Current interest centers around the role of calcium, membranes and the cytoskeleton in cell division and development. Particular attention is being given to the occurrence of fluxes and/or gradients in the calcium ion concentration. Using high resolution ion imaging, we are attempting to elucidate the timing, location, and magnitude of calcium ion gradients, and to decipher their role in controlling plant cell division and growth. During mitosis, for example, we are specifically examining the role of calcium in regulating the formation of the cell plate during cytokinesis. For cell growth we are focusing on the presence and oscillation of apical ion gradients in tip growing pollen tubes and root hairs.