CHLOROPHYLL FLUORESCENCE AS AFFECTED BY SOME SUPERFICIAL DEFECTS IN STORED APPLES

Chlorophyll fluorescence, skin coloration and surface contour were mea sured for apple (Malus domestica Borkh.) fruit with and without common storage and handling surface defects. Defects included CO2 injury in 'Empire', bitter pit in 'Jonagold', superficial scald in 'Cortland', ' Law Rome', 'Gala' and 'Red Delicious' and bruising in 'Cortland'. Meas urements were made along a transect established on the fruit surface. The fluorescence parameters, minimal fluorescence (Fo), maximal fluore scence (Fm) and photochemical efficiency (Fv/Fm, where Fv = Fm - Fo) w ere relatively similar around the circumference of undamaged control f ruit. Skin colour was not found to influence chlorophyll fluorescence. With the exception of bruises, there were marked changes in fluoresce nce in the areas where surface disorders or damage had developed. CO2 injury and bitter pit reduced Fv/Fm, whereas superficial scald did not . However, scald symptoms were accompanied by a reduction in Fo and Fm . The reduction in Fo and Fm became more marked as scald symptoms inte nsified during post-storage holding at 22 degrees C. Chlorophyll fluor escence may have some potential for sorting fruit having superficial d efects.