Lemna minor in studying the combined effects of Mn

\nThe work investigated the combined effect of pyrocatechol (0.001n and 0.1n) with KMnO4 (0.001n and 0.01n) on the Lemna minor. The range of ratios of equivalent concentrations of metal ion and pyrocatechol was from 1:100 to 10:1. It was shown that individual solutions of pyrocatechol exhibited a pronounced damaging effect towards L. minor starting from a concentration of 0.1n, and KMnO4 – from 0.01n. It was revealed that the toxic effect of a 0.1n solution of pyrocatechol decreased with the addition of 0.01n and, to a greater extent, 0.001n solutions of KMnO4. A significant reduction in the damaging effect of 0.01n KMnO4 solution was established when adding 0.001n pyrocatechol to a 10-fold excess of the equivalent concentration of potassium permanganate (2.0-2.4 times). On the contrary, the yield of electrolytes increased in equinormal 0.001 n mixtures of solutions of pyrocatechol and a metal compared to individual solutions. Based on the toxicological data, analysis of UV-VIS spectra, an attempt was made to explain the mechanisms of interaction between pyrocatechol and KMnO4 during their action on plant. The data can be useful for understanding the processes of self-purification of water bodies, be of interest when using plants to clean water bodies, predicting environmental risks.\n