Relevance. Many authors note the existence of significant genotypic differences in the assimilation of nitrogen and the accumulation of nitrates by lettuce, point to the additive-dominant nature of the inheritance of the trait. The aim of the work was to evaluate the response of lettuce of various cultivars to mineral nutrition stress created against a nitrogen-deficient background (N0) and with an increased dose of nitrogen (N200).Material and Methods. In a microfield experiment on well-cultivated soddy-podzolic soil, a collection of lettuce varieties belonging to the main cultivated variety types was studied. The varieties differed in geographical origin, early maturity and morphological characteristics.Results. Differences in yield between varieties against the background of N200 were 4.5 times, and against the background of N0 – 5.7 times. Against an increased background of nitrogen nutrition, the highest yield – 2.22-2.64 kg/m2 was formed by the following varieties: All the Year, Quedlinburger Dickkopf, Berlin Yellow, Great lakes. Against a nitrogen-deficient background, Azart and Odessa Kucheryavets varieties stood out in terms of yield, which absorbed soil nitrogen better than others. The content of nitrates in lettuce plants of different varieties varied more strongly when grown on the background of N200 and ranged from 10.7 to 13.6 times (on average over 2 years – 11,2 times), on the control of N0 – 33 times. Varieties accumulating maximum NO3 under conditions of excess nitrogen nutrition were revealed. Lettuce Romaine (Lactuca romana) – 353 mg/kg and White paris cus (198 mg/kg) had a low content of NO3. The period of the maximum increase in biomass also corresponded to the maximum decrease in NO3 in plants. Power function equations were calculated to estimate the rate of change in biomass and NO3 content. The results indicate that there may be some scope for NO3 reduction in lettuce through cultivar selection or breeding.

Anthropogenically altered soils of Saint Petersburg and Luga (Leningrad Region) were investigated for the presence of thermophilic aerobic chemoorganoheterotrophic bacteria, potentially capable of decomposing hydrocarbons at elevated temperatures (60 C). 6 strains of pure spore-forming cultures of bacteria were isolated. Analysis of the nucleotide sequences of the 16S rRNA genes showed that they belong to the genera Geobacillus and Aeribacillus. For the first time, we obtained information on the presence of representatives of the genus Aeribacillus, which are typical inhabitants of hot springs and zones with geothermal activity, in the soils of the regions of Saint Petersburg and the Leningrad Region.

Elaborating on the methods and means of enriching nutrition, including that of plants, with a number of microelements that are vital for humans is now very important due to the unresolved acute problems of micronutrient deficiency and imbalance, which affect the majority of the population of various countries in the world. Promising solutions for the implementation of biofortification in terms of safety, efficiency, size, biocompatibility, and transportability are the water-soluble derivatives of C60 or C70 fullerene. By now, the use of water-soluble fullerenes (C60(OH)22–24 or C70(OH)12–14 fullerenols, C60 fullerene with glycine or with arginine: C60-L-Gly or C60-L-Arg) with various functional groups for plant enrichment is pioneering. Experimental research work was carried out at the agrobiopolygon of the Agrophysical Research Institute under controlled microclimate conditions. This work constituted an assessment of the influence of C60(OH)22–24 fullerenol introduction into the soil on the content of macro- and microelements in the soil and in plants, for example, cucumber, as well as on the plants’ physiological state (photosynthetic pigments, the intensity of lipid peroxidation, the activity of peroxidase and catalase enzymes), growth, and element content. Its aim was to study the possibility of enriching the plants’ production (Chinese cabbage, tomato, and cucumber) with compositions of the fullerene derivatives (C60-L-Gly or C60-L-Arg, C60(OH)22–24 or C70(OH)12–14 fullerenols) and selenium or zinc compounds by introducing them into a nutrient solution or by foliar treatment of plants. It was revealed that the introduction of solutions of C60 fullerenol in various concentrations (1 mg/kg, 10 mg/kg, and 100 mg/kg) into soddy-podzolic sandy loamy soil contributed to the activation of the processes of nitrogen transformation in the soil, in particular, the enhancement of the process of nitrification, and to the increase in the content of mobile forms of some macro- and microelements in the soil as well as of the latter in plant organs, for example, in cucumber plants, especially in their leaves. Along with this, the plants showed an increase in the content of photosynthetic pigments, a predominant decrease in the activity of the oxidative enzyme peroxidase and in the intensity of lipid peroxidation, and an increase in the content of the reducing enzyme catalase. The improvement in the physiological state of plants had a positive effect on the growth rates of cucumber plants. The compositions of solutions of amino acid fullerenes (C60-L-Gly or C60-L-Arg) and sodium selenate as well as C60 or C70 fullerenols and zinc sulfate, selected on the basis of different charges of molecules or functional groups of fullerene derivatives, showed higher efficiency at low concentrations in enriching the plant products of Chinese cabbage, tomato, and cucumber with selenium and zinc, respectively, compared with mineral salts of the indicated elements and control (edible part of Chinese cabbage: by 31.0−89.0% relative to that in the control and by 26.0–81.0% relative to the treatment of plants with a sodium selenate; tomato fruits: by 33.7–42.2% relative to that in the control and by 10.2–17.2% relative to the treatment of plants with a sodium selenate; cucumber fruits: by 42.0–59.0% relative to that in the control and by 10.0–23.0% relative to the treatment of plants with a zinc sulfate). At the same time, the quantitative characteristics of growth, productivity, and/or quality of the obtained products increase and improve accordingly. The prospects for further research include an in-depth study into the mechanisms of the compositions of fullerene derivatives and various compounds of trace elements’ influence on the plants, as well as the synthesis and study of the various exo- and endo derivatives of fullerenes’ properties, including C60 complex compounds with transition metals and fullerenes, which, inside their carbon networks, contain atoms of various chemical elements, such as lanthanum and others.

Relevance. The use of non-invasive photometric methods for assessing the stress states of plants makes it possible to assess the physiological state and resistance of plants.Material and methods. In small-field and vegetation experiments, we studied the photometric indicators of the physiological response of potato varieties (reflection coefficients in different ranges) to nitrogen stress created by five doses of fertilizers using contact (N-tester) and remote (N-sensor) methods.Results. Potato varieties released for the conditions of the North-Western region of the Russian Federation were studied for their ability to withstand stress provided by low and high levels of nitrogen nutrition of plants and different weights of planting tubers. The resistance of plants of different genotypes to external and internal stressors was studied by the reflection coefficients measured in 4 channels, which characterized the differences in the physiological state of plants. Ensuring the potential genotypic resistance of the organism in the form of a decrease in FIS F1,3 corresponds to the inclusion of various mechanisms of plant adaptation to external or internal influences, depending on the genotype. In the vegetative experiment, of the studied photo-optical reflection coefficients, the most informative were the FIS F1,3 indicators, which showed that the overall viability of such varieties as Peterburgsky, Charodey and Kholmogorsky turned out to be increased. The reaction type of the Kholmogorsky variety is the most promising for growing plants under stress conditions.