Growth patterns and alkaloid accumulation in hairy root and untransformed root cultures of Datura stramonium

The aim of this work was to study the possible relationship between alkaloi d production and growth measured as: biomass increase and cellular division frequency, in Datura stramonium in vitro root cultures (hairy root and nor mal cultures). A comparison of growth values on a fresh and dry weight basi s showed that there were differences between transformed and non-transforme d lines. The differential growth between lines occurred due to a real bioma ss increase and not because of water accumulation. On the other hand, the r ate of cell division showed a similar pattern for all lines studied. Theref ore, the differences in growth are not due to different cell division rates , nor to the presence of larger meristems, but to the development and growt h of lateral roots and the presence of active intercalary meristematic zone s in each line. The maximum alkaloid production occurred when the cultures were not growing. This suggests an inverse relationship. Finally, the data support a specific model of growth at the level of cell division in root cu ltures which has not been described before in the literature.