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Increasing atmospheric CO2 levels change the elemental composition in plants, altering their nutritional quality and affecting consumers and ecosystems. Ecological stoichiometry provides a framework for investigating how CO2-driven nutrient dilution in pollen affects bees by linking changes in pollen chemical element proportions to the nutritional needs of bees. We investigated the consequences of five years of Free Air CO2 Enrichment (FACE) in a mature oak-dominated temperate forest on the elemental composition of English oak (Quercus robur) pollen. We measured the concentrations and proportions of 12 elements (C, N, P, S, K, Na, Ca, Mg, Cu, Zn, Fe, and Mn) in Q. robur pollen-bearing flowers collected from the Birmingham Institute for Forest Research (BIFoR) FACE facility. An elevated CO2 (eCO2) level of 150 ppm above ambient significantly reduced the S, K, and Fe levels and altered the multi-element ratio, with different elements behaving differently. This shift in pollen multi-element composition may have subsequent cascading effects on higher trophic levels. To assess the impact on bees, we calculated the stoichiometric mismatch (a measure of the discrepancy between consumer needs and food quality) for two bee species, Osmia bicornis (red mason bee) and Apis mellifera (honey bee), that consume oak pollen in nature. We observed stoichiometric mismatches for P and S, in pollen under eCO2, which could negatively affect bees. We highlight the need for a comprehensive understanding of the changes in pollen multi-element stoichiometry under eCO2, which leads to nutrient limitations under climate change with consequences for bees. [ABSTRACT FROM AUTHOR]

Trees affect the biotic and abiotic properties of the soil in which they grow. Tree species-specific effects can persist for a long time, even after the trees have been removed. We investigated to what extent such soil legacies of different tree species may impact tree seedlings in their emergence and growth. We performed a plant–soil feedback experiment, using soil that was conditioned in plots that vary in tree species composition in Białowieża Forest, Poland. Soil was taken from plots varying in proportion of birch, hornbeam, pine, and oak. In each soil, seeds of the same four target species were sown in pots. Seedling emergence and growth were monitored for one growing season. To further explore biotic implications of soil legacies, ectomycorrhizal root tip colonization of oak, a keystone forest species, was determined. We found no effect of soil legacies of tree species on the emergence measures. We, however, found a clear negative effect of pine legacies on the total biomass of all four seedling species. In addition, we found relationships between the presence of pine and soil fertility and between soil fertility and root tip colonization. Root tip colonization was positively correlated with the biomass of oak seedlings. We conclude that tree species can leave legacies that persist after that species has been removed. These legacies influence the growth of the next generation of trees likely via abiotic and biotic pathways. Thus, the choice of species in today's forest may also matter for the structure and composition of future forests. [ABSTRACT FROM AUTHOR]

Abstract Key Message Leaves of seedlings from five oak species (Quercus robur L.; Q. pubescens L.; Q. suber L.; Q. afares Pomel; Q. ilex L.) displayed large, mainly inter-specific, differences in leaf mass-to-area ratio (LMA) and lignin content, as well as in the 13C composition of bulk leaf biomass. The variation in leaf lignin content and LMA did not impact the offset between the 13C composition measured in bulk leaf material versus soluble sugars. This observation, as well as the similar correlations between intrinsic leaf water use efficiency and the 13C compositions of bulk material or soluble sugars extracted from leaves, confirms their reliable use as a proxy for the former even when there is a large variation in LMA or lignin among samples. Context Carbon isotope composition (δ 13 C) of bulk leaf biomass is frequently used as a proxy for intrinsic water use efficiency (iWUE) in large-scale intra- and inter-specific comparisons. However, post-photosynthetic 13C discrimination during the synthesis of lignin combined with differences in leaf mass-to-area ratio (LMA) may bias the relationship between δ 13 C of bulk leaf matter and iWUE and thus its use as a proxy of iWUE. Aims To quantify the impact of differences in lignin content and LMA on the relationship between δ 13 C of bulk leaf biomass and iWUE over a large gradient of lignin contents across five oak species (deciduous: Quercus robur, Q. pubescens, Q. afares and evergreen: Q. ilex and Q. suber). Methods We measured lignin content, LMA, and δ 13 C of bulk leaf biomass and of soluble sugars extracted from the leaves, as well as intrinsic water use efficiency (derived from leaf gas exchange) in seedlings of the five oak species grown under common conditions in a greenhouse and measured in a climate chamber. Results There was a large range (mainly across species) in lignin content (4 to 33%) and LMA (60–180 g m−2). δ 13 C of bulk leaf biomass and soluble sugars were tightly correlated, showing a significant mean offset of − 0.4‰. This offset was stable across species and not correlated to the lignin content of the leaves. A very loose correlation was found between the offset and LMA, mainly due to one species. Conclusion Our results are a demonstration that potential variations in leaf lignin content or LMA have no or only a little effect on the δ 13 C of bulk leaf biomass. They are unlikely to cause a bias when using bulk leaf δ 13 C as a proxy for variations in intrinsic water use efficiency among Mediterranean and temperate broad-leaf forest tree species.

Pedunculate oak is an economically and ecologically very valuable species at the European level and for Bosnia and Hercegovina, and research into variation of this species is very important. In 2007, pedunculate oak leaf material was collected in 27 populations in Bosnia and Herzegovina along with seeds, which were used to establish a provenance trial. In the trial, leaves were collected in 2021, and 14 morphological traits were measured in both types of material. Analysis of variance showed generally non-significant differences between generations, but significant variation among populations and population-by-generation interactions. However, the correlations between generations were non-significant for most traits, and neither were the correlations with climatic parameters. The results indicate both genetic and environmental effects on leaf morphology. The utility of leaf morphology for gene conservation is shortly discussed.

Key Message: Leaves of seedlings from five oak species (Quercus robur L.; Q. pubescens L.; Q. suber L.; Q. afares Pomel; Q. ilex L.) displayed large, mainly inter-specific, differences in leaf mass-to-area ratio (LMA) and lignin content, as well as in the 13C composition of bulk leaf biomass. The variation in leaf lignin content and LMA did not impact the offset between the 13C composition measured in bulk leaf material versus soluble sugars. This observation, as well as the similar correlations between intrinsic leaf water use efficiency and the 13C compositions of bulk material or soluble sugars extracted from leaves, confirms their reliable use as a proxy for the former even when there is a large variation in LMA or lignin among samples. Context: Carbon isotope composition (δ13C) of bulk leaf biomass is frequently used as a proxy for intrinsic water use efficiency (iWUE) in large-scale intra- and inter-specific comparisons. However, post-photosynthetic 13C discrimination during the synthesis of lignin combined with differences in leaf mass-to-area ratio (LMA) may bias the relationship between δ13C of bulk leaf matter and iWUE and thus its use as a proxy of iWUE. Aims: To quantify the impact of differences in lignin content and LMA on the relationship between δ13C of bulk leaf biomass and iWUE over a large gradient of lignin contents across five oak species (deciduous: Quercus robur, Q. pubescens, Q. afares and evergreen: Q. ilex and Q. suber). Methods: We measured lignin content, LMA, and δ13C of bulk leaf biomass and of soluble sugars extracted from the leaves, as well as intrinsic water use efficiency (derived from leaf gas exchange) in seedlings of the five oak species grown under common conditions in a greenhouse and measured in a climate chamber. Results: There was a large range (mainly across species) in lignin content (4 to 33%) and LMA (60–180 g m−2). δ13C of bulk leaf biomass and soluble sugars were tightly correlated, showing a significant mean offset of − 0.4‰. This offset was stable across species and not correlated to the lignin content of the leaves. A very loose correlation was found between the offset and LMA, mainly due to one species. Conclusion: Our results are a demonstration that potential variations in leaf lignin content or LMA have no or only a little effect on the δ13C of bulk leaf biomass. They are unlikely to cause a bias when using bulk leaf δ13C as a proxy for variations in intrinsic water use efficiency among Mediterranean and temperate broad-leaf forest tree species. [ABSTRACT FROM AUTHOR]

Oak gall wasps have evolved strategies to manipulate the developmental pathways of their host to induce gall formation. This provides shelter and nutrients for the developing larva. Galls are entirely host tissue; however, the initiation, development, and physical appearance are controlled by the inducer. The underlying molecular mechanisms of gall formation, by which one or a small number of cells are reprogrammed and commit to a novel developmental path, are poorly understood. In this study, we sought a deeper insight into the molecular underpinnings of this process.Oak gall wasps have two generations each year, one sexual, and one asexual. Galls formed by these two generations exhibit a markedly different appearance. We sequenced transcriptomes of both the asexual and sexual generations of Neuroterus quercusbaccarum and Neuroterus numismalis. We then deployed Nanopore sequencing to generate long‐read sequences to test the hypothesis that gall wasps introduce DNA insertions to determine gall development.We detected potential genome rearrangements but did not uncover any non‐host DNA insertions. Transcriptome analysis revealed that transcriptomes of the sexual generations of distinct species of wasp are more similar than inter‐generational comparisons from the same species of wasp.Our results highlight the intricate interplay between the host leaves and gall development, suggesting that season and requirements of the gall structure play a larger role than species in controlling gall development and structure. [ABSTRACT FROM AUTHOR]

Ubiquitin-specific proteases (UBPs), the largest group of deubiquitinating enzymes (DUBs), play pivotal roles in various aspects of plant physiology including growth, development, and stress response by maintaining the ubiquitin molecule pool or removing ubiquitin from targeted proteins. While numerous studies exist on UBPs across various plant species, studies focusing on the Fagaceae family remain scarce. In this study, 20 UBP genes were identified in Quercus robur and phylogenetically classified into 12 groups, supported by domain organization and conserved motif composition. The gene structures and chromosomal localizations of these genes were elucidated. To understand the evolution of the QrUBP gene family, synteny analysis was conducted among Q. robur and five other plant species. Notably, four QrUBP genes (QrUBP3, QrUBP12A, QrUBP16, and QrUBP23) were found to have at least four isogenous gene pairs, implying important roles in the phylogenetic process of the UBP gene family. Moreover, cis-acting elements analysis reveals that the QrUBP promoters contain a large number of hormone-response elements and stress-response elements. The RT-qPCR analysis of roots, stems, and leaves indicates that some of the QrUBP genes were expressed ubiquitously, while others were organ-specific. For example, QrUBP15* was primarily expressed in roots, while QrUBP8 showed tissue-specific expression in stems. Additionally, comprehensive physicochemical and subcellular localization analyses were conducted. Collectively, this comprehensive study provides insights into the UBP gene family in Q. robur, laying a solid foundation for future investigations elucidating the functional roles of QrUBP genes in plant growth and stress responses. [ABSTRACT FROM AUTHOR]

Los robles eurosiberianos tienen una escasa y no bien conocida área de distribución en el Sistema Central oriental. Dado que consideramos que el conocimiento preciso de la Corología es una herramienta fundamental para el adecuado manejo y conservación forestal, se ha realizado un estudio pormenorizado de su presencia en este territorio. Éste se ha basado en la recopilación de información bibliográfica y procedente de bases de datos botánicas y forestales y, también, aportando nuevos datos procedentes de las prospecciones de campo realizadas entre los años 2000 y 2015, que incluyen la ubicación, extensión y características de individuos, rodales o bosques. Toda esta información se ha sometido a procesos de homogeneización y sistematización, pues procedía de distintas fuentes con diferente estructura, calidad y grado de detalle. Se han determinado 231 cuadrículas UTM de 1x1 km distintas en las que está presente de manera natural alguno de los taxones que integran el grupo, entre las que 157 cuadrículas se indican por primera vez. Además, se han seleccionado y analizado 30 poblaciones, entre las más numerosas, con mayor probabilidad de reclutamiento y persistencia en el tiempo, comprobando una mayor presencia de estos robles en la Sierra de Ayllón, siendo sus representaciones cada vez más reducidas y aisladas hacia el oeste.

Water is one of the key ecological factors that has a great impact to development and productivity of lowland species such as Quercus robur. This paper deals with water regime influence to site conditions of these species and how actually changeable soil moisture affects Q. robur. Studied area includes a protective embankment built on the river bank in order to eliminate flooding effect, which means that all needs for water these associations provide from rainfalls and groundwater. Water regime was monitored during two critical years (extremely dry and extremely wet) on four soil types – Planosol, Fluvisol and Gleysol that belong to hydromorphic (three experimental plots) and Chernozem which belongs to automorphic soils (three experimental plots), respectively. It was studied the distribution of rainfalls and groundwater during the growing seasons and how it affects total and available water amount in the soil. The main focus should be given to available water, because it is located in capillary pores and plants can utilize it. Bearing in mind rainfalls makes just 15–20% of the total water amount in the soil it is much more significant to evaluate its proportion in available water. Based on obtained results, we can deduce that much more suitable site conditions for Q. robur are present on hydromorphic soils due to much greater proportion of groundwater.

Premise: During the last centuries, the area covered by urban landscapes is increasing all over the world. Urbanization can change local habitats and decrease connectivity among these habitats, with important consequences for species interactions. While several studies have found a major imprint of urbanization on plant–insect interactions, the effects of urbanization on seed predation remain largely unexplored. Methods: We investigated the relative impact of sunlight exposure, leaf litter, and spatial connectivity on predation by moth and weevil larvae on acorns of the pedunculate oak across an urban landscape during 2018 and 2020. We also examined whether infestations by moths and weevils were independent of each other. Results: While seed predation varied strongly among trees, seed predation was not related to differences in sunlight exposure, leaf litter, or spatial connectivity. Seed predation by moths and weevils was negatively correlated at the level of individual acorns in 2018, but positively correlated at the acorn and the tree level in 2020. Conclusions: Our study sets the baseline expectation that urban seed predators are unaffected by differences in sunlight exposure, leaf litter, and spatial connectivity. Overall, our findings suggest that the impact of local and spatial factors on insects within an urban context may depend on the species guild. Understanding the impact of local and spatial factors on biodiversity, food web structure, and ecosystem functioning can provide valuable insights for urban planning and management strategies aimed at promoting urban insect diversity. [ABSTRACT FROM AUTHOR]

There are several highly damaging Phytophthora species pathogenic to forest trees, many of which have been spread beyond their native range by the international trade of live plants and infested materials. Such introductions can be reduced through the development of better tools capable of the early, rapid, and high-throughput detection of contaminated plants. This study utilized a volatilomics approach (solid-phase microextraction coupled to gas chromatography–mass spectrometry) to differentiate between several Phytophthora species in culture and discriminate between healthy and Phytophthora-inoculated European beech and pedunculate oak trees. We tentatively identified 14 compounds that could differentiate eight Phytophthora species from each other in vitro. All of the Phytophthora species examined, except Phytophthora cambivora, uniquely produced at least one compound not observed in the other species; however, most detected compounds were shared between multiple species. Phytophthora polonica had the most unique compounds and was the least similar of all the species examined. The inoculated seedlings had qualitatively different volatile profiles and could be distinguished from the healthy controls by the presence of isokaurene, anisole, and a mix of three unknown compounds. This study supports the notion that volatiles are suitable for screening plant material, detecting tree pathogens, and differentiating between healthy and diseased material. [ABSTRACT FROM AUTHOR]

The spread of neophytes (non-native plant species) challenges the conservation status and ecological integrity of forests, especially in lowland areas. Long-term resurvey studies are needed to evaluate the temporal dynamics of neophytes in forests; however, such data are scarce. In 2023, we resampled a set of 45 permanent vegetation plots (established in 1992/93) in two forest vegetation types: oak–hornbeam forests dominated by Quercus robur and colline oak–beech forests dominated by Q. petraea. Over the last 30 years, oak forests have experienced extensive oak tree mortality, with the degree of habitat degradation being greater in Q. robur forests. In the early 1990s, only three neophytes with low abundance were recorded across all plots. In the 2023 resurvey, the total number of neophytes increased to 22 species (15 herbaceous and 7 woody species), comprising 6.9% of the total species pool in the understory layer. The increase in the plot-level number and cover of neophytes was significant in plots dominated by Q. robur but not in those with Q. petraea. The most frequent neophytes were Impatiens parviflora (present in 31% of plots), Solidago gigantea (27%), Erigeron annuus (16%) and Erechtites hieraciifolia (16%). The richness and cover of neophytes were significantly affected by the tree layer cover (negative correlation) and the degree of soil disturbance (positive correlation). All neophytes established in disturbed patches, whereas the occurrence of I. parviflora was exceptional as it was able to colonize less degraded, shaded understory environments. Habitat degradation (the mortality-induced loss of stand-forming oak trees resulting in extensive tree layer cover decrease) emerged as a key driver promoting neophyte proliferation, coupled with the impact of management-induced disturbances affecting overstory and soil conditions. The spread is expected to continue or even intensify in the future because novel light regimes and disturbances make forest habitats less resistant to neophyte proliferation. [ABSTRACT FROM AUTHOR]

Abstract Key message Naturally regenerating populations of common beech, pedunculate, and sessile oaks develop strong spatial genetic structures at adult and seedling stages. Significant genetic relationship occurs between individuals growing up to 60 m apart. This indicates the minimum distance separating trees from which seeds used for reforestation should be harvested to avoid the adverse effects of excessive relatedness among offspring. Context Spatial genetic structure is an inherent characteristic of naturally regenerating plant populations and has practical implications in forests for the management of genetic resources. Aims We investigated the extent of spatial genetic structure in three broad-leaved forest tree species (common beech—Fagus sylvatica L.; pedunculate oak—Quercus robur L.; and sessile oak—Q. petraea (Matt.) Liebl.) coexisting in the same nature reserve, explored its variation among species and different life stages (adults/offspring), and tested its possible determinants. Methods We explored patterns of spatial distribution of individuals, and using microsatellites, we estimated parameters of spatial genetic structure based on kinship relationships, considering possible sources of variation. Results In adults, the strongest spatial genetic structure was found for Q. petraea (Sp = 0.0187), followed by F. sylvatica (Sp = 0.0133), and the weakest in Q. robur (Sp = 0.0080). It was uniform across different age classes in pedunculate oak but decreased with age in sessile oak. No apparent relationship between age and spatial genetic structure was found in beech. Offspring exhibited significant spatial genetic structure (ranging from 0.0122 in beech to 0.0188 in sessile oak). The cohorts of seedlings having both parents present within the study site had stronger spatial genetic structures than cohorts of seedlings with only one local parent. Conclusion Spatial genetic structure is strong in naturally regenerating populations of heavy-seeded forest trees. Pollen immigration from outside of a local forest stand can significantly decrease the extent of spatial genetic structure in offspring generations.

Abstract Introduction Aphids play an important role in agroecological contexts as pests and vectors of plant diseases. Aphid performance is closely connected to microbial endosymbionts that provide different benefits or costs to both the aphids and their hosts plants. Furthermore, the microbiome of aphids is connected to soil microbiomes via the plant. Aphid microbiome experiments usually include a pooling step, where several individuals are sequenced together to obtain sufficient DNA concentrations but pooling may blur intraspecific variations. Materials and Methods To investigate the effects of sequencing single versus pooled aphids on the results of microbiome analyses, we compared 16S rRNA/ITS amplicon libraries from pooled and single oak aphids (Tuberculatus annulatus HARTIG) under three different soil treatments. We tested whether results quantitatively or qualitatively depend on pooling aphids, prevalence‐based in silico filtering or removal of the primary endosymbiont (Buchnera aphidicola). Buchnera phylogeny, prevalence and abundance of secondary endosymbionts and effects of soil microbiota were investigated. Results Pooling leads to quantitative differences in bacteria and qualitative differences in fungal species richness, bacterial community composition and partially fungal community composition. Filtering‐dependent results were obtained for bacterial evenness. Buchnera phylogeny supports the hypothesis of cospeciation of primary endosymbionts in oak aphids. We detected Arsenophonus, Hamiltonella, Rickettsia, Rickettsiella, Serratia and Sphingopyxis in oak aphids, with their prevalence and abundance partially affected by pooling. Pooling leads to overestimating the frequency of multispecies endosymbiont infections, while underestimating their relative abundance. Conclusion We hereby extend our view on non‐model aphid microbiomes and identify pitfalls in experimental design in aphid microbiome research.

Plants are especially useful as biological indicators to assess air pollution and the effects of urbanisation. The aim of this study was to investigate tree species' sensitivity to air pollution using the Air Pollution Tolerance Index (APTI), the dust content (PM10) of leaves, and the heavy metal concentration of leaves. Sampling sites were in a city park (urban area), a location on the edge of the city (suburban area), and a forested location (rural area) along an urbanisation gradient in the city of Vienna in Austria. Leaf samples were collected from Acer platanoides, Fraxinus excelsior, and Quercus robur tree species. The APTI was determined by measuring the content of relative water ascorbic acid and chlorophyll, and the pH of leaf extracts. We found significant difference among species in their relative water content, pH, and content of ascorbic acid and chlorophyll Additionally, we found significant differences in chlorophyll content and pH based on sampling site. The highest chlorophyll content was found in A. platanoides. There was a significant difference among species in Al, Ba, Cr, Ni, and Zn concentrations in each stage of urbanisation. Based on APTI values, the studied species were sensitive indicators of air pollution; thus, they are useful bioindicator species, and they are suitable for air pollution monitoring. We demonstrated the effects of urbanisation with these bioindicator species with elevated PM10, Al, Ba, Cu, Fe, Sr, and Zn concentrations in urban area samples. [ABSTRACT FROM AUTHOR]

Key message: Naturally regenerating populations of common beech, pedunculate, and sessile oaks develop strong spatial genetic structures at adult and seedling stages. Significant genetic relationship occurs between individuals growing up to 60 m apart. This indicates the minimum distance separating trees from which seeds used for reforestation should be harvested to avoid the adverse effects of excessive relatedness among offspring. Context: Spatial genetic structure is an inherent characteristic of naturally regenerating plant populations and has practical implications in forests for the management of genetic resources. Aims: We investigated the extent of spatial genetic structure in three broad-leaved forest tree species (common beech—Fagus sylvatica L.; pedunculate oak—Quercus robur L.; and sessile oak—Q. petraea (Matt.) Liebl.) coexisting in the same nature reserve, explored its variation among species and different life stages (adults/offspring), and tested its possible determinants. Methods: We explored patterns of spatial distribution of individuals, and using microsatellites, we estimated parameters of spatial genetic structure based on kinship relationships, considering possible sources of variation. Results: In adults, the strongest spatial genetic structure was found for Q. petraea (Sp = 0.0187), followed by F. sylvatica (Sp = 0.0133), and the weakest in Q. robur (Sp = 0.0080). It was uniform across different age classes in pedunculate oak but decreased with age in sessile oak. No apparent relationship between age and spatial genetic structure was found in beech. Offspring exhibited significant spatial genetic structure (ranging from 0.0122 in beech to 0.0188 in sessile oak). The cohorts of seedlings having both parents present within the study site had stronger spatial genetic structures than cohorts of seedlings with only one local parent. Conclusion: Spatial genetic structure is strong in naturally regenerating populations of heavy-seeded forest trees. Pollen immigration from outside of a local forest stand can significantly decrease the extent of spatial genetic structure in offspring generations. [ABSTRACT FROM AUTHOR]

Forest ecosystems in the Republic of Moldova play a significant role in maintaining dynamic ecological balance due to their diverse protective functions. However, edifice forest species, such as oak, exhibit pronounced sensitivity to abiotic stress, considering the prolonged periods of regeneration from shoots and the on-going changes in environmental conditions, particularly heat waves and persistent droughts. Our study focused on pedunculate oak (Quercus robur), sessile oak (Q. petraea) and downy oak (Q. pubescens) trees, situated in close proximity within a stand. The research aimed to assess the responses of these species to natural thermal stress. Following exposure to natural stress characterized by high temperatures and persistent drought, we analysed their responses based on five biological indicators over an eleven-day monitoring period under controlled laboratory conditions. Pedunculate oak exhibited sensitivity to stress, as indicated by elevated catalase activity and reduced coefficients of metabolic intensity and leaf water content, whereas the relative quantum yield of photosystem II in tree leaves recorded moderate values. In contrast, downy oak adjusted its catalase activity to stressful environmental conditions, presenting coefficients of metabolic intensity and leaf water content at high values, suggesting an evolutionary adaptation of the species to arid environmental conditions. Sessile oak occupied an intermediate position in stress response according to these indicators. [ABSTRACT FROM AUTHOR]

Invasion of alien plant species entails great ecological, economic, and social consequences. One of the effective ways to manage invasive species may be to account for and destroy them using unmanned aerial vehicles. However, this requires learning to identify invasive species using real-time remote sensing. Recently, great hopes for solving this problem have been placed on hyperspectral cameras. In this regard, there is a need to fundamentally answer the question of the possibility of identifying plant species from spectral data, regardless of the time of data acquisition. The aim of the study was to identify four species of woody plants by the time series of spectral characteristics of their leaves, obtained using a hyperspectral camera. The study was conducted in laboratory conditions, in which the number of unaccounted for factors is much less than in the field. The objects of study were one native species Quercus robur L. and three species invasive for Europe – Fraxinus pennsylvanica Marsh., Ailanthus altissima (Mill.) Swingle, Parthenocissus inserta (A. Kern.) Fritsch. The collection of leaves for Hyperspectral Imaging (HSI) was carried out during the growing season of the plants at intervals of 7–10 days. Random Forest (RF) was chosen as the object classification method. The RF pixel-based test was carried out both for specific calendar dates (time slice) and for the time series when the RF model was trained on the data of one calendar date and tested on other calendar dates. None of the RF testing methods was able to classify all four species simultaneously with sufficient probability (more than 90%). Therefore, RF testing of combinations of two samples was used – "species" & "other three species" for all calendar dates. This approach made it possible to classify species by spectral characteristics of leaves with 100% reliability. It has been established that the spectral bands informative for RF pixel-based classification lie in the visible range of the spectrum in the range from 462 to 478, from 510 to 534, and from 566 to 646 nm. [ABSTRACT FROM AUTHOR]

The ontogeny of pedunculate oak (Quercus robur L.) in green moss pine forests has been studied. The authors use the concept of the biological age of plants and the idea of polyvariant development of individuals. It has been shown that 11 ontogenetic stages are distinguished in the ontogeny of oak: seeds, seedlings, juvenile individuals, immature individuals (2 subgroups), virginile individuals (2 subgroups), young generative, mature generative, old generative trees, as well as senile individuals. A detailed description of these stages is given. It was revealed that oak trees in pine forests develop individuals according three levels of vitality – reduced, low and extremely low (sublethal). Individuals with reduced vitality develop in large gaps, low vitality – in small gaps, and extremely low vitality – under the forest canopy. Oak individuals with reduced vitality, that gradually increasing their power in large gaps, become edificators of the forest community. Plants with low and sublethal vitality form a population reserve, which is represented by many depressed individuals. Their development is significantly delayed in the pregenerative period in anticipation of an improvement in the light regime. The ontogenetic stages of the oak identified in the paper can be used to analyze the demographic structure and to predict the development of its populations in plant communities.

Background. In recent centuries on the East European Plain massive degeneration of oak forests has been in progress. This is caused by a complex of climatic and anthropogenic factors. Since Quercus robur L. is a key species it seems to be necessary to research comprehensively its individuals and populations at different levels including the aspects of modern biomorphology. The purpose of the study is quantitative and structural analysis of crown organization of reproductive individuals of Q. robur within the Voroninsky nature reserve and its security zone. Materials and methods. The crowns of 335 young and middle-aged reproductive individuals in upland watershed, slope and terrace landscapes of the reserve have been analyzed. We measured meanings of morphometric parameters of individuals, determined its life forms and described a set of elements of architectural models, hierarchic to polyarchic organization plan ratio and expression of reiteration within an individual’s crown. Results. The tallest individuals of Q. robur grow in dense canopy stands on the upland watersheds. The lowest and at the same time the most spread individuals grow in the margins of oakeries and in the sparse oakeries on the slopes. In all habitats the Rauh architectural model-based individuals belonging to the one trunk life forms prevail. Besides in the studied individuals the elements of Troll, Leeuwenberg and Koriba architectural models were detected. In most individuals with aging trunk is replacing with systems of daughter axes having various growth directions. The processes of immediate reiteration contribute significantly to crowns. Conclusions. In all habitats of the Voroninsky nature reserve individuals of Q. robur reach a high level of crown plasticity when get established in middle-age reproductive ontogenetic state. Such level is realized mainly due to enhancement of polyarchic organization plan of crown. This points to the species’ wide adaptive possibilities in terms of the Western Volga upland forest-steppe.

We analysed the quantity and quality of Quercus robur L. acorns after years with a very poor yield under the canopy of natural oak stands of various compositions, ages and stock densities in the northeastern part of Ukraine. We determined the mass of 1,000 healthy and damaged acorns of the current year. The levels of variability were estimated for the number and mass of acorns under the canopy of the studied stands. The dependences of the number of acorns on the age of oak stands and their stock density were studied. The total number of acorns under the canopy of natural oak stands was 9,900–19,000 seeds per hectare with a total mass of 26.8–54.1 kg per hectare in 2020 and 8,600–17,200 seeds per hectare with a total mass of 22.7–48.4 kg per hectare in 2021. The proportion of damaged acorns was about 70% both in 2020 and 2021. The largest number of acorns was concentrated under healthy trees (without signs of decline) that had a well-developed crown and, therefore, received more sunlight and heat. The identified quantitative and qualitative estimates and acorn spreading pattern need to be considered when selecting sites for further natural seed regeneration in old-aged oak stands.

Pedunculate oak (Quercus robur L., 1753) is one of the widely distributed oak species in Europe. A large number of organisms develop on its leaves. To determine the extent to which the oak powdery mildew, oak lace bug, and other foliofagous insects affect the growth of young oak trees, three experimental fields were selected in a 10-year-old pedunculate oak stand. In each of them, 50 trees were randomly selected, and their height was measured at the beginning of the vegetative season. The first experimental field was treated with a systemic insecticide, the second with a systemic fungicide, and the third, a comparison area, with water, during the entire vegetative season. At the end of the vegetative season, 25 plants with one apical branch were selected in each experimental field. Their height was measured, and 20 leaves were taken from each plant to determine the extent of the damage on them at the end of the experiment. After processing the obtained data, it was determined that: 1. Both foliofagous insects and oak leaf inhabiting fungi affect the growth of the oak trees significantly; 2. The oak lace bug did not influence the growth of the young trees significantly, as its abundance was low in all of the experimental areas; 3. The greatest damage on the leaves was caused by defoliator insects, which is why they contributed the most to the decrease in growth caused by insects; 4. The influence of the foliofagous insects on the growth of the trees was not significantly different from the influence of fungi; 5. Suppression of oak powdery mildew and foliofagous insects on young trees is useful as it positively influences the vitality and growth of those trees, and contributes to economic and ecological gain.

The aim of this study was to obtain a better understanding on short-distance basidiospore dispersal of the wood-decay fungus Fistulina hepatica, thereby providing valuable knowledge for the conservation management of this protected species. Specifically, the study was expected to reveal site-specific patterns of basidiospore release and spread in oak stands during one fruiting season under north European conditions. The trapping of fungal spores was carried out between August and October 2022 using passive spore traps placed in three oak stands (>200-year-old) in central Lithuania. The average daily temperature was recorded throughout the period of spore trapping. Collected samples were analyzed using high-throughput sequencing of fungal ITS2 rDNA. The results showed that the relative abundance of F. hepatica reads was influenced by the time of fruitbody maturation, but not by the average daily temperature. Although there was a certain variation among different study sites, the results showed that a great majority of F. hepatica spores were deposited within 50 m from the fruitbody, showing that the fungus to a large extent is dependent on local habitats for colonization. [ABSTRACT FROM AUTHOR]

We analysed the quantity and quality of Quercus robur L. acorns after years with a very poor yield under the canopy of natural oak stands of various compositions, ages and stock densities in the northeastern part of Ukraine. We determined the mass of 1,000 healthy and damaged acorns of the current year. The levels of variability were estimated for the number and mass of acorns under the canopy of the studied stands. The dependences of the number of acorns on the age of oak stands and their stock density were studied. The total number of acorns under the canopy of natural oak stands was 9,900–19,000 seeds per hectare with a total mass of 26.8–54.1 kg per hectare in 2020 and 8,600–17,200 seeds per hectare with a total mass of 22.7–48.4 kg per hectare in 2021. The proportion of damaged acorns was about 70% both in 2020 and 2021. The largest number of acorns was concentrated under healthy trees (without signs of decline) that had a well-developed crown and, therefore, received more sunlight and heat. The identified quantitative and qualitative estimates and acorn spreading pattern need to be considered when selecting sites for further natural seed regeneration in old-aged oak stands. [ABSTRACT FROM AUTHOR]

Genetic diversity was studied in 41 populations (755 trees) of pedunculate oak Quercus robur in North Eastern Europe, the Balkans, the Crimea, and the Caucasus using 14 nuclear microsatellite loci (nSSR). To estimate the contribution of sessile oak Q. petraea to the genetic pool of Q. robur, six populations (109 trees) of Q. petraea were added to the analysis. Comparison was made with the previously obtained chloroplast DNA data. A low level of nuclear DNA introgression of Q. petraea in Q. robur was revealed. No significant influence of Q. petraea on the geographic structure of Q. robur diversity was found. High differentiation in nuclear markers between populations of Q. robur from different geographical regions and within the Caucasus was obtained. According to the results of the Bayesian clustering implemented with STRUCTURE program, the largest difference in Q. robur was observed between Caucasian populations and the populations of North Eastern Europe. This subdivision is quite consistent with the deep differences in chloroplast DNA between these regions, where no common or closely related chloroplast haplotypes have been found, and indicates an ancient age of the isolation of the Caucasus, estimated from microsatellite data using the ABC method as 3500 generations (~350 ka ago, Middle Pleistocene). In the north of Eastern Europe, according to STRUCTURE results, a weak trend from east to west was observed, in contrast to the chloroplast DNA data indicating a sharp difference between the populations of the east of the Russian Plain and Urals from the more western ones due to the absence of common haplotypes. The populations of the southeastern Balkans differed from the populations of North Eastern Europe, and the ABC estimate of divergence time (910 generations) significantly exceeded the age of the Last Glacial Maximum, which rejected the participation of southeastern region of the Balkans in the recolonization of Eastern Europe after the last glaciation. In the Caucasus, the structure of nuclear DNA generally corresponded to the phylogeography of chloroplast DNA and to the morphological data. Deep differentiation was found in nuclear DNA between western and eastern Caucasian populations, with an estimated age of divergence of 2100 generations. In the Crimea and the extreme Western Caucasus, STRUCTURE revealed a mixture of the Balkan and West Caucasian clusters, which, in combination with chloroplast DNA data, indicates their origin as a result of multiple migrations. This group of populations contains only West Caucasian and Crimean endemic chloroplast haplotypes, without the presence of Balkan haplotypes, which indicates the introgression of the genes of the Balkan cluster into the Crimean and West Caucasian populations through pollen flow, without seed transfer. The age of occurrence of this grouping was estimated at 510 generations. [ABSTRACT FROM AUTHOR]

Beneficial effects of silicon (Si) on plants have primarily been studied in crop species under single stress. Moreover, nutrient acquisition-based responses to combination of biotic and abiotic stresses (a common situation in natural habitats) have rarely been reported, in particular in conjunction with soil amendments with Si. Pedunculate oak (Quercus robur L.), one of the ecologically and economically most important tree species in Europe, is facing a severe decline due to combined stresses, but also problems in assisted regeneration in nurseries. Here, we studied the effect of Si supply on the leaf nutriome, root traits and overall growth of 12-weeks-old oak seedlings exposed to abiotic stress [low phosphorus (P) supply], biotic stress (Phytophthora plurivora root infection), and their combination. The application of Si had the strongest ameliorative effect on growth, root health and root phenome under the most severe stress conditions (i.e., combination of P deficiency and P. plurivora root infection), where it differentially affected the uptake and leaf accumulation in 11 out of 13 analysed nutrients. Silicon supply tended to reverse the pattern of change of some, but not all, leaf nutrients affected by stresses: P, boron (B) and magnesium (Mg) under P deficiency, and P, B and sulphur (S) under pathogen attack, but also nickel (Ni) and molybdenum (Mo) under all three stresses. Surprisingly, Si affected some nutrients that were not changed by a particular stress itself and decreased leaf Mg levels under all the stresses. On the other hand, pathogen attack increased leaf accumulation of Si. This exploratory work presents the complexity of nutrient crosstalk under three stresses, and opens more questions about genetic networks that control plant physiological responses. Practically, we show a potential of Si application to improve P status and root health in oak seedlings, particularly in nurseries. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Forestry Society of Croatia / Sumarski List Hrvatskoga Sumarskoga Drustva is the property of Forestry Society of Croatia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aim. The objective of this study was to identify and analyze the climatic signal contained in the tree-rings of common oak on the southeastern border of its range in Russia (Ural River basin).Material and Methods. The materials for the study were tree-rings in samples of common oak wood from three sites in the southern part of the Dziau-tyube ridge. Measurements of ring-width were performed on the MBS binocular microscope and on the Lintab measuring complex with the TSAP-WinTM software package. The construction of tree-ring chronologies was carried out in the ARSTAN program. Dendroclimatic analysis was carried out in the R package treeclim.Results. The limiting climatic factors for the radial growth of the common oak on the southeastern border of its range are precipitation during the winter-spring season and the initial period of vegetation and to the greatest extent with the precipitation in March-May. It was shown that the strength of this climatic signal in oak tree rings was not constant over time. The dynamics of this signal are characterized by the presence of local periods of decline, the beginning of which is timed to the years of mass gypsy moth outbreaks.Conclusions. Since the beginning of the 1980s, there has been a significant decrease in the relationship of radial growth with the amount of precipitation for March-May. The reason for this change, in our opinion, could be a strong change in the condition of trees and stands caused by the consistent impact of strong oak defoliation caused by Gypsy moths and late spring frosts.

There are several highly damaging Phytophthora species pathogenic to forest trees, many of which have been spread beyond their native range by the international trade of live plants and infested materials. Such introductions can be reduced through the development of better tools capable of the early, rapid, and high-throughput detection of contaminated plants. This study utilized a volatilomics approach (solid-phase microextraction coupled to gas chromatography–mass spectrometry) to differentiate between several Phytophthora species in culture and discriminate between healthy and Phytophthora-inoculated European beech and pedunculate oak trees. We tentatively identified 14 compounds that could differentiate eight Phytophthora species from each other in vitro. All of the Phytophthora species examined, except Phytophthora cambivora, uniquely produced at least one compound not observed in the other species; however, most detected compounds were shared between multiple species. Phytophthora polonica had the most unique compounds and was the least similar of all the species examined. The inoculated seedlings had qualitatively different volatile profiles and could be distinguished from the healthy controls by the presence of isokaurene, anisole, and a mix of three unknown compounds. This study supports the notion that volatiles are suitable for screening plant material, detecting tree pathogens, and differentiating between healthy and diseased material.

The spread of neophytes (non-native plant species) challenges the conservation status and ecological integrity of forests, especially in lowland areas. Long-term resurvey studies are needed to evaluate the temporal dynamics of neophytes in forests; however, such data are scarce. In 2023, we resampled a set of 45 permanent vegetation plots (established in 1992/93) in two forest vegetation types: oak–hornbeam forests dominated by Quercus robur and colline oak–beech forests dominated by Q. petraea. Over the last 30 years, oak forests have experienced extensive oak tree mortality, with the degree of habitat degradation being greater in Q. robur forests. In the early 1990s, only three neophytes with low abundance were recorded across all plots. In the 2023 resurvey, the total number of neophytes increased to 22 species (15 herbaceous and 7 woody species), comprising 6.9% of the total species pool in the understory layer. The increase in the plot-level number and cover of neophytes was significant in plots dominated by Q. robur but not in those with Q. petraea. The most frequent neophytes were Impatiens parviflora (present in 31% of plots), Solidago gigantea (27%), Erigeron annuus (16%) and Erechtites hieraciifolia (16%). The richness and cover of neophytes were significantly affected by the tree layer cover (negative correlation) and the degree of soil disturbance (positive correlation). All neophytes established in disturbed patches, whereas the occurrence of I. parviflora was exceptional as it was able to colonize less degraded, shaded understory environments. Habitat degradation (the mortality-induced loss of stand-forming oak trees resulting in extensive tree layer cover decrease) emerged as a key driver promoting neophyte proliferation, coupled with the impact of management-induced disturbances affecting overstory and soil conditions. The spread is expected to continue or even intensify in the future because novel light regimes and disturbances make forest habitats less resistant to neophyte proliferation.

It is often suggested to release oaks (Quercus robur) from competition, to ensure their survival and boost their conservational value. However, few studies have explored how long‐lasting this effect is and how it affects saproxylic beetles.Ten years after cutting, we investigated effects of different release cutting levels (high, medium, and no release) around 140‐year‐old retained oaks in a commercial forest with Norway spruce (Picea abies).We evaluated oak vitality using crown and dead wood measurements. Saproxylic beetles were caught in window traps, identified to species level, and grouped according to their association with oak and/or Norway spruce.Released oaks had more light, higher temperatures, greater crown growth, and less dead wood in the crown compared to the no‐release control.After 10 years we still found a higher abundance of oak‐associated beetles and higher overall species richness of saproxylic beetles in the released oaks. Beetle species composition significantly differed between released oaks and control.We suggest avoiding planting trees beneath retained oaks when regenerating conifer forests and to proceed with conservation management during subsequent thinning by removing regeneration under the oak crowns. We emphasize the benefits of monitoring the retained oaks to maintain tree vitality, habitat quality, and insolation. [ABSTRACT FROM AUTHOR]

The quality of container-grown seedlings is influenced by the air and water properties of the substrate. These properties are closely tied to the amount and frequency of water supplied through sprinkler systems in nurseries, as well as the density of the substrate in the container cells. Throughout the entire growing season, this study examined how various parameters of Scots pine, Norway spruce, European beech, and pedunculate oak seedlings cultivated in HIKO V120SS and V265 containers were affected by two factors. Firstly, the study analyzed the impact of increased substrate density when filling the containers. Secondly, it explored the precise dosing of water applied by the sprinkler system, which was determined based on substrate sensors and meteorological conditions surrounding the seedlings. The results revealed that increased substrate compaction led to a long-term reduction in air capacity and an increase in water capacity within pine, spruce, and beech containers. However, oak seedlings were not affected by the increased substrate density. Additionally, the higher density of the compacted substrate positively influenced the growth parameters of pine seedlings but did not affect the other species. As a result, the current substrate compaction level used in the nursery where the measurements were taken appears to be optimal for spruce, beech, and oak seedlings. Furthermore, precise control over the amount of water applied during irrigation allowed for a reduction in water consumption by about 8%. This control also resulted in improved seedling sturdiness quotient and a more developed root system in the case of pine seedlings. However, no significant differences were observed for the other species. [ABSTRACT FROM AUTHOR]

Chloroplast DNA variability was examined in 872 trees of pedunculate oak (Q. robur L.), sessile oak (Q. petraea (Matt.) Liebl.) and downy oak (Q. pubescens Willd.) on the Crimean Peninsula, in the Western Caucasus and in the Balkan region in order to study phylogeography and interaction of these species in the Black Sea region. Sequencing of five fragments with a total length of more than 10,000 base pairs revealed 12 haplotypes of chloroplast DNA. For the haplotype typing in the studied populations, chloroplast microsatellites (cpSSR), sequencing, and restriction analysis were used. Haplotypes detected belong to several divergent phylogenetic lineages. The studied species almost do not differ from each other in the composition of haplotypes and the geographical structure of variability, which demonstrates a certain level of gene flow between them in mixed populations. The haplotypes of the Balkan region are closely related to the haplotypes of previously studied populations from Eastern Europe and the western part of the Russian Plain, and are not found in the Crimea and the Caucasus. On the Crimean Peninsula, two geographical groups of populations are distinguished, which differ sharply in the composition of haplotypes. The difference between the western part of the peninsula and the eastern part is shown, which suggests a multiple origin of oak populations in the Crimea as a result of migrations from two sources, which could be facilitated by fluctuations in the Black Sea level and its desalination, which repeatedly occurred in the Pleistocene and Holocene. The predominance of two divergent haplotypes in the western part of the peninsula, similar to the haplotypes of Asia Minor, indicates the penetration of oak from this region and the presence of an isolated refugium in the mountainous forest regions of Crimea during the last glacial maximum. At the same time, haplotypes common with the Western Caucasus are spread in the east of the mountain-forest part of the Eastern Crimea. The sharp boundary between the areas of distribution of "western" and "eastern" haplotypes in the Eastern Crimea indicates a relatively recent time of the formation of a secondary contact zone between local and Caucasian oak populations as a result of postglacial colonization. [ABSTRACT FROM AUTHOR]

Soil standing may be studied indirectly using remote sensing through an assessment of state of the plants growing on it. The ability to evaluate the physiological state of plants using the hyperspectral survey data also provides a tool to characterize vegetation cover and individual samples of woody plants. In the present work the hyperspectral imaging was applied to identify the species of the woody plants evaluating the differences in their physiological state. Samples of Quercus macrocarpa Michx., Q. robur L. and Q. rubra L. were studied using Cubert UHD-185 hyperspectral camera over five periods with an interval of 7-10 days. In total, 80 vegetation indices (VIs) were calculated. Sample sets of values of VIs were analyzed using analysis of variance (ANOVA), principal component analysis (PCA), decision tree (DT), random forest (RF) methods. It was shown using the ANOVA, that the following VIs are the most dependent on the species affiliation of the samples: Carter2, Carter3, Carter4, CI, CI2, CRI4, Datt, Datt2, GMI2, Maccioni, mSR2, MTCI, NDVI2, OSAVI2, PRI, REP_Li, SR1, SR2, SR6, Vogelmann, Vogelmann2, Vogelmann4. VIs that are effective for the separation of oak species, were also revealed using the DT method – these are Boochs, Boochs2, CARI, CRI1, CRI3, D1, D2, Datt, Datt3; Datt4, Datt5, DD, DDn, EGFN, Gitelson, MCARI2, MTCI, MTVI, NDVI3, PRI, PSND, PSRI, RDVI, REP_Li, SPVI, SR4, Vogelmann, Vogelmann2, Vogelmann3. PCA and RF methods reliably differentiated Q. rubra from Q. robur and Q. macrocarpa. Q. rubra, unlike other species, was under stress from the impact of soil pH against the background of drought. This was manifested in leaf chlorosis. Influence of the environmental stress factors on the reliability and efficiency of species identification was demonstrated. Q. robur and Q. macrocarpawere were poorly separated by PCA and RF methods all over the five periods of the experiment.

The present study was inspired by scientific reports describing the positive effects of silicon preparations on fruit and vegetables in horticulture. The use of silicon preparations in forest protection represents a new research application, especially in the cases of oak seedlings that are damaged by oak powdery mildew. Additionally, these preparations increase the photosynthetic efficiency of the seedlings, and thus promote increased biomass and better nutritional value of the root systems. The new idea of using silicon formulations in forestry, based on the initial test results, is particularly important for seedlings in the post-planting period in forest plantations. In particular, these preparations increase yield and plant growth, and improve plant health. So far, no comparable studies have been conducted on forest tree species. To this end, one year-old pine (Pinus sylvestris L.) and two year-old English oak (Quercus robur L.) seedlings were sprayed with silicon preparations of different concentrations, and changes in growth parameters and photosynthetic efficiency were observed. The main objective of the study was to determine the effect of the silicon preparation on the seedlings during their first life span, i.e., the first year after planting. In this study, 50 pine and 50 oak seedlings were sprayed three times with the silicon preparation, in five variants (control; concentrations of 1%, 2%, 3% and 5%), as well as the chlorophyll fluorescence, height, thickness and biomass of the roots, were measured. It was found that the treatment with a concentration of 2% was better and statistically, significantly different from the other variants, e.g., in terms of increasing photosynthetic efficiency. [ABSTRACT FROM AUTHOR]

Beneficial effects of silicon (Si) on plants have primarily been studied in crop species under single stress. Moreover, nutrient acquisition-based responses to combination of biotic and abiotic stresses (a common situation in natural habitats) have rarely been reported, in particular in conjunction with soil amendments with Si. Pedunculate oak (Quercus robur L.), one of the ecologically and economically most important tree species in Europe, is facing a severe decline due to combined stresses, but also problems in assisted regeneration in nurseries. Here, we studied the effect of Si supply on the leaf nutriome, root traits and overall growth of 12-weeks-old oak seedlings exposed to abiotic stress [low phosphorus (P) supply], biotic stress (Phytophthora plurivora root infection), and their combination. The application of Si had the strongest ameliorative effect on growth, root health and root phenome under the most severe stress conditions (i.e., combination of P deficiency and P. plurivora root infection), where it differentially affected the uptake and leaf accumulation in 11 out of 13 analysed nutrients. Silicon supply tended to reverse the pattern of change of some, but not all, leaf nutrients affected by stresses: P, boron (B) and magnesium (Mg) under P deficiency, and P, B and sulphur (S) under pathogen attack, but also nickel (Ni) and molybdenum (Mo) under all three stresses. Surprisingly, Si affected some nutrients that were not changed by a particular stress itself and decreased leaf Mg levels under all the stresses. On the other hand, pathogen attack increased leaf accumulation of Si. This exploratory work presents the complexity of nutrient crosstalk under three stresses, and opens more questions about genetic networks that control plant physiological responses. Practically, we show a potential of Si application to improve P status and root health in oak seedlings, particularly in nurseries.

The paper describes the individual development (ontogeny) of the pedunculate oak (Quercus robur L.) in the floodplain meadows under the conditions of free growth. The authors use the concept of the biological age of plants, developed by Russian scientists. Eleven ontogenetic states are distinguished in the development of the oak: seeds, seedlings, juvenile individuals, immature individuals (2 subgroups), virginile individuals (2 subgroups), young generative, mature generative, old generative trees, as well as senile individuals. A detailed description of these stages is given. The ontogenetic stages are allocated on the basis of a set of qualitative and quantitative traits of plants. The paper shows that the main coenotic role of the seed stage is dispersing the population; seedling stage – growing in a community; juvenile – adapting to growth in the ground layer; immature – adapting to the undergrowth layer; virginile – adapting to the second layer of the tree stand; generative trees – creating a coenotic environment and seed production; and senile trees – gradually releasing additional resources (light, space, etc.) for the coming generation of trees. The ontogenetic stages of the oak identified in the paper can be used to analyze the demographic structure and to predict the development of its populations in plant communities.

Modeling diameter distribution is a crucial aspect of forest management, requiring the selection of an appropriate probability density function or cumulative distribution function along with a fitting method. This study compared the suitability of eight probability density functions—A Charlier, beta, generalized beta, gamma, Gumbel, Johnson’s SB, and Weibull (two- and three-parameter)—fitted using both derivative methods (Moments) fitted in SAS/STATTM and optimization methods (MLE) fitted with the ‘optim’ function in R for diameter distribution estimation in forest stands. The A Charlier and Gumbel functions were used for the first time in this type of comparison. The data were derived from 167 permanent sample plots in an Atlantic forest (Quercus robur) and 59 temporary sample plots in tropical forests (Tectona grandis). Fit quality was assessed using various indices, including Kolmogorov–Smirnov, Cramér–von Mises, mean absolute error, bias, and mean squared error. The results indicated that Johnson’s SB function was more suitable for describing the diameter distribution of the stands. Johnson’s SB, three-parameter Weibull, and generalized beta consistently performed well across different fitting methods, while the fits produced by gamma, Gumbel, and two-parameter Weibull were of poor quality.

The micromorphology of the leaf epidermis, localization, and silicon content in the epidermal cells of Quercus robur leaves growing in the shade and under direct sunlight in the Feofaniya Park (Kyiv, Ukraine) were studied using scanning electron microscopy and laser confocal microscopy. Silicon inclusions were found in the anticlinal and periclinal walls of adaxial epidermal cells, trichomes, guard cells of stomata, and walls of regular epidermal cells on the abaxial leaf surface, the amount of which varied according to the conditions of growth. Natural shading and the intensity of solar irradiation were found affecting the size of leaf blades, the ultrastructure of the leaf epidermis, and changes in the silicon content of oak leaves. Studies have shown that the anticlinal walls of the adaxial epidermis and the trichomes and stomata of the abaxial epidermis of leaves are the main silicon accumulators. The findings suggest that changes in leaf microstructure and silicon content contribute to maintaining optimal water balance in plants and can be regarded as signs of phenotypic plasticity in plants and an adaptive marker depending on the sunlight conditions of oak growth.

Quercus robur and Q. petraea are, in addition to Fagus sylvatica, the main economically used deciduous tree species in Europe. Identification of these two species is crucial because they differ in their ecological demands. Because of a changing climate, foresters must know more than ever which species will perform better under given environmental conditions. The search for differentiating molecular markers between these two species has already lasted for decades. Until now, differentiation has only been possible in approaches with a combination of several molecular markers and a subsequent statistical analysis to calculate the probability of being one or the other species. Here, we used MiSeq Illumina data from pools of Q. robur and Q. petraea specimens and identified nuclear SNPs and small InDels versus the Q. robur reference genome. Selected sequence variants with 100% allele frequency difference between the two pools were further validated in an extended set of Q. robur and Q. petraea specimens, and then the number of markers was deliberately reduced to the smallest possible set for species differentiation. A combination of six markers from four nuclear regions is enough to identify Q. robur, Q. petraea or hybrids between these two species quite well and represents a marker set that is cost-efficient and useable in every laboratory. [ABSTRACT FROM AUTHOR]

Nursery cultivation practices can be modified to increase resistance to water stress in forest seedlings following field establishment, which may be increasingly important under climate change. We evaluated the morphological (survival, growth) and physiological (chlorophyll fluorescence, leaf water potential) responses to water stress for three ecologically diverse Quercus species (Q. robur, Q. pubescens, and Q. ilex) with varying traits resulting from the combination of growing media (peat, coir) and fertilization (standard, P-enriched, K-enriched). For all species under water stress, seedlings grown in coir had generally higher growth than those grown in peat. Seedlings fertilized with P performed better, particularly for survival; conversely, K fertilization resulted in inconsistent findings. Such results could be explained by a combination of factors. P fertilization resulted in higher P accumulation in seedlings, while no K accumulation was observed in K fertilized seedlings. As expected, the more drought-sensitive species, Q. robur, showed the worst response, while Q. pubescens had a drought resistance equal or better to Q. ilex despite being classified as intermediate in drought resistance in Mediterranean environments. [ABSTRACT FROM AUTHOR]

Soil standing may be studied indirectly using remote sensing through an assessment of state of the plants growing on it. The ability to evaluate the physiological state of plants using the hyperspectral survey data also provides a tool to characterize vegetation cover and individual samples of woody plants. In the present work the hyperspectral imaging was applied to identify the species of the woody plants evaluating the differences in their physiological state. Samples of Quercus macrocarpa Michx., Q. robur L. and Q. rubra L. were studied using Cubert UHD-185 hyperspectral camera over five periods with an interval of 7-10 days. In total, 80 vegetation indices (VIs) were calculated. Sample sets of values of VIs were analyzed using analysis of variance (ANOVA), principal component analysis (PCA), decision tree (DT), random forest (RF) methods. It was shown using the ANOVA, that the following VIs are the most dependent on the species affiliation of the samples: Carter2, Carter3, Carter4, CI, CI2, CRI4, Datt, Datt2, GMI2, Maccioni, mSR2, MTCI, NDVI2, OSAVI2, PRI, REP_Li, SR1, SR2, SR6, Vogelmann, Vogelmann2, Vogelmann4. VIs that are effective for the separation of oak species, were also revealed using the DT method – these are Boochs, Boochs2, CARI, CRI1, CRI3, D1, D2, Datt, Datt3; Datt4, Datt5, DD, DDn, EGFN, Gitelson, MCARI2, MTCI, MTVI, NDVI3, PRI, PSND, PSRI, RDVI, REP_Li, SPVI, SR4, Vogelmann, Vogelmann2, Vogelmann3. PCA and RF methods reliably differentiated Q. rubra from Q. robur and Q. macrocarpa. Q. rubra, unlike other species, was under stress from the impact of soil pH against the background of drought. This was manifested in leaf chlorosis. Influence of the environmental stress factors on the reliability and efficiency of species identification was demonstrated. Q. robur and Q. macrocarpawere were poorly separated by PCA and RF methods all over the five periods of the experiment. [ABSTRACT FROM AUTHOR]

The variability of five fragments of chloroplast DNA (ASq, CDq, TFq, trnH-psbA, and trnK-matK) with a total length of more than 10 000 bp in three species of roburoid oaks of the Crimean-Caucasian region (Q. robur, Q. petraea, and Q. pubescens) has been studied. A total of 11 haplotypes were found in 290 individuals from 20 populations, ten of which differed from the haplotypes of the main range. The results show a pronounced structure of the geographical distribution of haplotypes in roburoid oaks in the Crimea and the Caucasus, and the chloroplast haplotypes of the region belong to several divergent phylogenetic lineages. A comparison with data from other studies was carried out, with an assessment of the degree of effectiveness of using various chloroplast fragments and markers. The isolated phylogenetic position of the haplotypes from the Crimean-Caucasian populations and deep differences from the haplotypes of the main area allow us to conclude that roburoid oaks have historically been isolated for a long time in the Caucasus and Crimea. At the same time, the presence of common haplotypes indicates closer historical ties between the Crimean-Caucasian populations with Asia Minor and the Balkans. All haplotypes are identified by three fragments (ASq, CDq, and TFq), with a sufficient level of variability and suitable for solving problems of oak phylogeography in the Crimean-Caucasian region. The trnH-psbA and trnK-matK markers had a low level of variability and did not reveal additional haplotypes. Optimized genotyping options have been proposed, including both stepwise sequencing and a combination of analysis of chloroplast DNA microsatellite loci (cpSSR), restriction analysis (PCR-RFLP), and sequencing. To assess the variability of markers in a larger taxonomic range, representatives of other sections of the genus Quercus were included in the analysis. It was shown that the oak-specific primers proposed for ASq, CDq, and TFq fragments are suitable for species of other sections. [ABSTRACT FROM AUTHOR]

Copyright of Plant Introduction / Ìntrodukcìâ Roslin is the property of M.M. Gryshko National Botanical Garden of the NAS of Ukraine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aim: Leaves support a large diversity of fungi, which are known to cause plant diseases, induce plant defences or influence leaf senescence and decomposition. To advance our understanding of how foliar fungal communities are structured and assembled, we assessed to what extent leaf flush and latitude can explain the within‐ and among‐tree variation in foliar fungal communities. Location: A latitudinal gradient spanning c. 20 degrees in latitude in Europe. Taxa: The foliar fungal community associated with a foundation tree species, the pedunculate oak Quercus robur. Methods: We examined the main and interactive effects of leaf flush and latitude on the foliar fungal community by sampling 20 populations of the pedunculate oak Quercus robur across the tree's range. We used the ITS region as a target for characterization of fungal communities using DNA metabarcoding. Results: Species composition, but not species richness, differed between leaf flushes. Across the latitudinal gradient, species richness was highest in the central part of the oak's distributional range, and foliar fungal community composition shifted along the latitudinal gradient. Among fungal guilds, the relative abundance of plant pathogens and mycoparasites was lower on the first leaf flush, and the relative abundance of plant pathogens and saprotrophs decreased with latitude. Conclusions: Changes in community composition between leaf flushes and along the latitudinal gradient were mostly a result of species turnover. Overall, our findings demonstrate that leaf flush and latitude explain 5%–22% of the small‐ and large‐scale spatial variation in the foliar fungal community on a foundation tree within the temperate region. Using space‐for‐time substitution, we expect that foliar fungal community structure will change with climate warming, with an increase in the abundance of plant pathogens and mycoparasites at higher latitudes, with major consequences for plant health, species interactions and ecosystem dynamics. [ABSTRACT FROM AUTHOR]

Volatile organic compounds are species of concern for indoor air quality. They are emitted from a wide range of indoor sources and in particular from construction materials. Industrialized wood-based panels made from various types of wood bonded with thermosetting adhesive resins have been shown to emit volatile organic compounds over months or even years mostly due to the petrochemical binders. Some studies have been conducted on binderless panels, but they mainly focused on the pressing parameters to be applied to optimize the panel characteristics. The aim of this research is to document the emissions from binderless panels and to access the volatile composition of wood processing through the molding of materials. For this purpose, binderless boards were manufactured from hardwoods, known to emit less than softwoods with different thermopressing temperatures and times. Emissions were studied by placing the materials in microchambers. Volatile organic compounds were then sampled and analyzed by various chromatographic methods. On the other hand, materials were pyrolyzed and then analyzed by gas chromatography and mass spectrometry. The implemented protocols proved suitable for the determination of more than 40 organic compounds, among which are aldehydes, aromatics, furans and derivatives, and carboxylic acids. [ABSTRACT FROM AUTHOR]

This work is focused on the production of transgenic tobacco plants overexpressing the oak dehydrin gene AY607707.1. Transgenic tobacco plants were generated via Agrobacterium-mediated transformation. The T-DNA of the plant transformation vector pMK contained the dehydrin gene fused to the constitutive double dCaMV35S promoter and the selectable neomycin phosphotransferase gene. The sequence of the dehydrin gene was isolated from Quercus robur by PCR approach and cloned. The constructed binary vector pMK was introduced into Agrobacterium tumefaciens LBA4404 and used in the transformation experiments. Transgenic plants were generated with an efficiency of 32.7%. PCR analyses confirmed the transgenic nature of regenerated T0 plants. The expression of the oak dehydrin gene was proved by RT-PCR and quantified by qPCR analyses. [ABSTRACT FROM AUTHOR]