Increased ethylene biosynthesis elevates incidence of chilling injury in cold-stored 'Amber Jewel' Japanese plum (Prunus salicina Lindl.) during fruit ripening

P>Mature 'Amber Jewel' Japanese plum fruit were stored at 0 or 5 degrees C for 3 and 6 weeks to investigate their effects on ethylene (C2H4) biosynthesis during ripening at ambient temperature in the development of chilling injury (CI) and fruit quality. CI (internal breakdown and browning) and fruit softening were higher during ripening, in the fruit stored at 5 degrees C than 0 degrees C, irrespective of storage period (SP). C2H4 production and activities of 1-aminocyclopropane-1-carboxylic acid synthase (ACS) and 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) enzymes, and 1-aminocyclopropane-1-carboxylic acid (ACC) content were higher during ripening in fruit stored at 5 degrees C than 0 degrees C. The fruit stored at 5 degrees C also exhibited higher respiration rate and higher soluble solids concentration/titratable acidity ratio. In conclusion, increase in storage temperature and SP elevates the activities of ACS and ACO enzymes and consequently C2H4 production which leads to the development of CI in plum fruit with advancement of ripening.