Abstract
To investigate the effects of and responses to ionizing radiation on woody plants, poplar (Populus nigra var. italica) plantlets were acutely exposed to 10-300 Gy of gamma-ray irradiation for 20 h and then cultivated under normal condition for 10 weeks. The elongation of shoots was delayed at 10-50 Gy, however the dry weights of the plants after 10 weeks were nearly the same as those of control plants. The growth of the plants was partially reduced and inhibited at 100 Gy. The poplars exposed to 150-200 Gy of irradiation could not grow and most of them died after 4 to 10 weeks. All plantlets exposed to 300 Gy of irradiation died between 4 and 7 weeks. The expression of both Rad51 and DNA ligase IV genes was induced by irradiation. This suggests that the repair of damaged DNA progresses in the poplar.
