Low Molecular Antioxidants Research Articles

Peculiarities of xerophytes adaptation to drought in Chachuna managed territory and Vashlovani protected area (Eastern Georgia)

Today, when desertification is one of the expected ecological disasters in the background of global climate change, investigation of the biological mechanisms of xerophytes stress resistance has become popular. One of the key biochemical mechanisms of plant protection against unfavourable environmental conditions is a large group of compounds with different chemical nature united under the name of antioxidant system. Investigation of the characteristics of the antioxidant system of xerophytes of different habitats of the driest region of Georgia (East Georgia) was the aim of the presented study. The content of low-molecular antioxidants and osmolytes as well as the activity of antioxidant enzymes was studied in leaves of experimental plants. It has been concluded that the distinctive values of the indices of antioxidant system are manifested as the main mechanism of adaptation. There can be several such mechanisms in each species at the same time, which is probably a specific feature. In some cases, these mechanisms are similar in species of one habitat and presumably are related to the living environment; In general, it is possible to single out characteristic strategy of adaptation to stress for each studied species, which includes certain enzymatic and non-enzymatic components of the antioxidant system.

Taxonomic Diversity and Functional Traits of Soil Bacterial Communities under Radioactive Contamination: A Review.

Studies investigating the taxonomic diversity and structure of soil bacteria in areas with enhanced radioactive backgrounds have been ongoing for three decades. An analysis of data published from 1996 to 2024 reveals changes in the taxonomic structure of radioactively contaminated soils compared to the reference, showing that these changes are not exclusively dependent on contamination rates or pollutant compositions. High levels of radioactive exposure from external irradiation and a high radionuclide content lead to a decrease in the alpha diversity of soil bacterial communities, both in laboratory settings and environmental conditions. The effects of low or moderate exposure are not consistently pronounced or unidirectional. Functional differences among taxonomic groups that dominate in contaminated soil indicate a variety of adaptation strategies. Bacteria identified as multiple-stress tolerant; exhibiting tolerance to metals and antibiotics; producing antioxidant enzymes, low-molecular antioxidants, and radioprotectors; participating in redox reactions; and possessing thermophilic characteristics play a significant role. Changes in the taxonomic and functional structure, resulting from increased soil radionuclide content, are influenced by the combined effects of ionizing radiation, the chemical toxicity of radionuclides and co-contaminants, as well as the physical and chemical properties of the soil and the initial bacterial community composition. Currently, the quantification of the differential contributions of these factors based on the existing published studies presents a challenge.

Elucidation of the mechanism of elicitation of edible sprouts using UV-C radiation

The major aim of this study was to demonstrate the influence of UV-C radiation exposure of the edible sprouts on their redox status and the mechanism of production of selected phytochemicals in them. The study has shown that UV-C irradiation of broccoli sprouts and red cabbage for 5 min, and alfalfa for 15 min activates mechanisms involved in the antioxidant protection of the cell, resulting in an increase in the level of low-molecular antioxidants, i.e. polyphenols and glutathione. It was proven that sprouts irradiated with UV-C were characterised by higher MAPK expression, as well as higher level of ABA (ROS-dependent) which contributed to the induction of transcription factors (MYB) and consequently, to increased expression of proteins involved in antioxidants biosynthesis (PAL, CHS, γ-GCS, GS) and antioxidant enzymes (MnSOD, CAT). Moreover, UV-C increased mitochondrial activity, which was observed by higher concentration of ATP, as well as increased expression of SnRK1 protein.

Changes in the Antioxidant Potential of Camellia sinensis Cultures under the Influence of Phenolic Precursors.

The viability, productivity and survival of higher plants under the adverse factors influence are largely determined by the functional activity of the antioxidant system. The aim of our work was to investigate changes in formation of high-molecular (superoxide dismutase and peroxidase) and low-molecular (phenolics, including flavanols and proanthocyanidins) antioxidants in callus culture of Camellia sinensis under influence of phenolic precursors (L-phenylalanine-3 mM, trans-cinnamic acid-1 mM, naringenin-0.5 mM). According to the data obtained, the effect of precursors on tea callus cultures did not lead to significant increasing of superoxide dismutase and peroxidase activity in most cases. However, it led to the increased accumulation of the total phenolics content, as well as flavanols and proanthocyanidins contents. For C. sinensis callus cultures, the most promising regulator of phenolic compounds was L-phenylalanine, in the presence of which its content increased almost twice. Thus, the exogenous effect of various precursors is possible to use for the targeted regulation of certain phenolics classes accumulation in plant cells.

Antioxidants of Non-Enzymatic Nature: Their Function in Higher Plant Cells and the Ways of Boosting Their Biosynthesis.

Plants are exposed to a variety of abiotic and biotic stresses leading to increased formation of reactive oxygen species (ROS) in plant cells. ROS are capable of oxidizing proteins, pigments, lipids, nucleic acids, and other cell molecules, disrupting their functional activity. During the process of evolution, numerous antioxidant systems were formed in plants, including antioxidant enzymes and low molecular weight non-enzymatic antioxidants. Antioxidant systems perform neutralization of ROS and therefore prevent oxidative damage of cell components. In the present review, we focus on the biosynthesis of non-enzymatic antioxidants in higher plants cells such as ascorbic acid (vitamin C), glutathione, flavonoids, isoprenoids, carotenoids, tocopherol (vitamin E), ubiquinone, and plastoquinone. Their functioning and their reactivity with respect to individual ROS will be described. This review is also devoted to the modern genetic engineering methods, which are widely used to change the quantitative and qualitative content of the non-enzymatic antioxidants in cultivated plants. These methods allow various plant lines with given properties to be obtained in a rather short time. The most successful approaches for plant transgenesis and plant genome editing for the enhancement of biosynthesis and the content of these antioxidants are discussed.

Effect of Light of Different Spectral Compositions on Pro/Antioxidant Status, Content of Some Pigments and Secondary Metabolites and Expression of Related Genes in Scots Pine.

The aim of this study was to investigate the effect of light quality (white fluorescent light, WFL, containing UV components), red light (RL, 660 nm), blue light (BL, 450 nm), and white LED light (WL, 450 + 580 nm) on the components of the cellular antioxidant system in Pinus sylvestris L. in needles, roots, and hypocotyls, focusing on the accumulation of key secondary metabolites and the expression of related genes. The qualitative and quantitative composition of carotenoids; the content of the main photosynthetic pigments, phenolic compounds, flavonoids (catechins, proanthocyanidins, anthocyanins), ascorbate, and glutathione; the activity of the main antioxidant enzymes; the content of hydrogen peroxide; and the intensity of lipid peroxidation (MDA and 4-HNE contents) were determined. RL resulted in an increase in the content of hydrogen peroxide and 4-HNE, as well as the total fraction of flavonoids in the needles. It also enhanced the expression of several PR (pathogen-related) genes compared to BL and WL. WFL increased the content of phenols, including flavonoids, and enhanced the overall activity of low-molecular antioxidants in needles and hypocotyls. BL increased the content of ascorbate and glutathione, including reduced glutathione, in the needles and simultaneously decreased the activity of peroxidases. Thus, by modifying the light quality, it is possible to regulate the accumulation of secondary metabolites in pine roots and needles, thereby influencing their resistance to various biotic and abiotic stressors.

Survival rates and pro-oxidant-antioxidant systems of germinated Yakutian plant seeds pretreated with super-weak constant magnetic fields of different flux densities

The aim of this study was to identify physiological and biochemical changes in seedlings of wild plants of Yakutia, grown from seeds, which have received a pre-sowing, super-weak constant magnetic field treatment of different magnetic flux densities. Review of literature sources allows us to conclude that the weak effects of low-intensity fields (nonthermal character) have not been studied sufficiently so far. The study was conducted on seeds from 14 different species of wild plants native to Yakutia. The seeds were subjected to different magnetic flux strengths of 0.2–4.0 mT for 24 hours and then were germinated on filter paper. The criterion for evaluating the effect of the super-weak constant magnetic field was the formation of a true leaf in seedlings (survival rate). The intensity of lipid peroxidation processes was recorded as a pro-oxidant reaction. The total content of low molecular weight antioxidants was determined as an example of the non-enzymatic antioxidant system. The activity of an antioxidant enzyme, superoxide dismutase, was determined. The effects of the super-weak constant magnetic fields were evaluated using regression and statistical methods. Based on the working hypothesis is that the formation of the present leaf is dependent on changes in the pro-oxidant-antioxidant equilibrium in the cells of the seedlings as a result of the action on them by the super-weak constant magnetic field as a function of the magnetic flux density. We showed that the survival rate of seedlings grown from the seeds pre-treated by super-weak constant magnetic fields of different magnetic flux density for 24 hours leads to the activation of lipid peroxidation and depends on the adaptation processes of antioxidant systems (the sum of low-molecular antioxidants and superoxide dismutase activity): simple compensation or hypercompensation. In the second case, the action of super-weak constant magnetic fields leads to an increase in the survival rate of seedlings by the criterion of the formation of the true leaf. The study is of significance for specialists in magneto-biology and researchers of plant antioxidant systems.

Heavy Metals, Their Phytotoxicity, and the Role of Phenolic Antioxidants in Plant Stress Responses with Focus on Cadmium: Review.

The current state of heavy metal (HM) environmental pollution problems was considered in the review: the effects of HMs on the vital activity of plants and the functioning of their antioxidant system, including phenolic antioxidants. The latter performs an important function in the distribution and binding of metals, as well as HM detoxification in the plant organism. Much attention was focused on cadmium (Cd) ions as one of the most toxic elements for plants. The data on the accumulation of HMs, including Cd in the soil, the entry into plants, and the effect on their various physiological and biochemical processes (photosynthesis, respiration, transpiration, and water regime) were analyzed. Some aspects of HMs, including Cd, inactivation in plant tissues, and cell compartments, are considered, as well as the functioning of various metabolic pathways at the stage of the stress reaction of plant cells under the action of pollutants. The data on the effect of HMs on the antioxidant system of plants, the accumulation of low molecular weight phenolic bioantioxidants, and their role as ligand inactivators were summarized. The issues of polyphenol biosynthesis regulation under cadmium stress were considered. Understanding the physiological and biochemical role of low molecular antioxidants of phenolic nature under metal-induced stress is important in assessing the effect/aftereffect of Cd on various plant objects-the producers of these secondary metabolites are widely used for the health saving of the world's population. This review reflects the latest achievements in the field of studying the influence of HMs, including Cd, on various physiological and biochemical processes of the plant organism and enriches our knowledge about the multifunctional role of polyphenols, as one of the most common secondary metabolites, in the formation of plant resistance and adaptation.

Влияние сублимационной сушки на качественные показатели клубней картофеля

Freeze-dried vegetable production is intensively developing due to its advantages - a four-time decrease in the weight of supplied freeze-dried potatoes, increased shelf life by dozens of times, and the resistance of freeze-dried products to temperature fluctuations. To study the quality indicators of potato tubers before freeze-drying and after it using standard techniques, the authors analyzed domestic and foreign varieties including those with pigmented flesh and peel. Freeze-drying of potato tubers was carried out in the vacuum-sublimation machine USS‑5 in two stages: rapid freezing of 2 to 3 cm thick sample plates to -30°C during 4 h and heating to +50°C during 2.5 h. Raw potato tubers and freeze-dried samples were tested for antioxidant, phenolic and flavonoid content using standard methods. The results of biochemical analysis showed the total content of alcoholsoluble flavonoids in fresh potato pulp in recalculation on quercetin 0.08 to 1.13 mg/g raw weight, in freeze-dried samples - 0.22 to 1.46 mg/g dry weight; total content of low-molecular antioxidants in fresh pulp from 0.12 to 1.92 mg/g raw weight, phenolic compounds in freeze-dried samples from 0.55 to 4.63 mg/g dry weight in gallic acid equivalents. The study also focused on the determination of the moisture absorption level of freeze-dried potato tuber slices. Moisture saturation of freeze-dried potato slices when immersed in room temperature water occurred within 60 min. Freeze drying had no effect on the antioxidant content of the potato tubers. Therefore, this method can be used to produce healthy foods.

Activity of low-molecular weight components of Larix sibirica antioxidant system under exposure to technogenic pollution.

Changes in the antioxidant protection system of Larix sibirica Ledeb at different pollution levels caused by emissions from a large aluminum smelter (BrAS) have been studied. We revealed that the content of peroxide (H2O2) in the needles is a reliable marker of oxidative stress in the trees under pollution. The crucial role of non-enzymatic components, in particular, proline, phenolic compounds, ascorbic acid, glutathione, in reducing the level of free radicals in the needles cells was found. Proline concentration in the needles significantly rises with the increase in pollution levels from low to high. Under critical level pollution, it decreases by 40% compared to the background. The total content of ascorbic acid (ASC) in the needles of polluted trees varies slightly; however, there are significant changes in its various forms. With an increase in pollution to a high level, the content of the reduced form of ASC in the needles increases by 1.5-2.9 times compared to the background content. At a critical level of pollution, the total level of ascorbic acid and its reduced form falls, the content of the oxidized form reaches minimum values. The total content of phenolic compounds in the needles increased by 50-55%, concentration of flavonoids by 1.5-1.8 times, catechins by 1.9-2.5 times, proanthocyanidins by 45% compared to the background level under low, moderate, high pollution, whereas under critical pollution their content decreased. The absolute concentration of the reduced form glutathione in the needles falls by 1.9-3.0 times, the oxidized form increases by 1.5-2.0 times compared to the background. The ratio of reduced glutathione to oxidized glutathione decreased, especially during critical pollution. The data obtained show significant activation of Siberian larch biochemical protection at low, moderate and high levels of pollution by the aluminum smelter emissions. At a critical levels of contamination, a significant depletion of the pool of low-molecular antioxidants was observed.

Multiomics Analyses of Two Sorghum Cultivars Reveal the Molecular Mechanism of Salt Tolerance.

Sorghum [Sorghum bicolor (L.) Moench] is one of the most important cereal crops and contains many health-promoting substances. Sorghum has high tolerance to abiotic stress and contains a variety of flavonoids compounds. Flavonoids are produced by the phenylpropanoid pathway and performed a wide range of functions in plants resistance to biotic and abiotic stress. A multiomics analysis of two sorghum cultivars (HN and GZ) under different salt treatments time (0, 24, 48, and 72) was performed. A total of 45 genes, 58 secondary metabolites, and 246 proteins were recognized with significant differential abundances in different comparison models. The common differentially expressed genes (DEGs) were allocated to the “flavonoid biosynthesis” and “phenylpropanoid biosynthesis” pathways. The most enriched pathways of the common differentially accumulating metabolites (DAMs) were “flavonoid biosynthesis,” followed by “phenylpropanoid biosynthesis” and “arginine and proline metabolism.” The common differentially expressed proteins (DEPs) were mainly distributed in “phenylpropanoid biosynthesis,” “biosynthesis of cofactors,” and “RNA transport.” Furthermore, considerable differences were observed in the accumulation of low molecular weight nonenzymatic antioxidants and the activity of antioxidant enzymes. Collectively, the results of our study support the idea that flavonoid biological pathways may play an important physiological role in the ability of sorghum to withstand salt stress.

Antioxidative and osmoprotecting mechanisms in carrot plants tolerant to soil salinity

Soil salinization is a growing problem for agriculture worldwide and carrot is one the most salt-sensitive vegetable species. However, some varieties are capable of withstanding high salt concentrations due to unknown genetic and physiological mechanisms. The aim of this work was to reveal protecting mechanisms against osmotic and ionic stresses that contribute to salt tolerance in carrot. For this purpose, changes in biochemical traits due to soil salinity occurring in the salt-tolerant and salt-sensitive plants were determined. The obtained results showed that the tolerance of the salt-tolerant variety was partially determined constitutively, however, the exposition to saline soil triggered a physiological response that was more evident in the root than in the leaves. The most noticeable changes were the high increase in the content of osmoprotective proline and other low molecular antioxidants such as glutathione and ascorbic acid, and the decrease in the ratio of reduced to oxidized glutathione forms. These changes imply an efficient operation of the ascorbate–glutathione cycle that together with a high activity of antioxidative enzymes such as peroxidases, indicate on the induction of mechanisms associated mainly with protection against excessive reactive oxygen species.

Antioxidant Content and Antioxidant Capacity of the Protein-Rich Powdered Beverages Enriched with Flax Seeds Gum.

Powdered beverages produced from dried fruit and vegetables are new products whose properties may be tailored by adding efficient nutrients and functional ingredients. The analyses of low-molecular antioxidants and antioxidant properties as well as nutrient content and digestibility were tested in beverages enriched with lentil proteins (AGF) and flaxseed gum (FSG). A replacement of sprouted lentil flour with the AGF deteriorated the phenolic content. As a main source of phenolics and vitamin C, lyophilized parsley leaves and broccoli sprouts were recognized. (There was no clear effect of the FGS.) The highest content of phenolics was determined in the beverages with these additives without the AGS (c.a. 125 μg/g). The AGF significantly improved the ability to quench ABTS radicals and reduce power. The best results were for the beverages without the FSG. (The effect was enhanced by lyophilized fruit and green vegetables.) The lowest chelating power and ability to quench hydroxyl radicals were in the beverages based on the AGF (improvement by the FSG and green vegetables). The tailoring of beverages’ recipes significantly increased protein content and did not affect nutrient digestibility. The modifications allow obtaining the beverages exhibiting multidirectional antioxidant properties, being a source of easily bioaccessible starch and proteins.

Integrative Biomarker Indices in a Benthic Indicator Species Modiolus Modiolus (L.) Under a Simulated Oil Spill

The horse mussel Modiolus modiolus (L.) is a sentinel bivalve species used in monitoring programs to assess potential biological exposure to anthropogenic contaminants, including oil hydrocarbons, in benthic environments. In an aquarium based experiment, these mussels were exposed to a simulated oil spill where crude oil at realistic concentrations (from low to high) interacted with an inert environment (seawater, gravel surface, etc.) and the biota. Using a combination of endpoints that included tissue contaminant load, protease activity, antioxidant enzyme activity, and low-molecular antioxidant profiles, we characterized M. modiolus responses to this simulated crude oil spill. Significant differences were observed in tissue protein reserves, protease activity, and oxidative stress markers including glutathione content and glutathione-S-transferase activity in the hepatopancreas and gill tissues of the bivalves treated with oil. Total concentrations of oil-derived polycyclic aromatic hydrocarbons in M. modiolus tissues were generally highest under the highest ambient oil concentration with much lower levels at the lowest. This general pattern does match the activity of protein quality control proteases but not the antioxidant enzyme activity profiles. Glutathione-S-transferase activity in bivalves showed decreased activity under the high compared to the lower oil load and oil-free animals, while glutathione content and calpain activity were positively correlated with oil uptake. The data suggest that these benthic organisms were exhibiting biological responses to the oil polycyclic aromatic hydrocarbons and support the bioindicator value of the species.
 Keywords: M. modiolus, oil spill, PAHs, integrative biomarker approach, protein quality control, GSH, GST

Antioxidants as a defence against reactive oxygen species

Reactive oxygen species are formed as a natural product of metabolic processes occurring in the organism or under the influence of external factors. Under homeostasis, they play an important role as a cellular signaling device. During oxidative stress, when they are produced in excess, they can cause damages to proteins, lipids, carbohydrates or nucleic acids. Exposure of cells and extracellular structures to free radicals activate natural mechanisms to eliminate free radicals and their derivatives. The aim of the article was to present what antioxidants are, and how they protect cells against the free radicals. The protective system against the free radicals consists of antioxidant enzymes: superoxide dismutase, catalase, glutathione peroxidases, and reductase. Low-molecular antioxidants such as vitamin C, E, carotenoids, coenzyme Q10, flavonoids, glutathione and melatonin also play an important role.

Glutathione: Role in Oxidative/Nitrosative Stress, Antioxidant Defense, and Treatments

AbstractGlutathione (GSH) is the most abundant cellular tripeptide (L‐γ‐glutamate‐L‐cysteinyl‐glycine) which is as critical as oxygen and water. This low molecular mass antioxidant has a very high intracellular concentration that ranges from 1–10 mM and reaches extreme concentration points in malignant cell types. This defender of the cell is compartmentalized in mitochondria, nucleus, peroxisomes, endoplasmic reticulum (ER), and cytosol where it is synthesized. The enzymes involved in GSH redox cycling are important for both cellular free radical and non‐radical detoxification. The present review article is covering the crucial roles of GSH to combat oxidative/nitrosative stress related to different diseases/disorders and possible drug designing for new therapies.

Marine and freshwater microalgae as a sustainable source of cosmeceuticals

A prominent feature of stress-tolerant microalgae is their versatile metabolism, allowing them to synthesize a broad spectrum of molecules. In microalgae, they increase stress resilience of these organisms. In human body, they exhibit anti-aging, anti-inflammatory, and sunscreen activities. This is not surprising, given that many of the stress-induced deleterious processes in human body and in photosynthetic cell are mediated by the same mechanisms: free-radical attacks and lipid peroxidation. It is also worth noting, that the photosynthetic machinery of microalgae is always at risk of oxidative damage since high redox potentials and reactive molecules are constantly generated during its functioning. These risks are kept at bay by efficient reactive oxygen species elimination systems including, inter alia, potent low-molecular antioxidants. Therefore, photosynthetic organisms are a rich source of bioactive substances with a great potential for curbing the negative effects of stresses, acting on human skin cells on a day-to-day basis. In many cases these compounds appear to be less toxic, less allergenic, and, in general, more “biocompatible” than most of their synthetic counterparts. The same algal metabolites are recognized as promising ingredients for innovative cosmetics and cosmeceutical formulations. Ever increasing efforts are being put into the search for new natural biologically active substances from microalgae. This trend is also fueled by the growing demand for natural raw materials for foods, nutraceuticals, pharmaceuticals, and cosmetology, associated with the global transition to a “greener” lifestyle. Although a dramatic diversity of cosmeceuticals was discovered in macrophyte algae, single-celled algae are on the same level or even surpass them in this regard. At the same time, a large-scale biotechnological production of microalgal biomass, enriched with the cosmeceutical compounds, is more technically feasible and economically viable than that of macrophyte biomass. The autotrophic cultivation of microalgae is generally simpler and often cheaper than that of heterotrophic microorganisms. Cultivation in bioreactors makes it possible to obtain more standardized raw biomass, quality of which is less dependent on seasonal factors. Microalgae biotechnology opens many possibilities to the “green” cosmeceutical production. However, a significant part of microalgae chemo- and biodiversity remains so far untapped. Consequently, bioprospecting and biochemical characterization of new algal species and strains, especially those isolated from habitats with harsh environmental conditions, is a major avenue for further research and development. Equally important is the development of approaches to cost-effective microalgae cultivation, as well as induction, extraction, and purification of cosmeceutical metabolites. World scientific community is rapidly accumulating extensive information on the chemistry and diverse effects of microalgae substances and metabolites; many substances of microalgal origin are extensively used in the cosmetic industry. However, the list of extracts and individual chemicals, isolated from them and thoroughly tested for safety and effectiveness, is not yet very large. Although excellent reviews of individual microalgal cosmeceutical groups exist, here we covered all the most important classes of such compounds of cosmeceutical relevance, linking the patterns of their composition and accumulation with the relevant aspects of microalgae biology.

Effect of Crude Oil on Growth, Oxidative Stress and Response of Antioxidative System of Two Rye (Secale cereale L.) Varieties.

Rye (Secale cereale L.) is one of the most important cereal crops in Eastern and Northern Europe, showing better tolerance to environmental stress factors compared to wheat and triticale. Plant response to the crude oil-polluted soil depends on plant species, oil concentration, time of exposure, etc. The current study is aimed at investigating the growth, oxidative stress and the response of antioxidative system of two rye varieties (Krona and Valdai) cultivated on crude oil-contaminated soils at different concentrations (1.5, 3.0, 6.0, and 12.0%). Inhibition of rye growth was observed at crude oil concentrations of above 3% for above-ground plant parts and of above 1.5% for roots. A decrease in content of chlorophyll a and total chlorophylls in Krona variety was detected at 1.5% oil concentration in soil and in Valdai variety at 3% oil concentration. Compared with the control, the content of malondialdehyde was significantly increased in the Krona variety at 3% oil concentration and in Valdai variety at 6% oil concentration. The crude oil-induced oxidative stress was minimized in rye plants by the enhanced contents of low-molecular antioxidants (proline, non-protein thiols, ascorbic acid, phenolic compounds) and activities of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione peroxidase. The strongest positive correlation was detected between the content of malondialdehyde and contents of proline (r = 0.89–0.95, p ≤ 0.05) and phenolic compounds (r = 0.90–0.94, p ≤ 0.05) as well as superoxide dismutase activity (r = 0.81–0.90, p ≤ 0.05). Based on the results of a comprehensive analysis of growth and biochemical parameters and of the cluster analysis, Valdai variety proved to be more resistant to oil pollution. Due to this, Valdai variety is considered to be a promising rye variety for cultivation on moderately oil-polluted soils in order to decontaminate them. At the same time, it is necessary to conduct further studies aimed at investigating oil transformation processes in the soil-rye system, which would make it possible to determine the efficiency of using this cereal for soil remediation.

Antioxidant status of barley seedlings under conditions of excess manganese

The system of protection against the effects of heavy metals (TM) can differ not only in different species of plants, but also in different varieties. Manganese (Mn), as a biogenic element, is necessary for normal plant growth and development. However, in the case of concentrations exceeding the optimal level, it negatively affects both linear plant growth and physiological processes. The paper presents data on the assessment of the effect of excess manganese (II) ions (30, 60 and 90 mg/l of active substance) on barley seedlings of different varieties. Resistance of plants to ionic toxicity of manganese (II) was judged by the value of antioxidant activity (AOA) of superoxide dismutase (SOD), the content of low-molecular antioxidants (chlorophyll a and b, carotenoids and anthocyanins) in barley leaves. For most of the varieties studied, an increase in AOA of SOD, the content of anthocyanins indicating the activation of plant protective mechanisms, was noted. The amount of green pigments, as well as carotenoids, on the contrary, decreased, compared with the control, which indicated a violation of the processes of photosynthesis in them.

Regulation of the Phenolic Compounds Accumulation in the Tea-Plant Callus Culture with a Separate and Combined Effect of Light and Cadmium Ions

The effect of light and cadmium ions (Cd) on the morphophysiological characteristics and accumulation of low molecular weight phenolic antioxidants in the tea plant Camellia sinensis L. callus culture under their separate and combined action is studied. It was established that the light exposure and the cadmium intake separately led to a change in the morphophysiological characteristics of the culture, a decrease in its growth, and activation of the antioxidant system. It was noted that it was manifested in an increase in the total content of phenolic compounds, flavans, and proanthocyanidins (to a lesser extent) and did not depend on the activity of the phenolic metabolism key enzyme, L-phenylalanine ammoniac lyase. It was found that the cell response was more pronounced under the action of Cd than under the action of light. In some cases, these indicators correlated with the level of lipid peroxidation in callus cultures. It is shown that all changes were more pronounced under the combined action of light and Cd.