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.

An analysis of literary data on the intake of cadmium in Poaceae plants and its accumulation in the under- and aboveground organs of these plants was performed. Information about modern concepts of ca

The effect of methyl jasmonate (MJ) (1 µM) on wheat (Triticum aestivum L. cv. Moskovskaya 39), seedlings and the fatty acid (FA) content of leaves under optimal and cadmium (Cd) (100 µM) stress conditions wasinvestigated. Height and biomass accumulation was studied traditionally; the netphotosynthesis rate (P_n) was studied using a photosynthesis system, FAs’profile—GS-MS. No effect on the height and P_n rate of the MJ pre-treatment wheat at optimum growth conditions was found. MJ pre-treatment led to a decrease in the total amount of saturated (about 11%) and unsaturated (about 17%) identified FAs, except α-linoleic FA (ALA), which is probably associated with its involvement in energy-dependent processes. Under Cd impact, the MJ-treated plants had a higher biomass accumulation and P_n rate compared to untreated seedlings. Both MJ and Cd caused stress-induced elevation of palmitic acid (PA) versus an absence of myristic acid (MA), which is used for elongation. It is suggested that PA participates in alternative adaptation mechanisms (not only as a constituent of the lipid bilayer of biomembrane) of plants under stress. Overall, the dynamics of FAs showed an increase in the saturated FA that is important in the packing of the biomembrane. It is supposed that the positive effect of MJ is associated with lower Cd content in plants and a higher ALA content in leaves.

Zinc (Zn) is a fundamental micronutrient for plants’ metabolism, but in high concentrations, it is toxic. In this study, we investigated the physiological response of white mustard (Sinapis alba L. cv. Belgia) plants to the Zn excess concentrations (50, 100, and 150 mg kg⁻¹) in the substrate. The results showed that sand Zn concentration of 50 mg kg⁻¹ did not affect the physiological parameters of plants, despite to the high Zn accumulation in shoots. The growth, biomass accumulation, photosynthesis rate, and pigment amount were inhibited at Zn concentrations of 100 and 150 mg kg⁻¹ in substrate. A slight increase in malondialdehyde (MDA) was also observed at zinc concentrations (100 and 150 mg kg⁻¹) without changes in membrane permeability, which is partly connectedtoan increase in the proline content. The results suggested that white mustard tolerates Zn excess impact. S. alba is able to grow on Zn-contaminated substrates along with significant Zn accumulation in shoots, which supports its high potential for phytoremediation of Zn-polluted agricultural soils. It is also possible to propose the following recycling of white mustard plants for Zn fortification feedstuff.

It was shown that cadmium causes a slowdown of green foxtail Setaria veridis (L.) Beauv. shoots; however it had no effect on root growth or accumulation of underground and above-ground biomass. In the analysis of the effect of cadmium on the water regime and photosynthesis of plants, it was found that it had a negative effect on the stomatal apparatus, which led to a decrease in the transpiration rate and stomatal conductance. It was noted that the water content of tissues, as well as the rate of photosynthesis in the presence of cadmium, remained at the level of those in control plants. A high resistance of green foxtail to the effects of cadmium was established, which is provided with different adaptive mechanisms and anatomical and physiological characteristics associated with its affiliation to the group of C₄-plants.

The content of transcripts of HvHMA2 and HvHMA3 genes in roots and leaves of 3-day-old (the stage of seed germination) and 7-day-old (the seedling stage) barley (Hordeum vulgare L., cv. Zazerskii 85) seedlings in the presence of cadmium ions (100 μM) was studied. Some organ-specific and age-related differences in the level of mRNAs of studied genes were identified. So, after a 4-day exposure of plants to a solution containing cadmium ions, the level of transcripts of HvHMA3 gene increased in the roots of 3-day-old seedlings, contributing to the sequestration of toxic ions in the vacuole. The level of HvHMA2 transcripts increased stronger in 7-day-old seedlings, especially in the leaves, which apparently may lead to an increased inflow of the metal ions in the phloem and to an activation of its translocation from the leaves to the roots. The observed decrease in this gene transcripts in the roots contributed in its turn to a limitation of cadmium transport to the shoots. A conclusion about the possible involvement of HvHMA2 gene in an increase of resistance of 7-day-old barley plants to cadmium was drawn based on the comparison of gene transcripts and the resistance of seedlings of different ages to this metal.