Floral evolution in the genus Conophytum (Aizoaceae) in South Africa

• Applicant: Professor Dr. Andreas Jürgens
• Subject Area: Evolution and Systematics of Plants and Fungi
• Term: from 2002 to 2007
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5362685

Compared to all other genera of the Aizoaceae the genus Conophytum has a remarkable high number of night-flowering species. About 1/3 of the c. 90 species are described as nocturnal. Nocturnal Conophytum species are known for their well-scented flowers (Hammer 1993). The floral scent composition of nocturnal Conophytum species seems to represent two groups: First, the section Conophytum with species having compounds clearly indicating moth-pollination, and second, the sections Cheshire-Feles, Costata, and Saxetana, with scent compounds typical for species with a more generalistic pollination system (A. Jürgens in press). It is striking that this differentiation in scent compounds is consistent with the distribution of the species. Species from the Cape Floristic Region, (N. Jürgens 1991), seem to be more specialized for moth-pollination. This raises the questions whether patterns of chemical variation of floral scents are a result of an adaptation to different pollinators or due to phylogenetic constraints. An analysis of the floral scent composition, pollinator observations, as well as RAPD and AFLP analyses will be used to answer thes questions. Because in the last years the genus Conophytum has been studied by many hobbyists there is much information on the population level. As stated by Hammer (1993) c. 1800 populations are known. This amount of information makes the genus an ideal model for studying radiation and diversification. A database management system (available via internet) will be established for connecting internal and external sources of data on plant locations, floral scent compounds, and the molecular phylogeny of the genus.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1127: Radiations - Origins of Biological Diversity