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1.
Sci Rep ; 14(1): 15862, 2024 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-38982094

RESUMO

Acquiring phenological event data is crucial for studying the impacts of climate change on forest dynamics and assessing the risks associated with the early onset of young leaves. Large-scale mapping of forest phenological timing using Earth observation (EO) data could enhance our understanding of these processes through an added spatial component. However, translating traditional ground-based phenological observations into reliable ground truthing for training and validating EO mapping applications remains challenging. This study explored the feasibility of predicting high-resolution phenological phase data for European beech (Fagus sylvatica) using unoccupied aerial vehicle (UAV)-based multispectral indices and machine learning. Employing a comprehensive feature selection process, we identified the most effective sensors, vegetation indices, training data partitions, and machine learning models for phenological phase prediction. The model that performed best and generalized well across various sites utilized Green Chromatic Coordinate (GCC) and Generalized Additive Model (GAM) boosting. The GCC training data, derived from the radiometrically calibrated visual bands of a multispectral sensor, were predicted using uncalibrated RGB sensor data. The final GCC/GAM boosting model demonstrated capability in predicting phenological phases on unseen datasets within a root mean squared error threshold of 0.5. This research highlights the potential interoperability among common UAV-mounted sensors, particularly the utility of readily available, low-cost RGB sensors. However, considerable limitations were observed with indices that implement the near-infrared band due to oversaturation. Future work will focus on adapting models to better align with the ICP Forests phenological flushing stages.


Assuntos
Fagus , Aprendizado de Máquina , Estações do Ano , Mudança Climática , Florestas , Dispositivos Aéreos não Tripulados , Folhas de Planta
2.
Ecol Lett ; 27(7): e14474, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38994849

RESUMO

Spatial synchrony may be tail-dependent, meaning it is stronger for peaks rather than troughs, or vice versa. High interannual variation in seed production in perennial plants, called masting, can be synchronized at subcontinental scales, triggering extensive resource pulses or famines. We used data from 99 populations of European beech (Fagus sylvatica) to examine whether masting synchrony differs between mast peaks and years of seed scarcity. Our results revealed that seed scarcity occurs simultaneously across the majority of the species range, extending to populations separated by distances up to 1800 km. Mast peaks were spatially synchronized at distances up to 1000 km and synchrony was geographically concentrated in northeastern Europe. Extensive synchrony in the masting lower tail means that famines caused by beech seed scarcity are amplified by their extensive spatial synchrony, with diverse consequences for food web functioning and climate change biology.


Assuntos
Fagus , Sementes , Fagus/fisiologia , Sementes/fisiologia , Europa (Continente) , Mudança Climática
3.
Sci Rep ; 14(1): 13925, 2024 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-38886510

RESUMO

Recent advances in wood treatment include the use of eco-friendly coatings to improve the wood's dimensional stability and appearance. Assessing coating performance during its service life is critical for establishing a knowledge base for product optimization. Numerous approaches, including microimaging, are available for analyzing coating behavior. In addition to conventional microscopic techniques, high-resolution X-ray microtomography is a tool that provides nondestructive imaging of coatings and their substrates. In this study, we performed two-dimensional (2D) and three-dimensional (3D) visualization of tomographic reconstruction images of two coating types, spray and brush, to observe and assess the distribution of several commercial Japanese coating materials in Fagus crenata. X-ray images and plot profiles were used to determine the penetration depths and thicknesses of coatings. Each coated sample was scanned using X-ray microtomography, which allowed successful visualization and quantification of the coating penetration depth. Chemical content and concentration of the coating materials influenced penetration depth and amount.


Assuntos
Fagus , Madeira , Microtomografia por Raio-X , Microtomografia por Raio-X/métodos , Madeira/química , Fagus/química , Imageamento Tridimensional/métodos
4.
Sci Total Environ ; 941: 173665, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-38823720

RESUMO

Recent hot droughts have caused tree vitality decline and increased mortality in many forest regions on earth. Most of Central Europe's important timber species have suffered from the extreme 2018/2019 hot drought, confronting foresters with difficult questions about the choice of more drought- and heat-resistant tree species. We compared the growth dynamics of European beech, sessile oak, Scots pine and Douglas fir in a warmer and a cooler lowland region of Germany to explore the adaptive potential of the four species to climate warming (24 forest stands). The basal area increment (BAI) of the two conifers has declined since about 1990-2010 in both regions, and that of beech in the warmer region, while oak showed positive BAI trends. A 2 °C difference in mean temperatures and a higher frequency of hot days (temperature maximum >30 °C) resulted in greater sensitivity to a negative climatic water balance in beech and oak, and elevated sensitivity to summer heat in Douglas fir and pine. This suggests to include hot days in climate-growth analyses. Negative pointer years were closely related to dry years. Nevertheless, all species showed growth recovery within one to three years. We conclude that all four species are sensitive to a deteriorating climatic water balance and hot temperatures, and have so far not been able to successfully acclimate to the warmer climate, with especially Douglas and beech, but also Scots pine, being vulnerable to a warming and drying climate.


Assuntos
Mudança Climática , Florestas , Árvores , Árvores/crescimento & desenvolvimento , Alemanha , Secas , Fagus/crescimento & desenvolvimento , Quercus/crescimento & desenvolvimento , Europa (Continente)
5.
Ecol Lett ; 27(6): e14460, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38877759

RESUMO

Mast seeding is a well-documented phenomenon across diverse forest ecosystems. While its effect on aboveground food webs has been thoroughly studied, how it impacts the soil fungi that drive soil carbon and nutrient cycling has not yet been explored. To evaluate the relationship between mast seeding and fungal resource availability, we paired a Swiss 29-year fungal sporocarp census with contemporaneous seed production for European beech (Fagus sylvatica L.). On average, mast seeding was associated with a 55% reduction in sporocarp production and a compositional community shift towards drought-tolerant taxa across both ectomycorrhizal and saprotrophic guilds. Among ectomycorrhizal fungi, traits associated with carbon cost did not explain species' sensitivity to seed production. Together, our results support a novel hypothesis that mast seeding limits annual resource availability and reproductive investment in soil fungi, creating an ecosystem 'rhythm' to forest processes that is synchronized above- and belowground.


Assuntos
Fagus , Micorrizas , Fagus/microbiologia , Micorrizas/fisiologia , Biodiversidade , Microbiologia do Solo , Sementes/microbiologia , Suíça , Fungos/fisiologia , Micobioma
6.
Microb Ecol ; 87(1): 86, 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38940921

RESUMO

Forest management influences the occurrence of tree species, the organic matter input to the soil decomposer system, and hence, it can alter soil microbial community and key ecosystem functions it performs. In this study, we compared the potential effect of different forest management, coppice and high forest, on soil microbial functional diversity, enzyme activities and chemical-physical soil properties in two forests, turkey oak and beech, during summer and autumn. We hypothesized that coppicing influences soil microbial functional diversity with an overall decrease. Contrary to our hypothesis, in summer, the functional diversity of soil microbial community was higher in both coppice forests, suggesting a resilience response of the microbial communities in the soil after tree cutting, which occurred 15-20 years ago. In beech forest under coppice management, a higher content of soil organic matter (but also of soil recalcitrant and stable organic carbon) compared to high forest can explain the higher soil microbial functional diversity and metabolic activity. In turkey oak forest, although differences in functional diversity of soil microbial community between management were observed, for the other investigated parameters, the differences were mainly linked to seasonality. The findings highlight that the soil organic matter preservation depends on the type of forest, but the soil microbial community was able to recover after about 15 years from coppice intervention in both forest ecosystems. Thus, the type of management implemented in these forest ecosystems, not negatively affecting soil organic matter pool, preserving microbial community and potentially soil ecological functions, is sustainable in a scenario of climate change.


Assuntos
Fagus , Florestas , Microbiota , Quercus , Estações do Ano , Microbiologia do Solo , Solo , Fagus/microbiologia , Quercus/microbiologia , Solo/química , Bactérias/classificação , Bactérias/metabolismo , Bactérias/genética , Bactérias/isolamento & purificação , Biodiversidade , Agricultura Florestal , Árvores/microbiologia , Ecossistema
7.
Glob Chang Biol ; 30(5): e17307, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38709196

RESUMO

Climate change effects on tree reproduction are poorly understood, even though the resilience of populations relies on sufficient regeneration to balance increasing rates of mortality. Forest-forming tree species often mast, i.e. reproduce through synchronised year-to-year variation in seed production, which improves pollination and reduces seed predation. Recent observations in European beech show, however, that current climate change can dampen interannual variation and synchrony of seed production and that this masting breakdown drastically reduces the viability of seed crops. Importantly, it is unclear under which conditions masting breakdown occurs and how widespread breakdown is in this pan-European species. Here, we analysed 50 long-term datasets of population-level seed production, sampled across the distribution of European beech, and identified increasing summer temperatures as the general driver of masting breakdown. Specifically, increases in site-specific mean maximum temperatures during June and July were observed across most of the species range, while the interannual variability of population-level seed production (CVp) decreased. The declines in CVp were greatest, where temperatures increased most rapidly. Additionally, the occurrence of crop failures and low seed years has decreased during the last four decades, signalling altered starvation effects of masting on seed predators. Notably, CVp did not vary among sites according to site mean summer temperature. Instead, masting breakdown occurs in response to warming local temperatures (i.e. increasing relative temperatures), such that the risk is not restricted to populations growing in warm average conditions. As lowered CVp can reduce viable seed production despite the overall increase in seed count, our results warn that a covert mechanism is underway that may hinder the regeneration potential of European beech under climate change, with great potential to alter forest functioning and community dynamics.


Assuntos
Mudança Climática , Fagus , Estações do Ano , Temperatura , Fagus/crescimento & desenvolvimento , Fagus/fisiologia , Europa (Continente) , Sementes/crescimento & desenvolvimento , Sementes/fisiologia , Reprodução , Árvores/crescimento & desenvolvimento , Árvores/fisiologia , Polinização
8.
Rapid Commun Mass Spectrom ; 38(14): e9716, 2024 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-38738638

RESUMO

RATIONALE: This study overcomes traditional biomass analysis limitations by introducing a pioneering matrix-free laser desorption/ionization (LDI) approach in mass spectrometry imaging (MSI) for efficient lignin evaluation in wood. The innovative acetic acid-peracetic acid (APA) treatment significantly enhances lignin detection, enabling high-throughput, on-site analysis. METHODS: Wood slices, softwood from a conifer tree (Japanese cypress) and hardwood from a broadleaf tree (Japanese beech), were analyzed using MSI with a Fourier transform ion cyclotron resonance mass spectrometer. The developed APA treatment demonstrated effectiveness for MSI analysis of biomass. RESULTS: Our imaging technique successfully distinguishes between earlywood and latewood and enables the distinct visualization of lignin in these and other wood tissues, such as the radial parenchyma. This approach reveals significant contrasts in MSI. It has identified intense ions from ß-O-4-type lignin, specifically in the radial parenchyma of hardwood, highlighting the method's precision and utility in wood tissue analysis. CONCLUSIONS: The benefits of matrix-free LDI include reduced peak overlap, consistent sample quality, preservation of natural sample properties, enhanced analytical accuracy, and reduced operational costs. This innovative approach is poised to become a standard method for rapid and precise biomass evaluation and has important applications in environmental research and sustainable resource management and is crucial for the effective management of diverse biomass, paving the way towards a sustainable, circular society.


Assuntos
Biomassa , Lignina , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Madeira , Madeira/química , Lignina/análise , Lignina/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Fagus/química
9.
PLoS One ; 19(5): e0302528, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38753717

RESUMO

The analysis of critical states during fracture of wood materials is crucial for wood building safety monitoring, wood processing, etc. In this paper, beech and camphor pine are selected as the research objects, and the acoustic emission signals during the fracture process of the specimens are analyzed by three-point bending load experiments. On the one hand, the critical state interval of a complex acoustic emission signal system is determined by selecting characteristic parameters in the natural time domain. On the other hand, an improved method of b_value analysis in the natural time domain is proposed based on the characteristics of the acoustic emission signal. The K-value, which represents the beginning of the critical state of a complex acoustic emission signal system, is further defined by the improved method of b_value in the natural time domain. For beech, the analysis of critical state time based on characteristic parameters can predict the "collapse" time 8.01 s in advance, while for camphor pines, 3.74 s in advance. K-value can be analyzed at least 3 s in advance of the system "crash" time for beech and 4 s in advance of the system "crash" time for camphor pine. The results show that compared with traditional time-domain acoustic emission signal analysis, natural time-domain acoustic emission signal analysis can discover more available feature information to characterize the state of the signal. Both the characteristic parameters and Natural_Time_b_value analysis in the natural time domain can effectively characterize the time when the complex acoustic emission signal system enters the critical state. Critical state analysis can provide new ideas for wood health monitoring and complex signal processing, etc.


Assuntos
Acústica , Madeira , Madeira/química , Fagus , Pinus
10.
BMC Plant Biol ; 24(1): 377, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38714916

RESUMO

BACKGROUND: European beech (Fagus sylvatica L.) trees produce seeds irregularly; therefore, it is necessary to store beech seeds for forestation. Despite the acquisition of desiccation tolerance during development, beech seeds are classified as intermediate because they lose viability during long-term storage faster than typical orthodox seeds. In this study, beech seeds stored for short (3 years) or long (20 years) periods under optimal conditions and displaying 92 and 30% germination capacity, respectively, were compared. RESULTS: Aged seeds displayed increased membrane damage, manifested as electrolyte leakage and lipid peroxidation levels. Analyses have been based on embryonic axes, which contained higher levels of reactive oxygen species (ROS) and higher levels of protein-bound methionine sulfoxide (MetO) in aged seeds. Using label-free quantitative proteomics, 3,949 proteins were identified, of which 2,442 were reliably quantified pointing to 24 more abundant proteins and 35 less abundant proteins in beech seeds under long-term storage conditions. Functional analyses based on gene ontology annotations revealed that nucleic acid binding activity (molecular function), ribosome organization or biogenesis and transmembrane transport (cellular processes), translational proteins (protein class) and membranous anatomical entities (cellular compartment) were affected in aged seeds. To verify whether MetO, the oxidative posttranslational modification of proteins that can be reversed via the action of methionine sulfoxide reductase (Msr) enzymes, is involved in the aging of beech seeds, we identified and quantified 226 MetO-containing proteins, among which 9 and 19 exhibited significantly up- and downregulated MetO levels, respectively, in beech seeds under long-term storage conditions. Several Msr isoforms were identified and recognized as MsrA1-like, MsrA4, MsrB5 and MsrB5-like in beech seeds. Only MsrA1-like displayed decreased abundance in aged seeds. CONCLUSIONS: We demonstrated that the loss of membrane integrity reflected in the elevated abundance of membrane proteins had a higher impact on seed aging progress than the MetO/Msr system. Proteome analyses enabled us to propose protein Sec61 and glyceraldehyde-3-phosphate dehydrogenase as potential longevity modulators in beech seeds.


Assuntos
Fagus , Metionina , Proteínas de Plantas , Proteômica , Sementes , Fagus/metabolismo , Metionina/metabolismo , Metionina/análogos & derivados , Sementes/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Germinação , Espécies Reativas de Oxigênio/metabolismo , Regulação da Expressão Gênica de Plantas
11.
Sci Total Environ ; 934: 173122, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-38734086

RESUMO

Similar to soils, tree stems emit and consume nitrous oxide (N2O) from the atmosphere. Although tree leaves dominate tree surface area, they have been completely excluded from field N2O flux measurements and therefore their role in forest N2O exchange remains unknown. We explored the contribution of leaf fluxes to forest N2O exchange. We determined the N2O exchange of mature European beech (Fagus sylvatica) stems and shoots (i.e., terminal branches) and of adjacent forest floor, in a typical temperate upland forest in Germany. The beech stems, and particularly the shoots, acted as net N2O sinks (-0.254 ± 0.827 µg N2O m-2 stem area h-1 and -4.54 ± 1.53 µg N2O m-2 leaf area h-1, respectively), while the forest floor was a net source (2.41 ± 1.08 µg N2O m-2 soil area h-1). The unstudied tree shoots were identified as a significant contributor to the net ecosystem N2O exchange. Moreover, we revealed for the first time that tree leaves act as substantial N2O sinks. Although this is the first study of its kind, it is of global importance for the proper design of future flux studies in forest ecosystems worldwide. Our results demonstrate that excluding tree leaves from forest N2O flux measurements can lead to misinterpretation of tree and forest N2O exchange, and thus global forest greenhouse gas flux inventories.


Assuntos
Poluentes Atmosféricos , Fagus , Óxido Nitroso , Óxido Nitroso/análise , Óxido Nitroso/metabolismo , Fagus/metabolismo , Alemanha , Poluentes Atmosféricos/análise , Florestas , Monitoramento Ambiental , Brotos de Planta/metabolismo , Folhas de Planta/metabolismo
12.
Physiol Plant ; 176(3): e14334, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38705836

RESUMO

European beech is negatively affected by climate change and a further growth decline is predicted for large parts of its distribution range. Despite the importance of this species, little is known about its genetic adaptation and especially the genetic basis of its physiological traits. Here, we used genotyping by sequencing to identify SNPs in 43 German European beech populations growing under different environmental conditions. In total, 28 of these populations were located along a precipitation and temperature gradient in northern Germany, and single tree-based hydraulic and morphological traits were available. We obtained a set of 13,493 high-quality SNPs that were used for environmental and SNP-trait association analysis. In total, 22 SNPs were identified that were significantly associated with environmental variables or specific leaf area (SLA). Several SNPs were located in genes related to stress response. The majority of the significant SNPs were located in non-coding (intergenic and intronic) regions. These may be in linkage disequilibrium with the causative coding or regulatory regions. Our study gives insights into the genetic basis of abiotic adaptation in European beech, and provides genetic resources that can be used in future studies on this species. Besides clear patterns of local adaptation to environmental conditions of the investigated populations, the analyzed morphological and hydraulic traits explained most of the explainable genetic variation. Thus, they could successfully be altered in tree breeding programs, which may help to increase the adaptation of European beech to changing environmental conditions in the future.


Assuntos
Fagus , Estudo de Associação Genômica Ampla , Folhas de Planta , Polimorfismo de Nucleotídeo Único , Fagus/genética , Fagus/fisiologia , Polimorfismo de Nucleotídeo Único/genética , Folhas de Planta/genética , Folhas de Planta/anatomia & histologia , Folhas de Planta/fisiologia , Desequilíbrio de Ligação/genética , Meio Ambiente , Fenótipo , Genótipo , Alemanha
13.
Environ Monit Assess ; 196(6): 571, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38777936

RESUMO

This study was conducted to determine the changes in carbon stocks of oriental beech (Fagus orientalis) according to stand development stage in the Marmara Region of Türkiye. For this purpose, sample plots were taken from a total of 32 areas encompassing four stand development stages (young, middle age, mature and overmature stand). The diameter at breast height and height of all trees in the sample plots were measured, and only three dominant trees's ages per plot were determined. Aboveground carbon stock was calculated using equations developed for beech forests, while the coefficients in the Agriculture, Forestry and Other Land Use guide were used to determine belowground carbon stocks. A soil pit was dug in each plot and soil samples were taken at different depths (0-10, 10-30, 30-60, 60-100 cm). In addition, litters were sampled from four different 25 × 25 cm sections in each plot, and then the physical and chemical properties of the soil and litters were analysed. The variations in carbon stocks in above- and below-ground tree mass, litter and soil, and in ecosystem carbon stocks according to development stage were examined by analysis of variance and Duncan test, and the relationships between the carbon stocks were investigated by correlation analysis. Aboveground (AG) and belowground (BG) tree, soil and ecosystem carbon stocks showed significant differences between the four stand development stages (P < 0.05), but not the litter carbon stocks (P > 0.05). AG and BG tree and ecosystem carbon stocks increased with progressive stand development stages, while the soil carbon stock was the highest at the young stage. These findings will contribute to the preparation of forest management plans and the national greenhouse gas inventory.


Assuntos
Carbono , Monitoramento Ambiental , Fagus , Florestas , Solo , Fagus/crescimento & desenvolvimento , Carbono/análise , Solo/química , Turquia , Árvores , Agricultura Florestal , Ecossistema
14.
Sci Total Environ ; 937: 173321, 2024 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-38782287

RESUMO

The future performance of the widely abundant European beech (Fagus sylvatica L.) across its ecological amplitude is uncertain. Although beech is considered drought-sensitive and thus negatively affected by drought events, scientific evidence indicating increasing drought vulnerability under climate change on a cross-regional scale remains elusive. While evaluating changes in climate sensitivity of secondary growth offers a promising avenue, studies from productive, closed-canopy forests suffer from knowledge gaps, especially regarding the natural variability of climate sensitivity and how it relates to radial growth as an indicator of tree vitality. Since beech is sensitive to drought, we in this study use a drought index as a climate variable to account for the combined effects of temperature and water availability and explore how the drought sensitivity of secondary growth varies temporally in dependence on growth variability, growth trends, and climatic water availability across the species' ecological amplitude. Our results show that drought sensitivity is highly variable and non-stationary, though consistently higher at dry sites compared to moist sites. Increasing drought sensitivity can largely be explained by increasing climatic aridity, especially as it is exacerbated by climate change and trees' rank progression within forest communities, as (co-)dominant trees are more sensitive to extra-canopy climatic conditions than trees embedded in understories. However, during the driest periods of the 20th century, growth showed clear signs of being decoupled from climate. This may indicate fundamental changes in system behavior and be early-warning signals of decreasing drought tolerance. The multiple significant interaction terms in our model elucidate the complexity of European beech's drought sensitivity, which needs to be taken into consideration when assessing this species' response to climate change.


Assuntos
Mudança Climática , Secas , Fagus , Fagus/crescimento & desenvolvimento , Fagus/fisiologia , Florestas , Árvores/crescimento & desenvolvimento , Árvores/fisiologia
15.
Oecologia ; 205(1): 121-133, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38698245

RESUMO

Fine roots are multifunctional organs that may change function with ageing or root branching events from primarily absorptive to resource transport and storage functions. It is not well understood, how fine root branching patterns and related root functional differentiation along the longitudinal root axis change with soil chemical and physical conditions. We examined the variation in fine root branching patterns (the relative frequency of 1st to 4th root orders) and root morphological and chemical traits of European beech trees with soil depth (topsoil vs. subsoil) and soil chemistry (five sites with acid to neutral/alkaline bedrock). Bedrock type and related soil chemistry had an only minor influence on branching patterns: base-poor, infertile sites showed no higher fine root branching than base-rich sites. The contribution of 1st-order root segments to total fine root length decreased at all sites from about 60% in the topsoil (including organic layer) to 45% in the lower subsoil. This change was associated with a decrease in specific root area and root N content and an increase in mean root diameter with soil depth, while root tissue density did not change consistently. We conclude that soil depth (which acts through soil physical and chemical drivers) influences the fine root branching patterns of beech much more than soil chemical variation across soil types. To examine whether changes in root function are indeed triggered by branching events or result from root ageing and diameter growth, spatially explicit root physiological and anatomical studies across root orders are needed.


Assuntos
Fagus , Raízes de Plantas , Solo , Raízes de Plantas/anatomia & histologia , Fagus/anatomia & histologia , Fenótipo
16.
J Environ Radioact ; 277: 107450, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38762981

RESUMO

In the long-term after atmospheric deposit onto a forest ecosystem, Cs-137 becomes incorporated into the biogeochemical cycle of stable elements and progressively reaches a quasi-equilibrium state. This study aimed at determining to what extent Cs-137 activity distribution in tree vegetation could be predicted from that of stable caesium (Cs-133) and potassium (K), which are known to be stable chemical analogues and competitors for Cs-137 intake in tree organs. Field campaigns that focused on beech trees (Fagus sylvatica L.) were conducted in 2021 in three French forest stands with contrasted characteristics regarding either the contribution of global vs. Chornobyl fallouts, soil or climatic conditions. Decades after Cs-137 fallouts, it was found that more than 80% of the total radioactive inventory in the system remained confined in the top 20 cm mineral layers, while organic layers and beech vegetation (including roots) contributed each to less than 1.5%. The enhanced downward migration of Cs-137 in cambisol than podzol forest sites was presumably due to migration of clay particles and bioturbation. The distribution of Cs-137 and Cs-133 inventories in beech trees was very similar among sites but differed from that of K due a higher accumulation of Cs isotopes in roots (40-50% vs. < 25% for K). The aggregated transfer factor (Tag) of Cs-137 calculated for aerial beech organs were all lower than those reported in literature more than 20 years ago, this suggesting a decrease of bioavailability in soil due to ageing processes. Regarding their variability, Tags were generally lower by a factor 5 at the cambisol site, which was fairly well explained by a much higher value of RIP (radiocesium immobilisation potential). Cs-137 concentrations in trees organs normalized by the soil exchangeable fractions were linearly correlated to those of Cs-133 and the best fit was found for the linear regression model without intercept indicating that no more contribution of the foliar uptake could be observed on long term. Provided that the vertical distribution of caesium concentrations and fine root density are properly measured or estimated, Cs-133 was shown to be a much better proxy than K to estimate the root transfer of Cs-137.


Assuntos
Radioisótopos de Césio , Fagus , Florestas , Monitoramento de Radiação , Poluentes Radioativos do Solo , Fagus/metabolismo , Fagus/química , Poluentes Radioativos do Solo/análise , Poluentes Radioativos do Solo/metabolismo , Radioisótopos de Césio/análise , Radioisótopos de Césio/metabolismo , França , Árvores/química , Potássio/análise , Potássio/metabolismo , Acidente Nuclear de Chernobyl
17.
Appl Environ Microbiol ; 90(6): e0014224, 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38775476

RESUMO

Beech leaf disease (BLD) is a newly emerging disease in North America that affects American beech (Fagus grandifolia). It is increasingly recognized that BLD is caused by a subspecies of the anguinid nematode Litylenchus crenatae subsp. mccannii (hereafter L. crenatae), which is likely native to East Asia. How nematode infestation of leaves affects the leaf microbiome and whether changes in the microbiome could contribute to BLD symptoms remain uncertain. In this study, we examined bacterial and fungal communities associated with the leaves of F. grandifolia across nine sites in Ohio and Pennsylvania that were either symptomatic or asymptomatic for BLD and used qPCR to measure relative nematode infestation levels. We found significantly higher levels of infestation at sites visibly symptomatic for BLD. Low levels of nematode infestation were also observed at asymptomatic sites, which suggests that nematodes can be present without visible symptoms evident. Bacterial and fungal communities were significantly affected by sampling site and symptomology, but only fungal communities were affected by nematode presence alone. We found many significant indicators of both bacteria and fungi related to symptoms of BLD, with taxa generally occurring in both asymptomatic and symptomatic leaves, suggesting that microbes are not responsible for BLD but could act as opportunistic pathogens. Of particular interest was the fungal genus Erysiphe, which is common in the Fagaceae and is reported to overwinter in buds-a strategy consistent with L. crenatae. The specific role microbes play in opportunistic infection of leaves affected by L. crenatae will require additional study. IMPORTANCE: Beech leaf disease (BLD) is an emerging threat to American beech (Fagus grandifolia) and has spread quickly throughout the northeastern United States and into southern Canada. This disease leads to disfigurement of leaves and is marked by characteristic dark, interveinal banding, followed by leaf curling and drop in more advanced stages. BLD tends to especially affect understory leaves, which can lead to substantial thinning of the forest understory where F. grandifolia is a dominant tree species. Understanding the cause of BLD is necessary to employ management strategies that protect F. grandifolia and the forests where it is a foundation tree species. Current research has confirmed that the foliar nematode Litylenchus crenatae subsp. mccannii is required for BLD, but whether other organisms are involved is currently unknown. Here, we present a study that investigated leaf-associated fungi and bacteria of F. grandifolia to understand more about how microorganisms may contribute to BLD.


Assuntos
Bactérias , Fagus , Fungos , Doenças das Plantas , Folhas de Planta , Fagus/microbiologia , Fagus/parasitologia , Animais , Folhas de Planta/microbiologia , Folhas de Planta/parasitologia , Doenças das Plantas/microbiologia , Doenças das Plantas/parasitologia , Fungos/classificação , Fungos/isolamento & purificação , Fungos/genética , Fungos/fisiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Micobioma , Pennsylvania , Ohio , Microbiota , Nematoides/microbiologia
18.
Tree Physiol ; 44(6)2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38769932

RESUMO

Forest trees adopt effective strategies to optimize nitrogen (N) use through internal N recycling. In the context of more recurrent environmental stresses due to climate change, the question remains of whether increased frequency of drought or defoliation threatens this internal N recycling strategy. We submitted 8-year-old beech trees to 2 years of either severe drought (Dro) or manual defoliation (Def) to create a state of N starvation. At the end of the second year before leaf senescence, we labeled the foliage of the Dro and Def trees, as well as that of control (Co) trees, with 15N-urea. Leaf N resorption, winter tree N storage (total N, 15N, amino acids, soluble proteins) and N remobilization in spring were evaluated for the three treatments. Defoliation and drought did not significantly impact foliar N resorption or N concentrations in organs in winter. Total N amounts in Def tree remained close to those in Co tree, but winter N was stored more in the branches than in the trunk and roots. Total N amount in Dro trees was drastically reduced (-55%), especially at the trunk level, but soluble protein concentrations increased in the trunk and fine roots compared with Co trees. During spring, 15N was mobilized from the trunk, branches and twigs of both Co and Def trees to support leaf growth. It was only provided through twig 15N remobilization in the Dro trees, thus resulting in extremely reduced Dro leaf N amounts. Our results suggest that stress-induced changes occur in N metabolism but with varying severity depending on the constraints: within-tree 15N transport and storage strategy changed in response to defoliation, whereas a soil water deficit induced a drastic reduction of the N amounts in all the tree organs. Consequently, N dysfunction could be involved in drought-induced beech tree mortality under the future climate.


Assuntos
Secas , Fagus , Folhas de Planta , Estações do Ano , Árvores , Fagus/fisiologia , Fagus/metabolismo , Fagus/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Folhas de Planta/metabolismo , Árvores/fisiologia , Árvores/metabolismo , Nitrogênio/metabolismo , Ciclo do Nitrogênio
19.
Molecules ; 29(8)2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38675569

RESUMO

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.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas , Phytophthora , Doenças das Plantas , Compostos Orgânicos Voláteis , Compostos Orgânicos Voláteis/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Doenças das Plantas/microbiologia , Microextração em Fase Sólida , Quercus/química , Quercus/microbiologia , Fagus/microbiologia
20.
Proc Biol Sci ; 291(2020): 20232338, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38593851

RESUMO

Transcriptomics provides a versatile tool for ecological monitoring. Here, through genome-guided profiling of transcripts mapping to 33 042 gene models, expression differences can be discerned among multi-year and seasonal leaf samples collected from American beech trees at two latitudinally separated sites. Despite a bottleneck due to post-Columbian deforestation, the single nucleotide polymorphism-based population genetic background analysis has yielded sufficient variation to account for differences between populations and among individuals. Our expression analyses during spring-summer and summer-autumn transitions for two consecutive years involved 4197 differentially expressed protein coding genes. Using Populus orthologues we reconstructed a protein-protein interactome representing leaf physiological states of trees during the seasonal transitions. Gene set enrichment analysis revealed gene ontology terms that highlight molecular functions and biological processes possibly influenced by abiotic forcings such as recovery from drought and response to excess precipitation. Further, based on 324 co-regulated transcripts, we focused on a subset of GO terms that could be putatively attributed to late spring phenological shifts. Our conservative results indicate that extended transcriptome-based monitoring of forests can capture diverse ranges of responses including air quality, chronic disease, as well as herbivore outbreaks that require activation and/or downregulation of genes collectively tuning reaction norms maintaining the survival of long living trees such as the American beech.


Assuntos
Fagus , Humanos , Estações do Ano , Fagus/genética , Folhas de Planta/fisiologia , Florestas , Árvores/fisiologia , Transcriptoma
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