The Effect of Bacillus cereus on the Digestion of Prey by Carnivorous Plants

establishment of plant organ cultures. Since then protocols have been developed for cultivating many genera of carnivorous plants in vitro, including: Aldrovanda, Byblis, Cephalotus, Darlingtonia, Dionaea, Drosera, Drosophyllum, Genlisea, Heliamphora, Nepenthes, Pinguicula, Sarracenia, and Utricularia. However, the purposes for growing carnivorous plants in vitro are quite diverse. It is useful to subdivide these in the following categories: commercial mass propagation ex situ conservation physiological examination under sterile conditions, especially for understanding the nutrition of carnivorous plants study and production of secondary metabolites. The applied techniques and the exploited mechanisms for reaching a particular goal are consequently as different as the purposes themselves. For the first two categories clonal propagation is achieved using techniques which minimize somaclonal variation e.g. the shoot tip culture or the single node technique. Organ cultures are used for the third category, whereas undifferentiated fast growing cell cultures are preferred for the production of natural products. In our laboratory, we have established in vitro cultures of several carnivorous plants and their close non-carnivorous relatives in the order Nepenthales (incl. Polygonaceae, Plumbaginaceae, Nepenthaceae, Ancistrocladaceae, Dioncophyllaceae, Drosophyllaceae, and Droseraceae) for the purpose of studies on their secondary metabolism. The members of this group are marked by their ability to produce acetogenic quinones like plumbagin, 7-methyljuglone, or emodin. Furthermore, the families Ancistrocladaceae and Dioncophyllaceae (incl. Triphyophyllum peltatum) are notable for containing the unique naphthylisoquinoline alkaloids (Bringmann & Pokorny 1995) investigated in our group. First experiments with callus cultures have shown that acetogenic metabolite production can be elicited by exogenous stimuli. The carnivorous syndrome of one of the above mentioned species, viz. T. peltatum has hitherto not been demonstrated conclusively because the uptake of organic matter was not proven experimentally. For this reason labelled alanine (an amino acid commonly found in animal protein) was fed to the insecttrapping organs of T. peltatum during a field trip to the Taï National Park in Ivory Coast (Bringmann & al. 1996). After GC/MS analysis of extracts from different parts of fed and control plants, incorporation and redistribution of the label was demonstrated unambiguously. T. peltatum is a part time carnivorous plant with all required attributes.