Changes In Carbohydrate Content Research Articles

The effect of heat stress on tomato pollen characteristics is associated with changes in carbohydrate concentration in the developing anthers.

Continuous exposure of tomato 'Trust' to high temperatures (day/night temperatures of 32/26 degrees C) markedly reduced the number of pollen grains per flower and decreased viability. The effect of heat stress on pollen viability was associated with alterations in carbohydrate metabolism in various parts of the anther during its development. Under control, favourable temperature conditions (28/22 degrees C), starch accumulated in the pollen grains, where it reached a maximum value 3 d before anthesis; it then diminished towards anthesis. During anther development, the concentration of total soluble sugars gradually increased in the anther walls and in the pollen grains (but not in the locular fluid), reaching a maximum at anthesis. Continuous exposure of the plants to high temperatures (32/26 degrees C) prevented the transient increase in starch concentration and led to decreases in the concentrations of soluble sugars in the anther walls and the pollen grains. In the locular fluid, however, a higher soluble sugar concentration was detected under the high-temperature regime throughout anther development. These results suggest that a major effect of heat stress on pollen development is a decrease in starch concentration 3 d before anthesis, which results in a decreased sugar concentration in the mature pollen grains. These events possibly contribute to the decreased pollen viability in tomato.

Elevated ozone (O 3) alters carbohydrate metabolism during grain filling in wheat ( Triticum aestivum L.)

In Swedish open-top chamber experiment, field-grown spring wheat ( Triticum aestivum L. cv. Dragon) was exposed to ozone in 1995 and 1997 to determine the effect of ozone on non-structural carbohydrate concentrations in different plant organs. In both 1995 and 1997, the plants were exposed to an ozone AOT40 dose of approximately 2500 nmol mol −1 h during and after anthesis (NF1+), with non-filtered air (NF) alone as a control. In 1995, there was also a treatment with a similar AOT40 dose (2500 nmol mol −1 h) administered before (NF1+ pre-treatment) anthesis. In 1997, treatments with AOT40 doses of 0 (CF), 6321 (NF2+) and 10 900 nmol mol −1 h (NF3+) during and after anthesis were additionally used. In both years, the concentrations of non-structural carbohydrates were determined several times during plant development to detect ozone-induced changes in carbohydrate metabolism. In 1995, ozone exposure during and after anthesis (NF1+) reduced significantly post-anthesis leaf and stem carbohydrate concentrations, indicating accelerated senescence of the plants. In 1997, the flag leaves of plants of the NF3+ treatment contained significantly more water soluble carbohydrates (WSC) and total non-structural carbohydrates (TNC) than the flag leaves of the other treatments at anthesis and 2 weeks after anthesis. Evidently, this indicates disturbed export of assimilates from the flag leaves of the NF3+ treatment. Lower ozone doses (NF2+ and NF1+) had a non-significant effect on leaf carbohydrates. The stems of wheat plants exposed to elevated ozone contained significantly less carbohydrates than the stems of CF and NF plants 2 and 4 weeks after anthesis. Ear/grain starch and TNC concentrations (i.e. grain quality in terms of carbohydrates) were less affected by ozone exposure compared with the parameters related directly to grain growth and yield, such as the TNC amount in 1000 grains. It is concluded that most of the ozone-induced changes in carbohydrate concentrations were associated with accelerated leaf and plant senescence.

Effects of lifting date and storage time on changes in carbohydrate content and photosynthetic efficiency in three deciduous species

SummaryThe effect of lifting date and storage duration on the change in carbohydrate reserves during cold storage and the photosynthetic capacity after storage was examined in red-osier dogwood, common oak and silver birch of two genotypes ‘Asarum’ and ‘Halstenbeck’. Plants were grown at a ®eld site in southern Sweden and were lifted on two dates, 21 September and 30 November 1998. Plants were packed in closed plastic bags and kept in cold storage. Carbohydrate reserves were measured at lifting and after 8, 16 and 24 weeks of storage. Plants were removed from storage after 8, 12, 16, 20 and 24 weeks and were subsequently grown in a climate chamber. After four weeks, plants were assessed for mortality, die-back, growth and photosynthetic capacity, measured as chlorophyll fluorescence. Chlorophyll fluorescence indicated that lifting per se is a strong stress factor, as plants, independently of lifting date and storage duration, were stressed and had low photochemical efficiency in photosystem II. Further, the low efficiency was more pronounced in plants lifted early. Die-back appeared in early lifted plants of all species after 3–4 months of storage, except for silver birch ‘Asarum’. Carbohydrates in roots and shoots declined during storage in early lifted plants, but only in late lifted plants of roots and shoots of red-osier dogwood and shoots of common oak. Shoot growth decreased in early lifted red-osier dogwood plants, with longer storage. This study has shown that lifting date and storage duration are two strong stress factors, which have a detrimental effect on plant vitality, even if plants are stored in closed plastic bags.

Influence of food quality and quantity on the growth and development of Crassostrea gigas larvae: a modeling approach

A biochemically based model was developed to simulate the growth, development and metamorphosis of larvae of the Pacific oyster, Crassostrea gigas. The model is unique in that it (1) defines larvae in terms of their protein, neutral lipid, polar lipid, carbohydrate and ash content; (2) tracks weight separately from length to follow larval condition index and (3) includes genetic variation in growth efficiency and egg quality to better simulate cohort population dynamics. The model includes parameterizations for larval filtration, ingestion and respiration that determine growth rate and processes controlling larval mortality and metamorphosis. Changes in tissue composition occur as the larva grows and in response to the biochemical composition of the food. The simulations show that genetically determined variations in growth efficiency produce significant changes in larval survival and success at metamorphosis. Larvae with low growth efficiency are successful under a much narrower range of culture conditions than larvae with high growth efficiency. The impact of low growth efficiency is primarily controlled by the ability of larvae to store lipid for metamorphosis. Culture conditions that provide increased dietary lipid counterweigh low growth efficiency. Changes in food quantity and quality had little effect on size at metamorphosis. On the other hand, larval life span and success rate at metamorphosis varied over a wide range depending upon the conditions of the simulation. Food quality and food availability both influence larval life span and, hence, larval survival. As ingestion rate decreases, larval life span increases and cohort survival declines. Increased lipid or decreased protein in the diet improves cohort survival. Changes in carbohydrate content are less influential. If cohort success is significantly affected by mortality during larval life rather than success at metamorphosis, the influence of food quality becomes more complex. The range of food compositions yielding high survival is restricted by a balance between improved success at metamorphosis obtained by increased lipid storage and the shortening of larval life span as a result of more rapid growth, a function of protein availability. These simulations illustrate the strength and utility of numerical models for evaluating and designing hatchery protocols for optimizing yield of C. gigas larvae.

Photosynthetic capacity is differentially affected by reductions in sedoheptulose-1,7-bisphosphatase activity during leaf development in transgenic tobacco plants.

The impact of reduced sedoheptulose-1,7-bisphosphatase (SBPase) activity on photosynthetic capacity and carbohydrate status was examined during leaf expansion and maturation in antisense transgenic tobacco (Nicotiana tabacum L. cv Samsun) plants. In wild-type plants, photosynthetic capacity was lowest in young expanding leaves and reached a maximum in the fully expanded, mature leaves. In contrast, the transgenic antisense SBPase plants had the highest photosynthetic rates in the young expanding leaves and lowest rates in the mature leaves. In the mature, fully expanded leaves of the transgenic plants photosynthetic capacity was closely correlated with the level of SBPase activity. However, in the youngest leaves of the SBPase antisense plants, photosynthetic rates were close to, or higher than, those observed in wild-type plants, despite having a lower SBPase activity than the equivalent wild-type leaves. Reductions in SBPase activity affected carbohydrate levels in both the mature and young developing leaves. The overall trend was for decreased SBPase activity to lead to reductions in carbohydrate levels, particularly in starch. However, these changes in carbohydrate content were also dependent on the developmental status of the leaf. For example, in young expanding leaves of plants with the smallest reductions in SBPase activity, the levels of starch were higher than in wild-type plants. These data suggest that the source status of the mature leaves is an important determinant of photosynthetic development.

DEVELOPMENTAL CHANGES IN CARBOHYDRATE CONTENT IN YOUNG ROSE SHOOTS (Rosa hybrida ‘FRISCO’)

Changes of carbohydrate content of a developing rose shoot, submitted to different day-night temperature conditions were investigated. Two successive experiments were set up in four glasshouse compartments with young rose plants (Rosa hybrida 'Frisco'). The plants were submitted to four day/night temperature regimes (19.3/12 degreesC, 18/16 degreesC, 17.5/17.5 degreesC and 16/22 degreesC) maintaining a daily mean temperature of 17.5 degreesC. The plants were grown under a photoperiod of 18 hours. The experiment started at decapitation and ended when all shoots were harvested. The light integral was 148 MJ/m(2) for the first experiment and 307 MJ/m2 for the second experiment. Carbohydrate measurements (glucose, fructose, sucrose and starch) were performed on the entire uppermost shoots, source leaves and sink tissue. Four different developmental stages of the shoot bud were analysed: stage 1 - vegetative bud, stage 4 - petal differentiation, stage 5/6 - pistil and stamen differentiation and a harvestable flower stem. The results show that both developmental stages and light intensity have a strong impact on the carbohydrate level of the shoot and source leaf while temperature regime has no direct effect.

Changes in Carbohydrate Concentrations in Basal Leaf Sheaths of Allium × wakegi Araki in Relation to Bulb Development and Dormancy

Changes in carbohydrate concentrations in basal leaf sheaths (this part corresponds to a bulb after bulb development) of two Allium × wakegi Araki cultivars, 'Kiharabansei No.1'(dormant type) and 'Ginoza'(nondormant type) during bulb development and postharvest storage were investigated. There was little difference in the fructose, glucose, sucrose, and fructans concentrations throughout the experimental period between 'Kiharabansei No.1' and 'Ginoza'. Hence, only changes in the former are discussed. During bulb development, when plants of 'Kiharabansei No.1' became dormant, the concentrations of fructose and glucose decreased, while those of fructans and total carbohydrates increased ; there were no significant changes in sucrose concentrations. During postharvest storage of 'Kiharabansei No.1' bulbs, they were gradually released from dormancy and the concentrations of all the components remained constant. The percentage of fructans to total carbohydrates after bulb development exceeded 90% (w/w). This accumulation of fructans was specific to basal leaf sheaths. When bulbs of 'Kiharabansei No.1' planted in moist vermiculite began to sprout, the concentrations of fructose and glucose in the bulbs increased, while those of fructans and total carbohydrates decreased.

Comparing carbohydrate status during norway spruce seed development and somatic embryo formation

The carbohydrate status of developing seeds of Picea abies was examined in order to provide a frame of reference for the evaluation of changes in carbohydrate content in maturing somatic embryos of the same species. Samples were taken at weekly intervals from 12 May 1998 (estimated time of pollination) until 20 October 1998. The total non-structural carbohydrate content was high (≈150–180 μg mg−1 dry weight) at the time of the first samples and the carbohydrate spectrum consisted of sucrose, glucose, fructose, and pinitol. A dramatic decrease in carbohydrate content took place from June 6 onwards, that was accompanied by changes in carbohydrate partitioning to favor sucrose over hexoses and the disappearance of pinitol. Raffinose and stachyose were first detected on July 28, and their content gradually increased thereafter. Isolated embryos and remaining megagametophytes were analyzed starting with September 1. Carbohydrate content was higher in isolated zygotic embryo than in the rest of the seed, with a slowly increasing fraction of raffinose and stachyose. Comparisons of presented data with the results of our previous study of somatic embryo carbohydrate status (Lipavska et al., 2000) revealed the following common features: (1) a decrease in total carbohydrate content and (2) an increase in sucrose:hexose ratios in developing seeds and embryonal suspensor mass. Marked differences were observed in carbohydrate spectra: (1) somatic embryo development was not accompanied by pinitol accumulation in any phase; (2) mature zygotic embryos, in contrast to mature somatic embryos, contained raffinose and stachyose. These observations will provide a solid basis for improvement of protocols for somatic embryogenesis in Picea.

Root growth inhibition by low temperature explains differences in sugar accumulation between spring and winter wheat

Exposure to low temperatures is associated with an increased concentration of carbohydrate (mainly sugar) in tissues of cool temperate species. Within a species, carbohydrate concentration is usually much higher in winter cultivars than in spring ones, frequently correlates well with winter survival, and is also related to the expression of several genes. It has been proposed that either a smaller reduction in carbon assimilation, or greater growth inhibition by cold in winter cultivars, might explain this differential increase in carbohydrate concentration. However, little experimental support for these hypotheses is available. In this work, carbon assimilation and growth, as related to the cold-induced increase in carbohydrate concentration, are analysed in contrasting wheat (Triticum aestivum L.) genotypes. No significant differences in the degree of cold-induced reduction of carbon assimilation between cultivar types were found. Also, shoot growth was similarly inhibited by cold in both winter and spring cultivars. However, root growth rates were lower in cold-treated winter cultivars than in spring ones, which led to much larger root systems in the latter. A simple method for quantitatively estimating the contribution of cold-induced changes in carbon fixation and growth to changes in carbohydrate concentration was developed. This analytical framework suggests that the degree of root growth inhibition by cold was the main factor in determining differences in carbohydrate content between cultivars.

Changes in Carbohydrate Content and the Activities of Acid invertase, Sucrose Synthase and Sucrose Phosphate Synthase in Asparagus Spears During Storage

Changes in Carbohydrate Content and the Activities of Acid invertase, Sucrose Synthase and Sucrose Phosphate Synthase in Asparagus Spears During Storage

Effects of temperature and stem length on changes in carbohydrate content in summer-grown cut chrysanthemums during development and senescence

Abstract Changes in the carbohydrate content in capitula, stems, and leaves were investigated in cut chrysanthemum Dendranthema×grandiflorum (Ramat.) Kitamura ‘Seiun’ plants with 60-cm stems held at 20, 25 and 30°C for 27 days postharvest. In addition, plants with 20-cm stems were studied at 25°C. Diameter of the capitula, the angle of the florets, fresh weight (FW) and dry weight (DW) increased more slowly at 30°C/60 cm and 25°C/20 cm than at 20°C/60 cm and 25°C/60 cm. The number of well-developed florets was notably smaller, and the number of tubular-shaped florets was larger at 30°C/60 cm than at 20°C/60 cm. Glucose and fructose concentrations in the capitula increased, although they decreased midway through treatment at 30°C/60 cm. Fructose concentrations in the stems, and in particular in the middle stems, were greater at 30°C/60 cm than at 20°C/60 cm and 25°C/60 cm. The increase in the total DW during treatments suggested that photosynthesis was occurring in the leaves and that photosynthates were a main source for the capitula and stems. Development of the capitula was suppressed, which was related to the reduction in its carbohydrate supply. Wilting of petals was not accelerated at high temperatures and with short-stem treatments.

Silverleaf whitefly stress impairs sugar export from cotton source leaves

Silverleaf whitefly (SLW), Bemisia argentifolii Bellows and Perring, is one of the most noxious pests of numerous field and vegetable crops, causing billions of dollars worth of damage throughout the world. SLW is a phloem feeder whose feeding is likely to interfere with phloem transport. The aim of this study was to test the hypothesis that SLW infestation impairs carbohydrate export from source leaves, and consequently increases their carbohydrate content. The youngest fully expanded leaves of cotton (Gossypium hirsutum L., cv. Siv'on), grown under SLW‐infested and noninfested conditions, were characterized for their diurnal changes in carbohydrate content and photoassimilate export. SLW infestation induced a considerable reduction in net photosynthetic rate (Pn), coupled with increased sucrose, glucose and fructose and decreased starch concentrations. Export rate was determined after CO2 pulse‐labeling both by in situ monitoring of leaf radioactivity and by analyzing the content and radioactivity of the major carbon metabolites. Radioactive counting indicated a lower rate of C efflux for the infested plants. A similar trend was found for the specific activities of sucrose and the three soluble sugars combined (sucrose, glucose and fructose). A single exponential decay function with asymptote was fitted to the above efflux curves. All the calculated exponential coefficients demonstrated lower export rates after SLW injury. These results indicate that SLW impairs photoassimilate export, suggesting possible down‐regulation of Pn due to increased foliar soluble sugar contents.

622 Initiation of Flowering, Runner Formation, and Carbohydrate Distribution in Strawberry (Fragaria × ananassa Duch.) Mother and Daughter Plants Grown at Different Temperatures

The present research was undertaken to examine carbohydrate composition and distribution patterns and induction of flowering and runner formation in attached and detached strawberry plants grown under varying temperature conditions. There was an interaction between attached mother and daughter plants. Daughter plants affected flowering in mother plants, and mother plants influenced vegetative growth in daughter plants. Attachment and high temperature decreased root soluble carbohydrate concentration and promoted runner formation in both mother and daughter attached plants, suggesting that changes in carbohydrate concentration in the roots may be correlated with changes in vegetative growth. According to the results of this research, high temperatures are likely to enhance vegetative growth, whereas lower temperatures are likely to enhance the floral response. Differential temperature regimes applied to the mother/daughter plant experimental system could be an alternative to photoperiod treatments as a tool to study the correlation between environmental conditions and changes in vegetative and reproductive growth in strawberry.

Seasonal patterns of carbohydrate reserves in red spruce seedlings.

We studied seasonal dynamics of carbohydrate storage in red spruce (Picea rubens Sarg.) seedlings by measuring starch and sugar concentrations of old needles (>/= one year old), new needles (< one year old), stems, and roots in two stands in the Green Mountains of Vermont. Although the two stands differed in many site characteristics including percent slope, aspect, soil type, drainage, and 564 m in elevation, concentrations and seasonal patterns of carbohydrates were similar for the two stands. For all tissues, starch concentrations peaked in late spring, declined through summer, and reached a minimum in winter. Sugar concentrations were greater than starch concentrations in all months except May and June. Sugar concentrations peaked in winter, and old needles showed a significant increase in sugar concentration between February and March. This increase in sugar concentration occurred without any reduction in localized starch concentrations or reductions in sugar or starch concentrations in new needles, stems or roots. Because March measurements were made toward the end of a prolonged thaw, a time when increases in photosynthesis have been documented for red spruce, it is likely that the March increase in sugar concentrations resulted from photosynthesis during the thaw. Compared with stems and roots, needles generally contained the highest concentration of carbohydrates and exhibited the greatest seasonal change in carbohydrate concentration. Needles were also the largest reservoir of carbohydrates throughout the year, especially during winter. Because of the critical roles of needles in photosynthesis and storage of carbohydrates, we conclude that any factors that disrupt the accumulation or availability of carbohydrates in red spruce needles will greatly alter plant carbon relations.

Influence of in vitro growth conditions on photosynthetic competence and survival rate of Rehmannia glutinosa plantlets during acclimatization period.

The photosynthetic responses of Rehmannia glutinosa grown under photoautotrophic or heterotrophic conditions in vitro were investigated after transfer to greenhouse conditions. In addition, the changes in carbohydrate content and survival rates of the plantlets were evaluated. During six days after transplantation, the photosynthetic rate declined and photoinhibitory impairments represented by decrease of Fv/Fm and chlorophyll content were observed regardless of environmental conditions in vitro. Excessive transpiration was observed in plantlets grown under heterotrophic conditions during that period. Fructose and glucose content of the plantlets grown under photoautotrophic conditions increased with time and reached almost the same level of field grown plants after day 15. Under heterotrophic conditions, in contrast, the content of these sugars decreased continuously during that period. It is suggested that high survival rate of plantlets grown under photoautotrophic conditions has to be attributed to improvement of photosynthetic competence by imposed high light intensity and CO2 concentration in vitro. The results strongly suggest that the control of transpiration during early stage after transplantation plays a key role in the acclimatization process, and photoautotrophic conditions could be a solution to solve the problems associated with transplantation stress.

Diurnal Changes in Photosynthesis in Sugarcane Leaves: II. Enzyme activities and metabolite levels relating to sucrose and starch metabolism

SummaryDiurnal changes in carbohydrate contents, assimilate export, enzyme activities and metabolite levels associated with sucrose and starch synthesis in field-grown sugarcane (Saccharum sp. cv. NiF4) leaves were investigated during a natural 24 h day-night cycle. Eighty percent of the carbon fixed in sugarcane leaves at midday was exported immediately. Of the total carbon fixed during the day, 82% was exported in the daytime and 17% was accumulated as leaf starch which was exported at night. The activities of sucrose phosphate synthase (SPS), cytosolic fructose-1, 6-bisphosphatase (FBPase), UDP-glucose pyrophosphorylase (UDPG-PPase) and ADP-glucose pyrophosphorylase (ADPG-PPase), and the levels of triose phosphates (triose-P) and fructose-1,6-bisphosphate (FBP) showed distinct diurnal fluctuations during the day-night cycle. The levels of hexose phosphates fluctuated at smaller magnitudes compared with those in triose-P and FBP. The diurnal change in triose-P level was highly related to the changes in carbon exchange rate and sucrose content, while the sucrose content was closely related to the changes in activities of SPS, cytosolic FBPase and UDPG-PPase in leaves of sugarcane. The present results suggest that the availability of triose-P is a key factor in determining the rate of sucrose synthesis in sugarcane leaves.

Soil carbohydrates along a topoclimatic gradient in a Judean desert ecosystem

Soil carbohydrates, which include polysaccharides, are partly of microbial origin, contributing to soil structure and improving soil aggregates. This study examined the effect of climate along a topoclimatic gradient in the Judean desert. Soil was sampled at four locations representing different abiotic environments along the transect during the 1994 and 1995 study period. Significant differences in soil organic matter between the locations were obtained, decreasing towards the dry extreme desert sites. Carbohydrates, which probably are mainly composed of microbial extracellular polysaccharides, were found to increase during the dry season reaching maximum values by the end of autumn. The spatial and temporal changes in carbohydrate content are of great importance, representing biological activity that contributes to bonding between soil particles and helps promote nutrient accessibility to microorganisms. Copyright © 1999 John Wiley & Sons, Ltd.

Carbohydrate content and metabolism as related to maturity and chilling sensitivity of cv. Fortune mandarins.

Fruits of cv. Fortune mandarin were periodically harvested throughout the ripening period to evaluate changes in carbohydrate content and metabolism in flavedo tissue and to determine the potential role of carbohydrates in the tolerance of citrus fruit to chilling injury (CI). Sucrose showed little change in the flavedo during the season, but fructose and glucose increased, in nearly equal amounts, throughout the fall and winter, reaching a maximum in January. Starch levels were less abundant than soluble carbohydrates and rose continuously until March. Sucrose phosphate synthase (SPS; EC 4.1.14) activity decreased from December throughout ripening. Changes in sucrose synthase (SS; EC 2.4.1.13) and acid and alkaline invertase (Inv; EC 3.2.1.26) activities correlated with changes in the reducing sugars, but acid invertase was less active than the other sucrose-metabolizing enzymes. Carbohydrate changes in the flavedo of Fortune mandarins with fruit maturity appear not to be related to the chilling tolerance of fruits during cold storage.

Changes in Carbohydrate Content in Cut Chrysanthemum (Dendranthema*grandiflorum (Ramat.) Kitamura) 'Shuho-no-chikara' Stems Kept at Different Temperatures during Anthesis and Senescence.

Changes in carbohydrate content in capitulum, upper stems, middle stems, lower stems, upper leaves, and middle leaves in cut chrysanthemum stalks placed in vases at 20, 25 and 30°C were investigated for 3 weeks. The capitula showed no apparent senescence symptoms within 3 weeks at 20°C and 25°C, but senesced rapidly at 30°C. The leaves wilted earlier than did the capitula. Fructans were found at all plant parts, particularly, in the stems. During capitulum development, fructan content in the upper and middle stems rapidly declined to a low level which suggests that fructans in these stems were utilized for capitulum development. After the anthesis, leaves and stems seemed to serve as a carbohydrate source, but we could not elucidate whether the quantity of carbohydrates in the leaves and stems is related to the longevity of cut chrysanthemums.

Possible Roles of Soluble Carbohydrate Constituents in Cut Rose Flowers.

To investigate the role of soluble carbohydrates, particularly methyl glucoside, myo-inositol and xylose, cut 'Sonia' roses were continuously treated with distilled water (control) or a solution containing 30g·liter-1 sucrose and 200mg·liter-1 8-hydroxyquinoline sulfate (HQS). Changes in carbohydrate concentrations in different plants of the cut flowers were determined. This treatment extended the vase life of cut flowers and increased fresh weight of petals. Fructose, glucose, and sucrose were the main carbohydrates in petals, whereas the concentrations of others were lower at harvest. Although xylose concentration was very low at harvest, it increased with time ; the rest of the carbohydrates changed little with time. Fructose, glucose, and sucrose were the main carbohydrates in the remaining flower part, which were slightly affected by the treatment with sucrose plus HQS. Sucrose, fructose and methyl glucoside were main carbohydrates in the stem at harvest ; their concentrations in the control decreased with time but sucrose plus HQS suppressed this decrease. Sucrose was most abundant in leaves, followed by myo-inositol at harvest. The sucrose concentration in the control decreased sharply during first day after harvest but the treatment with sucrose plus HQS suppressed this decrease. On the contrary, the myo-inositol concentration was almost constant with time regardless of the treatment. Treatment with methyl glucoside and xylose markedly promoted flower bud opening, whereas myo-inositol did not. These results suggest that methyl glucoside and xylose are readily metabolized and contribute to flower opening in cut roses.