INHIBITION OF ETHYLENE PRODUCTION AND 1-AMINOCYCLOPROPANE-1-CARBOXYLATE OXIDASE ACTIVITY BY TROPOLONES

The effect of tropolone and hinokitiol on C2H4 production and in vitro ACC oxidase activity was examined by using apple fruit plugs. Applica tion of aqueous tropolone and hinokitiol solution inhibited C2H4 produ ction, but the addition of Fe2+ in the solution alleviated the inhibit ion. Gaseous tropolone and hinokitiol were also effective in suppressi ng C2H4 production, but the suppression was annulled when apple plugs were pretreated with Fe2+. Tropolone and hinokitiol inhibited in vitro ACC oxidase activity, which was recovered by adding Fe2+ in the assay medium. Therefore part of inhibition of C2H4 production by these trop olones was due to their chelating action of Fe2+, which is essential f or the activation of ACC oxidase. (C) 1998 Elsevier Science Ltd. All r ights reserved.