On the base of these data one should be suggested that the genome of the chalazal polar nucleus of A. atroviolaceum undergoes complete or partially inactivation already at the megagametogenesis by transforming into facultative heterochromatin. During endosperm formation, genome of the chalazal polar nucleus should not play any essential role in the functioning of the endosperm nuclei and proceeds its elimination from the triploid endosperm genome originated by the triple fusion. Although, participation of the chalazal polar nucleus in the formation of the primary endosperm nucleus supports earlier hypothesis (Gvaladze, 1976) that a role of the chalazal polar nucleus of A. atroviolaceum in a triple fusion is restricted only to the initiation of earlier development of the endosperm in comparison with the embryo. Beginning with the 8-nucleate stage, in spite of the elimination of the chalazal polar nucleus genome from the endosperm nuclei, the development of diploid endosperm proceeds similar to the triploid endosperm of the other Allium species that do not possess pycnotic chalazal polar nucleus and are not characterized by DNA elimination from the endosperm nuclei.