Histochemical localization in Ruta graveolens cell cultures: elucidating the relationship between cellular differentiation and furanocoumarin production

Cell cultures of Ruta graveolens L. were used as a model system to study the relationship between cellular organization and furanocoumarin production. Relative contributions of individual cells were traced using a combination of biochemical and localization techniques in three types of cell cultures: dispersed, aggregated, and organized. The proportion of relative furanocoumarins produced varied with the organization level in cultures. Productive population in dispersed cell culture was 10% which increased to 17% and to 35% in aggregated and organized cell cultures, respectively. Large cell clusters accumulating furanocoumarins were restricted to organized cell cultures. In these lines, sites for psoralen, bergapten, and xanthotoxin accumulation were spatially separated from each other, which has been reported for the first time. Variation in production was due to change in relative size of productive population in the three types of cultures studied. A model has been proposed for differential furanocoumarin producing ability of cells based on differentiation levels.