Evolutionary Developmental Biology (Evo-Devo)
Price, Charles , Green, Walton , Wing, Scott L. , Weitz, Joshua .
The allometry of leaf vascular networks.
Detailed measurements of the geometry of leaf vessel networks are important for understanding the role of leaves in whole plant hydrodynamics and carbon balance. Moreover, knowledge of the geometry and topology of leaf networks will allow the development and testing of theoretical models aimed and understanding the ontogenetic and life history constraints governing their evolution. Unfortunately due to their small size and large number of bifurcations, few exhaustive descriptions of the geometry of entire leaf networks exist. To advance our understanding of these and other questions, we have developed a series of image segmentation and network extraction algorithms that identify the geometry of veins, and the areoles they surround, in leaves. We have bundled these algorithms in a graphical user interface (to be made publically available). These algorithms were used to analyze hundreds of leaf networks from multiple sources including both ontogenetic and interspecific patterns. Across species, total network length and volume behave allometrically when regressed against whole leaf dry mass, wet mass or surface area. In contrast, 2D surface area is isometric. In addition, several network properties appear statistically invariant with increases in leaf size, including mean vein length, and network volume fraction. Intraspecifically, network length, area and volume exhibit negative allometry, positive allometry, and isometry, depending on species identity and leaf shape. The intraspecific allometric slopes are also correlated with other well known measures of leaf investment such as specific leaf area and tissue density. Our combined results provide a more detailed picture of the scaling of leaf form and investment than has been heretofore possible. In addition, the graphical user interface we have developed will allow for investigators to employ these methods within their own data, significantly expanding our knowledge of the life history variability of these important photosynthetic organs.
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1 - Georgia Institute of Technology, School of Biology, Atlanta, GA, 30332, USA
2 - National Museum of Natural History, Smithsonian Institution, Department of Paleobiology, Mrc 121, Washington D.C., 20560, USA
3 - National Museum of Natural History, Smithsonian Institution, Department of Paleobiology, Mrc 121, Washington, DC, 20560, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood A/Snowbird Center
Date: Wednesday, July 29th, 2009
Time: 10:30 AM