BOYKIN, LAURA*, TIMOTHY LOWREY, and WILLIAM POCKMAN. Department of Biology, The University of New Mexico, Albuquerque, New Mexico, 87131. - Ecology and Evolution of Orcuttieae (Poaceae): An Endangered Vernal Pool Grass.
The purpose of this project is to: 1) reconstruct a phylogeny for
Orcuttieae, a small tribe of vernal pool C4 grasses, using
molecular data and 2) use the phylogeny to assess the evolutionary
history and pathway modifications of C4 photosynthesis in
this group. Previous work by Keeley (1998) revealed that
Orcuttia carries out C4 photosynthesis in aquatic
leaves but lacks Kranz anatomy while the remaining genera in the
tribe, Tuctoria and Neostapfia have Kranz anatomy.
Keeley (1998) proposed that Orcuttia is the most derived genus
in the tribe followed by Tuctoria and the earliest derived
genus Neostapfia. His hypothesis was based on the lack of Kranz
anatomy and other aquatic adaptations. This investigation will test
the hypothesis advanced by Keeley (1998) to explain the unique
physiology of the Orcuttieae. A phylogeny coupled with the
photosynthetic data for this group will elucidate the transition of
Orcuttieae from land to an aquatic environment.
Key words: Kranz Anatomy, Molecular Evolution, Orcuttieae, Photosynthesis, Poaceae, Vernal Pools