Studies on the Formation of Ascorbic Acid in Detached Apple Leaves

Abstract

D-glucuronolactone caused a significant increase in ascorbic acid content of detached apple leaves after 24 hours at 1700 ft. - c. After 48 hrs. no significant increase was found with any of the experimental substances indluding D-glucurono-lactone, L-gulonolactone, D-galacturonic acid, glucose, fructose, sorbose, sorbitol, fructose-1,6-diphosphate, sucrose, D-glucuronic acid, L-gulonolactone, 3-keto-1-gulonic acid, glucosecycloacetoacetic acid, pyruvate, L-threonic acid and oxalic acid. The high correlation coefficient between ascorbic acid content and leaf area indicated the close relationship between photosynthetic activity and ascorbic acid content in apple leaves. The light sensitivity of ascorbic acid synthesis was confirmed by C14O2 experiments but the results suggest that only certain steps in this synthesis are light sensitive.