Red coloration of the skin discs started to develop 2 d after the onset of irradiation at a higher intensity of UV light. After 96 h of irradiation, anthocyanin con-tent in the skin increased along with the increasing intensity of UV irradiation (Fig. 5). The red coloration was clearly observed in the skin discs irradiated with UV light above 1.6 W•m-2 inten-sity (Fig. 6).