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Author: Stephan Stanev


General conclusions

Till the Liberation of Bulgaria from the Turkish yoke (1878) there were only beginnings of botanical knowledge, contained in the works of some medieval and renaissance scientists-encyclopedists and educators.

The first botanical investigations in Bulgaria concern its flora and were carried out by foreign travelers, naturalists and botanists, who visited this country in the 19th century (P. B. de Man, J. Sibthorp, E. Clarke, E. Frivaldszky, A. Grisebach, V. Janka, J, Pancic, J. Velenovsky, F. Bubak, etc.). By the last century appeared the first botanical publications written by Bulgarians. These were doctoral dissertations of bulgarian students studying abroad, in the field of morphology, anatomy, embryology and physiology (S. Georgiev, S. Petkov, P. Kozarov, T. Nicolov) and floristic and phytogeographical papers of teachers-naturalists working in Bulgaria (A. Yavashov, S. Georgiev, V. Kovatchev, A. Toshev, L. Urumov, B. Davidov etc.)

In the period till 1944 several botanical center in Bulgaria were set up: 1) Botanical Institute in the Faculty of Physics and Mathematics at the University of Sofia; 2) Departments of Agricultural Botany in the Faculty of Agronomy and Forestry at the University in Sofia; 3) Botanical Department at the Royal National History Museum; 4) Botanical Department at the Royal Agricultural Research Institute in Sofia; and, 5) Bulgarian Botanical Society.

The first peculiar feature of the botanical science during this period is the small number of botanists working in the centers mentioned above.

The second one was the prevailing investigations on the flora and vegetation above the rest of the botanical research altogether. As a matter of fact this is an objective process characteristic for the first steps of the botanical investigations for each country. Particularly for Bulgaria of great significance in this respect is its rich various flora that strongly attracts the interest of botanists, the poor equipment for experimental and microscopic botany and some subjective circumstances. Nevertheless the number of the morphological, anatomical, embryological, cytological, physiological and biochemical publications in Bulgaria in this period is not so small and respective investigations have not been so neglected, as it has been believed till now. The truth is that only few Bulgarian researches have devoted a longer term or their whole lives to investigations of some important botanical subject (P. Kozarov, T. Nikolov, N. Arnaudov, A. Zlatarov, M. Popov, M. Christov, G. Gentchev, D. Kostov, M. A. Christov, B. Stephanov, etc.)

The basic trends of research in the botanical fields of study under discussion are the following:

In the field of morphology and anatomy: the application of anatomical and morphological methods for the solution of taxonomical, phylogenetical, ontogenetical and applied-theoretical problems. The object of investigation are mosses, trees, grasses and some other plant groups (N. Arnaudov, N. Nikolov, S. Georgiev, B. Stephanov, etc.)

In the field of embryology and cytology: chromosome number investigations, meiosis, apomixis reproduction of cultural (Nicotiana, Triticum, Secale) and wild-growing (Hieracium, Potentilla, Dianthus, Poa) plants (M. Christov, G. Gentchev, D. Kostov, A. Popov, G. Papazova, M. A. Christov, etc.)

In the field of physiology and biochemistry: chemical composition, water relations, mineral nutrition, plant growth, development and resistance of cultural plants (P. Kozarov, A. Zlatarov, M. Popov, I. Popov, etc.)

The following most important achievements of the Bulgarian scientists could be pointer out:

N. Stojanov demonstrates that the tubers of the orchids resemble modified adventitious roots.

N. Arnaudov establishes that cleistocarpy in mosses is not a primary phenomenon but a result of regressive development; for the first time he describer in details the morphology and biology of the carnivorous Oomycetes.

P. Kozarov contributes with his experiments to confirm the assumption that water intake is not a simple osmotic phenomenon but a complex physiological process, which is influenced by the life condition of the cell.

T. Nikolov corrects the knowledge of the embryologists about the presence of archesporous tissue in the nucellus of Juglandaceae and the number of sinergids in the embryo sac.

M. Christov discovers the important relation between the chromosome numbers and the hybrid possibilities of the plants; he presents proofs and gives theoretical explanation of the assumption that apomixis is genetically determined and not a result of hybridization.

D. Kostov describes for the first time a case of androgenesis; he is the author of the world-wide known monograph "Cytogenetics of genus Nicotiana. Sofia, 1943", totaling 1072 pages.

G. Gentchev (together with A. Gustafsson) explains the mechanism of endopolyploidy in the somatic cells of some plants; he proves that pseudogamy in genus Potentilla is expressed in the independent development of the endosperm after the fertilization of the secondary nucleus.

M. Popov is one of the most prominent research workers in the world on the problems of cell stimulation until about the end of the 1920s thus favouring the further investigation of this problem.

A. Zlatarov is among the first biochemists who comes upon the idea for the participation of several di- and tricarbonic acids in the metabolism.

M. A. Christov establishes endospermal polyembryony for the first time in genus Poa.

B. Stephanov is the author of one of the most original ideas and explanations on the phylogeny, evolution and speciation of trees, taking into consideration in many cases the data from their morphology, anatomy and physiology.

In the last two decades of the examined period a Bulgarian school in morphology, anatomy and physiology of the plants was formed by Prof. N. Arnaudov, as well as, such one in embryology and cytology by Prof. M. Christov and Prof. G. Gentchev, which in the 1930s and 1940s together with the Swedish and German schools were one of the leading in Europe, particularly in the study of apomixis.



Important publications in English

Christoff, M. (1928) Cytological studies in the genus Nicotiana. Genetics, 13, 233-277.

Christoff, M. (1939) Polyploidy and apomictic development in the genus Potentilla.  Proc. Seventh. Intern. Gen. Congr.


Gentscheff, G., A. Gustafsson. (1939a) The double chromosome reproduction in Spinacia and its causes. I. Normal behavior. Hereditas, 25, 349-358.

Gentscheff, G., A. Gustafsson. (1939b) The double chromosome reproduction in Spinacia and its causes. II. An X-ray experiment. Hereditas, 25, 371-386.

Gentscheff, G., A. Gustafsson. (1940a) Partenogenesis and pseudogamy in Potentilla. Botaniska Notiser, 1940, 109-132.

Gentscheff, G., A. Gustafsson. (1940b) The balance system of meiosis in Hieracium. Hereditas, 26, 209-249.


Kostoff, D. (1927) Tube growth in Lytrum salicaria. Proc. Nat. Acad. Sci., 13, 253-255.

Kostoff, D. (1929) An androgenic Nicotiana haploid. Zeitschr. Zellforschg., 9, 640-642.

Kostoff, D. (1930a) Chromosomal aberants and gene mutation in Nicotiana obtained by grafting. Journ. Genet., 22, 399-418.

Kostoff, D. (1930b) Ontogeny, genetics and cytology of Nicotiana hybrids. Genetica, 12, 33-139.

Kostoff, D. (1930c) Protoplasmic viscosity in plants. I. Protoplasmic viscosity of dividing cells in floral buds of tobacco. Protoplasma, 11, 177-183.

Kostoff, D. (1930d) Protoplasmic viscosity in plants. II. Cytoplasmic viscosity in callus tissue. Protoplasma, 11, 184-189.

Kostoff, D. (1930e) Protoplasmic viscosity in plants. IV. Cytoplasmic viscosity in tumors of Nicotiana hybrids. Protoplasma, 11, 193-195.

Kostoff, D. (1930f) Tumors and other malformation on certain Nicotiana hybrids. Zentrbl. Bakt., 81, 244-260.

Kostoff, D. (1931) Variants and aberants of Nicotiana tabacum obtained experimentally. Biol. General, 7, 271-282.

Kostoff, D. (1932) Pollen abortion in species hybrids. Cytologia, 3, 337-339.

Kostoff, D. (1933a) A contribution to the sterility and irregularities in the meiotic processes caused by virus diseases. Genetica, 15, 103-114.

Kostoff, D. (1933b) Cytogenetic studies of the fertile hybrid Nicotiana tabacum X (N. sylvestris x N. rusbyi) x N. teiolex. Tr. Prikl. Bot. Gen. Sel., S II, 5, 167-205.

Kostoff, D. (1934a) A contribution to the meiosis of Helianthus tuberosus L. Zeitschr. Zuchtg. A: Pflanzenzuchtung., 19, 429-438.

Kostoff, D. (1934b) A haploid plant of Nicotiana sylvestris. Nature, 133, 949-950.

Kostoff, D. (1934c) Studies on the pollen-tubes. II. The dependence between the potency of the pollen-tube growth in foreign styles and the thickness of the pollen-tube and chromosome number. Current Science, 2, 464-466.

Kostoff, D. (1935) Chromosome alteration by centrifuging (preliminary report). Zeitschr. Ind. Abst., 69, 301-302.

Kostoff, D. (1937a) Chromosome alteration by centrifuging. Science, 86, p. 101.

Kostoff, D. (1937b) Chromosome behaviour in Triticum hybrids and allied genera. II. Tr. timopheevii (n = 14) x Secale cereale (n = 7) Zeitschr. Zuchtg. A: Pflanzenzuchtung., 21, 378-379.

Kostoff, D. (1937c) Chromosome behaviour in Triticum hybrids and allied genera. III. Triticum-Haynaldia hybrids. Zeitschr. Zuchtg. A: Pflanzenzuchtung., 21, 380-382.

Kostoff, D. (1937d) Cytological studies on certain progenies of the hybrid Triticum timopheevii x Triticum persicum. Cytologia (Fuje jubilee vol.), 262-277.

Kostoff, D. (1938а) A contribution to the chromosome structure and behaviour. Cellule, 47, 219-225.

Kostoff, D. (1938b) Heterochromatin at the distal ends of the chromosomes in Triticum monococcum. Nature, 141, 690-691.

Kostoff, D. (1938c) Heterochromatin, somatic "crossing-over" and the interchange hypothesis between non-homologous chromosomes. Proc. Ind. Acad. Sci., 8, 11-44.

Kostoff, D. (1938d) Irregular mitosis and meiosis induced by ace-naphtene. Nature, 141, 1144-1145.

Kostoff, D. (1938e) The effect of centrifuging upon the germinated seeds from various plants. Cytologia, 8, 410-412.

Kostoff, D. (1938f) The size and number of the chloroplasts and the chlorophyll content in euploid forms experimentally produced. Current Science, 7, 270-272.

Kostoff, D. (1939a) Abnormal mitosis in tobacco plants forming hereditary tumors. Nature, 144, p. 599.

Kostoff, D. (1939b) A contribution to the chromosome structure. Intern. Zellforscherkongress Zurich, 1938, p. 11.

Kostoff, D. (1939c) A contribution to the chromosome structure and behaviour in Triticum monococcum. Ibid., p. 11.

Kostoff, D. (1939d) Effect of the fungicide "Granosan" on atypical growth and chromosome doubling in plants. Nature, 144, p. 334.

Kostoff, D. (1939e) Evolutionary significance of chromosome length and chromosome number in plants. Biodinamica, 51, 1-14.

Kostoff, D. (1939f) Evolutionary significance of chromosome size and chromosome number in plants. Current Science, 8, 306-310.

Kostoff, D. (1939g) Induction of somatic chromosome chimeras by ace-naphtene and colchicine. Intern. Zellforscherkongress, Zurich, 1938, p. 11.

Kostoff, D. (1940a) Atypical growth, abnormal mitosis and polyploidy induced by ethylmercury-chloride. Phytopath. Zeitschr., 13, 91-96.

Kostoff, D. (1940b) Fertility and chromosome length. Correlations between chromosome length and viability of gametes in autopolyploid plants. Journ. Genet., 39, 469-484.

Kostoff, D. (1941) The problem of Haploidy (The cytogenetic studies on Nicotiаna haploids and their bearings to some other cytogenetic problems). Bibliogr. Genet., 13, 1-148.

Kostoff, D., N. Arutunova. (1937) Studies on polyploid plants. XV. Triticum-Haynaldia hybrids with special reference to the amphidiploids Triticum dicoccum x Haynaldia villosa. Current Science, 5, 414-415.

Kostoff, D., J. Kendall. (1929a) Irregular meiosis in Licium halimifolium produced by gall mites (Eryophies). Journ. Genet., 21, 113-115.

Kostoff, D., J. Kendall. (1929b) Studies on the structure and developments of certain cynipid galls. Biol. Bull., 56, 402-459.

Kostoff, D., J. Kendall. (1930a) Cytology of nematode galls on Nicotiana roots. Zentralbl. Bakt., 81, 86-91.

Kostoff, D., J. Kendall. (1930b) Irregular meiosis in Datura ferox caused by Tetranchus telarius. Genetica, 12, 140-144.

Kostoff, D., J. Kendall. (1930с) Protoplasmic viscosity. III. Cytoplasmic viscosity in cynipid galls. Protoplasma, 11, 190-192.

Kostoff, D., J. Kendall. (1931a) Studies on certain Petuniu aberantis. Journ. Genet., 23, 165-178.

Kostoff, D., J. Kendall. (1931b) Variants and aberants of Nicotiana tabacum obtained experimentally. Biol. General., 7, 271-282.

Kostoff, D., J. Kendall. (1932) Origin of tetraploid shoot from the region of a tumor on tomato. Science, 76, N 1963, p. 144.

Kostoff, D., J. Kendall. (1934) Studies on polyploid plants. III Cytogenetics of tetraploid tomatoes. Gartenbauwiss., 9, 20-44.

Kostoff, D., A. Orlov. (1938) The size of the chloroplasts in euploid forms in Nicotiana and Solanum. Sb. Pamyati Acad. V. I. Lyubimenko, Kiev, 443-446.

Kostoff, D., M. Sarana. (1939) Heritable variations in Nicotiana tabacum L. iduced by abnormal temperatures and their evolutionary significance. Journ. Genet., 37, 499-547.



Addendum: We attach as supplement a missing chapter on the history of botanical science in Bulgaria. Previously, an interested reader should consult some related materials from the booklist cf., "G. Genchev. Problems of Modern Genetics. Sofia, 1965", and "G. Genchev. Genetics ~ Problems, Achievements and Perspectives. Sofia, 1978"; albeit, the latter were written before the former general conclusions on botanics with its three semi-branches of  morphology-anatomy, embryology-cytology and physiology-biochemistry.

Herewith, we continue our story on the development of genetics (cyto-genetics) in this country and lead the narrative to the formal biological conference "On the state of biological science in Bulgaria" (1949) cf., "T. Lysenko. On the Estate of Biological Science /translated by I. Panchev/. Sofia, 1948" from the booklist. On this conference, which took part one year after a similar forum in the U.S.S.R., three bulgarian geneticists were subjected to formal retribution and their works discarded for the sake of the progressive inclination in biology directed by T. D. Lysenko. Those three bulgarian scholars were Prof. M. Christov, Prof. G. Gentchev, and Prof. D. Kostov. None of their published works were given allowance to libraries or scholarly circulation. For some half-a-decade bulgarian genetic science was doomed to be out of mainstream scientific theory and paradigmatic international research.

We write those several lines as small retribution to the victims of communist science:

Prof. Mihail Christov (1895-1960) is the first professional geneticist, cytologist and embryologist in Bulgaria. Has studied in Berlin and Halle in the 1920s. From 1929 is head of Department of Agricultural Botany in the Faculty of Agronomy and Forestry, where a score of students make their developments in the field of applied-theoretical genetics and agro-biology. Published the first textbook in genetics (1936). After World War II is subjected to denunciation until death.

Prof. Gencho Gentchev (1906-1990) is the longest lived bulgarian geneticist from the classical milieu. In the light of contemporary archival research it could be stated that since his "Textbook of Genetics" (1947), everything else wearing his signature have been faked by agents of scientific-technical intelligence. Otherwise it would appear that he was a humble collaborative to the governing clique that copied with docility materials sent from Moscow. For the sake of this presentation and we stick to the facts obtained from the archive until year 1949. Besides the many foreign publications in referred journals, G. Gentchev spent two years of specialization at Lund University, Sweden, with Prof. A. Gustafsson (1939-1940).

Prof. Doncho Kostov (1897-1949) is the most productive cyto-geneticist in the period before World War II. He left more than 200 publications, from which some 50 works in English language. D. Kostov was the only scholar that hardly worked in his home country. From 1926 to 1929 ~ he specialized as Rockefeller Foundation student at Bussey Institution, Harvard University, with Prof. E. M. East. From 1932 to 1939 ~ he spent his time working with Prof. N. I. Vavilov, at the Leningrad Institute of Genetics; the latter was an ark-enemy of T. D. Lysenko and was purged in the epoch of Stalinization. Maybe because of those relations and Prof. D. Kostov was a political corpse already at the eve of communist era in Bulgaria, ditto.


Pictures 1, 2 & 3: Sample illustrations on the text above.

(i). Prof. Mihail Christov (1895-1960) is the first professional geneticist, cytologist and embryologist in Bulgaria.


(ii). Prof. Gencho Gentchev (1906-1990) is the longest lived bulgarian geneticist from the classical milieu.


(iii). Prof. Doncho Kostov (1897-1949) is the most productive cyto-geneticist in the period before World War II.



Copyright 2009 by the author.