X-RAY TOLERANCE OF LIVING CELLS AS MEASURED BY CYTOPLASMIC STREAMING

Abstract

An investigation was undertaken to determine the immediate effects of X radiation on living, nondividing cells using the rate of cytoplasmic streaming as a measure of cell vitality. The observations were carried out on stamen hairs and pollen tubes of Tradescantia paludosa (diploid) and Tradescantia virginiana (tetraploid). No significant variation in the rate of streaming of cytoplasm in either stamen hairs or pollen tubes was noted with low doses of X rays. In both diploid and tetraploid stamen hairs, 700,000 r. was required to stop all streaming. In the pollen tubes of diploid and tetraploid plants, all streaming was stopped by 250,000 r. and 200,000 r. respectively, a difference that was statistically significant. Greater sensitivity, as shown by resulting cell death, was found with an increased initial dosage of continuous irradiation.