PHYSIOLOGICAL MARKERS OF DUCKWEED (Lemna minor L.) FOR BIOINDICATION OF WATER POLLUTION WITH COPPER AND DIURON (3-(3,4-DICHLOROPHENYL)-1,1-DIMETHYLUREA)
Abstract. Lesser duckweed (Lemna minor L.) is a cosmopolitan aquatic test plant, its growth and metabolic parameters are useful markers of the influence exerted on living organisms by changes in water quality. We have investigated the influence of water-polluting copper and herbicides on net biomass production, photosynthetic pigment content and efficiency parameters of induced chlorophyll fluorescence of duckweed. Copper decreased biomass production of duckweed only at higher concentrations (100 µM), while diuron inhibited growth even at 10 µM. With respect to the light-harvesting complexes of chloroplasts, the molar ratios between the main types of photosynthetic pigments proved to be the most sensitive markers of the impact of the applied water-polluting agents. In case of water pollution with copper and diuron, the mostly sensitive parameters of induced chlorophyll fluorescence were the potential quantum yield efficiency and the vitality index of photosynthetic apparatus, these parameters being recommended for bioindication of water pollution
