In light of climate change, pedunculate oak (Q. robur L.) was marked as the most threatened European tree species. Pedunculate oak is particularly jeopardized by powdery mildew disease caused by Erysiphe alphitoides. We hypothesized that priming of this tree species with ectomycorrhizal fungi could mitigate biotic stress and produce bioprotective properties against the disease. In this study, we have compared oaks’ foliar physiological and biochemical responses upon infection with E. alphitoides in the presence and absence of ectomycorrhizal fungi (ECM). The main aim of this study was to inspect how ECM modulate an oak’s biochemical response to infection with E. alphitoides, particularly at the level of the accumulation of the main polyamines (putrescine, spermidine, and spermine), soluble osmolytes (proline and glycine betaine), and phenolics (total phenolic content, flavonoids, and condensed tannins). A polyamine quantification was performed after derivatization by using high-performance liquid chromatography (HLPC) coupled with fluorescent detection. Oak seedlings inoculated with ECM fungi exhibited significantly higher levels of putrescine, spermine, and proline compared to non-inoculated seedlings, indicating the priming properties of the ECM. E. alphitoides caused an increase in individual and total polyamine content and lipid peroxidation in oak leaves regardless of the effect of ECM, while causing a decrease in physiological and antioxidative parameters and water use efficiency (WUE). Common biochemical parameters may contribute to understanding the underpinning plant defense mechanisms in three-way interactions among plants and pathogenic and ectomycorrhizal fungi and can be used as reliable adaptability descriptors in the context of climate change.

Numerous medical studies have shown the positive effects of forests on different aspects of human health. This study deals with the content of major terpenes in dominant coniferous species in Tara National Park, Serbia, in order to explore the potential for the development of a novel health tourism programme based on forest therapy. Main terpenes were analysed using a headspace-sampling technique coupled with gas-chromatography-mass spectrometry (Head-space-GC/MS). Needles of fir and spruce growing in the vicinity of hiking trails were investigated for possibilities to perform such therapy. Major detected terpenes were α-cadinol and spathulenol previously described as antiviral, antitumor, antimicrobial and immunomodulatory agents. The results of the study were favourable and worked well with the existing walking infrastructure in the observed area of the Tara Mountain, as they act as invaluable resources for designing the structured forest bathing walks. The study not only adds to the knowledge in the environmental and public health realm but also to tourism and sustainability studies.

It is considered that different plant organic compounds, known as phytoncides are creditable for positive effects of Forest therapy on human health. Ongoing pandemic has also put these compounds in research focus considering potential use for novel corona virus treatment. This research was conducted in order to examine the potential of Tilia cordata Mill. considering volatile organic compounds (VOCs) content for the use in Forest therapy. In order to determine qualitative and quantitative content of phytoncides, as well the variability among genotypes growing in the same environmental conditions, leaf samples from genotypes of T. cordata were collected from the Fruška gora (Serbia) during 2019. VOCs determined in fresh herbal material were analyzed by HeadspaceGC/MS and VOCs determined in essential oil were obtained by GC/MS. The results showed the presence of 17 different phytoncides (monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, oxygenated sesquiterpenes, aliphatic compounds and diterpenes) in all tested genotypes. According to the mean values of the obtained results, the most abundant classes of phytoncides among the examined genotypes were monoterpene hydrocarbons (87.05), followed by aliphatic compounds (36.59) and oxygenated sesquiterpenes (34.60). The highest coefficient of variation (CV) among phytoncide content in tested T. cordata genotypes has been observed within oxygenated monoterpenes (43.12%), sesquiterpene hydrocarbons (28.18%), and diterpenes (27.04%). Some individual monoterpene hydrocarbons, such as o-cymene (19.92%) and a-pinene (17.40%) had the highest CV in terms of its presence in analyzed genotypes. In addition, the principal component analysis (PCA) showed more notable clustering within the VOCs determined in essential oil in comparison to VOCs determined in fresh herbal material. Considering the phytoncide content detected in T. cordata leaves, this species has high potential for the use in human health improvement within Forest therapy.

Multiple positive effects that forests have on human health and overall well-being have been reported widely in the literature. Still, multiple elements of this relationship remain unidentified and unexplained. In this study, the composition of leaf volatile organic compounds (BVOCs) content in three common coniferous species: the Austrian pine (Pinus nigra), Scots pine (Pinus sylvestris) and Spruce (Picea abies), was analyzed. The specificity of BVOCs content in the examined species and their genotypes is observed as a plant potential to evaporate these organic compounds and potentially improve human health and well-being. Principal component analysis applied on BVOCs content among species showed significant differences between compounds that have previously been characterized as having positive effects on human health by acting as anticancer, anti-inflammatory, antiviral and antibacterial. Variations among genotypes of the investigated species were observed in the content of BVOCs relevant for human health improvement, such as limonene, terpinolene, β-pinene, linalool, camphene, camphor, citronellol and α-cadinol. The observed intra- and inter-species variations in the BVOCs content provide an appropriate base for further research on the forest–human health relationship, breeding and selection of the most suitable genotypes for human health improvement, and could I mpact the sustainable management of forests.

Besides anthropogenic factors, climate change causes altered precipitation patterns that indirectly affect the increase of heavy metals in soils due to hydrological effects and enhanced leaching (i.e., Cd and Ni), especially in the vicinity of mines and smelters. Phytoextraction is a well-known, powerful “green” technique for environmental clean-up that uses plants to extract, sequester, and/or detoxify heavy metals, and it makes significant contributions to the removal of persistent inorganic pollutants from soils. Poplar species, due to their growth features, high transpiration rate, large biomass, and feasible reproduction represent great candidates for phytoextraction technology. However, the consequences of concomitant oxidative stress upon plant metabolism and the mechanism of the poplar’s tolerance to heavy metal-induced stress are still not completely understood. In this study, cuttings of poplar species (Populus deltoides W. Bartram ex Marshall) were separately exposed to two heavy metals (Cd2+ and Ni2+) that were triple the maximum allowed amount (MAA) (according to national legislation). The aim of the study was to estimate the effects of heavy metals on: (I) the accumulation of free and conjugated polyamines, (II) plant hormones (including abscisic acid-ABA and indole-3-acetic acid-IAA), and (III) the activities of different antioxidant enzymes at root and leaf levels. By using the selected ion monitoring (SIM) mode of gas chromatography with mass spectrometry (GC/MS) coupled with the isotopically labeled technique, amounts of ABA and IAA were quantified, while polyamine amounts were determined by using high-performance liquid chromatography (HPLC) with fluorometric detection after derivatization. The results showed that P. deltoides responded to elevated concentrations of heavy metals in soils by exhibiting metal- and organ-specific tolerance. Knowledge about tolerance mechanisms is of great importance for the development of phytoremediation technology and afforestation programs for polluted soils.