Gregor Kraus

Gregor Konrad Michael Kraus , also Gregor Conrad Michael Kraus (born May 9, 1841 in Bad Orb , † November 14, 1915 in Würzburg ) was a German botanist , palaeobotanist and university professor. Kraus is considered to be one of the founders of microclimatology and experimental ecology. Its official botanical author's abbreviation is " Kraus ".

Life

The son of a teacher attended high school in Aschaffenburg and studied from 1860 medicine at the University of Würzburg , where he in 1866 with a thesis about the construction of dry Pericarpien Dr. phil. received his doctorate. He then worked as a research assistant to Julius Sachs at the University of Bonn and moved with him to the University of Freiburg . 1867 Habilitation at the University of Würzburg on the subject of tissue tension in the trunk and its consequences and appointment as a private lecturer in Würzburg. From 1868 he was a scientific assistant at the Botanical Institute of the University of Leipzig . In 1869 he was appointed full professor and director of the botanical garden at the University of Erlangen , where he worked until 1872. In 1872 he succeeded Anton de Bary as full professor and director of the Botanical Garden at the University of Halle . In 1874 he was elected a member of the Leopoldina . In 1898 he succeeded Julius Sachs at the University of Würzburg.

research

His scientific interest was initially in the anatomy of plants, especially fossil and recent trees. Because of his special knowledge in this area, Kraus was used, among other things, to determine the driftwood that the Second German North Pole Expedition , led by Carl Koldewey , had collected in 1869 and 1870. As one of the first paleobotanists, Kraus also dealt with the anatomical characteristics of fossil softwoods. He was able to depict the fine cellular structure of these fossils using splinters of Keuper pebble wood from the deposits of the Main. In Erlangen and Halle he dealt with the physiology of plants, gradually developing ecological questions and thus becoming one of the pioneers of ecophysiology . First he researched the properties of chlorophyll, using new methodological approaches such as spectral analysis . With his studies on the metabolism of the Crassulaceae he touched on aspects of the water balance of plants, in his work on the physiology of tannins he devoted himself, among other things, to the ecological importance of this class of substances. Kraus undertook several research trips, for example to Java in 1893/1894 and to India in 1896/1897 .

As director of the Botanical Garden at the University of Halle , he introduced a new concept in which he arranged the plants according to their relationship and physiognomic criteria. He later introduced this type of presentation in Würzburg, and it is now the norm in many botanical gardens. Ecological aspects also came into play with him, for example by setting up a large complex of alpine plants, a collection of German salt plants. A foundation of the widow of the industrialist Carl Adolph Riebeck ensured that the stock of cold house plants was expanded .

Kraus is considered to be one of the founders of microclimatology. He summarized his research results in this area in his book Climate and Soil in the Smallest Space , published in 1911 : Attempting to Exactly Treat the Location on the Wavy Limestone , which is now considered to be one of the first plant-ecological works, in which the conditions of existence of plants using chemical and physical methods described and analyzed. In doing so, he also created the basis for the experimental-ecological analysis of plant distribution. In addition, with his investigations, Kraus became a role model for careful site analysis and gave a significant impetus for the development of the then still young science, ecology.

The well-known fact that within a seemingly uniform climatic area in a confined space there are often very considerable differences in terms of temperature, air movement and relative humidity, and that this can be seen in a change in vegetation, was known even before Kraus. His merit lies in the fact that he recorded these conditions for the first time in a section of the landscape, namely the Muschelkalkgebirge of the central Main Valley, using precise research methods over a long period of time.

During his investigations, he carried out numerous chemical soil analyzes, examined the soil profile and the grain size of the soil, i.e. the proportion of skeleton and fine soil, the water content and the temperature of the soil as well as temperature and wind at different heights above the ground.

It was shown, for example, that the “limestone vegetation” is less dependent on a specific carbonate content in the soil, but that its formation is primarily determined by the physical soil conditions. Limestone soils usually have a high proportion of skeleton. Such soils are the drier and the faster they warm up, which has a significant impact on the plant community.

He also found out from his exact temperature measurements that the daytime temperature in the lowest layers of air immediately above the ground is often more than 10 ° C higher than the climate measurements suggest, which measure the air temperature as standard at a height of 2–3 m above the ground.

Kraus carried out his measurements and experiments on the dry, hot shell limestone slopes near Gambach , buying two permanent areas of a slope that was not cultivated at the time. These properties later became the property of the Natural Science Association of Würzburg and became the centerpiece of an area that is now protected.

Works

• The botanical garden of the University of Halle . (1888-1893).
• History of the introduction of plants into the European botanical gardens . 1894.

Fonts

• Gregor Kraus: Microscopic examination of the construction of living and prehistoric conifers. In: Würzburger Naturwissenschaftliche Zeitschrift , 5, pp. 144–200, Würzburg 1864.
• Gregor Kraus: About the construction of dryer pericarpies . In: Yearbooks for Scientific Botany , Vol. 5, 1866. Engelmann, Leipzig, 64 p., Ill. Zugl .: Würzburg, Univ., Diss.,.
• Gregor Kraus: The tissue tension of the trunk and its consequences . In: Botanische Zeitung , vol. 25, 1867. Gebauer-Schwetschke, Halle, 30, 40 p .: Ill. Zugl .: Würzburg, Univ., Habil.-Schr.
• Gregor Kraus: To the knowledge of the chlorophyll dyes and their relatives: spectralanalytischeUntersuchungen. Schweizerbart, Stuttgart 1872, VIII, 131 pp.
• Gregor Kraus: Contributions to the knowledge of fossil woods . Niemeyer, Halle 1882, 33 p. Graph. Darst.
• Gregor Kraus: About metabolism in the Crassulaceae . Niemeyer, Halle 1886, 86 pp.
• Gregor Kraus: The Botanical Garden of the University of Halle . Engelmann, Leipzig 1888-1893
• Gregor Kraus: Basic lines for a physiology of the tannin . Engelmann, Leipzig 1889, 131 pp.
• Gregor Kraus: Christian Wolff as a botanist . Speech given on the assumption of the rectorate of the University of Halle on July 12, 1891. Max Niemeyer, Halle 1892, 17 pp.
• Gregor Kraus: About the water distribution in the plant . IV. The acidity of the cell sap . In: Abhandl. natural research. Ges. Halle , 1893, p. 143.
• Gregor Kraus: History of the introduction of plants into the European botanical gardens . Engelmann, Leipzig 1894, 73 pp.
• Gregor Kraus: Why the botanist has to go to the tropics . In: Festschriften of the 4 faculties of the Univ. Halle , 1894, pp. 209-219.
• Gregor Kraus: Johann Michael Fehr and the Grettstadter Meadows . In: Negoti. d. phys. -med. Society zu Würzburg , NF, Volume 34,10, 1902. Stuber, Würzburg, pp. 304-342.
• Gregor Kraus: Anemometrics from Krainberg near Gambach. After a lecture in the physik.-med. Society . In: negotiations of physik.-med. Gesellschaft zu Würzburg , NF, Volume 37, 1905, No. 4: From the plant world of Lower Franconia , with panels IV-VII, pp. 163–202. Stuber, 40 p., Ill.
• Gregor Kraus: Vicia Orobus DC. and their heterotrichia . With 2 plates. In: Negotiations of the physik.-med. Gesellschaft zu Würzburg , NF, Volume 38, No. 7, 1906, From the flora of Lower Franconia. Stuber, Würzburg, 14 pp., Ill., Pp. 242-254
• Gregor Kraus: The Sesleria dump . In: negotiations of physik.-med. Gesellschaft zu Würzburg , NF, Volume 38, No. 10, 1906, 8. From the flora of Lower Franconia . A. Stuber, Würzburg, 21 pp.
• Gregor Kraus: About the nanism of our limestone plants . In: negotiations of physik.-med. Gesellschaft zu Würzburg , NF, Volume 38, No. 4, 1906, 6. From the flora of Lower Franconia . A. Stuber, Würzburg, pp. 103-134.
• Gregor Kraus: Experiences about soil and climate on the Wellenkalk: exquisite communication . 1906, pp. 20-34.
• Gregor Kraus: Gynaeceum or Gynoeceum? and other linguistic . In: negotiations of physik.-med. Gesellschaft zu Würzburg , NF, Volume 39, 1907. A. Stuber, Würzburg, pp. 9-14.
• Gregor Kraus: Soil and climate in the smallest of spaces: Attempt to precisely treat the location on the limestone . Fischer, Jena 1911, 184 pp., Ill., Graph. Darst.

literature

• Uwe Buschbom:  Kraus, Gregor. In: New German Biography (NDB). Volume 12, Duncker & Humblot, Berlin 1980, ISBN 3-428-00193-1 , p. 686 ( digitized version ).
• Hans Kniep : Commemorative speech for Gregor Kraus on May 31, 1916 . With 1 portrait. In: Negotiations of the physical-medical society in Würzburg , NF, Volume 44, No 6174.-196, 1916.
• Hans Kniep (Hrsg.): To the knowledge of the Würzburg rose flora: Nachgelassene Schriften / by Gregor Kraus . In: Negotiations of the physical-medical society in Würzburg , NF, Volume 45, No 1, 1917. Kabitzsch, Würzburg, 29 pp.
• Fritz Kümmel (Ed.): 300 years of the botanical garden of the Martin Luther University Halle-Wittenberg . Hall 1998, 78 pp.
• Dieter Mollenhauer (ed.), Klaus Hemm: Gregor Kraus: a botanist from the Spessart and his plants . With contribution from Klaus Hemm… With a self-written "Life picture" by Gregor Kraus for his fiancée. 1st edition. Verlag Orbensien, Bad Orb 2005, ISBN 3-927176-20-6 , 111, 52 S., Illustrated sheets on Bad Orb's history and culture , Volume 1.

Web links

• Literature by and about Gregor Kraus in the catalog of the German National Library
• Author entry and list of the described plant names for Gregor Kraus at the IPNI
• Entry on Gregor Kraus in the Catalogus Professorum Halensis