McCarthy, Elizabeth W. , Knapp, Sandra , Chase, Mark W. , Baldwin, Ian T. , Leitch , Andrew R. , Le Comber, Steven C. .
The Evolution of Floral Morphology in Nicotiana Polyploids of Different Ages.
The evolution of floral morphology in Nicotiana (Solanaceae) allotetraploids, ranging in age from a few generations (synthetic allotetraploids) to ~4.5 million years old, was examined using geometric morphometrics of floral limb shape, corolla tube length and width metrics, and spectral reflectance measurements of floral color. Floral limb shape in Nicotiana is well described by two characters: the outer shape of the limb, which ranges from round to star-shaped, and the relative size of the corolla tube opening to the floral outline, which ranges from small to large. In floral limb shape, younger allotetraploids tend to be intermediate in shape between those of their diploid progenitors, while older allotetraploids have more divergent forms; however, divergence in floral limb shape can occur rapidly following allopolyploidization. In corolla tube length and width, the majority of allotetraploids have wider and shorter corolla tubes, suggesting more generalist pollination after allopolyploidization. In floral color, allotetraploids can either be intermediate between their progenitors, like one or other progenitor, or divergent. The floral color of N. tabacum is divergent and seems to have resulted from the inheritance of floral plastids which lack chlorophyll from its maternal progenitor and the inheritance of anthocyanin pigmentation from its paternal progenitor. Evidence for convergent evolution of floral form in green/yellow-flowered Nicotiana seems to be linked to hummingbird pollination. Overall, the combined study of floral shape, size, and color in Nicotiana sheds light on the evolution of allopolyploids in the context of pollination.
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1 - Queen Mary, University of London, School of Biological and Chemical Sciences, Mile End Road, London, E1 4NS, UK
2 - Natural History Museum, Department of Botany, Cromwell Road, London, SW7 5BD, UK
3 - Royal Botanic Gardens, Kew, Jodrell Laboratory, Kew, Richmond, Surrey, TW9 3AB, UK
4 - Max Planck Institute for Chemical Ecology, Department of Molecular Ecology, Beutenberg Campus, Hans-Knoll-Str. 8, Jena, 07745, Germany
Presentation Type: Oral Paper:Papers for Topics
Location: Forsyth Room/Chase Park Plaza
Date: Tuesday, July 12th, 2011
Time: 8:45 AM