Mannan from plant cell-walls

A number of plant [106, 178-183] and algal [64, 176] polysaccharides have structures based on a P(l-4)mannan main chain - P(l-4)mannan, a(l-6)galacto-P(l-4)-D-mannan and the related P(l-4)-D-glucomannan and galacto-P(l-4)glucomannan. They serve as cell wall structural material and as carbohydrate reserve polymers. An unbranched P(l-2) mannan of low molecular weight has been reported from the insect flagellate Herpetomonas samuelpessoai [184]. 

Mannans. A variety of other polysaccharides may occur in the cell walls of land plants. Among these are mannans, galactans, and pectic substances. In general, softwoods contain approximately 11% combined D-mannose, whereas hardwoods contain only about 1 %. A linear mannan is also the chief constituent of the thickened cell walls of palm seeds, where it occurs as a food reserve and disappears on germination. A rich source is the endosperm of the tagua palm which is known as vegetable ivory and from which buttons have been made. This mannan is a linear chain of D-mannopyranose... 

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