Ovules of plum cultivars (Sweet Common Prune, Herman, Gilbert, Sanctus Hubertus, Cacanska Rodna, Cacanska Najbolia) were pollinated with pollen of cv. Stanley on the White?a medium with addition of 15% sucrose. The nucelluses excised from the fertilized ovules were cultivated on Norstog medium with addition of 3,4% sucrose. The process of fertilization after pollination in the in vitro condition was proved on the basis of the paraffin cross?sections: the degeneration of synergid after entering the pollen tube, the fertilization of egg cell were confirmed. The microscopic observations showed the swelling of micropylar part of nucellus. The paraffin cross-sections showed a many-layer kalotka (peculiar morphological structure) and swelled cells of nucellus among which the embryo sac was observed. The presence of embryo without endosperm or the presence of endosperm without embryo in the embryo sac was noted.