Abstract
1. O-Acetylated polysaccharides were obtained from green wood of both sweet chestnut and wych elm by treatment of the residue remaining after dimethyl sulphoxide extraction with water at 98°. This gives a mixture of polysaccharides containing xylose, galactose, glucose and uronic acids. Analysis of these and their fractionated products suggest that only xylans in green sweet chestnut and green wych elm are O-acetylated. 2. The isolated O-acetylated xylans are not representative of the total O-acetylated xylans occurring in sweet chestnut and wych elm. 3. Application of the method developed by Bouveng for the location of O-acetyl groups to all four O-acetylated xylans obtained in this series of investigations by dimethyl sulphoxide extraction showed that those from sweet chestnut and wych elm, under the same conditions of incubation, lost: 74·2 and 43·4% of acetyl groups respectively, at C-2; 58·0 and 28·5% of acetyl groups respectively at C-3; 41·8 and 82·2% of acetyl groups respectively at C-2 and C-3. 4. A consideration of electronic and steric factors indicates that there does not appear to be a purely chemical reason for the difference in loss of O-acetyl groups between sweet chestnut and wych elm. It is suggested that the location of O-acetylated xylans in the wood cell walls and the presence of extractive may play some part in this difference.
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Selected References
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- Cochrane G. C., Gray J. D., Arni P. C. The emission of corrosive vapours by wood. Sweet-chestnut (Castanea stiva) and wych-elm (Ulmusglabrau) O-acetyl-4-O-methylglucuronoxylans extracted with dimethyl sulphoxide. Biochem J. 1969 Jun;113(2):243–252. doi: 10.1042/bj1130243. [DOI] [PMC free article] [PubMed] [Google Scholar]
- THORNBER J. P., NORTHCOTE D. H. Changes in the chemical composition of a cambial cell during its differentiation into xylem and phloem tissue in trees. 3. Xylan, glucomannan and alpha-cellulose fractions. Biochem J. 1962 Feb;82:340–346. doi: 10.1042/bj0820340. [DOI] [PMC free article] [PubMed] [Google Scholar]
- THORNBER J. P., NORTHCOTE D. H. Changes in the chemical composition of a cambial cell during its differentiation into xylem and phloem tissue in trees. II. Carbohydrate constituents of each main component. Biochem J. 1961 Dec;81:455–464. doi: 10.1042/bj0810455. [DOI] [PMC free article] [PubMed] [Google Scholar]