Gravity is a constant stimulus governing the orientation of plant growth. In response to changes in the gravity vector, plant stems and roots bend by differential growth. We took advantage of a cold effect on the gravity response pathway to select for mutants of Arabidopsis with altered signal transduction. Physiological and molecular characterization of these mutants is ongoing.
Wood is the most important renewable natural resource.
Lignin affects the chemical and mechanical properties of many plant products and is one of the major determinants of the commercial quality of wood. However, our knowledge of major aspects of lignin biosynthesis is incomplete. A detailed knowledge of the developmental expression of the genes encoding these enzymes is needed to understand their physiological roles and to be able to manipulate lignin in a tissue or cell type specific manner. Because Arabidopsis thaliana is a more amenable system for analysis of the genes involved in wood formation, we are developing Arabidopsis as a model system to study lignification and wood production. Altered expression of calreticulin alters intracellular calcium storage and release in tobacco suspension culture cells.