RESUMO
The mitotic activity and ploidy of cells of three strains of cellus tissue by the addition of the culture medium of 0,01; 0,1 and 1 mg/l of phytohemagglutinin was studied. These strains derived from the leaves of haploid, diploid, and tetraploid plants of Lycopersicon, esculentum. The number of dividing cells under the influence of phytohemagglutinin increased by 1;5 and 4% for haploid, diploid and tetraploid strains respectively. The shift of the peak of the mitotic activity at early stages of subculture under the effect of phytohemagglutinin was noticed. Phytohemagglutinin did not change the frequencies of cells of different ploidy in all the strains analysed. A weak mutagenic activity of phytohemagglutinin in the concentrations used was observed. Cells with single bridges were more frequently observed among the aberrant cells.