Abstract
(1) The radiosensitivity of soaked barley seeds was directly dependent on their stage of development in relation to the cell cycle. (2) At any given stage of development there was a pronounced oxygen effect, but no effect of irradiation temperature in the range 2° to 20°c. There was no evidence of any temperature-dependent recovery process. (3) Similar responses were obtained when radiobiological damage was measured in terms of induced mutation, sterility, or growth inhibition.