Enhancement of Gibberellic Acid Sensitivity in Corn (Zea mays) by Fluridone and R-40244

Fluridone {1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4 (1H)-pyridinone} and R-4-0244 [1-(m-trifluoromethylphenyl)-3-chloro-4-chloromethyl-2-pyrrolidone], herbicides that block carotenoid synthesis, increase the sensitivity of corn (Zea maysL. ‘Merit’) to exogenously-applied gibberellic acid (GA). Increase in shoot length due to the application of GA to imbibing corn seeds was considerably enhanced by simultaneously applying either fluridone or R-40244. Fluridone was more active in this respect than R-40244.