The use of silver nanoparticles (NPs) in medical, industrial and agricultural fields is becoming more widespread every year. This leads to an increasing number of experimental toxicological and microbiological studies of silver NPs aimed at establishing the risk–benefit ratio for their application. The following key parameters affecting the biological activity of silver dispersions are traditionally taken into consideration: mean diameter of NPs, surface potential of NPs and equilibrium concentration of Ag⁺. These characteristics are mainly predetermined by the chemical nature of the capping agent used for stabilization. However, the extent to which they influence the biological activity and the toxicity of silver NPs varies greatly. In this work, dispersions of silver NPs stabilized with a wide array of substances of different chemical nature were used for quantitative evaluation of whether the various measurable properties of silver NPs fit as descriptors of linear QNAR (quantitative nanostructure–activity relationship) models for silver NP toxicity evaluation with respect to a model eukaryotic microorganism—Saccharomyces cerevisiae yeast cells. It was shown that among the factors that determine silver NP toxicity, the charge of particles, their colloidal stability and the ability to generate Ag⁺ ions carry more importance than the descriptors related to the particle size. A significant synergistic effect between the ζ-potential and the colloidal stability of silver NPs on their toxicity was also discovered. Following this, a new descriptor has been proposed for the integral characterization of the silver dispersion colloidal stability. According to the obtained data, it can be considered applicable for building QNAR models of higher efficacy. The validity testing of the proposed model for theoretical prediction of silver NP toxicity using a wide range of living organisms has shown that this new descriptor correlates with toxicity much better compared to most traditionally used descriptors. Consequently, it seems promising in terms of being used not only in situations involving the rather narrow array of the objects tested, but also for the construction of silver NP toxicity models with respect to other living organisms.

Interest in the use of silver as a component of plant protection products and growth regulators appeared relatively recently with the development of methods for the effective stabilization of colloidal systems containing nanoparticles of this metal. In the present work, we studied the effect of foliar treatments with aqueous dispersions of silver nanoparticles stabilized by polyhexamethylene biguanide hydrochloride with an average diameter of 6 ± 1 nm and a zeta-potential of +47.4 ± 1.3 mV on legume-Rhizobium symbiosis, which largely determines the efficiency of soil nitrogen assimilation and the yield of soybean (Glycine max L. Merr.). Based on the results of a two-year field experiment, it was shown that treatments with low doses of silver nanoparticles lead to a significant increase in the number of root nodules and an increase in soybean yield. The observed biological effectiveness of silver nanoparticles dispersions is explained by an increase in the enzymatic activity of peroxidases and polyphenol oxidases in the terrestrial part of plants. It is very likely that the treatment with silver nanoparticles and the increase in peroxidase activity in non-infected parts of the plant lead to a more effective prevention of the penetration of rhizobacteria into the aboveground soybean organs, which, in turn, may be the reason for the observed decrease in the activity of peroxidase and polyphenol oxidase in parts of plant roots susceptible to rhizobia. The latter, as is known, contributes to an easier flow of the nodulation process and the development of legume–Rhizobium symbiosis.

A field trial to study the effect of preplant and foliar treatment of potatoes (lat. Solanum tuberosum) of Red Scarlett variety with dispersions of silver nanoparticles stabilized with polyhexamethylene biguanide hydrochloride was conducted. Silver nanoparticles were obtained by chemical reduction and characterized by UV–Vis spectrophotometry, transmission electron microscopy, and dynamic light scattering. The obtained nanoparticles were roughly spherical shape with the average diameter of 4.92 ± 2.66 nm. Preplant treatment of potato tubers and foliar treatment of potato plants were conducted with dispersions of silver nanoparticles with the concentrations of 5 and 0.2 mg/L, respectively. The treatment of potato with the dispersions resulted in an increase in values of morphological indicators such as stem height, tops weight and leaf weight which in turn caused a significant increase in the yield (from 10.6 to 21.9% compared to the control variant) and commercial quality of the tubers. Notably, the maximum increase in the yield was obtained with the largest number of the treatments. In addition, silver dispersions showed a phytoprotective effect on potato plants which manifested in a decrease in damage to leaves by Phytophthora infestans from 30 to 7–8%. An explanation for the observed phytoprotective effect of silver nanoparticles based on the analysis of enzymatic activity in plant leaf tissues was proposed. The obtained results demonstrate high potential of application of drugs based on silver nanoparticles in horticulture as means of stimulating of growth and protection of plants.

The problem of contamination of agricultural products with toxic substances is an urgent problem in production. One of the most chemically treated crop is vineyards. Multiple treatments during one growing season have led to the fact that grape plantings have become an accumulator of unsafe chemical plant protection products. Moreover, grapes are consumed fresh. Accordingly, the selection of environmentally friendly pesticides and the replacement of chemicals with biological ones has become a priority for producers of this crop. Our research was devoted to evaluation of bioinsecticide based on entomopathogenic bacteria B. thuringiensis in the system of protecting grapes from pests. Such studies are of great interest and, according to the literature, 90 % of registered insecticides are based on Bacillus thuringiensis . Microorganisms isolated from nature as plant protection agents, when reintroduced into natural conditions, preserve beneficial species in biocenoses. At the same time, they are selective and, while affecting certain harmful objects, do not cause harm to humans and the environment. The purpose of this work was to study the effect of the bioinsecticide Biometch Insecto, WP on grapevine pests: European grape worm ( Lobesia botrana Den. Schiff.) and leafy form of phylloxera ( Viteus vitifolii Fitch.). Biometch Insecto, WP is based on strains of Bacillus thuringiensis var. kurstaki HG207 and Beauveria bassiana HG208. The effect of entomopathogens was compared with the effect of insecticide Bioslip, BW, L, the active ingredient of which is Beauveria bassiana . The results of the research revealed high biological effectiveness (90100 %) of Biometch Insecto, WP in protecting grapevines from pests when applied during the period of mass hatching of European grape worm caterpillars and emergence of phylloxera larvae from galls.

The study investigates the use of silver nanoparticles (AgNPs) in agriculture, focusing on their potential to enhance the immune response of potato (Solanum tuberosum L.) plants against phytopathogenic attacks. The research highlights how AgNPs, stabilized by biologically active polymers polyhexamethylene biguanide and tallow amphopolycarboxyglycinate, can induce oxidative stress. Triple foliar application of 0.1–9.0 g/ha silver nanoparticles at the budding and later stages demonstrated significant efficacy in suppressing diseases caused by Phytophthora infestans and Alternaria solani (over 60%). This effect was linked to the increased activity of peroxidase—over 30–50%—and the decreased catalase activity, indicative of a well-coordinated oxidative stress response to the invasion of P. infestans and A. solani. The results suggest that AgNPs in low concentrations can prime the plant’s innate immune system, enhancing its resistance without detrimental effects on growth parameters, thus contributing to the improved crop yield. These findings underscore the potential of AgNPs not as traditional biocides, but as intelligent elicitors of plant-induced resistance, positioning them as next-generation tools for sustainable crop protection and yield optimization, which can be applied at extremely low doses (less than 10 g/ha of active substance).

The current paper is devoted to the study of melatonin as an adaptogen capable of increasing wheat tolerance to stress caused by excess levels of easily soluble salts in the environment. The purpose of the study was to evaluate, within the framework of a laboratory model experiment, the ability of melatonin to increase seed germination and stimulate growth processes in wheat sprouts against the background of salinity. The study was conduc ted at the FSBI All-Russian Scientific Research Institute of Agrochemistry named after D.N. Pryanishnikov in 2024. The study objects were seeds of the spring wheat variety ‘Darya’. Before the experiment, the seeds were treated with aqueous solutions of melatonin in concentrations of 0; 0.01; 0.1; 1 and 10 mg/l using the priming method. Distilled water and a 150 mM sodium chloride solution were used as background solutions for germination. As a result, there has been shown that within the framework of the experiment, there is an increase in seed germination against the background of treatment with melatonin solutions in concentrations from 0.1 to 10 mg/l against a saline background. Seed treatment with melatonin has demonstrated a pronounced growth-stimulating effect on wheat sprouts, especially in relation to the root system. However, the strength of this effect was somewhat reduced on a saline background compared to control conditions. There was a maximum growth-stimulating effect of melatonin on both backgrounds when using a solution with a concentration of 1 mg/l. There was also established that priming seeds with melatonin promoted water retention in seedling root cells, which may be one of the mechanisms for increasing plant resistance to salinity.