| Summary: | 碩士 === 國立臺灣大學 === 農業化學研究所 === 54 ===
Bamboo shoot polysaccharides were fractionated into 1 N KOH soluble, 4 N KOH soluble and 4 N KOH insoluble fractions, and they were studied by the methods of structural polysaccharide cbemistry.
The KOH soluble polysaccharide was partially hydralyzed with acid and the oligosaccharides produced were separated on a charcoal column and also by paper chromatography. Several di - and tri - saccharides, which could be obtained in chromatographically pure form, were subjected to structural analyses by partial hydrolysis, NaBH4 reduction and periodate oxidation. From the data obtained, following structures were given:
(1) D - glucopyranosyl (1→3) - D -glucopyranose
(2)β - D - xylopyranosyl (1→ 4) - D - xylopyranose
(3) D - glucopyranosyl (1→ 3) - D - xylopyranosyl (1→ 4) - D - xylopyranose
(4) D - glucopyranosyl (1→ 4 or 1→ 2) - D - xylopyranosyl (1→ 4) - D - xylopyranose
(5) D - xylopyranosyl (1→ 4) - D - xylopyranosyl (1→ 4) - D - xylopyranose
(6) D - galactopyranosyl (1→ 6) - D - galactopyranose
(7) D - xylopyranosyl (1→3) - D - glucopyranosyl(1→3) - D -glucopyranose
(8) D - galactosyl - L - arabinose
From the structures of these oligosaccharides and the pentosan content and the glucose / galactose / and xylose / arabinose ratios of the poly - saccharide fractions, it is concluded that the bamboo shoot cell wall consists of two types of hemicellulosic polysaccharides; namely, an arabogalactan and a glucoxylan. The arabogalactan consists of 1 → 6 linked D - galactose unit as the main chain and L - arabinose and / or D - galactose as the side chain. The glucoxylan consists of D - xylose units linked by N -1, 4 as the main chain and D - glucose untts linked by (1→3) as the side chain. The glucoxylan side chain may be terminated by D - xylose linked by (1→3) linkage.
The cellulase hydrolysis of the 1 N and 4 N KOH insoluble fractions, as performed by Dr. J. G. Su, shows that under the identical hydrolysis condition, 1 N, KOH insoluble material produced both D - xylose and L - arabinose and that 4 N KOH insoluble residue produced L - arabinose but no xylose. The mole ratios glucose / galactose and xylose / arabinose determined on the 1 N and 4 KOH soluble polysaccha rides indicate that both arabinose and galactose are richer in the 4 N alkall soluble fractions than in the 1 N alkali soluble one. From these facts, it is proposed that the spatial arrangement of the bamboo shoot cell wall polysaccharides is such that the cellulose micells associate with arabogalactan more intimately than with glucoxyan.
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