Abstract Detail

Pteridological Section/AFS

Sessa, Emily Butler [1], Testo, Weston [2], Momin, Rehman [3], Watkins, James [4].

Mating systems in ferns: frequencies, functional significance, and phylogenetic signal.

The fern life cycle involves alternation between two independent, free-living phases: the diploid sporophyte and haploid gametophyte. Fern gametophytes, which develop from a meiotically-produced, single-celled spore, go on to produce eggs and sperm in archegonia and antheridia, respectively. Many species are capable of producing bisexual gametophytes that may undergo an extreme form of selfing, called intragametophytic selfing, which leads to homozygosity at all loci. The unique ability of ferns to experience this extreme form of selfing has fascinated pteridologists for decades and has important implications for fern ecology and evolution. In particular, capacity for intragametophytic selfing may be a critical facilitator of species establishment following single-spore long-distance dispersal or allopolyploidization, when intergametophytic mating (which involves two sibling gametophytes) or outcrossing may be impossible or highly unlikely. Evidence from several lines of inquiry—most prominently studies of isozyme variation—suggests that intragametophytic selfing may not be as common as previously thought. However, no comprehensive survey of fern mating systems has yet attempted to assess what proportion of species undergo this process, how frequently they do so, and whether there are ecological correlates or phylogenetic signal to this reproductive approach.. We have undertaken such a survey, and report our preliminary results based on a phylogenetically dispersed sampling of 40+ species in 17 families. We consider the frequencies of intragametophytic and intergametophytic selfing in the contexts of phylogeny, varying ploidy levels, epiphytic vs. terrestrial taxa, and temperate vs. tropical species.

1 - University of Florida, Department of Biology, Box 118525, Gainesville, FL, 32611, USA
2 - University of Vermont, Department of Plant Biology, 63 Carrigan Drive, 101 Jeffords Hall, Burlington, VT, 05405, USA
3 - Colgate University , Biology, 13 Oak Drive, Hamilton, NY, 13346, USA
4 - Colgate University, Department Of Botany, 129 Ho Science Center, 13 Oak Drive, Hamilton, NY, 13346-1338, USA

Keywords:
fern
pteridophyte
gametophyte
mating system
selfing
outcrossing
polyploidy.

Presentation Type: Oral Paper:Papers for Sections
Session: 7
Location: Pines North/Boise Centre
Date: Monday, July 28th, 2014
Time: 11:00 AM
Number: 7010
Abstract ID:213
Candidate for Awards:Edgar T. Wherry award