On the biosynthesis of cellulose in higher and lower plants
| Autor: | M. Marx-Figini |
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| Rok vydání: | 2007 |
| Předmět: | |
| Zdroj: | Journal of Polymer Science Part C: Polymer Symposia. 28:57-67 |
| ISSN: | 1935-3065 0449-2994 |
| Popis: | Kinetic experiments on cotton cellulose and cellulose from the alga Valonia show, that the degree of polymerization during the biosynthesis of the secondary wall is independent of conversion and reaction conditions. During the whole synthesis period it remains constant at a DPw ∼ 13,000 for cotton and 16,500 for Valonia, respectively. Fractionation experiments indicate complete uniformity of the degree of polymerization at every stage of the biosynthesis. This means that the biosynthesis of secondary wall cellulose for both higher and lower plants must be a structure-controlled process and not a time-controlled one. Contrary to this evidence the synthesis of primary wall cellulose takes place by another mechanism which results in a lower average degree of polymerization and a nonuniform distribution. Both, secondary wall and primary wall synthesis can occur simultaneously. Recent results of electron diffraction experiments on native cellulose and fibrils, precipitated from the original material, seem to indicate that crystalline and supermolecular structure of the cellulose fibrils are not determined by the biosynthetic process. |
| Databáze: | OpenAIRE |
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