We studied the effect of seed treatment with salicylic acid (SA, 100 μM) on seed germination, growth, the level of lipid peroxidation (LPO), and the functioning of a number of components of the antioxidant system in wheat plants (Triticum aestivum L.) Zlata variety grown with optimal (2 μM) or excess (1500 µM) zinc content in the root environment. It has been shown that excess zinc has an inhibitory effect on root and shoot growth and also enhances the accumulation of one of the indicators of LPO development: malondialdehyde (MDA). At the same time, the structural integrity of the membranes was maintained, as indicated by the absence of changes in membrane permeability, recorded by the yield of electrolytes. The activity of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), did not change under these conditions, but the activity of guaiacol-specific peroxidase (GPO) decreased. Treatment of seeds with SA at a concentration of 100 μM, which stimulates their germination, enhanced the negative effect of excess zinc on growth performance and MDA accumulation in wheat leaves. However, in this case, the yield of electrolytes did not increase, which is presumably due to an increase in the activity of SOD and GPO. Based on the data presented in the work and previously obtained, as well as an analysis of the literature, it was concluded that the response of plants to excess zinc in the external environment, like the reaction to other abiotic stresses, is not only multicomponent and multiechelon but also variable, depending on many factors and circumstances: the dose of exposure (zinc concentration and duration of its action), biological characteristics of the plant species (variety), their age condition, etc. Treatment of seeds with SA can change the nature of the plant’s response to the action of excess zinc, and the direction of these changes will, in turn, depend on the concentration of SA, the duration of its action, and the method of treatment.

Исследовали влияние обработки семян салициловой кислотой (СК, 100 мкМ) на прорастание семян, рост, уровень перекисного окисления липидов (ПОЛ) и функционирование ряда компонентов антиоксидантной системы у растений пшеницы (Triticum aestivum L.) сорта Злата, выращиваемых при оптимальном (2 мкМ) или избыточном (1500 мкМ) содержании цинка в корнеобитаемой среде. Показано, что избыток цинка оказывает ингибирующее действие на рост корня и побега, а также усиливает накопление одного из индикаторов развития ПОЛ – малонового диальдегида (МДА). При этом структурная целостность мембран сохранялась, на что указывает отсутствие изменения проницаемости мембран, регистрируемое по выходу электролитов. Активность антиоксидантных ферментов – супероксиддисмутазы (СОД) и каталазы (КАТ) – в этих условиях не изменялась, а активность гваякол-специфичной пероксидазы (ГвПО) снижалась. Обработка семян СК в концентрации 100 мкМ, стимулирующей их прорастание, усиливала отрицательное воздействие избытка цинка в отношении показателей роста и накопления МДА в листьях пшеницы. Однако и в этом случае выход электролитов не увеличивался, что, предположительно, связано с возрастанием активности СОД и ГвПО. На основании представленных в работе и полученных ранее данных, а также анализа литературы, сделан вывод, что реакция растений на избыток цинка во внешней среде, подобно реакции на другие абиотические стрессы, является не только многокомпонентной и многоэшелонной, но и вариативной, зависящей от многих факторов и обстоятельств – дозы воздействия (концентрации цинка и продолжительности его действия), биологических особенностей вида (сорта) растений, их возрастного состояния и т.д. Обработка семян СК может изменять характер реакции растений на действие избытка цинка, при этом направленность этих изменений будет, в свою очередь, зависеть от концентрации СК, продолжительности ее действия и способа обработки.

The effect of soil contamination with lead (50 and 250 mg Pb2+ per 1 kg of dry soil weight) on the rate of photosynthetic assimilation of CO2 (An), the content of major macronutrients in leaves, photosynthetic use efficiency of nitrogen (PNUE), phosphorus (PPUE), potassium (PKUE), water (PWUE), and light (α) in lettuce plants of the variety Medvezhye Ushko was studied under controlled environmental conditions. A negative effect of the metal ion on photosynthetic rate An was revealed, which was associated with the decreases in chlorophyll content, PNUE, PPUE, PKUE, and the α value. The quantum efficiency of PSII reaction (Fv/Fm) decreased but still remained within the range typical of photosystem normal functioning. No pronounced influence of lead on the content of macronutrients in plant leaves was found. In Pb-treated plants, the decrease in PNUE, PPUE, and PKUE was accompanied by the increase in leaf mass to leaf area ratio, which reflects close structural and functional relationships during plant adaptation to stressful conditions of heavy-metal soil pollution. It was shown that lead, even in the highest concentration applied (250 mg/kg soil), affected neither the transpiration rate nor the photosynthetic water use efficiency in plants.

Wild grasses are prevalent across various types of vegetation, playing a significant role in both natural ecosystems and human economic endeavors. The potential of using grasses to restore areas affected by tidal erosion and saline soils has not been fully investigated. A study was conducted to examine the impact of different levels of NaCl salinity (ranging from 20 to 200 mM) on seed germination and early growth of Agrostis capillaris L., Deschampsia cespitosa (L.) P. Beauv., Phalaris arundinacea L., and Phleum pratense L. These plants are commonly found in the Arctic region within the Belomorsky district of the Republic of Karelia. Through research, a direct connection was discovered between the germination of seeds and the growth of seedlings based on the salt levels in the root environment and the type of grass species present. In summary, all species successfully germinated at NaCl concentrations of 20–80 mM. However, germination rates decreased at 100 and 200 mM in most cases. When exposed to NaCl concentrations of 60 mM and higher, the growth of root and shoot in the grasses was slowed down to some extent (depending on the species), but not completely inhibited. Due to the resilience of wild grasses to cold temperatures, it is proposed that they could be used in the phytoremediation of Arctic areas with a salinity level of up to 100 mM (0.6 % salinity). An analysis of the data resulted in a ranking of grass species based on their salt resistance: P. pratense ˃A. capillaris ˃P. arundinacea ˃D. cespitosa.

In a controlled environment, the effect of moderate (100 mM) and strong (200 mM) sodium chloride salinity on seed germination, seedling growth and the state of the photosynthetic apparatus (PSA) of barley (Hordeum vulgare L.) varieties Nur and wheat (Triticum aestivum L.) varieties Zlata was studied. It was found that with moderate salinization, the seeds of both species successfully germinated, but the growth of shoots and the accumulation of aboveground biomass were inhibited, which was partly due to a slowdown in the rate of photosynthesis. With strong salinity, distinct interspecific differences were observed in the response of plants. In particular, the number of germinated seeds decreased in barley, while in wheat it remained at the control level. In barley, shoot growth was inhibited to a greater extent, whereas in wheat, the accumulation of aboveground biomass was. The content of pigments in barley plants decreased, and the content of wheat increased. At the same time, stomatal conductivity decreased in both species and the rate of photosynthesis slowed down. It is concluded that based on the energy of germination and germination of seeds, it is possible to determine the salt resistance of species only to a high level of salinity (200 mM NaCl). Morphometric indicators of shoot growth make it possible to assess the resistance of plants to salinity already at lower salt concentrations (100 mM NaCl). For a more accurate comparative assessment of the salt resistance of species (varieties, varietals, genotypes) of cereals, not one, but several indicators should be used, reflecting not only the growth potential of plants, but also photosynthetic activity.

The effect of wheat seed treatment with salicylic acid (SA) on expression of the TaCu/ZnSOD, TaFeSOD, and TaCAT2 genes and activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) in leaves was studied at optimal contents of zinc (2 µM) and copper (0.3 µM) in the root environment and in zinc and copper deficiencies. Seed treatment with SA was for the first time shown to increase of the amount of transcripts of the above genes as compared with untreated plants, both in optimal conditions and in zinc or copper deficiency. Activities of the enzymes, especially catalase, also increased. Judging by the malondialdehyde (MDA) content, the changes make it possible to avoid an increase in lipid peroxidation (LPO) and, therefore, oxidative stress. A positive effect of seed treatment with SA on activities of the main antioxidant enzymes was assumed to underlie the stimulating effect of SA on physiological processes in plants exposed to microelement deficiency.

It has been shown that the studied variants of bread wheat plants are resistant to zinc deficiency in the substrate. Various ways of adaptation to these conditions by the antioxidant system have been discovered in plants that have a functional allele of the GPC-B1 gene. Thus, in plants of line 15-7-1, the maintenance of the redox balance of cells is associated with an increase in the expression of the Cu/ZnSOD gene and a decrease in the expression of the FeSOD and CAT1 genes, whereas in plants of line 13-3, in addition to an increase in the transcripts content of the Cu/ZnSOD gene, it is associated with a high constitutive activity of superoxide dismutase (SOD) and catalase (CAT). The data obtained can be used to create wheat varieties (lines) capable of producing seeds with a relatively high content of zinc under zinc deficiency in the soil.

Under the conditions of a growing experiment, the authors studied the effect of presowing treatment of seeds with salicylic acid (SA) on the growth parameters and photosynthetic apparatus (PSA) of barley plants (Hordeum vulgare L.), which are in optimal conditions of mineral nutrition or with a lack of zinc in the root environment. It has been shown that zinc deficiency does not adversely affect PSA but causes inhibition of plant growth. Presowing treatment of seeds with SA (10 μM) had a stimulating effect on the intensity of photosynthesis and stomatal conductance, which ensured successful plant growth under conditions of zinc deficiency. At the same time, in plants grown from seeds treated with SA, the content of zinc in the roots and shoots was higher than in plants whose seeds were not treated. Based on the obtained results, a conclusion was made on the possibility and prospects of using presowing seed treatment with SA for growing barley plants under conditions of zinc deficiency in the root environment.

The influence of moderate and strong chloride salinity on seedlings of barley (Hordeum vulgare L.) Nur variety was studied under controlled environment conditions. Exposure of seedlings to both moderate (100 mM) and high concentrations (200 mM) of NaCl for 7 days led to a slowdown in the growth of their roots and shoots. At the same time, in the variant using NaCl in moderate concentration, an increase in the content of pigments was noted in the leaves of seedlings (chlorophylls and carotenoids by 25 and 22%, respectively). Also the photosynthesis rate decreased by 25% (relative to the control). In contrast, under the influence of a high concentration of NaCl, the content of pigments, as well as stomatal conductance, decreased markedly, which was accompanied by an almost twofold slowdown in the rate of photosynthesis. At the same time, transpiration was inhibited and tissue hydration decreased. It was concluded that the resistance of barley to NaCl can be judged already in the early phases of plant development. It is also noted that the most sensitive to the presence of NaCl in the root environment are easily recorded morpho-physiological indicators – the linear size of the shoot and its raw biomass.

The effect of the phytohormone methyl jasmonate (MJ) on the expression of the TaGS1 and TaPCS1 genes encoding glutathione synthetase and phytochelatin synthase, respectively, which are key enzymes in the synthesis of glutathione and phytochelatins in wheat (cv. Moskovskaya 39), was studied. It was shown for the first time that pretreatment of plants by exogenous MJ (1 μM) leads to an increase in the accumulation of transcripts of the TaGS1 and TaPCS1 genes in leaves without cadmium effect. When cadmium (CdSO4, 100 μM) was added into the nutrient solution, the transcript level of the TaGS1 gene in the plants pretreated by MJ increased (compared to the untreated plants), whereas the transcript level of TaPCS1 remained unaffected. The pretreatment of plants with MJ leads to a lower accumulation of cadmium in the roots and leaves of wheat. At the same time, MJ had no effect on the linear growth parameters of plants, but had a positive effect on the accumulation of biomass under cadmium. It was assumed that MJ is involved in plant tolerance to cadmium by increasing the expression of the TaGS1 and TaPCS1 genes and, as a result, enhancing the synthesis of chelating compounds, as well as by reducing the supply of metal ions to plants.

Under the conditions of a growing experiment, the authors studied the effect of zinc at concentrations of 5 (control), 50, 100, and 150 mg/kg substrate on growth, the intensity of lipid peroxidation (LPO), and the activity of the components of the antioxidant system in Brassica juncea L. (Сzern.) variety Slavyanka and Sinapis alba L. cultivar Belgium plants. Some differences and similarities were found in the AOS response of the studied species to an excess of zinc in the root environment. Thus, there were no changes in the intensity of lipid peroxidation in B. juncea under the influence of zinc in high concentrations, despite the high content of the metal in the roots and shoots. At the same time, even in the presence of metal at a concentration of 50 mg/kg substrate, an increase in the activity of guaiacol peroxidase (GPX) and catalase was observed. In S. alba at high concentrations of zinc in the substrate, the metal content in the shoots was higher than in B. juncea. At the same time, the content of malondialdehyde noticeably increased, despite the increased activity of superoxide dismutase and GPX. In both studied plant species, an increase in the zinc concentration in the substrate to 50 mg/kg and above led to an increase in the level of proline, while the content of carotenoids decreased. Considering that, in the studied concentrations, the metal had a less strong negative effect on shoot growth in B. juncea compared with S. alba, it was concluded that plants of this species are more resistant to excess zinc in the root environment.

The effect of seed treatment with salicylic acid (SA) on the carbonic anhydrase (CA) activity, photosynthesis rate, stomatal conductance, and pigment content in wheat leaves was studied at an optimal zinc content (2 μM) and zinc excess (1500 μM). It was shown for the first time that the CA activity and stomatal conductance increased upon seed treatment with SA at the optimal zinc content as compared with untreated plants, while the photosynthesis rate was not affected. When zinc was in excess in the root zone, seed treatment with SA decreased the CA activity to a greater extent, but the photosynthesis rate was higher than in untreated plants, apparently due to an increase in the contents of chlorophylls and carotenoids and stomatal conductivity. It was concluded that SA is involved in the protective and adaptive responses of wheat plants to excess environmental zinc along with other nonhormonal factors and hormones.

We present a literature review of the significance of selenium in plants, animals, and humans. The selenium concentrations in soils with different compositions and from different regions in Russia are reported. The issue of the selenium content of plants, the main source of this element for humans, is considered. The beneficial effects of small amounts of selenium on the productivity and quality of a number of agricultural crops are noted. The possible causes of selenium deficiency in plants are indicated. A separate section examines the role of selenium in animals. Its involvement in the function of a spectrum of enzymes and proteins is demonstrated, and some animal diseases associated with deficiency of this micronutrient element are described. The impact of selenium on human health is highlighted. We address key functions of selenium in the human body, including its oncopreventive effects. The data on selenium-containing proteins are summarized, and their roles in particular biological processes are specified. The diseases caused by selenium deficiency are described in detail. Possible ideas to eliminate a deficiency of this element in humans are indicated. Lastly, we identify problems related to research on the influence of selenium on living organisms, which must be addressed in the nearest future.

In two introgressive lines of bread wheat (15-7-1 and 15-7-2), which differ in the allelic status of the Gpc-B1 gene, the expression of the gene encoding the HMA2 transport protein in flag leaves under optimum Zn content in substrate (2 µМ) and in its deficiency (0 µМ) was investigated. This is the first study to show that the plants carrying functional allele of the Gpc-В1 gene (line 15-7-1) have a higher level of TaHMA2 transcripts than the plants with nonfunctional allele of the Gpc-В1 gene (line 15-7-2) both at optimum Zn content in substrate and at its deficiency. Importantly, the high TaHMA2 gene expression did not affect the wheat shoot growth but correlated with a high Zn concentration in the aboveground part of plants. It is assumed that the NAC transcription factor encoded by the Gpc-В1 gene may be involved in the regulation of the ТаНМА2 gene expression.

Under the growth experiment, the effect of zinc deficiency in the substrate on a number of growth of barley parameters, the state of the photosynthetic apparatus (PSA), and the parameters seed productivity (Hordeum vulgare L., variety Nur) depending on the phase of plant development were studied. Differences in the response of barley to zinc deficiency at different phases of plant development were revealed. In particular, in the heading phase, the lack of this trace element in the substrate caused growth inhibition but did not adversely affect the photosynthetic function of plants. In the booting phase, the negative effect of zinc deficiency on growth parameters was smoothed out, however, inhibition of PSA activity was observed. The deterioration in the supply of inflorescences with assimilates during this period, apparently, was one of the important factors in the decrease in seed yield observed in experimental plants. In the heading phase, plants grown under conditions of zinc deficiency lagged behind the plants of the control variant in terms of shoot height and area of leaf blades of subflag and flag leaves, while the photosynthesis rate did not differ from the control values or even exceeded them. Maintaining a high rate of photosynthesis in the leaves, which are the main donors of assimilates for ripening seeds, ensured the formation of full-fledged caryopses on the main shoot, although it was in smaller numbers than under favorable conditions of mineral nutrition.

In a controlled environment, the dynamics of the activity of two key antioxidant enzymes, superoxide dismutase (SOD) and peroxidase (PO), and the expression of its encoding genes ( HvSOD1 and HvPRX07 ) were studied at the temperatures of 22 and 4°C in barley plants growing at the optimal zinc content (2 μM) in the substrate and its deficiency (0 μM). It was found that at 22°C, a zinc deficiency did not lead to an increase in the intensity of lipid peroxidation (LPO) in the barley roots and leaves, which correlates with an increase in the number of transcripts of the genes studied and an increase in the SOD and PO activity. Under hypothermia, metal deficiency caused an increase in oxidative processes in the roots of seedlings, which is associated with the absence of an increase in the activity of antioxidant enzymes, despite an increase in gene expression. At the same time, the intensification of oxidative processes did not occur in the leaves. The protection of leaf cells from oxidative stress under combined action of zinc deficiency and low temperature may be associated with an increase in the activity of other (nonenzymatic) components of the antioxidant system.

The effects of low temperature (4°C) on the rate of lipid peroxidation and activities of superoxide dismutase and peroxidase in the roots and leaves of winter wheat ( Triticum aestivum L.) plants were determined under laboratory conditions. The root medium contained the optimal (2 μM) zinc concentrations or high ones (1000 μM). It was found that, under optimal mineral nutrition, such cooling did not intensify the oxidative processes in the wheat leaves and temporarily increased them in the roots. This witnesses to the successful cold acclimation of the plants. At an excessive zinc concentration, the exposure to low temperature enhanced lipid peroxidation in both the roots and the leaves. This effect might be, to some extent, accounted for by rather weak activities of said antioxidant enzymes and incoordination of their functions in the chilled plants. In general, the revealed attenuation of the plant capacity to sustain the cellular redox balance under a joint impact of the applied stress-factors entails oxidative stress and stronger growth inhibition that, as a result, negatively affects the plants’ viability.