Phylogeny and the evolution of succulence in the Portulacineae (Caryophyllales)

Brown University, Providence RI

Investigators

Abstract

Many plants that inhabit the arid regions of the world commonly survive by long-term storage of water in various parts of the plants. These plants are typically described as 'succulent'. Everyone knows a succulent plant when they see one, and their bizarre forms have made them popular with horticulturists and collectors. In spite of their ubiquity, scientists know very little about how extreme succulence has evolved in plants. In this project, the evolution of succulence will be investigated in a diverse lineage of ~2,000 flowering plants that include the cacti. Molecular data will be collected from ~500 species to reconstruct evolutionary relationships within the group. 'Succulence' will be characterized in quantitative terms using a newly devised measurement. Within this new framework a series of hypotheses will be tested regarding how and why succulence has evolved multiple times in plants. The project will provide novel insights into the mechanisms that have promoted drought tolerance in plants, which may help predict responses of different plant lineages to future climate change. The project will provide extensive training opportunities for post-doctoral, graduate, and undergraduate scholars, including female and minority students. The project also includes a significant public outreach effort where the PI and students will create a series of short animated films about plant evolution. These films will be designed for individuals with a high-school level biology background, and will be broadcast on the extremely popular website 'creaturecast.org'.