Despite the importance of ascorbic acid, only recently has its biosynthetic pathway been elucidated. The pathway proposed by Wheeler et al. (1998) appears to be the main one for the synthesis of AsA in plants. This pathway was shown to be present in different plant sources but, until now, not in fruits. The pathways of biosynthesis and degradation of AsA have been studied with the help of tissue infiltration, sometimes with the use of radioactive labeling. Experiments involving the infiltration of D-[6-14C]-glucose and D-[6-14C]-glucosone in bean seedlings and D-[1-14C]-glucose in watercress, parsley and geranium leaves confirmed the conversion of these precursors into AsA (Loewus and Jang, 1957; Williams and Loewus, 1978; Helsper et al., 1982; Loewus et al., 1987).