DNA-binding fluorochromes are often used for vital staining of plant cell nuclei. However, it is not always sure whether the cells after staining still remain in living state. We chose several criteria to estimate the validity of real vital staining for sexual cell nuclei.These were: the cytoplasmic streaming in pollen tubes whose nuclei were stained, the simultaneous visualization of fluorochromatic reaction and nucleus staining in isolated generative cells, and the capability of isolated, prestained generative or sperm cells to fuse with other protoplasts. The results confirmed that 4’,6-diamidino-2-phenylindole (DAPI), Hoechst 33258 and mithramycin could be used as real vital stains, though their efficiency varied from case to case; among them DAPI showed best effect. The fluorescent vital staining technique offered a useful means foridentification and selection of heterokaryons in gametoplas manipulation studies. DNA-binding fluorochromes are often used for vital staining of plant cell nuclei. However, it is not always sure whether the cells after staining still remain in living state. We selected several criteria to estimate the validity of real vital staining for sexual cell nuclei. These were: the cytoplasmic streaming in pollen tubes whose nuclei were stained, the simultaneous visualization of fluorochromatic reaction and nucleus staining in isolated generative cells, and the capability of isolated, prestained generative or sperm cells to fuse with other protoplasts. The results confirmed that 4 ’, 6-diamidino-2-phenylindole (DAPI), Hoechst 33258 and mithramycin could be used as real vital stains, though their efficiency varied from case to case; among them DAPI showed best effect. foridentification and selection of heterokaryons in gametoplas manipulation studies.