The physiology of cell elongation

Abstract

The phenomena of growth may be separated into different processes, such as differentiation, elongation and maturation. Of these, only cell elongation will be dealt with in the following pages. The term elongation will be used for any permanent enlargement of cells already formed by differentiation. As the size of a plant cell is determined by the extent of the surface of its wall, cell elongation may be defined also as any permanent increase in the surface of the cell wall. Although elongation was studied by the earlier botanists, analysis of its mechanism had not yet been made some few years ago, and the views of different authors at that time differed widely. Almost every theoretical possibility was formulated into a theory. The question as to which factor initiates elongation, and which of the many properties and factors, playing parts during or varying with elongation, is the primary and direct cause of elongation and its limiting factor, could not be answered with certainty. Before considering contemporary ideas on the subject, a short survey of the different views of older investigators will be given, thus providing a clearer introduction to the problem, and some definitions will precede this survey in order to prevent misunderstanding: