[Studies on the significance of vegetative nuclei and their nucleoli in pollen grains and pollen tubes].

The communication deals with a study of the significance of vegetative nuclei of pollen grains. The study of vegetative nuclei was performed with pollen grains and pollen tubes of a tulip (Tulipa gesneriana, var. Bellona).The conclusions are summarized as follows: 1. The vegetative nucleus does not participate directly in the regulation of growth of the pollen tubes. 2. Stimulation of the growth of pollen tubes induced by means of boric acid is not accompanied by a simultaneous stimulation of spiralization of chromosomes in the generative nucleus or by its division. 3. The vegetative nucleus and its nucleolus take part in the division of the generative nucleus. 4. In the course of spiralization of the chromosomes of the generative nucleus, the nucleolus disappears from the vegetative nucleus. The vegetative nucleus, however, persists in spite of a decrease in DNA content. 5. The vegetative nucleus disappears after formation of spermatic nuclei.