[en] Vicia faba roots were used in this study. Doses of 25 to 90 cGy of 600 MeV neutrons were given at the minimal depth in water as single doses or divided into two or three equal daily fractions. The dose rate was about 20 cGy/h. Doses of 68 to 254 cGy were given to the roots at a depth of 20 g/cm². The dose rate was 56 cGy/h. Between 25 and 30 bean roots were irradiated per group. Results were inconclusive, though there was some evidence to suggest that sensitization may have taken place with dose fractionation. (U.K.)