Structural characterisation and orientation of cell wall polymers in Arabidopsis thaliana stem

Abstract

Plant cell walls are composed of a framework of cellulose microfibrils that are interconnected with heteropolysaccharides (lignin, hemicelluloses) in a specific manner. Plant cell walls form a large part of the plant body and define its characteristics. Structural organisation of the cell wall and related polymers is important for both mechanical properties of plants and chemical reactions occurring in the wall space, especially in the response to stress.By using imaging FTIR microscopy, run in transmission mode and at different polarisation modes (from 0° to 90°), it is possible to follow the chemical variability and the orientation of cell wall polymers (cellulose, hemicelluloses and lignin) of the Arabidopsis thaliana stem. The polarised FTIR measurements indicated that both xylan and lignin have parallel orientation with regard to the orientation of cellulose. It is believed that this structuring of lignin in the S2 layer of the cell wall might be a result of the spatial constraints within the cell wall, occuring due to the previous deposition of cellulose/hemicellulose in a strongly oriented assembly.