Abstract Detail

Reproductive Processes

Di Stilio, Verónica S. [1], Hartogs, Samantha R. [2], Martinez-Gomez, Jesus  [3], Tank, David [4].

Characterizing wind pollination syndrome, its tempo and mode of evolution in Thalictrum (Ranunculaceae).

Wind pollination syndrome represents a complex phenotype that has evolved repeatedly in angiosperms, but the mechanisms involved in its origin are largely unexplored. Thalictrum (Ranunculaceae) is an ideal system to study the tempo and mode of the evolution of wind pollination, as this shift has occurred repeatedly from insect pollination. Here, we investigate floral traits and their phylogenetic pattern of correlated evolution in a subset of species within the genus Thalictrum. Our goal is to 1) identify suites of floral characters contributing to the wind pollination syndrome, and 2) characterize phylogenetic patterns of correlated trait evolution, their tempo and mode. The end goal is to determine whether wind pollination evolved through same or different mechanisms each time, both at the morphological and genetic level. Flower scans from live plants and herbarium specimens were used to obtain continuous and discreet morphological data with both pollination syndromes, such as perianth, style, stamen, and ovary dimensions. Multivariate analysis of floral traits using Principal Component Analysis and K-means resulted in species falling into distinct clusters that can be assigned to pollination syndrome and/or sexual system, even after correcting for phylogenetic relatedness. To identify patterns of correlated trait evolution we infer ancestral states of carpel and stamen dimensions under continues models of morphological evolution. Additionally, we found signal of perianth sexual dimorphism within dioecious species. To quantify the rate of trait evolution, phylogenetic comparative analyses of trait data were assessed. A preliminary analysis for anther surface area and stigma length in 20 species suggested that there is more uncertainty (larger variance) in evolutionary rate estimates associated with wind than insect pollination. We hypothesize that this is the signature of the independent origins of wind pollination in the clade, where different mechanisms may be responsible for convergent phenotypes.

1 - University of Washington, Biology, Box 351800, Seattle, WA, 98195-1800, USA
2 - University of Washington, Biology
3 - University of California Berkeley, Integrative Biology, Berkeley, CA, United States
4 - University of Idaho, Department of Biological Sciences, 875 Perimeter Drive MS 3051, Moscow, ID, 83843, USA

Keywords:
pollination syndrome
Floral traits
wind pollination
PCA
convergence
meadow rues.

Presentation Type: Oral Paper
Session: 16, Reproductive Processes I
Location: 111/Mayo Civic Center
Date: Tuesday, July 24th, 2018
Time: 9:30 AM
Number: 16007
Abstract ID:916
Candidate for Awards:None