ESTABLISHMENT AND CHARACTERIZATION OF PHOTOSYNTHETIC HAIRY ROOT CULTURES OF DATURA-STRAMONIUM

Twelve different lines of Datura stramonium (normal and hairy) root cu ltures were subjected to conditions which induce photoautotrophy. Two of the hairy root lines responded to induction, showing clearly a dimi nished growth rate when compared to heterotrophic cultures, an increas e in chlorophyll, a net O-2 evolution, CO2 fixation, and de novo synth esis of the ribulose 1,5 biphosphate carboxylase enzyme. A time course of growth and tropane alkaloid levels in the tissue and medium, revea led a correlation between the development of the photosynthetic appara tus and the increase in scopolamine. Although normal cultures did not grow photosynthetically, they showed some greening response under the first step of the induction. The correlation between development of ph otosynthesis and increase in scopolamine synthesis were corroborated w ith normal root cultures. This experimental model is used for the basi c study of the regulatory enzymes involved in the biosynthesis of trop ane alkaloids, as well as for the study of their mechanisms of transpo rt.