Changes in Abscisic and Phaseic Acids during Ripening and Senescence of Peach Fruits

Changes in contents of abscisic acid (ABA) and phaseic acid (PA) of peach fruits were examined during post-harvest ripening and senescence.1. Immediately after harvesting, the content of ABA in peach fruits was 0.12μg per g. of fresh weight. Its content increased to maximum 4.20μg/gFW) after 5 days in storage at 20°C. The presence of two isomers (cis- and trans forms) ABA was confirmed by GLC and GLC-MS and their contents were determined by an internal standard method. The results indicated that most of the increased ABA during ripening was trans-isomer.2. Phaseic acid, which is known as an ABA-like bioactive compound among some ABA-metabolites, was detected in peach fruits. The content of PA in the fruits increased with proceeding of ripening and senescence. A correlation between the increase of PA content and softening of the peach flesh may involve a certain participation of PA in the softening process of peach flesh (ripening and senescence).