Indole-3-butyric acid in plants: occurrence, synthesis, metabolism and transport Ephraim Epstein11Inst, of Horticulture, ARO, The Volcani Center, Bet Dagan 50 250, Israel; and Jutta Ludwig-Müller22Botanisches Inst., J. W. Goethe Univ., Siesmeyerstrasse 70, Postfach 11 1932, D-6000 Frankfurt am Main, Germany.1Inst, of Horticulture, ARO, The Volcani Center, Bet Dagan 50 250, Israel; 2Botanisches Inst., J. W. Goethe Univ., Siesmeyerstrasse 70, Postfach 11 1932, D-6000 Frankfurt am Main, Germany.