HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted 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 ISI Web of Science (8) Citing Articles via Google Scholar Google Scholar Articles by Linton, M. J. Articles by Nobel, P. S. Search for Related Content PubMed PubMed Citation Articles by Linton, M. J. Articles by Nobel, P. S. Agricola Articles by Linton, M. J. Articles by Nobel, P. S.

Loss of water transport capacity due to xylem cavitation in roots of two CAM succulents¹

Department of Organismic Biology, Ecology, and Evolution, University of California,Los Angeles, California 90095-1606

Loss of axial hydraulic conductance as a result of xylem cavitation was examined for roots of the Crassulacean acid metabolism (CAM) succulents Agave deserti and Opuntia ficus-indica. Vulnerability to cavitation was not correlated with either root size or vessel diameter. Agave deserti had a mean cavitation pressure of -0.93 ± 0.08 MPa by both an air-injection and a centrifugal method compared to -0.70 ± 0.02 MPa by the centrifugal method for O. ficus-indica, reflecting the greater tolerance of the former species to low water potentials in its native habitat. Substantial xylem cavitation would occur at a soil water potential of -0.25 MPa, resulting in a predicted 22% loss of conductance for A. deserti and 32% for O. ficus-indica. For an extended drought of 3 mo, further cavitation could cause a 69% loss of conductance for A. deserti and 62% for O. ficus-indica. A model of axial hydraulic flow based upon the cavitation response of these species predicted that water uptake rates are far below the maximum possible, owing to the high root water potentials of these desert succulents. Despite various shoot adaptations to aridity, roots of A. deserti and O. ficus-indica are highly vulnerable to cavitation, which partially limits water uptake in a wet soil but helps reduce water loss to a drying soil.

Key Words: Agave deserti; • embolism • hydraulic conductance • Opuntia ficus-indica; • vessel anatomy • water relations • xylem physiology

This article has been cited by other articles:

				P. H. Maseda and R. J. Fernandez Stay wet or else: three ways in which plants can adjust hydraulically to their environment J. Exp. Bot., December 1, 2006; 57(15): 3963 - 3977. [Abstract] [Full Text] [PDF]

				P. Trifilo, A. Gasco, F. Raimondo, A. Nardini, and S. Salleo Kinetics of recovery of leaf hydraulic conductance and vein functionality from cavitation-induced embolism in sunflower J. Exp. Bot., October 1, 2003; 54(391): 2323 - 2330. [Abstract] [Full Text] [PDF]

				P. Martre, G. B. North, and P. S. Nobel Hydraulic Conductance and Mercury-Sensitive Water Transport for Roots of Opuntia acanthocarpa in Relation to Soil Drying and Rewetting Plant Physiology, May 1, 2001; 126(1): 352 - 362. [Abstract] [Full Text]