WIESNER, JULIUS VON

WIESNER, JULIUS VON (1838–1916), Austrian botanist. Born in Moravia, Wiesner showed an early bent for botany, publishing his first scientific paper, on the flora of the vicinity of Brno, when he was hardly 16 years old. After receiving his Ph.D. at the age of 22, he taught plant physiology at the Vienna Polytechnic Institute and at Mariabrunn. In 1873, Wiesner   was made professor of plant anatomy and physiology at the University of Vienna, where he remained for 36 years, until his retirement in 1909. Wiesner was one of the founders of modern economic botany. His major work in this area was Die Rohstoffe des Pflanzenreiches (1873), a comprehensive treatment of the world's plants as sources of gums, resins, fibers, and other economically valuable products. No less outstanding were Wiesner's contributions to basic botanical science. He did important research on the effect of light on plants, on the process of chlorophyll formation, and on the power of movement in plants. In his Die Elementarstructur und das Wachstum der lebenden Substanz (1892), Wiesner put forward a theory (now only of historical interest) that the cell is not the ultimate unit of life but is composed of simpler elementary units, which he called "plasomes." -BIBLIOGRAPHY: K. Linsbauer et al. (eds.), Wiesner und seine Schule (1903); Molisch, in: Berichte der deutschen botanischen Gesellschaft, 34 (1916), 88–99. (Mordecai L. Gabriel)