Mikhail Semenovich Tsvet

Born May 14, 1872, in Asti, Italy; died June 26, 1919, in Voronezh. Russian plant physiologist and biochemist.

Tsvet graduated from the University of Geneva in 1893. He received his doctorate there in 1896 for his work “The Study of Cell Physiology,” which was published in 1896. After coming to Russia, he studied chlorophyll in the phytophysiological laboratory of the St. Petersburg Academy of Sciences on the suggestion of A. S. Famintsyn. Beginning in 1897 he taught botany in courses organized by P. F. Lesgaft at a St. Petersburg biological laboratory. In 1901 he defended his masters thesis, “The Physicochemical Structure of the Chlorophyll Grain.” In 1902, Tsvet became an assistant in the department of plant physiology and anatomy at the University of Warsaw, and in 1908 he was made an instructor in botany at the Warsaw Polytechnic Institute. In 1910 he defended his doctoral dissertation, “The Chromophylls in the Plant and Animal Kingdoms,” which was awarded an academic prize in 1911. From 1917 he was a professor at Iur’ev University (now the University of Tartu), and from 1918, at the University of Voronezh.

Tsvet’s main works were on plastids and plant pigments and on the development of methods for studying them. Of particular significance is the method he devised for separating substances using selective sorption of the components of a mixture by various adsorbents; the method was first set forth in his paper “On a New Category of Adsorptive Phenomena and Their Application to Biochemical Analysis” (1903) and was subsequently developed in other works (1906–10). The method enabled Tsvet to prove the heterogeneity of the green and yellow pigments of plant leaves and to obtain chlorophyllins α, β, and γ (now called chlorophylls a, b, and c) and a number of isomers of xanthophyll.

Tsvet’s discovery was widely used and recognized beginning in the early 1930’s in the analysis and identification of various pigments, vitamins, enzymes, hormones, and other organic and in organic compounds, and it was the basis for a number of new directions in chromatography. His conclusions about the nature of chloroplasts, the state of chlorophyll in plants, and the mechanism of photosynthesis are of essential significance in plant physiology.