PHENOLIC COMPOUNDS AND TOTAL SUGAR CONTENT IN 'ORO AZTECA' PEACH FRUIT SPRAYED WITH PUTRESCINE

Three doses of putrescine: 0, 2.5 and 5 mM were applied on ‘Oro Azteca’ peach (Prunus persica L. Bastch.) trees 15 days after full bloom (DAFB). Until 60 DAFB, the content of phenolic compounds in the fruit treated with 5 mM putrescine was 15-40% higher than those in the other two treatments. Higher phenolic compound content was observed at 19 and 60 DAFB, corresponding to 0.37 and 0.40 mg g^-1 fresh weight (FW), respectively. At 19 DAFB, total sugar content in the fruit treated with 5 or 2.5 mM putrescine was approximately 20 mg g^-1 FW higher than that in the un-treated control. The higher levels of phenolic compounds and total sugar might suggest more intensive metabolic activity during the early fruit growth. At harvest, 2.5 mM putrescine-treated-fruit had higher levels of total sugar content and when these fruits were stored for 14 days at room temperature, they exhibited 32% weight loss. However, 5 mM and 0 mM putrescine-treated-fruit displayed 40 and 47% weight loss, respectively.