[Chromosomal variability of 2 species of Nicotiana in fluid culture].

The chromosomal number in relation with the age of suspension culture of nicotiana glauca (NG) and the non tumorous N. glauca x N. langsdorffii hybrid has been studied. In both species, an higher variability of chromosome number is present in younger culture. Aged cultures show a stabilization, for NG, around the hexaploid number (3n = 72) and for NNT, which is an amphidiploid specie, on the tetraploid level (4n = 84). Both species show, with the age of culture, a decrease in plant regeneration capacity, which is not due to chromosomal variability, since young cultures are much more variable than older one.