| Abstract Detail
The Functional Significance of Leaf Shape Variation - Towards a Consensus from Gene to Community Rockwell, Fulton [1], Holbrook, Noel [2], Zwieniecki, Maciej A. [3]. Rehydration kinetics of leaves: Implications of hydraulic compartmentalization. The rehydration kinetics of desiccated leaves are well-described as the refilling of at least two distinct pools, each characterized by a different time constant. Here we show that with knowledge of the initial water potential, the time constant of each compartment can be decomposed into a capacitance and resistance term. Applying this method to red oak leaves, we show that this ‘two-compartment’ model predicts significant disequilibrium in water potential within the leaf following rapid changes in leaf water status. Evidence that such disequilibrium does indeed occur is then presented, using an independent rehydration technique. Implications for field measurements of Kleaf, as well as the measurement of transpiring leaf water potentials, are discussed. The response of a two compartment model to oscillations in driving force predicts that the second, slower compartment is protected from short term excursions in potential (under 10 minutes). Finally, we use rehydration kinetics to explore the hydraulic implications of heterobaric versus homobaric leaf structure, with special regard to the constraints imposed by compartmentalization on the transpiration stream.
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1 - Harvard University, Botanical Museum, 26 Oxford St, Cambridge, Massachusetts, 02138, USA
2 - Harvard University, Organismic and Evolutionary Biology
3 - Arnold Arboretum of Harvard University, 125 Arborway, Jamaica Plain, Massachusetts, 02130, USA
Keywords:
hydraulic conductance
leaf hydraulics
functional plant anatomy
Transpiration
rehydration kinetics.
Presentation Type: Symposium or Colloquium Presentation
Session: SY01
Location: Williford B/Hilton
Date: Monday, July 9th, 2007
Time: 2:00 PM
Number: SY01010
Abstract ID:2107 |
