THE EFFECTS OF FAST-NEUTRON RADIATION FROM A NUCLEAR DETONATION ON CHROMOSOME ABERRATION IN DATURA

Abstract

Seeds of Datura stramonium, Line 1, were dried to a constant moisture content of 4.9%, sealed in aluminum vials, and exposed to fast-neutron radiation from a nuclear detonation. The gamma ray contamination was approx. 25%. Similar seed lots of Line 1 were exposed to gamma rays from Co60 and to X-rays at the Brookhaven National Laboratory. Buds were obtained from the first 50 plants of each treatment where possible, and the metaphase and anaphase stages of the first meitotic division in the anthers were scored for aberrations. All types of aberrations increased linearly with dose of fast neutrons (ranging from 246 to 2000 rep), and the fast neutrons were about 14 times as effective as gamma rays or X-rays in producing chromosomal aberrations. However, the number of breaks per affected plant and the kinds of aberrations tended to be the same for the three types of radiations. The high biological efficiency of the detonation neutrons seems to be due to the higher probability of producing an aberration in any cell than in the case of gamma rays or X-rays, and is apparently not the result of contaminating radiation or of the extreme intensity of the radiation.