Studies on the growth hormone of plants. V. The relation of cell elongation to cell wall formation

Abstract

Since the time of Nageli (1), increase in surface area of the plant cell wall has been frequently attributed to an active intussusception of particles of new material between particles already deposited in the cell wall framework. Intussusception formed, for example, an integral part of the theory proposed by Sachs(2) for the mechanism of growth. Nevertheless, it is undeniable that increase in cell wall material is frequently by apposition of layers of new material upon the surface of layers already laid down. Thus, even the walls of young, actively elongating cells often exhibit a distinctly lamellar structure. In cases of pure apposition, at least, increase in area must be due to processes other than active growth of the wall itself: The work of many investigators, reviewed by Heyn,(3) has indicated that increase in wall area is then by plastic stretching due to the outwardly directed pressure of the cell contents.