According to Quiescent Centre Theory, root apical meristem is present as the tip of main root and has a biconvex quiescent centre in its centre which is characterized by presence of inactive cells with less number of cell organelles, light cytoplasm, small nuclei and low synthesis of DNA, RNA and protein caused by low frequency of cell division, mitosis. Related Theory Behind the root cap is the quiescent centre. a region of inactive cells. They function to replace the meristematic cells of the root cap meristem. The quiescent centre is also important in organizing the patterns of primary growth in the root.