Effects of hydroxylamine and N-Methyl-N'-Nitro-N-nitrosoguanidine in Mimulus cardinalis (Scrophulariaceae): Survival curves and dominant mutants.

The lethal and mutagenic effects of hydroxylamine (HA) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) were investigated in the higher plant Mimulus cardinalis. MNNG was found to be more toxic than HA. The shapes of the survival curves obtained at different concentrations of HA and MNNG are interpreted on the basis of decreased biological activity of the solution to increased age of solution. Based on the appearance of chlorophyll-deficient mutants, MNNG is mutagenic in Mimulus. No albinos were detected in HA treated plants. A total of 67 putative mutants were isolated in the mutation spectra of HA and MNNG treated plants. The frequency of mutants induced by HA and MNNG are different. MNNG is mutagenic at 1/10 the concentration of HA in inducing putative mutations in M 1 plants.