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International audience; The essential oils (EOs) of leaves, flowers and stems of Achillea santolina L. (Asteraceae) collected at complete flowering stage from Southwest of Algeria, were isolated by hydrodistillation and subsequently analyzed by means of GC and GC/MS. Quantitative and qualitative differences in chemical compositions between the studied parts of this plant were observed. The EOs were rich in oxygenated monoterpenes (65.91–79.94%). The major constituents in the flowers, leaves and stems were: camphor (68.12, 65.17, 55.72%), 1,8-cineole (8.22, 4.77, 0.7%) and α-terpineol (2.84, 5.35, 2.76%). The highest EO yields were obtained for the leaves and the flowers (0.59 and 0.49% “v/w”, respectively), whereas, the stems were characterized by very weak yield value (0.05%).

International audience; In constrast with Nêlêmwa (Oceanic, New Caledonia) whose lexemes are most generally subcategorised as nouns or verbs and undergo category-changing derivations, in Amis (Formosan), roots are pervasively categorially neutral, yet they contain semantic features and instructions that allow or disallow combination with primary derivational affixes which specify their class and category. Lexical categories are expressed after derivation from roots to become morphosyntactic words projected in a syntactic frame; they are then quite rigidly subcategorised as verbal, nominal or adjectival-modifying heads. Still, word forms display some functional flexibility; for instance, nouns and derived nouns, pronouns, numerals may be predicative in equative, ascriptive and focus constructions, simply by being in the syntactic position of the verb. Such functional flexibility is asymmetrical and does not apply to derived verb stems which must be nominalised to achieve argument function.

Terrestrial laser scanning (TLS) technology is a powerful tool for assessing tree growth based on time series analysis, as it allows a level of scrutiny not achievable using established destructive techniques.[br/] We applied TLS technology to 21 wild cherry trees grown in a research plot near Breisach (southern Germany) in order to build quantitative structure models (QSMs) for each tree. Scans were carried out over three subsequent years (2012-2014), so that three QSMs per each tree were constructed.[br/] Using the above approach, we were able to assess the annual growth of the individual wild cherry trees in terms of diameter and height, stem and branch volume, and the merchantable timber fraction. In addition, the growth of single branches of sample trees was detected and quantified. The availability of QSMs based on TLS-derived data allowed the accurate determination of crown length and width, as well as the volume reduction as the result of the tree pruning applied after the first scan (2012). The aboveground biomass (AGB) was assessed for each tree based on the QSM-derived volume and published wood density values for wild cherry, and then compared with AGB values estimated with standard allometric methods, obtaining a very high correlation (r(adj)(2) = 0.941).[br/] We concluded that the proposed approach is an effective non-destructive technique to accurately assess the increase of tree biomass, and discuss its future application in the forestry sector.

Existing models for describing knot morphology are typically based on polynomial functions with parameters that are often not biologically interpretable. Hence, they are difficult to integrate into tree growth simulators due to the limited possibilities for linking knot shape to external branch and tree characteristics. X-ray computed tomography (CT) images taken along the stems of 16 jack pine (Pinus banksiana Lamb.) trees and 32 black spruce (Picea mariana (Mill.) B.S.P.) trees were used to extract the three-dimensional shape of 3450 and 11 276 knots from each species, respectively. Using a nonlinear approach, we firstly fitted a model of knot geometry adapted from a Weibull function. Separate equations were used to describe both the curvature and the diameter of the knot along its pith. Combining these two equations gave an accurate representation of knot shape using only five parameters. Secondly, to facilitate the integration of the resulting model into a tree growth simulator, we extracted the parameters obtained for each knot and modelled them as functions of external branch and tree characteristics (e.g., branch diameter, insertion angle, position in the stem, tree height, and stem diameter). When fitted to a separate data set, the model residuals of the black spruce knot curvature equation were less than 2.9 mm in any part of the knot profile for 75% of the observations. The corresponding value from the diameter equation was 2.8 mm. In jack pine, these statistics increased to 5.4 mm and 3.2 mm, respectively. Overall, the ability to predict knot attributes from external tree- and branch-level variables has the potential to improve the simulation of internal stem properties.

Document Type : Proceedings Paper Conference Date : SEP 20-24, 2010 Conference Location : Rabat, MOROCCO Conference Host : Min Sch Rabat; Coupling different techniques in spectroscopy is an efficient approach to characterise complex biological material. This work is carried out to characterise maize stem cell wall composition in the context of biofuel production. In this research, we propose to couple infrared, fluorescence and Raman hyperspectral images. Investigations have been attempted in coupling spectral data by means of multiblock methods. Multiblock techniques have been assumed to be equally applicable and effective in the analysis of biological samples with complex chemical composition and structure. The most commonly used methods are based on sequential approaches. In this article, we propose 1) to condition the data to be analysed towards multiblock analysis in term of pre-processing and organising the blocks from the initial hyperspectral images, 2) to apply Multiple Co-inertia Analysis (MCoA) a symmetrical method providing orthogonal loadings for spectral interpretation and score images for spatial analysis, and 3) to interpret and to analyse in one hand the common structure revealed by the three modalities and in the other hand the independent contribution to explain the variability under each block. (C) 2012 Elsevier B.V. All rights reserved.

International audience; Introduction The use of terrestrial LiDAR (light detection and ranging) scanners in forest environments is being studied extensively at present due to the high potential of this technology to acquire three-dimensional data on standing trees rapidly and accurately. This article aims to establish the state-of-the-art in this emerging area. Objectives Terrestrial LiDAR has been applied to forest inventory measurements (plot cartography, species recognition, diameter at breast height, tree height, stem density, basal area and plot-level wood volume estimates) and canopy characterisation (virtual projections, gap fraction and three-dimensional foliage distribution). These techniques have been extended to stand value and wood quality assessment. Terrestrial LiDAR also provides new support for ecological applications such as the assessment of the physical properties of leaves, transpiration processes and microhabitat diversity. Results Since 2003, both the capabilities of the devices and data processing technology have improved significantly, with encouraging results. Nevertheless, measurement patterns and device specifications must be selected carefully according to the objectives of the study. Moreover, automated and reliable programmes are still required to process data to make these methodologies applicable specifically to the forest sciences and to fill the gap between time-consuming manual methods and wide-scale remote sensing such as airborne LiDAR scanning.

In this study, eight maize recombinant inbred lines were selected to assess both the impact of lignin structure and the impact of cell wall reticulation by p-hydroxycinnamic acids on cell wall degradability independently of the main "lignin content" factor. These recombinant lines and their parents were analyzed for in vitro degradability, cell wall residue content, esterified and etherified p-hydroxycinnamic acid content, and lignin content and structure. Lignin structure and esterified p-coumaric acid content showed significantly high correlation with in vitro degradability (r = -0.82 and r = -0.72, respectively). A multiple regression analysis showed that more than 80% of cell wall degradability variations within these 10 lines (eight recombinant inbred lines and their two parents) were explained by a regression model including two main explanatory factors: lignin content and estimated proportion of syringyl lignin units esterified by p-coumaric acid. This study revealed new biochemical parameters of interest to improve cell wall degradability and promote lignocellulose valorization.

Defectiveness as suppletion of gaps

We analysed crown dynamics at the stand level in three plots of an even-aged sessile oak stand (one unthinned reference plot and two plots of different thinning intensities) of a long-term experiment in Rhineland Palatinate, Germany. Crown projections and stem locations were recorded in 1977, 1994 and 2004. Spatial structures of stems and crowns were analysed using the index of Clark and Evans and Ripley’s K-function. In the unthinned plot, despite crowns being highly asymmetric, it was shown that crowns did not expand in a way that makes their distribution more regular. In this dense plot with slender trees, the stability constraint was probably more important than the search for light. In the thinned plots, spatial distributions of both stems and crowns were found to be regular, in general with more regular distributions for crowns than for stems. The more regular spatial distributions of crowns were attributed to the effect of thinning and to the subsequent plastic reaction of the crowns of the remaining trees. The plastic reaction of crowns toward more regular distributions was stronger in the case of moderate thinning than in the case of intensive thinning. In the latter case, the lower plot density was probably less limiting for the access to light. Finally, the benefit of the plasticity of crowns in the thinned plots was quantified in terms of canopy cover at the stand level. Crown plasticity enabled a higher space occupation by the canopy and a reduction of overlaps between neighbouring crowns. The results of this study suggested that trees of a stand can adapt to their environment in order to find a trade-off between different functions like mechanical stability, access to light and the physiological cost associated with adaptive growth.

The internal conductance to CO(2) transfer from intercellular spaces to chloroplasts poses a major limitation to photosynthesis, but few studies have investigated its temperature response. The aim of this study was to determine the temperature response of photosynthesis and internal conductance between 10 degrees C and 35 degrees C in seedlings of a deciduous forest tree species, Quercus canariensis. Internal conductance was estimated via simultaneous measurements of gas exchange and chlorophyll fluorescence ("variable J method"). Two of the required parameters, the intercellular photocompensation point (C(i)*) and rate of mitochondrial respiration in the light (R(d)), were estimated by the Laisk method. These were used to calculate the chloroplastic photocompensation point (Gamma*) in a simultaneous equation with g(i). An independent estimate of internal conductance was obtained by a novel curve-fitting method based on the curvature of the initial Rubisco-limited portion of an A/C(i) curve. The temperature responses of the rate of Rubisco carboxylation (V(cmax)) and the RuBP limited rate of electron transport (J(max)) were determined from chloroplastic CO(2) concentrations. The rate of net photosynthesis peaked at 24 degrees C. C(i)* was similar to reports for other species with a C(i)* of 39 micromol mol(-1) at 25 degrees C and an activation energy of 34 kJ mol(-1). Gamma* was very similar to the published temperature response for Spinacia oleracea from 20 degrees C to 35 degrees C, but was slightly greater at 10 degrees C and 15 degrees C. J(max) peaked at 30 degrees C, whereas V(cmax) did not reach a maximum between 10 degrees C and 35 degrees C. Activation energies were 49 kJ mol(-1) for V(cmax) and 100 kJ mol(-1) for J(max). Both methods showed that internal conductance doubled from 10 degrees C to 20 degrees C, and then was nearly temperature-independent from 20 degrees C to 35 degrees C. Hence, the temperature response of internal conductance could not be fitted to an Arrhenius function. The best fit to estimated g(i) was obtained with a three-parameter log normal function (R(2)=0.98), with a maximum g(i) of 0.19 mol m(-2) s(-1) at 29 degrees C.

International audience; An ecophysiological growth process model, called INCA, for simulating the growth and development of a young walnut tree (Juglans regia L.) during three or four years, is presented. This tool, currently under development, aims at integrating architectural and physiological knowledge of the processes involved, in order to give a more rational understanding of the pruning operation. The model describes a simple three-dimensional representation of tree crown, solar radiation interception, photosynthesis, respiration, growth and partitioning of assimilates to leaves, stems, branches and roots. It supports the hypothesis that the tree grows as a collection of semiautonomous, interacting organs that compete for resources, based on daily sink strengths and proximity to sources. The actual growth rate of organs is not predetermined by empirical data, but reflects the pattern of available resources. The major driving variables are solar radiation, temperature, topological, geometrical and physiological factors. Outputs are hourly and daily photosynthate production and respiration, daily dimensional growth, starch sorage, biomass production and total number of different types of organ. The user can interact or override any or all of the input variables to examine the effects of such changes on photosynthate production and growth. Within INCA, the tree entities and the surrounding environment are structured in a frame-based representation whereas the processes are coded in a rule-based language. The simulation mechanism is primarilybased on the rule chaining capabilities of an inference engine.; L'article présente un modèle écophysiologique de croissance et développement du noyer. INCA vise à intégrer les connaissances architecturales et physiologiques que l'on a sur le sujet, de manière à optimiser les opérations de taille.

International audience; A method for the measurement of the three-dimensional (3D) architecture of trees was applied to describe two 2O-year-old walnut trees, one of them is a timber tree while the other is a fruit tree. The method works at the shoot level and simultaneously describes the plant topology, the plant geometry and the shoot morphology. The method uses a 3D digitiser (3SPACE@ FASTRAK@, Polhemus Inc.) associated with software DiplAmi designed for digitiser control and data acquisition management. Plant images may be reconstructed from the data set by using the ray tracing software FOV-Ray. Visual comparison between photographs of the walnut trees and images synthesised from digitising was satisfactory. Distribution of basal shoot diameter, as well as leaf area and fruit distributions for both the timber and the fruit tree were non-uniformly distributed in the crown volume. Gradients were likely to be related to the light distribution within the tree. This is in agreement with previous experimental results on several tree species, and also with the predictions of tree architecture models based on light-vegetation interactions.