Quiescent centre concept in conern of root apex organization was proposed by Clowers $(1961)$, According to which, a region called quiescent centre is found below the root cap. It is a zone of inactive cells that act a reservoir of cells and used when other meristematic cells are damaged.
The sequence of growth and division of a cell, and consists of a series of biological processes, particularly the resting phase (G0), the interphase (G1, S, G2), and cell division (i.e. mitosis and cytokinesis)