Life Sciences and Biotechnology Building 2419
The Evolution of Plant Mating Systems. Our work explores the extraordinary diversity of plant mating systems, the selective factors that shape that variation, and the role that mating systems play in limiting gene flow between species.
Hybridization and Cleistogamy in Triodanis. Two subspecies of Triodanis perfoliata (Venus’ looking glass), a weedy annual plant, provide an opportunity to address questions concerning the evolution of cleistogamy and its role in determining patterns of gene flow. Cleistogamy refers to the production of modified flowers that do not open and therefore produce seeds solely by self-fertilization. Two subspecies that co-occur throughout our region differ in their allocation to cleistogamous (closed) and chasmogamous (open) flowers. Through field, greenhouse and genetic marker approaches, we are looking at the effects of allocation to each flower type on reproductive success and on the potential for hybridization.
Evolution of self-compatibility in Leptosiphon. I have a long-standing interest in the ecological and genetic factors that play a role in the evolution of self-fertilization from self-incompatibility – a genetic mechanism that allows a plant to recognize and reject its own pollen to promote cross-fertilization. Leptosiphon jepsonii, a California annual species, has an unusual and variable breeding system that provides us with a unique opportunity to study the breakdown of self-incompatibility. The flowers of most L. jepsonii plants are initially self-incompatible, becoming capable of selfing later in anthesis; other plants are self-compatible when flowers first open. The frequency of these different phenotypes ranges widely among populations, allowing us to explore how outcrossing rate, inbreeding depression, reproductive assurance and other parameters are correlated with variation in self-compatibility.
Long-term Ecological Studies of a Wetland Plant Community. Supported by NSF funding, this project was designed to involve undergraduate biology students in authentic ecological research at realistic spatial and temporal scales.
Experiment history and design. We are studying the long-term effects of nutrient addition and disturbance on a plant community at a site near the ECU campus. In nine years of study, we have observed significant decreases in diversity in fertilized and unmowed plots, and changes in the relative abundance of forbs, grasses and woody species.
Evolution in ecological time. We are developing tools to test for adaptive evolution and changes in population genetic structure in response to the experimental treatments. We are generating AFLP genetic markers and developing greenhouse cultivation methods for target plant species that are present throughout the long-term ecology plots, including Euthamia caroliniana (slender goldentop) and Packera tomentosus (woolly ragwort).