The use of sodium nucleate in the study of the mutagenic activity of acriflavine in Escherichia coli.

that the pollen grains had germinated and that the pollen tubes had penetrated the stylar tissue. Demerec's third suggestion remains as a possibility and a fourth may be added which is likewise untested. The failure of gal pollen to fertilize Gals plants may be independent of stylar interaction altogether, and may involve some abnormal reaction within the ovule, such as inability of the pollen tube to penetrate the embryo sac. None of these explanations, however, are applicable in the case of Gal-gal competition since, in the absence of Gal pollen, gal gametes function normally on Gal styles. A number of cases of cross-sterility in maize may be due to the action of Gais. This is especially true of the cross-sterility found among varieties of popcorn.2 Although the point of origin of the Gals allele is not known, the fact that both Ga1 and Demerec's cross sterility factor were found in popcorn supports this contention.