Growth Field and Cell Displacement within the Root Apex

Abstract

The root apex in angiosperms, structurally divided into the root proper and the root cap, consists of a coherent bundle of cell files radiating from a lens-shaped zone of cells called the quiescent centre (QC) (Clowes 1956). Located at the pole of the root proper in the region where the files of cortical and stelar cells converge, the QC houses mitotically less active cells considered as founders of the “functional” initial cells which occupy the periphery of this zone. From these initials and their derivatives the tissue of the root proper and root cap is developed (Bar-low 1994). Though factors regulating the initiation and maintenance of the QC are still being investigated (Kerk & Feldman 1995), it is commonly accepted that the QC functions as a template for cell pattern in the apex and, as a consequence of changes in QC dimensions, the pattern is altered (Feldman 1984).