Wilhelm Pfeffer
Wilhelm Friedrich Philipp Pfeffer ( born March 9, 1845 in Grebestein near Kassel, † January 31, 1920 in Leipzig ) was a German botanist and plant physiologist. Its official botanical author abbreviation is " pepp. ".
Life and work
William Pepper was the son of a pharmacist. He first visited the Kassel Electoral College, then was an apprentice pharmacist and dropped 18 years the assistants examination. His father woke early his interest in botany and natural sciences. From 1863 he studied chemistry and pharmacy at the University of Göttingen. He heard among other lectures in chemistry at Friedrich Wohler, in physics at Wilhelm Eduard Weber and in chemistry at Rudolph Fittig.
In the latter, he was in 1865 on the theme " On certain derivatives of glycerol and its extension into allylene " Dr. phil. doctorate. He studied pharmacy at the University of Marburg.
He then worked as a pharmacist in Augsburg and in 1866 in Chur / Graubünden, where he worked among others with mosses. Through his uncle, the geologists Gottfried Theobald, he was introduced to the Alps Botany and mountain climbing. Pepper was the fifth person who defeated the Matterhorn.
From 1868/69 Pepper again studied pharmacy at the University of Marburg and closed with the pharmaceutical Staatsprüfung. He then studied at the University of Berlin among others, Alexander Brown and Nathanael Pringsheim, in which he was private assistant. Then Pepper went as a private assistant to Julius von Sachs in Würzburg.
He habilitated in 1871. Works from this period were " The effect of colored light on the decomposition of the carbonic acid in plants " and "The developments of the germ of the genus Selaginella ." After interim period as a lecturer at the University of Marburg pepper worked from 1873 as Associate Professor of Pharmacognosy and Botany at the University of Bonn. In 1877 Pepper full professor at the University of Basel and 1878 at the University of Tübingen. 1880 Pepper became a corresponding member of the Bavarian Academy of Sciences.
In 1887 he was offered a professorship at the University of Leipzig, where he became professor of botany and director of the botanical garden.
Inspired by Julius von Sachs in his time Würzburg, pepper examined on the effect of different colored light on the carbon dioxide assimilation. After that, he met with his work on cell membranes to the phenomenon of osmosis, the physicist Abbé Jean Antoine Nollet had discovered in 1748.
Its osmotic investigations made pepper in his private apartment, at the Institute since no such rooms were available. He developed his namesake Pfeffersche cell, a membrane osmometer. This measuring apparatus consisted of a clay cell whose porous walls were covered with the precipitate membranes described by Moritz Traube in 1867, semipermeable. Pfeffer the cell allowed the quantitative measurement of the osmotic pressure of aqueous solutions for the first time.
Jacobus Henricus van ' t Hoff examined later because of the pepper 's findings, the laws of dilute solutions. He received in 1901 the first Nobel Prize in Chemistry.
Pepper examined many other botanical phenomena, including the movement of the stamens of Centaurea species and chemotactic movements of spermatozoa in mosses and ferns as well as the daily rhythms of leaf and flower movements and the saccharification of maize seedlings.
Together with Julius von Sachs applies Wilhelm Pfeffer as the founder of modern plant physiology.
Student
Numerous student of Wilhelm Pfeffer were later even known botanist. Among them were:
- Carl Correns (1864-1933)
- Frederick Czapek (1868-1921)
- Georg Albrecht Klebs (1857-1918)
- Hans Kniep (1881-1930)
- Ernst Küster (1874-1953)
- Manabu Miyoshi (1862-1939)
- Kurt Noack (1888-1963)
- Arpad Paal (1889-1943)
- Ernst Georg Pringsheim (1881-1970)
- Otto Renner (1883-1960)
- Otto Schmeil (1860-1943)
- Peter Stark (1888-1932)
- Otto Warburg (1859-1938)
William Pepper Price
Since 1992, the German Botanical Society praises about the William Pepper Foundation from the William Pepper price. The Foundation awards the prize, which is endowed with 2,500 euros, young scientists for outstanding contributions to the field of plant sciences.
Writings
- Physiological studies. 1873
- The periodic motions of the leaf organs. 1875
- Osmotic studies. 2 unveränd. Edition 1921 ( Erstaufl. 1877)
- Contributions to the Knowledge of the oxidation processes in living cells. 1889
- About recording and output of unresolved body. 1890
- Studies on the energetics of the plant. 1892
- Pressure and work performance by growing plants. 1893
- Studies on the origin of the sleep movements of the leaf organs. 1907
- The influence of mechanical stress on the inhibition and sleep movement. 1911
- Contributions to the knowledge of the origin of sleep movements. 1915