PEROXIDASE AND IAA OXIDASE ACTIVITIES AND PEROXIDASE ISOENZYMES IN THE PERICARP OF SEEDED AND SEEDLESS REDHAVEN PEACH FRUIT

Parthenocarpic peach fruit (Prunus persica L. Batsch., cv. Redhaven) w ere induced with 1-(3-chlorophthalimide)-cyclohexane carboxamide (AC 9 4377). The activities of soluble, and ionically and covalently bound p eroxidase and indole-3-acetic acid (IAA) oxidase in the pericarp of bo th seeded and parthenocarpic fruit were determined from 21-43 days aft er anthesis. Seedless fruit grew faster during early stage I and cease d growth earlier than seeded fruit. Total peroxidase and IAA oxidase a ctivities increased with development on both types of fruit, but highe r values were found in seedless fruit. The ionic fraction showed the g reatest increase for both enzyme activities. Isoperoxidase profile sho wed new cationic isoenzymes and higher levels of the less anionic isoe nzymes in the pericarp of seedless fruit, whereas the seeded fruit con tained higher levels of the more acidic isoperoxidases.