Navashin, Sergei Gavrilovich

Born Dec 1 (13), 1857, in the village of Tsarevshchina, in present-day Baltai Raion, Saratov Oblast; died Nov. 10, 1930, in Detskoe Selo, the present-day city of Pushkin, Leningrad Oblast. Soviet botanist and cytologist. Academician of the Academy of Sciences of the USSR (1918; corresponding member, 1901); academician of the Academy of Sciences of the Ukrainian SSR (1924).

Navashin became an instructor at Moscow University after completing his studies there in 1881. He also taught at the Petrovskoe Agricultural Academy and at the University of St. Petersburg. He was a professor at the University of Kiev from 1894 to 1915 and at the University of Tbilisi from 1918 to 1923.

In 1923, Navashin was one of the founders of the K. A. Timiriazev Biological Institute in Moscow; he served as the institute’s director from the time of its founding until 1929. He discovered that the pollen tube in birches penetrates the embryo sac at the ovule’s base in the chalaza. As a result, he was able to establish the presence of chalazogamy in other monochla-mydeous plants. Navashin’s discovery of double fertilization in angiosperms is of major significance, since it explains the nature of their triploid endosperm, as well as the nature of xenias. He laid the basis for studying the morphology and the taxonomic importance of the chromosome. Navashin founded the Russian school of plant cytology and embryology.