Abstract Detail

Ecology

Ansaldi, Beth [1], Franks, Steven [1], Weber, Jennifer [2].

Abiotic predictors of breeding system variation in Triodanis perfoliata across a large geographic distribution.

Plant breeding systems can vary widely among populations, yet few studies have investigated what drives variation among populations across a geographic range. Investigating the relationship between environmental factors and breeding system variation can provide insight into the evolution of mixed mating systems, including dimorphic cleistogamy. This study represents one of the first large-scale studies of inter-population variation in reproductive allocation to cleistogamy. Dimorphic cleistogamous plants reproduce within both exclusively selfing (cleistogamous, CL) and facultative outcrossing (chasmogamous, CH) flowers. Previous studies have shown that cleistogamous species can preferentially allocate resources toward CH or CL reproduction, potentially as plastic responses to resource or pollination conditions.
In this study, we examined the relationship between abiotic conditions (temperature, precipitation and soil characteristics) and Triodanis perfoliata breeding system variation, defined by total flower production, flower production by flower type and relative production of CH flowers. We examined 14 populations representing approximately 25% of the species range, and spanning 1500km of the U.S. eastern coastline. Average relative proportion of CH flowers varied among populations, ranging from 0.00362–0.576 (CH/Total flowers). We built conditional autoregressive models, which control for spatial autocorrelation, to elucidate environmental correlates of breeding system variation. Silt content, which influences water availability, was a significant positive predictor of CH, CL and total flower counts, but not relative production of CH flowers. Precipitation during the warmest annual quarter was a significant positive predictor of relative CH flowers. We did not detect a significant relationship between flower number or proportion of CH flowers and other factors such as latitude, longitude, or temperature.
To our knowledge, this is the first study to link climatic and soil characteristics to variation in a cleistogamous breeding system across a geographic range. Our results provide some support for the idea that water availability is a limiting resource for CH flowers, which have a large exposed surface area and thus likely lose more water than closed CL flowers. To complement this large-scale perspective, future studies focusing on microclimate variables and biotic factors would be informative. Our complementary work has shown that pollinator environment affects variation in breeding system and our forthcoming work will quantify inbreeding depression in T. perfoliata. Together, these studies elucidate some of the most important ecological and evolutionary predictors of breeding system variation.

1 - Fordham University Department of Biological Sciences, 441 East Fordham Road, Bronx, New York, 10458
2 - Southern IL University, Carbondale, Department of Plant Biology, Carbondale, IL, 62901, USA

Keywords:
breeding system
cleistogamy
intraspecific variation.

Presentation Type: Poster
Session: P, Ecology Section Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM This poster will be presented at 5:30 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PEC027
Abstract ID:673
Candidate for Awards:None