Search Results (53)

Scots pine (Pinus sylvestris L.) is a key species in boreal forests, valued both economically and ecologically, in part due to its associations with foliar fungi. These fungi influence plant health, nutrient cycling, and resistance induction. To investigate these interactions, we collected 1367 needle and shoot samples across 12 plus tree genotypes grown in 4 progeny trials in Estonia. Amplifying the ITS1-5.8S-ITS2 gene region, we obtained over 1.3 million high-quality sequences and identified 1261 fungal OTUs at the 98% species hypothesis level. Among the identified OTUs, 24.6% were classified as saprotrophic and 18.2% as pathogenic fungi. Fungal diversity varied significantly between tree tissue types, progeny trial locations, and plus tree origins. Fungal community composition varied across tissue types, with older needles tending to harbor more complex communities. Plus trees 593 and 267-1 progenies stood out for their high phyllosphere fungal richness, and genotype-specific correlations indicated associations between fungal diversity and tree height or needle retention, suggesting potential genotype-dependent effects on tree performance. Heritability of fungal diversity between ramets in seed orchard and progeny trees was found for saprotrophic fungi but was negligible for total fungi and pathogens, indicating strong influence of microclimate conditions. These findings underscore the potential value of integrating fungal community traits into Scots pine breeding programs. Considering microbial associations alongside traditional growth traits may help identify genotypes better suited for future forestry needs under changing environmental conditions. Additionally, Setomelanomma holmii is reported here as a new fungal pathogen on Scots pine shoots in Estonia. Full article

Needle cast (Lophodermium seditiosum Minter, Staley & Millar) in Scots pine (Pinus sylvestris L.) and European ash (Fraxinus excelsior L.) dieback (Hymenoscyphus fraxineus (T. Kowalski) Baral, Queloz & Hosoya) are among the most destructive forest and tree plantation diseases in Europe, threatening not only targeted plant species but also the whole ecosystem. While considerable research effort has focused on microbial antagonists against ash dieback, comparable investigations into needle cast biocontrol remain virtually absent from the literature. Here, isolated microbial antagonists from European ash and Scots pine were evaluated for their efficacy against respective pathogens. In vitro dual-culture assays revealed bacteria with strong inhibitory effects on pathogen growth, as well as multiple plant growth-promoting traits (PGPTs). It was found that bacteria from the genera of Pantoea, Erwinia, Priestia, and Pseudomonas inhibited the growth of H. fraxineus by ≥70%. Most significantly, our investigation revealed that bacteria isolated from Scots pine, belonging to the genera Pseudomonas, Bacillus, and Priestia, inhibited the growth of L. seditiosum by 50% to 80%, representing one of the first reported bacterial antagonisms for this neglected pathogen. All isolates were positive for at least two PGPTs, primarily due to mineralization of organic phosphate and the production of siderophores. The dual functional traits of isolated bacteria highlight their potential application in integrated forest protection strategies, particularly for the previously overlooked L. seditiosum pathosystem. Full article

Historically, wood has been among the main materials used in heritage buildings. However, the species and mechanical properties of these elements are often unknown. This uncertainty complicates safety assessment calculations, aggravated by the natural variability of the wood properties. The aim of this work is to assess the density of wooden elements in service using semi-destructive techniques that retain the integrity of structural elements. This research had two phases. First, penetration resistance tests were carried out on laboratory scale on Pinus sylvestris L. wood samples taken from 18th, 19th, and 20th century heritage buildings in Lisbon, Portugal. Later, a field study was carried out on wooden elements from the same buildings, involving needle penetration, core drilling, and moisture content determination tests. The laboratory test results showed a strong correlation between the needle penetration depth and wood density, with an R² value of 0.76. The results of the field study indicated that the density estimated by the needle penetration test correlated effectively with the measured density of extracted cores after moisture correction, with an R² of 0.99. In conclusion, the experimental results confirm that penetration resistance and moisture tests are reliable and practical for estimating wood density under in-service conditions. Full article

Dothistroma needle blight (DNB) is one of the most significant diseases of conifers, causing premature defoliation, growth reduction, and, in extreme cases, mortality. Histological analysis was undertaken on inoculated seedlings of three different seed sources of Pinus sylvestris L. to investigate the process of infection and degradation of needle tissue on this host species. Seedlings were inoculated using a single spore isolate of Dothistroma septosporum (Doroguine) M. Morelet (D636) from northern Scotland. Mesophyll degradation in the needles occurred by four weeks after inoculation; collapse of mesophyll, bundle sheath tissues, and tracheids by five weeks; and eruption of fruiting bodies in near proximity to stomatal openings by six weeks. Significantly greater collapse of mesophyll during the early stages of infection occurred in the Austrian provenance compared with the United Kingdom provenance, although in the later stages of infection, this difference disappeared. Furthermore, disease severity, assessed as the proportion of needles with D. septosporum conidiomata on each tree, was not significantly different between seed sources. Full article

Potentially toxic elements (PTEs) have steadily become a serious environmental problem, especially regarding brownfields chosen for reuse, e.g., as a residential area. “Norra Hamnstaden” in Lidköping (Sweden) has a long history of industrial activity, including porcelain production with the resultant industrial waste deposited close by resulting in elevated levels of metals used for porcelain glazes, especially lead. To estimate the bioavailability of twelve PTEs (As, Ba, Pb, Cd, Co, Cu, Cr, Mn, Mo, Ni, V, Zn), their uptake by birches (Betula pendula) as well as Scots pines (Pinus sylvestris) was investigated through analyzing their leaves. Sampling was carried out on five trees once per month in the period from May to August. Different uptake patterns were observed for birches and pines, for the latter even varying with age. The birch samples showed higher contents of nickel, cobalt, molybdenum, and lead compared to the reference trees. Also, the pine needles had elevated lead levels, although by a lower factor. Birch leaves revealed surprising patterns of elevated element bioaccumulation factors, with barium reaching up to eight, offering the possibility to limit analyses to plant material for risk assessments instead of soil analysis. Full article

The diversity of foliar fungal endophyte communities was examined in three economically and ecologically important pine species in Scotland: Scots pine, Corsican pine and lodgepole pine. Two plantation sites comprising all three species were selected in climatically contrasting parts of Scotland and were sampled in late spring by collecting healthy needles from two age classes. Surface sterilisation was carried out before obtaining cultures of fungal isolates, and representatives of common sterile morphotypes were sequenced to determine taxonomic placement. Overall relative proportions of the dominant taxa across sites, tree species and needle age classes were as follows: Anthostomella spp. (52%), Lophodermium seditiosum (17%) and Desmazierella acicola (7%). Many other less frequent taxa were recovered. The results agreed with previous endophyte studies in that the combined effects of site and tree species produced unique endophytic fungal assemblages. Phylogenetic analyses revealed potential sub-species variation associated with site in Anthostomella pinea. Our findings point to the potential naturalisation of European fungal endophytic species (e.g., Anthostomella spp.) in Scottish pine plantations, particularly in association with Corsican pine. Full article

Background/objectives: Methyl jasmonate is a plant signaling molecule involved in a wide range of functions, including stress responses. This study investigates the relative differential expression of microRNAs and their target genes in response to methyl jasmonate treatment of Scots pine needles. Methods: A combined strategy of high-throughput sequencing and in silico prediction of potential target genes was implemented. Results: a total of 58 differentially expressed (DE) microRNAs (miRNAs) (43 up-regulated and 15 down-regulated), belonging to 29 miRNA families, were identified. The 41 DE miRNAs from 17 families were conifer-specific miRNA families—miR946, miR947, miR950, miR1312, miR1313, miR1314, miR3693, miR3107, miR11452, miR11466, miR11487, miR11490, miR11504, miR11511, miR11532, miR11544, and miR11551. The other DE miRNAs (miR159, miR164, miR169, miR396, miR397, miR398, miR408, miR535) were conserved miRNAs, which are also found in angiosperm species. Transcriptome analysis identified 389 gene transcripts with 562 miRNA-target sites targeted by 57 of the 58 DE miRNAs. Of these, 250 target genes with 138 different GO annotations were found for the 41 DE conifer-specific conserved miRNAs. Conclusions: The 26 DE miRNAs from 14 DE miRNA families, of which almost all (12 families, 24 miRNAs) are conifer specific, and were associated with 68 disease resistance and TMV resistance proteins, TIR-NBS-LRR, LRR receptor-like serine/threonine-protein kinase, putative CC-NBS-LRR protein, and putative NBS-LRR protein target transcripts with 29 target gene GO term descriptions. Some of the genes targeted by conifer-specific miRNAs have been previously reported to be targeted by other miRNAs in angiosperms, indicating that the miRNA-target gene regulation system can vary between species. Full article

This study investigated carbon sequestration potential in reforesting agricultural lands with prevalence of Scots pine (Pinus sylvestris L.) in the “Nasibash” site of the Eurasian Carbon Polygon, located in the Republic of Bashkortostan, Russia. The research focused on analyzing carbon stocks in different ecosystem components (tree stand, herbaceous layer, litter, and soil) across various stages of succession, including fallow land, hayfield, and four stages of Scots pine reforestation. We found that needles during the first stage of succession were characterized by the highest carbon sequestration, while the lowest was in underground phytomass (roots). The tree stand exhibited a higher potential for carbon sequestration in stem wood, branches, and needles compared to other components. The highest carbon accumulation in the tree layer was observed in the stem phytomass at the fourth stage of reforestation, while the highest phytomass accumulation in the herbaceous layer was in the root mass at the fourth stage of succession. The study revealed that the highest organic carbon content in the topsoil layer was observed in areas dominated by herbaceous vegetation, with a decrease in carbon content as the stage of succession increased. The highest carbon content was found in tree pines at the first stage of succession. The research highlighted the importance of considering conversion factors for different stages of reforestation, as the average carbon content in vegetation was 20% higher than the approved conversion factors for young tree stands. Overall, the study demonstrates the significant potential of Scots pine reforestation on former agricultural lands for carbon. The findings suggest that these territories play a decisive role in future environmental and climate projects, contributing to the decarbonization efforts. Full article

Understanding needle biomass turnover rates in Scots pine (Pinus sylvestris L.) stands is crucial for modelling forest ecosystem dynamics and nutrient cycling. This study examined needle litterfall and biomass turnover in Scots pine stands of varying ages in temperate forests (western Poland). The research focused on determining how stand age affects needle biomass, litterfall and the associated turnover rates. Data were collected from 20 Scots pine stands aged 26 to 90 years, and needle litterfall was measured and analysed in relation to stand characteristics such as age, density and biomass. The average annual needle litter production of the sampled Scots pine stands was 2008 kg·ha⁻¹·year⁻¹, similar to the values previously reported for this tree species in other temperate forests in Europe. The average needle biomass turnover rate for sampled Scots pine stands was 23.4%. We could not support the hypothesis that this parameter depended on the age of the Scots pine stand. The needle biomass turnover rate showed a positive correlation with crown length and a negative correlation with stand density due to the very weak correlations; however, further research is needed to confirm these relationships. Despite this, the parameter can be used to estimate needle litterfall and can be applicable to conditions corresponding to those of temperate forests in Central and Western Europe. This study also highlights the need for further research on needle biomass turnover in temperate forests to improve the accuracy of carbon and nutrient cycling models. This work contributes to a deeper understanding of the role of needle litterfall in maintaining soil fertility and forest productivity, offering insights into sustainable forest management and conservation strategies. Full article

We studied the recovery of the growth and physiological parameters of Scots pine seedlings after long-term zinc toxicity. The removal of excess zinc from the nutrient solution resulted in the rapid recovery of primary root growth but did not promote the initiation and growth of lateral roots. The recovery of root growth was accompanied by the rapid uptake of manganese, magnesium, and copper. Despite the maximum rate of manganese uptake by the roots, the manganese content in the needles of the recovering plants did not reach control values during the 28 days of the experiment, unlike magnesium, iron, and copper. In general, the recovery of ion homeostasis eliminated all of the negative effects on the photosynthetic pigment content in the needles. However, these changes, along with recovery of the water content in the needles, were not accompanied by an increase in the weight gain of the recovering seedlings compared with that of the Zn-stressed seedlings. The increased accumulation of phenolic compounds in the needles persisted for a long period after excess zinc was removed from the nutrient solution. The decreased lignin content in the roots and needles is a characteristic feature of Zn-stressed plants. Moreover, the removal of excess zinc from the nutrient solution did not lead to an increase in the lignin content in the organs. Full article

Background and Aims: Secondary plant metabolites, including organic acids and phenolic compounds, have a significant impact on the properties of organic matter in soil, influencing its structure and function. How the production of these compounds in foliage that falls to the forest floor as litterfall varies across tree age and seasonality are of considerable interest for advancing our understanding of organic matter dynamics. Methods: Monthly, we collected fallen needles of Scots pine (Pinus sylvestris L.) across stands of five different age classes (20, 40, 60, 80, and 100 years) for one year and measured the organic acids and phenolic compounds. Results: Seven low-molecular-weight organic acids and thirteen phenolic compounds were detected in the litterfall. No differences were observed across stand age. Significant seasonal differences were detected. Most compounds peaked during litterfall in the growing season. Succinic acid was the most prevalent organic acid in the litterfall, comprising 78% of total organic acids (351.27 ± 34.27 µg g^− 1), and was 1.5 to 11.0 times greater in the summer than all other seasons. Sinapic acid was the most prevalent phenolic compound in the litterfall (42.15 µg g^− 1), representing 11% of the total phenolic compounds, and was 39.8 times greater in spring and summer compared to autumn and winter. Growing season peaks in needle concentrations were observed for all thirteen phenolic compounds and two organic acids (lactic, succinic). Citric acid exhibited a definitive peak in late winter into early spring. Conclusions: Our results highlight the seasonal dynamics of the composition of secondary plant metabolites in litterfall, which is most different at the onset of the growing season. Fresh inputs of litterfall at this time of emerging biological activity likely have seasonal impacts on soil’s organic matter composition as well. Full article

Little is known about how the degree of mixing various forest-forming species affects forest floor hydrology. We evaluated the water storage capacity of the resulting litter layer by mixing the litterfall of Scots pine and sessile oak and studying their decomposition time. We prepared 90 artificial samples containing pure pine litter, pure oak litter, and mixed pine–oak litter with varying shares of pine needles. These samples were subjected to 15 months of decomposition in soil. After every three months of decay, some samples were removed from the soil, and their water storage capacity, bulk density, and C:N ratio were evaluated. Our findings indicate that samples with the greatest water storage capacity had a low C:N ratio and a predominant share of oak leaves. Conversely, samples with a high C:N ratio and a predominant share of pine needles had the lowest water storage capacity. After 12 and 15 months of decomposition, the water storage capacity increased by more than 52% compared to the initial water capacity of the samples. The highest increase in water storage capacity (>40%) was observed in samples with a predominant share of oak leaves, while the lowest (approximately 28%) was recorded in samples with 80 and 100% of pine needles. Our findings suggest that introducing mixed-species stands, with deciduous species as the predominant component, can yield several ecological benefits, such as an increased ability to store water in forest floor. Full article

Black spot needle blight is a minor disease in Mongolian Scots pine (Pinus sylvestris var. mongolica) caused by Pestalotiopsis neglecta, but it can cause economic losses in severe cases. Sodium pheophorbide a (SPA), an intermediate product of the chlorophyll metabolism pathway, is a compound with photoactivated antifungal activity, which has been previously shown to inhibit the growth of P. neglecta. In this study, SPA significantly reduced the incidence and disease index and enhanced the chlorophyll content and antioxidant enzyme activities of P. sylvestris var. mongolica. To further study the molecular mechanism of the inhibition, we conducted a comparative proteomic analysis of P. neglecta mycelia with and without SPA treatment. The cellular proteins were obtained from P. neglecta mycelial samples and subjected to a tandem mass tag (TMT)-labelling LC-MS/MS analysis. Based on the results of de novo transcriptome assembly, 613 differentially expressed proteins (DEPs) (p < 0.05) were identified, of which 360 were upregulated and 253 downregulated. The 527 annotated DEPs were classified into 50 functional groups according to Gene Ontology and linked to 256 different pathways using the Kyoto Encyclopedia of Genes and Genomes database as a reference. A joint analysis of the transcriptome and proteomics results showed that the top three pathways were Amino acid metabolism, Carbohydrate metabolism, and Lipid metabolism. These results provide new viewpoints into the molecular mechanism of the inhibition of P. neglecta by SPA at the protein level and a theoretical basis for evaluating SPA as an antifungal agent to protect forests. Full article

The influence of short-term additional white (WL), red (RL) and far-red (FRL) light and combined RL+FRL on the physiological morphological and molecular characteristics of two-year-old Scots pine plants grown in a greenhouse under sunlight was studied. Additional RL and RL+FRL increased the number of xylem cells, transpiration and the expression of a group of genes responsible for the biosynthesis and signaling of auxins (AUX/IAA, ARF3/4, and ARF16) and brassinosteroids (BR-α-RED and BRZ2), while the expression of genes related to the signaling pathway related to jasmonic acid was reduced. Additionally, WL, RL and RL+FRL increased the content of proanthocyanidins and catechins in young needles; however, an increase in the expression of the chalcone synthase gene (CHS) was found under RL, especially under RL+FRL, which possibly indicates a greater influence of light intensity than observed in the spectrum. Additional WL increased photosynthetic activity, presumably by increasing the proportion and intensity of blue light; at the same time, the highest transpiration index was found under RL. The results obtained indicate that the combined effect of additional RL+FRL can accelerate the development of pine plants by increasing the number of xylem cells and increasing the number of aboveground parts but not the photosynthetic activity or the accumulation of secondary metabolites. Full article

This article presents the results of research on the influence of polymetallic-dust aerial emissions on the pollution levels in the soil and plants by heavy metals, which have been under the impact of the “Severonickel” smelter complex on the Kola peninsula (Russia) for more than 40 years. Research using soil and plant indicators was carried out at monitoring plots in the years 1980–1999 (with high aerotechnogenic emissions) and 2000–2019 (with low aerotechnogenic emissions). The organic horizon (forest litter) of the Al-Fe-humus podzol, assimilation organs of Vaccinium myrtillus L., V. vitis-idaea L., V. uliginosum L., Empetrum hermaphroditum Hagerup, and Pinus sylvestris L. as well as tree rings of Scots pine were used for bioindication research. The content of heavy metals was determined using the AAS method. During these time periods, the emissions of polymetallic dust decreased 3.5 fold, while the level of forest litter contamination with heavy metals in the buffer and impact zones increased by 2–5 times, resulting in increased phytotoxicity of the soil and reduced habitat quality for forest plants. At present, the content of Ni and Cu in the leaves (needles) of the plant indicators in the impact zone has decreased by 3–8 times compared with 1980–1999 but their elevated levels pose a potential health risk. The decrease in atmospheric emissions of pollutants led to a 1.5-fold increase in the width of the annual rings of pine trunks in the impact zone, which may indicate the beginning of the recovery of pine-trunk-wood productivity. Full article