Ekaterina Viktorovna Morachevskaya

Th e methodology for biodiagnostics of the ecological state of soils and other environmental objects involves the use
of two approaches: bioindicative observations in situ and biotesting of samples, carried out according to standard methods in controlled laboratory conditions ex situ. An integrated assessment of soils on an interdisciplinary basis in accordance with the international standard ISO19204-2017 makes it possible to diagnose of soils “health” based
on biotic parameters in the course of natural environmental observations, ecotoxicity indicators, which are supplemented
by the results of quantitative chemical analysis (TRIAD methodology). For soils, indicators of the state of higher plants and microbial communities, especially in agroecosystems, are of paramount importance. The article analyzes the advantages and limitations of well-known methods of phytoindication, laboratory phytotesting, soil
respiration, structural and functional indicators of microbiota diversity and bacterial biosensors. Th e responses of living systems to the same pollutant content largely depend on the carbon content of organic matter. The existing regulatory framework for the ecological assessment of the biological state of soil ecosystems practically does not take into account this, as well as the level of mineralization and pH of the analyzed objects. For an adequate assessment of the ecological quality of soils, it is proposed to improve the methods of measuring toxicity by more targeted recommendations for application (for example, for certain gradations of humus content, mineralization, pH).

The article considers the possibility of foliar application of amino acids (proline, methionine and lysine) for the regulation of metabolism and the formation of stress resistance in plants contaminated with heavy metals (cadmium). In the green pot experiment, stress was created due to the introduction of Cd(NO3)2 into the soil at a dose of 10 mg·kg–1, which corresponds to 5 permissible concentration (SanPiN 1.2.3685-21). In an experiment with «Nur» barley, the effect of these amino acids on biomass, the content of total and protein nitrogen in leaves, the content of pigments and their ratios (Cl a, Cl b, carotenoids, Cl a / Cl b) were studied. Foliar treatment of plants with amino acids in the absence of stressful conditions was accompanied by a significant increase in aboveground biomass. The use of proline, methionine and lysine in conditions of high Cd concentrations in the soil had a positive effect on barley biomass and ear formation. All plants treated with proline and lysine showed an increase in the content of all pigments (Cl a, Cl b, carotenoids) compared with the control. Methionine had a positive effect on the chlorophyll content precisely under stress, whereas in the absence of stress, the pigment content in the plant decreased. In the Cd-contaminated variants, there was a decrease in the content of both total and protein nitrogen in barley, which indicated a violation of metabolic processes in the plant under stress. Foliar treatment with amino acids during the tillering phase is accompanied by an increase in nitrogen content both under stress and without it.