Abstract Detail



Pteridology

Grusz, Amanda [1], Windham, Michael D. [2], Picard, Kathryn [3], Pryer, Kathleen [4], Schuettpelz, Eric [5], Haufler, Christopher [6].

An environmentally-based model for the origin of obligate apomixis in ferns: insights from the pellaeid clade (Pteridaceae; Cheilanthoideae).

Xeric environments impose major constraints on plant life histories and the fern life cycle is especially vulnerable. To overcome these limitations, many fern lineages in drought-prone areas have evolved an apomictic life cycle. Here, we synthesize studies of apomixis in ferns and present an evidence-based model for the establishment and evolution of this reproductive strategy, focusing on genetic and environmental factors that are associated with its two defining traits—the production of ‘unreduced’ spores (n = 2n) and the initiation of sporophytes from somatic gametophyte tissue (i.e., apogamy). Existing literature is evaluated in light of the hypothesis that abiotic characteristics of desert environments in particular (e.g., extreme diurnal fluctuations in temperature, high light intensity, and water-limitation) drive the evolution of obligate apomixis in ferns. Pellaeid ferns (Cheilanthoideae: Pteridaceae), replete with well-studied apomictic lineages, are examined in detail as an illustrative example. A plastid (rbcL, trnG–trnR, atpA) phylogeny is reconstructed for the clade and reproductive mode and ploidy are mapped across the resulting tree. Leveraging this fresh phylogenetic perspective, we then evaluate our model in the context of existing evidence and novel insights from pellaeid ferns.


1 - University Of Minnesota Duluth, Biology, 1035 Kirby Drive, SSB 207, Duluth, MN, 55812, United States
2 - Duke University, Biology, Durham, NC, 27708, USA
3 - Smithsonian Institution, Botany, Washington, DC, 20013, USA
4 - Duke University, Biology, Duke University, Science Drive, Durham, NC, 27708, United States
5 - Smithsonian Institution, Department Of Botany, MRC 166 PO Box 37012, Washington, DC, 20013, United States
6 - University Of Kansas, Department Of Ecology And Evolutionary Biology, 1200 Sunnyside Avenue, Haworth Hall, Lawrence, KS, 66045, United States

Keywords:
agamospory
apogamy
asexual
diplospory
Döpp-Manton sporogenesis
meiotic obligate apogamy
premeiotic endomitosis.

Presentation Type: Oral Paper
Number: PTER2003
Abstract ID:814
Candidate for Awards:Edgar T. Wherry award


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