Cold, Nikolay Grigoryevich

Born in the family of a teacher in the Tambov gymnasium

In 1886, the Cold family moved to Voronezh . In 1892 he entered the Voronezh gymnasium, but studied there for only one year. In 1893, his father was transferred to Novocherkassk to the post of director of the gymnasium. In this gymnasium, he continued his further studies. Already in the gymnasium years, Nicholas showed an interest in natural science and he devoted all his free time to reading natural science literature and observations in nature.

After graduating from high school in 1900 he entered the natural department of the Faculty of Physics and Mathematics of Kiev University . In the 3rd year, he chose plant physiology as his specialty, but at the same time he was interested in studying the history of philosophy. Upon graduation in 1907, he was left as an assistant in the Department of Plant Physiology. In the summer of 1907, with the aim of studying nature, he traveled around the Crimea , and in 1908 and 1909 went abroad, visited Berlin , Paris , Zurich , Strasbourg , Munich , Vienna , Savoy and Tyrol , got acquainted with scientific institutions and museums, made excursions to the Alps .

In the years 1910-1912. passed master's exams, the program of which then included all botanical disciplines. In the summer of 1911, he, along with students - members of the circle of nature testers - traveled to the Urals .

In 1912 he began to give a course in microbiology at Kiev University and conduct practical classes, and in 1916 - a course in plant physiology. In January 1918, he was approved as an assistant professor at the university.

In 1919 he defended a master's thesis at the University of Kiev on the topic “On the Effect of Metal Ions on Irritation Processes in Plants”. In the same year he was awarded the academic title of professor at the Kiev Higher Women's Courses , where he taught botany since 1914.

In 1919, N. G. Kholodny began working at the Goristoye Dnieper Biological Station , where over the years he has completed over 40 scientific studies on a variety of topics. At the same time, he headed the Department of Plant Physiology at Kiev University and taught physiology, plant anatomy, and microbiology there.

In 1920, he was accepted as a research fellow at the Ukrainian Academy of Sciences . In 1926, he was awarded the degree of Doctor of Botany without defending a dissertation for a monograph on iron bacteria . The monograph was highly appreciated by prominent Russian microbiologists - S. N. Vinogradsky , V. L. Omelyansky , D. K. Zabolotny .

In 1925 he was elected a corresponding member of the Academy of Sciences of Ukraine, and from 29.06.1929 he was a full member in the specialty of agricultural sciences.

In 1933 he was appointed editor of the journal of the Institute of Botany of the Academy of Sciences of Ukraine.

During the Great Patriotic War, N. G. Kholodny worked in Krasnodar at the All-Union Scientific Research Institute of Tobacco Production , then in Sochi in the arboretum and experimental station of the NKZ of the USSR , and since 1942 in Yerevan and in the Kirovokan department of the Yerevan Botanical Garden , where he continued to conduct experimental work. In 1945, he returned to Kiev, but during the years of occupation in the city all the manuscripts of the scientist, correspondence and a large collection of drugs were lost.

In the post-war years, every winter, due to poor health, Nikolai Grigoryevich left for Sochi, and in the summer he conducted large-scale research work at Goristy — he set up experiments and made observations in nature. He continued to tour a lot.

In 1953, his heart disease worsened, and on May 4, 1953, he died in Kiev.

Nikolai Grigorievich Kholodny had many followers and students, he left more than 200 scientific works. Most of the works relate to plant physiology ; in addition, he owns interesting studies in the field of plant ecology , microbiology, and soil science .

Kholodny N.G. is the founder of the phytohormonal theory of tropisms , which explains the growth movements of plants. He found that increased doses of auxin inhibit the growth of the root or completely stop it, and a thickening appears in the growth zone. This allowed us to identify ways to control weeds with the help of certain synthetic substances. Almost simultaneously and independently of Kholodny, similar ideas were expressed and substantiated by experimental data by the Dutch phytophysiologist F. Vent (1928). It is known in the world as the Cold-Vent hypothesis.

Another important contribution of Kholodny to science was the development of the problem of volatile organic compounds of the atmosphere and the elucidation of their biological role.

Cold N. G. conducted experiments on artificial stimulation of plant development, which is now widely used in agricultural practice around the world. Of great value are his studies on the morphology and physiology of iron bacteria .

He was also involved in environmental research, soil science research. He proposed new methods for accounting for the amount of soil bacteria . He developed general biological issues - the emergence of life on Earth, evolutionary theory , and the history of science .

Theory of Geotropism

Kholodny N.G. began his journey in science by studying plant tropisms , and this largely determined the main direction of his research. The first generalization of many years of experiments was the physicochemical theory of geotropism , which he regarded as a useful working hypothesis . Its essence is this. The force of attraction , acting on the plant organ, causes in the protoplasm of its cells a special character of the distribution of large colloidal particles of protoplasm in them, which carry an electric charge . As a result of this, an electromotive force arises in the cell, it is directed parallel to the direction of gravity and causes the movement of cations in the cell. As a result of this, changes occur in the ratios of concentrations of monovalent and divalent ions in the protoplasm of the upper and lower parts of the cell, which causes an increase or decrease in the permeability of protoplasm. Different permeability is associated with different influx of plastic substances into separate sections of the protoplasm, and the cell membrane growth activity on opposite sides of the cell depends on this. The sum of such cellular effects is manifested in the orientation of the geotropic bending of the plant organ.

In the years 1918-1923. different authors have proposed other ionic or electrical hypotheses of geotropism. The hypothesis of N. G. Kholodny was the first in this regard, chronologically preceded by them. At the same time, its author saw the insufficient experimental validity of its provisions, realized the need for further work on this problem.

The doctrine of phytohormones

A further development of his research was the doctrine of phytohormones - it was then a new, almost unexplored area of ​​phenomena. N. G. Kholodny conducted a significant part of phytohormonal studies at the Staroselskaya Biological Station. Research 1924-1926 gave MG G. Kholodny experimental foundations for formulating a new, already hormonal , hypothesis of geotropism. It was suggested that, when the root or stem is horizontal, the growth hormone is distributed unevenly in them, in a greater amount it is concentrated in the cells of the lower side of the organ. In the stem and other negative geotropic organs, this causes an increase in the growth of the lower side and, as a result, a negative geotropic bend. An increase in the hormone content in the cells of the lower side of the root causes growth inhibition here, as a result of which the root bends downward (positive geotropism). Developing his ideas, M.G. Kholodny extended them to the phenomena of phototropism (1927).

Hormonal Theory of Tropisms

At the same time, he also had to attempt to propose a general theory of tropisms, which was already based on ideas about the important role of growth hormone in these phenomena. Almost simultaneously and independently of N. G. Kholodny, similar ideas were expressed and substantiated by experimental data by the Dutch phytophysiologist F. Vent (1928). Cold - Hypothesis Venta quickly found recognition among most phytophysiologists, gradually turning into a hormonal theory of tropisms. On the whole, it did not cause serious objections; disputes arose mainly on the basis of different interpretations of some experimental data on which it was based. Its creators continued to work on strengthening its foundation with new experimental data, on elucidating the mechanism of movement of growth hormone under the influence of electrophysiological polarization of tissues.

About the role of hormones in tropism, N. G. Kholodny published about 40 works. In the mid-1930s, the hormonal theory of tropisms became generally accepted. There are three main facts that have been experimentally established by N. G. Kholodny, F. Vent, and other researchers:

• electrophysiological polarization of tissues of plant organs under the directed action of external factors ( gravity , light );
• uneven distribution in the tissues of growth hormone due to electric polarization;
• uneven response of growing tissues of various plant organs to the action of growth hormone solutions of the same concentration.

N. G. Kholodny considered the development of the hormonal theory of tropisms and the fact of the enormous role of phytohormones in plant growth the first and most significant result of his research on the physiology of hormonal phenomena in plants. The huge merit of N. G. Kholodny in the development of the study of plant hormones as a whole was recognized by all scientists. He is rightfully considered the founder and inspirer of the development of the doctrine of phytohormones. The monograph “Phytohormones” (1939) became a generalization of his many years of research on this problem.

The Role of Volatile Organic Atmospheric Compounds

The next important contribution to the science of N. G. Kholodny was the development of the problem of volatile organic compounds of the atmosphere and the elucidation of their biological role. According to it, he published 18 works. Studies by N. G. Kholodny have shown that volatile organic compounds that are released into the atmosphere by the Earth’s vegetation do not disperse without a trace. Their main mass is obviously absorbed by the soil and used by its microbial population . Thus, another link was discovered in a complex chain of phenomena of the cycle of substances in the biosphere , due to the vital activity of the organisms that inhabit it. N. G. Kholodny focused on the fact that the gas shell of the Earth , or rather its troposphere , represents that "nutrient medium" from which organisms take almost all the substances necessary for life. These ideas were appropriately correlated with the ideas of his long-standing correspondent, academician V.I. Vernadsky, on the bilateral nature of the relationship between the Earth’s atmosphere and its biosphere.

With his research, N.G. Kholodny significantly expanded his knowledge of the phytogenic and other organic components of the atmosphere. He proved that these substances can be absorbed by many soil microorganisms and, under certain conditions, serve as an additional source of carbon nutrition for them. He made a significant contribution to the development of methods for studying the microbial population of soils and reservoirs, and to the development of the environmental trend in microbiology . He owns the original idea of ​​the emergence of organic substances on Earth in an abiogenic way . He enriched many sections of modern biology with interesting ideas and experimental material. N. G. Kholodny and V. I. Vernadsky outlined a program for the study of air vitamins , about which Vernadsky wrote: “... such a study should be of great importance for medicine, meteorology, and especially biochemistry, because the diversity of gas minerals in the troposphere should be estimated in thousands of species” .

• Order of Lenin (01/10/1944)

In 1971, the Institute of Botany of the Academy of Sciences of the Ukrainian SSR was named after N. G. Kholodny. In 1972, the N. G. Kholodny Prize was established at the Academy of Sciences of the Ukrainian SSR, which is awarded for outstanding work in the field of botany and plant physiology.

• Cold N. G. Darwinist's thoughts on nature and man. - 1944.
• Kholodny N. G. The thoughts of a naturalist about nature and man. - 1947.
• Kholodny N. G. On the Problem of the Emergence and Development of Life on Earth . - 1945. Archived on January 29, 2005.

• Bazilevskaya N.A., Meyer K.I., Stankov S.S., Shcherbakova A.A. Outstanding domestic botanists. - M .: Uchpedgiz , 1957. - S. 407-417. - 441 p.
• Smaliy V.T. Mikola Grigorovich Kholodniy (Ukrainian) // Mikrobiologicheskiy zhurnal. - 1953. - T. 15 , no. 3 .
• Belokon I.P. N. G. Kholodny // Botanical Journal . - 1953. - Issue. 3 .

• Cold Nikolai Grigoryevich // Great Soviet Encyclopedia : [in 30 vol.] / Ch. ed. A.M. Prokhorov . - 3rd ed. - M .: Soviet Encyclopedia, 1969-1978.
• Kholodny, Nikolai Grigoryevich in the Big Biographical Encyclopedia (Retrieved December 25, 2009)
• Kholodny, Nikolay Grigoryevich in the Newest Philosophical Dictionary (Retrieved December 25, 2009)