Changes of both insoluble carbohydrates and RNA are described in the root apical meristem of Ceratopteris thalictroides (L.) Brongn. The apical cell exhibits more carbohydrate granules than its neighboring cells in the actively growing root. It is almost missing in the apical cell of the old root. There are no marked differences in RNA content between the apical cell and its derivatives in both young and old roots. The division role as well as their physiological roles of the apical cell, based upon the high amount of insoluble carbohydrates in the growing root, compared to the low amount in old root, were discussed.