Active oxygen-scavenging enzymes activities in developing apple flowers and fruits

Abstract

The activities of active oxygen-scavenging enzymes, superoxide dismutase, catalase and peroxidase were evaluated during apple ( Malus domestica Borkh cv. Red Spur Delicious) flower bud and fruit development. In dormant buds, superoxide dismutase, peroxidase and catalase activities were initially low, then increased sharply (2- to 5-fold) during bud swelling. With onset of bud break and during fruit development, superoxide dismutase and peroxidase activities decreased by 5- to 8-fold, while catalase activity remained relatively high throughout flower bud development and during early stages of fruit growth, before declining at full fruit development. A second increase in peroxidase activity occurred at full fruit development. In immature and mature fruits, superoxide dismutase activity was detected only in the peel, but not in cortex (flesh) or in seed tissue. Peroxidase activity was highest in peel, low in cortex and absent in seed tissue. Catalase activity was highest in seed, followed by peel, and cortex. Soluble protein levels in the seed were 7- and 12-fold higher than in the peel and cortex, respectively. Changes in the activities of these enzymes were related to growth and development of apple flower and fruit.