Julie R. Etterson, Ph.D. - US grants

Anthropogenic climate change will alter patterns of natural selection and pose strong evolutionary challenges to wild organisms. Plant species that have experienced genome doubling, or polyploidy, may have an advantage over those possessing a single copy of the genome because they can evolve faster or in novel directions in response to climate change. Examination of the creative role of polyploidy is important given that genome duplication is thought to have occurred in 47%-70 % of flowering plant species. This research will test the evolutionary potential of polyploids by imposing artificial selection for increased drought tolerance in a polyploid species (goldenrod, Solidago altissima) that varies naturally in chromosome number (2, 4, and 6 copies). The central hypothesis of this research will be supported if plants with higher chromosome numbers evolve faster in response to artificial selection.

This work will provide a large number of students with intensive hands-on training in lab and field techniques and provide opportunities for independent research at the graduate and undergraduate level. This research fulfills the objectives of the RUI program by addressing a question of great interest to society, the impact of climate change, and by providing solid training to a diversity of students who will become the next generation of scientists.

Climate change will alter key aspects of the environment for plants, such as temperature and water availability. Very little is known about how plants will contend with these changes, particularly species that are difficult to study, such as long-lived tropical trees. This project examines short-term physiological responses and the potential for long-term evolutionary changes in response to experimental manipulations of precipitation in populations of a tropical oak species that occur in different climates in Central America. The project investigates the extent to which these populations are adapted to the climate they currently experience and their potential response to climates that are similar to those predicted for the future. New insights will be gained as to whether impacts of climate change at the seedling stage enhance or constrain adaptation at later life stages of the tree. In addition, the research will identify the physiological and genetic mechanisms that enhance or limit adaptation to altered climates in this tropical tree. The project fosters the education, mentoring, and training of undergraduates, doctoral students, and a postdoctoral associate in plant ecological physiology and quantitative genetics at the University of Minnesota and at the University of Zamorano (Honduras). This work offers unique training and mentoring opportunities for Latin American undergraduates and para-taxonomists in Honduras and Costa Rica. It will also develop a collaborative, interdisciplinary network between researchers at the University of Minnesota, Cornell University, the University of Zamorano in Honduras, the Area de Conservacion Guanacaste in Costa Rica, and the Center for Ecosystem Studies (CIEco-UNAM) in Mexico.