Explant cultures have been, besides other things, used for elicitation, which is an economically advantageous method making use of protective mechanistu of plants to increase the production of secondary metabolites. The present study investigated the effect of 6, 12, 24, 48, 72, and 168 hours lasting action of four concentrations of the biotic elicitor chitosan on the production of anthracene derivatives by the callus and suspension culture ofRheum palmatum L. The culture was cultivated on a Murashige-Skoog medium with an addition of 10 mg.l-1 of a-naphthylacetic acid. A positive effect on the production was exerted in particular by elication ofthe suspension culture. The maximal content of anthracene derivatives (1.181 %), found by photometric determination according to PhBs 4, as demonstrated after 24-bour action of a chitosan solution of a concentration of 1 mg/30 tul of the medium. In contrast to the suspension culture, the production of anthracene derivatives in the callus culture was influenced by elicitation only in the minimal way.

        Key words: Rheum palmatum L. - callus and suspension culture - anthracene derivatives - biotic elicitation - chitosan