Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Landis, Jacob [1], O'Toole, Rebecca D. [3], David, Oppenheimer [2], Soltis, Douglas E. [3], SOLTIS, PAMELA S. [3].

Determining the cellular component of flower size differences in Saltugilia (Polemoniaceae).

Corolla length has been shown to have strong implications for pollinator success. Even when specific plant-pollinator relationships are well understood, the phenotypic and genetic underpinnings of corolla elongation are not well known. In this study, we investigate the cellular phenotypic differences in corolla length in Saltugilia (Polemoniaceae). Saltugilia, with six taxa, exhibits striking variation in corolla length, and transitions have been identified through character mapping of corolla length and width on a densely sampled phylogeny of Polemoniaceae. Flowers of each species were collected from multiple individuals during four stages of flower development to determine whether cell number or cell size was more important in determining flower length, as well as to determine how much morphological variation exists between individuals from a given population of a species. Flowers were fixed, dehydrated, and stained before being visualized with a confocal microscope. Values of compactness were used to ensure comparison of cell size was conducted on homologous regions of the flower. From these analyses, three distinct cell types were observed in all development stages, with a fourth cell type only found in fully mature flowers. Average values of cell size for all cell types were mapped onto a phylogeny to determine the direction of observed transitions. Initial analyses indicate that directionality of change in flower size is mediated by alternative processes:  that is, floral elongation is caused by increases in cell size, and transitions to smaller flowers are determined by decrease in cell number.  As a comparative study for future genetic investigations, we conducted similar analyses in several species of Petunia (Solanaceae). Flower development at the cellular level appears to differ between Saltugilia and Petunia, with different cell types forming at different stages. This suggests that flower size may be controlled by many genes and that the genetic control of flower size may differ phylogenetically.

1 - University Of Florida, Dept Of Biology, Florida Museum Of Natural History - Dickinson Hall, Museum Road And Newell Drive, Gainesville, FL, 32611, USA
2 - University of Florida, Department of Biology, 220 Bartram Hall, PO Box 118525, Gainesville, FL, 32611, USA
3 - University of Florida, Florida Museum of Natural History, PO Box 117800, Gainesville, FL, 32611, USA

Keywords:
flower size
Polemoniaceae
Saltugilia
pollinator
cell size.

Presentation Type: Oral Paper:Papers for Topics
Session: 46
Location: Payette/Boise Centre
Date: Wednesday, July 30th, 2014
Time: 5:00 PM
Number: 46006
Abstract ID:499
Candidate for Awards:Katherine Esau Award