Biofortification of garlic and onion plants with selenium and arbuscular mycorrhizal fungi inoculation are considered beneficial for producing functional food with anticarcinogenic properties. The effects of arbuscular mycorrhizal fungi (AMF) inoculation, sodium selenate foliar application, and the combination AMF + selenium (Se), compared to an untreated control, were assessed regarding the bulb yield, biochemical characteristics, and mineral composition. AMF + Se application resulted in the highest yield, monosaccharides, and Se content in both garlic and onion bulbs; and an increase of ascorbic acid and flavonoids in onion, and flavonoids in garlic. The highest bulb concentrations of P and K were recorded under the AMF + Se application, Ca was best affected by AMF, and Mg accumulation was highest under all the treatments in garlic and upon AMF + Se application in onion bulbs. Contrary to garlic, onion bulbs were characterized by a remarkable increase in microelements (B, Cu, Fe, Mn, Si, Zn) under the AMF + Se treatment. Selenium, either with or without AMF application, promoted the accumulation of B and Si in onion and Mo and Zn in garlic bulbs. It can be inferred that the interaction between AMF and Se is highly specific, differing for garlic and onion grown in similar environmental conditions in Grozny region, Chechen Republic.

The importance of using the barks of trees and shrubs as powerful natural antioxidants suggests the necessity to evaluate the effect of different environmental factors on bark extracts’ quality. The determination of total antioxidant activity (AOA) and polyphenol content (TP) in the bark of 58 tree and shrub species from 7 regions differing in mean annual temperature, insolation, humidity, salinity level, and altitude was performed. The above stress factors positively affected bark AOA but did not have a statistically significant effect on TP. The bark of trees grown in the seashore proximity was characterized by significantly higher AOA than samples gathered in other areas, similarly to the trees grown at high altitude. The bark antioxidant status of 18 species was described for the first time. New sources of powerful antioxidants were represented by the ornamental shrubs Cornus sanguinea and Cornus alba, which showed the highest AOA (169–171 mg GAE g⁻¹ d.w.). Among the typical halophytes, Calligonum and Tamarix had high AOA (172 and 85 mg GAE g⁻¹ d.w.), while in the bark of tamarisk, an Se accumulator, an Se concentration of about 900 µg kg⁻¹ d.w. was recorded. A significant positive correlation was found between leaves and bark AOA in the Karadag Nature Reserve’s deciduous trees (r = 0.898, p < 0.01). The relationship between bark AOA and TP was highly significant (r = 0.809; p < 0.001) for all samples except the mountainous ones. The results of the present research revealed new opportunities in successive bark utilization.

Allium species have great potential in the production of functional food via selenium biofortification. This review is devoted to the specificity of Allium plant biofortification with Se, including the genetic peculiarities, effect of the chemical form of the microelement, methods of supply, sulfur and AMF effects, and hormonal regulation. The biosynthesis of methylated Se amino acids and the beneficial effect of Se treatment on secondary metabolite accumulation and plant yield are discussed. Special attention is paid to the production of functional foods based on Allium plants enriched in different ways: bread with leek leaf powder, Allium microgreens and seedlings, and ‘Black garlic’ biofortified with Se. Further focus is provided to the high variability of Allium crop yield and quality under Se supply governed by genetic factors and environmental stresses, and to the need for plant growth technology optimization to obtain the predicted nutritional characteristics of the derived functional product with high anti-carcinogenic activity.

Despite the high value of ramson (Allium ursinum) in medicine and nutrition, it is not cultivated in open fields due to the need for shading as well as weeding during the early crop stages. Research was carried out in an open field with the aim to improve A. ursinum growth, through its intercropping with Armoracia rusticana (horseradish). In the latter context, with and without sodium selenate application, ramson and horseradish showed reciprocal growth stimulation, as ramson biomass increased by 1.28 times and horseradish root biomass by 1.7 times. The biofortification level of horseradish roots increased from 5.9 to 9.6 times due to joint plant growth under selenium (Se) supply. The opposite phenomenon was recorded for ramson leaves, as the biofortification level decreased from 11.7 in the case of Se supplementation to 6.7 in plants supplied with sodium selenate when jointly cultivated with horseradish. Among the tested antioxidants, the highest increase due to joint cultivation and/or Se supply was recorded for ascorbic acid by 1.69 times in ramson leaves and 1.48 and 1.37 times in horseradish roots and leaves, respectively. All treatments significantly increased the total antioxidant activity (AOA) of horseradish leaves (by 1.33–1.49 times) but not roots. Comparison of the results obtained in field conditions with those obtained earlier for the Se biofortification of ramson in the natural habitat (forest) revealed significantly higher levels of the plant’s antioxidant status under environmental stress (field) and a decrease in the correspondent differences as a consequence of Se biofortification. The estimation of allelopathic beneficial interaction between ramson and horseradish implies the efficiency of ramson growth and production of functional food with high levels of Se (Se–ramson leaves and Se–horseradish roots).

The high biological activity of cultivated and wild purslane offers broad possibilities for utilizing this plant in medicine and human nutrition. To assess the prospects of obtaining new functional food products based on the wild form of P. oleracea L., foliar biofortification of this species with sodium selenate (VI) was carried out, and the changes in leaf and seed biochemical characteristics were investigated. Selenium significantly enhanced plant yield, photosynthetic pigments and the ascorbic acid content, and showed a tendency to seed productivity increase. The application of selenium augmented quinic acid content in leaves by 1.7 times but did not affect the oxalic acid content. Oxalic acid prevailed in wild purslane and quinic acid in cultivated purslane (cv. Makovey). Seed oil in Se-enriched purslane was characterized by a two-fold decrease in saturated fatty acids and squalene and 2.3-fold decrease in malonic dialdehyde content, along with a 1.4-fold increase in ascorbic acid. Selenium supplementation resulted in an increase in total lipids and mono- and di-unsaturated fatty acids and did not affect the concentration of ω-3 fatty acids and sterol accumulation. Among the identified sterols, only the minor ones (fucosterol, 7-stigmasterol and ∆7-avenosterol) showed a slight decrease upon Se supply. Compared to seeds of cv. Makovey, wild purslane seeds had higher levels of antioxidant activity by a factor of 2 and of polyphenols by a factor of 3.2 but did not differ significantly in oil fatty acid composition. The results indicate the importance of wild purslane leaves/seeds both fortified and not fortified with Se in human nutrition and medicine.

The mineral composition of edible plants often changes as a result of selenium biofortification, which affects plant species tolerance and adaptability to Se supply, as well as nutritional value. To reveal the peculiarities of macro- and microelements in root–leaf–seed distribution in wild purslane foliar treated with sodium selenate (50 mg L⁻¹), 23 chemical elements were determined in control and Se-fortified plants using ICP-MS. Against the backdrop of plant growth stimulation, the concentration of macroelements did not change significantly in roots, increased in leaves due to high Ca and Mg levels, and decreased in seeds (from 16,959 to 11,997 mg kg⁻¹ d.w.). A decrease in Fe, Mn, Cu, Zn, and Co was recorded in leaves (1.37–1.69 times) and seeds (1.38–3.07 times), with insignificant changes in mineral profile in roots. Accordingly, the root–leaf Transfer Factor (TF) of Ca and Mg increased while leaf–seed TF decreased. Root–leaf TF of K, Na, and P decreased due to Se supply. No changes were recorded for Si TFs or for Cu leaf–seed TF. On the other hand, the TF increased for B (root–leaf) and Zn (leaf–seed). Changes in potentially toxic element concentrations due to Se supply showed negative correlations with the atomic weight of elements (roots r = −0.886; leaves r = −0.931; p < 0.001, and seeds r = −0.867; p < 0.005). Similar relationships for several other plant species (Artemisia annua L.; Allium ursinum L.; Brassica rapa subsp. rapa L.) and a lack of corresponding correlations in other crops (Allium sativum, Allium cepa, Brassica oleracea) indicate the need for further mineral profile investigations in Se-fortified plants.