Abstract
SummarySpores of the Royal fern, Osmunda regalis, were irradiated at different times after water uptake and before their first mitosis. 3H-thymidine labelling showed that light-grown cells synthesized DNA between 10 and 22 hours after water uptake, and half of these reached mitosis between 24 and 30 hours. Dark-grown cells did not synthesize DNA nor divide until given light. Sensitivity to killing by x-rays determined by D0 values of survival curves increased by a factor of 4·5 throughout interphase in light-grown cells but levelled off after 6 hours in dark-grown cells. The suggested correlation between increasing sensitivity and DNA synthesis was thus in the direction opposite to that seen in many other cell types. We conclude that a basic connection between radiation sensitivity and DNA synthesis is contra-indicated. The sparing effect of splitting the radiation dose into two equal fractions was approximately equal throughout interphase and was similar in light- and dark-grown cells. We conclude that t...
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: International journal of radiation biology and related studies in physics, chemistry, and medicine
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
