle. Pressure-volume studies with Lycopersicon esculentum showed that less water was expressed from distal than proximal leaflets when the whole leaf was slowly pressurized. The implication of this for water relations characteristics obtained by pressure-volume techniques is discussed. We conclude that in situ psychrometers are suitable for following dynamic changes in leaf water potential, but should be used with caution on leaves with low epidermal conductances.

This article has been cited by other articles:

				C. S. Campbell and K. J. McInnes Response of In Situ Leaf Psychrometer to Cuticle Removal by Abrasion Agron. J., September 1, 1999; 91(5): 859 - 862. [Abstract] [Full Text]

				N. M. Holbrook, M. J. Burns, and C. B. Field Negative Xylem Pressures in Plants: A Test of the Balancing Pressure Technique Science, November 17, 1995; 270(5239): 1193 - 1194. [Abstract] [PDF]