Action of Gibberellic Acid on Lettuce Seed Germination

Abstract

Several workers have shown that gibberellic acid (GA3) promotes the germination of seeds which ordinarily require light (6, 10, 13, 14, 16, 17, 23, 28, 30). This phenomenon raises several fundamental questions as to the mechanism of light-controlled germination: A: Does light simply act by releasing a gibberellin in the seed, B: Does the GA3 substitute for light by bringing about chemically a reaction which is normally photochemical, or C: Does the GA3 bring about some quite other type of growth process which independently leads to germination? The following experiments are an attempt to provide answers to these questions.