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Cadmium (Cd) contamination in soil has become a serious worldwide environmental and health problem. Cd is easily taken up by plants and translocated to aboveground tissues. A pot experiment was carried out to explore the role of the ascorbate–glutathione (AsA–GSH) cycle and endogenous hormones in enhancing Cd tolerance and promoting translocation of Cd in one-year-old seedlings of Populus × euramericana ‘Neva’. The antioxidant substances ascorbic acid (AsA), dehydroascorbic acid (DHA), glutathione (GSH), and oxidized glutathione (GSSG); the activities of the antioxidant enzymes ascorbic acid peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), and dehydroascorbic acid reductase (DHAR); the levels of the endogenous hormones indole-3-acetic acid (IAA), abscisic acid (ABA), gibberellin (GA3), and zeatin riboside (ZR); and the contents of malondialdehyde (MDA) and hydrogen peroxide (H2O2) were investigated after 30 days of irrigation with half-Hoagland solution containing 0 or 100 μmol·L–1 Cd(NO3)2 under magnetic treatment (MT) or nonmagnetic treatment (NMT). The results were as follows. (i) Compared with NMT, MT increased the AsA levels in roots compared with those in leaves under Cd stress, whereas it increased the DHA levels in the leaves but decreased the DHA levels in the roots. The GSH and GSSG levels both increased by 8%–151% under MT. (ii) MT inhibited the APX activity in blades and roots, and a similar effect was observed on the foliar activities of GR and MDHAR, with a decrease of 8%–50%; however, MT increased the activation of DHAR in the blades and GR in the roots. In addition, compared with NMT, MT increased the activities of GR, MDHAR, and DHAR by 19%–285% in Populus (poplar). (iii) With the exogenous addition of Cd, the Cd accumulation and biological transport coefficient of Cd from roots to leaves (S/R) were enhanced in poplar, accompanied by increased levels of H2O2 and MDA due to MT. (iv) The levels of IAA, ABA, GA, and ZR were inhibited by 19%–95% in the leaves following MT. In contrast, the levels of these endogenous hormones were increased by 18%–203% in the roots following MT. (v) MT improved the seedling growth of poplar, with an increase of 0.4%–90%, compared with that of the NMT. The ground diameter and number of root tips showed the greatest increases, with average ratios of 29% and 87%, respectively. These results suggested a large increase in AsA and decreases in poplar antioxidant enzymes, especially in the leaves, with a high GSH level. In this review, we concluded that the antioxidant substance GSH plays an important role in the AsA–GSH cycle following exposure to a magnetic field under Cd stress. Additionally, the roots play a major role in eliminating oxygen free radicals by regulating the levels and ratios of various endogenous hormones. Moreover, magnetization could alleviate Cd-induced oxidative stress by stimulating MDHAR, DHAR, and GR activities; enhance the defense capability of the AsA–GSH cycle; and maintain normal physiological metabolism in poplar.

A harsh environment, slow tree growth, nutrient deficiencies, and competition between trees and weeds can impede forest establishment on reclaimed lands. We investigated the effects of torrefied wood chips (TWC) and vermicompost (VC) soil amendments on the growth of Populus euramericana Guinier, weed biomass, and soil chemical properties on reclaimed land in Saemangeum. The 2.5 Mg ha−1 and 5.0 Mg ha−1 TWC had a similar effect on tree diameter and height growth (i.e., 2.5 = 5.0 > 0 TWC) and tended to have similar, higher effect on the total biomass of P. euramericana than the 0 Mg ha−1. The 2.5 Mg ha−1 TWC resulted in a significantly larger root biomass than the 5.0 Mg ha−1 TWC. The weed biomass was significantly larger at the 2.7 Mg ha−1 VC (i.e., 730.5–810.5 g m−2) than the control (605.1–610.6 g m−2), but VC alone was not effective for tree growth and soil amelioration. The TWC had no effect on weed biomass. Thus, the TWC and VC had contrasting effects on tree growth and weed biomass when they were used as soil amendments on salt-affected reclaimed land. VC application may promote weed proliferation, whereas TWC application may potentially increase the growth of P. euramericana and control weed growth on reclaimed lands. Our results enhance the existing knowledge on tree and weed responses to torrefied wood chips and vermicompost amendments for the sustainable management of salt-affected reclaimed lands.

Background In reclaimed land, the growth environment for plants may be unfavorable and the initial establishment and growth of seedlings could be limited because of low nutrient and water availability. Fertilization and control of understory vegetation that competes with seedlings may be of help in ameliorating soil physical and chemical properties, resulting in better seedling growth and reclamation success. However, the amount of nutrients understory vegetation absorbs in this ecological process has been rarely studied. Thus, we aimed to investigate the effect of soil amendment on biomass production and nutrient uptake by weeds in the nutrient-poor reclaimed area. We applied three levels of torrefied wood chip (TWC; 0, 2.5, and 5 Mg ha−1) and two levels of vermicompost (VC; 0 and 2.7 Mg ha−1) as soil physical improvements and organic soil amendments in reclaimed land in the Republic of Korea, with Populus euramericana used as the crop tree. Results TWC did not influence weed biomass, but 2.7 Mg ha−1 VC significantly increased weed biomass by 21% compared to 0 Mg ha−1 VC treatments. Nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na) concentrations in weeds were the highest in control, but there was no statistical difference among treatments. However, VC treatment did marginally increase nutrient uptake in weeds, especially P, K, Ca, and Na. No treatments influenced crop tree height. Conclusion We conclude that VC can be used as an organic source of nutrients in reclaimed soil and that weed management is necessary to increase treatment effects on crop trees in this salt-affected reclaimed land.

Fine roots play important roles in the allocation of forest net primary productivity. Here, to provide insights into the intrinsic and extrinsic factors affecting the root growth, we examined the morphology and longevity of different-order fine roots in two poplar (Populus × euramericana (Dode) Guinier) plantations with contrasting forest productivities. The results indicated that the biomass of fine roots decreased significantly as the root orders increased (P < 0.05). In the plantation with relatively high productivity, the specific root length of the first- and second-order roots was significantly greater than that of the third- to fifth-order roots (P < 0.05). Observations of minirhizotrons showed that roots of the third-order and higher lived longer than the first- and second-order roots. Compared with those in the plantation with relatively low productivity, the cumulative survival rate of the first-order roots was significantly higher in the plantation with relatively high productivity, while that of the third-order or higher roots was lower. The life-span of the first-order roots correlated negatively with soil available inorganic nitrogen, while that of the second-order roots correlated positively with the soil phenolic acid content. A Cox proportional hazards analysis revealed that soil conditions, root orders, season of root birth, and soil depth significantly affected fine-root longevity. These findings suggest that roots of different orders contribute unequally to the poplar plantation productivity.

Plant phenolic compounds (phenylpropanoids) act as defense chemicals against herbivores and can mediate ecosystem processes. Tropospheric ozone (O3) pollution alters concentrations of plant phenolics; however, little is known about how these phytochemicals respond to different levels of O3 exposure. Here, we investigated the effects of five different O3 exposure levels on foliar concentrations of phenylpropanoids (53 compounds in total) and antioxidative capacity in hybrid Populus (Populus euramericana cv. ‘74/76’) saplings grown in the presence of high or low soil nitrogen (N) load. Increasing O3 exposure initially increased and then decreased total concentrations of phenolic compounds, revealing a biphasic exposure-response profile (hormetic zone: 1.1–36.3 ppm h AOT40). This biphasic response pattern was driven by changes in a subset of phenylpropanoids with high antioxidative capacity (e.g. condensed tannins) but not in phenolics with low antioxidative capacity (e.g. salicinoids). The O3 exposure-response relationships of some phenylpropanoids (e.g. flavonoids and chlorogenic acids) varied in response to soil N, with hormesis occurring in high N soil but not in low N soil. Collectively, our findings indicated that plant phenolic compounds exhibit nonlinear responses to increasing O3 exposure, and that the responses vary in relation to phenolic compound class, antioxidative capacity, and soil nitrogen conditions. Our findings further suggest that the impact of O3 on ecological processes mediated by phenolics will be concentration-dependent, highlighting the complexity of the ecological effects of ground-level O3 pollution.

The effects of magnetized water irrigation on the growth and ionic movements of one-year-old potted seedlings of Populus × euramericana ‘Neva’ were investigated. A magnetic treatment device was used to treat the plants. The contents of K+, Na+, Ca2+, and Mg2+in leaves and roots were analyzed by atomic absorption spectrophotometry (AAS), and the fluxes of K+, Na+, Ca2+, Mg2+, and H+in mesophyll cells and in meristematic zones were measured using a noninvasive micro-test technique (NIMT) after 30 days of treatment. After 90 days, the plants were harvested, and their growth indices and root morphology were measured. The results showed that (i) compared with nonmagnetic treatments (NMT), the magnetic treatments (MT) led to higher K+and Mg2+contents and lower Ca2+content in roots and leaves, while the Na+content was lower and the K+/Na+ratio was higher; (ii) MT enhanced Na+efflux, increased H+influx, and decreased K+and Mg2+efflux compared with NMT; (iii) MT resulted in greater height, diameter, and leaf area of the plants and increased the length, surface area, and number of root tips compared with NMT; and (iv) stomatal conductance (Gs), net photosynthetic rate (Pn), intercellular CO2concentration (Ci), and water use efficiency (WUE) were increased in MT, whereas both transpiration rate (Tr) and stomatal limiting value (Ls) were decreased compared with NMT. The results indicate that the use of magnetized water can promote plant quality and regulate the ion absorption, transpiration, and distribution. Thus, MT is conducive to the re-establishment of ionic homeostatic mechanisms via ion-selective absorption and transportation under salt stress.

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Aims The relationship between rhizosphere process and fine root growth is very close but still obscure. In poplar plantation, phenolic acid rhizodeposition and soil nutrient availability were considered as two dominant factors of forest productivity decline. It is very hard to separate them in the field and they might show an interactive effect on fine root growth. The objective of this study is to examine the influence of phenolic acids and nitrogen on branch orders of poplar fine roots and to give a deeper insight into how the ecological process on root-soil interface affected fine root growth as well as plantation productivity. Methods The cuttings of health annual poplar seedlings (I-107, Populus × euramericana ‘Neva’) serve as experiment materials, and were cultivated under nine conditions, including three concentration of phenolic acids at 0X, 0.5X, 1.0X (here, X represented the contents of phenolic acids in the soil of poplar plantation) and three concentration of nitrogen at 0 mmol·L, 10 mmol·L, 20 mmol·L, based on Hoagland solution. The roots were all separated from poplar seedlings after 35 days, and 30 percent of total fine roots of every treatment were taken as fine root samples. These fine roots were grouped according to 1 to 5 branch orders, and then the morphological traits of each group of fine roots were scanned via root analyzer system (WinRHIZO, Regent Instruments Company, Quebec, Canada) including total length, surface area, volume and average diameter. Meanwhile, the dry mass of fine root samples of every order was measured to calculate specific root length (SRL), root tissue density 朱婉芮等: 酚酸和氮素交互作用下欧美杨 107细根形态特征 1199 doi: 10.17521/cjpe.2015.0116 (RTD). All data were analyzed via SPSS 17.0 software, and interactive effect of phenolic acids and nitrogen on roots was analyzed through univariate process module. Principal component analysis (PCA) and redundancy analysis (RDA) were conducted via Canoco 4.5 software. Important findings Under the conditions without phenolic acids application, the fine roots growth was significantly inhibited in deficiency and higher nitrogen treatments, especially for 1–3 order roots. Only specific root length appeared decreased with nitrogen level, and other traits of fine roots did not demonstrate linear relationship with nitrogen concentrations. Compared to 0.5X phenolic acids treatment, 1.0X phenolic acids significantly promoted the diameter and volume of 1–2 order roots (p < 0.05). Both phenolic acids and nitrogen demonstrated influence on poplar fine root traits. However, the diameter and volume of 1–2 order roots were significantly affected by phenolic acids, while the total length and surface area of 4–5 order roots was affected by nitrogen. Two way ANOVA showed that phenolic acids and nitrogen made a synergistic or antagonistic effect on morphological building of fine roots. Furthermore, PCA and RDA indicated that the interactive effects of phenolic acids and nitrogen led to significant differences among 1–3 order, 4th order and 5th order of poplar fine roots. The PC1 explained about 60.9 percent of root morphological variance, which was related to foraging traits of roots. The PC2 explained 25.3 percent of variance, which was related to root building properties. The response of poplar roots to phenolic acids and nitrogen was closely related to root order, and nitrogen played more influence on poplar roots than phenolic acids. Thus, phenolic acids and nitrogen level would affect many properties of root morphology and foraging in rhizosphere soil of poplar plantation. But nitrogen availability would serve as a dominant factor influencing root growth, and soil nutrient management should be critical to productivity maintenance of poplar plantation.

Odontotermes obesus (Rambur) is a widespread termite species in South Asia causing significant losses annually. Feeding preferences of O. obesus among 18 different wood species were studied in choice and no-choice bioassays conducted under laboratory and field conditions. Weight losses, wood consumption per individual, and survival rate were determined to evaluate feeding preferences of O. obesus. Populus euramericana and Tectona grandis were found to be the most susceptible and resistant woods, respectively. Nine different wood combinations were used in the bioassay under choice laboratory conditions. The maximum feeding of termites was recorded on M. indica and P. euramericana, whereas the minimum was noted on T. grandis and B. bamboo (2.06 and 43.9 mg), respectively. Under no-choice field conditions, the minimum feeding was recorded on T. grandis (8.9 mg) and the maximum on P. euramericana (47.9 mg). Under choice field conditions, O. obesus showed the maximum (82.6 mg) feeding on P. euramericana and th...

The poplar clones of Robusta and I-214 (Populus × euramericana) are characterized by fast growth and high quality biomass production. The calorific values for these poplar clones were determined, and modelling of calorific production of the entire poplar clone stands was performed. This research, dependent on age and site indexes, was conducted in four localities in Eastern Slovakia and seven in the western region of this country. Samples of bark, wood and small-wood with bark were excised from three tree stem areas and from two parts of the crown. No significant difference was observed between the two clones, with regard to either the biomass fraction or the location of the excised sample on the tree. The average calorific capacity of all biomass fractions was approximately 6.86-8.73 GJ m-3, with the lowest bark values emanating from the stem base. The mean annual calorific energy production for site indexes 40-20 after 17-26 years growth was 320-80 GJ ha-1 a-1, and this was calculable 2-3 years earlier in the I-214 clone than in Robusta. The energy use efficiency of these poplar clones was estimated at a maximum of 0.4-1.6% solar radiation utilization.

Five Populus × euramericana wood samples representing three different sites were selected and near infrared (NIR) spectra were obtained. For these sections, basis weight, brightness and three mechanical properties (tensile index, tearing index and bursting index) were determined by standard analytical methods. Calibrations were developed for each paper property using the NIR spectra, data on paper properties, using partial least squares (PLS) regression. The results show that the coefficients of correlation of calibration and validation for basis weight were 0.8824 and 0.8299, respectively; the standard error of calibration (SEC) and prediction (SEP) were 1.150 and 1.170, respectively. In testing for brightness, the correlation coefficient of calibration was 0.9621 and for validation 0.9612, while the SEC and SEP were 0.997 and 1.300, respectively; paper brightness and NIR spectroscopy were highly correlated. NIR spectroscopy can be used to predict tensile, tearing and bursting indices of paper samples rapidly. We found that the paper properties fitted by NIR and GB methods were highly correlated. The coefficients of correlation of calibration and validation for basis weight exceeded 0.8000, while the SEC and SEP were very small. These results reveal that the five paper properties of Populus × euramericana and those predicted by the NIR model were highly correlated. We conclude that the NIR models can be used for the prediction of paper properties.

Bait matrix of different treatments were evaluated against two termite species i.e. Odontotermes obesus and Coptotermes heimi both under laboratory and field conditions. Mean wood consumption in laboratory bioassays were investigated for 2, 4 and 6 weeks with maximum consumption was noted after 4 weeks. While, field experiment was conducted for 24 there was greater consumption of the loosely bound bait matrix compared to the tightly bound matrix. However, feeding was comparatively high in combinations with attractants. Overall, treated colonies experienced a 90-95% decrease in population size after 24 weeks of baiting. The queen in the royal chamber of the mound was found dead.

International audience; This paper presents an experimental method allowing 3D measurements of the geometry of a standing mature tree to be closely linked to the spatial distribution of internal wood properties. The accuracy of the geometrical information is assessed from repeated measurements performed on 10 mature poplar trees and demonstrates that wind is the most limiting factor. Since the method was developed to study the spatial distribution of tension wood, some pictures of the latter are presented. Furthermore, some preliminary relationships between variables derived from measurements such as the height, the local tree slope, the eccentricity of the tension wood area, or the eccentricity of the disc are discussed to illustrate the potential of the method.; Comment connecter la forme d'un arbre sur pied aux propriétés internes du bois : proposition d'une méthode expérimentale appliquée sur des peupliers. Cet article présente une méthode expérimentale de mesure de la géométrie tridimensionnelle d'un arbre sur pied mature permettant un couplage étroit avec la mesure des propriétés internes du bois. La précision de l'information géométrique est estimée à partir de mesures répétées sur 10 peupliers et met en évidence le vent comme principal facteur limitant. La méthode ayant été développée pour étudier la distribution spatiale du bois de tension, quelques illustrations de cette dernière sont présentées. En outre, des relations préliminaires liant des variables telles que la hauteur, l'inclinaison locale de l'arbre, l'excentricité de la zone de bois de tension ou l'excentricité de la rondelle sont discutées afin d'illustrer le potentiel de la méthode.

Development of leaf rust (Melampsora ciliata) in different species, hybrids and cultivars of poplar (Populus spp.) was studied in nursery-grown plants. Five different criteria were used to assess the disease development. The mean disease index on 10 August was 9.4% which increased to 70.0% on 10 October. The lowest disease index (5.5%) was recorded in P. yunnanensis whereas the maximum was recorded in P. × euramericana‘Rubra-Poiret’ (59.5%). The apparent infection rate per unit per day was highest in P. nigra × P. trichocarpa (9.7 × 10–2) whereas the minimum occurred in P. maximowiczii × P. berolinensis‘Oxford’ (3.3 × 10–2). The area under the disease progress curve was a maximum in P. × euramericana‘Rubra-Poiret’ (26.7) and a minimum in P. yunnanensis (1.6). Complete defoliation by the first half of October occurred in P. nigra × P. trichocarpa, which also had the maximum apparent infection rate and area under the disease progress curve. Inoculum production was highest in P. nigra × P. trichocarpa and lowest in P. maximowiczii × P. berolinensis‘Oxford’. Developpement de la rouille du peuplier a Melampsora ciliata en pepiniere, dans le nord-ouest de l’Hymalaya Le developpement de la rouille foliaire aMelampsora ciliata Barclay chez differentes especes, des hybrides et des cultivars de peuplier a eteetudie sur des plants en pepiniere. Cinq criteres ont ete utilises pour evaluer la maladie. L’indice moyen de maladie le 10 aout etait de 9,4% et de 70,0% le 10 octobre. L’indice le plus faible (5,5%) a ete observe chez Populus yunnanensis et le plus eleve chez P. × euramericana‘Rubra-Poiret’ (59,5%). Le taux d’infection apparente par unite foliaire et par jour a ete le plus eleve chez P. nigra × P. trichocarpa (9,7 × 10–2) et le plus faible chez P. maximowiczii ×P. berolinensis‘Oxford’ (3,3 × 10–2). La surface au dessous de la courbe de progression de maladie etait maximale chez P. × euramericana‘Rubra-Poiret’ (26,7%) et minimale chez P. yunnanensis (1,6%). La defoliation totale dans la premiere moitie d’octobre a eu lieu chez P. nigra × P. trichocarpa qui avait aussi le maximum de taux d’infection apparente et de surface sous la courbe de progression de maladie. La production d’inoculum etait la plus forte chez P. nigra × P. trichocarpa et la plus faible chez P. maximowiczii × P. berolinensis‘Oxford’. Entwicklung von Melampsora ciliata auf Pappelstecklingen in einer Baumschule im Nordwest-Himalaja An Stecklingen verschiedener Pappelarten, -hybriden und -sorten wurde die Entwicklung des Blattrostes Melampsora ciliata anhand von funf Parametern registriert. Der mittlere Krankheitsindex betrug am 10. August 9,4% und nahm bis zum 10. Oktober auf 70% zu. Der kleinste Indexwert wurde bei P. yunnanensis registriert, der grosste bei P. × euramericana‘Rubra-Poiret’ (59,5%). Die anhand der Symptome erkennbare Infektionsrate pro Einheit und Tag war bei P. nigra × P. trichocarpa am hochsten (9,7 × 10–2) und bei P. maximowiczii × P. berolinensis‘Oxford’ am geringsten (3,3 × 10–2). Die Flache unter der Kurve des Krankheitsverlaufs war bei P. × euramericana‘Rubra-Poiret’ am grossten (26,7) und bei P. yunnanensis am kleinsten (1,6). Eine vollstandige Entlaubung in der ersten Oktoberhalfte trat bei P. nigra × P. trichocarpa ein, die ebenfalls eine sehr hohe Infektionsrate und einen sehr progressiven Krankheitsverlauf aufwies. Die Inokulumproduktion war auf dieser Hybridpappel am hochsten, am geringsten war sie bei P. maximowiczii × P. berolinensis‘Oxford’.

In a greenhouse, under controlled conditions, young shoots, taken from poplar cuttings (Populus euramericana (Dole) Guinier cv. Ghoy), were artificially bent to quantify the modifications of physic...

L'effet de la competition sur la performance et la reponse morphologique du peuplier hybride DN-74 (Populus deltoides × nigra) a ete examine en faisant varier la densite de 4 444 tiges ha -1 a 40 000 tiges ha -1 . La croissance en diametre au niveau du collet etait inversement reliee a l'intensite de la competition: le diametre au niveau du collet a diminue de moitie de la plus faible densite a la plus elevee apres seulement quatre saisons de croissance. La largeur de la cime, le rapport de la longueur de la cime sur la hauteur de la tige, la biomasse foliaire et la surface foliaire ont diminue de facon significative avec un accroissement de la densite. Cependant, le rapport de la largeur de la cime sur la longueur de la cime, la surface foliaire projetee et le rapport de la surface foliaire sur la biomasse foliaire et des tiges n'ont pas varie de facon significative avec la densite, et la surface foliaire specifique a diminue avec le degre de fermeture du couvert et la profondeur dans le couvert, ce qui indique que cet hybride se caracterise par un degre eleve de plasticite quand il est soumis a la competition. Les contenus en elements nutritifs du feuillage et des tiges n'ont pas varie de facon appreciable avec l'intensite de la competition.

Les auteurs ont transforme genetiquement un clone hybride de peuplier nomme « Ogy » (Populus x euramericana) avec le gene (pin2) codant pour l'inhibiteur de la proteinase de classe II (PI II) de la pomme de terre afin de verifier l'importance des proteinases de la serine dans les interactions hotes-pathogenes et hotes-insectes. Le produit de ce gene, PI II, est un inhibiteur specifique a la trypsine et a la chymotrypsine. Les genotypes transformes furent obtenus a l'aide d'un systeme binaire du vecteur Agrobacterium muni d'un plasmide Ti desarme (EHA 101) et du plasmide pRT104 contenant le gene pin2 assujetti au controle regulateur du promoteur 35S du CaMV, ainsi que d'un gene de selection codant pour la neomycine phosphotransferase II (NPT Il). Des tiges presumement transformees provenant de la co-culture de feuilles furent selectionnees a l'aide de trois tests differents de toxicite a la kanamycine. A partir de 431 tiges issues de la co-culture, 10 plantules furent choisies et soumises a l'analyse des acides nucleiques et des proteines. L'analyse de l'ADN (hybridations Southern et PCR) ainsi que les hybridations de proteines sur gel (hybridations Western) ont confirme l'integration du gene pin2 et son expression dans la lignee transformee TR5.

Nous avons explore la possibilite d'utiliser une estimation de type Monte-Carlo comme alternative aux techniques traditionnelles d'inventaires par echantillonnage pour l'estimation de la photosynthese journaliere et saisonniere de peupliers clonaux entiers âges de 1 an. Nous avons applique plusieurs techniques dites de reduction de variance au probleme de l'estimation, et les avons comparees a l'aide de la racine des carres moyens de l'erreur. Nous avons aussi considere le gain de precision par rapport a l'estimateur par expansion au premier terme (l'estimation Monte Carlo sous sa forme la plus simple). La variance a ete reduite en ajustant a la courbe de photosynthese une fonction connue et simple a integrer. Les estimateurs sont non biaises, quel que soit l'ajustement de la fonction. Nous demontrons comment ces methodes de reduction de variance peuvent etre utilisees pour ameliorer la precision de l'estimation de la photosynthese journaliere et saisonniere de l'arbre entier. Ces methodes sont des alternatives utiles aux methodes actuelles d'echantillonnage, methodes qui ont un potentiel eleve de biais et d'erreur

The sex attractant of the poplar clearwing moth, Paranthrene tabaniformis Rott. (Lep., Sesiidae) was applied during 3 years in ‘lure and kill’ and ‘mass trapping’ experiments to prevent infestations in young poplar plantations. Although the number of males was reduced, there was no statistically significant decrease in infestations by comparison with untreated plots. The sex attractant was also used to study the moth's flight behaviour. In poplar stands with trees about 15 m tall, the numbers of males captured, increased with increasing height of the traps. In young plantations, most (90 %) males fly at lower levels, up to 3.0 m, roaming along the tops of trees and other vegetation. Zusammenfassung Untersuchungen uber die Wirkung des Sexuallockstoffes von Paranthrene tabaniformis Rott. (Lep., Sesiidae) Der Sexualduftstoff des Pappelglasfluglers Paranthrene tabaniformis Rott. wurde 3 Jahre lang in ‘Jure and kill’ - sowie ‘mass trapping’-Experimenten angewandt, um den Befall junger Pappelpflanzungen durch den Schadling zu verhindern. Obwohl die Zahl der Mannchen reduziert wurde, ergab sich keine gesicherte Abnahme des Befalls im Vergleich zu unbehandelten Parzellen. Weiterhin wurde der Duftstoff angewandt, um das Flugverhalten der Falter zu studieren. In Pappelbestanden mit ca. 15 m hohen Baumen nahm die Zahl der gefangenen Mannchen mit zunehmender Hohe der Fallenanbringung zu. In Jungpflanzungen flogen die meisten (90 %) Mannchen in niedrigerer Hohe (bis 3 m) um die Gipfel der jungen Baume herum oder um andere Pflanzen.

Callus cultures of Populus×euramericana cv. ‘NL-B-132’ derived from stem and leaf tissue were compared for their content of abscisic acid and defense reactions against the basidiomycete Phaeolus schweinitzii. The callus from stems showed higher ABA-contents and a more pronounced defense reaction in comparison with leaf callus.

International audience; Using cytological methods and SSR DNA marker analysis, this study revealed the formation mechanisms and the genetic constitutions of the 2n pollen in Populus × euramericana (Dode) Guinier and P. × popularis.* In P. × euramericana (Dode) Guinier, four abnormalities in microsporogenesis were observed: parallel spindle, fused spindle, tripolar spindle and premature cytokinesis. The first three can lead to first-division restitution (FDR) 2n pollen formation and the last one can form second-division restitution (SDR) 2n pollen. The SSR marker analysis results of parents and their tetraploidy filial generation confirmed that the genetic constitution of 2n pollen produced by P. × euramericana (Dode) Guinier was FDR.* In P. × popularis, three of these abnormalities were observed: parallel spindle, fused spindle and premature cytokinesis. The SSR marker analysis results showed the genetic constitution of 2n pollen produced by P. × popularis was SDR. Natural 2n female gametes in P. × euramericana (Dode) Guinier are reported for the first time. SSR analysis indicated that natural 2n female gametes of P. × euramericana (Dode) Guinier did exist and were fertile, which could be FDR genetic constitution.* The results from this study showed a great potential for using 2n gametes to produce polyploid poplar clones, which can be used effectively for polyploid breeding for poplar species in the section Aigeiros.; En utilisant des méthodes cytologiques et des analyses avec des marqueurs SSR, cette étude a révélé les mécanismes de formation et la constitution génétique du pollen 2n chez Populus × euramericana (Dode) Guinier et P. × popularis. * Chez P. × euramericana (Dode) Guinier, quatre anomalies dans la microsporogénèse ont été observées: en parallèle broche, broche fusion, tripolaire broche et une cytokinèse prématurée. Les trois premiers peuvent entraîner une première division restitution (FDR) de formation du pollen 2n et le dernier peut former une deuxième division de restitution (SDR) du pollen 2n. Les résultats de l'analyse des marqueurs SSR des parents et de leur descendanta tetraploides ont confirmé que la constitution génétique du pollen 2n produit par P. × euramericana (Dode) Guinier a été FDR. * Dans P. × popularis, trois de ces anomalies ont été observées: en parallèle broche, broche fusion et cytokinèse prématurée. Les résultats de l'analyse de marqueurs SSR ont montré que la constitution génétique du pollen 2n produit par P. × popularis a été SDR. Les gamètes naturelles femelles 2n chez P. × euramericana (Dode) Guinier ont été signalés pour la première fois. Les analyses SSR ont montré que les gamètes naturels femelles 2n de P. × euramericana (Dode) Guinier existaient et étaient fertiles, cela pourrait être la constitution génétique FDR. * Les résultats de cette étude ont montré le grand potentiel de l'utilisation des gamètes 2n pour produire des clones de peuplier polyploïdes, cela peut être utilisé efficacement pour la sélection de polyploïdes pour des espèces de peuplier de la section Aigeiros.

In foliage of Pinus sylvestris, Populus euramericana, and Picea abies the fatty acid composition was analyzed. Whereas clonal material of pine and poplar in controlled ozone fumigations did not show any significant differences as compared to controls, such differences were obtained in field-grown spruces showing needle loss

Studies have been carried out on the causes of wood deterioration in poplars following decline due to water stress in Italy. The incidence of 21 wood decay fungi, among which Trametes trogii Berk, is the most widely spread, is reported. Some suggestions for reducing the damage are offered.

La pyrolyse du bois a basse temperature conduit a l'obtention d'un produit solide, intermediaire entre le bois et le charbon de bois: le bois torrefie. L'objet de cette etude est l'optimisation du procede et la determination des caracteristiques du materiau et ses limites d'utilisation. Les parametres de traitement etudies sont le temps de palier intermediaire a 150°C , la temperature finale (entre 210 et 230°C), le temps de palier a la temperature finale, la presence ou non de vapeur d'eau saturee. Certaines caracteristiques du materiau ont ete mesurees pour decrire le comportement physique et mecanique du bois torrefie: humidite, retrait, reprise d'eau, resistance a la compression axiale et a la flexion statique, module d'elasticite. Des tests de resistance a differents agents biologiques (champignons et insectes) ont egalement ete realises pour evaluer la durabilite conferee par le traitement thermique. Les resultats montrent que les proprietes acquises par le bois a travers un traitement de torrefaction sont tres sensibles aux parametres du procede, et en particulier le temps de sejour a la temperature finale et la presence de vapeur d'eau. Le traitement doit etre adapte a chaque essence pour obtenir un compromis entre caracteristique mecanique d'une part et stabilite dimensionnelle et durabilite d'autre part. (Resume d'auteur)

International audience; Stem diameter, total plant height and number of sylleptic branches of three poplar (Populus) genotypes were followed during the first growing season of a high density intensively cultured plantation (in Central Italy) both under ambient CO$_2$ (Control) and under elevated atmospheric CO$_2$ (550 ppm) using the FACE technique. The three poplar genotypes belonged to different species of Populus alba L., Populus nigra L. and Populus x euramericana Dode (Guinier). All three genotypes responded by an enhanced growth performance but the extent of their response to the FACE treatment was different. A stem volume index was calculated considering the stem composed by a truncated cone in the lower part and by a cone in the upper part. At the end of the first growing season, stem volume index was increased in the FACE treatment by 54% to 79% as compared to Control treatment, depending on the genotype. This increased stem volume index was caused by an increase of basal stem diameter rather than by an enhancement of plant height. Number of sylleptic branches was stimulated by more than 35% in the P. nigra genotype. The results confirm the optimal performance of this new POPFACE experiment and show the positive response of this fast-growing tree species to elevated CO$_2$ conditions at an ecosystem scale even if considering the genotypic differences.; Performance de croissance de plants de Populus exposés à une atmosphère enrichie en dioxide de carbone durant la première saison de croissance dans l'expérimentation POPFACE. Le diamètre du tronc, la hauteur totale et le nombre des branches sylleptiques de trois génotypes de peuplier (Populus) ont été suivis durant la première saison de croissance d'une plantation de haute densité en culture intensive (en Italie Centrale), à la fois sous air ambiant (350 ppm, plantes témoins), et sous atmosphère enrichie en CO$_2$ (550 ppm) en utilisant la technique FACE. Les trois génotypes de peuplier utilisés font partie d'espèces différentes : Populus alba L., Populus nigra L. et Populus x euramericana Dode (Guinier). Les trois génotypes ont tous répondu au traitement FACE par une augmentation de la croissance, mais avec des intensité différentes. Un index de volume du tronc a été calculé en considérant le tronc comme étant composé d'un cône tronqué pour sa partie inférieure, et d'un cône pour la partie supérieure. À la fin de la saison de croissance, l'index de volume du tronc était supérieur de 54 % à 79 % , en fonction du génotype, pour le traitement FACE par rapport aux plants témoins. Cette augmentation de l'index de volume du tronc est principalement due à l'augmentation du diamètre basal des troncs, plus qu'à l'augmentation de la hauteur des plants. Le nombre des branches sylleptiques a été augmenté de plus de 35 % par le traitement FACE, pour le génotype Populus nigra. Ces résultats, tout en illustrant le bon fonctionnement du nouveau dispositif expérimental POPFACE, confirment, à l'échelle de l'écosystème, qu'une atmosphère enrichie en CO$_2$ a pour effet une augmentation de la croissance de ces espèces ligneuses à croissance rapide.

Two Euramerican poplar clones, ‘I-214’and ‘I-45/51′, were badly damaged by frost cracks in 1981 and 1985. Thermocouples attached to 12 trees showed that clone ‘I-45/51’was more resistant to winter and late frosts, possibly due to its significantly thicker and rougher bark in comparison to ‘I-214′.

Gross heat of combustion using an oxygen bomb calorimeter at ovendry condition was determined and analyzed for 2-year-old sprouts of 10 hybrid Populus L. clones of diverse genetic background. Values showed a clonal range of 14% from a low of 4357 cal g−1 (1 cal = 4.1868 J) to a high of 4955 cal g−1. Clones of section Aigeiros Duby (cottonwood) showed significantly greater energy potential than representatives of section Leuce Duby (aspens). There was a significant interaction of clones × sprouts indicating environmental conditions or manner of growth may influence the magnitude of clonal differences. No relationship was found between potential energy and stem specific gravity.Sample discs from a 5-year-old P. tremuloides stem and an 8-year-old P. × euramericana cl. DN-30 were also analyzed by individual growth rings. No relationship was found with density. Outer bark (rhytidome) showed higher calorific values than inner bark (secondary phloem). The possible implication in breeding poplars for energy production is discussed.

Three collections of Melampsora larici-populina Kleb. originating from Belgium, France and the Netherlands were compared for their pathogenicity on eleven poplar clones. Qualitative type reactions suggest the existence of two pathogenic races designated E1 and E2. E2 is able to infect some clones previously considered to be resistant.

Live-trapping and radio-tracking were used to monitor the movements of brush-tailed possums in and around an erosion-control planting of poplars. Possums' use of the planted area was monitored by traffic counters and by marking (with Rhodamine B dye) possums which climbed the poplars. The extent of browse damage to the poplars was also recorded. Over a period of 20 months, 358 individuals were trapped, marked, and released, and 50 were fitted with radio transmitter collars. The study area was mapped into nine 100-m-wide annular zones radiating out from the focus, Zone 0, which contained the poplars. Seventy percent of possums assigned to Zone 1 were caught in Zone 0, but only 24%, 5%, and 0% assigned to Zones 2, 3, and 4–8 respectively were caught in Zone 0. Trapping and radio-tracking revealed no increase in the use of the planted area during the spring flush although the poplars were being damaged. Traces of Rhodamine B dye on the possums showed that 87% of animals caught in Zone 0 had visited ...