The Oxygen Requirement for Recovery in Split-dose Experiments with Oedogonium

Summary

Split-dose experiments with vegetative stationary-phase cells of Oedogonium cardiacum, tested for loss of clonogenic ability, showed that part of the x-ray damage was repaired in a 2-hour interval. The ability of the cells to repair was independent of the presence of oxygen during irradiation. When less than 0·01 µM/l. oxygen was present in the water surrounding the cells during the recovery interval, little or no recovery occurred. When 0·12 µM/l. oxygen was present, recovery was as complete as in air-saturated water. These results, and others quoted in the literature, support the hypothesis that recovery is a metabolic process which requires an energy source in the cell.