Claudine Morvan

• Université de Rouen Normandie

Due to their particular tensile properties and composition, flax cellulosic fibres are widely used in various applications and are important in the stem architecture, as a source of mechanical support. Here, we have examined how various chemical extractions of cell-wall polysaccharides might improve our understanding of the structure and compositio...

Flax fibers (Linum usitatissimun L.) with good mechanical properties are required to reinforce polymers. This work provides an original method to determine the stiffness of dried or green fibers contained inside the plant. We studied three recent flax varieties (Marylin, Eden and TDL25) with distinct lodging resistances. After mechanical characteri...

The role of the main cell-wall polysaccharide-constituents of flax fibres on their mechanical behaviour has been investigated. One sample of scutched flax fibres underwent a successive sequence of extractions (boiling water, EDTA, HCl, NaOH), and tensile tests on elementary fibres were carried out after each step. Results indicated a role of the pr...

Flax fibres are widely used for composites reinforcement. Within the plant, these fibres have a mechanical support role for the stem, participating especially in the resistance against lodging. Flax stems (Linum usitatissimum) of the Marylin variety were cultivated in the same geographical zone over 4 successive years. Various parameters influencin...

Natural biocomposites were prepared from flax fibers and mucilage polysaccharides extracted from flax seeds, as a matrix, in two steps: impregnation and compression molding. The ribbons were preimpregnated with water plasticized mucilage. Solid mucilage (30%, w/w) was added to the ribbon impregnated with 20% mucilage, and the composite was compress...

L'hypocotyle de lin (Linum usitatissimum) peut présenter en quelques jours, selon son environnement, des métabolismes pectiques très différents, en particulier du point de vue de la densité de charges. Après 3 jours de germination à l'obscurité, la paroi est particulièrement riche en acides pectiques, qui lui sont liés covalentement. L'utilisation...

Upon hydration, flax seeds secrete mucilages whose content and physico-chemical properties vary according to the genotype and environment. The aim of the work was to investigate the complex genetic relationships between the vegetative period, colour, size and production of seed, the composition (polysaccharides and proteins) and physico-chemical pr...

The tensile properties of flax fibres might permit them to be used in composites as reinforcement in organic resin, as long as their mechanical properties are reproducible and their water sorption are reduced. In this study, to minimise the variability of mechanical properties, several samples of flax fibres were blended as a non-woven fabric. In o...

The present study aimed at analyzing the structural features of seed mucilage and cell-wall polysaccharides which accounted for 41% of the mass of flax meal (FM). A combination of high molar-mass mucilage-like polysaccharides (rhamnogalacturonan and arabinoxylan) was released from FM in water, together with arabinogalactan proteins and glucans. Abo...

An elementary plant fiber could be assimilated to a laminate, mainly constituted of the secondary wall S2 layer, made of a few non-crystalline polysaccharides reinforced by cellulose fibrils organized in a helix, with a microfibrillar angle (MFA) around 10° relative to the longitudinal fiber axis. This paper investigates the relationships between t...

New natural biocomposite materials were prepared from flax. Non-woven flax fibres material was chosen as a reinforcement and mucilage polysaccharides, extracted from flax seeds, were used as a matrix. Mucilages were extracted from two spring fibre-varieties, Aurore and Alizee. The matrix was crosslinked with epichlorohydrin (T = 70 °C, P = 50 bar,...

Capsule Skylarks and Yellowhammers generally did not preferentially establish territories in flax relative to autumn-sown crops on lowland farmland.Aims To investigate the biodiversity value of flax using farmland birds as indicator species.Methods Field surveys took place annually between 2009 and 2011 in Northern France, during the breeding seaso...

Water imbibition of flax seed induces secretion of mucilages whose physico-chemical properties vary according to genotype and environment. The viscosity and composition of mucilage have ecological implications and also affect the utility of the crop. Several types of enzymes are secreted along with the mucilage. Our objective was to study these enz...

The potential of mature flax plants (cv. Hermes) to tolerate and accumulate cadmium (Cd) was studied to determine which part of the plant would be the key organ for phytoremediation purposes. After 4month-growth on sand substrate containing 0.1mM Cd in a greenhouse, the roots and stems were separated and the stems were divided into three parts. The...

Plant fibers are one of the most important renewable resources, used as raw material in the paper industry, and for various textiles and for composites. Fibers are structural components in timber and an energy-rich component of fuel-wood. For the plant itself, fibers are important in establishing plant architecture, as a source of mechanical suppor...

Thermal stability and structural characteristics of air-dry and swollen crude flax, bleached flax and cotton fibres and the behaviour of bound water were analysed using thermogravimetry, microscopy, differential scanning calorimetry, low-temperature 1 H NMR spectroscopy and cryoporometry methods. Both air-dry and swollen fibres contain strongly (SB...

Structural (crystallinity), textural (pore volume, V p , specific surface area, S BET , pore size distribution, PSD) and adsorption characteristics of bleached flax fibres and cotton fibres have been determined using equilibrium adsorption of nitrogen, water, chlorhexidine diacetate (CHX) and methylene blue (MB), adsorption-desorption kinetics of M...

This study is focused on enzymatically upgrading the functional properties of flax fibres. Green flax fibres were treated with a polygalacturonase and a pectate lyase (PaL) and their properties were compared with dew-retted fibres. Morphological observations, vapour-sorption analyses and mechanical measurements showed that PaL-treatment was able no...

An enzyme/colloidal-gold complex was prepared using a purified endopolygalacturonase (endoPGH, E.C. 3.2.1.15). Gold particles with a radius of 4·8 nm were prepared. To stabilize the gold particles, it was necessary to add a minimal amount of enzyme (approximately 0·5 μg) at a pH higher than its isoelectric pH. Under these conditions, the number of...

Silane (Si) and styrene (S) treatments were applied on flax fibres in order to improve their adhesion with a polyester resin and to increase their moisture resistance. The water sorption and permeation kinetics of the composites were correlated with the water sorption behaviour of untreated and treated fibres. An increase of the water barrier effec...

The effect of 0.5mM cadmium (Cd) was studied on the ultrastructural aspects and pectin features of the walls of flax cellulosic fibres when the thickening of secondary wall had just started in the hypocotyl of 10-day old seedlings. As seen by PATAg staining in controls, cell-wall formation displayed two distinct steps, secretion and remodelling, wh...

During the first stage of flax growth, stem elongation reaches 2.4 cm per day and the percentage of cell wall remains quite constant (4–15%). Cellulosic fibres develop principally during capsule formation and seed maturation. During the latter stage, the proportion of walls increases from 15 to 60% and the elongation is diminished to 0.5 cm per day...

Plant fibers have several aspects, such as low energetic production costs, biodegradability and great mechanical properties, which make them very attractive in the field of composite reinforcement. The aim of this study was to compare the impact of two eco friendly water washings on the thermal behavior, surface morphology and mechanical properties...

Most flax (Linum usitatissimum) varieties are described as tolerant to high concentrations of Cd. The aim of the present paper was to better characterize this tolerance, by studying the responses of flax plantlets, cv Hermes, to 18d growth on 0.5mM Cd. In Cd-treated seedlings, the majority of Cd was compartmentalized in the roots. Analysis of other...

In flax hypocotyls, cadmium-induced reorientation of growth coincides with marked changes in homogalacturonan (HGA) epitopes that were recognized by JIM7 and JIM5 antibodies in the external tangential wall of the epidermis. In the present study, LM7 and 2F4 monoclonal antibodies were used, in addition to JIM5 and JIM7, to extend the investigation o...

In hypocotyls of flax (Linum usitatissimum) cadmium-induced reorientation of growth (i.e. an increase in expansion and a decrease in elongation) coincides with marked changes in the methylesterification and cross-linking of homogalacturonans within various cell-wall (CW) domains. The aim of the present study was to examine the involvement of pectin...

The mechanical properties of flax fibres are analysed as a function of their biochemical and morphological characteristics. The fibres, from the Agatha variety, have been selected from either the top, the middle or the bottom of the stems. The results of each analysis are discussed according to the position of the fibre in the stem and compared amo...

Des essais de nanoindentation ont été réalisés sur différentes fibres végétales. Dans un premier temps, nous avons mis en évidence leur anisotropie marquée en comparant les modules d'Young longitudinaux obtenus par des essais de traction sur fibres unitaires avec leurs modules transverses déterminés grâce à des essais de nanoindentation. La seconde...

In this work, in order to improve the adhesion between a polyester matrix (unsaturated polyester resin) and flax fibres (Linum usitatissimum L.) and to increase their moisture resistance, chemical surface treatments have been used. These different treatments were performed with maleic anhydride (MA), acetic anhydride (Ac), silane (Si) and styrene (...

Natural biocomposite materials were prepared consisting of a crosslinked natural matrix and natural fibres. Non-woven flax fibres material was chosen as a reinforcement and mucilage polysaccharides, extracted from linseeds, were used as a matrix. The matrix was crosslinked with glutaraldehyde and glycerol was added as plasticizer. The kinetic of th...

RÉSUMÉ. Les fibres de lin présentent de nombreux avantages pour le renforcement de matériaux composites. L’objectif de ce travail est de caractériser les fibres de lin oléagineux (variété Oliver) d’un point de vue de sa morphométrie, de ses propriétés mécaniques et de sa composition biochimique. Les propriétés mécaniques moyennes en traction sont i...

Thirteen pure lines from VIR flax genetic collection were evaluated for their vegetative period, production, quality of textile fibre, structure and composition of the fibre. Correlation analyses showed that strength of technical fibres was positively correlated with plant height, straw production and number of bundles per stem section and negative...

In this paper, we report that Erwinia carotovora can perform controlled biological pectinolysis of green flax fibre. The degradation of pectic substances is considered a key step during this process and is estimated by determining the cation exchange capacity (CEC). A CEC characteristic of a ‘good retting degree’, is reached after 20 h incubation,...

The tensile mechanical properties of flax fibres from the Hermès variety are estimated according to their diameter and their location in the stems. The large scattering of these properties is ascribed to the variation of the fibre size along its longitudinal axis, as revealed by SEM observations. The higher values of the mechanical properties for t...

This paper presents results from a study of fibres extracted from Zostera marina eel-grass collected from the Baltic coast. This species of sea-grass is shown to contain small diameter (around 5 mu m) fibres composed of similar to 57% cellulose, similar to 38% of non-cellulosic polysaccharides (mainly xylan) and similar to 5% of residual matter so-...

In the course of our studies on the putative role of pectins in the control of cell growth, we have investigated the effect of cadmium on their composition, remodelling and distribution within the epidermis and fibre tissues of flax hypocotyl (Linum usitatissimum L.). Cadmium-stressed seedlings showed a significant inhibition of growth whereas the...

Because of their good mechanical properties and low density, natural fibers are more and more considered as reinforcement in composite materials. To improve the adhesion between the polymer matrix and natural fibers and to reduce the water sorption, helium cold plasma and autoclave treatments have been performed on flax fibers. The effect of these...

From this brief review it appears that the interactions between calcium ions and cell walls play a key role in plant physiology. Calcium ions are involved in many mechnisms: for example, stabilization of cell wall structures, acidic growth, ion exchange properties, control of the activities of wall enzymes. All these properties originate from the t...

Water and Chelator-soluble polymers were independently isolated from the alcoholic-insoluble substance (AIS) of Mesembryanthenum crystallinum leaves. After precipitation in ethanol and ultrafiltration (40kD cut-off) of recovered solids dissolved in water, the yield relative of the so-call Lw and LCh polymers to the AIS dry matter was 2.5±0.2 and 7±...

Non-lignified fibre cells (named gelatinous fibres) are present in tension wood and the stems of fibre crops (such as flax and hemp). These cells develop a very thick S2 layer within the secondary cell wall, which is characterised by (1) cellulose microfibrils largely parallel to the longitudinal axis of the cell, and (2) a high proportion of galac...

Fibres in the middle part of the hypocotyl of young flax plantlets are organised in a circle of one hundred cells around the vascular cylinder. Apart from cellulose, their walls, of large thickness (2-5 μm), contain 30 to 50% of non-cellulosic polysaccharides (NCPs). NCPs consist mainly of β-(1-4)-galactan, together with rhamnogalacturonan of type...

Water-soluble polysaccharides were isolated from Mesembryanthemum crystallinum. Two methods were applied, based (i) on the extraction in hot water (for fresh and dry plants, FP and DP) and (ii) on freeze-thawing of fresh plants (FT). Each fraction was purified by precipitation in ethanol followed by ultrafiltration of recovered solids dissolved in...

In composite materials, fibers used as reinforcements are usually synthetic fibers such as glass. Since several years, for economic and environmental reasons, there has been an increasing interest in using plant fibers in composite systems. In this work, polyester composites reinforced by flax fibers submitted to helium cold plasma and/or autoclave...

The complex structure of flax fibres involves many chemical biomolecules located in an amorphous matrix in which cellulose micrifibrils are embbeded. The drying of flax fibres influences significantly their tensile strength. This result can be explained by the creation of damages within the fibre and by the modification of the chemical composition...

Pectic polysaccharides were obtained from chalkumra (Benincasa hispida) fruit by sequential extraction with ammonium oxalate (fraction BOX), dilute acid (fraction BHCl), and cold dilute alkali (fraction BOH). The highest yield of polysaccharides was obtained with oxalate and HCl. BOX was enriched in partly methyl-esterified galacturonic acid, where...

The objective of the review is to provide fundamental knowledge on the chemical composition and structural characteristics of flax fibres. These are long and multinucleate cells without septum or partition (average length 2–5 cm) and have a secondary wall of very large thickness (5–15 μm). Fibres are gathered in bundles of one to three dozen cells...

A cDNA of a flax (Linum usitatissimum) pectin methylesterase (PME) gene, Lupme3, was isolated by RACE-PCR. A partial sequence of this cDNA was inserted in antisense orientation downstream the cauliflower mosaic virus 35S promoter and introduced into the flax genome via Agrobacterium tumefaciens. Transgenic calli derived from the cocultivated explan...

The Lupme3 flax (Linum usitatissimum) gene encodes a putative pectin methylesterase (PME). A cDNA was generated by RACE-PCR using two consensus sequences to generate primers. PMEs are encoded by numerous genes (more than 60 ORFs in Arabidopsis contain PME consensus sequences) and little information is available on their expression regulation, and t...

Flax fibers have been the subject of many biochemical studies, which revealed that cellulose and pectins are the major constituents of their walls. In contrast, little is known about the location of these polymers within the walls of mature fibers by microscopic methods. This has been technically hampered by the very thick secondary wall of fibers,...

Flax fibers have been the subject of many biochemical studies which revealed, that cellulose and pectins are the major constituents of their walls. In contrast, little is known about the location of these polymers within the walls of mature fibers by microscopic methods. This has been technically hampered by the very thick secondary wall of fibers,...

The Arabidopsis thaliana sam1 gene encoding S-adenosylmethionine synthetase (EC 2.5.1.6) was transferred to flax (Linum usitatissimum) cells via Agrobacterium tumefaciens. This enzyme catalyses the conversion of methionine to S-adenosylmethionine (SAM), the major methyl group donor in living cells. The aim of this work was to study the consequences...

Three pectin methyltransferases (PMT5, PMT7, PMT18; EC 2.1.1.6.x) were solubilized from the endo-membrane complex of flax cells, with 0.05% Triton X-100. After a 3 step-chromatography procedure, PMT7 and PMT5 were purified to apparent homogeneity. PMT5 and PMT7 differed regarding their optimum pH (5 or 7), the methyl acceptor (low or highly methyle...

Well-characterized pectin samples with a wide range of degrees of esterification (39-74%) were incubated with the solubilized pure alpha and gamma isoforms of pectinmethylesterase, from mung bean hypocotyl (Vigna radiata). Enzyme activity was determined at regular intervals along the deesterification pathway at pH 5.6 and pH 7.6. It has been demons...

Galactosyltransferases (GalTs), capable of transferring a galactosyl residue from UDP-galactose (UDP-Gal) to polysaccharide acceptor, were solubilized from flax (Linum usitatissimum L.) membranes using 0.5% CHAPS. The observed requirement for a rhamnogalacturonan I (RG-I) exogenous substrate to stimulate the solubilized GalT activity provided the f...

The deposition and formation of a thick secondary wall is a major event in the differentiation of flax (Linum usitatissimum) fibers. This wall is cellulose-rich; but it also contains significant amounts of other matrix polymers which are noncellulosic such as pectins. We have used immunocytochemical techniques with antibodies specific for various e...

Four proteins were isolated from depectinised elementary fibres of flax (Linum usitatissimum L.), using either alkali or cellulase digestion treatments. All the four proteins were characterized by a deficiency or low contents of hydroxyproline and by high levels of glutamic acid/glutamine and/or aspartic acid/asparagine. The two proteoglycans solub...

The development of pectin structural features during the differentiation of cambial derivatives was investigated in aspen (Populus tremula L. × P. tremuloides Michx.) using biochemical and immunocytochemical methods. Comparisons were also made between active and resting tissues. Active tissues, in particular cambial cells and phloem derivatives, we...

Well characterized pectin samples were incubated with cell wall-bound and -solubilized pure isoforms of pectinmethylesterase from mung bean hypocotyls (Vigna radiata). Both enzyme activity and average product structure were determined at intervals along the deesterification pathway at pH 5.6 and 7.6. The latter analyses were performed by 13C NMR sp...

Pectin methylesterases (PMEs, EC 3.1.1.11) catalyse the deesterification of pectins. Up to now, most information concerning their location was obtained from biochemical analyses. Taking advantage of specific anti-PME antibodies, we report the precise localization of PMEs at the electron microscopy level within the different cortical tissues of flax...

A protocol for partial thermally-induced depolymerization of differently methoxylated pectin samples is described. The resulting macromolecules have been fully characterized with various complementary techniques, such as size exclusion chromatography (SEC), potentiometry, viscometry and 13C NMR. Optimum conditions afford samples at 50–80% yield wit...

The proton spin-spin relaxation time, T2, measured from solid-state NMR, indicates a greater rigidity for cellulose than for the adhesive matrix between the microfibrils of flax ultimate fibres. Cytochemical and biochemical analyses allow the identification of: (1) EDTA-soluble RG I-polymers in the primary walls and cell junctions of fibres; (2) lo...

Traditionnellement, les fibres de lin sont mises à nu en laissant la nature opérer sur les pailles et allées au sol. Chercheurs et industriels explorent maintenant de nouveaux procédés enzymatiques d'extraction afin d'obtenir des fibres de meilleure qualité.

The activity of pectin methyltransferases (PMT) from endomembranes of flax cells (Linum usitatissimum L.) was enhanced in the presence of exogenous pectins. The value of optimal pH increased from 5.5 to 7.0 with the degree of methylesterification (DE from 0.00 to 0.50) of pectins. We showed, using size exclusion chromatography, that methylesterific...

We have investigated pectin methylesterase (PME) activity in flax seedlings (Linum usitatissimum L.) grown either in the dark or in the light. The activity was maximal in hypocotyls at the end of the growth, especially in the dark (2 to 3 nkatal per organ), and about 5500 nkatal per g of dry cell walls of 3-day-old hypocotyls. When calculated relat...

The methyltransferase activity (EC 2.1.1) of proteins solubilized with Triton X-100 from an endomembrane extract of flax (Linum usitatissimum L) has been assayed, using exogenous rhamnogalacturonan (RG) substrates: (a) a RG-I solubilized with EDTA-Na2 from mechanically-isolated flax fibres and (b) RG-II samples isolated from red wine. The transfer...

This paper deals with the enzymes controlling the extent and pattern of methylesterification in pectins within the primary walls of plant cells. It also reviews the consequences of methyl-esterification for gel formation within the cell wall and for the resistance of the wall to mechanical stress. Methyl ester groups are added to pectic galacturona...

Pectin methyltransferases solubilized from endomembranes of flax cells (Linum usitatissimun) (E.C. 2.1.1.1.18) consisted of several polypeptides, the molecular relative mass of which varied from very low (Mr≤5000) to very high (Mr ca 200,000) values. Several isoforms were detected from acidic to very basic pH with two main forms, 1) a basic form (p...

Abstract Flax cells (Liniiin usitatissiinmn L.), derived from hypocotyls, were cultured under white light or in the dark. In the light, cells produced less mass of fresh material but as much dry cell-wall as in the dark. Consequently, in the former condition, the yield of cell-wall strongly increased at the beginning of the exponential phase. Total...

Pectin methyltransferase complex was easily solubilized from the endomembranes of flax cells (Linum usitatissimum L.), when using Triton X- 100 detergent. The apparent K(M) for the methyl donor S- adenosylmethionine (SAM) was about 0.5 μM, when using polygalacturonic acid as an exogenous methyl-acceptor. In the presence of saturating concentration...

Polymers extracted with CDTA-Na2 (trans-diaminocyclohexane-á-tetra-acetic acid partially neutralized with NaOH) after a boiling water treatment from cell walls of 3-day-old seedlings of flax, germinated on water and in darkness, contained three main components: (1) rhamnogalacturonan I (RG-I)-like polymers with ratios of rhamnose to galacturonic ac...

Successive extraction of mechanically-isolated flax fibres with ethylene-diaminetetraacetic acid partially neutralized with NAOH EDTA-Na2 and NaOH solubilized about 25% of the mass of fibres. The cation exchange capacity (CEC) of the fibres decreased from 0.100 ± 0.025 meq g−1 to 0.035 ± 0.015 meq g−1 after EDTA-Na2 extraction and then was reduced...

In flax (Linum usitatissimum, c.v. Ariane) pectin methylesterase (PME) (EC 3.1.1.11), ionically bound to cell-wall, was composed mainly of forms with isoelectric points (pIs) of 7.1, 7.6 and 9.6. Minor forms, with acid pIs (4.5, 4.8 and 6.3), were detected during the purification of two of these forms. Polyclonal antibodies were raised against the...

Polymers extracted with CDTA-Na2 (trans-diaminocyclohexane-á-tetra-acetic acid partially neutralized with NaOH) after a boiling water treatment from cell walls of 3-day-old seedlings of flax, germinated on water and in darkness, contained three main components: (1) rhamnogalacturonan I (RG-I)-like polymers with ratios of rhamnose to galacturonic ac...

Physicochemical and enzymic approaches were used to characterize highly methylated pectins isolated from mung bean hypocotyl cell walls. Young cell walls were particularly rich in rhamnogalacturonan-1-like polysaccharides, the galacturonic units of which might be fully methylated. Short, smooth, homogalacturonan blocks separated these hairy regions...

Treatment of suspension-cultured flax cells with the ionophore monensin increased glucan synthase II activity, a plasmalemma endomembrane complex, but reduced the activity of inosine-5 '-diphosphatase, a Golgi marker. Activities of glucan synthase I and galactan synthases, endomembrane enzymes that are localized in Golgi apparatus and implicated in...

The characteristic features of the pectins present in the walls of immature fibre cells of the hypocotyl of flax seedlings have been studied by a combination of three subtractive methods (treatment with boiling water, calcium chelator, and free endopolygalacturonase), three staining reactions (periodic acid-thiocarbohydrazide-silver, Ruthenium Red,...