AbstractAddition of gibberellic acid to barley endosperm evokes the formation of α‐amylase and of other hydrolases. Protein synthesis inhibitors–notably cycloheximide–inhibit the production of the hydrolases and the incorporation of labeled amino acids into proteins. Isolation, purification, and “fingerprinting” of the gibberellic acid‐induced α‐amylase indicate that it is formed byde novosynthesis. RNA synthesis inhibitors–notably actinomycin D–also inhibit the production of α—amylase and of the other hydrolases. Gibberellic acid enhances the incorporation of labeled RNA precursors into RNA. These data are consistent with the idea that gibberellic acid controls the level of α‐amylase and of other enzymes by controlling the synthesis of specific RNA's which in turn control the synt