Joseph Gottlieb Kölreuter
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Joseph Gottlieb Kölreuter (27 April 1733 – 11 November 1806), also spelled ''Koelreuter'' or ''Kohlreuter'', was a German botanist who pioneered the study of plant fertilization, hybridization and was the first to detect
self-incompatibility Self-incompatibility (SI) is a general name for several genetic mechanisms that prevent self-fertilization in sexually reproducing organisms, and thus encourage outcrossing and allogamy. It is contrasted with separation of sexes among individuals ...
. He was an observer as well as a rigorous experimenter who used careful crossing experiments although he did not inquire into the nature of heritability.


Biography

Kölreuter was the oldest of three sons of an apothecary in
Karlsruhe Karlsruhe ( , , ; South Franconian: ''Kallsruh'') is the third-largest city of the German state (''Land'') of Baden-Württemberg after its capital of Stuttgart and Mannheim, and the 22nd-largest city in the nation, with 308,436 inhabitants. ...
,
Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
, and grew up in Sulz. He took an early interest in natural history and made a collection of local insects. At the age of fifteen he went to study medicine at the
University of Tübingen The University of Tübingen, officially the Eberhard Karl University of Tübingen (german: Eberhard Karls Universität Tübingen; la, Universitas Eberhardina Carolina), is a public research university located in the city of Tübingen, Baden-W ...
under physician and botanist
Johann Georg Gmelin Johann Georg Gmelin (8 August 1709 – 20 May 1755) was a German naturalist, botanist and geographer. Early life and education Gmelin was born in Tübingen, the son of a professor at the University of Tübingen. He was a gifted child and began ...
who had returned from St. Petersburg. Gmelin had an interest in floral biology and he reprinted a work by Rudolf Jakob Camerarius (who also taught at Tübingen) who was the first to demonstrate sexual reproduction in plants. In his inaugural address in 1749 Gmelin talked the need for research on the origin of new species by hybridization. This may have had an influence on Kölreuter. Gmelin died in 1755, and Kolreuter earned his degree and received an appointment at the Imperial Academy of Sciences at
St. Petersburg Saint Petersburg ( rus, links=no, Санкт-Петербург, a=Ru-Sankt Peterburg Leningrad Petrograd Piter.ogg, r=Sankt-Peterburg, p=ˈsankt pʲɪtʲɪrˈburk), formerly known as Petrograd (1914–1924) and later Leningrad (1924–1991), i ...
on 23 December 1755. Here his work included botany as well as the curation of the fish and coral collections. He stayed on until 6 June 1761. From 1759 he experimented on plant hybridization before returning to Germany. He moved to
Calw Calw (; previously pronounced and sometimes spelled ''Kalb'' accordingly) is a town in the middle of Baden-Württemberg in the south of Germany, capital and largest town of the district Calw. It is located in the Northern Black Forest and is a ...
in 1763 and Karlsruhe in 1764 where he was briefly professor of natural history and director of the botanical garden at Baden. He was dismissed from the botanical garden after a dispute with the head gardener in 1783 but stayed as a professor until 1806 when he died.


Researches

Kölreuter followed the standard idea of the period of plants and nature personified by a Creator. He expected patterns, for instance, homogeneity in the male and female contributions to the progeny. He also strongly believed in epigenetic influences which may have been derived from the teachings of C. F. Wolff. The dominant belief during his time was that an offspring was already preformed in the female or the male and that the embryo was developed after sex and the origin decided the offspring's characteristics or similarities to the parent. Kölreuter, however noted a mixing of characters and proposed the idea of “seed matters” (Saamenstoffe). According to Kölreuter there had to be two uniform fluids, male and female semen which combined in the process of fertilization. He believed that equal quantities of the male and female fluid were needed and he therefore examined how much pollen was needed in fertilization of a given number of seeds. In flowers with multiple stigmas, he cut all but one and found that pollinating it was enough to fertilize all the seeds. He examined the action of stigma fluid on pollen. described many plant species, and studied pollen and its transfer. Kölreuter's major works were produced as four reports ''Vorlaufige Nachricht von einigen das Geschlecht der Pflanzen betreffenden Versuchen und Beobachtungen'' (1761), ''Fortsetzung'' (1763), ''Zweyte Fortsetzung'' (1764), and ''Dritte Fortsetzung'' (1766). They were reprinted in 1893 in
Wilhelm Ostwald Friedrich Wilhelm Ostwald (; 4 April 1932) was a Baltic German chemist and philosopher. Ostwald is credited with being one of the founders of the field of physical chemistry, with Jacobus Henricus van 't Hoff, Walther Nernst, and Svante Arrhen ...
's '' Klassiker der exakten Wissenschaften''. Kolreuter's findings are not reported in easy to read sections but are distributed throughout the text. Many parts have not been fully translated to English and this has led to many of the results not being examined well. In all he conducted nearly 500 different hybridization experiments across 138 species and examined the pollen characteristics of over a 1000 plant species. The first documentation of male sterility in 1763 was by Kölreuter, who observed anther abortion within species and specific hybrids. Koelreuter was the first who reported
self-incompatibility Self-incompatibility (SI) is a general name for several genetic mechanisms that prevent self-fertilization in sexually reproducing organisms, and thus encourage outcrossing and allogamy. It is contrasted with separation of sexes among individuals ...
in ''Verbascum phoeniceum'' plants. He also observed
heterosis Heterosis, hybrid vigor, or outbreeding enhancement is the improved or increased function of any biological quality in a hybrid offspring. An offspring is heterotic if its traits are enhanced as a result of mixing the genetic contributions o ...
, that hybrids surpassed their parents. His experimental method included repetitions and controls. He wanted to test if hybrids across species could be fertile. Buffon had used the idea of sterility of crosses as a method of testing species boundaries. Buffon used sterility versus fertility as a criterion for species but he gave up the idea in 1753 when he found fertile hybrids in domestic animals and cagebirds. Linnaeus through his student J. J. Hartmann reported the possibility of new "species" arising from hybridization but Kölreuter was skeptical of the results. In one experiment Kölreuter sat beside a flower from dawn to dusk and shooed away all insects to find that the flower remained unfertilized. He tested a hypothesis by
Jan Swammerdam Jan Swammerdam (February 12, 1637 – February 17, 1680) was a Dutch biologist and microscopist. His work on insects demonstrated that the various phases during the life of an insect— egg, larva, pupa, and adult—are different forms of the ...
that honey was nectar that underwent fermentation in the crop of a bee. Kölreuter collected nectar from many hundreds of orange trees and kept them in vials to evaporate and he reported that it thickened and tasted like honey with time. Kölreuter produced interspecific hybrids - specifically the tobacco plants ''
Nicotiana rustica ''Nicotiana rustica'', commonly known as Aztec tobacco or strong tobacco, is a rainforest plant in the family Solanaceae. It is a very potent variety of tobacco, containing up to nine times more nicotine than common species of ''Nicotiana'' such ...
'' and '' Nicotiana paniculata'' in 1760. The hybrids showed male sterility. He also worked on ''Dianthus'' and ''Verbascum''. He found that reciprocal crossing produced identical results. He also pondered over the commercial applications of hybridization - "''I would wish that I or somebody else would be so lucky someday to produce a species hybrid of trees which, with respect to the use of its lumber, would have a large influence on the economy. Among other good properties such trees might perhaps also have the one that they would reach their full size in one half of the time of normal trees''" (translated by Ernst Mayr). Although Kölreuter conducted a variety of repeated crossing experiments much in the manner of
Gregor Mendel Gregor Johann Mendel, OSA (; cs, Řehoř Jan Mendel; 20 July 1822 – 6 January 1884) was a biologist, meteorologist, mathematician, Augustinian friar and abbot of St. Thomas' Abbey in Brünn (''Brno''), Margraviate of Moravia. Mendel was ...
, his interpretations were based on alchemical notions and he did not seek to examine the nature of heritability or the particulateness of heritable traits. Kölreuter followed an idea from alchemistry that metals were a mixture of mercury and sulphur and considered likewise that an equilibirum of the male and female "seed matters" had a role in deciding the qualities of hybrid offspring. Although Koelreuter did not endorse the
transmutation of species Transmutation of species and transformism are unproven 18th and 19th-century evolutionary ideas about the change of one species into another that preceded Charles Darwin's theory of natural selection. The French ''Transformisme'' was a term used ...
, his hybridisation research influenced the development of evolutionary theory in the eighteenth century.Glass, Bentley. (1960). ''Eighteenth-Century Concepts of the Origin of Species''. ''Proceedings of the American Philosophical Society'' 104 (2): 227-234. The genus ''
Koelreuteria ''Koelreuteria'' , also known as chinese lantern tree, is a genus of three species of flowering plants in the family Sapindaceae, native to southern and eastern Asia. They are medium-sized deciduous trees growing to tall, with spirally arranged ...
'' has been named in his honour.


Works

*
Dissertatio inauguralis medica de insectis coleopteris, nec non de plantis quibusdam rarioribus... Tubingae: litteris Erhardianis
' (1755) *
Vorläufige Nachricht von einigen, das Geschlecht der Pflanzen betreffenden Versuchen
' (1761-1766) *

' (1777)


References

;Bibliography *


External links



{{DEFAULTSORT:Kolreuter, Joseph Gottlieb 1733 births 1806 deaths 18th-century German botanists People from Sulz am Neckar Proto-evolutionary biologists