INFLUENCES OF CROSSPOLLINATION AND SELFPOLLINATION ON PEROXIDASE-ACTIVITIES, ISOZYMES, AND HISTOLOGICAL LOCALIZATION DURING SHARPBLUE-BLUEBERRY FRUIT-DEVELOPMENT

Five-year old 'Sharpblue' southern highbush blueberry plants (Vacciniu m corymbosum L.) were self-and cross-pollinated ('O'Neal') to study pe roxidase (POD) activity, isozyme patterns, and histological localizati on during fruit development, Cross-pollination resulted in larger and earlier-ripening fruit. Activities of soluble and bound POD mere very high during fruit growth period I, with peaks at 10 and 20 days after self-and cross-pollination. Activity was much higher for cross-pollina ted fruit. During fruit growth period II, POD activities were low in b oth pollination treatments, During ripening, soluble POD increased, th en declined in both treatments, Bound POD activities increased during the color transition from blue to dark blue, with the inert ase greate r in self-pollinated fruit, Banding patterns of soluble and bound POD isozymes and their histological localization varied by pollination tre atment as well as fruit developmental stage. During fruit ripening, so luble POD activity appeared to be associated with color transition fro m light blue to blue, while bound POD activity appeared to be associat ed with color transition from blue to dark blue.