SINOPSIS

The ether oil (4.5% of dry mass of the plant) characterized by a predominance of aristolone (11.12%) and P-asarone (10.18%). was isolated from the rhizome of Acorus calamus L. occurring in Ukraine. At the concentrations of this complex of biologically active substances of 0.45-0.90 mg/L, the growth of cultures of green (Chlorella vulgaris Beijer. and Acutodesmus dimorphus (Turp.) Tsar.) and blue-green algae (Anabaena sp., Microcystis aeruginosa Kütz. emend. Elenk. and Aphanizomenon flos-aquae (L.) Ralfs) was inhibited. This complex of biologically active substances influenced the development of natural phytoplankton. As a consequence, the number of its species, and also its numbers and biomass decreased. Anabaena sp. and Microcystis aeruginosa proved to be most sensitive to the influence of the ether oil. The extracts of the rhizome of Acorus calamus (5 g/L) were more active in relation to phytoplankton than its ether oil at the expense of joint action of terpenes and polyphenols.