Mykola Hryhorovych Kholodny (; 22 June 1882 – 4 May 1953) was an influential microbiologist who worked at the University of Kyiv,

Ukraine Ukraine is a country in Eastern Europe. It is the List of European countries by area, second-largest country in Europe after Russia, which Russia–Ukraine border, borders it to the east and northeast. Ukraine also borders Belarus to the nor ...

in the

USSR The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

during the 1930s. He is known for the Cholodny–Went model, which he developed independently with Frits Warmolt Went of the

California Institute of Technology The California Institute of Technology (branded as Caltech) is a private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small group of institutes ...

. Despite being associated with the same theory, the two men never actually met. Cholodny worked in the A.V. Fomin Botanical Garden, attached to the University of Kyiv. He was one of the pioneers of the concept that microbes adhere to surfaces, using the technique of first placing glass slides in earth for a measured time period, then using a microscope to examine the slides. The

Prokaryote A prokaryote (; less commonly spelled procaryote) is a unicellular organism, single-celled organism whose cell (biology), cell lacks a cell nucleus, nucleus and other membrane-bound organelles. The word ''prokaryote'' comes from the Ancient Gree ...

''Leptothrix cholodnii'' is named after him. In 1927 Cholodny proposed that the cells of the

coleoptile Coleoptile is the pointed protective sheath covering the emerging shoot in monocotyledons such as grasses in which few leaf primordia and shoot apex of monocot embryo remain enclosed. The coleoptile protects the first leaf as well as the growing ...

are first polarized under the influence of uneven exposure to light, so growth hormone can diffuse more rapidly towards the side in the shade than in any other direction. Went reached the same conclusion in 1928, and the two scientists' names have been attached to the controversial Cholodny–Went theory.

Bibliography

Selected works include: *1926 ''Die eisenbakterien : bieträge zu einer monographie'' by N Cholodny *1928 ''Über eine vermeintliche Anomalie im Wachstumsmodus der Wurzeln von Lupinus albus'' by N Cholodny *1932 ''Lichtwachstumsreaktion und Phototropismus 2'' by N Cholodny *1933 ''Zum Problem der Bildung und physiologischen Wirkung des Wuchshormons bei den Wurzeln'' by N Cholodny *1939 ''Spezielle Methoden''. In 1937 N. G. Cholodny and E. Ch. Sankewitsch published an article on ''Influence of weak electric currents upon the growth of the coleoptile'' in ''

Plant Physiology Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants. Plant physiologists study fundamental processes of plants, such as photosynthesis, respiration, plant nutrition, plant hormone functions, tr ...

''. The same year he published an article on ''Charles Darwin and the modern theory of tropisms'' in ''Science'' magazine.

References

1882 births 1953 deaths People from Tambov People from Tambovsky Uyezd Soviet botanists Members of the National Academy of Sciences of Ukraine Recipients of the Order of Lenin {{Biologist-stub