Experimental control of the activity of the quiescent centre in excised root tips of Zea mays.

Quiescent centres have been demonstrated in cultured excised root tips of both Pisum sativum and Zea mays. Upon addition of sucrose to Zea roots which have been deprived of carbohydrate, the cells of the quiescent zone as well as those of the rest of the meristem undergo DNA synthesis. Following the onset of proliferative activity in the meristem, DNA synthesis in the quiescent-centre cells is again arrested. It is suggested that the dividing cells of the meristem are responsible for the maintenance of the quiescent centre. It has also been shown that DNA-synthesising cells do occur within the quiescent centre and that they appear to be localised in specific regions.