The effect of copper ions on submerged hornwort (<i>Ceratophyllum demersum</i> L.)

This article presents the results of a study of the effect of copper ions at concentrations of 0,01–0,16 mg/dm³ in laboratory conditions on the stability of the highest aquatic plant, the submerged hornwort. Despite the fact that copper is a biophilic element, all the studied ion concentrations of this element had a negative effect on plant weight gain and the value of the relative parameter of delayed chlorophyll fluorescence already on the first day of exposure. During a seven-day toxicological experiment, the suppression of plant growth when exposed to a toxicant increased. The greatest decrease in the relative parameter of delayed fluorescence compared with the control in all studied concentrations of copper ions was observed on the first day of the experiment. However, after a long period of stay of the hornwort in a toxic environment, its partial adaptation occurs, as a result of which some parts of this plant retain photosynthetic activity. It was found that plants retain their viability up to a concentration of 0,02 mg/dm³ corresponding to 20 MPC in the waters of fisheries facilities. Concentrations of 0,04 mg/dm³ and higher already on the first day led to the loss of leaves. The plant's resistance to the action of copper ions allows it to be considered as a potential phytoremediant of waters contaminated with compounds of this element.