Effect of n-Propyl Dihydrojasmonate and Abscisic Acid on Oxygen Radical Scavenging Enzymes in Chilled Persimmon Fruit (Diospyros kaki cv. 'Nishimurawase')

Persimmon is a chilling susceptibility fruit. In this study, two plant growth regulators n-propyl dihydrojasmonate (PDJ) and abscisic acid (ABA) were applied to persimmon fruit (Diospyros kaki cv. 'Nishimurawase') to investigate their effect on oxygen radical scavenging enzymes and chilling injury (CI) development during low temperature storage. Fruit at commercial maturity were thoroughly sprayed with PDJ or ABA at 250 ppm, and then stored at 0 degrees C for 8 weeks. Thereafter, they were transferred to 25 degrees C for 2 days to ripen. Both PDJ and ABA induced ethylene production in treated fruit. PDJ treatment effectively reduced CI symptoms as evidenced by less-grayish peel browning. The activity of oxygen radical scavenging enzymes, namely catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX) in the PDJ treatment were higher than those of the control fruit. There was no difference between ABA and control fruit.