Abstract
A-5-fold stimulation in alkaloid biosynthesis was achieved by tranfer of cells of Cinchona ledgeriana in suspension culture from a 2, 4-D) and benzyladenine (BA) medium to one containing IAA and zeatin riboside (ZR). Cells at the end of a 28 day period following such a transfer contain over 140 µg alkaloid g-1 fresh weight and nearly 1.4 mg of alkaloid was produced from a 2 g inoculum (equivalent to 1.3 mg day-11-1 culture). The presence of both IAA and ZR was required to give this stimulation in alkaloid biosynthesis. Indoylbutyric acid (IBA) can replace IAA. Increasing the ZR level at the optimum concentration of IBA or IAA gave a further increase in alkaloid accumulation. Whilst these changes in hormonal treatment markedly stimulated overall alkaloid formation they had no major effect on the qualitative composition of the mixture of alkaloids formed.
