This award will support a U.S.-Japan Cooperative Photoconversion/Photosynthesis Research Program project between Professor Judith Croxdale, Department of Botany, University of Wisconsin, and Professor Kenji Omasa, Environmental Plant Science Section, National Institute for Environmental Studies, Tsukuba, Japan. The project involves cooperative experiments to examine whether, in the mesophyll of developing dicot leaves, new cells that arise at multiple sites are coordinated by their position in the developing leaf or by their cell lineage. The question is one of fundamental importance to plant developmental biology. The function of clones in developing leaves will be studied by monitoring photosynthesis. The development of the photochemical apparatus will be determined by repeatedly imaging the kinetics of chlorophyll a fluorescence in the clones. Uniform function within clones throughout their development will indicate regulation by cell ancestry, while heterogeneity within clones will indicate the participation of other influences in the development of cellular function. Clones intersected by vascular tissue will be particularly useful in assessing the contributions of other cell types on mesophyll differentiation. Since the clones created will span the entire period of leaf development, the investigators can determine if there are "windows" during development when ancestry may control function, and other times when positional information may regulate cellular development.
