DEVELOPMENT OF QUIESCENT CENTRES IN ROOT MERISTEMS

Summary A group of cells in the middle of the apical meristems of roots stops synthesizing DNA and dividing. This occurs during germination of the seeds in the primary roots of Sinapis, and during growth of the primordia within the cortex of the mother root in the lateral roots of Pistia and Eichornia. The first cells to become quiescent are those at the poles of the histogens of the stele and cortex. Neighbouring cells of these histogens become quiescent later on and there may be several hundred such cells enclosed within the meristem during normal growth. The neighbouring cells of the root cap remain meristematic until the whole meristem becomes quiescent.