Effect of the Level of Irradiance on Growth and Content of Photosynthetic Pigments of Canadian Elodea (Elodea canadensis) in Model System 'Water-Bottom Sediments'

Bioassays based on aquatic plants are a convenient tool for studying the quality of bottom sediments. One of the stages in the development of a bioassay is the selection of optimal growth conditions for indicator plants in a model test system. Response of indicator physiological endpoints of Canadian waterweed (Elodea canadensis) to light flux density was investigated to determine optimal irradiance level in a “water – sediment” model system, proposed previously for contact bioassay of natural bulk bottom sediments. Based on the response of shoot and root growth (length and weight), and concentration and ratio of photosynthetic pigments (chl. a, chl. b, and carotenoids) of Elodea to the change of light flux density, no limitation or inhibition of growth and photosynthesis of Elodea was revealed at light flux density from 56 to 143 μmol quanta ∙ m-2 ∙ s-1. Hence, the level of irradiance within this range can be recommended for use in the experimental system proposed for bioassay of bulk bottom sediments using E. canadensis as an indicator