Thermal neutron induced changes in Saintpaulia

Saintpaulia ionantha “Ulery” Wend. cuttings were irradiated with thermal neutrons (250, 1000 and 5000 rad) to determine radiation effects on lethality, root formation, morphology and peroxidase isozymes. Lethality was high at the high doses. Irradiated cuttings showed increases in the time required for roots to form. Although no morphologically distinct mutants were recovered, separation of peroxidase proteins showed that radiation permanently altered peroxidase isozyme patterns. Radiation-induced mutations increased the number of isozymes which were catalytically active but different in their electrophoretic mobility. Radiation also destroyed the catalytic activity or suppressed synthesis of native isozymes. Thus, the isolation of peroxidase isozymes served as an effective genetic marker for radiation-induced mutants.