With a few exceptions, the characteristic problem of cultivation of plant explants in in vitro cultures is a low production of secondary metabolites by these cultures. One of the methods, which can achieve an increase in the production of natural substances in in vitro cultures, is elicitation of cell cultures. The effect of the biotic elicitor Pseudomonas aeruginosa in the form of a homogenate and an aqueous suspension of dead cells on the production of anthracene derivatives by the tissue culture of Rheum palmatum L. of different age and origin was examined. The culture was cultivated on a Murashige-Skoog medium with an addition of 10 mg.l -1 of a-naphthylacetic acid. The maximal content of anthracene derivatives found by photometric determination according to PhBs 4 was demonstrated in an eight years old culture (1.027 %) after sixhour elicitation with an aqueous suspension of dead cells of Pseudomonas aeruginosa (1.7 mg of dry matter/1 ml of solution). The culture newly derived from the root of the intact plant Rheum palmatum L. responded to elicitation more sensitively than the culture derived from the seed; nevertheless the content of anthracene derivatives was lower than in the eight years old culture.

        Key words: tissue culture – Rheum palmatum L. – anthracene derivatives – biotic elicitation – Pseudomonas aeruginosa