KOH-soluble Fractions Research Articles

Differential changes in cell wall matrix polysaccharides and glycoside-hydrolyzing enzymes in developing wheat seedlings differing in drought tolerance

The growth kinetics and variations in cell wall matrix polysaccharides and glycoside hydrolases during seedling development of the drought-tolerant wheat cultivar (cv. Hong Mang Mai) were compared with the drought-sensitive cultivar (cv. Shirasagikomugi). After 15 d of culture in water at 22 degrees C under constant irradiance of 98 micromol m(-2) s(-1), the length of the coleoptile and leaf sheath of Hong Mang Mai seedlings was 1.7 times longer than those of Shirasagikomugi seedlings. In the cell walls isolated from coleoptiles and leaf sheaths of the seedling of the two cultivars, the contents of arabinose, xylose, and glucose changed during development. The cell walls were fractionated progressively with 50 mM CDTA, 50 mM Na(2)CO(3), 1 M KOH and 4 M KOH, and sugar composition was determined. The amount of CDTA-soluble fraction from the Hong Mang Mai cell walls was 2.4-fold higher than that from the Shirasagikomugi cell walls at 6 d of culture, and a considerable decrease was observed during development. The ratio of arabinose to xylose in 1 M KOH-soluble fraction from the two cultivars decreased. The amount of 4 M KOH-soluble fraction from the Shirasagikomugi cell walls was affected much more than those of the Hong Mang Mai cell walls. Many glycoside hydrolase activities were detected in the protein fractions from coleoptiles and leaf sheaths of the two cultivars, and the activities of licheninase, 1,3-1,4-beta-glucanase, and 1,3-beta-glucanase in the LiCl-soluble protein fraction increased drastically during development of the Shirasagikomugi seedlings. These findings suggest that the metabolism of the cell wall matrix polysaccharides of the drought-tolerant wheat cultivar is far different from that of the drought-sensitive wheat cultivar during seedling development.

Post-harvest heat treatments modify cell wall composition of strawberry (Fragaria×ananassa Duch.) fruit

Abstract ‘Pajaro’ strawberry fruit were treated at 45 °C by hot air or hot water prior to storage at 3 °C for 10 days. Control fruit were stored without treatment. Modifications in cell wall composition and fruit quality caused by heat treatment were assessed after removal of fruit from storage. Treatment with hot water improved fruit resistance to fungal infection, but caused external damage, which rendered fruit commercially unacceptable. Hot air treatment did not affect external appearance, improved resistance to fungal infection and preserved firmness. Heat treatments did not affect cell wall yields obtained, but caused alterations in solubility of the different cell wall polysaccharide fractions. Higher yields for CDTA- and KOH-soluble fractions were observed as a consequence of treatment, suggesting decreased solubilization of cell wall polymers in treated fruit, even though no apparent relationship to fruit firmness was found. Higher degrees of esterification as well as total sugar contents in both CDTA- and KOH-soluble fractions were also found in heated fruit.

Cell Wall Degradation and Structural Changes of GA-induced Watercored Tissues in Japanese Pear 'Akibae' and 'Housui'

We investigated the chemical degradation and structural changes of cell walls of watercored tissues induced by GA paste treatment in Japanese pear (Pyrus pyrifolia Nakai) 'Akibae' and 'Housui'. Depolymerization of high molecular-mass trans-1, 2-cyclohexanediamine-N, N, N', N'-tetraacetic acid (CDTA)-soluble pectin occurred in severely watercored fruits, but there were no such metabolic changes in the Na2CO3-soluble fractions in both cultivars. Hemicellulose in 4% KOH soluble fractions, size-fractionated through a Sepharose CL-6B-100, revealed partial molecular-mass downshifts of total sugars in both cultivars, but considerable mol-mass change of xyloglucan only occurred in 'Akibae'. The polymers in 24% KOH soluble fraction showed no detectable alteration of molecular-mass in both cultivars, whereas 'Akibae' exhibited much higher cell wall-bound polygalacturonases and glycosidases activities compared with 'Housui'. The activities of β-galactosidase and β-glucosidase increased as the zone of watercore expanded in 'Akibae'. Total activity of cell wall bound glycanases was higher in 'Akibae' than in 'Housui'. Catabolism of carboxymethyl cellulose by cellulase was not different between sound and watercored tissues in both cultivars, but the activity against xyloglucan was higher in watercored tissue than the sound tissue adjacent to the watercore zones in 'Akibae'. Structural changes observed by light microscopy in sound and severely watercored tissue showed a greater extent of cell separations with the accumulation of pectic materials in the intercellular space of severely watercored tissues in 'Akibae' than in 'Housui'.

Constitutive overexpression of a ripening-related pepper endo-1,4-beta-glucanase in transgenic tomato fruit does not increase xyloglucan depolymerization or fruit softening.

The ripening-related pepper endo-1,4-beta-D-glucanase (EGase) CaCel1 was over-expressed in transgenic tomato plants under the control of the constitutive 35S promoter to investigate the effects on plant growth and fruit softening of high levels of a potential cell wall-degrading activity. In transgenic fruit, recombinant CaCel1 protein was associated with a high-salt putative cell wall fraction, and extractable CMCase activity was increased by up to 20-fold relative to controls. However, the effects of high levels of EGase activity on fruit cell wall metabolism were relatively small. The largest consequence observed was a decrease of up to 20% in the amount of matrix glycans in a 24% KOH-soluble fraction consisting of polysaccharides tightly bound to cellulose. This decrease was confined to polysaccharides other than xyloglucan, did not affect the size distribution of remaining molecules, and was not correlated with a corresponding increase in glycans in a 4% KOH-soluble fraction loosely bound to cellulose, suggesting that the missing polymers had been degraded to fragments small enough to be lost from the extracts. The amount of matrix glycans in the 4% KOH-soluble fraction was not substantially changed, but the size distribution showed a small relative increase in the amount of polymers in a peak eluting close to a linear dextran marker of 71 kDa. This could be due either to an increase in the amount of polymers of this size, or to a loss from the extract of other polymers present in peaks of higher molecular weight. Transgenic fruit were not softer than controls but appeared the same or slightly firmer at both green and red developmental stages, and no differences in plant vegetative growth were observed. CaCel1 did not cause depolymerization of tomato fruit xyloglucan in vivo, but differences in the amount or molecular weight profile of other matrix glycans were observed. The data suggest that degradation of a proportion of matrix glycans other than xyloglucan does not result in fruit softening, and that fruit softening is not limited by the amount of EGase activity present during ripening.

Comparison of cell wall components between Fragaria × ananassa and Fragaria chiloensis grown in Chile

SummaryFruit firmness and cell wall composition were compared among five cultivars of F. × ananassa (‘Chandler’, ‘Seascape’, ‘Tudla’, ‘Hokowase’ and ‘Reiko’) and two land races of F. chiloensis (‘94BAU-1A’ and ‘97PUR-1A’) grown in central Chile. Fruits of F. chiloensis were smaller than those of F. × ananassa. Firmness of epidermal tissue did not differ significantly between F. × ananassa and F. chiloensis. Firmness of cortical tissue, however, was significantly lower in F. chiloensis than in F.× ananassa and as a result, difference in the firmness between epidermal and cortical tissues was significantly greater in F. chiloensis than in F. × ananassa. Calcium concentration was low in ‘Reiko’ and ‘Hokowase’ while high in the other varieties of F. × ananassa. F. chiloensis showed intermediate values between these two groups. Higher levels of total uronic acid and neutral sugars in cell wall fractions of F. chiloensis as compared with F. × ananassa were mainly due to its high concentration in the water soluble fraction. Total uronic acid in cell wall fraction was significantly higher in F. chiloensis than in F. × ananassa, mainly due to significantly higher concentrations in the water-soluble fraction. Non-cellulosic neutral sugars, especially arabinose in the water, CDTA, and Na2CO3-soluble fractions were significantly higher in F. chiloensis than in F. × ananassa. On the other hand, galactose in the CDTA-, Na2CO3-, and KOH-soluble fractions was significantly lower in F. chiloensis than in F. × ananassa. Moreover, cellulose concentration of F. chiloensis was also significantly lower than that of F. × ananassa. Results obtained from cell wall analysis suggest that softer cortex in F. chiloensis might be due to either lower cellulose content, higher solubilization rate of pectic substances, and/or compositional differences in the branching of neutral sugars.

Metabolism of cell wall polysaccharides in cell suspension cultures of Populus alba in relation to cell growth

Changes in the composition of cell walls and extracellular polysaccharides (ECP) were studied during the growth of suspension-cultured Populus alba cells. Three growth phases, namely the cell division phase, cell elongation phase and stationary phase, were distinguished. The active deposition of polysaccharides in cell wall fractions (50 mM Na 2 CO 3 -, 1 M KOH-, 4 M KOH-soluble and 4 M KOH-insoluble) was observed during the elongation phase. A 50 mM Na 2 CO 3 -soluble pectic fraction mainly composed of 1,4-linked galactan and arabinan except acidic sugars. The 1,4-linked galactan decreased markedly during elongation. In I and 4 M KOH-soluble hemicellulosic fractions, non-cellulosic 1,4-glucan and xyloglucan were observed as major components, respectively. These polysaccharides also decreased during elongation. A large amount of polysaccharides was secreted into the medium as ECP. Neutral sugars were detected predominantly by sugar composition analysis. Acidic sugars, such as galacturonic acid, were less than 12% of total. In this study, active metabolism of pectic polysaccharides in addition to hemicellulosic polysaccharides, especially neutral side chains of pectin, during cell growth, was clarified.

A study of the intervarietal differences of cotyledon and seed coat carbohydrates in soybeans

A selection of food grade soybean varieties from Canada and Japan, and an experimental line which produces a high proportion of ‘stone seeds’, were separated into seed coat and cotyledon. Following the removal of oil and protein, the samples were fractionated into polysaccharide groups, first by solubility in water and then secondly in a scheme using aqueous ethanol, sodium carbonate and KOH. The subfractions were hydrolysed using 1 M and 12 M sulfuric acid then analysed by HPLC for monosaccharides and by a colourimetric method for uronic acids. The results showed that there was very little intervarietal difference in the carbohydrate composition of the cotyledons but there were some significant differences in the seed coat composition. A high concentration of xylose was found in the KOH soluble hemicellulose fractions which was highest in the stone seed sample and lowest in the Japanese varieties.

Turnover of white asparagus cell wall polysaccharides during postharvest storage.

The main polysaccharides involved in asparagus cell wall turnover have been identified. Homogalacturonans are lost from both the apical and basal sections of the spear. Galactans are mobilized from the cellulose residue of the apical section and recovered in the KOH-soluble fractions while they are lost from the cellulose residue of the basal section. Xyloglucans are incorporated in the apical region and degraded from the basal one. Cellulose is incorporated in the basal region and lost from the apical one, and acidic xylans are incorporated in high amounts in the basal section of the spear.

Modification of cell-wall polymers of onion waste—Part I. Effect of pressure-cooking

The extraction of polymers from onion cell walls and the mechanical properties of onion tissues can be modified by heating. However, there is little information on the effects of thermal treatments on the chemistry of cell-wall polysaccharides of onion tissues. The present work reports pressure-cooking-induced changes in cell-wall polymers of onion waste. The outer fleshy scale leaves of onion ( Allium cepa L. cv. Delta and Hysam) were subjected to a range of pressure-cooking times (0, 10, 20, 30 and 50 min, 120°C). Cell-wall material was prepared as cold-alcohol-insoluble residues and subsequently extracted with buffered phenol. The cell-wall material was then extracted sequentially with water, NaCl, imidazole, cyclohexane- trans-1,2-diaminetetraacetate (CDTA), Na 2CO 3 and KOH to leave a residue. The samples were analysed for their carbohydrate composition, their degree of methylesterification and the molecular size of selected soluble polysaccharides. Pressure-cooking-induced softening of onion tissue involved cell-wall swelling and cell separation. This was accompanied by an increase in water-soluble pectic polysaccharides and a decrease in the pectic polymers of the imidazole, CDTA, Na 2CO 3 and KOH-soluble fractions and insoluble residue. Pressure-cooking also resulted in a slight decrease in the peak molecular weight of water-soluble polysaccharides.

Solubilization of Cell Wall Polysaccharides from Olive Fruits into Treatment Liquids during Spanish Green Olive Processing

During Spanish green olive processing, several samples of fruits and liquids were taken. Cell walls of olive fruits were isolated and fractionated, and the liquids were analyzed by HPLC. During the lye treatment and wash, an exchange of arabinans from carbonate-soluble and 4 M KOH-soluble fractions to the water-soluble was observed, and a partial solubilization into the liquids was quantified (the average molecular weight of portions solubilized was 6 kDa). The main change in pectins was a movement of homo- and rhamnogalacturonans from water-soluble and carbonate-soluble fractions to the imidazole-soluble fraction during lye and wash due to high pH, but another minor one occurred: a partial solubilization of alkali-soluble and cellulose-linked pectins during lye treatment, wash, and fermentation. Around 3 mg/fruit of cellulose was also solubilized, mainly during lye and wash. Only a small part of this was recovered as oligo- and/or polysaccharides of molecular weight >1000 kDa. A very accurate balance wa...

‘イエロー紅心’キウイフルーツ果実の樹上軟化に伴う細胞壁多糖類の経時変化

In studying the mechanism of softening of in kiwifruit (Actinidia chinensis Planch. cv. Yellow Koshin) on the vine, the changes of cell wall polysaccharides were compared with those induced by ethylene treatment. Cell wall polysaccharides were prepared from 80% alcohol-insoluble residue (AIR) by extracting the AIR with water, EDTA, HCI, and KOH in succession as described by Yoshioka et al. (1992 ; 1994). The decrease in the amount of monosaccharides in the water-insoluble fraction (WIF) derived from EDTA, HCl, and KOH soluble fractions was followed. 1. Ethylene evolution was not detected in the fruit during softening on the tree. 2. Fruit softening on the vine was accompanied with a decrease in galacturonic acid, but not of neutral sugars in the WIF. 3. Ethylene treatment led to a drastic decrease in rhamnose, arabinose, and galactose levels in the WIF ; galacturonic-acid decreased with or without the ethylene treatment. These findings suggest that fruit softening on the vine is associated with the dissolution of homogalacturonan which is insensitive to ethylene. Furthermore, ethylene treatment seems to induce the solubilization of homogalacturonan and rhamunogalacturonan, followed by fruit softening.

Degradation of Pectic Polysaccharides in Pickled Green Olives

The changes that occur in the pectic fractions in the cell wall of olives of the Manzanilla variety (Olea europaea pomiformis) during processing (initial treatment at high pH and subsequent lactic fermentation) have been researched. After studying various conditions for fractionating the pectic polysaccharides, the most adequate were chosen, involving sequential extraction with water, imidazole-hydrochloric acid buffer, sodium carbonate, 1M potassium hydroxide, and 4M potassium hydroxide. In the unprocessed fruit, the fractions studied consist mainly of high-molecular-weight acidic polysaccharides (70 to 250 kDa): homogalacturonans, rhamnogalacturonans, and branched arabinans. These were found in different proportions depending on the extraction agent used. At the same time, significant amounts of relatively low-molecular-weight (10 to 10.5 kDa) neutral branched arabinans were found in the water-soluble fraction. As a result of the processing, changes occurred in the proportions of the different groups of polysaccharides in accordance with changes in their solubility characteristics. These changes were reflected in the processed fruit by (i) an increase in the neutral branched arabinans in the water-soluble fraction due to the increased presence of such polysaccharides originally found in the carbonate and 4M KOH-soluble fractions; (ii) an increase in homogalacturonans and rhamnogalacturonans, without significant changes in molecular weights, in the imidazole-soluble fraction as a result of the increased presence of corresponding polysaccharides originally found in the carbonate-soluble and water-soluble fractions; (iii) a substantial increase in uronic acids in the 1M potassium hydroxide-soluble fraction, preferentially as low-molecular-weight polysaccharides; and (iv) a solubilization of arabinans in the 4M potassium hydroxide-soluble fraction.

Chemical and structural features of kiwifruit cell walls: Comparison of fruit and suspension-cultured cells

Chemical and structural features were compared in cell-wall polysaccharides isolated from intact kiwifruit ( Actinidia deliciosa) and suspension-cultured cells initiated from the same fruit. Morphological features of the cells and whole fruit tissue were also examined by electron microscopy. Cell-wall material (CWM) from cultured cells contained less cellulose, more protein, and had a higher degree of acetylation than cell-wall material from intact fruit. Whereas galactose was the major neutral sugar in the pectic polysaccharides of intact fruit, arabinose was predominant in cultured cells. The arabinose occurred as terminal and 5-substituted residues, presumably as neutral side-chains attached to the galacturonan backbone which was more highly branched in the cultured cells. The most significant structural difference in the hemicelluloses occurred in a galactoglucomannan purified from the 4 M KOH-soluble fraction. The backbone of the galactoglucomannan of the cultured cells was more branched than that in the intact fruit, with 84% of the 4-linked mannosyl residues substituted at O-6 with either single galactosyl or galactosyl-(1 → 2)-galactosyl groups. In intact fruit ∼ 30% of the mannosyl residues were substituted at O-6. Rhamnogalacturonan II (RG-II) was partially purified from CWM and shown to possess a very similar composition of glycosyl residues in both intact fruit and cells. However, the primary cell walls of the cultured cells contained twice the amount of RG-II found in the cell walls of intact fruit.

Polysaccharides from the Cell Walls of Pineapple Fruit

Cell wall material from pineapple fruit was obtained and sequentially extracted with 50 mM NaOH at 2 o C, 1 M KOH at 2 and 20 o C, and 4 M KOH at 20 o C. From the 4 M KOH-soluble fraction, a «neutral» polysaccharide and an acidic one were isolated by chloride anion exchange chromatography. The «neutral» fraction was composed of xylose, arabinose, glucose, galactose, and minor quantities of mannose. The infrared spectra showed an absorption band at 900 cm -1 of β-linked polysaccharides. The methylation analysis revealed the main glycosidic linkages of the «neutral» polysaccharide: 1,4-linked xylose with branching points in C 3 and C 2 , 1,4-linked glucopyranose with branching points in C 6 , and terminal glucopyranosyl, arabinofuranosyl, and arabino/xylopyranosyl residues

The Oligosaccharide Units of the Xyloglucans in the Cell Walls of Bulbs of Onion, Garlic and their Hybrid

Xyloglucans were isolated from the 24% KOH-soluble fraction of the cell walls of bulbs of onion (Allium cepa), garlic (Allium sativum) and their hybrid. The polysaccharides yielded single peaks upon gel filtration with average molecular weights of 65,000 for onion, 55,000 for garlic and 82,000 for the hybrid. Compositional analysis of the oligosaccharide units after digestion with an endo-1,4-beta-glucanase from Streptomyces indicated that the polysaccharides were constructed of four kinds of repeating oligosaccharide unit, namely, a decasaccharide (glucose/xylose/galactose/fucose, 4 : 3: 2 : 1), a nonasaccharide (glucose/xylose/galactose/fucose, 4 : 3 : 1 : 1), an octasaccharide (glucose/xylose/galactose, 4 : 3 : 1), and a heptasaccharide (glucose/xylose, 4 : 3). The xyloglucan from the hybrid contained highly fucosylated units that resembled those from onion rather than from garlic. The analysis also revealed that the xyloglucans from Allium species contain highly substituted xylosyl residues with fucosyl-galactosyl residues, suggesting that these monocotyledonous plants resemble dicotyledons in the structural features of their xyloglucans.

Inhibition of growth and development of tobacco hornworm (Lepidoptera: Sphingidae) larvae by cyromazine.

When fed to larvae of tobacco hornworm, Manduca sexta (L.), cyromazine strongly inhibited normal growth and development. Depending on the dose or period of feeding, symptoms were cuticular melanization, swellings in intersegmental regions, cuticular lesions, rupture of the body wall, and death. At greater than 10 ppm, cyromazine in the diet initiated symptoms in fifth instars, whereas greater than 20 ppm induced symptoms which led to death during the instar or at molting. The ratio of chitin to larval body weight in both cyromazine-exposed and control fifth instars increased slightly from ecdysis to 42 h. However, this ratio did not differ between the two groups, indicating that cyromazine had no immediate or direct effect on chitin production. When cyromazine was ingested by fifth instars, it was excreted rapidly, and a small amount (less than 5%) was metabolized to melamine. The amount of cyromazine found in the hemolymph remained relatively constant during the feeding period, whereas the amount present in the body wall increased with time and was localized in the KOH-soluble fraction. Cyromazine may inhibit growth or expansion of the body wall (or both) sufficiently to prevent normal internal growth, producing the observed symptoms and leading to abnormal development.

Cell-wall polysaccharides of kiwifruit ( Actinidia deliciosa): Chemical features in different tissue zones of the fruit at harvest

Cell-wall material (CWM) was isolated from cryo-milled (− 196°) powders prepared from 4 different tissue zones of kiwifruit ( Actinidia deliciosa). Polysaccharides were solubilised by stepwise extraction with cyclohexane- trans-1,2-diaminetetra-acetate (CDTA), 0.05 m Na 2CO 3, 6 m guanidinium thiocyanate (GTC), and 4 m KOH. A heterogeneous mixture of pectic galactans accounted for 40–50% of the CWMs, while hemicelluloses, the bulk of which were xyloglucans, accounted for 15–25%. Each tissue zone contained similar types of polysaccharide. Variability in their amount and sugar composition are thought to reflect different stages in the physiological development of the fruit at harvest, in the 4 zones. Polymers from the outer pericarp tissue were fractionated by anion-exchange chromatography and subjected to methylation analysis. The CDTA- and Na 2CO 3-soluble polymers were rhamnogalacturonans substituted to varying degrees with galactan and arabinogalactan side-chains containing 4-, 2,4-, 3,4- and 4,6-linked galactose and 5- and 3,5-linked arabinose. Side chains were terminated by galactose and arabinose and lesser amounts of rhamnose, fucose, xylose, and galacturonic acid. The pectic polysaccharides of the GTC- and KOH-soluble fractions had more highly branched rhamnogalacturonan backbones than the CDTA- and Na 2CO 3-soluble polymers and contained hemicellulosic elements. The major hemicellulose was a xyloglucan, but lesser amounts of a 4- O-methylglucuronoxylan and a branched mannan were partially characterised. Several polymers were associated with proteins low in hydroxyproline. Evidence is presented that a polysaccharide of the rhamnogalacturonan II type is associated with the pectic polymers of kiwifruit.

Investigation of the heterogeneity of xyloglucans from the cell walls of apple

Cell-wall material from parenchymatous tissues of apple was sequentially extracted with 50m m NaOH at 1°, m KOH at 1° and 20°, and 4 m KOH at 20°, to leave a residue of α-cellulose. From the 4 m KOH-soluble fraction, a crude xyloglucan was isolated by anion-exchange chromatography, and further resolved into seven xyloglucans by borate anion-exchange chromatography. The relative amounts of the xyloglucans, in order of elution, were 2.7:1.3:29.7:1.0:3.2:1.2:10.3. The structural features of five of the xyloglucans were determined by methylation analysis. These results show that apple xyloglucans exhibit heterogeneity.

Isolation and partial characterisation of a xyloglucan from the cell walls of Phaseolus coccineus

Cell-wall material from Phaseolus coccineus was fractionated by successive extraction with aqueous inorganic solvents. From the 4 m KOH-soluble fraction, a polymer composed of l-arabinose (4.2%), l-fucose (6.0%), d-galactose (9.3%), d-xylose (34.1%), and d-glucose (46.4%) was isolated and purified by ion-exchange and cellulose column chromatography; the product was homogeneous by moving-boundary electrophoresis and ultracentrifugation. The S 20,w o and D obs were 2.92 S and 1.7 × 10 −7, respectively, and the molecular weight was ∼110,000. Methylation analysis suggested a (1→4)-linked glucan backbone with ∼3 out of 4 glucosyl residues substituted through O-6 with xylose or oligosaccharides terminating in galactose, fucose, and arabinose. Limited acetolysis gave several di- and tri-saccharide derivatives of which four [ d-Gal p-(1→2)- d-Xyl p, d-Glc p-(1→4)- d-Glc p, l-Fuc p-(1→2)- d-Gal p-(1→2)- d-Xyl p, and d-Glc p-(1→4)- d-Glc p-(1→4)- d-Glc p] were tentatively identified. Specific glycosidases were used to determine the configuration of the glycosidic linkages. The backbone was shown to be a (1→4)-β- d-glucan and the l-fucosyl groups were α. Neither α- nor β- d-galactosidase removed d-galactose. The structure of the xyloglucan is discussed in relation to other cell-wall polymers, especially cellulose.

An arabinogalactoxyloglucan from the cell wall of Solanum tuberosum

Cell-wall material from potatoes was fractionated by successive extractions with water at 80°, 0.2 M (NH 4) 2C 2O 4 at 80°, 1 M and 4 M KOH, to leave a residue of α-cellulose. The compositions of the isolated carbohydrate polymers were determined by sugar and methylation analysis. From the 4M KOH-soluble fraction an arabinogalactoxyloglucan was isolated and (partially) characterized by methylation analysis of the undegraded polymer and partially degraded methylated polymer. Methylation analysis of the oligosaccharides produced on treatment of the xyloglucan with cellulase threw additional light on the structural features of the polysaccharide. The results show that the xyloglucan has a cellulosic backbone which is highly substituted at position 6 with xylopyranose residues, some of which, in turn, carry either arabinofuranose or galactopyranose residues, as a substituent on position 2. The significance of these results is discussed.