Green, Walton , Hickey, L. J. , Little, Stefan A. , Price, Charles , Weitz, Joshua , Wing, Scott L. .
Disentangling ecological and phylogenetic signals in leaf venation patterns.
The veins in vascular plant leaves distribute water and nutrients, transport photosynthate, and provide structural support and reinforcement of photosynthetic tissue, under the constraints of existing developmental pathways, and phylogenetic history. Leaves are one of the most commonly fossilized plant organs, and they often preserve vein networks in detail. Venation patterns are therefore potentially useful for taxonomic identification of fossils, for examination of evolutionary change through time, and for reconstruction of ancient environments.
In the past, however, it has proved difficult to measure the venation even of modern leaves completely, or to characterize the relationships between specific aspects of a vein network and their associated functions or phylogenetic significance. Most earlier work, therefore, has either been qualitative or focussed on single characters.
Using photographs of modern cleared leaves and image analysis software, we have succeeded in measuring a number of attributes of the vein network of more than 100 leaves, representing most major angiosperm groups and a few ferns. The measurements are repeatable and correspond to intuitive and descriptive notions of vein organization, like areole size and shape. We have observed significant relationships between venation attributes and ecological variables like growth form. Attributes of venation are also not randomly distributed phylogenetically. This supports the contention that leaf venation patterns encode ecological and historical signals, and gives promise that multivariate quantitative data will help disentangle them.
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1 - National Museum of Natural History, Smithsonian Institution, Department of Paleobiology, Mrc 121, Washington D.C., 20560, USA
2 - Yale University, Department of Geology & Geophysics, Yale Station, P.O. Box 208109, New Haven, Connecticut, 06520-8109, USA
3 - Pennsylvania State University, Department of Geosciences, University Park, PA, 16802, USA
4 - Georgia Institute of Technology, School of Biology, Atlanta, GA, 30332, USA
5 - National Museum of Natural History, Smithsonian Institution, Department of Paleobiology, Mrc 121, Washington, DC, 20560, USA
Presentation Type: Poster:Posters for BSA Sections
Location: Event Tent/Cliff Lodge
Date: Tuesday, July 28th, 2009
Time: 5:30 PM