Inhibitory effect of diazocyclopentadiene on the development of superficial scald in Granny Smith apple

In this work, diazocyclopentadiene (DACP), an ethylene action inhibitor was used to test if ethylene is involved in the development of superficial scald of apple. Apples (Malus domestica Borkh., c.v. Granny Smith) were pre-stored at 0 degrees C for a month before DACP treatment. After treatment, fruit were stored at 0 degrees C for a further 17 weeks before being transferred to room temperature for a week. The incidence of superficial scald, contents of alpha-farnesene and conjugated triene in fruit skin were analysed. Ethylene production, respiration rate, flesh firmness and soluble solids content of fruit were determined. Results indicated that superficial scald is related to chilling injury. DACP delayed ripening, and dramatically inhibited the development of superficial scald in Granny Smith apple by lowering alpha-farnesene and conjugated triene contents. Ethylene might promote a-farnesene synthesis presumably by binding to the ethylene receptor(s).