title: The mutagenic effect of gamma rays on leaf protoplasts of haploid and dihaploid Nicotiana plumbaginifolia, estimated by valine resistance mutation frequencies.
abstract: Leaf protoplasts isolated from haploid and dihaploid Nicotiana plumbaginifolia plantlets were treated with different doses of gamma-rays and their survival was determined by scoring for plating efficiency at each irradiation dose. A fixed number of surviving protoplast-derived colonies was then plated in the presence of inhibitory concentrations of L-valine and incubated until growing resistant calli could be scored and mutation rates calculated. Though haploid protoplasts were found to be a little more sensitive than dihaploids to the lethal effect of radiation, the two dose-response curves of gamma-rays that induced mutagenesis were very similar. The irradiation dose capable of causing a ten-fold increase of spontaneous mutation frequencies was about 500 rads with both haploid and dihaploid protoplasts.
authors.affiliation: Biology Group, Directorate General XII, J.R.C. of European Communities, I-21020, Ispra, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Nielsen
authors.forename: E
authors.initials: E
authors.lastname: Selva
authors.forename: C
authors.initials: C
authors.lastname: Sghirinzetti
authors.forename: M
authors.initials: M
authors.lastname: Devreux