Abstract Detail

Reproductive Processes

Joly, Simon [1], Schoen, Daniel [2].

Evolution of cleistogamy is strongly associated with zygomorphy in flowering plants.

The shift from outcrossing to self-pollination is perhaps the most common evolutionary transition in the flowering plants. One of the most distinctive and poorly understood modes of selfing is cleistogamy, in which selfing occurs autonomously in specialized “cleistogamous” (CL) flowers that are closed and reduced in size compared with the typically cross-pollinated “chasmogamous” (CH) flowers borne on the same plant. Charles Darwin noted in 1877 that cleistogamous species tend to be more common in bilaterally symmetric (zygomorphic) flowers than in those with radially-symmetric (actinomorphic) flowers. Because cleistogamy ensures pollination, he suggested that this is because pollination is less certain in zygomorphic species that rely on a more specialized guild of pollinators. We gathered a large dataset of 2,523 species on floral symmetry and cleistogamy and reconstructed a phylogeny for these species. We then tested Darwin’s hypothesis using a phylogenetic logistic regression and models of evolution for correlated characters. We show that cleistogamy is disproportionately associated with zygomorphic flowers.

1 - Montreal Botanical Garden, 4101 Sherbrooke East, Montreal, QC, H1X 2B2, Canada
2 - McGill University, Biology, 1205 Docteur Penfield, Montreal, Qc, H3A 1B1, Canada

Keywords:
plant reproduction
mating system
evolution
flower symmetry
floral evolution.

Presentation Type: Oral Paper
Session: REP1, Reproductive Processes 1
Location: Virtual/Virtual
Date: Wednesday, July 29th, 2020
Time: 11:00 AM
Number: REP1005
Abstract ID:718
Candidate for Awards:None