The possible contribution of electron microscopy to the understanding of the mechanism of non-disjunction in man.

Sprout inhibition of onion bulbs can be effectively accomplished by low doses of radiation 2,3]. However, wholesomeness data on irradiated onions, particularly with respect to their mutagenic activity, are still insufficient for evaluation 6]. Therefore we examined the mutagenic activity of irradiated onions in bacterial systems. Because onion bulbs contain a considerable amount of free amino acids, we used indicator strains carrying the marker for mutagenicity other than the amino acid requirement.In this paper we describe the results on irradiated onions. We used tests with solid and liquid media, assaying for the streptomycin (SM) dependence in a strain having a tetracycline (TC)-resistance factor, as well as DNA repair tests using two sets of indicator strains.