title: Ionizing radiation promotes protozoan reproduction.
abstract: This experiment was performed to determine whether ionizing radiation is essential for maximum growth rate in a ciliated protozoan. When extraneous ionizing radiation was reduced to 0.15 mrad/day, the reproduction rate of Tetrahymena pyriformis was significantly less (P less than 0.01) than it was at near ambient levels, 0.5 or 1.8 mrad/day. Significantly higher growth rates (P less than 0.01) were obtained when chronic radiation was increased. The data suggest that ionizing radiation is essential for optimum reproduction rate in this organism.
mesh_terms: D001417:Background Radiation; D002588:Cesium Radioisotopes; D011197:Potassium Radioisotopes; D012098:Reproduction / Q000528:radiation effects; D013769:Tetrahymena pyriformis / Q000528:radiation effects*
chemical_list: D002588:Cesium Radioisotopes; D011197:Potassium Radioisotopes