The core of this study involves the characterization of leaf developmental mutants in maize. Two have been cloned via transposon-tagging. The questions addressed in this proposal are: 1.Are the leaf development mutants under study altered in cellular age-identity, as hypothesized, or in position-identity? Problems of developmental time-keeping are especially approachable in plants. 2. Does the animal concept of developmental compartments apply to plants? Dr. Freeling will address this question using a dominant dwarf in genetic mosaic studies. 3. Are the provascular cells the primary inducers of other leaf cell fates? Is the epidermis an information "blank sheet" until induced to differentiate into particular cell types? Dr. Freeling will approach these two related question using detailed vein lineage maps, periclinal chimeric analyses, and mutants that fail to anastomose intermediate veins. %%% These studies will establish the maize leaf as a powerful developmental system amenable to mutant analysis as well as for cell biological, and embryological studies. The approach to the mutants at these levels will provide a context for the on-going studies on the molecular descriptions of developmental gene regulation.
