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Plant–microbe interactions significantly influence plant growth dynamics and adaptability. This study explores the impact of metabolites on microbial biodiversity in shoot tips and wood of Populus nigra under greenhouse conditions, using high‐throughput sequencing and metabolite profiling. Branches from P. nigra were harvested, rooted, and transplanted into pots for growth. After 3 months, tissue samples from shoot tips and wood were collected, and metabolites extracted and analysed using GC‐MS and LC‐MS. Genomic DNA was extracted and subjected to high‐throughput sequencing for bacterial biodiversity profiling. Both datasets were analysed using bioinformatic and statistical pipelines. Metabolite profiling indicated that shoot tips had a higher relative abundance of primary and secondary metabolites, including sugars, fatty acids, organic acids, phenolic acid derivatives and salicinoids, while wood was enriched in flavonoids. Bacterial biodiversity also differed significantly between these tissues, with Clostridiales, Bacteroidales and Bacillales dominating in shoot tips, associated with rapid growth and anaerobic fermentation, while wood tissues were characterized by diazotrophs from Rhizobiales, Sphingomonadales and Frankiales. PCoA clustering confirmed tissue‐specific microbial differences. Functional analysis revealed an enrichment of fundamental cellular processes in shoot tips, while wood exhibited pathways related to degradation and mortality. Metabolite profiling revealed significant variations in primary and secondary metabolites, highlighting their influence on microbial biodiversity across plant tissues. The dominance of specific bacterial orders and distinct functional pathways in each tissue suggests a tailored microbial response to the unique environments of shoot tips and wood. [ABSTRACT FROM AUTHOR]

In the present study we investigated the combined effect of flow intermittence and wastewater treatment plant (WWTP) effluent on leaf litter decomposition in two Mediterranean streams with permanent and intermittent flow regimes. The litter decomposition experiment was performed using black poplar litter bags where we measured litter mass loss, fungal biomass, aquatic hyphomycete sporulation and species richness and C:N ratio. Afterwards, the remaining litter material from the different treatments was offered to the shredder Potamophylax latipennis in a microcosm laboratory experiment, and its growth and consumption rates were studied. We hypothesised that drying would decrease leaf litter decomposition in the permanent stream more than in the intermittent stream and that WWTP effluent would compensate for drying effects when both stressors interacted. The results indicated that drying has the greatest impact on the permanent stream, decreasing decomposition, aquatic hyphomycete species richness, and leaf litter quality. In the intermittent stream, WWTP effluent decreases aquatic hyphomycete species richness, but drying increases it, showing an opposing effect and a synergistic interaction. In the permanent stream drying provoked an increase in the shredder consumption rate. Thus, the expected more frequent intermittence in rivers under climate change may threaten the processing of organic matter. [ABSTRACT FROM AUTHOR]

From the early 2000s, many forestation projects were carried out in the flooding areas of the Po River to preserve abandoned or damaged riverbanks and establish natural populations of Populus nigra L. for species conservation and future seed collection activities. Different clones of P. nigra, belonging to a collection of the Centre for Forestry and Wood (CREA-FL), were planted. The group named 'POBIA' comprises 35 selected clones chosen for their survival ability and fast growth. After plantation and a few essential cultural inputs, four establishments were left undisturbed. This study highlights the survival, growth, and performance results of the 'POBIA' group compared to other not-selected clones. The 'POBIA' clones showed a higher survival than the not-selected clones. Moreover, the 'POBIA' groups showed a significantly higher C sink performance in three of four establishments, reaching 278.6 t ha−1 of CO2 obtained in thirteen years in one site. The management of 'POBIA' clones in reforestation projects agrees with the EU recommendations for a vital ecosystem service. [ABSTRACT FROM AUTHOR]

In this study a low cost and easily available Black Poplar Sawdust (Populus nigra L.) was converted into an efficient adsorbent for the removal of acetamiprid (AMR) and imidacloprid (ICR) pesticides from aqueous solutions. The effect of adsorption effecting parameters including initial pesticides concentration, variations in the adsorbent amount, time of contact, and pH were investigated to understand the adsorption process of both pesticides. Further the kinetic, thermodynamic, and isotherm models were used to get an insight into the process of adsorption taking place. The results of the study suggested that the isotherm data align effectively with both the Langmuir and Temkin isotherm models (both pesticides). The maximum adsorption capacity (qm) for AMR was found to be 25.22 mg g−1, while for ICR, it was 25.65 mg g−1. Furthermore, the adsorption kinetics were best described by the pseudo-second-order model with value of R2 = 0.9934 & 0.9964 respectively for AMR and ICR. The thermodynamic analysis confirmed the spontaneity and feasibility of the adsorption process, evident from the negative ∆G° values at different temperatures. The thermodynamics parameter values also suggested that the adsorption process is physisorption and exothermic due to the negative ∆H° value. From the results it was concluded that the devised adsorbent could be effectively used in reclamation pesticides contaminated water subjected to further verifications through testing against other pesticides. [ABSTRACT FROM AUTHOR]

In this study modified cellulose based adsorbent was prepared from Populus nigra plant, and used for elimination of metaldehyde (herbicide) from model waste water. The adsorbent was characterized through analytical technique such as FTIR, SEM, EDX and XRD for structural adsorption related parameters. The results of SEM showed the suitability of the material to be used as adsorbent and FTIR showed successful crosslinking of polyvinyl alcohol into cellulose structure. In order to get maximum reclamation benefits from adsorbent it was subjected to a number of tests evaluating the effect of metaldehyde concentration, sorbent dose, contact time, initial pH of solution and temperature. The maximum removal of 70 % was achieved under conditions of 80 mg/L metaldehyde concentration, 60 min contact time, pH of 8, 0.08 g sorbent dosage, and room temperature (25 °C). The Langmuir isotherm model with correlation coefficients of 0.9855 and maximum adsorption capacity recorded was 8.32 mg/g, while excellent agreement was shown by kinetic data with pseudo second order kinetic model with R 2 = 0.9876. Thermodynamic study indicated enthalpy change (ΔH° = −129 kJ/mol) to be negative, entropy change (ΔS° = 161.7 j/mol) positive, and the Gibbs free energy (ΔG) as negative showing that the process to be exothermic and feasible/spontaneous with an increase of randomness at solid liquid interface. The finding indicated that modified cellulose could be used as an efficient adsorbent for removal of metaldehyde from model waste water. However, further validation with other pollutants will be helpful in checking reproducibility of the present findings. [ABSTRACT FROM AUTHOR]

Research in fluvial biogeomorphology largely aims to promote our understanding of the interactions between riparian vegetation and fluvial morphodynamics within riverine ecosystems. Starting at the end of the last century, Angela M. Gurnell has made a major contribution to fluvial geomorphology by considering water flow and sediment transport in combinaton with riparian and later also aquatic vegetation and thus significantly promoting the fluvial biogeomorphological approach from its early days until today. The objective of the present paper is to present a set of studies and results obtained over the last 20 years mainly by the authors and many collaborators, including Angela M. Gurnell, on a panel of French rivers: the Tech, Garonne, Isère and Allier. In particular, feedback mechanisms between fluvial morphodynamics and riparian vegetation dynamics were investigated directly in the field and by using high‐resolution remote sensor systems at the scale of individual plants, populations, communities and landscapes as well as during semi‐controlled ex‐situ experiments at the scale of individual plants. Collectively, the authors' research conducted over the past 20 years has helped to elucidate some key aspects of the feedback dynamics between the lowest and highest levels of the riparian ecosystem organization. This article reviews and discusses those key aspects. The gradually obtained results have contributed to a better understanding and quantification of feedback between river morphodynamics and vegetation at nested spatiotemporal scales, from plant species traits to the riverine landscape. Furthermore, the biogeomorphological approach advocated for more than 20 years now has clearly facilitated the extension of the discipline of geomorphology to ecology in general and evolutionary ecology in particular and thus contributed to a more integrative vision of earth surface processes. [ABSTRACT FROM AUTHOR]

The ability of plants to colonize the fluvial environment and withstand uprooting by floods is largely controlled by the anchoring effect of roots. We characterized the root architecture and tensile strength of Alnus incana, a riparian tree species of the Betulaceae family for which there are no systematic observations of its vertical root structure. Four A. incana individuals and two nearby Populus nigra 3–10 years old growing on bars in gravel‐bed rivers were excavated. Their root structure was characterized in terms of root diameter, age, and depth and was related to sediment grain size and scour or deposition by floods. Root tensile strength was also measured as a function of root diameter using a load cell and displacement transducer attached to individual roots. The architecture of A. incana roots differed from that of nearby P. nigra, as all roots were in fine, sandy sediments, growing in one or more dense radial layers of which the most prominent was 0.2–0.3 m below the surface. The layers reflect deposition of fine sediments during floods. New fine sediment deposits promote the growth of a new root layer close to the aggraded ground surface. Root tensile strength was similar to Salicaceae species. These observations indicate that A. incana colonizes habitats that have already received fine sediment deposition, most likely induced by other young plants, especially Salicaceae species. A. incana then provides a high near‐surface root biomass, potentially further stabilizing surfaces and playing a complementary role as an ecosystem engineer. [ABSTRACT FROM AUTHOR]

Several researchers recognize the importance of plants as effective tools for environmental biomonitoring. The black poplar (Populus nigra L.) often emerges as a useful bioindicator of air quality in urban environments, where this tree species is widely employed for urban areas. Here, we used ICP-MS analysis to assess the presence and concentration of trace elements, with a special focus on heavy metals (HMs), in black poplar leaves and soil samples from three urbanized sites showing varying degrees of environmental quality. Specifically, the foliar concentrations of Zn (173.3 ppm), Cd (0.7 ppm), Co (1.1 ppm) and As (0.2 ppm) exceeded reference values for unpolluted sites, indicating potential environmental hazards. Additionally, we correlated the foliar concentrations of HMs with those quantified in soil and with air quality data provided by the regional air quality-monitoring network. Subsequently, we estimated the values of foliar fluctuating asymmetry, and evaluated their relationships with HM concentrations in both leaves and soil. Our results suggest that element concentrations in black poplar leaves are related to soil contamination and atmospheric quality, and the extent depends on the proximity to relevant pollution sources. Furthermore, the study species showed a pronounced accumulation capacity for some HMs (i.e., Zn, Cd) commonly found in particulate matter. The extent of foliar fluctuating asymmetry is related to atmospheric quality and HM soil concentration, possibly because of the growth anomalies induced by this kind of environmental contamination. Overall, our data indicate the study species can supply an effective biomonitoring service in urbanized contexts, offering valuable insights into the occurrence and biological implications of heavy metal contamination. [ABSTRACT FROM AUTHOR]

Background and aim: As a result of population growth, paper and wood products consumption has increased, and restrictions on using forest wood raw materials initiated the utilization poplar trees as fast-growing spices. The aim of this study was to focus on identification and comparison of the phenolic chemical components in poplar woods (populous nigra and populous deltoides). Materials and methods: In this study, three trees from each poplar tree were randomly felled in plantation near Nowshar, Iran. Then three discs were cut from each log. At first, wood was grounded and then wood flour extractive were measured using TAPPI standard procedure. Wood flour was extracted by acetone and extractives residue was added to BSTFA reactor and samples were kept in constant temperature bath at 70oC for an hour. The extractive samples were then analyzed by GC/MS. The compounds were identified using GC diagram which shows abundance and retention time of each compound, and calculation of quartz index and Adams table. Results: The result of GC-MS showed that there exist 68 and 105 compounds in wood of Populus nigra and Populus detoides, respectively. di-Limonene (30.26%), bis (2-ethylhexyl) phthalate (10.07%), Gamma-Sitosterol (1.06%), Hexadecanoic acid (2.0%), gamma-Terpinene (4.02%) and 4-Hydroxy-Benzoic acid (3.62%) were the most important compounds in wood of Populus detoides. There were the Limonene (25.62%), Anymol (5.29%), gamma-Terpinene (3.38%), 1, 2-Benzandicarboxylic acid (2.00%) and bis (2-ethylhexyl) phthalate (0.68%) as the most important compounds in wood of Populus nigra. Conclusion: The gas chromatographs showed that Limonene, Benzene methanol, alpha-Terpineol, beta-Bisabolene, Hexadecanoic acid and bis (2-ethylhexyl) phthalate were the 7 common compounds in the wood of Populus nigra and Populus deltoides. These compounds can play an important role in the durability and consumption of these woods. [ABSTRACT FROM AUTHOR]

Cellulose is the most common renewable polysaccharide on the planet and one of the most important sources of green support to generate catalysts. According to that, the fluffy cotton-like seed of the black poplar tree (Populus nigra subsp. betulifolia) was first used as a source of natural cellulose to construct the green, efficient, and recyclable catalyst for the synthesis of cyclic carbonate from carbon dioxide (CO2). Black poplar cotton (BPC) was efficiently oxidized to dialdehyde cellulose (DAC) using periodate and participated in the azido-Ugi four-component reaction (AU-4CRs) of sulfonamide, isocyanide, and sodium azide to produce tetrazole immobilized on cellulose (DAC-AU) as a ligand. Afterward, the heterogeneous biocatalyst (Cu(II)@DAC-AU) was prepared, and the catalytic activity of the biocatalyst was investigated in the cycloaddition reaction of epoxides and CO2. This study has proven to have the most optimal catalytic activity, including excellent performance up to 99% after 4 h under CO2 pressure of 1 bar. The hydroxy and tetrazole functional groups on the surface of cellulose can absorb CO2 effectively and improve its catalytic activity. This work highlights the applications of the biocatalyst in a cycloaddition reaction and provides an efficient remedy for the industrial conversion of CO2. [ABSTRACT FROM AUTHOR]

This article describes an effective approach for selecting suitable plant species for afforestation in post-mining rehabilitation. The research was conducted in the Western Black Sea region of Turkey. The aim of the research is to perform accurate criteria weighting and species prioritization for afforestation in post-mining degraded areas. This helps to ensure consistent conditions for the future use of the site as a forest, sustainability of nature, and selection of appropriate species adapted to the difficult post-mining conditions. In this study, which is a multi-criteria decision-making problem (MCDM), the weights of the criteria were determined by stepwise weight assessment ratio analysis (SWARA), and the priority ranking of the species was determined by the analytic hierarchy process (AHP). Analyses were carried out with 10 afforestation criteria and five tree species. According to the analysis, the top three ranked criteria are Economic Efficiency > Carbon Stock and Credit > Reducing Afforestation Cost. The five species' priority ranking is Robinia pseudoacacia L. (0.456) > Alnus glutinosa subsp. glutinosa (0.248) > Populus nigra subsp. nigra (0.146) > Salix alba L. (0.103) > Quercus robur subs. robur (0.048). The hybrid approach is expected to increase the effectiveness of post-mining rehabilitation works. [ABSTRACT FROM AUTHOR]

The article analyzes the viability and silvicultural and reclamation efficiency of stands of silver birch (Betula pendula Roth), black poplar (Populus nigra L.) and laurel poplar (Populus laurifolia Ledeb.) at the age of 33 years, growing in forest belts of checkerboard and row planting methods. Using modern research methods, temporary trial plots were established. It has been established that on chestnut, poorly developed and sandy loam soil with deep groundwater, stands of the noted tree species are at the stage of degression. The best viability (1.8 points) with planting safety of 57.5 % is typical for birch stands created by the checkerboard planting method. The worst viability (4.5 points) and low (14.7 %) preservation are distinguished by stands of black poplar, created by the same checkerboard planting method. The surveyed forest stands are characterized by a weakened and severely weakened vital state. The total lifespan of silver birch in the Koibal steppe can reach 45 years, and black and laurel poplars – no more than 35 years. The protective and silvicultural and reclamation properties of birch forest belts are not sufficiently expressed, they have a satisfactory (3a points) silvicultural and reclamation assessment, they require partial reconstruction and the resumption of agrotechnical care at the edges of the forest belts. Poplar forest belts have completely lost their protective and silvicultural-reclamation functions, correspond to a low (1 point) silvicultural-reclamation assessment, and need to be uprooted and replaced.

Abstract Background Despite the increasing number of epigenomic studies in plants, little is known about the forces that shape the methylome in long-lived woody perennials. The Lombardy poplar offers an ideal opportunity to investigate the impact of the individual environmental history of trees on the methylome. Results We present the results of three interconnected experiments on Lombardy poplar. In the first experiment, we investigated methylome variability during a growing season and across vegetatively reproduced generations. We found that ramets collected over Europe and raised in common conditions have stable methylomes in symmetrical CG-contexts. In contrast, seasonal dynamics occurred in methylation patterns in CHH context. In the second experiment, we investigated whether methylome patterns of plants grown in a non-parental environment correlate with the parental climate. We did not observe a biological relevant pattern that significantly correlates with the parental climate. Finally, we investigated whether the parental environment has persistent carry-over effects on the vegetative offspring’s phenotype. We combined new bud set observations of three consecutive growing seasons with former published bud set data. Using a linear mixed effects analysis, we found a statistically significant but weak short-term, parental carry-over effect on the timing of bud set. However, this effect was negligible compared to the direct effects of the offspring environment. Conclusions Genome-wide cytosine methylation patterns in symmetrical CG-context are stable in Lombardy poplar and appear to be mainly the result of random processes. In this widespread poplar clone, methylation patterns in CG-context can be used as biomarkers to infer a common ancestor and thus to investigate the recent environmental history of a specific Lombardy poplar. The Lombardy poplar shows high phenotypic plasticity in a novel environment which enabled this clonal tree to adapt and survive all over the temperate regions of the world.

Volatile organic compounds (VOCs) emitted by plants may help in understanding the status of a plant's physiology and its coping with mild to severe stress. Future climatic projections reveal that shifts in temperature and CO2 availability will occur, and plants may incur the uncoupling of carbon assimilation and synthesis of key molecules. This study explores the patterns of emissions of key VOCs (isoprene, methanol, acetaldehyde, and acetic acid) emitted by poplar leaves (more than 350) under a combined gradient of temperature (12–42 °C) and air CO2 concentration (400–1500 ppm), along with measurements of photosynthetic rates and stomatal conductance. Isoprene emission exhibited a rise with temperature and CO2 availability, peaking at 39 °C, the temperature at which methanol emission started to peak, illustrating the limit of stress tolerance to severe damage. Isoprene emission was uncoupled from the photosynthesis rate, indicating a shift from the carbon source for isoprene synthesis, while assimilation was decreased. Methanol and acetaldehyde emissions were correlated with stomatal conductance and peaked at 25 °C and 1200 ppm CO2. Acetic acid emissions lacked a clear correlation with stomatal conductance and the emission pattern of its precursor acetaldehyde. This study offers crucial insights into the limitations of photosynthetic carbon and stress tolerance. [ABSTRACT FROM AUTHOR]

In Northern Iraq, growing Populus nigra L. occurs in small areas and narrow plains among the mountains. The samples selected for temporal plotting assessed these strains' current and future growth. Thirty-five samples underwent random selection to cover an area of 0.1 ha. Measuring the DBH (diameter at mean height) and mean height of each sample comprised cutting two trees from the dominant and subdominant trees and taking the cross-sections at DBH. Statistical analysis established a nonlinear mathematical relationship between diameter growth and mean height diameter. Creating a tree table estimates the growth by listing diameter classes and frequencies for all samples. Populus volume per hectare's determination used the local Populus nigra volume database. Therefore, utilizing the stand table projection method helps determine the migration of tree diameter classes within the stand over the next two years. The prediction of the final stand volume and number of trees was also easy. Since these stands had intensive management, an assumption was the number of dead and felled trees was zero, with the number of mature trees implicitly measured by calculating the movement of the trees for the next two years. The difference between current and future volumes' evaluation revealed accurate growth. [ABSTRACT FROM AUTHOR]

Background: Despite the increasing number of epigenomic studies in plants, little is known about the forces that shape the methylome in long-lived woody perennials. The Lombardy poplar offers an ideal opportunity to investigate the impact of the individual environmental history of trees on the methylome. Results: We present the results of three interconnected experiments on Lombardy poplar. In the first experiment, we investigated methylome variability during a growing season and across vegetatively reproduced generations. We found that ramets collected over Europe and raised in common conditions have stable methylomes in symmetrical CG-contexts. In contrast, seasonal dynamics occurred in methylation patterns in CHH context. In the second experiment, we investigated whether methylome patterns of plants grown in a non-parental environment correlate with the parental climate. We did not observe a biological relevant pattern that significantly correlates with the parental climate. Finally, we investigated whether the parental environment has persistent carry-over effects on the vegetative offspring's phenotype. We combined new bud set observations of three consecutive growing seasons with former published bud set data. Using a linear mixed effects analysis, we found a statistically significant but weak short-term, parental carry-over effect on the timing of bud set. However, this effect was negligible compared to the direct effects of the offspring environment. Conclusions: Genome-wide cytosine methylation patterns in symmetrical CG-context are stable in Lombardy poplar and appear to be mainly the result of random processes. In this widespread poplar clone, methylation patterns in CG-context can be used as biomarkers to infer a common ancestor and thus to investigate the recent environmental history of a specific Lombardy poplar. The Lombardy poplar shows high phenotypic plasticity in a novel environment which enabled this clonal tree to adapt and survive all over the temperate regions of the world. [ABSTRACT FROM AUTHOR]

From the early 2000s, many forestation projects were carried out in the flooding areas of the Po River to preserve abandoned or damaged riverbanks and establish natural populations of Populus nigra L. for species conservation and future seed collection activities. Different clones of P. nigra, belonging to a collection of the Centre for Forestry and Wood (CREA-FL), were planted. The group named ‘POBIA’ comprises 35 selected clones chosen for their survival ability and fast growth. After plantation and a few essential cultural inputs, four establishments were left undisturbed. This study highlights the survival, growth, and performance results of the ‘POBIA’ group compared to other not-selected clones. The ‘POBIA’ clones showed a higher survival than the not-selected clones. Moreover, the ‘POBIA’ groups showed a significantly higher C sink performance in three of four establishments, reaching 278.6 t ha−1 of CO2 obtained in thirteen years in one site. The management of ‘POBIA’ clones in reforestation projects agrees with the EU recommendations for a vital ecosystem service.

Natural rubber, sourced from Hevea brasiliensis trees mainly in southeast Asia, is a critically important resource for transportation, national security, and medical products, among other uses. The guayule shrub is a domestic alternative source of natural rubber that is emerging with advantages over Hevea since it is well-suited for many medical and consumer applications. Biochar is a sustainable form of carbon made from biomass that is a potential replacement for petroleum-sourced carbon black, the most common filler for rubber composites. The coppiced-wood species hybrid poplar (Populus × canadensis) and Paulownia elongata are both rapidly growing hardwoods that have shown promise as feedstocks for biochar that can be used as fillers in common rubber composites such as Hevea natural rubber, styrene-butadiene, and polybutadiene. In this work, poplar and paulownia biochars were used to partially replace carbon black as filler in guayule rubber composites. Guayule composites with up to 60% of the carbon black replaced with poplar or paulownia biochar had higher tensile strength, elongation, and toughness compared to the 100% carbon black-filled control. These composites would be excellent candidates for rubber applications such as gloves, belts, hoses, and seals, while reducing dependence on fossil fuels and Hevea natural rubber. [ABSTRACT FROM AUTHOR]

Owing to the unique physicochemical properties and the low manufacturing costs, silver nanoparticles (AgNPs) have gained growing interest and their application has expanded considerably in industrial and agricultural sectors. The large-scale production of these nanoparticles inevitably entails their direct or indirect release into the environment, raising some concerns about their hazardous aspects. Callus culture represents an important tool in toxicological studies to evaluate the impact of nanomaterials on plants and their potential environmental risk. In this study, we investigated the chronic phytotoxic effects of different concentrations of novel bifunctionalized silver nanoparticles (AgNPs-Cit-L-Cys) and silver nitrate (AgNO3) on callus culture of Populus nigra L., a pioneer tree species in the riparian ecosystem. Our results showed that AgNPs-Cit-L-Cys were more toxic on poplar calli compared to AgNO3, especially at low concentration (2.5 mg/L), leading to a significant reduction in biomass production, accompanied by a decrease in protein content, a significant increase in both lipid peroxidation level, ascorbate peroxidase (APX), and catalase (CAT) enzymatic activities. In addition, these findings suggested that the harmful activity of AgNPs-Cit-L-Cys might be correlated with their physicochemical properties and not solely attributed to the released Ag+ ions and confirmed that AgNPs-Cit-L-Cys phytoxicity is associated to oxidative stress. [ABSTRACT FROM AUTHOR]

We present a genome assembly from an individual Populus nigra subsp. betulifola (black poplar; Tracheophyta; Malpighiales; Salicaceae). The genome sequence is 413.2 megabases in span. Most of the assembly (99.73%) is scaffolded into 19 chromosomal pseudomolecules. Mitochondrial and plastid genomes were also assembled. Three mitochondrial assemblies have lengths of 281.85, 335.57 and 186.15 kilobases, and the plastid genome has a length of 156.37 kilobases.

Black poplar is an economically important tree species that spreads in the Eastern and Central Anatolian regions of Türkiye and is used extensively in wood production. In addition to being used as a model organism for raw material production in breeding programs all over the world, its natural populations and plantations are used extensively, especially in Europe, due to its environmental plasticity and contribution to biodiversity. The habitat of the species is decreasing day by day and the continuity of the species is threatened in parallel with the increase in human activities such as planting fields and establishing hydroelectric power plants on the riverbanks where they naturally spread. In this study, genetic identity was given to individuals in black poplar populations distributed in the Aras River with 16 microsatellite markers. A high level of expected and observed heterozygosity was found in the populations. It turned out that the populations sampled from the sections of the Aras River between Iğdır-Kars and Erzurum-Kars originated from two genetic groups. It has been observed that there is a low rate of genetic differentiation between these two genetic groups due to high gene flow. The genetic data obtained can be used in the development of in-situ/ex-situ conservation programs and breeding programs for black poplar populations distributed in the Aras River.

The objective of this work was to improve the thermal stability, flame resistance, and surface properties of black poplar (Populus nigra L.) wood via different impregnation methods. The impregnation methods were employed through two distinct modalities: vacuum impregnation and immersion impregnation. Here, poplar wood was impregnated with calcium oxide solutions (1%, 3% and 5%). Fourier-transform infrared spectroscopic analysis revealed a shift in the typical peaks of cellulose, hemicellulose, and lignin depending on the impregnation method and solution ratio. Thermogravimetric analysis and the limiting oxygen index indicated that the samples impregnated with lime solutions exhibited higher thermal stability than the unimpregnated wood. Both impregnation methods caused a decrease in water absorption and thickness swelling of the sample groups. Using a scanning electron microscope, the effect of the impregnation process on the structure of the wood was examined. In terms of surface properties, it was determined that the surface roughness value increased. On the contrary, it was observed that the contact angle value also increased. A significant difference emerged between the applied methods. In conclusion, the applied lime minerals are suitable substances to increase the flame resistance and thermal stability of black poplar wood. [ABSTRACT FROM AUTHOR]

• This is the first report to include ultrasonic lactic acid extraction of active compounds from Populus nigra buds. • Contribution to the evaluation of antioxidant and anti-inflammatory activity in vitro and formulation based on particles with a photoprotective effect. • Novel phenolic compounds and organic acids identified for the first time in Populus nigra buds. • The extract of populus buds could be used as a photoprotective agent in the preparation of sun creams in the pharmaceutical industry and can be considered as a natural source of antioxidants. Many studies have been conducted on the biological potential of medicinal plant extracts; the present study looked into the use of antioxidant extracts from P.nigra buds in cosmetic formulations to boost photoprotection potential, with a particular emphasis on green extraction and the biological activities of these compounds. Extraction of phenolic compounds using ultrasonically assisted lactic acid reported content of 42.64 ± 0.16 mg GAE/g dw with an antioxidant potential of 72.20 ± 1.05 mmol TE/100g dw and 72.73 ± 2.59 mg AAE/g dw for DPPH • and OH • scavenging activities, respectively. Furthermore, a significant iron chelation capacity of the extract was recorded (104.45 ± 1.66 mg EDTA E/g dw). In addition, a strong anti-inflammatory activity of the extract was demonstrated (IC 50 : 0.122 and 0.1788%) for the inhibition of the mono-nitrogen oxide radical and cyclooxygenase respectively. The evaluation of the photoprotective effect expressed a high protection factor (34.81) and no irritant effects. Chemical analysis of the crude extracts was carried out by FTIR, LC-MS and GC-MS. The FTIR spectral study revealed the presence of different functional groups such as alcohols, ketones and amines, indicating the richness of the extract in various metabolites. GC-MS and LC-MS studies revealed the presence of 15 bioactive compounds, of which 9 phenolics and 6 organic acid components were identified for the first time in P.nigra buds. This approach using lactic acid as an ecological solvent and ultrasound as an alternative energy source represents a good choice for the design of an extraction system of bioactive compounds with antioxidant, anti-inflammatory and photoprotective properties. Further studies are needed to extend the screening approach anti-irritancy to develop antioxidant-enriched. [ABSTRACT FROM AUTHOR]

Plant hydraulic traits related to leaf drought tolerance, like the water potential at turgor loss point (TLP) and the water potential inducing 50% loss of hydraulic conductance (P 50), are extremely useful to predict the potential impacts of drought on plants. While novel techniques have allowed the inclusion of TLP in studies targeting a large group of species, fast and reliable protocols to measure leaf P 50 are still lacking. Recently, the optical method coupled with the gas injection (GI) technique has been proposed as a possibility to speed up the P 50 estimation. Here, we present a comparison of leaf optical vulnerability curves (OVcs) measured in three woody species, namely Acer campestre (Ac), Ostrya carpinifolia (Oc) and Populus nigra (Pn), based on bench dehydration (BD) or GI of detached branches. For Pn, we also compared optical data with direct micro-computed tomography (micro-CT) imaging in both intact saplings and cut shoots subjected to BD. Based on the BD procedure, Ac, Oc and Pn had P 50 values of −2.87, −2.47 and −2.11 MPa, respectively, while the GI procedure overestimated the leaf vulnerability (−2.68, −2.04 and −1.54 MPa for Ac, Oc and Pn, respectively). The overestimation was higher for Oc and Pn than for Ac, likely reflecting the species-specific vessel lengths. According to micro-CT observations performed on Pn, the leaf midrib showed none or very few embolized conduits at −1.2 MPa, consistent with the OVcs obtained with the BD procedure but at odds with that derived on the basis of GI. Overall, our data suggest that coupling the optical method with GI might not be a reliable technique to quantify leaf hydraulic vulnerability since it could be affected by the 'open-vessel' artifact. Accurate detection of xylem embolism in the leaf vein network should be based on BD, preferably of intact up-rooted plants. [ABSTRACT FROM AUTHOR]

Objective: Black poplar (Populus nigra L.) is a species native to Eurasia with a wide distribution area. It is an ecologically important species from riparian ecosystems, that is used as a parent of interspecific (P. deltoides x P. nigra) cultivated poplar hybrids. Variant detection from transcriptomics sequences of 241 P. nigra individuals, sampled in natural populations from 11 river catchments (in four European countries) is described here. These data provide new valuable resources for population structure analysis, population genomics and genome-wide association studies. Data description: We generated transcriptomics data from a mixture of young differentiating xylem and cambium tissues of 480 Populus nigra trees sampled in a common garden experiment located at Orléans (France), corresponding to 241 genotypes (2 clonal replicates per genotype, at maximum) by using RNAseq technology. We launched on the resulting sequences an in-silico pipeline that allowed us to obtain 878,957 biallelic polymorphisms without missing data. More than 99% of these positions are annotated and 98.8% are located on the 19 chromosomes of the P. trichocarpa reference genome. The raw RNAseq sequences are available at the NCBI Sequence Read Archive SPR188754 and the variant dataset at the Recherche Data Gouv repository under https://doi.org/10.15454/8DQXK5. [ABSTRACT FROM AUTHOR]

DNA cytosine methylation is an epigenetic mechanism involved in regulation of plant responses to biotic and abiotic stress and its ability to change can vary with the sequence context in which a cytosine appears (CpG, CHG, CHH, where H = Adenine, Thymine, Cytosine). Quantification of DNA methylation in model plant species is frequently addressed by Whole Genome Bisulfite Sequencing (WGBS), which requires a good-quality reference genome. Reduced Representation Bisulfite Sequencing (RRBS) is a cost-effective potential alternative for ecological research with limited genomic resources and large experimental designs. In this study, we provide for the first time a comprehensive comparison between the outputs of RRBS and WGBS to characterize DNA methylation changes in response to a given environmental factor. In particular, we used epiGBS (recently optimized RRBS) and WGBS to assess global and sequence-specific differential methylation after insect and artificial herbivory in clones of Populus nigra cv. 'italica'. We found that, after any of the two herbivory treatments, global methylation percentage increased in CHH, and the shift was detected as statistically significant only by epiGBS. As regards to loci-specific differential methylation induced by herbivory (cytosines in epiGBS and regions in WGBS), both techniques indicated the specificity of the response elicited by insect and artificial herbivory, together with higher frequency of hypo-methylation in CpG and hyper-methylation in CHH. Methylation changes were mainly found in gene bodies and intergenic regions when present at CpG and CHG and in transposable elements and intergenic regions at CHH context. Thus, epiGBS succeeded to characterize global, genome-wide methylation changes in response to herbivory in the Lombardy poplar. Our results support that epiGBS could be particularly useful in large experimental designs aimed to explore epigenetic changes of non-model plant species in response to multiple environmental factors. [ABSTRACT FROM AUTHOR]

Iran is located in a dry climate zone, and climate change has substantially reduced its precipitation and water resources. Reusing wastewaters from urban communities can meet some requirements for irrigation and fertilization of tree plantations in arid environments, leading to sustainable wastewater recycling, enhanced biomass production, and reduced land degradation. The objective of this study was to test the growth, biomass, nutrition, and heavy-metal accumulation of poplars [Populus nigra L. "62/154," P. alba L. "20/45," P. euramericana (Dode) Guinier "92/40"], and willow (Salix excelsa S.G. Gmel) in a pot experiment at four and eight months after planting when grown in soils irrigated with tap water (SITW) and wastewater (SIWW). After four months, SIWW treatment had no significant effect on growth, biomass, nor absorption of macronutrients. After eight months, SIWW treatment of poplars and willow significantly (p = 0.000) increased: (1) height, (2) leaf area, (3) root, stem, leaf, and total biomass, and (5) phytoextraction and phytoaccumulation of macro-/micro-nutrients and heavy metals in tree tissues, over trees receiving the SITW treatment. There were significant differences in growth, biomass, and accumulation of micronutrients and heavy metals in poplar versus willow tissues, with the highest biomass production and tissue-specific content of heavy metals in P. nigra trees, and the greatest total concentrations of heavy metals in P. alba and S. excelsa trees. In contrast, uptake of Fe, Cu, Ni, Cr and Pb were similar between poplar and willow, and phytoaccumulation of these elements was primarily in the roots. Leaf concentrations were highest for Zn and Mn. While P. nigra outperformed all other species overall, tolerance index (TI; defined as the tolerance to the heavy metals as calculated by the ratio of the biomass of SIWW trees relative to SITW trees) values exceeding 100% for all one-year-old poplar and willow trees demonstrated that they can be considered for planting in soil affected by urban wastewaters with similar contaminant profiles as in the current study. Since the species would differ in their growth, biomass, and phytoremediation responses to the nutrient and heavy metal concentrations of the wastewater over time, this research is important for the development of silvicultural prescriptions of these fast-growing trees that support effective wastewater reuse strategies throughout heterogeneous landscapes and across variable human community resources and needs. [ABSTRACT FROM AUTHOR]

Plant endophytic bacteria play important roles in plants' growth and resistance to stress. It is important to characterize endophytic bacteria to be able to understand their benefits. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) has become a powerful technique for bacterial identification due to its high throughput and simple procedures. In this study, the endophytic bacteria separated from Populus (the leaves, roots and stems of Populus tomentosa Carrière; stems of Populus nigra Linn. var. nigra; and stems of Populus canadensis Moench) were identified and classified based on MALDI-TOF MS data and 16S rRNA gene sequencing. The sampling and preparation of bacteria were optimized to obtain meaningful protein mass fingerprints. The composite correlation index (CCI) values of the inter-genera and inter-species protein mass fingerprints demonstrated sufficient differences between the strains. In the CCI value matrix for ten species in the same genus, all the CCI values were less than 0.5. Among the species, 95.6% of all the CCI values were less than 0.5. After data processing, the classification capacity of the protein mass fingerprints was verified using inter-specific and inter-generic PCoA. To compare different methods' potential for differentiation and phylogenetic analysis, a dendrogram of the MS profiles and a phylogenetic tree based on the 16S rRNA gene sequences were constructed using 61 endophytic bacteria found in Populus. The clustering and grouping results show that the phylogenetic analysis based on MALDI-TOF MS is similar to that based on 16S rRNA gene sequencing. This study provides a valuable reference for differentiating and identifying endophytic bacteria according to their protein mass fingerprints. [ABSTRACT FROM AUTHOR]

Growing lignocellulosic crops on marginal lands is a promising solution for sustainable biofuel production. We evaluated the productivity of bioenergy cropping systems (switchgrass [Panicum virgatum L., var. Cave‐In‐Rock], miscanthus [Miscanthus × giganteus, 'Illinois clone'], hybrid poplar [Populus nigra × P. maximowiczii A. Henry 'NM6'], native grasses [five species], early successional vegetation, and restored prairie vs. historical vegetation [as reference control]) with and without nitrogen fertilization on low‐fertility former cropland at five sites in the Great Lakes Region, United States. We reported biomass yields for the first 7 years after establishment. Switchgrass was most consistently productive across all sites but miscanthus was more productive at three of the five sites. When averaged across sites, years, and nitrogen (N) treatments, biomass yields followed the order miscanthus > switchgrass > hybrid poplar ≈ native grasses > restored prairie > early successional vegetation ≈ historical vegetation, but varied substantially by crop and site, with a significant crop by site interaction. Yields of miscanthus and switchgrass peaked after four–five growing seasons and declined thereafter, while yields of both native grasses and restored prairie increased throughout 6 years with no sign of follow‐on decline, suggesting that polycultures may outperform monocultures over the long term. Yields of early successional vegetation—similar in composition to historical vegetation at each site—did not improve with time. Nitrogen fertilization increased the yields of all cropping systems at all sites. Our results demonstrate the viability of low‐productivity former cropland for long‐term bioenergy production and suggest there is no single crop best suited for all low fertility soils. Core Ideas: Miscanthus and switchgrass performed well on marginal lands in the upper US Midwest.Switchgrass performed better over a wide range of soils and climates.Monocultures out‐yielded polycultures initially, but polycultures may outperform monocultures over the long term.Nitrogen fertilization increased the productivity of all cropping systems at all sites.No single crop appears best suited for all low fertility soils in the upper US Midwest. [ABSTRACT FROM AUTHOR]

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SUMMARY: Photorespiration is an essential metabolic mechanism associated with photosynthesis; however, little is known about the photorespiratory pathway of conifer gymnosperms. Metabolite analyses of the leaves of 27 tree species showed that the mean glycerate content in conifer leaves was lower than that in angiosperm leaves. We performed experiments where [13C]‐serine was fed to detached shoots of a conifer (Cryptomeria japonica), via the transpiration stream, and compared the labeling patterns of photorespiratory metabolites with those of an angiosperm tree (Populus nigra), because glycerate is produced from serine via hydroxypyruvate in peroxisomes. In P. nigra, hydroxypyruvate, glycerate and glycine were labeled with 13C, whereas in C. japonica, glycolate and a non‐canonical photorespiratory metabolite, formate, were also labeled, suggesting that an H2O2‐mediated non‐enzymatic decarboxylation (NED) reaction occurs in C. japonica. We analyzed changes in the metabolite contents of leaves kept in the dark and leaves exposed to illuminated photorespiration‐promoting conditions: a positive relationship between formate and serine levels in C. japonica implied that the active C1‐metabolism pathway synthesizes serine from formate. Leaf gas exchange analyses revealed that CO2 produced through NED was recaptured by chloroplasts. Database analysis of the peroxisomal targeting signal motifs of an H2O2‐scavenging enzyme, catalase, derived from various species, including nine coniferous species, as well as analyses of peroxisomal fractions isolated from C. japonica and P. nigra leaves indicated that conifer peroxisomes had less catalase activity. These results suggest that NED and the subsequent C1 metabolism are involved in the photorespiratory pathway of conifer leaves, where peroxisomes have intrinsically low catalase activity. Significance Statement: Photorespiration is a crucial metabolism that has a significant impact on the net CO2 fixation rates and energy‐use efficiencies of plants. It is thought that the photorespiratory pathway is identical among tree species; however, this study demonstrates that conifer gymnosperms have a different photorespiratory mechanism than that of angiosperm trees. [ABSTRACT FROM AUTHOR]

Knowledge of the quantity of woody biomass of poplar short-rotation coppice (SRC) on agricultural land is a basic tool for management decisions like rotation length, volume production and the financial balance sheet of economic activities. The expansion of SRC requires a fast, reliable, easily applicable and cheap method for estimating the biomass yield, but existing methods are based on labour-demanding and lengthy measurements of all shoots per tree. The objective of this study was to verify a novel rapid biomass estimation method that uses averaged attributes of only a few largest shoots as a predictor variable for woody biomass in a poplar SRC, hybrid clone J-105 (Populus nigra × P. maximowiczii). Using data from 39 sample stumps with 187 shoots in total, we modelled shoot biomass as a function of an increasing number of shoots in interaction with different shoot parameters at two poplar SRC plantations. Results showed that the DBH of only three of the largest shoots per stump proved to be accurate estimators of the total shoot biomass of the individual stump. Comparison of biomass estimates at the stand level with a real amount of biomass indicated differences between 6-14%, depending on the site. [ABSTRACT FROM AUTHOR]

In this study, the poplar doubled haploid (DH) plants were used as the experimental material to explore the huge phenotypic differences between homozygous DH plants and the paternal plants, and the molecular regulation mechanism of the differential phenotypes. In this experiment, through morphological and histological observation and statistics, we found that the double haploid plants had significantly reduced plant height and ground diameter, increased leaf aspect ratio, premature senescence phenotype of top bud, and significant changes in the shape and cell area of the shoot apical meristem. Significantly differentially expressed genes were obtained using RNA-seq transcriptome sequencing. They were subjected to GO enrichment and KEGG analysis. Transcription factors with key functions were screened out for qRT-PCR to verify gene expression changes to predict gene function. The results showed that after the IAA and ABA treatment, the expression levels of some hormone-responsive genes in wild type plants were significantly changed with different treatment time. In the dihaploid plants, the corresponding genes also changed to different degrees, which reflected the changes in the response of the dihaploid plants to hormones. Compared to in WT, the differential expressed genes in the double haploids were involved in multiple physiological process such as response to oxidative stress, response to salicylic acid, plant pathogen interaction, and plant hormone signal transduction. A TF–centered gene regulatory network for phytohormone synthesis and plant senescence was constructed with the expression patterns of differentially expressed transcription factors (TFs). This study increases researchers' understanding of the regulation of poplar growth and development and provides new research ideas for the creation of new species of poplar. [ABSTRACT FROM AUTHOR]

An association genetics approach was used to examine individual genes and alleles at several loci responsible for complex traits controlling wood traits (cellulose, lignin, and 6C sugar) in European black poplar (Populus nigra). Due to fast growth, clonal propagation and availability of genomic resources have allowed us to investigate further genetic control of wood traits in the species. From thirty-nine candidate genes, 384 SNPs were successfully genotyped in a clonally replicated 288 P. nigra clone population. Only 50.5% of these markers were polymorphic that could be used in association mappings. The association population (4 ramets per clone) was phenotyped for cellulose, lignin, and 6C sugar contents. Moderately high heritabilities were observed for cellulose and 6C sugar while it was low in lignin. Furthermore, a moderately strong and positive genetic correlation was found between cellulose and lignin which may hinder genetic improvement in cellulose content due to the correlated response on lignin. The LD, across all candidate genes, showed a rapid decay with physical distance. Single-marker-based association tests using GLM and MLM models were implemented to identify associations for cellulose, lignin, and 6C sugar contents. Eleven unique single marker associations for cellulose, 5 for lignin, and 6C sugar contents were identified from 39 candidate genes, but only one marker for cellulose content (CesA3A-15-456) had a significant association with cellulose and with dominant gene effect after multiple test correction was applied. The percent of total variation explained by significant single marker associations ranged from 3 to 9.2% in cellulose, 2.8 to 3.8% in lignin, and 3.2–5.5% in 6C sugar contents, respectively. Given the rapid decay of within-gene linkage disequilibrium, limitation of sample size, overcorrection for false positives, and intensity of phenotypic selection, it is likely that some of these single marker associations are genuine and deserve to be further investigated with a larger and diverse study population. [ABSTRACT FROM AUTHOR]

Black poplar buds have high contents of many compounds with therapeutic potential, which are useful in cosmetics and the treatment of various dermatitis, respiratory diseases, etc. The aim of this study was to identify and exploit the local plant resources with biologically active properties from the Dobrogea area, Romania. For this purpose, materials were collected from the mentioned area, and macerates of black poplar were prepared in order to evaluate their qualities as antioxidant and antimicrobial agents. Three different black poplar buds' hydroalcoholic macerates were analyzed by the Folin–Ciocâlteau method to estimate the total content of phenolic compounds, by the HPLC-DAD method for identification and quantification of the main bioactive compounds and by the DPPH radical scavenging method to evaluate the antioxidant activity. All hydroalcoholic macerates showed high concentrations of phenolic compounds, the main individual compounds being gallic acid, chlorogenic acid, cinnamic acid, and methyl gallic acid. The antioxidant activity of the black poplar buds' hydroalcoholic macerates, evaluated by the DPPH radical scavenging test, showed high values, between 496 and 1200 mg GAE /100 g d.w. The Cd, Cu, Zn, Ni, and Pb concentrations released in dry poplar buds, determined by AAS, were below the detection limits. Hydroalcoholic macerates of black poplar were tested against two groups of gram-positive bacteria (Enterococcus and Staphylococcus) using an agar well diffusion assay. The in vitro inhibitory activities of the macerates were important and ranged from 8.2–9.4 mm inhibition zones (Staphylococcus) to 8.6 −10 mm inhibition zones (Enterococcus). [ABSTRACT FROM AUTHOR]

Leaf blight is a fungal disease that mainly affects the growth and development of leaves in plants. To investigate the molecular mechanisms of leaf blight defense in poplar, we performed RNA-Seq and enzyme activity assays on the Populus simonii × Populus nigra leaves inoculated with Alternaria alternate fungus. Through weighted gene co-expression network analysis (WGCNA), we obtained co-expression gene modules significantly associated with SOD and POD activities, containing 183 and 275 genes, respectively. We then constructed a co-expression network of poplar genes related to leaf blight resistance based on weight values. Additionally, we identified hub transcription factors (TFs) and structural genes in the network. The network was dominated by 15 TFs, and four out of them, including ATWRKY75, ANAC062, ATMYB23 and ATEBP, had high connectivity in the network, which might play important functions in leaf blight defense. In addition, GO enrichment analysis revealed a total of 44 structural genes involved in biotic stress, resistance, cell wall and immune-related biological processes in the network. Among them, there were 16 highly linked structural genes in the central part, which may be directly involved in poplar resistance to leaf blight. The study explores key genes associated with leaf blight defense in poplar, which further gains an understanding of the molecular mechanisms of biotic stress response in plants. [ABSTRACT FROM AUTHOR]

Populus nigra ita. is an important tree species for preventing rainfall-triggered shallow landslides and hydraulic bank erosion in New Zealand. However, the quantification of its spatial root distribution and reinforcement remains challenging. The objective of this study is to calibrate and validate models for the spatial upscaling of root distribution and root reinforcement. The data were collected in a 26-year-old "Tasman" poplar stand at Ballantrae Hill Country Research Station in New Zealand. We assessed root distribution at different distances from the stem of four poplar trees and from eleven soil pits along a transect located in a sparse to densely planting poplar stand. 124 laboratory tensile tests and 66 field pullout tests on roots with diameters up to 0.04 m were carried out to estimate root mechanical properties. The results show that the spatial distribution of roots can be well predicted in trenches of individual tree root systems (R2 = 0.78), whereas it tends to overestimate root distribution when planting density was higher than 200 stems per hectare. The root reinforcement is underestimated within single tree root systems (R2 = 0.64), but it performs better for the data along the transect. In conclusion, our study provided a unique and detailed database for quantifying root distribution and reinforcement of poplars on a hillslope. The implementation of these models for the simulation of shallow landslides and hydraulic bank erosion is crucial for identifying hazardous zones and for the prioritization of bio-engineering measures in New Zealand catchments. Results from this study are useful in formulating a general guideline for the planning of bio-engineering measures considering the temporal dynamics of poplar's growth and their effectiveness in sediment and erosion control. [ABSTRACT FROM AUTHOR]

In this study, black poplar (Populus nigra) wood from Zanjan province was used in two age groups of 18 and 38-years old. Timbers with thicknesses of 4, 5 and 6 cm were prepared from each age group. The prepared timbers were modified during the heat treatment process (Thermowood) at a constant temperature of 212 °C. Experimental samples were cut from the surface and middle depth of heat-treated timbers. Heat-treated and control wood samples were subjected to accelerated weathering for 150 hours. Color lightness (L*), color difference (AE*) and water droplet contact angle were measured for heat-treated and control samples before and after weathering. In order to investigate the wettability, the contact angle of the static water drop - was measured according to the ASTM D 5946 procedure. In general, before weathering, the brightness of the heat-treated samples decreased compared to the control sample, but after weathering, the lightness of the control samples decreased and the lightness of the heat-treated samples increased. Also, the value of color difference of samples after weathering compared to before weathering showed a significant decrease statistically. Heat treatment increased the contact angle of water droplets of the samples by 60.31% and the contact angle of water droplets of the heat-treated and control samples increased significantly after weathering compared to before weathering. [ABSTRACT FROM AUTHOR]

The NAC transcription factor family is well known to play vital roles in plant development and stress responses. For this research, a salt-inducible NAC gene, PsnNAC090 (Po-tri.016G076100.1), was successfully isolated from Populus simonii × Populus nigra. PsnNAC090 contains the same motifs at the N-terminal end of the highly conserved NAM structural domain. The promoter region of this gene is rich in phytohormone-related and stress response elements. Transient transformation of the gene in the epidermal cells of both tobacco and onion showed that the protein was targeted to the whole cell including the cell membrane, cytoplasm and nucleus. A yeast two-hybrid assay demonstrated that PsnNAC090 has transcriptional activation activity with the activation structural domain located at 167–256aa. A yeast one-hybrid experiment showed that PsnNAC090 protein can bind to ABA-responsive elements (ABREs). The spatial and temporal expression patterns of PsnNAC090 under salt and osmotic stresses indicated that the gene was tissue-specific, with the highest expression level in the roots of Populus simonii × Populus nigra. We successfully obtained a total of six transgenic tobacco lines overexpressing PsnNAC090. The physiological indicators including peroxidase (POD) activity, superoxide dismutase (SOD) activity, chlorophyll content, proline content, malondialdehyde (MDA) content and hydrogen peroxide (H2O2) content were measured in three transgenic tobacco lines under NaCl and polyethylene glycol (PEG) 6000 stresses. The findings reveal that PsnNAC090 improves salt and osmotic tolerance by enhancing reactive oxygen species (ROS) scavenging and reducing membrane lipid peroxide content in transgenic tobacco. All the results suggest that the PsnNAC090 gene is a potential candidate gene playing an important role in stress response. [ABSTRACT FROM AUTHOR]

Several bio-waste materials have been used for the efficient decontamination of water pollutants. Besides, Populus nigra leaf (PNL) waste is a readily available biodegradable material, which has not been exploited as an adsorbent for water treatment. This research evaluated the potentials of PNL bio-waste as a low-cost sorbent for the decontamination of vegetable oil (VO) from simulated oil-polluted water. The bio-sorbent was characterized by the FTIR, SEM, EDX, TGA and BET techniques. The PNL characterizations revealed a porous structure possessing several functionalities exploited in the uptake of VO. The BET characterizations of PNL revealed a surface area of 16.85 m2/g, a pore diameter of 5.16 nm and a pore volume of 0.00631 cm3/g. The temperature (300–320 K), time (1.0–12.0 min) and oil concentration (200 – 1000 g/L) impacted the VO uptake on PNL, while the influence of pH (2.0–9.0) was insignificant. The pseudo-second-order (R2 > 0.9997) and Langmuir (R2 > 0.9845) models were best fitted to the kinetics and isotherm modeling, respectively, with a monolayer uptake of 2.382 g/g. The film diffusion and intraparticle diffusion mechanisms were both involved in the overall uptake of VO on PNL. The thermodynamic evaluation showed an exothermic (ΔH° = − 19.13 kJ/mol), spontaneous (ΔG° = − 2.4 to − 1.53 kJ/mol) and physical sorption, while 93.6% of the VO was recovered from the oil-loaded PNL using petroleum ether as eluent. Besides, the regenerated PNL sorbent exhibited great potential for reuse in the sorption of VO sorption, which proves the viability of the novel bio-waste for the treatment of oil-contaminated water. [ABSTRACT FROM AUTHOR]

European black poplar (Populus nigra L.) is a pioneer species that belongs to the Salicaceae family and occurs in riparian ecosystems. It is one of the most endangered forest species in its entire distribution area. In Croatia, black poplars are considered an economically important forest species, but mostly clones originate from crossing combinations with American and European black poplar (Populus × canadensis Moench), while a small number of clones are native black poplar. Studies on native black poplar are quite rare and the generative propagation has not been used. The aim of this study was to gain knowledge on the production of high-quality black poplar seedlings and to carry out the selection of genotypes with the aim of establishing a base for future breeding. The female black poplar tree was selected on phenotypic characteristics in the area of Forest Administration Osijek, Forest Office Valpovo. The tree was cut down in April 2019, and branches with half-open seed capsules on catkins were collected. The branches were transferred to the Croatian Forest Research Institute’s greenhouse, where the catkins opened under the influence of the high temperature. Sowing was done in different substrates to test their effectiveness. Black poplar seedlings were selected and transplanted with regard to development and height growth. The results showed differences in height growth between plants sown in two different substrates and the occurrence of fungal diseases only on plants sown in pure sand. With subsequent multiple propagation using cuttings and selection by genotype, it is expected that it will be possible to identify several clones of native black poplar that will be introduced for use in forestry in Croatia. The use of quality plants grown from seeds will increase the genetic diversity and preserve the native black poplar gene pool.

In the current paper, we present the results of Kazakh propolis investigations. Due to limited data about propolis from this country, research was focused mainly on phytochemical analysis and evaluation of propolis antimicrobial activity. uHPLC-DAD (ultra-high-pressure-liquid chromatography coupled with diode array detection, UV/VIS) and uHPLC-MS/MS (ultra-high-pressure-liquid chromatography coupled with tandem mass spectrometry) were used to phytochemical characteristics while antimicrobial activity was evaluated in the serial dilution method (MIC, minimal inhibitory concentration, and MBC/MFC, minimal bactericidal/fungicidal concentration measurements). In the study, Kazakh propolis exhibited a strong presence of markers characteristic of poplar-type propolis—flavonoid aglycones (pinocembrin, galangin, pinobanksin and pinobanskin-3-O-acetate) and hydroxycinnamic acid monoesters (mainly caffeic acid phenethyl ester and different isomers of caffeic acid prenyl ester). The second plant precursor of Kazakh propolis was aspen–poplar with 2-acetyl-1,3-di-p-coumaroyl glycerol as the main marker. Regarding antimicrobial activity, Kazakh propolis revealed stronger activity against reference Gram-positive strains (MIC from 31.3 to above 4000 mg/L) and yeasts (MIC from 62.5 to 1000 mg/L) than against reference Gram-negative strains (MIC ≥ 4000 mg/L). Moreover, Kazakh propolis showed good anti-Helicobacter pylori activity (MIC and MBC were from 31.3 to 62.5 mg/L). All propolis samples were also tested for H. pylori urease inhibitory activity (IC50, half-maximal inhibitory concentration, ranged from 440.73 to 11,177.24 µg/mL). In summary Kazakh propolis are potent antimicrobial agents and may be considered as a medicament in the future. [ABSTRACT FROM AUTHOR]

The root extracellular trap (RET) consists of root-associated, cap-derived cells (root AC-DCs) and their mucilaginous secretions, and forms a structure around the root tip that protects against biotic and abiotic stresses. However, there is little information concerning the changes undergone by the RET during droughts, especially for tree species. Morphological and immunocytochemical approaches were used to study the RET of black poplar (Populus nigra L.) seedlings grown in vitro under optimal conditions (on agar-gelled medium) or when polyethylene glycol-mediated (PEG6000—infused agar-gelled medium) was used to mimic drought conditions through osmotic stress. Under optimal conditions, the root cap released three populations of individual AC-DC morphotypes, with a very low proportion of spherical morphotypes, and equivalent proportions of intermediate and elongated morphotypes. Immunolabeling experiments using anti-glycan antibodies specific to cell wall polysaccharide and arabinogalactan protein (AGP) epitopes revealed the presence of homogalacturonan (HG), galactan chains of rhamnogalacturonan-I (RG-I), and AGPs in root AC-DC cell walls. The data also showed the presence of xylogalacturonan (XGA), xylan, AGPs, and low levels of arabinans in the mucilage. The findings also showed that under osmotic stress conditions, both the number of AC-DCs (spherical and intermediate morphotypes) and the total quantity of mucilage per root tip increased, whereas the mucilage was devoid of the epitopes associated with the polysaccharides RG-I, XGA, xylan, and AGPs. Osmotic stress also led to reduced root growth and increased root expression of the P5CS2 gene, which is involved in proline biosynthesis and cellular osmolarity maintenance (or preservation) in aerial parts. Together, our findings show that the RET is a dynamic structure that undergoes pronounced structural and molecular remodeling, which might contribute to the survival of the root tip under osmotic conditions. [ABSTRACT FROM AUTHOR]

The main purpose of this study was to evaluate the effect of hydrothermal treatment with boric acid impregnation on some physical and mechanical characteristics and fire resistance of poplar (Populus nigra) and radiata pine (Pinus radiata) wood. In this study, two times of 60 and 90 minutes with two temperatures of 150°C and 180°C were used for the hydrothermal treatment, and boric acid with the concentrations of 1, 3 and 5% dissolved in water was used for the impregnation treatment. The measurement of the bending strength, impact resistance, volumetric swelling and fire resistance (weight loss due to fire) were done using ASTM-D143, ASTM-D256, ASTM 4446-2002 and ISO 11925 testing procedure, respectively. On fire resistance, 5% boric acid treatment showed the least weight loss due to burning of two species. As a result of the hydrothermal treatment alone, the fire resistance was even lower than the control. In this regard, the combination of hydrothermal treatment with boric acid treatment resulted in results close to those of hydrothermal with boric acid treatment. Positive effect of hydrothermal treatment on the improvement of dimensional stability, is considered as one of the results of the present study. The temperature of 180°C with a time of 90 minutes reduced the swelling of poplar and radiata pine by about 36.8 and 42%, respectively. Regarding impact resistance, the effect of hydrothermal treatment on the wood of both species and the effect of boric acid treatment on radiata pine wood were negative. Hydrothermal treatment at a temperature of 180°C and with a time of 90 minutes decreased the impact resistance by 28.2% in the wood of both species, and 5% boric acid treatment caused a 13.3% decrease in this property in radiata pine wood. [ABSTRACT FROM AUTHOR]

SIMILAR TO RCD ONE (SRO) gene family is a small plant-specific gene family responsible for growth, development, and stress responses. In particular, it plays a vital role in responding to abiotic stresses such as salt, drought, and heavy metals. Poplar SROs are rarely reported to date. In this study, a total of nine SRO genes were identified from Populus simonii × Populus nigra, which are more similar to dicotyledon SRO members. According to phylogenetic analysis, the nine PtSROs can be divided into two groups, and the members in the same cluster have a similar structure. There were some cis-regulatory elements related to abiotic stress response and hormone-induced factors identified in the promoter regions of PtSROs members. Subcellular localization and transcriptional activation activity of PtSRO members revealed a consistent expression profile of the genes with similar structural profiles. In addition, both RT-qPCR and RNA-Seq results indicated that PtSRO members responded to PEG-6000, NaCl, and ABA stress in the roots and leaves of Populus simonii × Populus nigra. The PtSRO genes displayed different expression patterns and peaked at different time points in the two tissues, which was more significant in the leaves. Among them, PtSRO1c and PtSRO2c were more prominent in response to abiotic stress. Furthermore, protein interaction prediction showed that the nine PtSROs might interact with a broad range of transcription factors (TFs) involved in stress responses. In conclusion, the study provides a solid basis for functional analysis of the SRO gene family in abiotic stress responses in poplar. [ABSTRACT FROM AUTHOR]

Helicobacter pylori (H. pylori) is considered the most common bacterial pathogen colonizing stomach mucosa of almost half the world's population and is associated with various gastrointestinal diseases (from digestive problems and ulcers to gastric cancer). A lack of new drugs and a growing number of H. pylori antibiotic-resistant strains is a serious therapeutic problem.As a mixture of natural compounds, propolis has antimicrobial activity based on high concentrations of bioactive polyphenols (mainly flavonoids and phenolic acid derivates). The chemical composition of tested Georgian propolis is characterized by the presence of flavonoids aglycones, and phenolic acid monoesters, e.g., pinobanksin-5-methyl ether, pinobanksin, chrysin, pinocembrin, galangin, pinobanksin-3-O-acetate, pinostrobin and pinobanksin-3-O-butanoate, or isobutanoate and methoxycinnamic acid cinnamyl ester. The anti-H. pylori activity of 70% ethanol water extracts of 10 Georgian propolis samples was evaluated in vitro by MIC (minimal inhibitory concentration) against the reference strain (H. pylori ATCC 43504) and 10 clinical strains with different antibiotic-resistance patterns. The strongest anti-Helicobacter activity (MIC and MBC = 31.3 µg/mL) was observed for propolis from Orgora, Ota, and Vardzia and two from Khaheti. Lower levels of activity (MIC = 62.5 µg/mL) were found in propolis obtained from Qvakhreli and Pasanauri, while the lowest effect was observed for Norio and Mestia (MIC = 125.0 µg/mL). However, despite differences in MIC, all evaluated samples exhibited bactericidal activity. We selected the most active propolis samples for assessment of urease inhibition property. Enzyme activity was inhibited by propolis extracts, with IC50 ranging from 4.01 to 1484.8 µg/mL. Principal component analysis (PCA) and hierarchical fuzzy clustering (dendrograms) coupled with matrix correlation analysis exhibited that the strongest anti-Helicobacter activity was connected with black poplar origin and high flavonoid content of propolis. Samples with lower activity contained higher presence of aspen markers and/or dominance of non-flavonoid polyphenols over flavonoids. In summary, Georgian propolis can be regarded as a source bioactive compounds that can be used as adjuvant in therapy of H. pylori infection. [ABSTRACT FROM AUTHOR]

Dielectric sensors are a popular choice for determining wood moisture content. However, the output of these devices, especially when measuring high moisture content, may be significantly affected by the moisture content itself, by sensor frequency (f) and by environmental temperature (T). This study investigated the effect mechanism of f and T on dielectric properties of wood with different moisture contents. Dielectric constant (ε) and dielectric loss factor (tan δ) for Populus nigra, Tilia tuan, Abies fabri and Fraxinus mandshurica wood samples of various moisture contents were measured from 1 to 107 Hz and from – 40 to 25 °C. The results show that wood ε increases with increasing moisture content and temperature, and decreases with increasing f. The dielectric constant depends significantly on f when T exceeds 6 °C, the rate of ε decreases with increasing f. At room temperature, tan δ of wood with moisture content >50% were not related, and peaked between 103 and 104 Hz. The change of tan δ with T is complex. The results provide a basis for in-depth research on the dielectric properties of wood with high moisture content and a theoretical basis for the measurement and calibration of the moisture content of standing trees. [ABSTRACT FROM AUTHOR]

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The particle size of biochar is a vital parameter adjusting the soil CO2 production, whereas the effect of biochar addition with different particle sizeon soil CO2 production is still largely unclear. Furthermore, combined effects of biochar addition and temperature on CO2 production are still unknown. To address this gap, a series of incubation experiments were conducted to examine the single and interactive effects of biochar addition with three particle sizes (1–0.5 mm, 0.5–0.1 mm, and <0.1 mm) and temperature on CO2 production in a temperate forest, China. The soil samples were collected from a poplar (Populus nigra) forest in the sandy area of the ancient Yellow River in western Shandong Province, China. Cumulative CO2 production of fine-grained biochar addition (<0.1 mm) was 88.13–92.67% of that of coarse-grained biochar (1–0.5 mm). The addition of fine-grained biochar decreased CO2 production by reducing soil nitrogen availability (i.e., nitrate and ammonium) and increasing soil pH compared to the coarse-grained biochar. Biochar addition promoted the temperature sensitivity (Q10) of CO2 production by increasing the relative abundance of recalcitrant carbon fractions. Interactive effects of biochar addition and increasing temperature was synergistic due to the raising Q10 value of CO2 production. Our results highlight the importance of particle size of biochar on CO2 production, less particle size of biochar, the less CO2 production. We suggest that the simultaneous effect of biochar addition and temperature on CO2 production may be underestimated basing on their single effects. Our results suggest that <0.1 mm is a threshold value of biochar particle size that is helpful to soil carbon sequestration. [ABSTRACT FROM AUTHOR]