Abstract
The naphthoquinone levels in clones of the sundew species Drosera communis, D. madagascariensis, D. peltata and D. rotundifolia were determined under in vitro, green house, and outdoor growth conditions. D. rotundifolia revealed a lower naphthoquinone content in vitro which rose upon transfer ex vitro. D. communis and D. madagascariensis exhibited higher levels in vitro which decreased in the greenhouse and further under outdoors conditions. Decreased naphthoquinone levels were found in D. peltata when in vitro cultures were moved to the greenhouse, which increased again when the plants were cultivated outdoors. The results underline that in the cultivation of the medicinally useful carnivorous genus Drosera species-specific differences in the biosynthesis of secondary metabolites under different environmental conditions have to be taken into consideration.