The reversion phenomenon in irradiated fern prothalli: Effects of acute or chronic anoxia and LET
| Autor: | K. H. von Wangenheim, F G Cowie, Jolyon H Hendry |
|---|---|
| Rok vydání: | 1985 |
| Předmět: |
Neutrons
Time Factors Radiation biology Cell Survival X-Rays Biophysics Reversion chemistry.chemical_element Dose-Response Relationship Radiation Plants biology.organism_classification Oxygen Cell biology Energy Transfer chemistry Botany Mitotic Index Fern Irradiation Mitosis General Environmental Science |
| Zdroj: | Radiation and Environmental Biophysics. 24:45-56 |
| ISSN: | 1432-2099 0301-634X |
| Popis: | In several systems a paradoxical reduction of radiation damage with increasing dose, termed reversion, has been observed. In the fern Osmunda regalis the percentage of cells which does not die but stays alive, although reproductively sterile, increases with dose. The assumed mechanism of this effect is a continuation of cytoplasmic growth during radiation-induced mitotic delay which induces terminal differentiation (early differentiation) thus preventing mitosis and the expression of chromosomal injury. Suppression of cytoplasmic growth after irradiation should abrogate reversion. This was tested using anoxia. Reversion was suppressed by storage of the sporelings in nitrogen for 8 h or more after X-rays, but was not suppressed by storage in 0.27 microM oxygen nor by a 60-min exposure to air after irradiation and before storage in nitrogen. Anoxia before irradiation in air had no effect. Anoxia only during irradiation showed an OER of about 2 for the reversion peak. The partial abrogation of reversion is consistent with the assumed mechanism. Marked reversion also was observed after 14.7 MeV neutrons. |
| Databáze: | OpenAIRE |
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