The proposed study uses the available ligule-specific mutants to ask how polarized cell divisions are regulated. The goal of the study is to test the hypothesis that the cytoskeleton plays a structural role in the transmission of the genetic information that directs cell division. The hypothesis will be tested characterizing the cytoskeletal changes of normal and ligule-specific mutants using immunocytochemistry of intact and sectioned leaf tissue. Micromanipulation of leaf primordia will test for the time of determination of the ligule, and inhibitor experiments will test for the role of specific cytoskeletal components. The time of DNA synthesis, as determined by autoradiography, will place the cytoskeletal changes within the context of the cell cycle. Since ligule division is precise and predictable, a comparative study with mutant plants will provide a means to isolate specific control points during division. These results will clarify the process by which the cytoskeleton participates in the establishment of cell polarity during division. In order to completely understand the mechanistic events which result in an ordered program in the developing organism, it is necessary to use the techniques of genetics, cell biology, biochemistry, etc. Too often, however, the several binds of expertise are not available to a single laboratory and the combined approach is not used. This project brings together genetics and cell biology to ask a significant developmental question. If the cytoskeleton is implicated as a conduit of genetic information in the cell by this study, the impact will be felt in all aspects of biology, not just the area of plant biology.
