Macromolecular biophysics of the plant cell wall: Concepts and methodology

Abstract

-Plant cell walls provide form and mechanical strength to the living plant, but the relationship between their complex architecture and their remarkable ability to withstand external stress is not well understood. Primary cell walls are adapted to withstand tensile stresses while secondary cell walls also need to withstand compressive stresses. Therefore, while primary cell walls can with advantage be flexible and elastic, secondary cell walls must be rigid to avoid buckling under compressive loads. In addition, primary cell walls must be capable of growth and are subjected to cell separation forces at the cell corners. To understand how these stresses are resisted by cell walls, it will be necessary to find out how the walls deform internally under load, and how rigid are specific constituents of each type of cell wall. The most promising spectroscopic techniques for this purpose are solid-state nuclear magnetic resonance (NMR), and Fourier-transform infrared (FTIR) and Raman microscopy. By NMR relaxation experiments, it is possible to probe thermal motion in each cell-wall component. Novel adaptations of FTIR and Raman spectroscopy promise to allow mechanical stress and strain upon specific polymers to be examined in situ within the cell wall. © 2000 Éditions scientifiques et médicales Elsevier SAS Cellulose / growth / mobility / pectin CP, cross-polarisation / FT, Fourier-transform / IR, infrared / MAS, magic-angle spinning / NMR, nuclear magnetic resonance / T 2 , spin-spin relaxation time constant

Analysis of the Golgi Apparatus in Arabidopsis Seed Coat Cells during Polarized Secretion of Pectin-Rich Mucilage

“…The plant cell wall is a dynamic extracellular matrix, and its organization is integral to its proper function (Somerville et al, 2004;Cosgrove, 2005). The current model for primary cell wall structure proposes a series of macromolecular networks that are intertwined and interconnected to provide the strength and support (Carpita and Gibeaut, 1993;Carpita and McCann, 2000) necessary for the plant to withstand both tension and compression, while at the same time having the ability to grow in a precisely controlled and directed manner (Jarvis and McCann, 2000). One such network is thought to consist of cellulose and hemicellulose.…”

Mechanical Properties of Plant Cell Walls Probed by Relaxation Spectra

“…In vascular plants, more than 200 genes encoding glycosyl transferases, and an unknown number of genes from other families, are probably devoted to the synthesis and assembly of cell wall polysaccharides. The structural complexity of plant cell walls may seem surprising, if conveying mechanical strength to the plant body were their only role, but this is not their only role, as displayed in the review by Jarvis and McCann (2000).…”

Biological research survey for the efficient conversion of biomass to biofuels.

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