Changes In Carbohydrate Content Research Articles

Ecological drought resistance and adaptability of apple varieties

For adequate yields in apple plantations, during the long growing period of the fruit primordia, one of the decisive factors is water supply. Indicators of stress are valuable signs for the diagnosis of drought and necessity of watering, i.e. planning the irrigation of plantations. The aim of the present study was to find reliable signs of water stress on apple trees and at the same time conclude on the drought tolerance of different varieties. The plantation of apple varieties grafted on various stocks and cultivated according to different systems (irrigated, non irrigated, integrate and biological) has been examined continuously by leaf analysis. Along the period of growing fruits, measurements were made in the field, then the leaf samples were analysed in the laboratory for composition of pigments, carbohydrates and antioxidants, as well as the histology of the tissues checked. Without irrigation, the mean leaf mass and the relative chlorophyll content (SPAD) of the variety Idared on M4 stocks increases beyond the values of 50 SPAD, whereas on M26 stock and integrated system, it declines. In the collection of varieties, grown according to the „integrated” system, during the development of fruits, ‘Gála’ and ‘Remo’ varieties have been affiliated to the “less susceptible” group regarding drought tolerance because of the leaf morphology, structure and content of SPAD and antioxidants. However, ‘Idared’ and ‘Jonagold’ belong to the “susceptible” group. To the same group are ranged the ‘Akane, Red Rome vanWell, Pink Lady’ varieties. Those varieties reacted to a short period of drought by increased production (content) of carbohydrates. Regarding changes of carbohydrate content ‘Greensleeves’ and ‘Ozark Gold’ varieties belong to the moderately water dependent (requiring) group. In the field, SPAD-tests facilitated the measurement of nutrient-uptake and incorporation, which is proved by the tight correlation between the data of SPAD and the increment of leaf weight (r=0.76–r=0.88), however, this depends on the variety too. SPAD is an indicator of water supply and is related with the density of stomata, cannot used for the selection of water-exigent varieties but for (drought) tolerant ones. In integrated culture, the (drought) susceptible varieties display (water-soluble) hydrophilic and lipophilic antioxidants (ACWand ACL resp.) the quantity of which may have some role in drought tolerance.

Nitrogen Application Rate and the Change in Carbohydrate Concentration in Leaves, Fruit, and Canes of Gold Kiwifruit

ABSTRACT Gold kiwifruit (Actinidia chinensis Planch. var. chinensis ‘Hort16A’) is an important crop for New Zealand. In this trial, all nutrients, except nitrogen (N), were applied at levels comparable to commercial practice. The control treatment received approximately 145 kg N/ha/y, a conservative rate of N application for kiwifruit. The zero-N treatment vines received all nutrients except N, and the high-N treatment received double the control levels of N. Carbohydrate concentrations in the leaves, fruit and canes of zero-N and high-N vines were determined periodically through the season for two years. There were lower total sugar concentrations in the leaves of the zero-N vines however total carbohydrate concentration content was higher in the zero-N fruit. Vegetative vigor was reduced in the zero-N vines when compared to the high-N vines. By reducing N, the partitioning of carbon to fruit appears favored. This effect may be due to modified sink strength under reduced N.

Significance of diatom-derived polymers in carbon flow dynamics within estuarine biofilms determined through isotopic enrichment

Pennate diatoms are the main group of primary producers in transient microbial biofilms at the sediment surface in muddy intertidal systems. These microalgae produce a substantial quan- tity of extracellular polymeric substances (EPS) that contribute significantly to the cohesive proper- ties observed in biofilms. Changes in carbohydrate content and composition and the persistence of diatom EPS were demonstrated with pulse-chase NaH 13 CO3 labeling and simultaneous detection of isotopic enrichment in polysaccharides and phospholipid fatty acids (PLFAs) in Colne Estuary, UK, biofilms over a 48 h period. Significant isotopic enrichment of glucan indicated that a large propor- tion of fixed carbon was initially sequestered into intracellular chrysolaminaran, and labeled carbon was also quickly used for production of the diatom PLFA 20:5ω3 and EPS. Saccharides in the EPS fractions were enriched rapidly, followed by labeling of distinct bacterial PLFAs through hetero- trophic utilization of EPS within 4 h. Maximal isotopic enrichment of diatom and Gram-negative bac- terial PLFAs and hot water- and hot bicarbonate-soluble EPS fractions occurred after 4 h, and 13 C- labeling increased in Gram-positive bacterial PLFAs throughout the study period. After 48 h, PLFAs remained highly labeled relative to diatom-derived polysaccharides, indicating persistence of assim- ilated C in organisms within the biofilms through time and rapid turnover of polysaccharide pools within the biofilms. Coupled pulse-chase isotopic labeling and simultaneous tracking of 13 C in poly- saccharides and PLFAs directly demonstrated the flow of carbon between biofilm autotrophs and het- erotrophic bacteria and the significance of diatom-derived carbohydrates in this exchange.

Regulation of flower development in Dendrobium crumenatum by changes in carbohydrate contents, water status and cell wall metabolism

The involvement of carbohydrates, water potential, cell wall components and cell wall-based enzymes in regulating flower development in Dendrobium crumenatum was investigated. Plants were subjected to cold treatment to release floral buds from dormancy, and the various parameters were investigated from young floral bud stage till flower senescence. Development of floral buds was accompanied by progressive decrease in concentrations of fructans and starch. Upon full flower opening, concentration of soluble sugars was maximum, accompanied by a more negative water potential. High pectin methylesterase activity was observed during early bud development and decreased thereafter. Significant increase in activities of β-galactosidase, β-mannosidase and β-xylosidase was also observed during floral bud development. The cell walls of sepals and petals were modified extensively during floral bud and flower development, as observed by changes in the amounts of celluloses, hemicelluloses and total pectin. Pectin solubilisation was also observed to commence during early floral bud development. These results indicated that carbohydrate hydrolysis, osmotic changes and cell wall dissolution that began early in young floral buds, all regulated flower development in this sympodial orchid. Possible applications of the findings in the horticultural industry are discussed.

Effects of exogenous abscisic acid (ABA) on cucumber seedling leaf carbohydrate metabolism under low temperature

Seedlings with four true leaves of cucumbers (Cucumis sativus L.), Guonong No.25 (a cold-tolerant cultivar) and Guonong No.41 (a cold sensitive cultivar), were grown under normal or low temperature conditions: 25°C/18°C or 15°C/8°C (day/night). The seedlings of Guonong No.25 under low temperature were also treated with or without exogenous ABA. The purpose of our study was to find out the effects of low temperature and exogenous ABA application on the carbohydrate metabolism in the cucumber plants. Time course changes of carbohydrate contents and activities of stachyose synthase and alkaline α-galactosidase in the seedling leaves were investigated after the treatment. Our results show that compared to the seedlings under temperatures of 25°C/18°C, the seedlings of the both tested genotypes under 15°C/8°C (day/night) have significantly higher contents of all measured soluble carbohydrates. Significant difference in stachyose synthase activity is observed between the two genotypes under normal temperature or low temperature. Under normal temperature, leaf stachyose synthase activity in Guonong No.41 is higher than that in Guonong No.25. The stachyose synthase activity of Guonong No.41 decreases sharply under low temperature, but that of Guonong No.25 increases 3 days after treatment and then decreases to the original level. In contrast, there is no significant genotypic difference in alkaline α-galactosidase activity. Additionally, compared to the control seedlings treated with 0 μM ABA, the seedlings treated with 50 and 150 μM ABA accumulate substantial amounts of all tested soluble carbohydrates except galactose whereas 250 μM ABA treated seedlings show decreased levels of all these soluble carbohydrates. Stachyose synthase activity increases significantly upon 50 and 150 μM ABA treatments.

Variation in Endogenous Gibberellins, Abscisic Acid, and Carbohydrate Content During the Growth Cycle of Colored Zantedeschia spp., a Tuberous Geophyte

Phenologic changes and variation in the level of endogenous gibberellins (GAs), abscisic acid (ABA), carbohydrate content, and α-amylase activity were examined in colored Zantedeschia spp. cv. Cala Gold. These changes were examined in the primary bud tissues and in the attached tuber tissue during the growth cycle. Dormant tubers were dry-stored at 20°C for 3 months, planted in a phytotron, and grown under 22/16 ± 1°C. Plant development was monitored under continued irrigation until leaf senescence and tuber dormancy. GAs and ABA were extracted from the primary bud tissues, fractionated by HPLC, and analyzed using GC-SIM. Starch, glucose, soluble protein, and α-amylase activity were monitored in the tuber tissue attached to the primary bud. Endogenous changes in GAs and ABA in the primary bud were correlated with endogenous changes in carbohydrate content and α-amylase activity in the attached tuber tissue. These correlations were observed during the rest and the growth periods and were associated with developmental changes in the plant, that is, bud dormancy relaxation, bud growth, and inflorescence differentiation. ABA content decreased and a transient pulse of GA was measured in the primary bud concomitantly with the onset of shoot elongation in dry tubers during storage, before planting. The sharp increase of GAs in the bud preceded inflorescence differentiation as observed in dissected apices by about 15 days, as well as the increase in α-amylase activity in the attached tuber tissue. A steep decrease in starch level was measured in the tuber after planting, concomitantly with massive plant growth. These findings suggest a possible involvement of gibberellin in the initiation of α-amylase activity during dormancy relaxation in colored Zantedeschia and in the autonomous induction of flowering.

Effect of cooking and soaking on physical, nutrient composition and sensory evaluation of indigenous and foreign rice varieties in Nigeria

PurposeThe objective of this study is to ascertain the effect of cooking and soaking on the physical characteristics, nutrient composition and sensory evaluation of an indigenous “ofada” rice and a foreign “aroso” rice varieties in Nigeria.Design/methodology/approachThe two rice varieties were freshly purchased in the raw state, soaked in water and cooked. The physical characteristics, such as length, width, weight, colour, purity, breakage, cooking time, dispersability and swelling capacity of the raw rice varieties were determined according to official methods. The raw, soaked and cooked rice varieties were oven‐dried at 60○C for 4 h and milled to obtain a uniform surface area. The proximate composition and some minerals of the raw, soaked and cooked rice varieties and the sensory evaluation of the cooked rice were determined. Findings–The physical characteristics showed that “ofada” and “aroso” rice varieties were brown and creamy in colour, respectively. There were significant (p<0.01) differences in the purity, breakage, cooking time, swelling capacity and weight of the whole grain, but no difference in the length and width. The raw, cooked and soaked “ofada” rice contain more protein, fat, and fibre, than in “aroso” rice, but with no change in carbohydrate content. There were no significant (p>0.01) differences in the levels of minerals, Ca, Fe, Mg and P, in raw, cooked and soaked “ofada” and “aroso” rice. Sensory evaluation showed that cooked aroso rice was generally preferred, in terms of colour, aroma, taste, texture and overall acceptability.Originality/valueThe methods employed in this study are very simple and the two rice varieties are readily available, acceptable to local tastes and widely consumed in Nigeria. The local or indigenous “ofada” rice is compared favourably with a foreign and imported parboiled “aroso” rice. It is therefore possible for small scale and cottage industries to embark on commercial production and fortification of the local rice varieties in Nigeria.

Changes in carbohydrate contents in shoot tips, leaves and roots of strawberry ( Fragaria × ananassa Duch.) during flower-bud differentiation

Flowering is an important step in crop production. Under flower-inducing conditions, biochemical or physiological changes can be recognized. Changes in carbohydrates have an important role in flower development in plants; however, carbohydrate changes during flower bud differentiation in strawberry have not been thoroughly investigated. In this study, runner plants potted in 18 cm diameter pots and grown under non-inducing conditions (28 ± 3/22 ± 3 °C day/night; 16 h day length). When the plants were established, half of the plants then were put under inducing conditions (23 ± 3/13 ± 3 °C day/night; 8 h day length). After the induction period of 21 short-day cycles, plants were brought to non-inductive conditions again. In order to evaluate the carbohydrate changes during flower differentiation, shoot tips, leaves and roots were sampled from four replicated plants collected weekly for the period of 7 weeks. Sucrose, glucose and fructose contents were determined by HPLC, and starch by the anthrone method. The results obtained indicated that the most abundant soluble sugar in all organs tested was sucrose. Sucrose in the shoot tips of induced plants at 42, 56 and 70 days after the start of the short-day treatment were significantly higher than corresponding time in non-induced plants. However, the glucose, fructose and starch contents in shoot tips, leaves and roots of non-induced plants in most sampling dates were greater than those of induced plants. In other words, the shoot tips (bud) of induced plants acted as strong ‘utilizing sink’ and preferentially metabolized carbohydrates rather than storing them. It seems that non-structural carbohydrate contents in shoot tips, leaves and roots of strawberry may have an important role in flower-bud differentiation.

Effect of cooking and soaking on physical characteristics, nutrient composition and sensory evaluation of indigenous and foreign rice varieties in Nigeria

The objective of this study is to ascertain the effect of cooking and soaking on the physical characteristics, nutrient composition and sensory evaluation of indigenous ‘ofada’ rice and foreign ‘aroso’ rice varieties in Nigeria. The two rice varieties were freshly purchased in the raw state, soaked in water and cooked. The physical characteristics, such as, length, width, weight, colour, purity, breakage, cooking time, dispersability and swelling capacity of the raw rice varieties were determined. The raw, soaked and cooked rice varieties were oven dried as 60°C for 4 h and milled to attain uniform surface area. The proximate composition and some minerals of the raw, soaked and cooked rice varieties and the sensory evaluation of the cooked rice were determined. Ofada and aroso rice varieties were brown and creamy in colour, respectively. There were significant (p length and width. The raw, cooked and soaked ofada rice contain more protein, fat, and fibre than in aroso rice, but with no change in carbohydrate content .There were no significant (p>0.01) differences in the levels of minerals; Ca, Fe, Mg and P, in raw, cooked and soaked ofada and aroso rice. Sensory evaluation showed that cooked aroso rice was generally preferred, in terms of colour, aroma, taste, texture and overall acceptability.

Analysis of the Surfaces of Wood Tissues and Pulp Fibers Using Carbohydrate-Binding Modules Specific for Crystalline Cellulose and Mannan

Carbohydrate binding modules (CBMs) are noncatalytic substrate binding domains of many enzymes involved in carbohydrate metabolism. Here we used fluorescent labeled recombinant CBMs specific for crystalline cellulose (CBM1(HjCel7A)) and mannans (CBM27(TmMan5) and CBM35(CjMan5C)) to analyze the complex surfaces of wood tissues and pulp fibers. The crystalline cellulose CBM1(HjCel7A) was found as a reliable marker of both bacterially produced and plant G-layer cellulose, and labeling of spruce pulp fibers with CBM1(HjCel7A) revealed a signal that increased with degree of fiber damage. The mannan-specific CBM27(TmMan5) and CBM35(CjMan5C) CBMs were found to be more specific reagents than a monoclonal antibody specific for (1-->4)-beta-mannan/galacto-(1-->4)-beta-mannan for mapping carbohydrates on native substrates. We have developed a quantitative fluorometric method for analysis of crystalline cellulose accumulation on fiber surfaces and shown a quantitative difference in crystalline cellulose binding sites in differently processed pulp fibers. Our results indicated that CBMs provide useful, novel tools for monitoring changes in carbohydrate content of nonuniform substrate surfaces, for example, during wood or pulping processes and possibly fiber biosynthesis.

Changes in carbohydrate contents of Zantedeschia leaves under gibberellin-stimulated flowering

The effect of gibberellic acid (GA3) on the carbohydrate accumulation in relation to vegetative growth of Zantedeschia ‘Black Magic’ plants undergoing transition to flowering was investigated. In response to GA treatment the carbohydrate level increased independently of earlier stimulation of shoot emergence. Under vegetative growth stage the content of reducing sugars of leaf blades was 2.5-fold higher than in control plants, and suggests the stimulation of photosynthetic activity. The changes observed during the flowering, in principle noted in petiole tissues, support the GA-effect on assimilate transport to the sink organs. Moreover, the high level of non-structural carbohydrates in petiole tissues, in particular reducing sugars, can be an effect of photosynthetic activity of these organs and/or essential for osmoregulation and high turgor pressure. The results indicate that apart from the influence on the shoot emergence, the GAs may stimulate the photosynthetic activity from the beginning of shoot growth and are thus responsible for the enhancement of callas flower yield.

Changes in Carbohydrate Content and Gene Expression During Tuberous Root Development of Sweet Potato

To understand the carbohydrate metabolism during the developmental process of tuberous roots in sweet potato (Ipomoea batatas), changes in carbohydrate content of the tuberous roots and expression of three genes, encoding granule-bound starch synthase, sporamin and β-amylase responsible for the synthesis of two major abundant components, starch and protein, were examined during different stages of tuberization. Results showed that the expression of genes, starch and sucrose content were highly correlated with the size of tuberous roots suggesting that fresh weight should be more suitable than growing-day to serve as an indicator for defining developmental stages. Increase in sucrose concentration during development might play an important role in starch accumulation; not only it functions as a substrate for starch synthesis but it can also stimulate the transcription of granule-bound starch synthase gene.

Changes in Carbohydrate Content and the Activities of Acid Invertase, Sucrose Synthase and Sucrose Phosphate Synthase in Vegetable Soybean During Fruit Development

Changes in Carbohydrate Content and the Activities of Acid Invertase, Sucrose Synthase and Sucrose Phosphate Synthase in Vegetable Soybean During Fruit Development

Changes in Carbohydrate Content during Wheat Maturation—What is Measured by near Infrared Spectroscopy?

The role of bread, pasta and related products produced from milled wheat seeds is important to the human diet, so monitoring changes of starch content in developing grain is essential. Immature wheat grains are also used as a functional food, particularly as a source of water-soluble carbohydrates. The amount and variation in content of different carbohydrates changes considerably during maturation and these changes were non-destructively monitored in developing grain using near infrared (NIR) spectroscopy. Characteristic changes in three carbohydrate absorption bands [1585–1595 nm (Carbohydrate I), 2270–2280 nm (Carbohydrate II) and 2325–2335 nm (Carbohydrate III)] were identified and it was concluded that the different dynamics of carbohydrates (starch accumulation as well as synthesis/decomposition of water-soluble carbohydrates) could be followed sensitively by monitoring these three different regions of NIR spectra. Carbohydrate I represents the effect of starch accumulation during maturation based on the vibrations of intermolecular hydrogen bonded O–H groups in polysaccharides. Carbohydrate II is the manifestation of O–H stretching and C–C stretching vibrations existing unengaged in water-soluble carbohydrates while Carbohydrate III describes the changes in C–H stretching and deformation band of poly- and mono-oligosaccharides. NIR spectroscopic techniques are shown to be effective in monitoring plant physiological processes and the spectra have hidden information for predicting the stage of growth in wheat seed.

Osmotic stress changes carbohydrate partitioning and fructose-2,6-bisphosphate metabolism in barley leaves.

Carbohydrate metabolism was investigated in barley leaves subjected to drought or osmotic stress induced by sorbitol incubation. Both drought and osmotic stress resulted in accumulation of hexoses, depletion of sucrose and starch, and 5-10-fold increase in the level of the regulatory metabolite fructose-2,6-bisphosphate (Fru-2,6-P2). These changes were paralleled by an increased activity ratio of fructose-6-phosphate,2-kinase / fructose-2,6-bisphosphatase (F2KP). The drought-induced changes in carbohydrate content and Fru-2,6-P2 metabolism were reversed upon re-watering. This reveals a reversible mechanism for modification of the F2KP enzyme activity. This suggests that F2KP might be involved in altering carbohydrate metabolism during osmotic stress. However, labelling with [14C]-CO2 showed that sucrose synthesis was not inhibited, despite the increased Fru-2,6-P2 levels, and demonstrated that increased flux into the hexose pools probably derived from sucrose hydrolysis. Similar effects of osmotic stress were observed in leaf sections incubated in the dark, showing that the changes did not result from altered rates of photosynthesis. Metabolism of [14C]-sucrose in the dark also revealed increased flux into hexoses and reduced flux into starch in response to osmotic stress. The activities of a range of enzymes catalysing reactions of carbohydrate metabolism in general showed only a marginal decrease during osmotic stress. Therefore, the observed changes in metabolic flux do not rely on a change in the activity of the analysed enzymes. Fructose-2,6-bisphosphate metabolism responds strongly to drought stress and this response involves modification of the F2KP activity. However, the data also suggests that the sugar accumulation observed during osmotic stress is mainly regulated by another, as yet unidentified mechanism.

Changes in carbohydrate content and related enzyme activity during Cyphomandra betacea (Cav.) Sendtn. fruit maturation

Changes in sugar content and activities of invertase (EC 3.2.1.26) and sucrose synthase (EC 2.4.1.13) were measured throughout fruit development in tree tomato (Cyphomandra betacea (Cav.) Sendtn.). Fruit of C. betacea accumulated predominantly reducing sugars similar to Lycopersicon esculentum and in contrast to sucrose accumulation, which is characteristic of L. peruvianum. Soluble acid invertase, fructose and glucose were localized principally in the vacuole. The soluble acid invertase activity was highest in ripe fruit (80 days past anthesis), while sucrose synthase activity was highest in the young fruit and declined with development. Otherwise, the activity of cell wall-bound acid invertase was less and may be greatly decreased by interaction with an invertase inhibitor protein, located in the cell walls of C. betacea fruit. The highest soluble acid invertase activity was associated with fruit ripening and during early stage of development. Sucrose synthase is the dominant enzyme in metabolizing imported sucrose.

Changes in Carbohydrate Content and Activities of Acid Invertase, Sucrose Synthase and Sucrose Phosphate Synthase in Broccoli During Short Term Storage at Low Temperature

Changes in Carbohydrate Content and Activities of Acid Invertase, Sucrose Synthase and Sucrose Phosphate Synthase in Broccoli During Short Term Storage at Low Temperature

Physiological responses of cabbage plug seedlings to water stress during low-temperature storage in darkness

Seedling storage is needed for coordinating the supply of seedlings with variable demand. In order to develop a handling method for storing seedlings, the effects of water stress on shoot growth, water potential, and carbohydrate contents during storage, and on the photosynthetic and transpiration rates of cabbage seedlings after removal from storage were investigated. Seedlings were stressed by withholding of watering for 1 day before storage, and were then stored for 6 days at 10 °C in darkness. Water stress reduced the leaf water potential of the stored plants. Shoots of control plants etiolated, whereas those of stressed plants remained almost unchanged. The starch content in shoots decreased in both treatments, but the decrease was smaller in stressed plants than in unstressed plants. Water stress increased contents of glucose and fructose in shoots and of glucose and sucrose in roots. After removal from storage and transplanting, the stressed plants showed a steadier return to photosynthesis and transpiration than control plants. These results suggest that water stress and the accompanying changes in carbohydrate contents, suppresses shoot elongation during storage and improves the recovery of seedlings after removal from storage.

Cold acclimation and abscisic acid induced alterations in carbohydrate content in calli of wheat genotypes differing in frost tolerance

The effect of cold and abscisic acid (ABA) treatment on soluble carbohydrate content was compared in callus cultures of wheat genotypes differing in frost tolerance. The effect of 5A chromosome substituted from the frost tolerant <<Cheyenne>> to the sensitive <<Chinese Spring>> on cold-induced carbohydrate accumulation was also determined. Following cold hardening, the increase in sucrose and fructan level in calli of tolerant varieties was significantly higher than those of the sensitive ones. In 5A substitution line higher sucrose and fructan content was detected than in recipient <<Chinese Spring>>. Tendentiously, cold stress caused higher degree of changes in carbohydrate content than the exogenously applied ABA did. Comparing the accumulation pattern of the components of WSC measured in vitro to the previously published in vivo results it can be concluded that in the case of sucrose and fructans it was similar, while for the reducing sugars it was different. The regulatory role of chromosome 5A either in the development of freezing tolerance or carbohydrate accumulation was confirmed in dedifferentiated calli, as well.

Effects of desiccation on the physiology and biochemistry of Quercus alba acorns.

Seeds that lose viability when dried to a water content of less than 12% are said to be recalcitrant. We subjected acorns of Quercus alba L., a species with recalcitrant seeds, to desiccation to determine the effects of drying on lipids, proteins and carbohydrates of the embryonic axis and cotyledon tissues. Samples of fresh seed and seed dried for selected intervals were analyzed for water content and germination, and for lipids, proteins and carbohydrates by Fourier transform-infrared (FT-IR) spectroscopy. Carbohydrates were further analyzed by gas chromatography (GC). The FT-IR analysis revealed that membrane lipid structure initially exhibited reversible shifts between gel and liquid crystalline phases in response to drying and rehydration; however, reversibility declined as viability was lost. Changes in carbohydrate concentration were observed based on peak height comparisons; sucrose concentration in the embryonic axis increased dramatically after 5 days of drying. The most sensitive indicator of desiccation damage was the irreversible change in protein secondary structure in embryonic axes and cotyledon tissue. These changes were illustrated by shifts in amide absorbance near 1650 cm(-1). Gas chromatography indicated an abundance of sucrose in both the embryonic axes and the cotyledon tissue. Although sucrose concentrations in these tissues were initially similar, sucrose concentration in the embryonic axes became significantly greater than in the cotyledons as the acorns dried. We hypothesize that, in drying acorns, increased concentration of sucrose does not prevent loss of viability, but acts as a glycoprotectant against cell collapse and cell wall membrane damage as water stress increases.