Radiobiological investigations in cereals

After X-irradiation of dormant caryopses of the different radiosensitive winter wheat varieties 'Bayro' and 'Walthari' from five successive harvest-years, a negative correlation bewteen phosphorus content of caryopses and their radiosensitivity was observed. To interpret the results two possibilities were discussed: 1. The amount of phosphorus content in developing embryos influences the size of chromosomes in the nuclei of the embryos and therefore also their radiosensitivity. 2. The intensity of physiological activities during the premitotic phase of germination, which depends on the phosphorus content, influences the duration of radiation-induced 'mitotic delay' and therefore also the process of repair in this phase. (author)