GENERIC DIFFERENCES IN ANTIOXIDANT CONCENTRATION IN THE FRUIT TISSUES OF FOUR MAJOR CULTIVARS OF APPLES
Apples have been cultivated for over two millennia and over 10,000 named cultivars exist. Antioxidants protect against oxidative stress and provide resistance against superficial scald in apple (Malus domestica Borkh). In the present study four commercially important apple cultivars (Red Delicious, Gala, Fuji and Granny Smith) and source leaves of Gala apple tree were studied. Ascorbate concentration, SOD activity, and protein concentration was determined for Gala leaves and all the four apple (fruit peel and fleshy cortex tissue) cultivars. Gala leaves had the highest ascorbate concentration and SOD activity. Granny Smith fruit peel tissue had the highest and Red Delicious fruit peel tissue had the lowest ascorbate concentration. Granny Smith fruit peel tissue had the highest SOD activity. These results demonstrate that ascorbate concentration and SOD activity in apple tissue may depend on their respective breeding parents, scald susceptibility and the amount of ethylene they produce.