Figure 4. Role of H₂S in the regulation of enzyme activities.

The activities of ascorbate peroxidase (APX) (A), catalase (CAT) (B), guaiacol peroxidase (POD) (C), lipoxygenase (LOX) (D), phenylalanine ammonia lyase (PAL) (E) and polyphenol oxidase (PPO) (F) were determined in pears. Pear slices were fumigated with 2.0 mM H₂S donor NaHS aqueous solution (H₂S) or with water as the control groups (CK) for 0−6 d. Data are presented as means ± SD (n = 3). FW: fresh weight.