| Abstract: | In order to understand the role of active oxygen species in mediating plant injuries induced by far-UV radiation, seedlings of Taxus cuspidata Sieb. et Zucc. were irradiated by far-UV rays in laboratory for 4 weeks. The production of organic free-radicals in detached needles, and the production of O-·2 and 1O2 in isolated chloroplasts were detected weekly by electron spin resonance (ESR) to evaluate their relative importance. The results show that the cumulative effect of far-UV irradiation, is best indicated by the production of organic free radicals in the needles, O-·2 production in chloroplasts is the next. The enhancement of 1O2 production in chloroplasts by the cumulative far-UV irradiation seems to be not so important as O-·2 in mediating injuries induced by far-UV radiation because of its high background value. |
