INDUCED POLLEN LETHALS FROM SEEDS OF DATURA STRAMONIUM EXPOSED TO RADIATION FROM A NUCLEAR DETONATION

Abstract

Seeds of Datura stramonium, Line 1, which had been dried to a constant moisture content of 4.9% and sealed in aluminum vials, were exposed to fast-neutron radiation from a nuclear detonation, with shielding from blast, heat and much of the gamma radiation. Seeds from the same sample were treated with gamma rays from Co60 and with X-rays. On the resulting plants pollen was examined from a single flower from each of the two main forks. Three types of abnormal pollen were distinguised; the normal grain, the chromosomal type (small, shriveled, empty grain); and the gene type (subnormal to very small grain). 84%, of the control seeds germinated and all the seedlings matured. From the nuclear detonation a few seeds germinated for doses of 4000 and 7000 rep, but none of the plants matured. For doses of 246, 760, 1400 and 2000 rep the percent germination was 84, 82, 73 and 58, resp., and the percent plants maturing were 75, 74, 55 and 30, resp. For 10,000 r units of gamma rays 84% of the seeds germinated and 80% of the plants matured. For 10,000 and 20,000 r units of X-rays the percent germination was 71 in both cases and the percent plants maturing were 65 and 60, resp. Equivalent percentages of plants with pollen abnormalities were obtained from 10,000 r of gamma rays and of X-rays and from about 760 rep of fast neutrons. The same relationship among the three types of radiations was obtained for the frequencies of the different types of pollen lethals. In scoring induced pollen lethal sectors, the X-ray data were too limited for comparison, but for gamma rays the equivalence of detonation fast neutrons was around 800 rep. Plants with a single type of pollen aberration usually had the chromosomal kind. A higher frequency of plants with the single pollen aberration type resulted from 760 rep of fast neutrons than from a higher or lower dose estimate. The results of these studies indicate that fast neutrons from a nuclear detonation are 13 or 14 times as efficient as gamma rays or X-rays in producing pollen lethals in Datura.