Joint Action of Gibberellic Acid and Coumarin in Germination

Abstract

THE stimulatory effect of gibberellic acid on germination has been recently observed^1–3 and the possible modes by which this is brought to pass have been discussed by Brian⁴. Coumarin is well known as a germination inhibitor^5,6 and is also known to induce light sensitivity in certain seeds not normally requiring light for their germination⁷. It seemed of interest therefore to determine whether gibberellic acid, like light, could reverse inhibition in coumarin treated seeds. Lettuce seeds, variety Grand Rapids, were allowed to germinate for 48 hr. at 25° C. in the dark in water, or solutions of coumarin, gibberellic acid (sodium salt), or mixtures of the two. The results are shown in Table 1.