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Native ectomycorrhizal fungi (ECMF) are generally more effective than non-native ECMF in facilitating the phytoremediation of heavy metal (HM) ions from contaminated soils. This study aimed to investigate the contributions of four ECMF species—Suillus luteus, Suillus flavidus, Suillus variegatus, and Gomphidius glutinosus—that were isolated from mining areas to the growth, water status, photosynthesis, and metallothionein gene expression of Populus alba exposed to varying concentrations of lead (Pb). The experiment lasted two months and involved P. alba cuttings subjected to Pb concentrations of 0, 200, and 400 mg kg−1, representing no Pb stress, moderate Pb stress, and severe Pb stress, respectively. Results indicated that S. flavidus significantly enhanced the growth, water status, photosynthesis parameters, and metallothionein gene expression of P. alba under Pb stress, whereas S. luteus only exhibited positive effects under severe Pb stress. S. variegatus negatively affected the growth, water status, photosynthesis, and metallothionein gene expression of P. alba under Pb stress, while no significant difference was observed between the control treatment and G. glutinosus symbiosis. Therefore, S. flavidus and S. luteus are promising ECMF species for ecological restoration in mining areas, especially in P. alba woodlands. [ABSTRACT FROM AUTHOR]

Herbal plants have gained enormous interest due to their immune, antioxidant, and antibacterial activities. The present study proposed that white poplar (Populus alba) leave extract (WPE) might provide a promising alternative to traditional antibiotics to treat Aeromonas veronii infection in Nile tilapia (Oreochromis niloticus). WPE showed an in vitro antibacterial activity [22 ± 0.45 mm inhibition zone, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 60 µg/mL] against A. veronii. For the in-vivo study, a factorial (2 × 2) design was used to investigate the therapeutic effects of WPE on the antioxidant/immune status and blood biochemical parameters of Nile tilapia challenged with A. veronii. One-hundred sixty fish (33 ± 1.5 g) were assigned into four experimental groups, each with four replicates (4 glass tanks/group, 40 fish/group, 10 fish/tank) for 10 days. In the first (1st) and 2nd groups, 0 and 1.5 mg/L WPE were applied in tank water, respectively, without fish being challenged. In the 3rd and 4th groups, 0 and 1.5 mg/L WPE were applied in tank water, respectively, with fish intraperitoneal inoculated with 0.2 mL of A. veronii (0.5 × 107 CFU). Aeromonas veronii infection significantly diminished the survivability, hepatic catalase, lysozyme activity, nitric oxide, immunoglobulin M, phagocytic %, total protein, albumin, and globulin. Moreover, a significant rise in the hepatic malondialdehyde, serum hepatorenal function indicators, cortisol, and glucose levels were consequences of A. veronii challenge. Interestingly, the interaction between bacterial challenge and WPE application increased the survivability, antioxidant activity, and immune responses and reduced ALT levels of fish treated with WPE during the bacterial challenge. The serum creatinine, cortisol, and glucose levels were decreased in fish treated with WPE during the infection but still higher than in the non-infected fish either treated or not treated with WPE. In conclusion, WPE (1.5 mg/L) can be used as an antibacterial substance in fish farming to alleviate the detrimental impacts of A. veronii infection by enhancing the antioxidant/immune status of the infected fish. These outcomes could help reduce antibiotic usage in fish farms, which is conducive to the sustainable development of aquaculture. HIGHLIGHTS: White poplar extract (WPE) had an in vitro antibacterial activity against Aeromonas veronii. Aeromonas veronii infection inhibited the antioxidant/immune functions of Nile tilapia. Aeromonas veronii infection altered the hepatorenal functions and biochemical parameters of Nile tilapia. WPE at a level of 1.5 mg/L displayed a therapeutic effect in Nile tilapia against A. veronii. [ABSTRACT FROM AUTHOR]

The white poplar (Populus alba) is a dioecious woody plant with significant potential for the phytoremediation of soils. To realize this potential, it is necessary to utilize growth-promoting microorganisms. One potential source of such beneficial microorganisms is the rhizosphere community of wild-growing trees. However, the structure, dynamics, and metabolism of the rhizosphere community of wild-growing white poplar remain poorly understood. To ascertain seasonal dynamics, species diversity, and metabolic potential, we sequenced 16S rRNA genes in metagenomes derived from 165 soil samples collected in spring and autumn from the root surfaces of 102 trees situated in disparate geographical locations. The three most prevalent phyla across all samples are Proteobacteria, Actinobacteriota, and Acidobacteriota. At the order level, the most prevalent orders are Sphingomonadales and Rhizobiales. Accordingly, the families Sphingomonadaceae and Rhizobiaceae were identified as dominant. The rhizospheric microbiome exhibited substantial inter-seasonal variation. Six families, including Caulobacteraceae, Xanthomonadaceae, Chitinophagaceae, Chthoniobacteraceae, Sphingomonadaceae, and Rhizobiaceae, exhibited alterations (spring-to-autumn) across all geographical locations under study. Members of the Rhizobiaceae family, which includes nitrogen-fixing bacteria, can provide poplar with plant-available forms of nitrogen such as nitrate and ammonium. The rhizosphere microbiome may facilitate the conversion of inorganic sulfur into sulfur-containing amino acids, cysteine and methionine, that are bioavailable to plants. Furthermore, the rhizosphere microbiome is capable of synthesizing amino acids, organic acids (including Krebs cycle acids), and some lipids and sugars. Consequently, the rhizosphere community can stimulate poplar growth by providing it with readily available forms of nitrogen and sulfur, as well as building blocks for the synthesis of proteins, nucleic acids, and other macromolecules. Many of these pathways, including nitrogen fixation, were subjected to seasonal changes. [ABSTRACT FROM AUTHOR]

[Objective] To reveal the regional variation of adaptation strategies of common species Populus alba, it can provide data support for predicting plant adaptation potential under the background of climate change. [Methods] Nine state-owned forest farms were selected along the precipitation gradient from southeast to northwest China, and 18 functional traits related to water and carbon status of the common species P . alba were measured. The methods of trait network and principal component analysis were used to quantify the regional differentiation of traits, and to clarify the main climatic factors driving the variation of traits and their habitat adaptation strategies. [Results] (1) The average coefficient of variation of each trait was 12.09%-60.35%, and the variation level of photosynthetic physiology and stomatal related traits was generally higher than that of other traits. (2) The importance percentage of photosynthetic active radiation, growing season mean temperature, annual mean precipitation, and aridity index on trait variation were 35.45%, 28.37%, 19.36%, and 16.93%, respectively. Among them, photosynthetic active radiation in the growing season was the most important climatic factor driving trait variation. (3) The central trait of the trait network was the maximum net photosynthetic rate. [Conclusion] There are differences in the adaptation strategies of P . alba in the precipitation gradient zone. From the humid/semi-humid region to the arid region, the carbon economy strategy changes from a relatively conservative type to an acquisition type.

The article in the Plant Biotechnology Journal discusses the genome and CRISPR/Cas9 system of the widespread forest tree Populus alba. Populus trees are essential for the Earth's biomass and provide various resources for humans. The study focuses on the genetic characteristics of Populus alba, its distribution, adaptability, and potential as a research system for tree biology. The research presents a new genome assembly of Populus alba v2.0, highlighting its completeness and continuity compared to the previous version. Additionally, the article describes an optimized genetic transformation method for Populus alba, which can aid in functional research. [Extracted from the article]

The enormous quantities of fly ash (FA) produced by thermal power plants is a global problemand safe, sustainable approaches to reduce the amount and its toxic effects are still being sought. Vegetation cover comprising long-living species can help reduce FA dump-related environmental health issues. However, the synergistic effect of multiple abiotic factors, like drought, low organic matter content, a deficit of essential nutrients, alkaline pH, and phytotoxicity due to high potentially toxic element (PTE) and soluble salt content, limits the number of species that can grow under such stressful conditions. Thus, we hypothesised that Populus alba L., which spontaneously colonised two FA disposal lagoons at the 'Nikola Tesla A' thermal power plant (Obrenovac, Serbia) 3 years (L3) and 11 years (L11) ago, has high restoration potential thanks to its stress tolerance. We analysed the basic physical and chemical properties of FA at different weathering stages, while the ecophysiological response of P. alba to multiple stresses was determined through biological indicators [the bioconcentration factor (BCF) and translocation factor (TF) for PTEs (As, B, Cr, Cu, Mn, Ni, Se, and Zn)] and by measuring the following parameters: photosynthetic efficiency and chlorophyll concentration, nonenzymatic antioxidant defence (carotenoids, anthocyanins, and phenols), oxidative stress (malondialdehyde (MDA) concentrations), and total antioxidant capacity (IC50) to neutralise DPPH free radical activity. Unlike at L3, toxic As, B, and Zn concentrations in leaves induced oxidative stress in P. alba at L11, shown by the higher MDA levels, lower vitality, and reduced synthesis of chlorophyll, carotenoids, and total antioxidant activity, suggesting its stress tolerance decreases with long-term exposure to adverse abiotic factors. Although P. alba is a fast-growing species with good metal accumulation ability and high stress tolerance, it has poor stabilisation potential for substrates with high As and B concentrations, making it highly unsuitable for revitalising such habitats. [ABSTRACT FROM AUTHOR]

Fine roots are the most dynamic and physiologically active components of belowground tree organs. However, much remains unknown regarding the changes in fine root morphological characteristics during mycorrhizal colonization, especially in natural sites. The aim of this study was to analyze seasonal heterogeneity in fine roots and the mycorrhizal colonization of mature white poplar (Populus alba L.) trees under different soil conditions. Two floodplain forests were selected in Central Europe (Poland), which differed in soil moisture and structure. Fine roots were sampled during one growing season from the upper soil layer. Poplars were characterized by dual mycorrhizal colonization on one root system. It was, therefore, possible to investigate the contribution of two mycorrhizal types (arbuscular mycorrhiza—AM; and ectomycorrhiza—ECM) in response to different habitat conditions. The season was shown to be significant for all fine root features, as well as the degree of mycorrhizal colonization. Roots were better adapted to a drier habitat with a greater proportion of sand, mainly due to a reduction in the fine root diameter (FRD), while other root characteristics did not differ significantly. The degree of mycorrhizal colonization (RLC) and the proportion of arbuscular mycorrhizal structures (AM) were significantly and negatively correlated with the soil water content. A mutual competition between arbuscular mycorrhizas and ectomycorrhizas for poplar roots was also observed, particularly with respect to the season, site, and soil moisture. Changing environmental conditions (especially soil moisture) contribute not only to the morphological and functional changes of fine roots but also to changes in the proportion of arbuscular mycorrhiza and ectomycorrhiza. Understanding the mechanisms of adaptation of tree roots to changing environmental conditions is especially important in the context of climate change. [ABSTRACT FROM AUTHOR]

The enormous quantities of fly ash (FA) produced by thermal power plants is a global problem and safe, sustainable approaches to reduce the amount and its toxic effects are still being sought. Vegetation cover comprising long-living species can help reduce FA dump-related environmental health issues. However, the synergistic effect of multiple abiotic factors, like drought, low organic matter content, a deficit of essential nutrients, alkaline pH, and phytotoxicity due to high potentially toxic element (PTE) and soluble salt content, limits the number of species that can grow under such stressful conditions. Thus, we hypothesised that Populus alba L., which spontaneously colonised two FA disposal lagoons at the ‘Nikola Tesla A’ thermal power plant (Obrenovac, Serbia) 3 years (L3) and 11 years (L11) ago, has high restoration potential thanks to its stress tolerance. We analysed the basic physical and chemical properties of FA at different weathering stages, while the ecophysiological response of P. alba to multiple stresses was determined through biological indicators [the bioconcentration factor (BCF) and translocation factor (TF) for PTEs (As, B, Cr, Cu, Mn, Ni, Se, and Zn)] and by measuring the following parameters: photosynthetic efficiency and chlorophyll concentration, non-enzymatic antioxidant defence (carotenoids, anthocyanins, and phenols), oxidative stress (malondialdehyde (MDA) concentrations), and total antioxidant capacity (IC50) to neutralise DPPH free radical activity. Unlike at L3, toxic As, B, and Zn concentrations in leaves induced oxidative stress in P. alba at L11, shown by the higher MDA levels, lower vitality, and reduced synthesis of chlorophyll, carotenoids, and total antioxidant activity, suggesting its stress tolerance decreases with long-term exposure to adverse abiotic factors. Although P. alba is a fast-growing species with good metal accumulation ability and high stress tolerance, it has poor stabilisation potential for substrates with high As and B concentrations, making it highly unsuitable for revitalising such habitats.

Cell division plays an indispensable role in leaf morphogenesis, which is regulated via the complexes formed by cyclin and cyclin-dependent kinase (CDK). In this study, gene family analysis, exogenous auxin stimulation, RNA-seq and WGCNA analysis were all used to investigate the molecular mechanisms by which cell-cycle-related factors participated in the auxin signaling pathway on leaf morphogenesis. Sixty-three cyclin members and seventeen CDK members in Populus alba were identified and systematically analyzed. During the evolution, WGD was the main reason that resulted in the expansion of cyclin and CDK genes. Firstly, after a short time treating with auxin to matured leaves of seedlings, genes related to cell division including GRF and ARGOS were both upregulated to restart the transition of cells from G1-to-S phase. Secondly, with three days of continuous auxin stimulation to leaves at different developmental stages, leaves area variation, transcriptomes and hormones were analyzed. By PCA, PCoA and WGCNA analyses, the turquoise module was both positively related to leaf development and auxin. Based on the co-expression analysis and Y2H experiment, PoalbCYCD1;4, PoalbCYCD3;3 and PoalbCYCD3;5 were supposed to interact with PoalbCDKA;1, which could be the trigger to promote the G1-to-S phase transition. The ARF transcription factor might play the key role of connecting the auxin signaling pathway and cell division in leaf morphogenesis by affecting CYC–CDK complexes. [ABSTRACT FROM AUTHOR]

Abstract Cationic cell-wall-bound peroxidase (CWPO-C) from Populus alba is the only Class III peroxidase that has been shown to be able to oxidize high molecular weight lignin polymers from sinapyl alcohol and previously, has been believed to be a lignin polymerization-specific peroxidase. However, using an Arabidopsis heterologous expression system, we showed recently that CWPO-C contributes to differentiation or early growth and is involved in auxin catabolism. In this study, to clarify the function of CWPO-C in poplar, we analyzed CWPO-C gene expression and phenotypic changes with CWPO-C overexpression and suppression. Real-time PCR and monitoring promoter activity of CWPO-C using β-glucuronidase (GUS) assay revealed that CWPO-C was strongly expressed in immature tissues, such as the upper stem, axillary buds, and young leaves, in addition to expression in developing xylem. In transgenic poplars in which the expression of CWPO-C was upregulated or suppressed, changes in stem growth, gravitropism bending time, lignin content and syringyl/guaiacyl (S/G) composition were observed. Overexpressing CWPO-C enhanced stem growth and gravitropic response (shorter bending time). With suppressed CWPO-C expression, the lignin content was reduced approximately 45% and the S/G ratio decreased by half. These results strongly suggest that CWPO-C plays a role in differentiation and early growth, as well as in lignin polymerization.

Aeolesthes sarta or Trirachys sarta is a polyphagous long-horned beetle that has caused severe damage to the Populus alba forests/plantations in its regions of origin. Climate change could accelerate the introduction and spread of invasive pest species, potentially causing ecological damage and economic losses. Furthermore, globalization and increased trade can inadvertently transport pests across borders into regions where they do not already occur. Hence, it is crucial to identify areas where the climate is most suitable for the establishment of A. sarta's and which areas of the world are suitable for the growth of P. alba under climate change scenarios. This study employed the CLIMEX model to estimate the potential global distribution of A. sarta and its correlation with its dominant host, P. alba, under current climatic conditions and potential future scenarios, namely the A1B and A2 climate change scenarios (CCSs). Under current climatic conditions, the model indicates that the establishment of a climatically suitable habitat for A. sarta extends beyond its current known range. The model estimated that, under the world's current climatic conditions, 41.06% of the world can provide suitable areas (EI > 0) for the survival of A. sarta. For P. alba, under the current climatic conditions, suitable regions for the growth of P. alba are present in all continents (excluding Antarctica); under the world's current climatic conditions, 53.52% of the world can provide suitable areas for the growth of P. alba (EI > 0). Climate change will significantly alter the number of suitable habitats for A. sarta development and P. alba growth globally. In future climatic conditions, the number areas capable of supplying suitable habitats (EI > 0) for A. sarta will slightly decrease to 40.14% (under A1B and A2 CCSs), while, for P. alba, the number areas capable of supplying suitable habitats will also marginally decrease to 50.39% (under A1B scenario), and this figure is estimated to drop to 48.41% (under A2 scenario) by the end century (2100). Asia, Europe, North America, South America, and Oceania have a high percentage of highly suitable areas for A. sarta development and P. alba growth under current climatic conditions; however, according to estimates of future climatic conditions, by the end century, only Asia, Europe, North America, and Oceania will have a high percentage of highly suitable areas for A. sarta development and P. alba growth. The range of highly suitable habitats is likely to increase in the northern hemisphere; however, this range is expected to shrink with regards to the southern hemisphere. The range contraction was higher under the A2 climate change scenario due to a higher warming trend than in the A1B scenario. Due to climate change, the range of A. sarta development shifted, as did the P. alba growth range, which, thanks to the suitable environmental conditions for the growth of P. alba, makes all those regions vulnerable to the introduction and development of A. sarta. Strict monitoring, prevention, and control measures at borders, airports, and seaports before the trade of P. alba and other suitable host species wood (logs/billets) are highly recommended to prevent the spread of A. sarta and ensure biodiversity security. It is expected that the A. sarta and P. alba climate models presented here will be useful for management purposes since both can be adapted to guide decisions about imparting resources to regions where the threat of pest invasion remains and away from regions where climate suitability is predicted to decrease in the future. [ABSTRACT FROM AUTHOR]

Infections caused by pathogenic bacteria are a recurrent problem in the livestock sector, generating important economic losses in the livestock industry. One of the main strategies includes antibiotic therapy; however, its use is limited since pathogenic bacteria present resistance to these drugs, which makes treatment against microbial infections difficult. Therefore, the hypothesis proposed was that ethanolic extracts of native plants from the state of Sonora, Mexico, can inhibit the growth of Gram (+) and Gram (-) pathogenic bacteria related to common infections in the livestock industry. The objective was to evaluate the phytochemical and antimicrobial profile of native plants from the state of Sonora, Mexico. In this study, 17 ethanolic extracts were obtained from native plants of Sonora, and the antimicrobial activity was evaluated by the agar diffusion method and by the microdilution technique using reference bacteria from the ATCC collection. The phytochemical profile was evaluated by spectrophotometry and the experimental design used was completely randomized with three replicates per treatment at 95 % confidence. The results showed that extracts of Prosopis velutina, Ibervillea sonorae, Populus alba, Ambrosia ambrosioides, Krameria sonorae, and Leucaena leucocephala were effective in eliminating Listeria monocytogenes ATCC 19115, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Salmonella enterica serovar Typhimurium ATCC 14028 (p = 0.05). In addition, these extracts presented the highest concentration of total polysaccharides, flavones and flavonols, flavanones and dihydroflavonols, tannins and total chlorogenic acid (p = 0.05). Therefore, plant extracts from Sonora, Mexico, represent a natural alternative for the control of Gram (+) and Gram (-) pathogens of importance to the livestock industry. [ABSTRACT FROM AUTHOR]

In this study, the effect of irrigation with municipal effluent on performance of two clones of Populus alba after one year growth was investigated. The test was done in a completely randomized design with two factors: 1) soil in two levels and 2) poplar clones in two levels. After one year growth, in both poplar clones, significant increase (P ≤ 0.01) in growth and biomass parameters of plants treated by soil irrigated with municipal effluent was observed with the highest values in P. alba 44/13 clone. Also, in both poplar clones, treatment of plants with soil affected by municipal effluent resulted in significant increase (P ≤ 0.01) of nutrient and heavy metal concentration in plant organs compared to control plants. In both poplar clones, the highest uptake and accumulation of Fe, Cu, Ni, Cr and Pb were in the roots and Zn and Mn in the leaves. The effect of clone on the uptake and accumulation of most micronutrients and heavy metals was significant (P ≤ 0.05). In general, the plants of P. alba 20/45 accumulated higher amounts of micronutrients and heavy metals in plant organs. The results of the present study showed that after one year growth, P. alba 44/13 clone had better growth performance and biomass production and P. alba 20/45 clone demonstrated higher uptake and accumulation potential of most micronutrients and heavy metals in plant organs. In general, due to good performance of two studied poplar clones, both poplar clones can be considered for wood farming in lands affected by municipal effluent.

The ability to modulate photosynthesis is essential for plants to adapt to fluctuating growing conditions. Populus species show high tolerance to various and highly variable environments. To understand their response strategies against fluctuating environments, this study investigated the morphological and physiological differences of white poplar (Populus alba) leaves when grown in a phytotron, glasshouse, and field. Our results show that the palisade cells were elongated in the field, which would enhance intercellular CO2 exchange. Photosynthetic capacity was the highest in the field leaves, as shown by higher electron transport rates (1.8 to 6.5 times) and carbon assimilation rates (2.7 to 4.2 times). The decrease of PSI acceptor-side limitation and increase of PSI donor-side limitation suggests changes in PSI redox status may contribute to photoprotection. This plasticity of white poplar allows adjusting its structure and photosynthesis under fluctuating conditions, which may partly enable its outstanding tolerance against environmental changes.

Cationic cell-wall-bound peroxidase (CWPO-C) from Populus alba is the only Class III peroxidase that has been shown to be able to oxidize high molecular weight lignin polymers from sinapyl alcohol and previously, has been believed to be a lignin polymerization-specific peroxidase. However, using an Arabidopsis heterologous expression system, we showed recently that CWPO-C contributes to differentiation or early growth and is involved in auxin catabolism. In this study, to clarify the function of CWPO-C in poplar, we analyzed CWPO-C gene expression and phenotypic changes with CWPO-C overexpression and suppression. Real-time PCR and monitoring promoter activity of CWPO-C using β-glucuronidase (GUS) assay revealed that CWPO-C was strongly expressed in immature tissues, such as the upper stem, axillary buds, and young leaves, in addition to expression in developing xylem. In transgenic poplars in which the expression of CWPO-C was upregulated or suppressed, changes in stem growth, gravitropism bending time, lignin content and syringyl/guaiacyl (S/G) composition were observed. Overexpressing CWPO-C enhanced stem growth and gravitropic response (shorter bending time). With suppressed CWPO-C expression, the lignin content was reduced approximately 45% and the S/G ratio decreased by half. These results strongly suggest that CWPO-C plays a role in differentiation and early growth, as well as in lignin polymerization. [ABSTRACT FROM AUTHOR]

Fine roots are a key component of carbon turnover in the terrestrial environment. Therefore, their distribution allows for the estimation of areas of carbon in the soil. The vertical distribution of roots is the result of both the tree species and various environmental factors. Research on the architecture of root systems most often includes seedlings and young trees growing under experimental conditions; however, little is known about trees in their natural habitats. The aim of this study is to analyze the fine root distribution of mature white poplar trees in natural riverside temperate zone forests of Central Europe (Poland) periodically flooded and in dry hydrological conditions. The length, diameter, and area of the fine roots, as well as the specific root length (SRL) and specific root area (SRA) of white poplar were measured in three layers of the soil, 0–10 cm, 10–20 cm, and 20–30 cm depths, in three forest sites. Two of the sites experience periodic floods, and one has been without flooding for 80 years, due to the construction of a flood embankment. The highest values of the lengths and surface areas of the poplar fine roots were observed at a depth of 0–10 cm at all sites. Soil moisture was positively correlated with the analyzed root parameters. The presence of understory plant roots contributed to the reduction in the fine root length of poplar in the subsurface layer, compared to the site that was not affected by the presence of plants other than poplar. The distribution of fine roots, the most dynamic part of the plant root system, reflects the most active areas in the soil profile. The presented research will allow for a better understanding of the functioning of natural riverside ecosystems, as well as show the great adaptability of white poplar fine roots to various conditions in the soil. [ABSTRACT FROM AUTHOR]

The presence of antimony (Sb) in high concentrations in the environment is recognized as an emerging problem worldwide. The toxicity of Sb in plant tissues is known; however, new methods of plant tolerance improvement must be addressed. Here, poplar callus (Populus alba L. var. pyramidallis) exposed to Sb(III) in 0.2 mM concentration and/or to silicon (Si) in 5 mM concentration was cultivated in vitro to determine the impact of Sb/Si interaction in the tissue. The Sb and Si uptake, growth, the activity of superoxide dismutase (SOD), catalase (CAT), guaiacol-peroxidase (G-POX), nutrient concentrations, and the concentrations of photosynthetic pigments were investigated. To elucidate the action of Si during the Sb-induced stress, the impact of short and long cultivations was determined. Silicon decreased the accumulation of Sb in the calli, regardless of the length of the cultivation (by approx. 34%). Antimony lowered the callus biomass (by approx. 37%) and decreased the concentrations of photosynthetic pigments (up to 78.5%) and nutrients in the tissue (up to 21.7%). Silicon supported the plant tolerance to Sb via the modification of antioxidant enzyme activity, which resulted in higher biomass production (increased by approx. 35%) and a higher uptake of nutrients from the media (increased by approx. 10%). Silicon aided the development of Sb-tolerance over the longer cultivation period. These results are key in understanding the action of Si-developed tolerance against metalloids. [ABSTRACT FROM AUTHOR]

Solving the problem of global climate change requires an integrated approach, including the use of the phytochorological method. Remote sensing is the best option for monitoring changes in the boundaries of plant ranges. However, the problem of species identification based on RS data has not yet been solved. Therefore, the aim of the study was to assess the possibility of using vegetation indices (VIs) calculated from the data of hyperspectral imaging (HSI) of crowns of woody plants to determine their species. The objects of the study were samples of the species Populus tremula L., P. alba L., P. simonii Carriere. The survey was carried out with a Cubert UHD-185 hyperspectral camera in five periods with an interval of 7–10 days. 80 VIs were calculated. Sample sets were analyzed using Analysis of Variance (ANOVA), Principal component analysis (PCA), Decision Tree (DT) and Random Forest (RF) methods. The PCA and RF methods consistently distinguish all three species from each other throughout all five periods of the experiment. The most informative VIs are: Double Peak Index (DPI), Derivative index 1 (D1), Datt index 3 (Datt3) and Vogelmann index (Vogelmann).

Populus alba (P. alba) is a widespread tree species. An analysis of five mature P. alba, two from Quetta (Balochistan province) and three from Faisalabad (Punjab province) Pakistan, showed all to be infected by the monopartite begomovirus Tomato leaf curl Kerala virus (ToLCuKeV) and the alphasatellite Ageratum enation alphasatellite. Additionally, one P. alba was found to be infected with another monopartite begomovirus, Papaya leaf curl virus (PaLCuV), two with cotton leaf curl Multan alphasatellite and three with cotton leaf curl Multan betasatellite. Analysis of the sequences of full-length clones of each component showed them unchanged from published sequences and closely related to isolates identified in hosts other than P. alba, except for the PaLCuV isolate which proved to be a new strain of the virus. A Southern blot analysis showed replication of ToLCuKeV in P. alba ruling out the findings being due to contamination. This is the first report of the infection of mature P. alba trees by begomoviruses in association with satellites. The significance of these findings are discussed. [ABSTRACT FROM AUTHOR]

This study was carried out to study the performance of two-year old plants from two Populus alba clones in soil irrigated by municipal effluent. For this purpose, a pot experiment was done in a completely randomized design with two factors: 1) soil in two levels of irrigations and 2) two clones of poplar. In both poplar clones, after two growth seasons, significant increase of growth properties, leaf area, biomass and uptake and accumulation of micro and macro nutrients and also heavy metals in organs (root, stem and leaf) of plants irrigated by municipal effluent were observed compared to plants of control treatment. In both poplar clones, the highest uptake and accumulation of Fe, Cu, Ni, Cr and Pb were measured in the roots and Zn and Mn in the leaves. After two growth seasons, the two poplar clones did not demonstrate significant differences in terms of growth and biomass parameters, however the effect of clone on uptake and accumulation of micro nutrients and heavy metals in plant organs was significant. The highest amounts of most micronutrients and heavy metals were determined in plants of P. alba 20/45 treated by municipal effluent. Tolerance Index of both poplar clones in soil affected by municipal effluent after two growth seasons was above 100% and the effect of clone on this Index was not significant. Due to the good performance of two-year-old plants of P. alba in soil irrigated by municipal effluent, these poplar clones can be considered for wood farming in soil under municipal effluent irrigation. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is an essential macronutrient for plant growth. In deciduous trees, P is remobilized from senescing leaves and stored in perennial tissues during winter for further growth. Annual internal recycling and accumulation of P are considered an important strategy to support the vigorous growth of trees. However, the pathways of seasonal re‐translocation of P and the molecular mechanisms of this transport have not been clarified. Here we show the seasonal P re‐translocation route visualized using real‐time radioisotope imaging and the macro‐ and micro‐autoradiography. We analysed the seasonal re‐translocation P in poplar (Populus alba. L) cultivated under 'a shortened annual cycle system', which mimicked seasonal phenology in a laboratory. From growing to senescing season, sink tissues of 32P and/or 33P shifted from young leaves and the apex to the lower stem and roots. The radioisotope P re‐translocated from a leaf was stored in phloem and xylem parenchyma cells and redistributed to new shoots after dormancy. Seasonal expression profile of phosphate transporters (PHT1, PHT5 and PHO1 family) was obtained in the same system. Our results reveal the seasonal P re‐translocation routes at the organ and tissue levels and provide a foothold for elucidating its molecular mechanisms. Summary Statement: The phosphorus re‐translocation routes in Populus alba were visualized and gene expression of Pi transporters was analysed, using a shortened annual cycle system. Sink tissues of P shifted from young leaves to the stem and roots during senescence and stored P were reused for next spring growth. [ABSTRACT FROM AUTHOR]

The ability to modulate photosynthesis is essential for plants to adapt to fluctuating growing conditions. Populus species show high tolerance to various and highly variable environments. To understand their response strategies against fluctuating environments, this study investigated the morphological and physiological differences of white poplar (Populus alba) leaves when grown in a phytotron, glasshouse, and field. Our results show that the palisade cells were elongated in the field, which would enhance intercellular CO2 exchange. Photosynthetic capacity was the highest in the field leaves, as shown by higher electron transport rates (1.8 to 6.5 times) and carbon assimilation rates (2.7 to 4.2 times). The decrease of PSI acceptor-side limitation and increase of PSI donor-side limitation suggests changes in PSI redox status may contribute to photoprotection. This plasticity of white poplar allows adjusting its structure and photosynthesis under fluctuating conditions, which may partly enable its outstanding tolerance against environmental changes. [ABSTRACT FROM AUTHOR]

Populus alba is a large woody deciduous plant. The plant has been introduced to shooting, then multiplication of rooting on Murashige and Skoog (MS) medium. This work was designed to estimate the effect of two factors (low levels of 1-Naphthaleneacetic acid NAA and sucrose) on P. alba response resulting in 6 treatments compared to the control, with twelve measured responses. There was a significant difference in some measurements in morphology, like plantlets fresh-weight, shoot-, root-length, and leaf number. In the physiological measurements, there were significant differences in all the measured parameters. The low concentrations of sucrose and media composition/power (MS grams/L) led to starvation in plants; however, these conditions led to enhancement in some morphological and physiological parameters to overcome the starvation effect, compared to the control. The RAPD-PCR molecular marker (four decamers) was used to evaluate the new individuals' genetic variation (instability), resulting in a total polymorphism percentage of 50.83%. It was formerly known that the plantlets were identical to each other and to the mother plant. In this study, however, the use of distinct media power, hormonal and sucrose levels resulted in molecular variation reflected in P. alba's morphological and physiological responses. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the differences between juvenile and mature woods of Populus alba trees in the axial and radial directions of the stem. For this purpose, three stands of P. alba trees were randomly chosen and cut from at their diameter at breast height. Three disks with a thickness of 5 cm were taken at three different height levels along the tree stems. The specimens were sequentially cut in the radial position according to the ISO standards method. The results indicated that there are significant differences in the physical and biometric features of P. alba trees in the longitudinal and radial axes of the stem. As the height from the base of the tree to the top of the stem increased, the oven-dry density, basic density, and fiber biometric factors decreased. Moreover, as the distance from the pith to the bark increased, the oven-dry density, basic density, and fiber biometric factors increased. The microscopic study represented that the P. alba is a semi-ring-porous hardwood with distinct growth ring boundaries, simple perforation, homogenous rays, and alternative inter-vessel pits. [ABSTRACT FROM AUTHOR]

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The presence of antimony (Sb) in high concentrations in the environment is recognized as an emerging problem worldwide. The toxicity of Sb in plant tissues is known; however, new methods of plant tolerance improvement must be addressed. Here, poplar callus (Populus alba L. var. pyramidallis) exposed to Sb(III) in 0.2 mM concentration and/or to silicon (Si) in 5 mM concentration was cultivated in vitro to determine the impact of Sb/Si interaction in the tissue. The Sb and Si uptake, growth, the activity of superoxide dismutase (SOD), catalase (CAT), guaiacol-peroxidase (G-POX), nutrient concentrations, and the concentrations of photosynthetic pigments were investigated. To elucidate the action of Si during the Sb-induced stress, the impact of short and long cultivations was determined. Silicon decreased the accumulation of Sb in the calli, regardless of the length of the cultivation (by approx. 34%). Antimony lowered the callus biomass (by approx. 37%) and decreased the concentrations of photosynthetic pigments (up to 78.5%) and nutrients in the tissue (up to 21.7%). Silicon supported the plant tolerance to Sb via the modification of antioxidant enzyme activity, which resulted in higher biomass production (increased by approx. 35%) and a higher uptake of nutrients from the media (increased by approx. 10%). Silicon aided the development of Sb-tolerance over the longer cultivation period. These results are key in understanding the action of Si-developed tolerance against metalloids.

White poplar is a key species in wood production and afforestation, but also very important for biodiversity preservation and habitat improvement. Vegetative propagation from hardwood cuttings is the most desirable method of white poplar breeding. The present research analyzed the effect of various technological treatments on four white poplar clones. Selected treatments were powder formulations of indole butyric acid (IBA) and foliar treatment with urea. The variability of 14 morphometric characteristics on the rooting of cuttings was analyzed, as well as relationships between them. Differences in analyzed morphometric characteristics depended on genotype, while the effect of the examined technological treatments was detected only by Fisher’s least significant difference (LSD) test. Significant variability between genotypes was found for traits describing rooting at the basal cut (R0 and R0p), the number of leaves (LN), the total number of roots (TRN), and cutting survival in the first part of the growing season (SURV07). Application of IBA had significant stimulating effects on rooting at the lower part of cuttings (R05) compared to controls. Variability between genotypes after foliar treatment with urea was not detected. The examined parameters were grouped into 5 groups by principal component analysis, where shoot traits and traits that describe rooting at the basal cut were in the same group with total number of roots, and cutting survival (SURV07) was in a separate group. These results suggest a need for further testing of the characteristics of hardwood cuttings in white poplars. More efficient clone technology is needed, using auxins and/or nitrogen fertilization designed to suit the specific requirements of particular clones. [Projects of the Serbian Ministry of Education, Science and Technological Development, Grant no. 43007: Studying climate change and its influence on the environment: impacts, adaptation and mitigation and Grant. no 43002: Biosensing Technology and Global Systems for Continuous Research and Integrated Management of Ecosystems]

This study evaluates in vitro tolerance of white poplar genotypes to the presence of lead in an acidic rooting medium. Lead was supplemented in form of Pb(NO3)2, in the following concentrations: 0 M (Control), 10-6 M, 10-5 M, 10-4 M and 10-3 M. After four weeks of cultivation, the following characters were measured: number of roots, the length of the longest root, the shoot height, dry root mass and dry shoot mass, and parameters related to photosynthetic pigments: content of chlorophyll a, b, a+b, and of carotenoids in fresh mass, as well as chlorophyll a/b ratio. For further statistical analysis, tolerance indices by Turner and Marshal (TI) were calculated for each measured character. The strongest inhibitory effect was achieved on the medium with 10-4 M Pb(NO3)2, but the best differentiation between genotypes was achieved on the medium with 10-5 M Pb(NO3)2. The highest tolerance indices for the length of the longest root and shoot height had genotypes L-12 and LBM, and for root and shoot dry mass genotypes LCM and L-12. There were no significant differences between genotypes in tolerance indices by any of the examined photosynthetic parameters. The obtained results suggest that both low pH and the presence of citric acid as chelating agent improved evaluation of lead tolerance in comparison with the results obtained on media with standard pH and without citric acid in similar studies. In vitro tests on acidic medium with citric acid can efficiently differentiate examined genotypes for lead tolerance, which could be important for their use in phytoextraction projects, especially on acidic soils.

Researches were conducted on a 70 years old seed plantation of Bald cypress (Taxodium distichum) established on the habitat of White poplar and White willow (Salicion albae) and in natural forest of White poplar. As a result of chemical changes of organic material that comes to the land surface as a leaf waste, there are many changes as for the number of microorganisms and that caused some changes in their relations related to the soil in a natural forest of White poplar (Populus alba). It affected changes in soil characteristics with the increased relation between carbon and nitrogen, then with the increased content of humus, decreased acidity of the soil and increased content of available forms of phosphorus and potassium. [ABSTRACT FROM AUTHOR]

Main conclusion: Transgenic Arabidopsis thaliana and Populus alba plants overexpressing the zinc transporter ScZRC1 in shoots exhibit Zn tolerance. Increased Zn concentrations were observed in shoots of P. alba, a species suitable for phytoremediation. Genetic engineering of plants for phytoremediation is worth to consider if genes leading to heavy metal accumulation and tolerance are expressed in high biomass producing plants. The Saccharomyces cerevisiae ZRC1 gene encodes a zinc transporter which is primarily involved in the uptake of Zn into the vacuole. The ZRC1 gene was expressed in the model species A. thaliana and P. alba (cv. Villafranca). Both species were transformed with constructs carrying ScZRC1 under the control of either the CaMV35S promoter for constitutive expression or the active promoter region of the tobacco Rubisco small subunit (pRbcS) to limit the expression to the above-ground tissues. In hydroponic cultures, A. thaliana and poplar ScZRC1-expressing plants accumulated more Zn in vegetative tissues and were more tolerant than untransformed plants. No differences were found between plants carrying the CaMV35::ScZRC1 or pRbcS::ScZRC1 constructs. The higher Zn accumulation in transgenic plants was accompanied by an increased superoxide dismutase (SOD) activity, indicating the activation of defense mechanisms to prevent cellular damage. In the presence of cadmium in addition to Zn, plants did not show symptoms of metal toxicity, neither in hydroponic cultures nor in soil. Zn accumulation increased in shoots, while no differences were observed for Cd accumulation, in comparison to control plants. These data suggest that ectopic expression of ScZRC1 can increase the potential of poplar for the remediation of Zn-polluted soils, although further tests are required to assay its application in remediating multimetal polluted soils. [ABSTRACT FROM AUTHOR]

Aims: Methane (CH4) and nitrous oxide (N2O) fluxes from tree stems are still poorly quantified in temperate floodplain forests. Methods: Methane and N2O fluxes were repeatedly measured at 0.3, 1.6 and 3.6 m stem height at three sites along a landscape gradient ranging from non-flooded to frequently flooded forest sites. The non-flooded forest was dominated by Fraxinus excelsior and the infrequently and frequently flooded sites by Populus alba. Results: Stem surfaces were net CH4 and N2O sources at all sites. The CH4 source strength increased towards the wetter sites (non-flooded 2.51±12.71, infrequently-flooded 5.2±17.26, and frequently-flooded 11.15±24.04 μg-C-m−2 h−1), but flooding had no immanent effects on CH4 and N2O fluxes. Methane fluxes from poplar stems were highest at the stem base (0.3 m) and decreased with increasing measurement height. Methane fluxes from ash stems were lowest at the stem base and gradually increased until 3.6 m height. Nitrous oxide fluxes were low and did not show clear spatial patterns. The presence of mosses had no significant effects on CH4 and N2O fluxes. Conclusions: Stem fluxes were small when compared to the corresponding soil fluxes at the non-flooded and infrequently flooded site, but significantly reduced the soil CH4 sink capacity at the frequently-flooded site. Methane flux strongly varied between 0.3 and 3.6 m stem height and showed distinctive tree species specific patterns. Our results therefore suggest that measuring at more than a single location near the stem base is inevitable to obtain any reliable CH4 or N2O flux estimate of a whole tree stem. [ABSTRACT FROM AUTHOR]

Distribution pattern, nest-tree characteristics and reproductive features of Black Stork's population were evaluated in the floodplains of Gornje Podunavlje in Northwestern Serbia over five consecutive years. In total, 44 diff erent nests were discovered and monitored. Nests were mostly placed on wide-diameter European Oaks and White Poplars between 5.5 and 18 m above ground level. Annually, the number of occupied nests varied between 26 and 16 with the declining trend over study years. The mean nesting density was 9.8 ± 2 occupied nests per 100 km². Through study area, occupied nests were uniformly distributed and very isolated concerning the conspecifi c pairs. Predominantly, Black Stork preferred to nest on the lateral branches of the autochthonous mature trees with straight trunks and extensive crowns. These results suggest that the existence of old native forest stands represent crucial microhabitat criteria in the choice of the particular nesting site. In almost half of successful nesting cases, the most frequent number of fledglings was three. Overall productivity was relatively low with some variations between years implying poor nesting success. [ABSTRACT FROM AUTHOR]

Agriculture in Central Asia largely relies on irrigation. The water is withdrawn from the rivers of the region, which predominantly originate from snowfields and glaciers. Due to global warming, these water resources are expected to decline substantially, resulting in an aggravation of already existing water scarcity. Tree shelterbelt systems, as the most prominent practice of agroforestry in Central Asia, are reported to help to reduce water consumption in irrigated agriculture. Populus. alba is one of the most important shelterbelt trees in Central Asia. Though, studies about water consumption of shelterbelts are lacking. Therefore, the objectives of this study are to (1) investigate water consumption of Populus alba trees in a shelterbelt system in Central Asia and (2) analyze the influence of local climatic conditions on the sap flow of such a shelterbelt. Tree water consumption was assessed through sap flow measurements on three trees in a crop shelterbelt system in the Chui Valley in South Eastern Kazakhstan during June and July 2016. The average daily water consumption was 187.6 l/d, 44.8 l/d, and 160 l/d for the trees, respectively. These results were extrapolated for a representative shelterbelt section. Water consumption of that section was 7.8 mm/d, while average ETo was 5.3 mm/d. Considerable influences of water vapor saturation deficit, air temperature and relative humidity on the sap flow could be observed. Solar radiation played a role, too, whereas little or no influence of wind speed on tree water consumption was found.

In response to gravistimulation under anisotropic light, tree stems showing an active cambium produce reaction wood that redirects the axis of the trees. Several studies have described transcriptomic or proteomic models of reaction wood relative to the opposite wood. However, the mechanisms leading to the formation of reaction wood are difficult to decipher because so many environmental factors can induce various signalling pathways leading to this developmental reprogramming. Using an innovative isotropic device where the phototropic response does not interfere with gravistimulation we characterized the early molecular responses occurring in the stem of poplar after gravistimulation in an isotropic environment, and without deformation of the stem. After 30 min tilting at 35° under anisotropic light, we collected the upper and lower xylems from the inclined stems. Controls were collected from vertical stems. We used a microarray approach to identify differentially expressed transcripts. High-throughput real-time PCR allowed a kinetic experiment at 0, 30, 120 and 180 min after tilting at 35°, with candidate genes. We identified 668 differentially expressed transcripts, from which we selected 153 candidates for additional Fluidigm qPCR assessment. Five candidate co-expression gene clusters have been identified after the kinetic monitoring of the expression of candidate genes. Gene ontology analyses indicate that molecular reprogramming of processes such as 'wood cell expansion', 'cell wall reorganization' and 'programmed cell death' occur as early as 30 min after gravistimulation. Of note is that the change in the expression of different genes involves a fine regulation of gibberellin and brassinosteroid pathways as well as flavonoid and phosphoinositide pathways. Our experimental set-up allowed the identification of genes regulated in early gravitropic response without the bias introduced by phototropic and stem bending responses. [ABSTRACT FROM AUTHOR]

Inorganic salts are very important for the biosynthesis of major components such as cellulose and lignin. In order to investigate biomass production, major components of the biosynthesis of plant cell wall and the bioethanol production of Populus alba, we examined the effect of inorganic salts on in vitro culture systems without specific mineral salts. The medium without H2PO4 - was supportive for Populus alba shoot growth, while the absence of NH4 + resulted in poor shoot growth. The medium without H2PO4 - and Fe3+ inhibited aboveground biomass production, whereas NH4 + and K+ deprivation led to an enhancement of the same. The root/shoot ratio of Populus alba in the medium without H2PO4 - was high compared with plants cultured in the control medium. H2PO4 - is deeply involved in lignin biosynthesis, and its removal has been shown to reduce the biosynthesis of lignin. Plants grown on nitrate-free medium were found to be good for enzymatic saccharification and ethanol production. The plants grown in the medium without NO3 - showed 72.0% enzyme digestibility, and the yield of ethanol showed 9.58% ethanol productivity after 12 hours. These results can be used as the basis for producing high-quality biomass for future bioethanol production. [ABSTRACT FROM AUTHOR]

Populus alba is a foundation species in evolutionary and ecological studies in the northern hemisphere. In this study, the chloroplast genome and gene map of P. alba were constructed. The P. alba chloroplast genome is 156,505 bp in length comprising a large single-copy region, two inverted repeat regions and a small single-copy region. The genome contains 131 genes, including 86 protein-coding genes (77 PCG species), eight ribosomal RNA genes (four rRNA species) and 37 transfer RNA genes (30 tRNA species). Phylogenetic analysis indicates that all Populus chloroplast genome sequences are clustered together and divided into three large branches. Among reported Populus chloroplast genomes, the leuce section formed monophyletic, indicating that all Populus spp. have a common maternal ancestor. P. rotundifolia and P. tremula are closely related and are sisters to P. davidiana. P. alba is closely related to P. adenopoda. Population genetic research in ecology and evolution may be easily developed through chloroplast genomes as they are conserved. This research will benefit future studies related to Populus, one of the world's most ecologically and economically important genera. [ABSTRACT FROM AUTHOR]

The study used fractal analysis to evaluate and describe the geometry of the leaves at the Populus alba L. specie. The leaf samples were taken randomly, from mature trees, from the Cenad Forest Protected Area, Timis County, Romania. The leaves were scanned in a 1:1 ratio, and binarized images of the leaves were used for fractal analysis of leaf geometry. The box-counting method was used for the fractal analysis in order to obtain the values of the fractal dimensions (D). Foreground pixels (FP), correlation coefficient R² for D, and standard error (SE) were recorded. The values of the parameters of the leaves L (leaf length), w (leaf width), Per (perimeter), and SLA (scanned leaf area) were determined. The ANOVA test (Alpha = 0.001) confirmed the statistical safety of the data and the presence of variance in the data set (p <0.001, F> Fcrit). The coefficient of variation (CV) indicated the values: CVL = 14.910 for the leaf length parameter (L), CVw = 19.531 for the leaf width parameter (w), CVPer = 16.865 for the leaf perimeter (Per), CVSLA = 33.594 for the scanned leaf area (SLA), CVFP = 33.151 for foreground pixels (FP), and respectively CVD = 2.838 for fractal dimension (D). From the comparative analysis of CV values, it was found that the smallest variation was recorded in the case of fractal dimension (D), and the largest in the case of scanned leaf area (SLA). This suggests that the fractal dimension (D) is the most stable parameter in the characterization of leaf geometry in the species Populus alba L. Diversity profile indicated a similar distribution of the studied parameters. In relation to the dimensional parameters of the leaves, the variation of the fractal dimensions (D) had variable interdependence relations, in conditions of R² = 0.878 in relation to FP, R² = 0.908 in relation to Per, R² = 0.909 in relation to SLA, R² = 0.799 in relation to L and, respectively, R² = 0.698 in relation to w. Polynomial equations, of degree 2, described the variation of the fractal dimensions D in relation to FP, Per and SLA, in statistic safety conditions, p <0.001. [ABSTRACT FROM AUTHOR]

The study aimed to determine the leaf area of poplar by non-destructive methods, based on foliar parameters. The biological material was represented by the Populus alba L. species, from the Protected Area Cenad Forest. Leaves were taken, randomly from the crown of trees, from mature branches. The values of the parameters leaf length (L) and leaf width (w) were obtained by measuring with a ruler, with an accuracy of ± 0.5mm. The leaves were scanned in a 1: 1 ratio. From the imaging analysis of the images, the values of the scanned leaf area (SLA) and the leaf perimeter (Per) were obtained with a high precision. To determine the values of the measured leaf area (MLA), as a nondestructive method, a relation of type MLA = L · w · CF was used, where CF is the correction factor and its value influences the accuracy in finding the MLA values. The ANOVA single factor test confirmed the data safety and the presence of variance in the experimental data set. The value CF = 0.66, at which the minimum value of the mean error (MEM) between SLA and MLA was obtained, was considered as the optimal value of the correction factor (CF). According the optimal CF value, the measured leaf area (MLA) values were determined. A high degree of matching was found between MLA and SLA values, and the relationship was described by a linear equation, statistically safe, according to R2=0.963, p<0.001. The correlation analysis highlighted the existence of very strong correlations between MLA and SLA (r = 0.981); between MLA and foliar parameters L (r = 0.919), w (r = 0.954), Per (r = 0.961); between SLA and Per (r = 0.952); between SLA and w (r = 0.951); between Per and w (r = 0.935). Strong correlations were recorded between SLA and L (r = 0.888) and between Per and L (r = 0.882), and moderate correlation was recorded between L and w (r = 0.771). The regression analysis facilitated the evaluation of the variation between SLA, respectively MLA and studied leaf parameters. From the analysis of the values of the coefficients of the regression functions, it was appreciated that the width of the leaves (w) had a stronger influence in the description of the leaf area, compared to L and Per. [ABSTRACT FROM AUTHOR]

In this study, the potential of planted (Tamarix tetrandra Pall. ex M.Bieb. and Robinia pseudoacacia L.) and spontaneously colonized (Amorpha fruticosa L. and Populus alba L.) woody species for the phytoremediation of potentially toxic trace elements (TEs) such as As, B, Cr, Cu, Mn, Ni, Se, and Zn, from the chronosequence fly ash (FA) deposit lagoons (L1 and L2) at the ‘Nikola Tesla A’ Thermal Power Plant (TENT-A) in Serbia were analyzed. The differences in the pseodototal and bioavailable (DTPA-extractable) concentrations and mobility (AR index) of TEs in FA at the examined lagoons are a result of the time-conditioned influence of weathering (3 and 11 years respectively) and vegetation development on changing the basic physical and chemical properties of FA (texture, pH, EC, CEC, C, N, and bioavailable P and K) and its toxicity. This resulted in differences in the concentration of TEs in the roots and leaves of the examined plants at L1 and L2. All examined species accumulated Cr the most in the root (BAF > 1 and TF < 1), which suggests that they are good stabilizers of this element. Biological indices for As (BAF > 1 and TF < 1) identified T. tetrandra and A. fruticose as good stabilizers of As. P. alba stood out as accumulating the highest levels of B, Ni, and Zn, T. tetrandra the highest levels of Cu, Mn, and Se, and R. pseudoacacia the highest levels of As and B in leaves (BAF > 1; TF > 1), which makes them good extractors of these elements from the FA at TENT-A. However, due to toxic concentrations of As, B, Se, and Zn in their leaves, they are not recommended for the phytoremediation of the investigated lagoons through the process of phytostabilization. Under conditions of elevated total Cu and Ni concentration in FA, the content of these elements in the leaves of A. fruticosa at both lagoons were within the normal range. This, in addition to a good supply of essential Zn, the stabilization of As and Cr in the roots, an increase in BAF, and a decrease in TF for B with a decrease in its mobility in ash over time, singles this invasive species out as the best candidate for the phytostabilization of TEs in FA at the TENT-A ash deposit site.

Natural poplar (Populus nigra, Populus alba) forests of the Ob River were studied on the northern border of south taiga subzone (vicinities of the town of Kolpashevo, Kolpashevo district of Tomsk Region, 58º18′ N, 82º54′ E) on the floodplain segment formed in 1890–1970. They belong to association Anemonidio dichotomi-Populetum nigrae Taran 1993 (Equiseto hyemalis-Populion nigrae Taran 1997, Salicetalia purpureae Moor 1958, Salicetea purpureae Moor 1958) and 2 subassociations: Anemonidio dichotomi-Populetum nigrae typicum Taran 1993 and Anemonidio dichotomi- Populetum nigrae rubetosum saxatilis Taran subass. nov. The poplar forests were examined from young timber stage of black poplar (Populus nigra) to stage of its total extinction. General direction of the poplar forest succession is expressing in a replacement of black poplar stands by birch ones. On sandy soils, black poplar stands are changed by small-sized Scotch pine ones. At the middle stages of the succession, white poplar (Populus alba) plays a significant role, occasionally along with Populus ×canescens. However, white poplar doesn’t form stable stands near the town of Kolpashevo as it grows there at the northern border of its areal in Western Siberia. In studied poplar forests, the average species saturation was 42.4 and 14.4 species per 100 m2 for vascular plants and for mosses respectively. On the whole, 123 species of vascular plants and 34 species of mosses were registered in the poplar forests.

Background: The plants represent an important source of various chemical structures known for their therapeutic activities in folk medicine. Our study aimed to exploit natural bioactive components from well-known medicinal plants "Rosmarinus officinalis and Populus alba". Methods: The study of acute toxicity of essential oils of Rosemary and White poplar was carried out on Wistar rats. Then, the effect of these essential oils was studied in the treatment of experimental models induced by knee osteoarthritis. A radiographic and Histologic analysis was carried out to monitor the efficiency of essential oil. The choice of the model of osteoarthritis turned to unilateral intra-articular injection of a mono-iodo acetic acid. Results: The results revealed that the action of the essential oil showed a significant decrease in the Mankin score compared to the group of untreated rats. Conclusion: The essential oils of R. officinalis, P. alba presented an protective effect against osteoarthritis with difference degrees.

The interest of this work is the discovery of new antimicrobial agents of plant origin to inhibit the formation of microbial biofilms. The present research was conducted to identify and quantify the phenolic compounds extracted from Populus nigra and Populus alba buds harvested in the area of Tizi-Ouzou (Algeria), and to evaluate their antimicrobial and antibiofilm activity. High performance liquid chromatography (HPLC) was performed to identify the phenolic compounds in the ethyl acetate fraction of P. nigra and the methanolic extracts of P. nigra and P. alba. The antimicrobial activity of the crude extracts and the fractions of these two species was tested against 11 microorganisms, using the disk diffusion method, while the antibiofilm effect of certain extracts was carried out in a 96-well microplate and on a biomaterial (catheter). HPLC analysis revealed the presence of 10 bioactive compounds. The main phenolic compounds identified in the three extracts were p-coumaric acid, ellagic acid, and Kaempferol. This study was able to demonstrate that the extracts of P. nigra and P. alba buds have interesting antimicrobial properties, with diameters ranging from 6.6 to 21.3 mm. In addition, extracts of P. nigra exhibited antibiofilm effects greater than 70%. Our results provide evidence for the antimicrobial and antibiofilm potential of bud extracts from both poplar species. Thus, these results will pave the way for further research on these two plants.

Efficient activated carbon was ultrasonically synthesized from the Populus alba tree, and fluoride ions were removed from samples of synthetic and real wastewaters. The effects of various parameters including pH (2–10), time (5–180 min), contaminant concentration (10–100 mg/L), sorbent dose (1–7 g/L), and co-existing ions on the fluoride removal using Populus alba activated carbon (PAAC) were revealed. The physico-chemical characteristics of PAAC were determined using SEM, FTIR, BET, XRD, and EDX mapping. The specific surface area and pore volume of the mesoporous PAAC were obtained as 707.39m2/g and 0.40 m3/g. The study found that the maximum removal efficiency of fluoride (93.37%) occurred under the fluoride concentration of 10 mg/L, PAAC of 4 g/L, pH of 6, and contact time of 100 min. The isotherms and kinetics data could be suitably reflected by the Freundlich and the pseudo-second-order kinetic models, respectively. Langmuir maximum monolayer adsorption capacity of the ultrasonic-assisted PAAC was measured as 77.12mg/g. Sorption of fluoride ions onto PAAC is feasible and an exothermic process. According to the field test, PAAC can significantly remove fluoride and other pollutants like BOD5, COD, Ni, Co, and Pb from glass and shipyard wastewater samples. [ABSTRACT FROM AUTHOR]