Growth Substance (Auxin) in Plants

Abstract

ADVANCES in the botanical study of growth substances have recently been made in several laboratories, but the present paper is more especially concerned with the work of the Utrecht Laboratory. Brief mention is made of Heyn's investigations in Paris and in Leeds on the influence of auxin on the extensibility of the cell walls of oat seedlings, where he could distinguish between the plastic and the elastic extension. This work affords an explanation of the differences of elastic extensibility, which occur as a result of changes of the rate of elongation. These experiments are carried out at Utrecht, more especially the X-ray investigations.