Effects of Acute Radiation on Reproductive Success of the Polychaete Worm Neanthes Arenaceodentata.

摘要

Laboratory populations of the polychaete worm Neanthes arenaceodentata were exposed to acute doses of external gamma radiation to determine effects on reproduction. Groups of mated pairs received either no radiation (controls) or 0.5, 1.0, 2.0, 5.0, 10, or 50 Gy. The doses were delivered at the time when oocytes were visible in the females and at a rate of 5 Gy/min. The broods from the mated pairs were sacrificed before hatching occurred, and information was obtained on brood size, on the number of normal and abnormal embryos, and on the number of embryos that were living, dying, and dead. The mean numbers of embryos in the broods from the mated pairs exposed to radiation were not significantly different from the mean number from control mated pairs, except for the groups receiving 10 or 50 Gy. However, there was a significant reduction in the percentage of live embryos in the broods from mated pairs that received doses as low as 0. 5 Gy. Also, increased percentages of abnormal embryos were found for the mated pairs exposed to 2.0, 5.0, 10, or 50 Gy. From data on estimated hatch size and actual hatch size, we determined that groups receiving doses as low as 0.5 Gy were significantly different from controls. An important effect of acute irradiation on mated pairs of N. arenaceodentata was increased mortality of the embryos. Except for those mated pairs that received 10 or 50 Gy, there was no evidence for gamete loss or for reduced fertilization success; the number of embryos in the brood did not decrease with increased dose. The results on embryo abnormality and mortality indicate that lethal mutations were most likely induced in the germ cells and that these affected survival of the early life stages. 28 refs., 8 figs., 15 tabs. (ERA citation 14:020743)