Taylor, Wilson , Gontarek, Bryan .
The search for extant analogues for early land plant algal progenitors.
The aquatic algal ancestors that gave rise to the earliest terrestrial plants are not normally expected to have left much in the way of fossil remains, lacking as they likely were in recalcitrant (hence preservable) tissues. The one possible exception to this is the dispersal bodies (spores). Palynologists have long recognized the widespread and continuous record of microscopic,acid-insoluble, acetolysis-resistant bodies from various depositional environments, but have had mixed success at efforts to establish the biological affinities. One potential source of extant analogues that has been relatively unexplored is moribund algalmonocultures. We collected and sampled taxa from the UW Madison culture collection, examined and photographed them, then subjected those with evidence of possible resistant cells to acetolysis to see if recognizable remains survived. This approach of using acetolysis as "simulated fossilization" is not new, but its application to a broad array of taxa under conditions that may be expected to have forced the organisms into whatever "survival mode" they are capable of,may be. At the same time, a more targeted assortment of algal cultures with known desiccation tolerance was provided by Dr. Louise Lewis and subjected to the same treatment. Despite previous reports in the literature of resistant wall components in several of the tested taxa, only two survived acetolysis with anything beyond fragmentary or amorphous remains: Botryococcus and Protosiphon. TEM examination of these remains is ongoing. This is one approach in a multipronged study that includes field collections in the desert southwest of the US and the dry valleys of Australia in the coming year.
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1 - University of Wisconsin-Eau Claire, Biology, Eau Claire, WI, 54701
early land plants.
Presentation Type: Oral Paper:Papers for Sections
Location: Lindell C/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 2:30 PM