title: Induction by gamma-radiation of DNA synthesis in radicle cells of germinating seeds of Pisum sativum l.
abstract: In radicle meristem cells of germinating seeds of the pea (Pisum sativum L) before the onset of replicative synthesis of DNA, irradiation with 2-3 krad of gamma-rays induced the incorporation of 3H-thymidine (3H-TdR). Maximum isotope incorporation was noted during the first 2 hours after irradiation. Higher doses of radiation suppressed 3H-TdR incorporation. It was not seen after gamma-irradiation of air-dried seeds, nor after fast-neutron irradiation. The replication inhibitors hydroxyurea and 5-aminouracil had no effect on the gamma-induced incorporation of 3H-TdR, Whereas caffeine and acriflavine inhibited it to some extent. It is suggested that the gamma-radiation-induced incorporation of 3H-TdR in meristem cells during the pre-replicative period may be connected with repair phenomena.
mesh_terms: D000167:Acriflavine / Q000494:pharmacology; D002110:Caffeine / Q000494:pharmacology; D003037:Cobalt Radioisotopes; D004260:DNA Repair; D004261:DNA Replication / Q000187:drug effects; D005720:Gamma Rays; D006918:Hydroxyurea / Q000494:pharmacology; D011831:Radiation Genetics; D012639:Seeds / Q000187:drug effects / Q000528:radiation effects*; D014498:Uracil / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D003037:Cobalt Radioisotopes; D000167:Acriflavine; D002110:Caffeine; D014498:Uracil; D006918:Hydroxyurea