The Pectic Polysaccharides are Covalently Interconnected

It has been established by many lines of evidence that the neutral pectic polysaccharides, the araban and galactan, are covalently attached to the acidic pectic polysaccharide, rhamnogalacturonan I 45, 123). 

The Hemicelluloses of Primary Cell Walls Bond Strongly to Cellulose 

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There are four major types of polymers in the primary cell walls of dicots hydroxyproline-rich glycoprotein, cellulose, hemicellulose and pectic polysaccharides. The mole percents of these polymers in suspension-cultured sycamore cell walls is presented in Table 8 (45, 75). The pectic polysaccharides are covalently interconnected. The hemicelluloses are non-covalently bonded to the cellulose fibers. There is no known attachment between the hydroxyproline-rich glycoprotein and the other cell wall polymers. The extent of covalent attachment between the hemicelluloses and the pectic polysaccharides is unknown. The fact that removal of the xyloglucans from the cell walls is enhanced by solubilization of the pectic polysaccharides (31, 75, 123) suggests that... 

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