THE DETERMINATION AND UTILIZATION OF GIBBERELLIC ACID IN GERMINATING BARLEY

A barley endosperm bioassay, utilizing the induction of acid phosphatase in barley endosperm seed halves, has been developed and applied to study both the development of endogenous gibberellin in grain germinating under malting conditions and the utilization of externally applied gibberellic acid. The assay is affected by barley age and variety and these observations may have practical implications. After 24 h germination the level of endogenous gibberellin-like material present in the grain was approximately 1·4 ng/corn. The biological activity of the total gibberellin-like material extracted from grain treated with gibberellic acid fell during germination although significant quantities of applied gibberellic acid had entered the grain during the first 24 h germination.