Dynamique du positionnement de la cellulose dans les parois des fibres textiles du lin (Linum usitatissimum)

Abstract

Summary The cell wall of stem fibers of flax shows the classical cellulosic architecture with three main domains with constant slope (S1, S2- thickened and locked into an almost axial direction -, S3) within which the microfibril orientation remains parallel (unidirectionnal, the so-called “spiral texture”). The present paper focus on the fact that arced change of orientation occurs at the major wall layer interfaces. The nested arcs are cancelled or reversed by tilting of the goniometric stage at the electron microscopy level; they are transient cholesteric analog (multidirectional helicoids). Structural models are provided giving unified picture of the flax fiber wall according space and time. Data are consistant with a possible dual mechanism controlling the cellulosic framework morphogenesis: cooperation between a directed assembly (via the plasmalemma) and a liquid crystal-like self assembly. The secondary cell wall of fibers with intermittent cholesteric pattern is compared to the secondary cell wal...