Study of external low irradiation dose effects on induction of chromosome aberrations in Pisum sativum root tip meristem.
The effects of low doses of ionizing radiation have been a matter of important debate over the last few years. The point of discussion concerns the validity of the linear dose-response extrapolation for low doses, used by international organizations, to establish radio-protection norms. Here, we contributed to this discussion by investigating the induction of chromosome aberrations by low to moderate doses ranging from 0 to 10 Gy in root meristem cells of 6-day-old Pisum plantlets. After acute irradiation of plantlets by a (60)Co source, the percentage of root tip meristem cells displaying chromosome aberrations was estimated immediately after irradiation and after 20 h recovery time. The dose-effect curves show non-linear responses, especially in the low dose range (0- 1 Gy), which is of particular interest. After 20 h of recovery, a steep increase of aberrations was observed for cells exposed to 0.4 Gy, followed by a plateau for doses until 1 Gy. There was an irradiation effect on plant growth during the first and second generations, showing the persistence of cell division anomalies as a long term effect of acute irradiation. This result suggests the induction of a genomic instability. Our results, in agreement with some obtained in animals, show rather non-linear dose-effect responses, with notably higher biological effects of low doses than expected.
Zaka
R
R
UMR-CNRS 6553 Ecobio, Equipe Evolution des Populations et des Espèces, Campus de Beaulieu, Université de Rennes 1, F 35042 Rennes Cedex, France.
Chenal
C
C
Misset
M T
MT
D002869:Chromosome Aberrations; D002875:Chromosomes / Q000528:radiation effects*; D003037:Cobalt Radioisotopes / Q000494:pharmacology; D004307:Dose-Response Relationship, Radiation; D018532:Pisum sativum / Q000528:radiation effects*; D013997:Time Factors
D003037:Cobalt Radioisotopes