Populus Nigra Research Articles

Changes in abscisic acid content during and after drought are related to carbohydrate mobilization and hydraulic recovery in poplar stems.

Drought compromises plant's ability to replace transpired water vapor with water absorbed from the soil, leading to extensive xylem dysfunction and causing plant desiccation and death. Short-term plant responses to drought rely on stomatal closure, and on the plant's ability to recover hydraulic functioning after drought relief. We hypothesize a key role for abscisic acid (ABA) not only in the control of stomatal aperture, but also in hydraulic recovery. Young plants of Populus nigra L. were used to investigate possible relationships among ABA, non-structural carbohydrates (NSC) and xylem hydraulic function under drought and after re-watering. In Populus nigra L. plants subjected to drought, water transport efficiency and hydraulic recovery after re-watering were monitored by measuring the percentage loss of hydraulic conductivity (PLC) and stem specific hydraulic conductivity (Kstem). In the same plants ABA and NSC were quantified in wood and bark. Drought severely reduced stomatal conductance (gL) and markedly increased the PLC. Leaf and stem water potential, and stem hydraulic efficiency fully recovered within 24h after re-watering, but gL values remained low. After re-watering, we found significant correlations between changes in ABA content and hexoses concentration both in wood and bark. Our findings suggest a role for ABA in the regulation of stem carbohydrate metabolism and starch mobilization upon drought relief, possibly promoting the restoration of xylem transport capacity.

Phytochemical screening and allelopathic evaluation of aqueous and methanolic leaf extracts of Populus nigra L.

Phytochemical screening and allelopathic evaluation of aqueous and methanolic leaf extracts of Populus nigra L.

Adaptability of Tree Species as Windbreaks for Urban Farms in the U.S. Intermountain West

Windbreaks or shelterbelts are a management tool to protect crops from damaging horizontal wind flow, and may provide a useful buffer between farmland and urbanized areas by reducing pesticide drift, dust, and noise associated with farming activities. Plant selection for windbreaks in the Intermountain West can be difficult as high elevation coupled with extreme temperatures, high pH soils, and limited access to water are common. This study assessed eight tree species for suitability as a windbreak in the Intermountain West, with a particular focus on initial establishment and use at the urban–agriculture interface. Species were assessed for mortality, size, canopy density, insect and disease issues, and initial cost. Measurements of shadow characteristics were used as a novel approach to compare canopy density and porosity. Standard poplar (Populus x canadensis) and ‘Theves’ columnar poplar (Populus nigra ‘Afghanica’) were the most effective at rapid establishment, but species with more moderate growth rates, such as aspen, juniper, and hackberry, may provide lower long-term maintenance costs for the environmental conditions found in the Intermountain West.

COMPARATIVE STUDY OF FLAVONOID COMPOSITION OF LEAVES OF PHARMACOPEIAL SPECIES OF THE GENUS POPULUS

The comparative study of the flavonoid composition of leaves of black poplar (Populus nigra L.), balsamic poplar (Populus balsamifera L.), canadian poplar (Populus deltoides Marsh.) and laurel poplar (Populus laurifolia Ledeb.) was held to determine the most perspective species as source of biologically active compounds. Nowadays poplar buds are registered as pharmacopeial medicinal raw material with antimicrobial, antifungal, anti-inflammatory and wound healing effects. It is also known that poplar leaves are used in folk medicine as an analgesic, antibacterial and anti-inflammatory agent. The leaves are also considered to be a perspective medicinal plant raw material along with buds. As a result of the comparative chromatographic analysis using detection at a wavelength of 366 nm and an alcoholic solution of aluminum chloride (AlCl3), rutin was found in all investigated extracts from the leaves of pharmacopeial species of poplars. Moreover, in extracts from Populus balsamifera L. and Populus laurifolia Ledeb. was revealed the presence of pinostrobin. It was determined that in all UV spectra of extracts from the leaves of the investigated poplar species, a long-wave batochromic shift were observed in the presence of 3% alcohol solution AlCl3, which indicates the presence of flavonoids. In the conditions of differential spectrophotometry, the maximum absorption in the range of 406–412 nm was observed, which indicates the necessity of using rutin standard which have maximum absorption at a wavelength of 414±2 nm. The content of the total flavonoids at the wavelength of 414 nm calculated on rutin in all samples was determined, which varies from 2.04% to 4.61% and corresponds to the recommended lower limit of the content of the total flavonoids (not less than 2.0%).

The Occurrence of Sulfated Salicinoids in Poplar and Their Formation by Sulfotransferase1.

Salicinoids form a specific class of phenolic glycosides characteristic of the Salicaceae. Although salicinoids accumulate in large amounts and have been shown to be involved in plant defense, their biosynthesis is unclear. We identified two sulfated salicinoids, salicin-7-sulfate and salirepin-7-sulfate, in black cottonwood (Populus trichocarpa). Both compounds accumulated in high amounts in above-ground tissues including leaves, petioles, and stems, but were also found at lower concentrations in roots. A survey of salicin-7-sulfate and salirepin-7-sulfate in a subset of poplar (Populus sp.) and willow (Salix sp.) species revealed a broader distribution within the Salicaceae. To elucidate the formation of these compounds, we studied the sulfotransferase (SOT) gene family in P trichocarpa (PtSOT). One of the identified genes, PtSOT1, was shown to encode an enzyme able to convert salicin and salirepin into salicin-7-sulfate and salirepin-7-sulfate, respectively. The expression of PtSOT1 in different organs of P trichocarpa matched the accumulation of sulfated salicinoids in planta. Moreover, RNA interference-mediated knockdown of SOT1 in gray poplar (Populus × canescens) resulted in decreased levels of sulfated salicinoids in comparison to wild-type plants, indicating that SOT1 is responsible for their formation in planta. The presence of a nonfunctional SOT1 allele in black poplar (Populus nigra) was shown to correlate with the absence of salicin-7-sulfate and salirepin-7-sulfate in this species. Food choice experiments with leaves from wild-type and SOT1 knockdown trees suggest that sulfated salicinoids do not affect the feeding preference of the generalist caterpillar Lymantria dispar A potential role of the sulfated salicinoids in sulfur storage and homeostasis is discussed.

Poplar Biochar as an Alternative Substrate for Curly Endive Cultivated in a Soilless System

Imminent necessity for eco-friendly and low-cost substitutes to peat is a defiance in the soilless plant cultivation systems. Wood biochar could entirely or partly substitute peat as a plant growing constituent to produce vegetables. Nevertheless, knowledge concerning potential plant performance of leafy green vegetables grown on wood biochar is restricted. The present study assessed the main physicochemical traits of various growing media constituted by decreasing the content of peat and by increasing the percentages of poplar wood biochar. Yield, nutritional and functional properties of curly endive plants cultivated in a protected environment were also tested. Biochar was pyrolyzed from poplar (Populus nigra L.) at 450 or 700 °C for 48 h. Increasing biochar concentration and pyrolysis temperature resulted in higher pH, EC and K content of the growing mediums. Biochar was also effective in increasing particle density and bulk density. Biochar at 70% and pyrolysis temperature of 450 °C significantly increased head fresh weight by 47.4%, head height by 24.9%, stem diameter by 21.5% and number of leaves by 80.8%, respectively compared with the control (100% peat). Head dry matter content, root dry matter content, SSC, ascorbic acid and total phenolic were also significantly affected by this treatment. Furthermore, the addition of biochar and the use of higher pyrolysis temperature decreased N leaves concentration. This represents a particularly important target for leafy green vegetables healthiness.

A Leaf Selfie: Using a Smartphone to Quantify Leaf Vulnerability to Hydraulic Dysfunction.

Accurate predictions of species distribution under current and future climate conditions require modeling efforts based on clear mechanistic relationships between climate variables and plant physiological functions. Vulnerability of leaves to xylem embolism is a key mechanistic trait that might be included in these modeling efforts. Here, we propose a simple set-up to measure leaf vulnerability to embolism on the basis of the optical method using a smartphone, a light source, and a notebook. Our data show that this proposed set-up can adequately quantify the vulnerability to xylem embolism of leaf major veins in Populus nigra and Ostrya carpinifolia, producing values consistent with those obtained in temperate tree species with other methods, allowing virtually any laboratory to quantify species-specific drought tolerance on the basis of a sound mechanistic trait.

In Vitro and In Vivo Effect of Poplar Bud Extracts on Phytophthora infestans: A New Effective Biological Method in Potato Late Blight Control.

The effect of populin extract from black poplar (Populus nigra) on seven different late blight strains was tested under laboratory and field conditions. The growth rate of hyphae was found to be significantly lower in vitro after 3 and 4 v/v% populin applications. Stain M16 was resistant to populin treatment under lab conditions, however. Both 5% and 10% concentration populin reduced the M16 strain’s severity on potato leaves under field conditions and proved to be even more effective than conventionally used fungicides Infinito 687 Sc and Valis M. Higher infection intensity at the 1% level was observed after 24 h using Valis M, and the same trend toward 10% infection remained after 48 and 72 h as well. Low, almost-no-infection intensity was detected after populin 5% and 10% treatment under an open field condition. Altogether, it can be concluded that populin extract can be a low-cost option for growers and an environmentally friendly approach in late blight control.

Poplar PdPTP1 Gene Negatively Regulates Salt Tolerance by Affecting Ion and ROS Homeostasis in Populus

High concentrations of Na+ in saline soil impair plant growth and agricultural production. Protein tyrosine phosphorylation is crucial in many cellular regulatory mechanisms. However, regulatory mechanisms of plant protein tyrosine phosphatases (PTPs) in controlling responses to abiotic stress remain limited. We report here the identification of a Tyrosine (Tyr)-specific phosphatase, PdPTP1, from NE19 (Populus nigra × (P. deltoides × P. nigra). Transcript levels of PdPTP1 were upregulated significantly by NaCl treatment and oxidative stress. PdPTP1 was found both in the nucleus and cytoplasm. Under NaCl treatment, transgenic plants overexpressing PdPTP1 (OxPdPTP1) accumulated more Na+ and less K+. In addition, OxPdPTP1 poplars accumulated more H2O2 and O2·−, which is consistent with the downregulation of enzymatic ROS-scavengers activity. Furthermore, PdPTP1 interacted with PdMAPK3/6 in vivo and in vitro. In conclusion, our findings demonstrate that PdPTP1 functions as a negative regulator of salt tolerance via a mechanism of affecting Na+/K+ and ROS homeostasis.

Plant detritus origin and microbial–detritivore interactions affect leaf litter breakdown in a Central Apennine (Italy) cold spring

The decomposition of dead organic matter is a key process for the metabolism and functioning of lotic ecosystems. Particulate organic matter from fallen leaves is the main source of energy input also in forested springs. However, detritus processing in spring habitats has been rarely investigated. The present paper is aimed to assess, for the first time, the influence of detritus origin on leaf litter breakdown in a hydrologically, thermally and chemically stable cold spring and to evaluate the relative contribution of microorganisms and invertebrate detritivores to the decomposition process. For this purpose, we used leaves of the native black poplar (Populus nigra) and the invasive common reed (Phragmites australis) enclosed in leaf-bags of different mesh sizes. We demonstrated that leaf detritus of native black poplar decomposed twofold faster than the invasive common reed. We also found that the percentage of dry mass loss was significantly higher in medium/coarse litter bags compared to fine ones. However, microorganisms alone in fine mesh bags were able to decompose about 80% (poplar) and 60% (common reed) of the initial dry mass. No substantial differences were detected in structure, composition and functional organization of assemblages colonizing poplar and common reed leaf-bags. Therefore, differences in microbial activity and microbial/detritivore interactions rather than composition, diversity and abundance of the detritivore guild could better explain the faster breakdown of native leaves. Our results suggest that the substitution of natural riparian vegetation with invasive low-quality leaf plant species will have severe impacts on spring ecosystems. Alterations of structural and functional attributes of springs will be strictly related to the specific characteristics of plant invaders and to local conditions which may influence the detritivore/microbial contribution to leaf litter decomposition/breakdown.

Age dynamics of growth and development of Populus Pyramidalis in city planting

ABSTRACT Plantations of Populus nigra L. x Populus nigra f. Italica Duroi, growing on the territory of the Ufa industrial hub of the Republic of Bashkortostan Forest-steppe region of the European part of Russia, were selected as an object of study. It is proved that the poplar hybrid is a fast-growing tree. The average growth in height is 0.95 m, in diameter 0.85 mm. The growth of side shoots on average is 50–55 cm during the growing season. The annual linear growth of lateral shoots of the first order of poplar is closely correlated with the sum of the effective temperatures. The hybrid in all urban plantings showed high decorative qualities. With age, the decorativeness of the trees is slightly reduced. The high scores of sanitary, living condition, aesthetic assessment of trees are observed in stands of II, III, IV, V, VI classes of age (up to 30 years). The change in the values of the measured indicators in these age frames is statistically unreliable.

When scientists become detectives: investigating systematic tree poisoning in a protected cove

The systematic killing of trees is usually aimed at eradicating pests or alien plant species susceptible to harm existing natural ecosystems. In some cases, trees may become the subject of dispute between neighbors, which sometimes ends in tree death after months or years of dispute. In this paper, we analyze a case of clandestine tree killing and look into ways through which evidence left by delinquents can be analyzed a posteriori with state-of-the-art approaches. The investigation presented here looks at a series of old-growth trees that were supposedly poisoned inside a protected, nineteenth century grove in Switzerland. After the sudden, unexplained death of several old Black poplar (Populus nigra) trees along the main alley in fall 2015 and their subsequent removal, the dying of five additional, neighboring Sycamore maple (Acer pseudoplatanus) and English walnut (Juglans regia) trees in 2016 promptly triggered a suite of criminal investigations at the property. During an initial inspection, a large number of boreholes was found in the root plates of the dying trees. We present findings obtained from tree-ring, wood anatomical and dendrogeochemical investigations performed on root, stem and leave material from the assumedly poisoned trees and show that massive amounts of chemical elements – supposedly in the form organic pesticides with high Al, As, Fe, Cr, Ni contents, aluminum phosphides or glyphosate-based pesticides – were injected into 36 boreholes drilled into the roots around September 2016. Results obtained in this study are currently used in criminal investigations, and are a nice example of how scientific detectives can help their “real World” colleagues in identifying delinquents.

The effect of liming and nitrogen application on common osier and black poplar biomass productivity and determination of biofuel quality indicators

Experiments with two short rotation woody energy crops, common osier (Salix viminalis L.) and black poplar (Populus nigra L.) were carried out in Western Lithuania (55°43′ N, 21°27′ E) on a naturally acid moraine loamy Retisol. According to the results averaged over the two successive growing rotations (2008–2012 and 2013–2016), the dry matter (DM) yield of common osier amounted to 74.76 t ha−1 and 71.63 t ha−1, respectively and that of black poplar totalled 42.28 and 54.24 t ha−1. Nitrogen fertilization significantly increased the number of stems and DM yield for both crops, while stem height was increased only for osier. High-quality chaff of common osier and black poplar was produced using a screw chopper. Our study evidenced that common osier and black poplar biomass feedstock meets the requirements for high quality solid biofuel. When chopped by a screw chopper, wet chaff (40–55% moisture content) may be burned in high and medium power boilers equipped with combustion devices suitable for the incineration of wet chopped woody plants.

Bioassay-Guided Isolation of Nigracin, Responsible for the Tissue Repair Properties of Drypetes Klainei Stem Bark

Drypetes klainei Pierre ex Pax is used in Cameroon by Baka people in the wound healing process and for the treatment of burns. In a previous paper we demonstrated the ability of both water (WE) and defatted methanol (DME) extracts to accelerate scratch wound closure in fibroblast cultures, thus validating the traditional use of D. klainey stem bark in the treatment of skin lesions. In this work we carried out a bioassay-guided fractionation of the most active DME, which exhibited in vitro efficacy in accelerating wound healing process, in order to isolate and identify the compound/s responsible for the assessed biological activity. HPLC was used for the metabolite profiling of DME and fractions (analytical) and for the isolation of the bioactive compound (semi-preparative). MS analyses and NMR spectroscopy were used for identifying the isolated compound. The abilities of treatments in accelerating wound healing were studied on murine fibroblasts in terms of cell viability and cell migration (scratch wound-healing assay). The results obtained allowed to unambiguously identify the isolated bioactive compound as nigracin, a known phenolic glycoside firstly isolated and characterized from bark and leaves of Populus nigra in 1967. However, this is the first time that nigracin is identified in the Drypetes genus and that a wound healing activity is demonstrated for this molecule. Specifically, we demonstrated that nigracin significantly stimulates fibroblast growth and improves cell motility and wound closure of fibroblast monolayer in a dose-dependent manner, without any toxicity at the concentrations tested, and is still active at very low doses. This makes the molecule particularly attractive as a possible candidate for developing new therapeutic options for wound care.

Effectiveness of Different Analytical Methods for the Characterization of Propolis: A Case of Study in Northern Italy.

Propolis is used as folk medicine due to its spectrum of alleged biological and pharmaceutical properties and it is a complex matrix not still totally characterized. Two batches of propolis coming from two different environments (plains of Po Valley and the hilly Ligurian–Piedmont Apennines) of Northern Italy were characterized using different analytical methods: Spectrophotometric analysis of phenols, flavones and flavonols, and DPPH radical scavenging activity, HPLC, NMR, HSPME and GC–MS and HPLC–MS Orbitrap. Balsam and moisture content were also considered. No statistical differences were found at the spectrophotometric analysis; balsam content did not vary significantly. The most interesting findings were in the VOCs composition, with the Po Valley samples containing compounds of the resins from leaf buds of Populus nigra L. The hills (Appennines) samples were indeed characterize by the presence of phenolic glycerides already found in mountain environments. HPLC–Q-Exactive-Orbitrap®–MS analysis is crucial in appropriate recognition of evaluate number of metabolites, but also NMR itself could give more detailed information especially when isomeric compounds should be identified. It is necessary a standardized evaluation to protect and valorize this production and more research on propolis characterization using different analytical techniques.

Evaluation of Salix alba, Juglans regia and Populus nigra as biomonitors of PTEs in the riparian soils of the Sava River.

A large number of human activities result in the release of potentially toxic elements (PTEs) into the environment, which could lead to the degradation of riparian areas. This study aimed to evaluate the potential of Salix alba, Juglans regia and Populus nigra for the biomonitoring of PTEs in the riparian soils of the Sava River. Levels of seven PTEs (As, Cd, Cr, Cu, Ni, Pb and Zn) were measured in the soils, roots and leaves of plants at selected sampling sites and evaluated according to bioaccumulation and translocation factors. The obtained results showed that in riparian soils, As, Cr, Cu, Ni and Zn were at levels considered to be critical for plants. The levels of As, Cd, Cr, Ni and Zn measured in roots of Salix alba and As, Cr, Ni and Zn in its leaves were toxic for plant tissue. Toxic levels of Cr were also measured in the roots of Juglans regia and As in its leaves, as well as As and Cr in the roots of Populus nigra, and Zn in its leaves. Bioconcentration and translocation factors showed that S. alba and P. nigra have potential for the phytoextraction of Zn and Cd, while J. regia has potential for the phytoextraction of As. In terms of phytostabilization potential, S. alba proved to be good for the phytostabilization of Cd and Cu, and J. regia for the phytostabilization of Cr, As, Ni and Pb, while P. nigra showed potential for the phytostabilization of Cr, Ni, Pb and Cu.

Impacts of a partial rainfall exclusion in the field on growth and transpiration: consequences for leaf-level and whole-plant water-use efficiency compared to controlled conditions

• Water use efficiency (WUE), oftentimes estimated as transpiration efficiency (TE): the amount of biomass produced with regard to the water used, has not yet been used as a breeding trait to select poplar genotypes with simultaneously high productivity and conservation of water. Before its application as a selection target, evidence must be presented showing that WUE or its estimators remain constant with age and across environmental conditions.• We conducted a rainfall exclusion experiment in the field on two Populus euramericana (Moench.) and two Populus nigra (L.) genotypes, and assessed leaf-level (A/gs) and whole-plant WUE (DMT/WU as well as their components and related traits. Then, we aimed to compare these results with the same poplar genotypes grown in a glasshouse under contrasting water availability.• Despite a reduction of soil water content and whole-plant transpiration, growth was stimulated in the rainfall exclusion plot, likely as a result of an increased nitrogen assimilation. However, TE values between the glasshouse and the field were similar, and genotype ranking remained fairly constant for transpiration, carbon isotopic discrimination (∆, as a proxy for Wi) and TE. Moreover, even though the drivers of WUE in both experiments were different, increases of WUE measured as ∆ or TE was not associated with lower biomass production. Relatively good agreement was found between ∆ and TE in the field, absence of a similar correlation in the glasshouse is discussed.• These results suggest that ∆ may be a good proxy for TE, and could be used, both as a breeding target for genotype selection in glasshouses without impacting biomass production when planted in the field. However, reduced water availability modified the genotype ranking more significantly than between the field/glasshouse experiments, suggesting a diversity of poplar response to drought that should be considered in breeding strategies.

The GenTree Dendroecological Collection, tree-ring and wood density data from seven tree species across Europe

The dataset presented here was collected by the GenTree project (EU-Horizon 2020), which aims to improve the use of forest genetic resources across Europe by better understanding how trees adapt to their local environment. This dataset of individual tree-core characteristics including ring-width series and whole-core wood density was collected for seven ecologically and economically important European tree species: silver birch (Betula pendula), European beech (Fagus sylvatica), Norway spruce (Picea abies), European black poplar (Populus nigra), maritime pine (Pinus pinaster), Scots pine (Pinus sylvestris), and sessile oak (Quercus petraea). Tree-ring width measurements were obtained from 3600 trees in 142 populations and whole-core wood density was measured for 3098 trees in 125 populations. This dataset covers most of the geographical and climatic range occupied by the selected species. The potential use of it will be highly valuable for assessing ecological and evolutionary responses to environmental conditions as well as for model development and parameterization, to predict adaptability under climate change scenarios.

First report of bleeding canker caused by Rahnella sp. on Populus nigra in Iran

In 2019, a bleeding canker with a sour-smelling and brownish liquid exudate was observed on mature (>10 years old) black poplar (Populus nigra) trees in eight poplar plantations in the Hamadan, Kermanshah, Isfahan, and Kohgiluyeh and…

Peculiarities of development of the black poplar (pópulus nígra) in different forestry conditions, Middle Volga, Russia

The regularities of growth and development of black poplar in various plantings and forest growing conditions are revealed. It is established that the highest tree stands of black poplar are on average 30 m. With a trunk diameter of 44 cm, a class I bonitet, a fullness of the studied rock in a stands of 0, 5 and a stock of wood per 1 ha of 206 m3 are formed in the nettle. The black poplars that grow in the oak forests of the trees have the lowest productivity. The height of the trees and the diameter of the trunks in these forest conditions are on average 42, 1−57, 0 % and 1, 6—1, 8 times less, respectively, than the stands formed in the nettle and the pine-shrub pine forests, as well as by 31, 5 and 33, 3 % of the trees growing in vegetation near the riverside. The black poplar quality class in this type of forest is IV, and the stock of raw wood per 1 ha was only 54 m3, with the standing tree of the studied species of 0, 4.