Abstract: In order to evaluate the radiation impact of nuclear facilities on terrestrial ecosystems, and to explore the effects and biological mechanisms of γ radiation on the offspring of Arabidopsis thaliana, the Col-0 Arabidopsis thaliana was selected and irradiated at different dose rates (0 mGy/h, 10 mGy/h, 20 mGy/h, 50 mGy/h, 100 mGy/h). The plant height, leaf length, leaf width, chlorophyll content, superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione reductase (GR), malondialdehyde (MDA), proline (PRO), and chlorophyll fluorescence indicators were measured. The results indicated that there were differences in the growth and development of Arabidopsis thaliana progeny after irradiation. The overall plant height showed a trend of increasing first and then decreasing. Plant leaves, MDA, POD, and effective photochemical quantum yield were the minimum points after 50 mGy/h irradiation. The SOD and CAT specific activity were the lowest at 20 mGy/h. GR and PRO showed that the irradiated Arabidopsis thaliana offspring plants were significantly lower than the control group. The content of chlorophyll a and chlorophyll b in 10 mGy/h and 50 mGy/h irradiation was significantly lower than other treatments. The non-photoquenching coefficient tendency indicates that low-dose rate irradiation did not cause irreversible damage to the photosynthetic response center PS Ⅱ in the offspring of Arabidopsis thaliana. Plants mainly respond to ionizing radiation by regulating the antioxidant enzyme system and osmolyte substances.

Key words: γ irradiation, Arabidopsis thaliana, first generation, physiological indicators, fluorescence parameters