The Hydraulic Design of Mesomorphic Tree Leaves: Hydraulic Resistance, Anatomical Correlates, and the Effects of Damaging Venation
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Authors
Cowan, Peter D.
Issue Date
2001
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
The leaf hydraulic design of sun and shade leaves was investigated for several species of trees at the Harvard Forest in Petersham, MA. Leaf feature measured included leaf hydraulic resistance and stomatal density, and pressure-volume (PV) curves, which provide leaf parameters such as turgor loss point (TLP), leaf capacitance. near TLP (Cd)' and osmotic potentials. Using vacuum infiltration several other characteristics were measured, including specific leaf area (SLA), bulk density, and leaf water content (LWC). A total of 16 aspects of leaf design were measured, ranked, and correlations were sought. Species differences and the effects light regime (sun vs. shade) during development on the leaf characteristics were tested. Significant correlations were. found between leaf parameters. Species differed significantly and the effect of light regime was considerable on leaf resistance, SLA, leaf water content, and turgor loss point. This information will facilitate the. formation of predictive models and deeper
ecological understanding of niche selection of leaf design features. The. study
was expanded to investigate leaf vascular design by cutting the. different leaf
vein orders and measuring effects on transpiration rate. Leaves of Quercus rubra
and Acer saccharum. were. cut to restrict flow to certain veins, experimental leaves
were paired with controls. In Acer most of the.leaves died, while in Quercus they
survived for four weeks, though, there was a marked drop off in transpiration
compared to the controls. This suggest that leaves vary greatly in their ability to
withstand damage, that vein systems are not redundant and that low vein order
may be responsible for most of a leaf's resistance.
Description
iv, 51 p.
Citation
Publisher
Kalamazoo College
License
U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder.