Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): D.R. Woodruff; B.J. Bond; F.C. Meinzer
    Date: 2004
    Source: Plant, Cell, and Environment. 27: 229-236
    Publication Series: Scientific Journal (JRNL)
    PDF: Download Publication  (754 KB)


    The gravitational component of water potential contributes a standing 0.01 MPa m1 to the xylem tension gradient in plants. In tall trees, this contribution can significantly reduce the water potential near the tree tops. The turgor of cells in buds and leaves is expected to decrease in direct proportion with leaf water potential along a height gradient unless osmotic adjustment occurs. The pressure-volume technique was used to characterize height-dependent variation in leaf tissue water relations and shoot growth characteristics in young and old Douglas-fir trees to determine the extent to which growth limitation with increasing height may be linked to the influence of the gravitational water potential gradient on leaf turgor. Values of leaf water potential, bulk osmotic potential at full and zero turgor, and other key tissue water relations characteristics were estimated on foliage obtained at 13.5 m near the tops of young (approximately 25-year-old) trees and at 34.7, 44.2 and 55.6 m in the crowns of old-growth (approximately 450-year-old) trees during portions of three consecutive growing seasons. The sampling periods coincided with bud swelling, expansion and maturation of new foliage. Vertical gradients of leaf water potential and pressure-volume analyses indicated that turgor decreased with increasing height, particularly during the late spring when vegetative buds began to swell. Vertical trends in branch elongation, leaf dimensions and leaf mass per area were consistent with increasing turgor limitation on shoot growth with increasing height. During the late spring (May), no osmotic adjustment to compensate for the gravitational gradient of leaf water potential was observed. By July, osmotic adjustment had occurred, but it was not sufficient to fully compensate for the vertical gradient of leaf water potential. In tall trees, the gravitational component of leaf water potential is superimposed on phenologically driven changes in leaf water relations characteristics, imposing potential constraints on turgor that may be indistinguishable from those associated with soil water deficits.

    Publication Notes

    • Visit PNW's Publication Request Page to request a hard copy of this publication.
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.


    Woodruff, D.R.; Bond, B.J.; Meinzer, F.C. 2004. Does turgor limit growth in tall trees?. Plant, Cell, and Environment. 27: 229-236


    Pseudotsuga menziesii, Douglas-fir, gravitational component, water potential, height growth, osmotic adjustment, pressure-volume curve, turgor maintenance.

    Related Search

    XML: View XML
Show More
Show Fewer
Jump to Top of Page