The content of organic and biogenic substances in the leaves of Elodea canadensis Michx., Hydrocharis morsus-ranae L. and Potamogeton perfoliatus L. and the factors determining their concentration

This paper discusses the peculiarities of changing the content of total nitrogen, proteins and organic substances in the assimilation organs of three species of hydrophytes (Elodea canadensis Michx., Hydrocharis morsus-ranae L., Potamogeton perfoliatus L.) growing at different levels of pollution of the urbanized reservoir. The work presents the results of comparison of the river pollution within the city of Yoshkar-Ola. Local areas of pollution of the urban water body with nitrogenous compounds, suspended solids and iron have been identified (a comparison with the maximum permissible concentration, a calculation of the water pollution index, an analysis of variance). The main sources of pollution of the river were sewage and storm water. The studies have shown that the leaves of submerged rooting hydrophytes have more nitrogen and proteins than the free-floating hydrophyte. In the leaves of H. morsus-ranae, the concentration of organic substances is higher than in E. canadensis and P. perfoliatus, which is a feature of the structure and functioning of plants. With an increase in the anthropogenic load on the urban reservoir, the ratio of biogenic and organic substances in the leaves of hydrophytes changes: the concentration of total nitrogen increases and the content of total protein and organic substances decreases, which, apparently, indicates a change in the direction of transport of organic substances and inhibition of synthesis processes under conditions of pollution of the reservoir. The obtained materials can be used to organize biomonitoring of the state of surface sources subjected to man-made pollution by the effluents of urbanized territories.