Coumaroyl alcohol dehydrase (CAD), peroxidase (POD) and polyphenol oxidase (PPO) are involved in lignin biosynthesis. Their gene expressions in ‘Golden Delicious’ apple peels were increaseddramatically after 30 DAFB. However, the expressions of the segenes were down-regulated by CA application, and the grand means of the CA treatment were 83%, 95% and 76% of that of the control, respectively (Fig. 9).