Effects of pre-treatment and post-treatment of allantoin (AT) on superoxide dismutase (SOD) activity (A), catalase (CAT) activity (B), ascorbate peroxidase (APX) activity (C), soluble peroxidases (SPO) activity (D), ionic peroxidases (IPO) activity (E), glutathione peroxidase (GPX) activity (F), phenylalanine ammonia-lyase (PAL) contents (G), and polyphenol oxidase (PPO) activity (PPO) (H) in tomato plants grown 15 days in presence and absence of UVC stress. Each boxplot shows values of five independent replicates (n = 5). Boxplots specified with the same letter(s) are statistically non-significant at p < 0.05 based on Tukey’s test. Treatments are the same as Figure 1.