Search Results (1,375)

Severely degraded and carbonised archaeological wood recovered from waterlogged deposits presents major challenges for anatomical identification because long-term burial may preserve organic material while also producing structural collapse, heterogeneous alteration, and strongly contrasting mechanical properties. This case study evaluates an adaptive decision-making workflow that combines gradual dehydration and extended paraffin processing, preservation of anatomical orientation, trial microtome sectioning, and block-face examination. Six fragments were recovered from Early Medieval pit features at Babinci in northeastern Slovenia; six specimens were processed for detailed anatomical analysis. One specimen yielded diagnostically usable transverse, radial, and tangential thin sections and was identified as Populus sp. The other specimens did not yield diagnostically usable transverse thin sections and were identified as Quercus sp. primarily from trimmed block faces. Paraffin embedding improved handling and block-face preparation. The contribution is therefore a transparent workflow for switching between complementary analytical routes according to specimen behaviour. Full article

Background/Objectives: Citrus sinensis, Olea europaea var. sylvestris, Populus nigra, Prunus dulcis, and Punica granatum are economically and medicinally important perennial plant species. Carotenoid cleavage oxygenase (CCO) genes encode key enzymes involved in carotenoid degradation and play essential roles in plant growth, development, and responses to environmental stresses. In this study, a comprehensive genome-wide comparative analysis of the CCO gene family was conducted in C. sinensis, O. europaea var. sylvestris, P. nigra, P. dulcis, and P. granatum to investigate their structural diversity, evolutionary relationships, and potential biological functions. Methods: Chromosomal distribution, phylogenetic relationships, gene structure, conserved protein motifs, homology modeling, subcellular localization, cis-regulatory elements, and miRNA interactions were analyzed. Results: A total of 12, 23, 22, 11, and 17 CCO genes were identified in C. sinensis, O. europaea var. sylvestris, P. nigra, P. dulcis, and P. granatum, respectively. Most CCO proteins were acidic, and genes were concentrated on specific chromosomes. Phylogenetic analysis grouped CCO genes into three main clades. Gene structure analysis revealed intronless and intron-containing genes of varying lengths. Some CCO proteins possessed all conserved motifs, while others lacked certain motifs or had multiple copies. β-sheets were the predominant secondary structural elements, and CCO proteins were predicted to be localized in chloroplasts, mitochondria, peroxisomes, the cytoplasm, and the nucleus. Stress-related cis-elements and miRNAs were identified. Conclusions: These findings provide valuable insights into the diversity and evolutionary characteristics of the CCO gene family and suggest that CCO genes may contribute to plant stress responses and metabolic processes. Overall, this study provides a comprehensive comparative analysis of the CCO gene family in these five perennial plant species and offers a valuable genomic resource for future functional characterization, comparative genomic studies, and molecular breeding applications. Full article

Fusarium proliferatum is a fungal pathogen with an exceptionally broad host range, infecting ornamental plants and forest trees such as Populus and Cedrus deodara, and causing heart rot, root rot, and other diseases that lead to severe yield losses. It can also produce mycotoxins, including fumonisins, which threaten human and animal health. Conventional detection relies on isolation, culture, and morphological identification, which are time-consuming and prone to misidentification. Here, we established a rapid, visual molecular detection method by combining recombinase polymerase amplification (RPA) with the CRISPR/Cas12a system, targeting the F. proliferatum-specific gene Fpro_15953. The assay exhibited high specificity: the F. proliferatum isolate from C. deodara tested positive, while 37 non-target isolates (10 other Fusarium species, 10 other fungi, 15 oomycetes, and 2 Bursaphelenchus nematodes) produced no detectable signal. Under isothermal conditions at 37 °C, after 10 min of RPA followed by 10 min of Cas12a cleavage, as little as 0.001 ng·μL⁻¹ of F. proliferatum genomic DNA could be detected. The method further succeeded in detecting F. proliferatum in artificially inoculated C. deodara needles and Populus × hopeiensis stem and root segments. This RPA-CRISPR/Cas12a platform provides an efficient, accurate tool for F. proliferatum detection and supports rapid field diagnosis. Full article

(1) Background: The diversity and compositional structure of a soil’s microbial community play important roles in the function of the whole soil environment, making them important indicators of soil quality. Poplars grow rapidly, have broad adaptability, strong resistance, and significant ecological benefits, making them the primary timber species in northern China. This study aims to explore the differences and similarities among soil microbial communities of different poplar varieties by investigating the effects of soil factors on various poplar species, as well as the composition and diversity of their soil microbiomes, which holds practical significance. (2) Methods: In this experiment, soil samples from four different poplar varieties (YA: Populus × euramericana ‘102’; YB: Populus × euramericana ‘Guariento’; YC: Populus cathayana × canadensis ‘Xinlin 1’; YD: Populus × liaoningensis) were selected for the determination of their microbial communities, soil chemical properties and enzyme activities. (3) Results: Significant differences (p < 0.05) were observed among the four poplar varieties in ammonium nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃⁻-N), total nitrogen (TN), total carbon (TC), total phosphorus (TP), available phosphorus (AP), invertase (INV), amylase (AMY), urease (URE), neutral phosphatase (NEP) and N-acetyl-β-D-glucosaminidase (NAG). Additionally, strong correlations were observed between soil factors and microorganisms, particularly with TP, AP, NEP and URE. (4) Conclusions: Soil chemical properties and enzyme activities significantly affect both poplar growth and microbial community structure, though the impacts vary. There are both similarities and differences in the composition and diversity of soil microbial communities across different poplar varieties. Full article

Salt stress significantly constrains plant growth and development, with the root system serving as the primary organ for sensing and responding to salinity. Poplar (Populus spp.), a widely cultivated tree species, plays important roles in urban greening, windbreaks and sand fixation, and various economic sectors. In this study, we conducted a comparative analysis of the salt tolerance of root systems of six different poplar cultivars. Key physiological indicators—including root activity, ion homeostasis, reactive oxygen species (ROS)-scavenging capacity, and nitric oxide (NO) content—were evaluated under saline conditions. Our findings indicate that the salt resistance of the six cultivars follows the order: P. simonii > P. cathayana > P. tremula × P. alba ‘717’ > P. deltoides × P. euramericana ‘Nanlin 895’ > P. deltoides × P. euramericana ‘Bofeng 3’ > P. alba × P. glandulosa ‘84K’. Furthermore, a transcriptomic analysis was performed on the most resilient species, P. simonii. These results reveal that P. simonii primarily orchestrates its salt stress response through the modulation of MAPK cascades and nitrogen metabolism pathways. This research provides theoretical support for elucidating the molecular mechanisms underlying the salt stress response in poplars and offers a foundation for the molecular breeding of salt tolerant poplar varieties. Full article

Continuous sap-flow monitoring is a key approach for understanding water-use strategies of shelterbelt species in semi-arid sandy lands. This study investigated two tree species (Populus alba var. pyramidalis Bge. and Pinus sylvestris var. mongholica Litv.) and two shrub species (Salix psammophila C. Wang & C. Y. Yang and Atraphaxis bracteata Losinsk.) in the Zhanggutai region, southern Horqin Sandy Land. Sap flow, environmental variables, and precipitation were continuously measured during the 2019–2020 growing seasons. Stomatal conductance (g_s) and its sensitivity to vapor pressure deficit (VPD) were evaluated. Precipitation dropped from 302.3 mm in 2019 to 106.3 mm in 2020. Daily sap flow peaked mid-season and declined by 21.9%–29.2% during 2020. VPD and solar radiation were primary drivers with narrow response lags. Trees exhibited higher g_s and stronger stomatal sensitivity than shrubs, showing steeper declines as VPD rose, which indicates key drought adaptation and protective mechanisms. Conversely, shrubs maintained a moderate and more stable g_s profile throughout the growing season. In 2020, soil water deficits may force stomatal closure, causing a pronounced drop in baseline g_s and a subsequent decline in sensitivity across all species. This widespread environmental decoupling indicates a critical shift from an atmospheric demand-limited regime during the wet year to a supply-limited regime during the drought year. Overall, trees demonstrated more pronounced stand-scale hydroclimatic sensitivity than shrubs. Given the persistent water consumption by shrubs, our results suggest tree species may offer advantages in later forest restoration stages. Nevertheless, further studies integrating biomass growth and ecosystem water balance are needed to optimize sustainable shelterbelt management. Full article

Tugai forests are intrazonal riparian ecosystems formed along river valleys in arid and semi-arid regions and characterized by high biodiversity and complex vegetation structure. The aim of this study was to assess the phytocenological structure, species composition, and ecological characteristics of tugai forests distributed within the Kura River basin and the Nakhchivan Autonomous Republic of Azerbaijan. The study was conducted using classical geobotanical and phytocenological methods based on the Braun—Blanquet approach. The results revealed clear ecological differentiation among tugai forest formations depending on hydrological regime, groundwater conditions, and soil salinity. High species diversity and a multi-layered vegetation structure were identified within the Populeta—Salicetum—Ulmosum, Ulmeta, Populeta, Saliceta—Alnueta—Populeta, and Tamariceta formation groups, which develop mainly on alluvial soils under conditions of elevated moisture. In the Nakhchivan region, tugai forests adapted to more arid environments are distributed mainly along the Araz River and are dominated by Tamarix ramosissima, Populus euphratica, Populus nigra, and Salix species. Anthropogenic impacts, including grazing, deforestation, and hydrological alterations, were identified as major factors contributing to ecosystem degradation and reduction in vegetation cover. The obtained results confirm the high ecological and conservation significance of tugai forests and emphasize the necessity of their protection, restoration, and sustainable management. Full article

Understanding genotype × environment interactions (G × E) is essential for selection of stable and productive clones in poplar breeding. However, the performance of hybrid poplar clones often varies unpredictably across sites, hindering efficient regional deployment. In this study, we evaluated the growth performance of 21 hybrid Populus section Aigeiros clones under five contrasting environmental conditions (YI, SHAN, SHEN, FEI, and JUAN). At the end of the growing season, we measured tree height (H), diameter at breast height (DBH), and individual tree volume (V). Both parametric and non-parametric stability statistics were used to assess individual V and fitted a mixed linear model in ASReml–R to generate best linear unbiased prediction (BLUP) values for subsequent genotype plus genotype-by-environment (GGE) biplot analysis. All measured traits exhibited substantial phenotypic variation, with coefficients of variation ranging from 17% to 43%. Genotype, environment, and G × E interaction effects were all highly significant (p < 0.01). The GGE biplot explained 89.88% of the total variation in individual V across test environments. Clones 1617 and 1618 exhibited high productivity, broad stability and strong adaptability across sites. Site discrimination and representativeness analyses revealed that SHAN, SHEN, FEI and JUAN were more informative, whereas YI showed weaker genotype differentiation. Clones 1617 and 1618 were particularly well adapted to FEI and JUAN, while clones 81, 1618, 13–22, 1607, I–107 and 1617 performed favourably in the other mega-environment. Our results indicate that integrating BLUP with GGE biplot analysis provides a robust framework for dissecting G × E and guiding clone selection in multi-environment poplar trials. The study provides valuable insights for refining poplar deployment strategies under diverse environmental conditions. Full article

Soil pollution is one of the main threats to soil ecosystem health, and the combination of microbial remediation with phytoremediation can promote contaminant degradation and contribute to the revitalization of ecosystem functions. Plant interactions with the surrounding physical and biological environments determine the formation of new ecosystems, which, similarly to natural ones, can provide several ecosystem services. Despite the increasing diffusion of phytoremediation and the large areas potentially suitable for the application of these technologies, the delivery of ecosystem services during phytoremediation interventions has rarely been investigated. In the framework of a bio-phytoremediation project, the present work explored the capacity of a new plant cover created at a site under bio-phytoremediation (area: 0.52 ha) to provide supporting, regulating, and cultural Ecosystem Services. The daily cumulative cooling effect due to plant transpiration during summer was 12.7 °C m⁻² day⁻¹, with species characterized by the highest Leaf Area Index and leaf transpiration rates (such as Chrysopogon zizanioides, evergreen shrub species, and Populus nigra) contributing the most to air cooling. Thanks to plant photosynthesis, 177 kg of C was sequestered each year, while the air pollution intercepted by the plant leaves amounted to 1.82 kg per year. After 30 months of phytoremediation, an increase in soil microbial activity indicated a progressive improvement in soil quality. Similarly, the cytometric analysis of hepatopancreatic cells from isopods indicated that the bioindicator organism actively and positively responded to the recovering environment, thus supporting the effectiveness of the ongoing remediation of soil quality. Finally, the implementation of the bio-phytoremediation intervention led to the creation of new habitats, increased ecological connectivity in the surrounding urban area, and generated an aesthetic value comparable to that of urban greenery. These analyses provided evidence that these techniques not only supported soil remediation and site securing but also contributed to improving citizen well-being in the proximity of the site and the environmental quality of the area. These significant positive externalities of phytoremediation should be considered when selecting technologies for environmental clean-up. Full article

Geometric uniformity in lignocellulosic furnish plays a central role in determining the mechanical reliability and density stratification of engineered wood products. This study presents a comprehensive morphological assessment of wood strands produced from indigenous poplar (Populus nigra L.) and hybrid poplar (Populus × euramericana (Dode) Guinier) strands under full industrial flaking conditions. A total of 600 strands were characterized for weight, length, width, and thickness and analyzed using a multivariate statistical framework integrating Principal Component Analysis (PCA) and bivariate correlation modeling. Despite being processed to the same nominal target length (120 mm), the two provenances exhibited markedly different dimensional behaviors. Hybrid poplar strands were substantially heavier (mean 0.536 g vs. 0.291 g) and slightly thicker on average, while indigenous strands were marginally wider; strand length did not differ significantly between provenances (p = 0.354). PCA applied to four variables (weight, length, width, and mean thickness) revealed that weight and width were the dominant contributors to PC1 (57.0% of total variance), enabling clear separation of the two provenances into distinct multivariate clusters. These findings indicate that hybrid furnish, due to its coarser and more variable geometry, may require enhanced mat densification during hot pressing to minimize internal voids and achieve a stable vertical density profile (VDP). The dataset and analytical approach presented here provide actionable insights for optimizing flaker calibration, strand classification, and resin dosing strategies in the production of Oriented Strand Board (OSB) and Laminated Strand Lumber (LSL), particularly when integrating fast-growing hybrid poplar resources into industrial manufacturing lines. Full article

The present study investigated, for the first time, the synergistic effects of combining bark extractive impregnation with ammonia fuming, revealing promising enhancements in both the aesthetic and functional attributes of wood. This combined approach uses the bioactive and protective properties of natural extractives while also making ammonia fuming effective for wood species with low extractive content. Bark extracts of pedunculate oak (Quercus robur L.) and European beech (Fagus sylvatica L.) were investigated on wood specimens of European beech (with and without red heartwood), hornbeam (Carpinus betulus L.), and gray poplar (Populus × canescens). Oak bark extract contained substantially higher total extractives and polyphenols than beech bark extract. Treatments caused only minor changes in density and equilibrium moisture content (generally within ±8%), while some shrinkage parameters changed more noticeably. The largest improvement occurred in beech false heartwood, where volumetric shrinkage decreased by up to 16%. Both treatments darkened the wood surface, with oak bark extract producing significantly larger color changes; ammonia fuming further intensified these effects, especially in poplar. Durability improved markedly: mass loss caused by Coniophora puteana (Schumach.) P. Karst. and Trametes versicolor (L.) Lloyd decreased from 27%–38% in untreated samples to 0.58%–7.73% after treatment, improving durability classification from Durability Class 4 to classes 1–2. Bark extract treatments slightly reduced hardness but generally maintained or slightly increased compression strength. Full article

Soil nitrogen (N) mineralization plays a pivotal role in regulating N availability in forest ecosystems, which could not only be closely related to soil nutrient supply capacity but also profoundly affect the forest carbon sequestration. Broad-leaved forests play a key role in terrestrial carbon storage; however, soil net N mineralization rates (Rmin) vary considerably among different forest types and their underlying driving mechanisms remain poorly understood. In this study, three typical broad-leaved forests in Northeast China, namely Populus davidiana Dode forest (PF), Fraxinus mandshurica Rupr forest (FF), and Betula platyphylla Suk. forest (BF), were selected. The soil Rmin, environmental parameters, physicochemical properties, and microbial community characteristics were determined among the three broad-leaved forests to explore forest type differences in soil Rmin and their associated factors. The results showed that soil inorganic N contents differed significantly among the three forest types, with significantly higher values in FF than in PF and BF (p < 0.05). Soil Rmin also differed significantly among forest types, which was highest in FF, followed by PF and BF (2.17, 1.31, and 0.95 mg kg⁻¹ day⁻¹, respectively) (p < 0.05). Soil Rmin was significantly positively correlated with soil water content (SWC), soil temperature (ST), and pH, but there was a negative correlation to soil bulk density (BD) (p < 0.05). In addition, microbial biomass carbon, nitrogen, and phosphorus were significantly higher in FF than in PF and BF (p < 0.05). Variation in soil Rmin among three broad-leaved forests was significantly associated with the abundances of Ascomycota, Basidiomycota, and Mucoromycota, but not with bacterial community, suggesting a closer association between fungi and soil Rmin. Structural equation modeling (SEM) indicated that forest type was associated with soil microbial community structure and biomass through associations with soil environmental and physicochemical properties, in relation to soil Rmin. In conclusion, this study highlights the links between vegetation type and soil Rmin in broad-leaved forests, which deepens the theoretical understanding of forest soil N-limitation in Northeast China. Full article

The WUSCHEL-related homeobox (WOX) gene family plays crucial roles in plant growth, development, and stress responses. In this study, a comprehensive genome-wide analysis of WOX genes was conducted in three Populus species, P. euphratica, P. pruinosa, and P. deltoides. A total of 16, 16, and 21 WOX genes were identified, respectively, and classified into three clades (ancient, intermediate, and WUS/modern) based on phylogenetic relationships. Structural analyses revealed highly conserved homeodomain motifs and similar exon–intron organizations, indicating strong evolutionary conservation. Furthermore, synteny analyses demonstrated that whole-genome duplication or segmental duplication events were the primary drivers of WOX gene family expansion, with most duplicated gene pairs undergoing purifying selection. Promoter analysis identified abundant cis-acting elements related to light responsiveness, hormone signaling, and stress responses. Notably, transcriptomic profiling during seed germination under drought and salt stress revealed distinct interspecific expression patterns and temporal dynamics between the two desert poplars. Specifically, members such as PeWox11 and PpWox2 were significantly induced, suggesting their potential involvement in abiotic stress adaptation. These findings provide comprehensive insights into the evolutionary conservation and divergence of WOX genes in Populus, establishing a theoretical foundation for the molecular breeding of stress-tolerant woody plants. Full article

Soil salinization represents one of the most severe abiotic constraints on global forest productivity. Populus, the most widely cultivated fast-growing timber tree and a premier model woody plant, exhibits striking intrageneric variation in salt tolerance—from the extremely halophytic Populus euphratica to highly salt-sensitive cultivated clones. Understanding the molecular basis of this variation has profound implications for saline–alkali land reclamation and salt-tolerant variety breeding. This review systematically synthesizes current knowledge on Populus salt-stress responses, covering three primary injury mechanisms (osmotic stress, ionic toxicity, and oxidative damage) and the corresponding physiological countermeasures. We further survey functional genes across four major categories: ion transporters, osmotic-adjustment enzymes, antioxidant-defense components, and transcription factors. Crucially, we extend beyond the herbaceous-plant paradigm by examining salt-tolerance strategies that are specific to the woody architecture of Populus: long-distance radial and axial Na⁺ transport through tall stems, salt sequestration in senescent bark and wood parenchyma, and deep-root ion exclusion strategies. Comparative insights from other woody genera are incorporated to highlight convergent and divergent mechanisms. On this basis, we propose an integrated multi-level regulatory model in which Na⁺ compartmentalization/efflux serves as the core, ROS homeostasis as the key regulatory axis, and osmotic adjustment as the auxiliary strategy. Outstanding challenges—including unresolved primary salt-signal perception, insufficient pathway integration, and limited in planta gene-function verification—are critically assessed, and future research priorities encompassing multi-omics integration, CRISPR-based gene editing, and natural-population genomics are outlined. Full article

Background/Objectives: Cytokinin and auxin are essential for vascular development in plants. This study aims to explore whether these two hormones exhibit crosstalk in the cambium, analogous to that observed in the apical meristem. Methods: Using the hybrid poplar (Populus alba × P. glandulosa clone ‘84K’), we integrated gravitropic induction with transcriptomic analysis and identified the cytokinin biosynthesis gene PagIPT5 as differentially expressed in a tension wood induction system. PagIPT5 overexpression lines were generated and assessed for growth-related phenotypes. The interaction between cytokinin and auxin was investigated via anatomical observation, cell proliferation assays, in situ PCR, and immunofluorescence detection of auxin and cytokinin. Results: Compared with the wild type, PagIPT5 overexpression lines showed growth inhibition and an auxin-deficient phenotype. High PagIPT5 expression in the vascular cambium elevated cytokinin levels while reducing auxin levels, leading to decreased cambial cell proliferation and suppressed xylem development. However, in the tension wood induction system, both auxin and cytokinin levels increased in the vascular cambium of tension wood relative to opposite wood. Treatment with a superoxide anion activator promotes the accumulation of both auxin and cytokinin in 84K plants. Conclusions: These results revealed an antagonistic interaction between the two hormones in the cambium zone. However, this antagonism is attenuated in tension wood, which may be induced by the accumulation of superoxide anion in tension wood. Full article