Collaborative Research: Generic Relationships within Subfamily Bromelioideae (Bromeliaceae)

Hope College, Holland MI

Investigators

Abstract

A grant has been awarded to Dr. Brown at the University of Wyoming and Dr. Evans at Hope College to examine evolutionary relationships among members of the tropical plant family Bromeliaceae subfamily Bromelioideae. The Bromelioideae, with 30 genera and about 750 species, is the most poorly understood subfamily in Bromeliaceae. Almost a third of the species in subfamily Bromelioideae are represented by the genus Aechmea, an extremely variable, and almost certainly artificial genus. Several genera in Bromelioideae differ from Aechmea by only one or two characters, and the morphological boundaries among genera are very poorly defined. Aechmea forms the core of a complex of as many as 20 Bromelioideae genera for which evolutionary relationships and systematics are in complete disarray. The primary goal of this project is to utilize morphological and molecular (DNA sequence) data to examine relationships within Bromelioideae, with an emphasis on Aechmea and closely related genera. Morphological information from individual plants will be collected during intensive field studies. Because floral characteristics are poorly preserved in this family during the normal pressing and drying process, observation of live and/or liquid preserved material is critical for successful phylogenetic analysis. Phylogenetic analyses using maximum-parsimony methods will be conducted on the taxon by character data matrices produced in this intensive reanalysis of morphology. DNA sequence data from three non-coding regions (two chloroplast intergenic spacers, psbA-trnH and trnL-trnF, and nuclear ribosomal internal transcribed spacer regions) will be collected from the same individuals used for morphological studies. Phylogenetic analyses of the molecular data will provide an independent assessment of the morphological phylogenies as well as a tool to examine the evolution of specific morphological characters. Integration of multiple data sets is currently an area of much discussion and debate in systematics, and several methods for comparing and integrating the molecular and morphological data will be explored. The proposed research will contribute significanly to several broader sceintific and educational goals, as follows: 1) It represents the first attempt to develop hypotheses of phylogenetic relationships within Bromeliaceae subfamily Bromelioideae from within an explicit phylogenetic paradigm. 2) It will make a significant contribution to biodiversity documentation for an ecologically important taxon (Bromelioideae) in one of the most endangered, yet biotically diverse biomes on Earth, the Atlantic Forest Biome of Brazil. 3) Ecologically, tank-forming bromeliads, which include most members of Bromelioideae, are keystone species in biodiversity maintenance. They are an important resource for free-water in the canopy, and provide feeding sites, breeding sites, and habitat for many diverse organisms that represent all Kingdoms of life. The resulting phylogenetic hypotheses will be important to biologists studying diversification, biogeography, and possible co-evolutionary patterns of any of the organisms that utilize bromeliad tanks. 4) Both U.S. and Brazilian students will be trained in modern systematic practice and theory. 5) The project will improve professional botanical systematics research and teaching infrastructure at an important Brazilian university. 6) DNA samples and sequences collected will be made available to other researchers. 7) The project will help to stimulate future collaborative U.S. - Brazil systematic and biodiversity-related research and education.