‘Bound’ Gibberellin in Mature Runner Bean Seeds

Abstract

RADLEY¹ has mentioned the possibility that gibberellins occur in the tissues of higher plants in both ‘free’ (readily extractable) and ‘bound’ forms. By analogy with plant-growth regulating substances of the auxin type, the hypothetical ‘bound’ gibberellins might be liberated by the hydrolysis of proteins of the plants being investigated. This communication describes one of several experiments in which more ‘gibberellin-like’ activity was detected in hydrolysed than in non-hydrolysed extracts. Radley¹ has observed that the level of readily extractable gibberellin of the seeds of the runner bean (Phaseolus multiflorus) falls as the seeds mature. One could visualize that the gibberellin is becoming ‘bound’ in some way as maturation proceeds, and because of this possibility seeds of the runner bean were chosen for investigation.