Bryological and Lichenological Section/ABLS
d'Artenay, Tamrya D. , Renzaglia, Karen S. .
Evolution of male gametes in liverworts.
The male gamete provides an excellent model for studying ultrastructural changes across lineages in land plants. Where the morphology of the gametophyte and sporophyte of most plants has been examined, the ultrastructure of the male gamete of most land plants remains a mystery. The size and shape of sperm varies with lineage and especially with genome size. It has been cited as a source for overwhelming data in morphological evolution many times, yet has still gone mostly unstudied. This study presents data on male gamete ultrastructure and its relation to evolution across lineages. Each of the major lineages of liverworts is sampled and synapomorphies for that group are identified. Haplomitriopsida, the sister group all other liverworts, has a unique morphology involving a shorter cell with a nucleus that is larger in diameter than any other liverwort outside this clade, and contains two to three plastid where one is the case outside the Haplomitriopsida. The Marchantiopsida are distinguished by a multi-layered structured that tapers to the right, while that of the Jungermanniopsida and Haplomitriopsida taper to the left. Members of the Jungermanniopsida typically have a longer posterior basal body than those of the Haplomitriopsida and Marchantiopsida. Using recent molecular phylogenies of liverworts we can now begin to better understand the overall evolution in morphology of sperm cells and suggest explanations for changes in the ultrastructure among and within lineages.
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1 - Southern Illinois University Carbondale, Plant Biology, 420 Life Science 2, Southern Illinois University , Carbondale, IL, 62901, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 554A/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 10:00 AM