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Abstract Detail

Systematics Section

Givnish, Thomas J. [1], Ames, Mercedes S. [2], McKain, Michael R.  [3], Steele, P. Roxanne [4], dePamphilis, Claude W. [5], Graham, Sean W. [6], Pires, J. Chris [7], Stevenson, Dennis Wm. [8], Zomlefer, W. B. [9], Briggs, Barbara [10], Duvall, Melvin R. [11], Moore, Michael [12], Soltis, Douglas E. [13], Soltis, Pamela S. [14], Thiele, Kevin [15], Leebens-Mack, James H. [16].

Plastome sequence phylogeny of commelinid monocots implies five origins of wind pollination in Poales.

Poales comprises 7% of all angiosperms and 33% of monocots, and includes taxa of enormous economic and ecological significance. Previous studies have left uncertain many relationships within Poales and among allied commelinid orders. Here we present the results of a study on phylogeny and evolution in Poales, using sequence data for 81 plastid genes (> 101 aligned kb) from 83 species of angiosperms. We recovered highly concordant relationships using ML and MP, generally with very strong support (98.2% mean ML bootstrap support across monocot nodes). For the first time, ML resolves ties among Poales and other commelinid orders with moderate to strong support. Analyses provide strong support for Bromeliaceae being sister to all other Poales; Typhaceae, Rapateaceae, and cyperids (sedges, rushes, and their allies) emerge next along the phylogenetic spine. Graminids (grasses and their allies) and restiids (Restionaceae and its allies) are well supported as sister taxa. MP identifies a xyrid clade sister to cyperids, but ML (with much stronger support) places them as a grade with respect to restiids + graminids. The conflict in resolution between these analyses likely reflects long-branch attraction and highly elevated substitution rates in some Poales. All other familial relationships within the order are strongly supported by both analyses. Character-state mapping implies that ancestral Poales lived in sunny, fire-prone, seasonally damp/wet, and possibly nutrient-poor sites, and were animal pollinated. Five subsequent shifts to wind pollination in Typhaceae, cyperids, restiids, Ecdeiocoleaceae, and the bistigmatic clade of grasses are significantly correlated with shifts to open habitats and small, inconspicuous, unisexual, nectar-free flowers. Prime drivers of the repeated evolution of wind pollination iappear to include open habitats combined with high dominance of conspecifics, with the latter resulting from large-scale disturbances, tall plant stature, vigorous vegetative spread, and/or positive ecological feedbacks. Reproductive assurance in the absence of reliable animal visitation probably favored wind pollination in annuals and short-statured perennials of Centrolepidaceae in ephemerally wet depressions and windswept alpine sites.

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1 - University of Wisconsin-Madison, Department of Botany, 430 Lincoln Drive, Birge Hall, Madison, WI, 53706, USA
2 - University of Wisconsin-Madison, Botany, 206 Natchez Trace, Madison, WI, 53706, United States
3 - University of Georgia, Department of Plant Biology, 4504 Miller Plant Sciences, Athens, GA, 30602, USA
4 - University of Missouri, Department of Biological Sciences, Columbia, MO, 65211, USA
5 - The Pennsylvania State University, Biology, Institute of Molecular Evolutionary Genetics, and The Huck Institutes of the Life Sciences, University Park, PA, 16802, USA
6 - University of British Columbia, UBC Botanical Garden and Certre for Plant Research, 6804 SW Marine Drive, Vancouver, BC, V4T 1Z4, Canada
7 - University of Missouri, Biological Sciences, 1201 Rollins Road, 311 Life Sciences Center, Columbia, Missouri, 65211, USA
8 - New York Botanical Garden, Institute of Systematic Botany, 200Th Street & Southern Boulevard, Bronx, New York, 10458-5126, USA
9 - University of Georgia, Department of Plant Biology, 2052 Miller Plant Sciences Building, Athens, Georgia, 30602-7271, USA
10 - Royal Botanic Gardens, Mrs Macquaries Road, Sydney, New South Wales, 2000, Australia
11 - Northern Illinois University, Department of Biological Sciences, Montgomery Hall, DeKalb, Illinois, 60115-2861, USA
12 - Oberlin College, Biology Department, 119 Woodland Street, Science Center K111, Oberlin, Ohio, 44074-1097, USA
13 - University of Florida, Department of Botany, 220 Bartram Hall, P.O. Box 118526, Gainesville, Florida, 32611-8526, USA
14 - Florida Museum of Natural History, Dickinson Hall, P.O. Box 117800, Gainesville, Florida, 32611, USA
15 - Western Australian Herbarium, Perth, WA, 6983
16 - University of Georgia, Plant Biology, Athens, GA, 30602

correlated evolution
long branch attraction

Presentation Type: Oral Paper:Papers for Sections
Session: 26
Location: 556B/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 8:00 AM
Number: 26001
Abstract ID:222

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