SACHS, JULIUS (1832–1897), German botanist. Born in Breslau of a poor family, he was encouraged in his studies by the Czech physiologist Johannes Evangelista Purkinje (1787–1869), then at the University of Breslau. When Sachs was 18, Purkinje moved to Prague, and he invited Sachs to come to his institute as an assistant. After obtaining his degree at the University of Prague, Sachs went to Tharandt, where first he taught botany at the forestry school; in 1861 he was appointed professor at the agricultural school at Poppelsdorf, near Bonn. In 1867 Sachs became professor of botany at Wuerzburg, remaining for nearly 30 years.
Sachs held an important place in the history of biology, both as a teacher and as a researcher. His textbooks, Handbuch der Experimentalphysiologie der Pflanzen (1865) and the Lehrbuch der Botanik (1868; Textbook of Botany, 1875), widely influenced the teaching of botany. Sachs's personal influence as a teacher was equally great. Under his genial and enthusiastic leadership, Wuerzburg became an international center for plant physiology, where some of Europe's most eminent botanists were trained.
Sachs has been called the creator of experimental botany. Among Sachs's noteworthy contributions were his demonstration that starch is the first perceptible product of photosynthesis and that it is translocated from the leaf in the form of sugar. Sachs was the first to demonstrate that the chloroplasts are the site of photosynthesis, and it was he who showed that light is necessary for the synthesis of chlorophyll. Sachs also pioneered in studies of the nutritional requirements of plants; he published the first formula for a standard culture solution, a necessary basis for identifying the mineral elements essential for growth. Sachs introduced the auxanometer, an instrument for quantitatively studying plant growth, and the clinostat, a rotating apparatus by means of which he investigated the plant's response to gravity.
E.G. Pringsheim, Julius Sachs (Ger., 1932).
[Mordecai L. Gabriel]