Polysaccharides: Plant Noncellulosic

Abstract

Plant cell walls are composites that consist of polysaccharides, proteins and, if they are secondary cell walls, lignin as well as a number of minor constituents. The major components are the polysaccharides and, owing to their complexity, they are usually subdivided into cellulose and others, namely the noncellulosic polysaccharides. These noncellulosic polysaccharides encompass pectins (d‐galacturonans) and hemicelluloses (d‐xylans, d‐glucans, d‐mannans, etc.) and each has its own specific function and responsibility within a particular type of cell wall.

Keywords: hemicelluloses; pectin; function in plant cell wall; biosynthesis; enzymatic degradation

Figure 1.

Structures of an arabinoxylan, a glucomannan, a xyloglucan and a pectin as found in plant cell walls. Ara, arabinose; Fuc, fucose; Gal, galactose; GalA, galacturonic acid; Glc, glucose; Man, mannose; Rha, rhamnose; Xyl, xylose; OAc, acetyl; OMe, methyl.

Figure 2.

(a) Model of the primary cell wall of onion as proposed by McCann and Roberts and (b) model of an expanding type I plant cell wall as proposed by Carpita and Gibeaut . Figure 2a is printed with permission from Academic Press, London and Figure 2b is printed with permission from Blackwell Science, Oxford.

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References

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How to Cite close
Morrison, Ian M(Apr 2001) Polysaccharides: Plant Noncellulosic. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0000696]