2019 ASHS Annual Conference

Cutin is a polymeric protective coating of most aerial plant surfaces that is composed of primarily aliphatic mono, di, and tri-hydroxy fatty acids. Apple fruit cuticle is compiled of multiple layers of cutin overlaid and intercalated with a complex mixture of waxes and various freely soluble non-polar compounds. We extracted, hydrolyzed, and analyzed ‘Granny Smith’ apple cutin from stored fruit to determine if preharvest light exposure impacts postharvest cutin composition. Microscopic analysis revealed layered cutin periclinal and differential anticlinal deposition. Differences of cutin composition were also evident and continued to change with storage duration. Along with the freely extractable wax components, the dynamic composition and structure of this coating may govern gas, solute, and liquid transport influencing cell and fruit physiology to the point of altering fruit appearance or even ripening. Difference of cutin composition with sun exposure may provoke or be related to development of sunscald or other apple peel disorders.