Building flax fibres: more than one brick in the walls

• Published in: Plant Physiology and Biochemistry Vol. 41; no. 11; pp. 935 - 944
• Main Authors: Morvan, Claudine, Andème-Onzighi, Christine, Girault, Raynald, Himmelsbach, David S., Driouich, Azeddine, Akin, Danny E.
• Format: Book Review Journal Article
• Language: English
• Published: Paris Elsevier Masson SAS 01-11-2003; Elsevier
• Subjects: Agronomy. Soil science and plant productions; Arabinogalactan-protein; Biological and medical sciences; Cell differentiation; Cell physiology; CELL WALLS; CELLULOSE; Cellulosic fibre; CELULOSA; CHEMICAL COMPOSITION; CHEMICOPHYSICAL PROPERTIES; COMPOSICIÓN QUIMICA; COMPOSITION CHIMIQUE; Economic plant physiology; FIBRAS; FIBRE; FIBRES; FLAX; Fundamental and applied biological sciences. Psychology; Galactan; GALACTANE; GALACTANOS; GALACTANS; GLICINA; Glucan; GLUCANE; GLUCANOS; GLUCANS; GLYCINE (ACIDE AMINÉ); GLYCINE (AMINO ACID); Glycine-rich protein; Growth and development; LIN; LINO; LINUM USITATISSIMUM; Morphogenesis, differentiation, rhizogenesis, tuberization. Senescence; PARED CELULAR; PAROI CELLULAIRE; Plant physiology and development; PLANTAS; PLANTE; PLANTS; PROPIEDADES FISICOQUÍMICAS; PROPRIÉTÉ PHYSICOCHIMIQUE; PROTEINS; PROTEÍNAS; PROTÉINE; Secondary wall; GRP(s); PGA; Cellulosic fibre; AGP(s); NCP(s); Galactan; MAb; Glucan; Linum usitatissimum; Arabinogalactan-protein; NMR; RG; Secondary wall; Glycine-rich protein; Proteoglycan; Lignin; Molecular structure; Growth; Cellulose; Plant fiber; Review; Glycine; Fiber crop; Cell wall; Linaceae; Dicotyledones; Angiospermae; Chemical composition; Developmental stage; Structural carbohydrate; Microfibril; Arabinogalactan; Cell differentiation; α-Aminoacid; Phenology; Spermatophyta; Biological accumulation
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2003.07.001

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 that encircle the vascular cylinder. The bundle cohesion is insured by pectins, accumulating in the primary wall and cell junctions. In contrast, lignin, which is present in very low amount, does not seem to play a major role in bundle cohesion. At maturity, secondary wall is characterised by (i) a high level of cellulose with microfibrils locked into an almost axial direction and (ii) 5–15% non-cellulosic polysaccharides (NCPs). The chemical composition of NCPs depends on growth stage, indicating important cell wall remodelling, fibre position and variety. Despite the large disparity of the results reported in the literature, galactose appears to be the predominant sugar of NCPs, and β-1-4-galactan together with rhamnogalacturonan of type I (RG-I) and polygalacturonic acid (PGA) become, with fibre maturity, the most abundant tightly bound NCPs. Glycine-rich proteins (GRPs) and arabinogalactan-proteins (AGPs), also present in flax fibres, are both characterised by appreciable levels of glycine and acidic amino acid and are deficient in hydroxyproline, and may contribute to the cross-linking of pectins. (Galacto)glucomanans/glucans rather than xylans consist of cross-linking polymers in fibre secondary wall. A model is proposed where cellulose microfibrils, tethered by cross-linking (galacto)glucomanans/glucans, are embedded in a pectic matrix.