Sachs, Julius von (1832-1897) was a German botanist, a scientist who studies plants. Sachs made important contributions in plant physiology, the study of the processes that enable plants to grow and reproduce.

Sachs was born on Oct. 2, 1832, in Breslau, Germany (now Wroclaw, Poland). He had eight brothers and sisters. His father worked as an engraver, but the family was poor. Sachs attended schools in Breslau from 1840 to 1850. He was an excellent student, but he had to drop out of school after the deaths of his father in 1848 and mother in 1849 left his family with no income.

In 1850, Sachs went to Prague, Austria-Hungary (now Czech Republic) with the Czech physiologist J. E. Purkyne, for whom he worked as. a personal assistant. Sachs studied at the University of Prague from 1851 to 1856. During this time, he conducted research in biology (the scientific study of living things), and he wrote 18 articles describing this research for a local scientific journal. About 1854, Sachs showed that the sugar glucose is produced in plants in the green substance called chlorophyll but that the glucose is stored as starch.

Sachs received a Ph.D. degree from the University of Prague in 1856. He then became a lecturer in plant physiology at the university. From 1858 to 1859, he did research in which he discovered that oil stored in seeds was transformed into starch used to feed the plant and help it grow.

In 1859, Sachs returned to Germany, where he held a series of academic positions. He began as assistant in plant physiology at the Agricultural and Forestry College in Tharandt, near Dresden. In 1860, he began to help edit the multivolume Handbuch der physiologischen Botanik (Handbook of Plant Physiology). He also did experiments that involved placing plants in a pure solution of nutrients and observing their growth. From 1861 to 1867, he taught botany at the Agricultural College in Poppelsdorf, near Bonn. He became professor of botany at the University of Freiburg in 1867. In 1868, he became professor and chair of the botany department at the University of Würzburg, where he remained for the rest of his career. He was elected rector (president) of the university in 1871.

Throughout the 1860's, Sachs continued his research on plant growth and development. He was especially interested in the effects of light and heat on plants and in how plants get their food. Sachs showed that in plants that contain chlorophyll, the chlorophyll is not spread throughout the whole plant. Instead, it is contained in tiny cell bodies. These cell bodies later became known as chloroplasts. Photosynthesis, the process by which plants make food, takes place in the chloroplasts.

In the 1870's, Sachs studied growth mechanisms in plant roots and the ways in which plants are affected by their environment. He noticed that a plant may display a bending movement called a tropism in response to an outside force. In particular, he observed geotropism (bending caused by gravity), heliotropism (bending caused by light, known today as phototropism), and hydrotropism (bending caused by water).

In Sachs's time, botanists used microscopes but had few other reliable tools to help them in their work. Sachs invented or improved upon much of the equipment that is commonly used today. For example, he invented the clinostat, a device used to measure the effects of gravity, light, and other outside forces on the movement of growing plants.

Sachs wrote a number of books based on the knowledge he gained through his extensive research. His Lehrbuch der Botanik (Textbook of Botany) was published in 1868 and quickly became a leading source of information in that field. The book had great influence in Europe and the United States by emphasizing the use of living plants in teaching botany. Other books by Sachs include Geschichte der Botanik vom 16. Jahrhundert bis 1860 (History of Botany from the Sixteenth Century to 1860; 1875), Vorlesungen über Pflanzenphysiologie (Lectures on Plant Physiology; 1882), and Gesammelte Abhandlungen über Pflanzenphysiologie (Complete Discourse on Plant Physiology; 2 volumes, 1892-1893). Illustrations based on his drawings often were included in textbooks by other authors. Sachs also published more than 90 articles in professional journals throughout his career.

Sachs was internationally recognized for his work. He was elected to the National Academy of Sciences of the United States in 1895.

Sachs died on May 29, 1897, in Würzburg.