Presence of Gibberellin-like Substances in Lettuce Seed

Abstract

GIBBERELLINS and gibberellin-like substances are being shown to occur in an increasing number of higher plants. Immature seeds of numerous species contain particularly large amounts of these substances¹, but the levels in mature seeds of the same species are much lower². Certain seeds respond very strongly to applied gibberellin, this being particularly evident in certain ‘light-requiring’ seeds, for example, those of lettuce^3,4 and Arabidopsis thaliana ⁵, in which gibberellin treatment may result in complete germination in the dark. The obvious first step towards understanding the physiological significance of this gibberellin action is to determine whether gibberellin-responsive seeds contain endogenous, gibberellin-like growth regulators. The present communication reports on such studies with mature seeds of lettuce (Lactuca sativa L.).