Abstract
Inflorescences of Tradescantia reflexa (4x, 2n=24) KU 7 clone which is heterozygous for flower color (blue/pink, blue being dominant) were irradiated acutely with 37 to 141 rads of 14.1MeV fast neutrons and with 144 to 362rads of 137Cs gamma rays. The stamen hairs of the irradiated and control flowers were examined daily for 19 days after irradiation.
At the time when the maximum radiation effects were observed, 1) the average number of cells per hair, 2) percentage of stunted hairs, 3) postirradiation growth of hairs, 4) pink mutant events per hair, 5) percentage of pink mutant cells, and 6) colorless events per hair were calculated for each dose and the effects of fast neutrons and gamma rays were compared. The determined RBEs of 14.1MeV fast neutrons as compared with 137Cs gamma rays for the above six end points were 1) 3.95, 2) 3.50, 3) 3.41, 4) 5.05, 5) 4.82, and 6) 5.32, respectively. These RBE values are much lower than those usually obtained from higher plants (mostly dry seeds) and are closer to those from other organisms. This point is discussed with respect to water content and dose-rate effects.
