Populus Nigra Research Articles

Detection and confirmation of diagnostic microsatellite loci in Populus nigra and Populus deltoides to identify their hybrids (P. × canadensis)

Poplar cultivation has economic, social, ecological, and environmental importance in Turkey. Even though, Populus × canadensis hybrids play an important role for the commercial poplar cultivation with good growth performance and adaptability, hybrid clones introduced the different region of Turkey have started to replace the native stands of Populus nigra gradually. To continue sustainable cultivation of poplar and to conserve the native stands of P. nigra at the same time, genetic identification, and registration of the Populus cultivars from different origins are essential in breeding programs. Genetic identification and characterization of a natural population of P. nigra growing along the Melendiz River, Populus deltoides, and hybrid P. × canadensis trees were performed by 12 microsatellites loci. In addition, 18 P. nigra trees from EUFORGEN core collection were screened as reference samples. P. deltoides specific alleles were detected at four microsatellite loci previously reported as having diagnostic alleles. Several P. nigra trees from natural population and EUFORGEN core collection also included species-specific alleles of P. deltoides. It is concluded that there is an introgression event between the natural population and cultivated hybrids or P. deltoides clones in the surrounding area. Also, some members of the EUFORGEN core collection could have been mixed up or misidentified as P. nigra. The obtained results indicated that the application of the rigorous standards for reliable identification and registration with large sample size is a necessity for future breeding and conservation programs. Also, conservation of the native Populus nigra trees is an important requirement to prevent the genetic pollution of the species' gene pool and reduction of effective population size.

Diet variations of <i>Procambarus clarkii</i> and <i>Macrobrachium nipponense</i> in natural and modified wetlands at West Dongting Lake

栖息地退化和外来物种入侵都是淡水生态系统中的主要威胁因素，因此，量化不同人类活动干扰强度下外来入侵生物和本土生物的食性组成差异，对于明确种间竞争强度，制定适合的管理对策至关重要.本研究应用碳、氮稳定同位素分析技术，比较了长江中下游西洞庭湖湿地受人类活动干扰程度不同的天然湿地和人工改造湿地中的入侵种克氏原螯虾（Procambarus clarkii）与本土种日本沼虾（Macrobrachium nipponense）的食性组成及差异.2017年8月8-18日在西洞庭湖区不同人类干扰强度的栖息地中采集了两种消费者和5种潜在食物来源样品，共计91个.测定碳氮稳定同位素含量后，使用贝叶斯混合模型，估算不同食物来源对消费者的贡献.研究发现：在两种栖息地中克氏原螯虾与日本沼虾食性均有重叠，且在改造湿地中重叠度更大.与克氏原螯虾相比，日本沼虾消费更多的动物性食物.与天然湿地相比，在改造湿地中由于克氏原螯虾数量更多，与本土种竞争食物资源，克氏原螯虾和日本沼虾δ¹³C比值都显著升高，食性组成均发生了变化，植物性食物来源比重增加.由于食性改变，在改造湿地中仅日本沼虾δ¹⁵N比值显著下降，克氏原螯虾在两种栖息地中δ¹⁵N比值无显著变化.本研究证明，随着人类干扰强度增大，受干扰湿地中外来入侵生物对本土生物的影响增大.;Habitat degradation and alien species invasion are the main threats for freshwater ecosystem. Therefore, quantifying the differences of diet composition between alien invasive and native species under different human disturbance intensities is very important for the understanding of the intensity of interspecific competition and determining appropriate management strategies. In this study, stable carbon and nitrogen isotope analysis technique was used to compare the diet composition and variations between the invasive species of Procambarus clarkii and the native species of Macrobrachium nipponense at open water (nature) and black poplar (Populus nigra) plantation (modified) wetlands in the West Dongting Lake. Ninety-one samples of consumers and potential food sources were collected between August 8 and 18, 2017. Bayesian mixture model were used to estimate diet composition of P. clarkii and M. nipponense at the two types of wetland. Result showed that compared with natural wetland, the number of P. clarkii in the modified wetland was larger and the diet overlap between invasive species (P. clarkii) and native species (M. nipponense) was greater in the modified wetland than in the natural wetland. Compared with P. clarkii, the native specie (M. nipponense) consumed more animal food in natural wetland. In the modified wetland, the δ¹³C for both P. clarkii and M. nipponense increased significantly, and their diet contained higher proportion of plant food sources. However, only M. nipponense showed significant changes in δ¹⁵N, while δ¹⁵N of P. clarkii showed no significant changes between the two habitats. This study suggested that with the increase of human disturbance, the impact of alien invasive organisms on local organisms increased.

Effects of Urban Wastewater Application on Growth, Biomass, Nutrition, and Heavy-Metal Accumulation of Populus Nigra L. '62/154', P. Alba L. '20/45', P. Euramericana (Dode) Guinier '92/40', and Salix Excelsa S.G. Gmel Grown in Heavy-Metal Contaminated Soil

Effects of Urban Wastewater Application on Growth, Biomass, Nutrition, and Heavy-Metal Accumulation of Populus Nigra L. '62/154', P. Alba L. '20/45', P. Euramericana (Dode) Guinier '92/40', and Salix Excelsa S.G. Gmel Grown in Heavy-Metal Contaminated Soil

Chemical characterization of black poplar (Populus nigra L.) sawdust hemicelluloses esterified with acyl chlorides

In the present study, hemicelluloses were isolated from black poplar (Populus nigra L.) sawdust, which is generated by the wood industry in large quantities as lignocellulosic waste. The monosaccharide composition of hemicelluloses was determined by gas chromatography. Xylose was the predominant monosaccharide unit, at 81.13%. Isolated hemicelluloses were then esterified with octanoyl, decanoyl, and lauroyl chloride, and the produced derivatives were characterized in terms of percent yield, degree of substitution (DS), solubility, Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Hemicellulose derivatives had DS values ranging from 0.83 to 0.97, and percent yields ranging from 61.54% to 62.31%. FTIR analysis confirmed esterification. TGA indicated that the hemicellulose derivatives offered lower thermal stabilities than native hemicelluloses. Solubility analysis indicated that esterification increased the hydrophobic capacity of hemicelluloses. Generally, the hemicellulose derivatives obtained could be used to make biodegradable and environmentally friendly plastics, resins, films, and coatings for industrial utilization.

Efficient removal of hexavalent chromium through adsorption-reduction-adsorption pathway by iron-clay biochar composite prepared from Populus nigra

An iron-clay biochar composite (PFB) prepared from invasive Populus nigra was employed for Cr(VI) removal. The results suggested that surface coatings of mineral phases could improve the pore structure, redox moieties, and graphene phase of biochar. The adsorption and reduction rates of Cr(VI) at the initial concentration 100 mg·L-1 in aqueous solution by PFB were 100% and 87.18%, respectively, which was 3.1 and 2.1 times higher than the pristine biochar (PB). Based on the model simulation, the Cr(VI) removal by PFB was a mixed adsorption-reduction-adsorption approach including the electrostatic attraction via film and intraparticle diffusion and chemical interactions, in which the adsorption of Cr(III)c was the main control step. A series of characterizations revealed that -C-O functional groups, Fe(II)oct in Fe3O4, Fe(0), and persistent free radicals (PFRs) were the prominent electron donors involved in the Cr(VI) removal. In addition, the PFB with a graphite-like structure could also serve as an electron shuttle to facilitate Cr(VI) adsorption-reduction.

Content of chemical elements in the ash of black poplar (Populus Nigra L.) leaves in the territory of Northern Kazakhstan

Жұмыстың өзектілігі зерттелетін аумақта жоғары өсімдіктің ең көп таралған түрі және қоршаған ортаның биоиндикаторы ретінде қара терек жапырақтары күлінің (Populus nigra L.) элементтік құрамын зерттеу қажеттілігімен байланысты. Солтүстік Қазақстан аумағында өсетін қара терек (Populus nigra L.) жапырақтарының күліндегі химиялық элементтердің құрамы Томск политехникалық университетінің зертханасында инструменталды нейтронды активациялау анализі әдісімен алынған зерттеулер ұсынылған. Жапырақ күлінде 28 химиялық элементтер анықталды: Na, Ca, Sc, Cr, Fe, Co, Zn, As, Br, Rb, Sr, Ag, Sb, Cs, Ba, La, Ce, Nd, Sm, EU, Tb, Yb, Lu, Hf, Ta, Au, Th, U. Зерттелетін аумақтың қара терек (Populus nigra L.) жапырақтары күліндегі химиялық элементтер құрамының статистикалық параметрлері анықталды, бұл оларда қалыпты және логнормалды заң бар екенін көрсетті. Кластерлік талдау нәтижелері бойынша 10 маңызды қауымдастық анықталды. Ақмола және Солтүстік Қазақстан облыстары үшін спецификалық элементтерді анықтау мақсатында геохимиялық қатарлар салынды. Ол келесі элементтер: Cr, U, Sr, Au, Co, Ca, Na, Lu және Zn. Әдеби көздерге нормалауға қатысты келесі элементтер спецификалық болып саналады; Zn, Sr, Ca, Br, As, Ba. Түйін сөздер:химиялық элементтер, биоиндикатор, қара терек жапырақтарының күлі (Populus nigra L.), инструменталды нейтронды активациялау анализі, Солтүстік Қазақстан.

Responce of Physico-chemical Soil Properties to Wastewater Application And Subsequent Effects on Three Woody Species Plants

Water scarcity is a world-wide problem that is predict to increase as a result of increasing population and subsequent increasing the pressure on water sources. This research aimed to reach a feasible outcome for the possibility of blending industrial effluent with high quality water as a method of reducing the increasing demand on fresh water for irrigation. The study was conduct in the college of Agricultural engineering science- Forestry department from June till October of 2019 to examine the effect of blending wastewater of two types of industrial wastewater from different regions with tap water at three dilutions for each (25%, 50%, and 75%) along with the control. Factorial Randomized Complete Block Design (RCBD) was used to analyze the physical and chemical properties of water, soil and growth parameter of three species (Platanus orientalis L., Eucalyptus camaldulensis Dehn, and Populus nigra L.). The results revealed that the soil properties (temperature, pH, electrical conductivity, potassium, nitrate, bicarbonate, sulfate, chloride, and phosphate) were directly affected by water trends since pH of R2 ww. has an acidic nature (5.3) as well the soil irrigated with this wastewater record pH value lower than 6 in all months. The EC of R1 ww. record high values so as the soil irrigated with different dilutions of it which reach 2.5 ds.m-1 when the concentration was 75% which was significantly different from control soil (0.5 ds.m-1). Moreover, increasing the concentration of wastewater lead to form unfavorable soil for the growth of tested plants by recording lower root and shoot biomass when the concentration of wastewaters was > 25% as well as, the chlorophyl content which record an increment in eucalyptus in chlorophyl a, b, and total when irrigated with 25% R1 ww. and R2 ww. then a reduction observed when wastewater concentration increased. Aforementioned finding led to a conclusion that diluting wastewater with tap water increased the survival rate of plants and mitigate the properties of water which can be recommended to be used as a substitution for irrigation

Metal bioaccumulation, translocation and phytoremediation potential of some woody species at mine tailings

This study aimed to determine the concentrations of ten metals (Mn, Ni, Ca, Mg, Fe, Zn, Cr, Pb, Cd, Cu) in the soil at depths of 10 and 20 cm and selected plant species (Populus nigra L., Fraxinus ornus L., Salix alba L., Salix caprea L.), as well as to assess the ability of these plants of metal bioaccumulation, translocation and phytoremediation on the location of the mine pit and flotation tailings of the selected mine (in the center of the Republic of Serbia). The concentrations of Pb and Cu in the investigated soil at a depth of 10 cm were above remediation values stated in the regulations of the Republic of Serbia. At the same time, the concentration of Cd, Cr, Pb and Cu was above the limit values in both of the examined soil depths, while Ni in the soil at a depth of 10 cm was above the limit value determined in the Directives of the European Union. The species F. ornus shows the ability to phytoextract Ca, species P. nigra Zn, Ca and Cd, while both Salix species have the capacity to phytoextract Zn and Ca. The results showed that species S. alba is an efficient bioaccumulator of Mn, Fe, Cr, Pb, Zn and Ca, S. caprea of Fe, Cu, Cr, Mg and Pb, and P. nigra of Mn and Cd. The bioaccumulation and translocation of the investigated elements depend on plant species and their organ. The selection of plant species adequate for remediation should take this into account.

Genome-wide identification and expression analysis of the xyloglucan endotransglucosylase/hydrolase gene family in poplar

BackgroundXyloglucan endotransglucosylase/hydrolase (XTH) family plays an important role in cell wall reconstruction and stress resistance in plants. However, the detailed characteristics of XTH family genes and their expression pattern under salt stress have not been reported in poplar.ResultsIn this study, a total of 43 PtrXTH genes were identified from Populus simonii × Populus nigra, and most of them contain two conserved structures (Glyco_hydro_16 and XET_C domain). The promoters of the PtrXTH genes contain mutiple cis-acting elements related to growth and development and stress responses. Collinearity analysis revealed that the XTH genes from poplar has an evolutionary relationship with other six species, including Eucalyptus robusta, Solanum lycopersicum, Glycine max, Arabidopsis, Zea mays and Oryza sativa. Based on RNA-Seq analysis, the PtrXTH genes have different expression patterns in the roots, stems and leaves, and many of them are highly expressed in the roots. In addition, there are11 differentially expressed PtrXTH genes in the roots, 9 in the stems, and 7 in the leaves under salt stress. In addition, the accuracy of RNA-Seq results was verified by RT-qPCR.ConclusionAll the results indicated that XTH family genes may play an important role in tissue specificity and salt stress response. This study will lay a theoretical foundation for further study on molecular function of XTH genes in poplar.

Latent heat flux variability and response to drought stress of black poplar: A multi-platform multi-sensor remote and proximal sensing approach to relieve the data scarcity bottleneck

High-throughput mapping of latent heat flux (λET) is critical to efforts to optimize water resources management and to accelerate forest tree breeding for improved drought tolerance. Ideally, investigation of the energy response at the tree level may promote tailored irrigation strategies and, thus, maximize crop biomass productivity. However, data availability is limited and planning experimental campaigns in the field can be highly operationally complex. To this end, a multi-platform multi-sensor observational approach is herein developed to dissect the λET signature of a black poplar (Populus nigra) breeding population (“POP6”) at the canopy level. POP6 comprised more than 4600 trees representing 503 replicated genotypes, whose parents were derived from contrasting environmental conditions. Trees were trialed in two adjacent plots where different irrigation treatments (moderate drought [mDr] and well-watered [WW]) were applied. Data collected from satellite and unmanned aerial vehicles (UAVs) remote sensing as well as from ground-based proximal sensors were integrated at consistent spatial aggregation and combined to compute the surface energy balance of the trees through a modified Priestley-Taylor method. Here, we demonstrated that λET response was significantly different between WW and mDr trees, whereby genotypes in mDr conditions exhibited larger standard deviations. Importantly, genotypes classified as drought tolerant based on the stress susceptibility index (SSI) presented λET values significantly higher than the rest of the population. This study confirmed that water limitation in mDr settings led to reduced soil moisture in the tree root zone and, thus, to lower λET. These results pave the way to breeding poplar and other bioenergy crops with this underexploited trait for higher λET. Most notably, the illustrated work demonstrates a multi-platform multi-sensor data fusion approach to tackle the global challenge of monitoring landscape-scale ecosystem processes at fine resolution.

Isolation and Characterization of a Brenneria sp. Shown to Be the Causal Agent of Bleeding Canker Disease of Populus nigra in Iran

Isolation and Characterization of a Brenneria sp. Shown to Be the Causal Agent of Bleeding Canker Disease of Populus nigra in Iran

Effect of Supercritical Extract from Black Poplar and Basket Willow on the Quality of Natural and Probiotic Drinkable Yogurt.

Simple SummaryFermented milk products should be an important component of the human diet due to their high nutritional value and easy digestibility. In order to enhance the nutritional value of yogurts, additives in the form of plant-based raw materials are often used. Phytoextracts are a mixture of biologically active compounds that can have beneficial effects on the human body and influence both the manufacturing process and the quality of food products. The incorporation of extracts from the basket willow (Salix viminalis) into natural and probiotic yogurts reduced the fermentation time and increased their antioxidant activity. Sensory evaluation of the appearance and texture of yogurts enriched with extracts showed no significant differences compared to natural yogurts. The addition of plant extracts may enable the standardisation of yogurt quality and increase its biological activity.Yogurt is a fermented milk drink produced by Streptococcus thermophilus, Lactobacillus delbrüeckii ssp. bulgaricus, or Lactobacillus rhamnosus, which can be enriched with polyphenolic compounds to enhance its antioxidant properties. Supercritical (scCO2/H2O) extracts obtained from the mixture of bark and wood of black poplar (Populus nigra) and basket willow (Salix viminalis) are the source of bioactive compounds. The aim of the study was to assess the effect of supercritical extracts from the P. nigra and S. viminalis on the fermentation, quality, and bioactive properties of drinkable natural and probiotic yogurts. The incorporation of scCO2/H2O extracts at a dose of 0.01% (w/v) into milk for the production of natural and probiotic yogurts increases their functional properties by enhancing the antioxidant activity without causing negative effects on the physicochemical and organoleptic properties of products. The antioxidant activity of yogurt with scCO2/H2O extract from P. nigra and S. viminalis was higher than control yogurts by 1.3–13.2% and 4.4–37.5%, respectively. The addition of a supercritical S. viminalis extract reduced the time of natural and probiotic yogurt fermentation. Natural and probiotic yogurt with scCO2/H2O extracts added was characterised by a bacterial population size of over 7 log cfu/g, and the microflora was active throughout the cold storage period. FTIR analysis confirmed the presence of scCO2/H2O extracts from P. nigra or S. viminalis in both types of yogurt. A secondary structure analysis confirmed interactions between compounds of scCO2/H2O extract from P. nigra and S. viminalis extract with milk proteins. These interactions affect the compounds’ structural and functional properties by changing, e.g., their digestibility and antioxidant properties.

Phosphorus availability and leaching losses in annual and perennial cropping systems in an upper US Midwest landscape

Excessive phosphorus (P) applications to croplands can contribute to eutrophication of surface waters through surface runoff and subsurface (leaching) losses. We analyzed leaching losses of total dissolved P (TDP) from no-till corn, hybrid poplar (Populus nigra X P. maximowiczii), switchgrass (Panicum virgatum), miscanthus (Miscanthus giganteus), native grasses, and restored prairie, all planted in 2008 on former cropland in Michigan, USA. All crops except corn (13 kg P ha−1 year−1) were grown without P fertilization. Biomass was harvested at the end of each growing season except for poplar. Soil water at 1.2 m depth was sampled weekly to biweekly for TDP determination during March–November 2009–2016 using tension lysimeters. Soil test P (0–25 cm depth) was measured every autumn. Soil water TDP concentrations were usually below levels where eutrophication of surface waters is frequently observed (> 0.02 mg L−1) but often higher than in deep groundwater or nearby streams and lakes. Rates of P leaching, estimated from measured concentrations and modeled drainage, did not differ statistically among cropping systems across years; 7-year cropping system means ranged from 0.035 to 0.072 kg P ha−1 year−1 with large interannual variation. Leached P was positively related to STP, which decreased over the 7 years in all systems. These results indicate that both P-fertilized and unfertilized cropping systems may leach legacy P from past cropland management.

Promising introduced Black Cottonwood species for bioenergy and forage production

The winter-hardy introduced North American Populus trichocarpa Torr. & Gray is of particular interest. The results of the study of some clones of poplar on the experimental sites of the Voronezh region are presented. It was found that the rootability of standard stem cuttings of poplar was 98-100%. The survival of plants during the first 3-5 years varied from 75 to 100%. The growing season in different years was 135-146 days. The yield of standard cuttings on root-cutting plantations under favorable conditions and optimal age varied in different clones from 592 000 to 1 380 000 pieces per ha. The wood stock at the age of economical exploitability (~25 years) reached 400 m3/ha, while the stock of local balsam poplar at the same age reached 220 m3/ha. The green mass of leaves contained 0.22-0.28 feed units/kg. In addition, the content of digestible protein, calcium, phosphorus, carotene, crude protein, crude fat, crude fiber, nitrogen-free extractives and ash was determined. In general, studied clones of P. trichocarpa can be used in short rotation coppices for bioenergy and feed production, as well as in reclamation plantings. Clones of the poplar can be used in hybridization with black poplars to increase their winter hardiness.

Effects of pre-hydrolysis applied before kraft-based pulp production on the chemical composition of Black poplar (Populus nigra L.) wood particles

Ön hidroliz, kraft kağıt hamuru üretiminden önce hemiselülozların uzaklaştırılması için odun yongalarının yüksek sıcaklıkta işleme tabi tutulması olarak tanınmaktadır. Bu çalışmada, Karakavak (Populus nigra L.) yongalarına 5, 10, 15, 20, 30 ve 50 dakika boyunca 170 °C'de sıcak su ile ön hidroliz uygulanmış ve ön hidrolizin yongaların kimyasal bileşiminde yarattığı değişimler incelenmiştir. Ön hidroliz, yongaların α-selüloz ve ekstraktif madde içeriklerini artırırken, lignin, holoselüloz ve hemiselüloz içeriklerini azaltmıştır. Hemiselülozların ön hidroliz işleminin ilk dakikalarında hızla azaldığı gözlenmiştir. Hemiselüloz birimlerinden ksiloz, mannoz ve galaktoz miktarlarında ön hidroliz sürecinde belirgin bir düşüş tespit edilmiştir. Arabinoz içeriğinde küçük değişiklikler gerçekleşmiştir. Galaktoz ön hidrolizin on beşinci dakikasında, ramnoz ise ilk dakikalarında yongaları terk etmiştir. 170 °C’de Karakavak yongalarından hemiselülozların %78.43’ünü uzaklaştırması ve α-selüloz oranını %18.71 artırması nedeniyle sıcak su ile en uygun hidroliz süresinin otuz dakika olabileceği görülmüştür.

The Effectiveness of Malaise Traps, H-Traps, and Sticky Traps for Collecting Horseflies (Diptera: Tabanidae)

The Effectiveness of Malaise Traps, H-Traps, and Sticky Traps for Collecting Horseflies (Diptera: Tabanidae)

How to achieve a higher selection plateau in forest tree breeding? Fostering heterozygote×homozygote relationships in optimal contribution selection in the case study of Populus nigra.

In breeding, optimal contribution selection (OCS) is one of the most effective strategies to balance short‐ and long‐term genetic responses, by maximizing genetic gain and minimizing global coancestry. Considering genetic diversity in the selection dynamic—through coancestry—is undoubtedly the reason for the success of OCS, as it avoids preliminary loss of favorable alleles. Originally formulated with the pedigree relationship matrix, global coancestry can nowadays be assessed with one of the possible formulations of the realized genomic relationship matrix. Most formulations were optimized for genomic evaluation, but few for the management of coancestry. We introduce here an alternative formulation specifically developed for genomic OCS (GOCS), intended to better control heterozygous loci, and thus better account for Mendelian sampling. We simulated a multigeneration breeding program with mate allocation and under GOCS for twenty generations, solved with quadratic programming. With the case study of Populus nigra, we have shown that, although the dynamic was mainly determined by the trade‐off between genetic gain and genetic diversity, better formulations of the genomic relationship matrix, especially those fostering individuals carrying multiple heterozygous loci, can lead to better short‐term genetic gain and a higher selection plateau.

Influence of drought and salt stress on the growth of young Populus nigra ‘Italica’ plants and associated mycorrhizal fungi and non-mycorrhizal fungal endophytes

Populus nigra ‘Italica’ (Lombardy poplar) is a breeding cultivar of black poplar, widely used as a street tree or windbreak, often exposed to salinity and limited water availability. Populus roots can develop dual mycorrhizal associations with ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) fungi, and with non-mycorrhizal fungal endophytes (FE). The symbiotic fungi may alleviate the effects of adverse environmental conditions. We investigated the performance (growth and symbiotic associations) of one-year-old Populus nigra ‘Italica’ grown from woody cuttings in soil from natural poplar habitat and subjected to water scarcity and soil salinity (50 mM NaCl, 150 mM NaCl, 250 mM NaCl). With increasing soil salinity, a decrease in the growth parameters of the aboveground parts of the poplar plantlets and their fine roots were found; however, the roots were more resistant to the stress factors analyzed than the shoots. ECMF, AMF, and non-mycorrhizal FE were all tolerant to increased salt levels in the soil, and the ECM abundance was significantly higher under conditions of mild salinity (50 mM NaCl, 150 mM NaCl) compared to the control plants and those treated with 250 mM NaCl. Our results indicated that enhanced soil salinity increased the content of sodium and chlorine in leaves, but did not affect significantly the concentrations potassium, magnesium, calcium, phosphorus, or nitrogen. Significant accumulation of proline in leaves suggest salt stress of P. nigra ‘Italica’ treated with 250 mM NaCl and contribution of proline to the plant defense reactions.

DECAY RESISTANCE, DIMENSIONAL STABILITY AND MECHANICAL STRENGTH OF POPLAR WOOD MODIFIED WITH PLANT-DERIVED COMPOUNDS

The cinnamaldehyde, salicylic acid, stearolic acid and citric acid were plant-derived organic compounds that can be activated to fungi, that could degrade the wood in long term. The compounds with concentrations of 3%, 5% and 7% assisted by different dispersants were impregnated into poplar (Populus nigra L.) specimens by the vacuum-pressure method. After that, weight percentage gain (WPG), decay resistance against white-rot fungi (Trametes versicolor) and brown-rot fungi (Gloeophyllum trabeum), color change, dimensional stability and mechanical properties including modulus of elasticity (MOE) and modulus of rupture (MOR) were measured. The results indicated that cinnamaldehyde impregnated poplar showed antifungi activity against both G. trabeumand T. versicolor, and citric acid impregnated poplar showed antifungi activity against G. trabeum. The color of poplar specimens before and after impregnated cinnamaldehyde and citric acid had a little change, dimensional stability had been improved and mechanical properties especially for MOR increased significantly.

Genetic Regulation of Vessel Morphology in Populus.

During secondary growth, forest trees can modify the anatomy of the wood produced by the vascular cambium in response to environmental conditions. Notably, the trees of the model angiosperm genus, Populus, reduce the risk of cavitation and hydraulic failure under water stress by producing water-conducting vessel elements with narrow lumens, which are more numerous and more interconnected with each other. Here, we determined the genetic architecture of vessel traits affecting hydraulic physiology and resilience to water stress. Vessel traits were measured for clonally replicated genotypes of a unique Populus deltoides x nigra population carrying genomically defined insertions and deletions that create gene dosage variation. We found significant phenotypic variation for all traits measured (mean vessel diameter, height-corrected mean vessel diameter, vessel frequency, height-corrected vessel frequency, vessel grouping index, and mean vessel circularity), and that all traits were under genetic control and showed moderate heritability values, ranging from 0.32 to 0.53. Whole-genome scans of correlations between gene dosage and phenotypic traits identified quantitative trait loci for tree height, mean vessel diameter, height-corrected mean vessel diameter, height-corrected vessel frequency, and vessel grouping index. Our results demonstrate that vessel traits affecting hydraulic physiology are under genetic control, and both pleiotropic and trait-specific quantitative trait loci are found for these traits.