Effects of storage conditions on survival and free radical populations in dried irradiated spores ofosmunda regalis
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Spores of the fernOsmunda regalis were irradiated and stored for 8 weeks in N2, NO, H2S and O2. They were examined at increasing times after irradiation using both e.s.r. and survival techniques. A synergistic, damaging effect of O2 and radiation was observed on storage. In contrast to the positive correlation of free radical changes with post-irradiation oxygen damage in short term experiments, damage observed on prolonged storage in O2 cannot be correlated with the observed radical changes. It is concluded that the mechanisms by which O2 acts shortly after irradiation and on storage are different. The slow decay of radiation-produced radicals in spores irradiated and stored in N2 was found to have no influence on the extent of radiobiological damage, which was unchanged with time. However, the e.s.r. results indicate a slow thermal annealment of radicals which were thought to be thermally stable and which have been correlated with precursors of post-irradiation oxygen damage. The anoxic component of radiobiological damage in spores irradiated in NO or H2S appeared to be unaffected by the extensive decay of radiation-produced radicals occurring on storage.
KeywordsOxygen Free Radical Radical Population Thermal Annealment Storage Condition
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