1, 2, 4-triazole derivatives, including tebuconazole, have been reported to show positive physiological effects in cereals apart from fungicidal activity and to increase plants’ tolerance against temperature stress. This study investigates the mechanisms of increasing frost resistance of etiolated winter wheat (Triticum aestivum L., “Irkutskaya” variety) seedlings by tebuconazole-based seed dresser “Bunker” (1.5 μL g⁻¹ of seeds) and tebuconazole (30 μg g⁻¹ of seeds). To identify ABA-dependent and ABA-independent pathways of frost resistance, we used fluridone (FLD, 5 mg L⁻¹), an inhibitor of endogenous abscisic acid (ABA) synthesis. FLD effectively inhibited the accumulation of carotenoids in the shoots and prevented the formation of carotenoids caused by the “Bunker” and tebuconazole. In non-hardened seedlings, FLD stimulated coleoptile and first leaf growth, but did not suppress the growth inhibitory effects of “Bunker” and tebuconazole. In shoots of hardened seedlings, FLD reduced the retarding effect of tebuconazole. Regardless of seedling age, temperature, and the protectant treatment, FLD had no effect on the sugar content in the shoots. FLD did not essentially influence frost resistance induced by “Bunker” and tebuconazole in cold-hardened seedlings. Fluridone increased H₂O₂ content and guaiacol peroxidase activity under control conditions (both with tebuconazole and without tebuconazole) and during cold hardening (in seedlings from seeds treated with tebuconazole). ABA levels in cold-hardened seedlings treated with FLD alone, tebuconazole alone, or a combination of the two were two to three times lower than in untreated hardened seedlings. Changes in indole-3-acetic and salicylic acids in response to FLD and tebuconazole treatment indicate complex interactions with signaling cellular systems. Our results suggest that tebuconazole activates ABA-independent pathways more strongly than ABA-dependent pathways in enhancing frost resistance. The potential mechanisms of tebuconazole action in plant cells are discussed.

Synthetic auxins are used in agriculture as herbicides worldwide, which leads to localized pollution and their potential entry into food crops during early developmental stages. Triticum aestivum L. is a major agricultural crop, and for this reason, understanding the mechanisms by which herbicides affect photosynthetic and lipid metabolic processes in wheat is crucial for assessing yield reduction risks. This study aimed to evaluate the toxic effects of three synthetic auxins, 1-naphthaleneacetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D), and clopyralid (CLD) on growth parameters, membrane permeability, lipid peroxidation (LPO) product content, fatty acid (FA) profiles, and photosynthetic pigment levels in both etiolated and green spring wheat seedlings. FA content was assessed using gas chromatography-mass spectrometry. The results revealed that NAA and 2,4-D exerted the most pronounced inhibitory effects on seedling growth, whereas 2,4-D and CLD increased membrane permeability. In etiolated seedlings exposed to synthetic auxins, there was an elevation in FA content noted. Conversely, in green seedlings, exposure to all tested synthetic auxins led to a reduction in FA content, particularly affecting polyunsaturated fatty acids (PUFAs), as well as declines in chlorophyll and carotenoid levels. CLD reduced odd-chain fatty acid content (OCFAs) and very long-chain fatty acid content (VLCFAs) to undetectable levels. The increase in LPO products under the action of 2,4-D and CLD indicates oxidative stress as a possible cause of the decrease in PUFA content in green seedlings. These findings suggest that synthetic auxins have detrimental impacts on the photosynthetic apparatus of wheat, which in turn may have negative consequences for its productivity.

Copper is an essential trace element for plant organisms, but in high concentrations it can be toxic to plants. Copper nanoparticles (NPs) are less toxic, and their use in plant treatment appears to be safer, more effective, and more economical than copper salts. The mini-review provides basic information about the mechanisms of action of copper-containing NPs on the plant organism and provides examples of research in this area. The main directions of influence of copper-containing NPs on plants are the processes of growth and development of the plant organism (organogenesis, mitosis, biomass accumulation), biochemical processes (the intensity of photosynthesis, antioxidant status and the intensity of lipid peroxidation processes), the effect on gene expression in the cell, the effect on plant resistance abiotic and biotic stress factors. The promise of using copper NPs as mineral fertilizers has been shown by stimulating seed germination, plant growth and development, and increasing plant resistance to stress factors under the influence of copper NPs. The protective effect of copper-containing NPs is often explained by their antioxidant activity. At the same time, there are a number of studies demonstrating the negative impact of copper-containing NPs on the growth and development of plants and the intensity of photosynthesis. The second part of the article is devoted to a description of the mechanisms of antimicrobial activity of copper-containing NPs. The antibacterial effect of copper-containing NPs is associated with the attachment of copper NPs to the surface of the bacterial cell with subsequent disruption of the membrane potential, which further leads to the development of oxidative stress and damage to vital biomolecules. Copper-containing NPs have a pronounced antibacterial effect against bacterial phytopathogens of cultivated plants Ralstonia solanacearum, Xanthomonas axonopodis, Erwinia amylovora, as well as against a number of bacteria pathogenic to humans and animals. Thus, copper NPs are promising agents for agriculture, but their effect on plants requires careful selection of optimal concentrations and comprehensive studies to avoid toxic effects.

Рассмотрены сферы применения наночастиц (НЧ) серебра в сельском хозяйстве. Приведен обзор литературы, посвященной использованию соединений НЧ серебра в животноводстве при кормлении и лечении сельскохозяйственных животных. Рассмотрены основные направления внедрения наносеребра в практику при защите культурных растений и их возделывании. Авторы представляют свои основные результаты исследований в этой области. Препарат “Арговит”, созданный на основе НЧ серебра и поливинилпирролидона, снижает антибиотикочувствительность, адгезивную и антилизоцимную активности патогенов родов Enterococcus, Salmonella и Escherichia, которые определяют возникновение, развитие и проявление инфекционных болезней у животных. Обнаружено, что нанокомпозиты серебра, представляющие собой НЧ серебра, погруженные в матрицы из природного полисахарида (арабиногалактана) или гуминовых веществ, обладают антибактериальным эффектом к бактерии, вызывающей кольцевую гниль картофеля. При этом нанокомпозиты оказывают стимулирующее воздействие на растения картофеля in vitro. Представленные сведения подтверждают перспективность широкого применения НЧ серебра в сельском хозяйстве.

A summary of data on the antibacterial effect of nanocomposites (NCs) against the phytopathogenic bacterium Clavibacter sepedonicus (Cms) is presented. The NCs are obtained by chemical synthesis by immersing nanoparticles (NPs) in a natural polymer matrix. Both chalcogens: selenium and sulfur, and metal NPs: silver and manganese are used as NPs in the NCs. The natural polymer matrix for the NCs is polysaccharides: arabinogalactan (AG), starch, carrageenan, and polymers of a different nature, humic substances: therapeutic mud, coal, and shale obtained from various sources in Mongolia. In our studies, Se/AG NC has the most pronounced antibacterial activity against Cms. This NC has a pronounced bactericidal effect, reduces the growth of the bacterial suspension by increasing the number of dead cells in it, and has an antibiofilm effect. Studies using microscopy methods show that Se NPs attach to the surface of Cms causing cell deformation and its further destruction. The causes of such events could be changes in the fatty-acid composition of the bacterial cell under the influence of the NC, as well as deterioration in the functioning of dehydrogenases. NCs based on S NPs and Ag NPs do not have all the desired properties; they either reduce biofilm formation or have antimicrobial activity. The manganese-containing NCs have a pronounced biological effect against Cms only at increased concentrations. Thus, the data presented in this work allow us to consider NCs, especially Se/AG NCs, as an effective alternative to pesticides for regulating the number of phytopathogenic bacteria.

Strobilurin and triazole class fungicides are actively used in agriculture as part of dressers to protect plants from fungal disease. In addition, they have various physiological effects on plants, including increased resistance to adverse environmental factors. The combined effect of these fungicides under water stress is understudied. The present work aims to examine the individual and combined effects of tebuconazole and azoxystrobin on the growth characteristics of wheat and its resistance to water stress. The study used winter wheat (Triticum aestivum L. ) plants grown from seeds treated with tebuconazole (2 mg/50 g seeds) and azoxystrobin (4 mg/50 g seeds) suspensions separately or together. In order to create water stress, five-day seedlings were transferred to 20% polyethylene glycol solution (PEG 6000), with stability assessed at seven and nine days. Tebuconazole was found to have a retardant effect on shoots and stimulate root growth. Azoxystrobin inhibited shoot growth and particularly root growth. When used together, tebuconazole partially reduced azoxystrobin-induced root inhibition. Azoxystrobin increased the negative effect of water stress, while tebuconazole effectively protected the root system of seedlings, partially reducing the effect of azoxystrobin. The stimulation of root growth with tebuconazolewas concluded to play an important role in providing resistance of winter wheat to water stress and to have the potential for use in agriculture.