This research will exploit a unique developmental system (in which mesophyll cells of Zinnia elegans differentiate in suspension culture to form tracheary elements with distinctly patterned secondary walls) in order to obtain a more integrated view of how higher plant cells initiate and control the deposition of a patterned wall. Five major areas of reserach will be conducted to meet this goal: (1) Light and electron microscopy to clarify the timing and cytology of differentiation; (2) Investigation of the role of microtubules; (3) Investigation of the role of microfilaments; (4) Investigation of the role of the Golgi apparatus and the functional life of rosettes (particles associated with cellulose synthesis) in the plasma membrane; and (5) Investigation of calcium.mediated events critical to the initiation and continuation of differentiation. Light and electron microscopy (coupled with immunochemical and cytochemical probes) will be used to monitor changes in differentiation.related cellular processes before and after application of antagonistic drugs. The results of this study will increase our knowledge of how diverse cellular features function together in the control of a well.defined developmental event. They will also enhance our understanding of the control of plant morphogenesis, which is partly determined by the pattern of microfibrils in cell walls.
