University of Konigsberg, Konigsberg, Germany
Klebs studied the natural sciences, philosophy, and art history at the University of Konigsberg.
Klebs received his education in the small East Prussian city of Wehlau, entering elementary school in 1864 and graduating from the Realgymnasium in 1874. He then studied the natural sciences, philosophy, and art history at the University of Konigsberg. During his first semester he composed a prize essay in philosophy; but in preparing a study of the Desmidiaceae, an algae family, his interest was drawn to botany.
Klebs served as an assistant to Anton de Bary at the University of Strasbourg (1878-1880). Subsequently, he became an assistant to the leading plant physiologists of the time, Julius von Sachs at Wurzburg and Wilhelm Pfeffer at Tubingen. In 1883 he qualified as a lecturer at Tubingen. Klebs was appointed a full professor at Basel in 1887 and obtained the same position in 1898 at Halle and in 1907 at Heidelberg, where he was simultaneously named privy councilor. Klebs was rector of the University of Basel for a year and twice dean of the Science and Mathematics Faculty at Heidelberg. Shortly before his death, he was elected rector of the University of Heidelberg.
In his scientific work, which was stimulated primarily by de Bary, Klebs at first concentrated on systematics among the algae and fungi, but he soon turned his attention to the cellular and reproductive physiology of these plants. His important discoveries in these areas include the fact that the presence of the nucleus is necessary for the formation of a cell wall.
Klebs’s principal work began with his extensive investigations of developmental variation among both lower and higher plants, particularly of the way in which variation is brought about through alteration of environmental factors. He defined their combined activity as follows: “All variations of a species are generated by the external environment in that it materializes, through its effect on the inner conditions, the powers lying dormant in the specific structure.” The crucial innovation of this conception is the distinction between the unchangeable specific structures (the genetic endowment) of the cell and the internal factors that are altered in response to external conditions.
Klebs was a member of many scientific academies, including the Heidelberg Academy for Sciences and Humanities and the Academy of Sciences of Turin.
On March 20, 1888, Klebs married Luise Charlotte von Sigwart of Tubingen; they had three children.