effect of polyamines on storage life of plum fruit cv. ’shablon ‘

in this experiment, effects of three polyamines (putrescine, spermidine and spermine) on postharvest life of plum fruit cv. ’shablon‘were studied. fruit was dipped in solution of polyamines with 1 and 2 mm and distilled water (control) for 5 min in a cold storage at 1.5±0.5°c and 80-85% rh. experiment was conducted in a factorial with a complete randomized design with 7 treatments and 6 storage time with three replications. fruit firmness, titratable acidity and ph, soluble solids and weight loss were evaluated once a week. also, the rate of ethylene production was determined in three weeks, and polygalacturonase enzyme activity was measured at the first and last of storage life. polyamines reduced ethylene production significantly and was maintained the fruit firmness. the most effective treatment in maintaining the firmness was 2 mm spermine. also, this treatment was effective in preventing of ethylene production with 2 mm putrescine and 1 mm spermidine. no difference was found between the three polyamines in prevention of polygalacturonase enzyme activity. polyamine treatments were prevented fruit weight loss significantly during storage.