DISSERTATION RESEARCH: Predicting Plant Life-Cycles in Changing Environments

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A critical goal in ecology is to predict how organisms will respond to altered climate. Since responses to temperature differ at different stages in the development of most plants and animals, one must investigate these responses in each life stage. For plants, the environment that each life stage is exposed to is determined by the timing of germination, reproduction, and seed dispersal. Plants can use environmental cues such as temperature, moisture, and day length to time these developmental transitions so that life stages occur during favorable times of year. For example, temperature during seed maturation can influence the level of seed dormancy, and the timing and duration of seed maturation can determine the seasonal conditions during seed dispersal. However, little is known about how the environment during seed development affects plant life cycles. This project will provide empirical estimates of the environmental sensitivities to temperature of seed dispersal, dormancy, and germination in the plant Arabidopsis thaliana, and incorporate these estimates into linked models to predict when a plant will be in each of its life stages when exposed to a particular regime of temperature. Experiments in the field and in growth chambers will characterize how variable temperatures during seed maturation alter dormancy level, levels of gene expression of a key dormancy gene, and the timing of seed dispersal. The experiments will provide critical information on the least understood phase of the life cycle of annual plants. Integrating these data into the life-cycle model will improve predictions of organismal responses to changing climates.This research is important to society because accurately predictions of life-cycle timing in plants will be necessary to anticipate the ecological consequences of global warming, and to manage weeds and other invasive species as plant ranges expand across landscapes. The project will also contribute to the scientific training of a Ph.D. student and three undergraduate, and to educational outreach through the creation of an interactive teaching module for undergraduate and high school students.