Developmental and Structural Section
Martinez Cabrera, Hugo , Jones, Cynthia S. , Espino, Susana , Schenk, H. Jochen .
Relationships between wood anatomy and wood density in 62 shrubs species from two transcontinental aridity gradients.
Wood density has been correlated with a variety of ecologically important characteristics of trees and shrubs, such as growth strategy, life history traits, and resistance to implosion of vessels. The goal of this study was to explore relationships between wood anatomy and density in shrubs growing along broad aridity gradients in North America and Argentina. Wood density and wood anatomical features were characterized for 62 shrubs species, and anatomical traits were correlated with density with and without consideration of phylogenetically independent contrasts (PICs). Cross-sectional diameters and areas (wall and lumen) occupied by each cell type were measured, and the number and type of cells directly adjacent to vessels were determined. As expected, wood density increased with aridity, largely due to decreases in fiber lumen diameter and fiber size. When using PICs, fiber wall thickness was not correlated with density. Total parenchyma area was not related to wood density, but ray and axial parenchyma areas were directly and inversely correlated with density. Denser woods had comparatively more axial parenchyma and less ray cells directly associated with vessels. Some vessel traits such as mean and hydraulic diameter were correlated with wood density only when PICs were used. Interestingly, total conduction area was not correlated with wood density, indicating that across broad hydraulic gradients, shrubs can have relatively high conduction areas while maintaining high wood densities through adjustments in the fiber lumen/wall ratio. Wood density in shrubs is regulated by adjustments in fiber traits mediating the different compromises of wood function in particular environments and phylogenetically fixed characters.
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1 - University of Connecticut, Ecology and Evolutionary Biology, 75 North Eagleville Rd, U-3043, Storrs, Connecticut, 062693043, USA
2 - University of Connecticut, Dept. of Ecology and Evolutionary Biology, Storrs, CT, 06269, USA
3 - California State University Fullerton, Department of Biological Science, Fullerton, CA, P.O. Box 6850, USA
4 - California State University Fullerton, Department of Biological Science, PO Box 6850, Fullerton, California, 92834-6850, USA
Presentation Type: Poster:Posters for Sections
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM