ABSTRACT
Much of the evidence for the extension of the models to plant systems has come from research on cytokinin-induced cell division and bud formation in target caulonema cells of mosses and research on cytokinin effects on calcium status of other cytokinin-responsive systems. To understand how a quiescent cell can translate a rise in Ca2+ into a series of events culminating in mitosis, it is necessary to look at the regulation of Ca2+. The role of calmodulin (CaM) in the regulation of the cell cycle and mitosis remains to be established. CaM has been localized in the spindle, and a role in microtubule depolymerization during chromosome motion to the poles has been postulated. The effects of calcium on a cell may be dependent on the state of the cell and/or the duration of the signal. Triggering the common development event of mitosis may occur in some cells as the result of a Ca2+ transient.
