Occurrence of Substances Similar to Gibberellic Acid in Higher Plants

Abstract

IF the fungal metabolite gibberellic acid is applied to dwarf varieties of pea, french bean (Phaseolus), broad bean (Vicia) or maize, growth is greatly accelerated and plants similar to the normal tall phenotype are produced; the tall varieties themselves are much less affected by gibberellic acid, if at all^1,2. This suggests that this acid, or a substance with similar physiological properties, is a normal plant-growth regulator, produced less abundantly in dwarf varieties than in tall ones. The growth-promoting substance obtained from immature bean seeds by Mitchell, Skaggs and Anderson³ was probably of this type; more recently, West and Phinney⁴ have reported the probable occurrence of substances like gibberellic acid in seeds of several plant species; I have obtained evidence of such a substance in the shoots of dwarf and tall peas, and this is summarized below.