Abstract Detail

Reproductive Processes

Simpson, Kyle [1], Spalink, Daniel [2].

Floral morphometrics reflect the repeated evolution of selfing in the genus Leavenworthia (Brassicaceae).

Plants differ in their reproductive traits across both closely related taxonomic groups and geographic space. Describing how variation in these reproductive traits is structured at the population level and across a species’ range is important for understanding the evolution of reproductive strategies and elucidating the biogeographic drivers that contribute to variation in reproductive traits.
Here, we use Leavenworthia, a genus of rare plants in the eastern United States that has independently evolved the ability to self at least three times, to investigate the evolution of floral traits in response to geographic isolation and repeated shifts in breeding system. We combine traditional distance-based morphometrics of key floral structures and landmark geometric morphometric analysis of flower shape for over 800 individual flowers, representing the full geographic range of nearly all Leavenworthia species. We analyze these morphometrics using ordination and classification methods to determine how species are arranged in floral morphospace and how variation in floral morphometrics is distributed among populations and across species’ ranges. We test if variation in morphometrics is distributed uniformly across the range of the species or if variation is structured at the population level.
We find that species are generally clustered in morphospace but that species morphoclusters do not necessarily segregate from each other. Instead, segregation in morphospace appears to be based on breeding system. Self-compatible species and self-incompatible species segregate into nearly exclusive regions of morphospace. Additionally, we find that variation in floral morphometrics is generally distributed across the entire range of the species. There does not appear to be strong population differentiation in floral morphometrics, which is surprising considering strong genetic differentiation observed among populations of certain Leavenworthia species.
These results suggest that repeated shifts in breeding system in Leavenworthia have coincided with the convergent evolution of floral traits. They also suggest that despite geographic isolation, Leavenworthia species show limited population structuring of floral morphometrics. These findings have important implications for how we understand breeding system evolution in plants and how variation in floral morphometrics is influenced by geographic isolation and population connectivity.

1 - Texas A&M University, Ecology and Evolutionary Biology Program, 2138 TAMU, College Station, TX, 77843, USA
2 - Texas A&M University, Ecosystem Science And Management, 2138 TAMU, College Station, TX, 77802, United States

breeding system
reproductive biology.

Presentation Type: Oral Paper
Number: RP1003
Abstract ID:846
Candidate for Awards:None

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