Plant Physiology Preview
Published on April 2, 2004; 10.1104/pp.103.031203
Received July 31, 2003
Returned for revision December 21, 2003
Accepted January 5, 2004
Hydraulic Analysis of Water Flow through Leaves of Sugar Maple and Red Oak
Lawren Sack *, Christopher M. Streeter , and N. Michele Holbrook
Biological Laboratories, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138; Harvard Forest, Petersham, Massachusetts 01366; The Arnold Arboretum of Harvard University, Jamaica Plain, Massachusetts 02130
Harvard Forest, Petersham, Massachusetts 01366
Biological Laboratories, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138
* Corresponding author; email: lsack{at}hawaii.edu.
Leaves constitute a substantial fraction of the total resistance to water flow through plants. A key question is how hydraulic resistance within the leaf is distributed among petiole, major veins, minor veins, and the pathways downstream of the veins. We partitioned the leaf hydraulic resistance (R
leaf) for sugar maple (Acer saccharum) and red oak (Quercus rubra) by measuring the resistance to water flow through leaves before and after cutting specific vein orders. Simulations using an electronic circuit analog with resistors arranged in a hierarchical reticulate network justified the partitioning of total R
leaf into component additive resistances. On average 64% and 74% of the R
leaf was situated within the leaf xylem for sugar maple and red oak, respectively. Substantial resistance--32% and 49%-- was in the minor venation, 18% and 21% in the major venation, and 14% and 4% in the petiole. The large number of parallel paths (i.e. a large transfer surface) for water leaving the minor veins through the bundle sheath and out of the leaf resulted in the pathways outside the venation comprising only 36% and 26% of R
leaf. Changing leaf temperature during measurement of R
leaf for intact leaves resulted in a temperature response beyond that expected from changes in viscosity. The extra response was not found for leaves with veins cut, indicating that water crosses cell membranes after it leaves the xylem. The large proportion of resistance in the venation can explain why stomata respond to leaf xylem damage and cavitation. The hydraulic importance of the leaf vein system suggests that the diversity of vein system architectures observed in angiosperms may reflect variation in whole-leaf hydraulic capacity.
This article has been cited by other articles:
|
|
|
|
 
M. C. Voicu, J. E. K. Cooke, and J. J. Zwiazek
Aquaporin gene expression and apoplastic water flow in bur oak (Quercus macrocarpa) leaves in relation to the light response of leaf hydraulic conductance
J. Exp. Bot.,
October 1, 2009;
60(14):
4063 - 4075.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
D.M. Johnson, D.R. Woodruff, K.A. McCulloh, and F.C. Meinzer
Leaf hydraulic conductance, measured in situ, declines and recovers daily: leaf hydraulics, water potential and stomatal conductance in four temperate and three tropical tree species
Tree Physiol,
July 1, 2009;
29(7):
879 - 887.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
E. Gortan, A. Nardini, A. Gasco, and S. Salleo
The hydraulic conductance of Fraxinus ornus leaves is constrained by soil water availability and coordinated with gas exchange rates
Tree Physiol,
April 1, 2009;
29(4):
529 - 539.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
L. Sack, E. M. Dietrich, C. M. Streeter, D. Sanchez-Gomez, and N. M. Holbrook
Leaf palmate venation and vascular redundancy confer tolerance of hydraulic disruption
PNAS,
February 5, 2008;
105(5):
1567 - 1572.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. Sakurai, A. Ahamed, M. Murai, M. Maeshima, and M. Uemura
Tissue and Cell-Specific Localization of Rice Aquaporins and Their Water Transport Activities
Plant Cell Physiol.,
January 1, 2008;
49(1):
30 - 39.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
H. Cochard, J.-S. Venisse, T. S. Barigah, N. Brunel, S. Herbette, A. Guilliot, M. T. Tyree, and S. Sakr
Putative Role of Aquaporins in Variable Hydraulic Conductance of Leaves in Response to Light
Plant Physiology,
January 1, 2007;
143(1):
122 - 133.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. Y. Tang, R. E. Zielinski, A. R. Zangerl, A. R. Crofts, M. R. Berenbaum, and E. H. DeLucia
The differential effects of herbivory by first and fourth instars of Trichoplusia ni (Lepidoptera: Noctuidae) on photosynthesis in Arabidopsis thaliana
J. Exp. Bot.,
February 1, 2006;
57(3):
527 - 536.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. Nardini and S. Salleo
Water stress-induced modifications of leaf hydraulic architecture in sunflower: co-ordination with gas exchange
J. Exp. Bot.,
December 1, 2005;
56(422):
3093 - 3101.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. T. Tyree, A. Nardini, S. Salleo, L. Sack, and B. El Omari
The dependence of leaf hydraulic conductance on irradiance during HPFM measurements: any role for stomatal response?
J. Exp. Bot.,
February 1, 2005;
56(412):
737 - 744.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
