Utilization of arbuscular mycorrhizal fungi (AMF) for enhancing growth and development as well as production of essential oil in aromatic plants has been increasingly drawing research interest. In order to assess the AMF effects on different aromatic species, an open-field experiment was carried out using Artemisia dracunculus (tarragon), Lavandula angustifolia (lavender) and Hyssopus officinalis (hyssop). AMF stimulated the growth of tarragon and lavender plants, whereas hyssop showed a slight developmental slowing; nonetheless, a significant increase in essential oil content in the three species was seen. AMF application increased the biomass of A. dracunculus and H. officinalis by 20-35%. No differences in antioxidant activity and phenolics content were recorded at harvest between the control and AMF-inoculated plants, but the latter showed a significant increase in antioxidant status upon storage at high temperature and humidity compared to the untreated control. The enhancement of abiotic stress resistance during storage in plants inoculated with AMF was the highest in A. dracunculus, and the lowest in H. officinalis, while the untreated control plants showed a significant decrease in phenolics, ascorbic acid and chlorophyll content, as well as antioxidant activity, upon the abiotic stress. AMF inoculation differentially affected the mineral composition, increasing the accumulation of Se, I and Zn in A. dracunculus, and decreasing the levels of heavy metals and Co, Fe, Li, Mn in H. officinalis. Based on the outcome of the present research, AMF inoculation resulted in a significant enhancement of the overall performances of A. dracunculus, L. angustifolia and H. officinalis, and also in the improvement of plant antioxidant status upon storage in stress conditions.

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The unique biological properties of A. annua have stimulated the research on its cultivation in different regions of the world. In this study, the effect of the Se and nano-Si supply on the yield, biochemical characteristics and mineral content of A. annua was investigated. Growth stimulation and a significant increase in the antioxidant status were recorded under Se and nano-Si foliar application. A decrease in the number of essential oil components and significant changes in the essential oil amount and composition led to significant phenophase shifts: nano-Si significantly stimulated eucalyptol and artemisia ketone accumulation and decreased germacrene D production, whereas Se demonstrated the opposite effect. A joint Se and nano-Si supply significantly decreased the camphor content and increased artemisia ketone and artemisinin levels by 1.3–1.5 times. Se/Si supplementation affected the macro- and microelements content, causing either a redistribution of leaves/stems elements (Al, Li and Zn) or a significant decrease in Ca, Mg, K, B, Cu, Fe and Mn concentrations in leaves, with no signs in growth inhibition or a decrease in the photosynthetic pigments content. The biofortification of A. annua with Se singly or in combination with nano-Si resulted in the synthesis of products with a Se content of as much as approximately 16% of the daily adequate Se consumption level (ACL) when using 5 g day-1 as a spice, or 36% of ACL when using 50 mL of tea infusion (1:2, v/w). The results indicated a high possibility of Se and nano-Si application toward the regulation of A. annua growth, biochemical characteristics (including essential oil and artemisinin) and mineral content.

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.

The ‘edge’ effect is considered one of the fundamental ecological phenomena essential for maintaining ecosystem integrity. The properties of plant outer tissues (root, tuber, bulb and fruit peel, tree and shrub bark, leaf and stem trichomes) mimic to a great extent the ‘edge’ effect properties of different ecosystems, which suggests the possibility of the ‘edge’ effect being applicable to individual plant organisms. The most important characteristics of plant border tissues are intensive oxidant stress, high variability and biodiversity of protection mechanisms and high adsorption capacity. Wide variations in morphological, biochemical and mineral components of border tissues play an important role in the characteristics of plant adaptability values, storage duration of roots, fruit, tubers and bulbs, and the diversity of outer tissue practical application. The significance of outer tissue antioxidant status and the accumulation of polyphenols, essential oil, lipids and minerals, and the artificial improvement of such accumulation is described in connection with plant tolerance to unfavorable environmental conditions. Methods of plant ‘edge’ effect utilization in agricultural crop breeding, production of specific preparations with powerful antioxidant value and green nanoparticle synthesis of different elements have been developed. Extending the ‘edge’ effect phenomenon from ecosystems to individual organisms is of fundamental importance in agriculture, pharmacology, food industry and wastewater treatment processes.