Capacity of higher organism cell to differentiate into entire organism, totipotent cell contains all genetic information necessary for complete development.
When an explant from differentiated tissue is used for culture on a nutrient medium, the non-dividing quiescent cells first undergo certain changes to achieve a meristematic state. The phenomenon of the reversion of mature cells to the meristematic state leading to the formation of callus is called “dedifferentiation”. The component cells of the callus have the ability to form a whole plant a phenomenon described as “dedifferentiation”. These two phenomenons of dedifferentiation and “redifferentaition” are inherent in the capacity described as “cellular totipotency”, a property found only in plant cell and not in animal cells. In other words, while a differentiated plant cell retain its capacity to give rise to whole plant, an animal cell loses its capacity of regeneration after differentiation. Although, generally a callus phase is involved before the cell can undergo redifferentaition leading to regeneration of whole plant, but rarely, the dedifferentiated cells give rise to whole plant directly without an intermediate callus phase.