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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.

The effects of technical, technological, and material factors affecting the size of juvenile poplar wood chips were evaluated. Each analysis was performed on two species of poplar, namely natural poplar Populus tremula L. and plantation poplar clones Populus euramericana Serotina, and on juvenile and mature wood within each poplar species. A cutter with angular geometry was selected for the face milling:  = 55° (angle of cutting wedge),  = 15° (rake angle). The cutting conditions were a feed rate of vf = 2.5 and 15 m·min-1, cutting speed of vc = 30 m·s-1, 45 m·s-1, and 60 m·s-1, and the depth of cut ap = 1 mm. An image analysis of the size of the largest and smallest fraction was performed. Most of the chips generated during the face milling of poplar wood were classified as flat grain wood. A small percentage of the generated chips could be included in the group of rod-shaped fibrous bulk particles with a considerable extension in one direction (smaller fractions generated at a feed rate of 2.5 m·min-1, and at the finest fractions- dust generated in all of the combinations of technical and technological parameters).

An efficient regeneration protocol for stem disc culture of Populus euramericana, which is important species for bioenergy resource in agroforestry, was established. The number of explants that were obtained and the number of explants that regenerated varied with the genotypes. However, in all the genotypes, stem disc culture produced more regenerated shoots than did in axillary bud culture. A comparison of the effects of cytokinin type and concentration on shoot regeneration in different explants (i.e., petiole, leaf, and root segments of P. euramericana) revealed that a concentration of 0.002 mg l-1 thidiazuron (TDZ) used on petiole segments resulted in the greatest shoot regeneration (95.83%). The hormonal requirements for the greatest shoot regeneration in the three explant types varied. Different concentrations of AgNO3 and CoCl2 were added separately to the medium to stop the yellowing and subsequent necrosis of the regenerated shoots. Lower concentrations (3 and 5 mg l-1) of these compounds improved shoot regeneration and elongation, compared with the control. The in vitro-regenerated shoots were transferred to rooting medium and subsequently acclimatized. The highly efficient regeneration system of P. euramericana reported here can be used for mass propagation of this recalcitrant for regeneration, economically important tree species.

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.

La bacteria Lonsdalea quercina (ex Brenneria quercina) ssp. populi ha sido recientemente descrita en Hungría y China como una nueva subespecie causante del chancro de la corteza del chopo. Los árboles afectados presentan chancros longitudinales en el tronco, de los que fluyen inicialmente exudados acuosos oscuros, seguidos de abundantes exudados espumosos de color blanco. Bajo la corteza se observa una masa cremosa de color blanquecino. Se produce un debilitamiento de los árboles y aquellos más severamente afectados pueden llegar a morir. En este trabajo se presenta la primera detección de L. quercina ssp. populien España y se describen los métodos de diagnóstico utilizados.

Lonsdalea quercina (ex Brenneria quercina) subsp. populi es una bacteria recientemente identificada en Hungría y China como una nueva subespecie causante del chancro de la corteza del chopo. Los árboles afectados presentan chancros longitudinales en el tronco, de los que fluyen abundantes exudados espumosos de color blanco y exudados acuosos oscuros que tiñen la corteza. Los chopos afectados muestran un debilitamiento generalizado. En España se han localizado choperas con síntomas similares y se ha identificado L. quercina subsp. populi como el agente causal de los mismos. En este trabajo se presenta la primera detección de esta bacteria en España y se describen los métodos de diagnóstico e identificación utilizados. Esta nueva bacteriosis podría tener un impacto económico importante, siendo necesario evaluar las pérdidas causadas y realizar nuevas prospecciones para determinar su distribución en el país.

Plantations of hybrid poplars adapted to relatively poor soils and cold conditions are being established in abandoned fields and forest sites in southern Quebec. Hybrids of Populus maximowiczii are well adapted to these sites but little is known about their nutritional requirements. The objectives of this study were to develop nutritional norms (CVA, DRIS, CND) for three of these hybrids: 915508, Populus euramericana or canadensis X Populus maximowiczii; 3729, Populus nigra X Populus maximowiczii; and 915303, Populus maximowiczii X Populus balsamifera, and to apply the norms on some sites recently planted in southern Quebec. Six plantations (two per clone) were used for the determination of nutritional norms. In each plantation, individual trees were fertilized with nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) according to a factorial design with three levels of application for each nutrient (35 = 243 treatments). Tree diameter and height, unit foliar mass and foliar chemi...

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.

The relationships between above-ground stem, branch, leaf masses and stand density index (SDI) were analysed in Populus×euramericana (Dode) Guinier stands in Jiangsu Province, China. The allometric equations developed in this study accurately estimated masses of above-ground and specific above-ground tree components in stands with different SDIs. The relationship between the mean above-ground mass w and the ratio of stem to the above-ground (wS/w) was examined. With increasing w, the stem mass ratio wS/w increased. Mean masses of above-ground and tree components decreased significantly with increasing SDI at age 9 years, indicating the presence of competition-induced limitations to growth. The mean above-ground mass‐SDI and mean component mass‐SDI were strongly correlated with above-ground mass-SDI and tree component mass‐SDI, respectively. An equation describing the relationship between the mean leaf area u and SDI was developed, which fitted well for the u-SDI data. Stem mass increment exponentially increased with increasing leaf area index.

Grading tests were performed on 338 poplar wood samples (Populus × euramericana I-214) with dimensions of 150×50 mm2, 150×80 mm2, and 200×100 mm2 prepared for structural utilization. The non-destructive testing methods included ultrasound (Sylvatest) and induced vibrations (Portable Lumber Grader) combined with visual grading criteria. Additionally, screw withdrawal resistance was tested by the instrument Fakopp. These results were compared with those obtained by a four-point bending test according to the EN 408 (2004) standard. Ultrasound and induced vibrations overestimated the quality of this type of wood. Correlation equations are proposed to determine the true characteristics for each testing method. It can be concluded that poplar timber from clone I-214 has acceptable flexural strength, but a comparatively low elastic modulus, whereby it is not graded within a high strength class according to the EN 338 (2009) standard.

The area covered by plantations of hybrid poplar in Europe is increasing greatly because of the high profitability of these trees. However, the productivity varies widely depending on nutritional status, and it is therefore essential to identify the limiting nutrients. The aims of this study were (a) to identify the main nutrients limiting the growth and vitality of monoclonal poplar (Populus × euramericana) plantations and (b) to develop a means of early detection of nutrition-related problems in growth, based on visual crown conditions (crown transparency, VCT, and visual crown discoloration, VCD). The study was carried out in one of the most suitable areas for this species in Southern Europe. Thirty-two Populus × euramericana (clone I-214) stands displaying different levels of decline were selected for study, and tree growth, nutritional status (soil properties and foliar nutrient concentrations) and crown conditions were assessed. The stands, which were growing in soils with high contents of coarse fragments, displayed low growth rates, poor crown conditions and deficiencies in Fe, B, N, P, K, and to a lesser extent, Zn and Cu. The deficiencies increased with the age of the stand, presumably because of the higher nutrient demand in older trees. Visual crown conditions were related to growth rates and nutritional status. Predictive models were developed to relate crown conditions to the nutritional status identified by analysis of soil properties and foliar concentrations of nutrients.

Hydroxycinnamoyl-coenzyme A shikimate/quinate hydroxycinnamoyltransferase (HCT), PeHCT was cloned from Populus euramericana. The predicted amino acid sequence revealed that PeHCT contained a conserved HXXXDG motif that was found in acyltransferase. The in vitro substrate was determined using recombinant PeHCT. The recombinant PeHCT showed substrate-specificity towards shikimic acid. In addition, PeHCT displayed higher expression in the stem than in the leaf, and its expression increased during the growth stage of the leaf. Results indicate PeHCT could be involved in lignin biosynthesis by formation of p-coumaroyl shikimate.

Growth and timber production of 28 poplar clones were evaluated. A set of clones was derived from 14 clones newly bred in Forestry and Game Management Research Institute in the Czech Republic, eight well-known cultivars of Populus × euroamericana planted in Europe and imported to the Czech Republic, two standard cultivars 'I-214' and 'Robusta' (Populus × euroamericana). Four clones of Populus deltoides were added to the test set. Tree spacing was 4 × 4 m. Stem diameter, tree height and stem volume production were evaluated in 6-years-old trees. Based on the results, it was concluded that the yield of four clones was higher than that of standard cultivar 'I-214'. Standing volume of two P. deltoides clones and one new Czech P. × euroamericana clone varied in the range of 77–121 m3·ha–1.

In previous experiments elevated but sub-symptomatic applications of Zn (0.1 mM and 1 mM) caused impairments in growth parameters and photosynthetic performance of Populus × euramericana (Dode) Guinier clone I-214. The aim of this work was to evaluate leaf morphological and anatomical traits in this clone in response to the same Zn concentrations. The results showed that Zn treatments induced variations in leaf dry mass, area, mesophyll thickness, intercellular spaces, stomatal density and size. Stronger modifications, especially concerning stomata characteristics induced by 1 mM Zn, were consistent with physiological impairments while those induced by 0.1 mM Zn suggested a compensatory strategy for maintaining functional integrity.

The lipophilic extractives in stemwood and bark from three different heights of Populus × euramericana “Guariento” were analyzed. The bark samples, especially from 4 and 8 meters height, contained much more extractives than the stemwood samples. The lipophilic extractives identified by Gas Chromatography–Mass Spectroscopy (GC-MS) were composed of five component groups (i.e. triglycerides, steryl esters, free fatty acids, sterols, and free fatty alcohols both in the stemwood and bark). Besides ferulic acid esters, α-amyrin and its esters, 4-hydroxycinnamic acid esters of fatty alcohols were also identified in the stemwood and bark. Small amounts of alkanes and oligomeric or polymeric material with higher molar mass than triglycerides were present only in the bark. Glycerides, mainly triglycerides, were the largest component group of the lipophilic extractives. The high proportion of short-chain fatty acids released after alkaline hydrolysis are beneficial when removing pitch particles or fatty aci...

Particleboards were produced from three-year-old poplar clones (e.g., Populus euramericana.costanzo, Populus euramericana. 561.41, Populus euramericana triplo, Populus euramericana vernirubensis, Populus euramericana marilandica, Populus euramericana. I-214, Populus deltoides 77.51, Populus trichocarpa, Populus nigra. betulifolia). One-layer laboratory particleboards were made with the above materials, with, board density of 0.7 gr/cm3, the resin type of (UF), a hardener content of (1%), a hardener type of (NH 4Cl), a press pressure of 30 kg/cm2, and a press temperature of 160°C. Modulus of elasticity (MOE) and modulus of rupture (MOR), internal bond strength (IB). Thickness swelling of the specimens were tested according to EN Standard. Overall results showed that most panels made from above materials exceeded the EN Standards for IB, MOE, and MOR. However, thickness swelling (TS) values were higher (poor) than requirements. The highest MOR, MOE, IB were reached with P.e. costanzo, P.e. 561.41, P.e. vernirubensis and P. trichocarpa poplar clones. The lowest TS 2 h and TS 24 h were reached with P.e. 561.41 and I-214 of the three-year-old poplar clones. Most types of panels made in this study covered the MOE, MOR, and IB strength requirements for interior fitments stated in the EN Standards. Nevertheless, the TS of the panels were very poor. Poplar clone panels are suitable for interior decoration (furniture, wall, and ceiling paneling).

The competition–density (C–D) effect for non-self-thinning Populus deltoides and Populus × euramericana plantations from 3 to 9 years was analyzed using the reciprocal equation of the C–D effect. The C–D effect was well described by the reciprocal equation, and with the progress of time the C–D curve, on logarithmic coordinates, of the P. × euramericana plantations shifted upward faster than that of the P. deltoides plantations. With increasing physical time t, the biological time τ, i.e. the integral from zero to t of the coefficient of growth λ(t) in the general logistic curve with respect to t, increased rapidly during early growth stages and the increases in τ gradually became slow during later growth stages. This trend was more evident in the P. deltoides plantations than in the P. × euramericana plantations. The coefficients A and B included in the reciprocal equation were calculated at each growth stage. With increasing τ, the coefficient A, the reciprocal of which means the asymptote of yield (=wρ) at a given growth stage, increased abruptly to a maximum value and then tended to decrease gradually to a constant level. On the other hand, the coefficient B, the reciprocal of which means the asymptote of mean stem volume at a given growth stage, decreased exponentially and tended to be close to zero with increasing τ. The λ(t) decreased with increasing stand age, whereas the final yield Y(t) defined as W(t) ρ, where W(t) is the asymptote of w in the general logistic growth curve, increased gradually with increasing stand age. The differences in coefficients A, B, and λ(t) between the two species were reported.

Nous avons étudié la réponse à la sécheresse de deux génotypes de peuplier euraméricain(Carpaccio et I214) et deux génotypes de peuplier noir (6J29 et N38). Nos mesures des paramètres de croissance ainsi que des échanges gazeux foliaires, nous ont permis de voir les facteurs déterminant l’efficience d’utilisation de l’eau intrinsèque au sein de ces génotypes mais également d’estimer l’effet de la sécheresse sur leur croissance. Nos résultats ont montré que les peupliers euraméricains croissent mieux que les peupliers noirs et que le génotype Carpaccio alliait à la fois une bonne croissance et une bonne efficience d’utilisation de intrinsèque.

Dans le cadre des études de l'équipe PhysioDiv sur les relations entre efficience d'utilisation de l'eau et productivité, une expérience estactuellement menée sur quatre génotypes de peuplier, de tolérance contrastée à la sécheresse, plantés à la pépinière du centre INRA de Champenoux. Le but de l'expérimentation est de comparer les résultats obtenus (sur certains traits qui contrôlent l'efficience d'utilisation de l'eau) en serres, sur les mêmes génotypes, avec ceux de la pépinière. Mon stage aconsisté à suivre les échanges gazeux foliaires (assimilation nette de CO2, conductance stomatique à la vapeur d'eau, efficience d'utilisation de l'eau intrinsèque) ainsi que la croissance (hauteur, diamètre, volume). Des cinétiques journalières de mesures ont été réalisées. Ces résultatssontmis en relation avec ceux déjà obtenus en 2015.

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.

Studies on Populus ×euramericana (Dode) Guinier cv. ‘Robusta’ wereconducted to examine the rooting behaviour and changes in water potentialduringrooting, as influenced by the initial water potential of the cutting at twosoilwater potentials (−0.006 and −0.06 MPa). Differencesinthe initial water potential of the cuttings was achieved by three pretreatmentsi.e., fresh, soaked and dried. Initial Ψshoot was −1.45,−0.10 and −2.10 MPa in fresh, soaked and driedcuttings, respectively. Soil moisture had a major effect on rooting. Waterstressed cuttings took a longer time to root and had fewer roots. Pre-soakingofcuttings stimulated rooting particularly under the drier soil moistureconditions. Initially the water potential of cuttings decreased with time andwith the formation of roots it stabilized in all the pretreatments.Resistance-to-flow measurements suggested the development of tyloses and theestablishment of new xylem. No relationship was evident between stomatalresistance of leaves and water potential of cuttings. The starch content of thestem cuttings decreased significantly with time irrespective of treatment.

Relatively little is known about the influences of growing-season background ozone (O3) concentrations on leaf cuticles and foliar water loss. Using fumigation chambers, leaf wettability and foliar water loss were studied in two poplar species, Populus nigra and P. euramericana, and a conifer, Pseudotsuga menziesii, under three O3 regimes; control (approx. 1 ppbv O3), urban O3 exposure (13-41 ppbv O3), and montane O3 exposure (30-45 ppbv O3). Urban O3 exposure delayed a decrease in droplet contact angles over time in Populus leaves by 2-4 wk, and decreased droplet contact angles of P. menziesii foliage. Ozone exposure increased foliar water loss and minimal conductance to water vapour for P. euramericana, but not P. nigra and P. menziesii. Both Populus species had lower photosynthetic biomass in O3 treatments, due to production of fewer new leaves, premature leaf abscission and decreased leaf size (P. euramericana only). Leaf abscission was preceded by foliar injury symptoms characteristic of O3 exposure. Results suggest that exposure to [O3] common during the growing season can increase water loss in Populus saplings, but this effect might be offset by decreased foliar biomass. Importantly, responses were highly species specific in a given O3 treatment.

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...

Young shoots from poplar cuttings (Populus euramericana cv ʻGhoyʼ) were artificially inclined to 30° from vertical to quantify the anatomical modifications induced by this gravitational stimulus. At the end of the growing season, the tension wood tissue (from the upper face of the inclined axis) was compared to the opposite wood tissue (from the lower face), with radial position taken into account. On isolated elements after maceration, fibres and vessels were significantly longer in tension wood tissue. In the cross section, the gelatinous fibres had a smaller radial diameter than normal fibres in opposite wood. Vessel frequency and porosity were significantly lower in tension wood than in opposite wood. Solitary vessels in tension wood were less circular in cross section than in opposite wood, but their surface area did not differ. Rays were more numerous in tension wood than in opposite wood but their height did not differ between the two tissue types. Finally, there was a negative correlation between the proportion of vessel lumina (lowest in tension wood) and the proportion of fibre lumina including the G layer. The very controlled nature of this experiment (greenhouse, young clonal material, detailed anatomical observations within one growth ring) and the image analysis technology (allowing a large number of observations) enabled us to draw conclusions that may not have been seen in less-controlled experiments and /or those with smaller sample sizes.

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.

Curved laminated veneer lumber (LVL) is manufactured from glue-coated pieces of rotary-cut veneers assembled and pressed between molds. In this study, curved LVLs were produced from two fast-growing wood species such as massion pine (Pinus massoniana Lamb.) and poplar (Populus euramericana CV. I.) for use in furniture. In addition to the applicability of the two wood species used, the optimum technological conditions of curved LVL production with radiofrequency (RF) heating and the physical and mechanical properties of curved LVL were investigated. The results are as follows: (1) Curved LVL made from massion pine and fast-growing poplar shows excellent mechanical properties. These fast-growing wood species are suitable for curved LVL being used as furniture structural members. (2) The mechanical properties of curved LVL are affected by frequency, voltage, RF application time, and moisture content, with the RF application time and moisture content having more important effects on the mechanical properties than the frequency and the voltage. (3) The mechanical properties of curved LVL increase with a linear increase in the density of curved LVL.

Cet article analyse l'evapotranspiration et la conductance du couvert pour la vapeur d'eau de trois peuplements forestiers aux Pays-Bas: pin, meleze et peuplier. Les taux maximaux d'evaporation sont du meme ordre de grandeur et etaient proches de l'evaporation d'equilibre pour des surfaces importantes. Il existe une relation etroite entre l'energie disponible et l'evapotranspiration pour le peuplier, et moins forte pour le pin ou le meleze. L'evapotranspiration moyenne des peuplements est la plus elevee pour le peuplier et la plus faible pour les pins. Les conductances maximales de couvert sont rangees dans le meme ordre: celle du peuplier montre la plus forte valeur, 55 mm s -1 , celle du meleze une valeur intermediaire, 31 mm s -1 , et celle du pin est la plus faible, 28 mm s -1 . Le controle stomatique est le plus fort chez le pin et le plus faible chez le peuplier. La conductance des trois peuplements montre une forte decroissance lineaire avec le deficit de saturation de l'air jusqu'a environ 8 a 10 g kg -1 , puis une decroissance plus lente au-dela. Pour le pin et le meleze la conductance stomatique atteint 50 % de son maximum pour un rayonnement global de 150 W m -2 , alors que le peuplier montre une augmentation moins rapide. Les conductances maximales chez le pin trouvees ici correspondent bien aux valeurs publiees. Celles du meleze et du peuplier sont elevees par rapport aux donnees de la litterature. Cela est peut-etre du a la longue duree de la periode de mesure de cette etude, ce qui augmente la probabilite d'observer des valeurs exceptionnellement fortes. Les resultats montrent aussi que des differences importantes de consommation en eau par les forets peuvent etre mises en evidence, aussi bien a l'echelle locale que regionale. Pour la prevision du bilan d'eau des forets, il est necessaire de prendre en compte les variations locales de consommation en eau et de conductance stomatique.

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

L'influence de contraintes internes elevees dans l'arbre, et du comportement mecanique transverse du bois, sur l'importance des fentes d'abattage, a ete etudiee chez 15 peupliers I214 (clone sensible au probleme) âges de 30 ans. Pour ces arbres le protocole suivant a ete adopte: i) Estimation des deformations residuelles en 4 points a la peripherie du tronc, a une hauteur de 1,30 m. La position du pic de deformation est generalement estimee par la direction d'inclinaison de l'arbre mesuree sur 6 m. ii) Quantification des fentes sur la section d'abattage et sur une section voisine des points de mesures des deformations: longueur et profondeur maximale estimee des fissures [...]

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.

The “plastid initial,” the presumed precursor of eoplasts and proplastids, is present in the cells of the apical meristem of winter buds of poplar (Populus euramericana). The formation of the plastid initial in the cells of winter buds is initiated soon after the breaking of the innate or resting stage of dormancy, even in winter under nongrowing conditions in mid-January or early February. From this stage to March, the conglomeration of the plastid initial and the formation of prolamellar bodies is evident. In contrast to the poplar samples kept outdoors, the cells of the apical meristem of the indoor winter buds did not show any indication of the formation of the plastid initial and the buds of the latter sample did not flush even at the end of May. These results suggest that the sequence of reactions involved in the onset of regrowth may be closely related to the formation of the plastid initial.

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.

International audience; Genotypic variability for productivity, wateruse efficiency and leaf traits in 33 genotypes selected from an F1 progeny of Populus deltoides Bartr. ex Marsh • Populus trichocarpa L. was explored under optimal and moderate water-deficit conditions. Saplings of the 33 genotypes were grown in a two-plot open field at INRA Orle´ ans (France) and coppiced every year. A moderate water deficit was induced during two successive years on one plot by withholding irrigation, while the second one remained irrigated (control). Stem biomass and leaf structure (e.g., specific leaf area and leaf area) were measured in 2004 and 2005 and functional leaf traits (e.g., carbon isotope discrimination, D) were measured only in 2004. Tolerance to water deficit was estimated at genotype level as the ability to limit losses in biomass production in water deficit versus control trees. Stem biomass, leaf structure and D displayed a significant genotypic variability whatever the irrigation regime. For all traits, genotype ranks remained stable across years for similar irrigation conditions. Carbon isotope discrimination scaled negatively with productivity and leaf nitrogen content in controls. The most productive genotypes were the least tolerant to moderate water deficit. No relationship was evidenced between D and the level of tolerance to water deficit. The relationships between traits evidenced in this collection of P. deltoides • P. trichocarpa F1 genotypes contrast with the ones that were previously detected in a collection of P. deltoides • Populus nigra L. cultivars tested in the same field trial.

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

Populus euramericana cv. I-214 andHelianthus annuus L. cv. Russian Mammoth were exposed to various concentrations of O3 SO2 or NO2 for 2 h in a cylindrical assimilation chamber. The threshold concentrations of air pollutants for inhibition of net photosynthesis differed between the two species and also between the pollutants tested. Furthermore, the lethal concentrations where the net photosynthetic rates were completely inhibited, also differed between species and between pollutants. For SO2 and NO2,P. euramericana was more tolerant photosynthetically thanH. annuus when related to the concentration of pollutants used during the experiment. However, when related to the cumulative uptake rate of each pollutant, the photosynthetic tolerance of the two species was similar. In contrast to the effects of SO2 or NO2, the influence of O3 on net photosynthesis was quite different. The relative rates of net photosynthesis in both species showed the same linear relationship with O3 concentration. However, the relationship between the relative rate of net photosynthesis and the cumulative uptake rate of O3 differed between the two species, although it was linear in both cases.

El objetivo del trabajo fue estudiar el efecto del sitio, el híbrido y el clon, sobre la altura total, DAP, volumen, densidad de la madera, longitud de fibras y rendimiento, de 11 clones de álamos. Se muestrearon ensayos de 10 años en dos sitios de Argentina (MD y EG). Los clones provienen de cruzamientos de P. deltoides, de cruzamientos de P. deltoides x P. nigra (P. x canadensis = P. euramericana) y P. deltoides. El sitio influyó significativamente en el crecimiento y densidad, el híbrido en la altura, densidad y longitud de fibras y los clones en todas las variables. Los árboles del sitio MD resultaron 5% más altos y 2% más densos, pero los ejemplares de EG resultaron con mayor DAP (7%) y volumen (11%). Los híbridos de P. x deltoides resultaron 4% mas altos y 4% más densos que los P. x canadensis. En longitud de fibras los híbridos P. x canadensis fueron 3% superiores. Las diferencias entre sitios y entre híbridos no resultaron tan marcadas considerando el conjunto de las propiedades. Los clones tuvieron diferente respuesta en las propiedades independientemente del cruzamiento del que derivan. Se destacaron los clones 610-31 y 564-17 (P. x deltoides) y 568-1 y Triplo (P. x canadensis)., The objective of this paper was to study site, hybrid cross and clone effects on total height, DBH, volume, wood basic density, fibre length and yield, of eleven poplars clones. 10-year-old hybrid poplar clones were sampled at two sites in Argentina (MD and EG). The material studied consisted of two poplar hybrid crosses Populus deltoides x P. deltoides and P. deltoides x P. nigra (P. x canadensis = P. x euramericana), as well as P. deltoides. Sites influenced significantly growth traits and wood density, hybrid influenced tree height, wood density and fibre length and clones influenced all variables. MD trees were 5% higher and 2% denser than EG trees, but EG trees were 7% greater in BDH and 11% more volume than the MD trees. P. deltoides and P. deltoides intra specific crosses were 4% higher and 4% denser than P. x canadensis trees. P. x canadensis fibre length was 3% higher than P. x deltoides. According to all properties, difference between site and hybrid were not very important. The properties of the clones had different responses regardless of the hybrid crosses. 610-31 and 564-17 clones (P. x deltoides) and 568-1 and Triplo (P. x canadensis) clones were distinguished., Facultad de Ciencias Agrarias y Forestales

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.

Este ensayo tuvo como objetivo determinar el material y la época de plantación más adecuada para la instalación en sitio definitivo de un cultivo de álamos con los clones Populus euramericana Conti 12 y Populus deltoides Harvard en las condiciones ambientales de la provincia de Mendoza. La plantación se realizó en dos épocas distintas: otoño y primavera, utilizando como material de plantación en ambos casos: a. barbados: plantas con raíz y brote de 1 año (R1T1); b. plantas recepadas: plantas con raíz de 1 año y brote del año cortado a 30 cm de nivel de suelo (R1T0); c. estacas: 1.5-2.5 cm de diámetro y 30-40 cm de longitud. Los resultados se expresaron en porcentaje de plantas prendidas y en volumen de madera producida por hectárea a los siete años en cada una de las variantes. Para los materiales y condiciones del ensayo el mejor resultado fue para el clon Conti 12 plantación en otoño utilizando barbados (plantas R1T1) o plantación en primavera utilizando estacas, barbados (R1T1) o plantas recepadas (R1T0). Para el clon Harvard, plantación en primavera utilizando planta recepada (R1T0) o estacas. This assay was made in order to determine material and planting season more adequate for the definitive installation of poplar forest under environmental conditions of Mendoza, using the following clones: Populus euromaericana Conti 12 and Populus deltoides Harvard. Planting was made in two different seasons: autumn an spring, using as planting material: a. plant with roots and bud of 1 year old (R1T1); b. plants with roots of 1 year old and bud cut at 30 cm of soil level (R1T0); c. cuttings: 1.5-2.5 cm of diameter and 30-40 cm of length. Results were expressed in percentage of prendidas plants and wood percentage by hectare at seven years. The best result was for Conti 12 planted in autumn, using 1 year old plants, or planted in spring using R1T1 plants, R1T0 plants or cuttings. The best result for Harvard clone was planting in spring using R1T0 plants or cuttings. Fil: Calderón, Alberto. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto Forestal Fil: Settepani, Valeria. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto Forestal Fil: Bustamante, Juan A.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto Forestal Fil: Riu, Nuria. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto Forestal

Accepted as original article in Journal of Wood Science (6th may 2004); The detachment of gelatinous layer (G-layer), often observed on microtome cross sections, leads some authors believe that G-layer cannot act as the driving force of longitudinal shrinkage in tension wood. The aim of this study was to observe the detachment of G-layer along fibres. Green wood block was cut transversely into two samples. One sample was kept in water and the other oven-dried. One face being common to both samples, detachment of G-layer has been studied on the same fibres. Observations have been performed after blocking deformation by embedding. It reveals that the detachment of G-layer is a cutting effect produced during the first making of the transverse face of the wood block to be embedded. After 100 µm far from this primary surface of the sample no detachment can be observed. Drying shrinkage does not affect or little this detachment. The result seems to explain well why the detachment of G-layer occurs during sectioning using a conventional sliding microtomy. These observations prove the adhesion of G-layer in massive wood and confirm the active role of G-layer in tension wood properties.

International audience; Dans cette deuxième partie, avec l'aide des analyses discriminantes, les clones de Peuplier testés, série par série, ont pu être attribués aux groupes de clones "ponts" constitués lors de la première typologie. Les résultats sont globalement très cohérents et conformes aux prévisions. D'un point de vue méthodologique, les deux informations principales sont qu'il faut au moins 4 sites par série d'essais pour bien appréhender la variabilité entre les sites, et qu'il manque un groupe de clones "ponts" peu performants dans tous les sites. La validité des résultats et les limites de la méthode sont ensuite discutées. Enfin, des moyens d'améliorer la méthode sont proposés. Ils concernent le nombre de sites à installer, la composition des groupes de clones "ponts", la densité de plantation à préconiser, et les observations qualitatives complémentaires qui sont permises dans ce type de tests.