Differentiation, De-Differentiation, Re-Differentiation

a. Differentiation : Cells derived from the apical meristem of the root or shoot mature into their final, functional form. This permanent change in the structure and function of a cell, which brings it to maturity, is called differentiation. It can involve minor to major anatomical and physiological changes -- for example, parenchyma cells in hydrophytes develop large schizogenous air spaces that provide mechanical support, buoyancy and aeration. Differentiation is achieved at the cost of the cell's ability to divide further.

b. Dedifferentiation : A living, differentiated cell that has lost the capacity to divide can, when required, regain that capacity and begin dividing again -- this reversal of maturity back to a meristematic state is dedifferentiation. For example, interfascicular cambium and cork cambium both arise from parenchyma cells (located between vascular bundles, and in the innermost layer of the cortex respectively) that have dedifferentiated. …