Jean-paul Charpentier - Academia.edu (original) (raw)

Papers by Jean-paul Charpentier

Cambium is a special meristem controlling both wood formation through xylogenesis processes and r... more Cambium is a special meristem controlling both wood formation through xylogenesis processes and radial growth of the stem. Whereas this type of meristem was well-described by histology in many trees, new investigations require to be developed at biochemical and molecular levels in order to know the key endogenous factors involved in cell division and differentiation. Cambial activation/reactivation is reported to be hormonally controlled (auxin, cytokinin) by growing peripheric organs (buds, leaves, roots) (Aloni, 1995; Savage, 1996). It is also reported that a local IAA gradient exists in the cambial zone and that it controls cell division and differentiation (Uggla et al., 1996). The first objective is to find molecular and biochemical markers (genes, proteins, auxins, phenolics) closely related to cambial activity and xylem differentiation. The role of these potential markers will be studied by means of methods of quantification, histolocalisation and genetic transformation appli...

Trees, 1998

Natural wood colouring process in Juglans sp. (J. nigra, J. regia and hybrid J. nigra 23´J. regia... more Natural wood colouring process in Juglans sp. (J. nigra, J. regia and hybrid J. nigra 23´J. regia) depends on native phenolic compounds accumulated in the transition zone between sapwood and heartwood AbstractmRadial distribution of soluble phenolics was investigated at different heights in stems of Juglans nigra, J. regia and hybrids J. nigra 23´J. regia. Four major phenolic compounds were studied: hydrojuglone glucoside (HJG), quercitrin (QUER) and two unknown compounds characterized as two ellagic acid derivatives E1 and E2. HJG and E1 content increased gradually in the sapwood, peaked in the sapwood-heartwood transition zone, and decreased drastically in the heartwood. QUER was accumulated preferentially around the transition zone, and its content was relatively low in the outer part of the sapwood and in the inner part of the heartwood. E2 content was low in the sapwood and increased in the heartwood. The heartwood formation was marked by the accumulation of new soluble compounds. The relationship between wood extractives and wood colour were evaluated and discussed. HJG was considered to be a major precursor of heartwood colour providing chromophores through hydrolysis (deglucosylation), oxidation and polymerization processes.

Planta, 2000

In walnut (Juglans regia L.), an otherwise dicult-to-root species, explants of cotyledons have be... more In walnut (Juglans regia L.), an otherwise dicult-to-root species, explants of cotyledons have been shown to generate complete roots in the absence of exogenous growth regulators. In the present study, this process of root formation was shown to follow a pattern of adventitious, rather than primary or lateral, ontogeny: (i) the arrangement of vascular bundles in the region of root formation was of the petiole type; (ii) a typical root primordium was formed at the side of the procambium within a meristematic ring of actively dividing cells located around each vascular bundle; (iii) the developing root apical meristem was connected in a lateral way with the vascular bundle of the petiole. This adventitious root formation occurred in three main stages of cell division, primordium formation and organization of apical meristem. These stages were characterized by expression of LATERAL ROOT PRI-MORDIUM-1 and CHALCONE SYNTHASE genes, which were found to be sequentially expressed during the formation of the primordium. Activation of genes related to root cell dierentiation started at the early stage of primordium formation prior to organization of the root apical meristem. The systematic development of adventitious root primordia at a precise site gave indications on the positional and biochemical cues that are necessary for adventitious root formation.

Industrial Crops and Products, 2011

The relationships existing among the values obtained when extracting the wood of four Argentinean... more The relationships existing among the values obtained when extracting the wood of four Argentinean species of Prosopis (P. alba, P. kuntzei, P. nigra, and P. ruscifolia) and one of the Acacia (A. aroma) by several procedures were evaluated and discussed. The used methods were: extraction in toluene/ethanol and hot water; determination of tannic and non-tannic content; measurement of phenolic compounds. Additionally, liquid chromatography (HPLC) was also used in order to quantitatively evaluate the content of (−)-mesquitol, a relatively unusual flavonoid (flavanol type). The total amount of Oxidation Products was also measured. They result from oxidation and polymerization processes of phenolic compounds occurring during heartwood formation, and were not separated during chromatographic analysis. Data evidenced a linear trend (R 2 = 0.970) between organic and tannic extractives of all species, and a similar one (R 2 = 0.927) between total phenols and tannic (or organic) extractives in the case of heartwood of Prosopis species. Interestingly, for sapwood very different values of organic extracts, tannic content or Oxidation Products type compounds were measured in spite of a similar amount of phenolic substances. Moreover, the various species presented the same peaks in chromatograms, thus evidencing the chemical similarity of compounds but a different quantity between heartwood and sapwood and also among the various species. The observed similarity implied that the various methods of extraction did not really extract only a single class of substances, and that great care must be adopted when using some specific procedures for extractions. Furthermore, the existing relationships between extractives and selected technological properties, namely specific volumetric shrinkage coefficient (BSvol) and natural durability (evaluated in terms of mass loss after fungal attacks in laboratory conditions), were given. It appeared that in heartwood BSvol was well correlated to organic extractives (R 2 = 0.984), thus evidencing the microimpregnation of cell walls by extractives, but the fitting quality of the correlation was dependent on the type of extractives used. Analogously, a good relationship between mass loss and phenolic compounds existed (R 2 = 0.764), and in this case the value of R 2 was even more dependent on the considered extracts. Moreover, the availability of quantitative data on several Prosopis species allowed to consistently evaluate the bioactivity of (−)mesquitol on the resistance against fungal attack, and the logarithmic form of the relationship between mass loss and (−)-mesquitol content suggested a direct fungicidal activity of this compound. On the other hand, data also evidenced that neither phenolic compounds nor (−)-mesquitol can be considered as the unique and definite factor able to determine the durability of the considered species.

Holzforschung, 2000

The effects of steaming were studied on Walnut wood from a hybrid (Juglans nigra 23 x J. regia) t... more The effects of steaming were studied on Walnut wood from a hybrid (Juglans nigra 23 x J. regia) tree in terms of wood colour and phenolic composition. Wood samples were subjected to treatments at 75. 100 and 125°C for 4, 8, 16 and 24 hours. Colour changes were ...

Functional Plant Biology, 2002

... Plant Biol., 2002, 29, 6371 Cuttings of the non-rooting rac tobacco mutant overaccumulate ph... more ... Plant Biol., 2002, 29, 6371 Cuttings of the non-rooting rac tobacco mutant overaccumulate phenolic compounds Odile Faivre-RampantA, Jean-Paul CharpentierB, Claire KeversA, Jacques DommesAD, HarryVan OnckelenC, Christian Jay-AllemandB and Thomas GasparA ...

BMC Genomics, 2011

Background: Eucalyptus is an important genus in industrial plantations throughout the world and i... more Background: Eucalyptus is an important genus in industrial plantations throughout the world and is grown for use as timber, pulp, paper and charcoal. Several breeding programmes have been launched worldwide to concomitantly improve growth performance and wood properties (WPs). In this study, an interspecific cross between Eucalyptus urophylla and E. grandis was used to identify major genomic regions (Quantitative Trait Loci, QTL) controlling the variability of WPs. Results: Linkage maps were generated for both parent species. A total of 117 QTLs were detected for a series of wood and end-use related traits, including chemical, technological, physical, mechanical and anatomical properties. The QTLs were mainly clustered into five linkage groups. In terms of distribution of QTL effects, our result agrees with the typical L-shape reported in most QTL studies, i.e. most WP QTLs had limited effects and only a few (13) had major effects (phenotypic variance explained > 15%). The co-locations of QTLs for different WPs as well as QTLs and candidate genes are discussed in terms of phenotypic correlations between traits, and of the function of the candidate genes. The major wood property QTL harbours a gene encoding a Cinnamoyl CoA reductase (CCR), a structural enzyme of the monolignol-specific biosynthesis pathway.

Biodegradation, 2010

The natural durability of four Argentinean species of Prosopis and one of Acacia was evaluated in... more The natural durability of four Argentinean species of Prosopis and one of Acacia was evaluated in laboratory tests, according to European standards, using three brown rot and one white rot fungi. These tests were complemented by assessing the wood chemical composition. All the species were from moderately slightly durable to very durable (classes 4-1), and in all cases the heartwood was the most resistant to fungal attack. Chemical extractives content (organic, aqueous, tannic and phenolic) was higher in the heartwood. However, species durability was not related to extractive contents nor with wood density. Instead, it is possible that extractives could contribute to natural durability in different ways, including the effects related to the antioxidant properties of some of them.

Annals of Forest Science, 2011

mainly quinone derivatives, were formed from nonstructural carbohydrates which were weakly correl... more mainly quinone derivatives, were formed from nonstructural carbohydrates which were weakly correlated to natural durability.

Annals of Forest Science, 2008

Methods based on near infrared spectroscopy used to assess wood properties are susceptible to var... more Methods based on near infrared spectroscopy used to assess wood properties are susceptible to variations in physical parameters (temperature, grain size, etc.). As wood is a hygroscopically sensitive material, we studied the effects of moisture on near infrared absorbance and calibration to accurately determine the application potential of this technique under routine.

Acta Botanica Gallica, 1996

Resume.-Afin d'etudier I' implication des flavono'ides dans Ia rhizogenese chez le noyer, Ia stra... more Resume.-Afin d'etudier I' implication des flavono'ides dans Ia rhizogenese chez le noyer, Ia strategie antisens chalcone synthase (CHS) a ete developpee pour en moduler le contenu tissulaire. Une sequence de 400 pb d'un gene CHS de noyer a ete introduite en orientation antisens dans des embryons somatiques via Agrobacterium tumefaciens. Par embryogenese secondaire, culture in vitro des axes embryonnaires et micropropagation, 13 souches transformees ant ete obtenues sous Ia forme de pousses feuillees. Six d'entre elles sous-expriment nettementles genes CHS et n'accumulent pas ou peu de flavono'ides. Ces explants torment de Ires gros cals a leur base et presentent des necroses apicales apres Ia phase d'induction. Les premiers tests d'enracinement semblent indiquer qu'une forte reduction de Ia teneur en flavono'ides endogenes s'accompagne d'une augmentation des taux d'enracinement.

Wood Science and Technology, 2012

Wood density is defined as the ratio of mass to volume and therefore in principle it should be po... more Wood density is defined as the ratio of mass to volume and therefore in principle it should be possible to calculate a unique partial least squares regression (PLS-R) model for several species. PLS-R models for wood density based on X-ray microdensity data were calculated for each species Pinus pinaster and Larix 9 eurolepis and for both species together. After cross-validation and test set validation the data sets were combined and final models were calculated. The common model gave a residual prediction deviation (RPD) of 3.1, a range error ratio (RER) of 11.7, and a SEP/SEC of 1.06. The single models for Pinus pinaster and Larix 9 eurolepis gave RPD's of 3.5 and 3.2, RER's of 13 and 11, and a SEP/SEC of 1.2. To the best knowledge of the authors all obtained PLS-R models are the first ones that fulfil the requirements according to AACC Method 39-00 (AACC in AACC Method, 39-00:15, 1999) to be used at least for screening (RPD C 2.5). Although this method and the defined limits were developed for the analysis of grains they can be used as a rough rule of thumb until limits for wood are available. The improvement of the PLS-R models, compared to published results, might be due to three facts (1) the higher number of scans collected for a single spectrum, (2) that the samples were better represented by the NIR spectra and X-ray microdensity values, and (3) that the sites for the measurement of NIR spectra and X-ray microdensity were coincided as strictly as possibly.