| Abstract Detail
Systematics Section/ASPT Gallaher, Timothy [1], Cox, Monica [1], Cotton, Joseph [2], Sanchez-Ken, J. Gabriel [3], Clark, Lynn G. [1]. Chlorenchyma and bundle sheath cell shape in the Poaceae: a 3-D approach to reconstructing the evolution of anatomical enablers of diversification. The Poaceae is a model system for understanding terrestrial plant diversification due to the ubiquitous distribution of the family and its ecological importance. From a C3 origin in tropical forests, several lineages within the family have adapted to open habitats, evolving the “typical” linear grass leaf each time from a plesiomorphic broad, pseudopetiolate leaf. In most, if not all, of these lineages, adaptation to open habitats and later the evolution of C4 photosynthesis appear to have been accompanied or preceded by modifications of internal leaf anatomy. These “anatomical enablers” have been most thoroughly studied with regard to C4 photosynthesis and include differential development of the chloroplasts, decreases in interveinal distance, and changes in the shape and arrangement of bundle sheath cells, chlorenchyma, and intercellular spaces. However, these correlations between functional adaptations and leaf anatomy were observed largely from cross-sections, typically without analysis of the longitudinal and paradermal planes. That approach ignores additional anatomical information present in the leaf and in some cases can result in misinterpretation of fundamental anatomy. The few studies in the literature incorporating all three dimensions focus on only a few groups within the family to draw rough comparisons, and these studies suggest that there are additional anatomical characters of importance when the other dimensions are considered individually or in combination. In this study we reconstruct the evolution of bundle sheath and chlorenchyma cell shapes and their interactions in three dimensions over the entire grass family. Specifically we investigate correlations between gross leaf morphology, three-dimensional leaf anatomy, habitat, and photosynthesis type (including C4 subtypes) within a phylogenetic framework. Preliminary results suggest interesting transitions in the direction of lobing of the chlorenchyma cells and changes in the degree or direction of elongation in both chlorenchyma and bundle sheath cells throughout the grass phylogeny. Our results have implications for a better understanding of the evolution of the Poaceae, and moreover provide insight into the evolution of anatomical modifications leading to adaptations to open habitats and the origins of C4 photosynthesis within the family.
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1 - Iowa State University, Department Of Ecology, Evolution, And Organismal Biology, 251 Bessey Hall, Ames, IA, 50011-1020, USA
2 - Northern Illinois University, Department of Biological Sciences, Montgomery Hall, DeKalb, IL, 60115, USA
3 - Av. Col. del Valle 216 int 2, Col. del Valle, Delegación Benito Juarez, 03100, Mexico
Keywords:
Poaceae
Grass
3D reconstruction
Photosynthesis pathway
Adaptation
diversification
leaf anatomy.
Presentation Type: Oral Paper:Papers for Sections
Session: 13
Location: Pines South/Boise Centre
Date: Monday, July 28th, 2014
Time: 4:00 PM
Number: 13010
Abstract ID:612
Candidate for Awards:None |
