Interactive effects of key components of global climate change on plant growth and development

Exploring plant responses to multiple co-occurring environmental factors is critical for a better understanding of how these factors affect plant production and seed development in the future. Although plants in nature are subject to multiple factors, most studies have considered only one factor at a time. The overall goal of this research program is to investigate the underlying mechanisms of plant responses to multiple environmental factors, associated with climate change. We hypothesize that plants respond differently to single and interacting environmental factors during vegetative and reproductive stages, and abscisic acid (ABA) is a key endogenous factor that serves as an important signaling molecule that enables the plant to generate protective responses to changing environments. We use three plant species from the family Brassicaceae: canola, stinkweed and Arabidopsis. Canola is a significant agricultural crop in Canada. Information on how it responds to the changing environment will be important to Canadian agriculture. Changes in the growth dynamics of weeds are also important to agriculture, as aggressive growth of weeds reduces yield of food crops. Stinkweed is selected for its wide distribution and local presence in Nova Scotia. Arabidopsis is selected because of its well-known responses to single stress factors and the large number of well-characterized mutants that vary in response to ABA. Mutant-based approach allows us to focus on specific questions at the biochemical, physiological or anatomical levels, and gain a mechanistic understanding of the process. The objectives of the proposed research are (1) to examine the single and interactive effects of CO2, temperature and watering regime on plant growth and development during vegetative and reproductive stages, (2) to elucidate the effects of these environmental factors on plant reproductive yield, (3) to determine the importance of ABA in plant responses to single and interactive factors during vegetative and reproductive stages, and (4) to explore ABA regulation of seed development and dormancy under co-occurring factors. The results should provide us with mechanistic understanding of plant responses to multiple environmental factors, and benefit Canada's agricultural industry.*