Calculation of β-Ray Absorbed Dose Rate for131I Applied to the Inflorescence of Tradescantia

Effects of131I applied to the inflorescence on the induction of somatic mutations in Tradescantia stamen hairs were previously investigated, and the doubling dose (activity) was estimated to be 4 nCi (S. Tano and H. Yamaguchi, Radiat. Res. 80, 549-555 (1979)). In the present paper, the absorbed dose rate in stamen hairs of Tradescantia for β rays from the applied131I was calculated. The doubling dose for the131I (4 nCi) applied to the inflorescence was estimated to be higher than 0.3 rad (assuming uniform distribution of131I on the surface of the buds and assuming that the shape of the buds was a sphere) and lower than 1.0 rad (131I distributed uniformly in the buds).