Exogenous polyamines and gibberellic acid effects on peach (Prunus persicaL.) storability improvement

Peaches (Prunus persica L., cv. Babygold 6) harvested at the stage of comme rcial ripening were pressure-infiltrated with putrescine (1 mM) or GA(3) (1 00 mg L-1) and then stored at 2 degrees C for 14 d. Both treatments increas ed fruit firmness, putrescine-treated peaches being significantly firmer th an control ones. Treatments were also effective in reducing the susceptibil ity of the fruit to be damaged by mechanically compression with lower volum e and surface of the damage zone. Ethylene emission and the respiration rat e were reduced in treated fruits, which reflects a delay of the ripening pr ocess. The effects of the mechanical stress could be related to increased s permidine levels, rather than ethylene emission and respiration rate during storage.