Poster: Evolution

Abs # 787: The Hawaiian Islands: a model environment for molecular studies of flower and fruit evolution

Presenter:	Albert, Victor A., victor.albert@nhm.uio.no
Authors	Albert, Victor A. (A)   Lindqvist, Charlotte  (A)
Affiliations:	(A): Natural History Museums and Botanical Garden, University of Oslo, Norway

The Hawaiian Islands, with their extreme isolation and young geological age, provide an ideal setting for comparative research on the processes underlying plant reproductive evolution. Although many Hawaiian plant groups display considerable morphological diversification, these radiations are usually contrasted with poor genetic divergence. Several examples of in situ evolution of novel reproductive features have been discerned from the limited phylogenetic studies available. Breeding system (hermaphroditism to dioecy) and pollination syndrome (biotic to wind) evolution have been studied phylogenetically in the endemic Alsinoideae (Caryophyllaceae). The evolution of bird-pollination is known among other endemics, e.g., the mint genus Stenogyne (Lamiaceae) and species of Geranium (Geraniaceae) and Hibiscadelphus (Malvaceae). Floral homeosis is known in the endemic genus Clermontia, of which 2/3 of species have a second whorl of petals completely replacing sepals. Earlier research has demonstrated expression of a PISTILLATA ortholog in whorl 1 of such species. Clermontia and some other Hawaiian lobelioids (Campanulaceae) bear fleshy berries, whereas the ancestral state is dry capsules. Stenogyne and Phyllostegia (another Hawaiian mint genus) also bear fleshy fruits, rather unlike their dry-fruited Hawaiian endemic relatives or their ancestral lineage. Finally, superior ovaries have evolved inside the endemic genus Tetraplasandra, a member of an otherwise epigynous angiosperm family (Araliaceae). These recent reproductive shifts could provide excellent systems for comparative molecular studies of morphological ‘macro’evolution. Supported in part by The Floral Genome Project, NSF DBI-0115684.