Isatis indigotica seedlings derived from laser stimulated seeds showed improved resistance to elevated UV-B

Sterilized seeds of Isatis indigotica (Brassicacae) were divided into four groups based on irradiation pretreatments. These control groups (C) were non irradiated, He-Ne laser treated seeds (L), UV-B treated seeds (B) and He-Ne laser followed by UV-B radiation treated seeds (LB). Laser radiation was provided by He-Ne laser, UV-B radiation was provided by filtered Qin brand 30 W fluorescent sun lamps. Malondialdehyde (MDA), proline, UV-B absorbing compounds and ascorbic acid (AsA) concentrations, as well as, the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were measured in the cotyledons of seedlings from all the four irradiation treatments. The result indicate that UV-B radiation enhanced the concentration of MDA while decreasing the activities of SOD, CAT, POD and the concentration of AsA in the seedlings compared with the controls. The concentration of MDA decreased, while the activities of SOD, CAT, POD and the concentration of AsA increased in seedling treated with He-Ne laser and UV-B compared to UV-B alone. The concentration of proline and UV absorbing compounds increased progressively with treatments i.e. UV-B irradiation, He-Ne laser irradiation, and He-Ne laser irradiation followed by UV-B irradiation compared to the controls. The present data suggest that Isatis indigotica seedlings derived from laser stimulated seeds showed improved resistance to elevated UV-B.