Abstract Detail

Evolution, Development, and BSA Genetics of Floral Display - Form, Size, and Arrangement

Kulbaba, Mason W [1], Tomaszewski, Caitlin E [1], Clocher, Ilona C [1], Harder, Lawrence D [2].

Heritability and Fitness Consequences of Architectural Effects Within Inflorescences.

Production of multiple flowers allows the reproductive phenotypes of individual plants to include systematic among-flower variation, the details of which could be adaptive in particular environments. Systematic trait variation within inflorescences could arise from resource competition among a plant’s flowers, or be a developmentally determined feature of flower position, regardless of resource dynamics. The latter, architectural effect is obvious in individual plants that produce distinct floral morphs (e.g., various types of monoecy, peripheral sterile flowers), but manifests more often as continuous floral variation within inflorescences. For architectural effects to be adaptive, differences in the relations of floral traits to flower position among individuals must both cause consistent variation in reproductive performance and be heritable. We assess both aspects of systematic positional variation within inflorescences for natural populations of perfect-flowered Delphinium glaucum (Ranunculaceae) and andromonoecious Anticlea occidentalis (Melanthiaceae). In both species, features of flower size and ovule production decline from bottom to top flowers. In contrast, in D. glaucum anther number is constant among flowers and in A. occidentalis pollen production increases distally for distal staminate flowers, but decreases with position for basal perfect flowers. Consequently, upper flowers in both species emphasize relative male function compared to lower flowers. Experimental emasculation of perfect or staminate flowers for A. occidentalis demonstrated that plants would experience much lower outcrossing if they produced only perfect flowers, whereas complete monoecy would not significantly enhance outcrossing. SNP-based estimates for D. glaucum reveal that both the mean and variance of floral traits exhibit significant heritability, with variance being more heritable for some traits. Related analysis will consider the heritability of within-inflorescence gradients in floral traits. These results illustrate that architectural effects within inflorescences affect reproductive performance and are partially genetically determined, rather than simply representing phenotypic plasticity or developmental instability. Such effects demonstrate that the reproductive phenotypes of angiosperms are functional mosaics shaped by adaptation.

1 - University of Calgary, Biological Sciences, 2500 University Drive NW, Calgary, Alberta, T2N 1N4, Canada
2 - University Of Calgary, Department Of Biological Sciences, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada

Keywords:
architectural effects
heritability
fitness
reproduction.

Presentation Type: Symposium Presentation
Session: SY05, Evolution, Development, and Genetics of Floral Display - Form, Size, and Arrangement
Location: Chatham Ballroom - B/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 10:45 AM
Number: SY05007
Abstract ID:566
Candidate for Awards:None