Q.Totipotency refers to

Totipotency is the genetic potential that every living, nucleated plant cell carries to develop into a complete individual plant when it is cultured in a suitable nutrient medium. The idea was first proposed in 1902 by the German botanist Gottlieb Haberlandt, based on his attempt to culture isolated mesophyll cells of Lamium purpureum, and it remains the single foundational principle that makes plant tissue culture possible at all - because a fully differentiated cell such as a leaf or root cell still carries a complete copy of the plant's genome, it retains, in principle, the ability to switch its developmental programme back on and regenerate an entire plant. In practice, totipotency is expressed through the paired, opposite processes of dedifferentiation (a mature cell reverting to a meristem-like, actively dividing state) and redifferentiation (those dividing cells reorganising into a new, complete plant) - it is this two-way capacity, taken together, that the book describes as totipotency. F.C. Steward's 1948 demonstration that coconut water could trigger proliferation from carrot explants is the classic direct experimental evidence for cellular totipotency, and every callus-based, embryogenesis-based or organogenesis-based regeneration technique described in this chapter is, at bottom, an application of this same underlying principle.