In Search of a Plant Growth Paradigm

Growth by cell divisions in apical meristems is mainly a synthesis of cell matter. Cell divisions in the meristem follow certain patterns, with radial gradients which may be abruptly interrupted. The gradients go in the reverse directions in stem and root apex. The cause of the gradients seems to be unknown, likewise why the patterns are the opposite in stem and root, but they form the foundation of ensuing tissue differentiation. Cell elongation is driven by the metabolic energy of intussusception of new matter in the wall and by the accepted patterns for water fluxes. An attempt has been made to formulate questions which ought to be answered for a better insight into the mechanism of longitudinal growth.