Influence of 2-deoxy-D-glucose upon growth and invertase activity of carrot (Daucus carota L.) cell suspension cultures

Carrot (Daucus carota L.) cell suspension cultures grew well when provided with glucose, fructose, sucrose or raffinose. Galactose and melibiose supported less growth unless supplemented with glucose or fructose. In combination with ten different sugar mixtures, 2-deoxy-D-glucose (dGlc) inhibited culture growth. Inhibitory effects of dGlc were more marked with fructose, melibiose, raffinose or mixtures of these sugars in the culture medium. The presence of glucose or galactose reduced the inhibitory effects of dGlc on culture growth. Experiments with radioactive labelled sugars demonstrated that dGLc uptake was greater in the presence of fructose than glucose, and that growth inhibition of dGlc coincided with its uptake. Reduced protein content was also associated with the inhibitory effects of dGlc. Cultured cells contained lower levels of invertase (EC 3.2.1.26) activity during the active phase of culture growth (up to 25 days after subculture) than when growth had peaked and subsequently declined. Acid and alkaline invertase activities were not greatly reduced by exogenous hexoses. Invertase activity was greatest during periods of low protein content in all cultures and was inhibited by dGlc during the latter phases of the culture period. Free intracellular sugars throughout the culture period consisted mainly of glucose and fructose.     

Vacuoles from Sugarcane Suspension Cultures : II. CHARACTERIZATION OF SUGAR UPTAKE

Vacuoles, isolated from sugarcane (Saccharum sp.) cells, took up 3-O methylglucose and sucrose and the evidence suggests specific transport systems for these sugars. There was no evidence of sugar efflux from preloaded vacuoles. Vacuoles in situ accumulated 3-O methylglucose, sucrose, glucose, and fructose, as shown by incubation of protoplasts with labeled sugar and subsequent analysis of vacuolar and cytoplasmic radio-activity. During the initial minutes of incubation, the amount and concentration of labeled sugar was higher in the cytoplasm than in the vacuole, but subsequently there was active uptake and accumulation into the vacuole. The rate of hexose transfer into the vacuole in situ approached that of hexose uptake by isolated vacuoles; however, the rate of sucrose uptake by isolated vacuoles was below the in situ rate. The site of sucrose synthesis was in the cytoplasm.     

Interconversion of free sugars in relation to activities of enzymes catalyzing synthesis and cleavage of sucrose in growing stem tissues of sorghum

Free sugar interconversion and activities of soluble acidic (pH 4.8) and neutral (pH 7.5) invertases, sucrose synthase (synthesis) and sucrose phosphate synthase were investigated in the growing nodes and internodes of sorghum (Sorghum vulgare). The results were substantiated with incorporation of 14C from supplied sucrose and hexoses into endogenous sugars of these stem tissues. With the advancement in plant growth, the content of total free sugars in apical nodes and internodes increased till 70 DAS (flowering stage) followed by a decline. In the corresponding basal tissues, the sugar build-up continued even beyond this stage of plant growth. Compared with basal stem tissues, the apical ones contained high activities of soluble invertases and a low proportion amongst free sugars of sucrose. The activities of sucrose-hydrolyzing enzymes were higher as compared with those of sucrose-synthesizing ones in both nodes and internodes and with the growth of plant, the activity of neutral invertase increased in these tissues. More 14C from supplied sucrose and hexoses appeared in extracted sugars from cut discs of apical nodes and internodes in comparison with their basal counterparts. 14C from supplied sucrose appeared in glucose, fructose and from supplied hexoses appeared in sucrose. The results suggest that in apical nodes and internodes, where a rapid cell division and cell expansion occur, sucrose is obligatorily inverted to meet the increased requirement of hexoses and there is a compartmentalized synthesis and cleavage of sucrose in the nodes and internodes of growing sorghum plant.     

Sucrose accumulation in developing peach fruit

Uptake of ¹⁴C-sugars and activities of sucrose metabolizing enzymes were determined in order to study the mechanism(s) of sucrose accumulation in developing peach fruit. Mesocarp of young peach fruit contained glucose and fructose but little sucrose. Starting 88 days after anthesis (DAA) the sucrose concentration increased greatly. The mechanism of sucrose accumulation was studied by measuring ¹⁴C-sucrose and ¹⁴C-glucose uptake rates at three different stages of fruit development, and by assaying weekly the activity of enzymes involved in the hydrolysis and/or synthesis of the soluble sugars. Uptake of 0.5–100 m M ¹⁴C-sucrose and ¹⁴C-glucose by mesocarp tissue slices showed a complex pattern at the first stage of fruit development (62 DAA). During the subsequent growth stages the pattern of sugar uptake changed and was approximately monophasic at the third stage of fruit development.
At 10 m M , glucose was taken up more rapidly than sucrose at the first and second stage of fruit development. Uptake was partially inhibited by the uncoupler carbonylcyanide m -chlorophenylhydrazone (CCCP) at 25 μ M. These results, together with the presence of a putative extracellular invertase, suggest an apoplastic route for sucrose uptake which is dependent, at least in part, on energy supply.
Activities of sucrose hydrolyzing enzymes (insoluble acid invertase, soluble acid invertase, neutral invertase, sucrose synthase) were high in young fruits and declined sharply with fruit development concomitantly with accumulation of sucrose. The storage of the sugar was not accompanied by a rise in synthetic activities (sucrose synthase, sucrose phosphate synthase), suggesting that sucrose could, at least in part enter the carbohydrate pool directly.     

宁夏枸杞果实糖积累和蔗糖代谢相关酶活性的关系

通过对枸杞果实发育过程中果实生长模式、蔗糖、果糖、葡萄糖和淀粉含量及糖代谢相关酶活性的测定,研究了宁夏枸杞果实生长发育过程中糖的代谢积累与相关酶活性的关系.结果表明:(1)宁夏枸杞果实发育呈双S"曲线,果实主要以积累己糖为主.(2)蔗糖磷酸合成酶(SPS)活性在果实发育初期处于下降的趋势,在花后19d开始上升,果实转色后又逐渐下降;蔗糖合成酶(SS)活性总体表现为SS分解方向的活性大于SS合成方向的活性,说明枸杞果实发育过程中,SS的活性主要以分解方向的为主;酸性转化酶(AI)和中性转化酶(NI)的活性随果实发育呈上升趋势,但在果实成熟后期有所下降,且AI和NI活性高于合成酶类的活性,较高的转化酶类活性促进了果实内部己糖的积累.(3)在枸杞果实生长发育中,葡萄糖和果糖含量与AI和NI均呈极显著正相关,而与其它酶不具有相关性.说明AI和NI在宁夏枸杞果实的糖代谢中起着主要的调控作用.     

套袋对梨果实发育过程中糖组分及其相关酶活性的影响

以翠冠和黄金梨为试材,测定套袋和未套袋(对照)梨果实发育时期果实中蔗糖、葡萄糖、果糖和山梨醇含量以及蔗糖代谢相关酶酸性转化酶(AI)、中性转化酶(NI)、蔗糖合成酶(SS)和蔗糖磷酸合成酶(SPS)的活性,并对果实中糖组分积累与酶活性的关系进行了分析.结果表明:(1)两梨品种套袋果实在发育过程中蔗糖、葡萄糖、果糖、山梨醇和糖代谢相关酶活性变化趋势与对照基本一致,套袋果实糖含量均低于对照但差异不显著,而各相关酶活性在两类果实间差异表现各异.(2)在梨果实发育早期,果实中以分解酶类为主,糖分积累低;发育后期以合成酶类为主,糖分积累多.(3)两品种套袋和对照果实AI活性与葡萄糖含量均呈显著或极显著正相关,SS合成方向活性与蔗糖含量均为极显著正相关,且翠冠对照果SPS活性与蔗糖含量呈极显著正相关.可见,套袋通过提高果实发育早期转化酶(Inv)活性,降低果实后期蔗糖磷酸合成酶(SPS)、蔗糖合成酶(SS)的活性来影响糖分积累,从而影响梨果品质.     

Pathway of Phloem unloading of sucrose in corn roots

The pathway of phloem unloading and the metabolism of translocated sucrose were determined in corn (Zea mays) seedling roots. Several lines of evidence show that exogenous sucrose, unlike translocated sucrose, is hydrolyzed in the apoplast prior to uptake into the root cortical cells. These include (a) presence of cell wall invertase activity which represents 20% of the total tissue activity; (b) similarity in uptake and metabolism of [¹⁴C]sucrose and [¹⁴C]hexoses; and (c) randomization of ¹⁴C within the hexose moieties of intracellular sucrose following accumulation of [¹⁴C] (fructosyl)sucrose. Conversely, translocated sucrose does not undergo apoplastic hydrolysis during unloading. Asymmetrically labeled sucrose ([¹⁴C](fructose)sucrose), translocated from the germinating kernels to the root, remained intact indicating a symplastic pathway for unloading. In addition, isolated root protoplasts and vacuoles were used to demonstrate that soluble invertase activity (V_max = 29 micromoles per milligram protein per hour, K_m = 4 millimolar) was located mainly in the vacuole, suggesting that translocated sucrose entered via the symplasm and was hydrolyzed at the vacuole prior to metabolism.     

Physiological Aspects of Sugar Exchange between the Gametophyte and the Sporophyte of Polytrichum formosum

The sporophyte of bryophytes is dependent on the gametophyte for its carbon nutrition. This is especially true of the sporophytes of Polytrichum species, and it was generally thought that sucrose was the main form of sugar for long distance transport in the leptom. In Polytrichum formosum, sucrose was the main soluble sugar of the sporophyte and gametophyte tissues, and the highest concentration (about 230 mm) was found in the haustorium. In contrast, sugars collected from the vaginula apoplast were mainly hexoses, with traces of sucrose and trehalose. p-Chloromercuribenzene sulfonate, a nonpermeant inhibitor of the cell wall invertase, strongly reduced the hexose to sucrose ratio. The highest cell wall invertase activity (pH 4.5) was located in the vaginula, whereas the highest activity of a soluble invertase (pH 7.0) was found in both the vaginula and the haustorium. Glucose uptake was carrier-mediated but only weakly dependent on the external pH and the transmembrane electrical gradient, in contrast to amino acid uptake (S. Renault, C. Despeghel-Caussin, J.L. Bonnemain, S. Delrot [1989] Plant Physiol 90: 913-920). Furthermore, addition of 5 or 50 mm glucose to the incubation medium induced a marginal depolarization of the transmembrane potential difference of the transfer cells and had no effect on the pH of this medium. Glucose was converted to sucrose after its absorption into the haustorium. These results demonstrate the noncontinuity of sucrose at the gametophyte/sporophyte interface. They suggest that its conversion to glucose and fructose at this interface, and the subsequent reconversion to sucrose after hexose absorption by haustorium cells, mainly governs sugar accumulation in this latter organ.     

Carbon-use efficiency in green sinks is increased when a blend of apoplastic fructose and glucose is available for uptake

Understanding how green sink strength is regulated in planta poses a difficult problem because non-structural carbohydrate (NSC) levels can have integrated, simultaneous feedback effects on photosynthesis, sugar uptake, and respiration that depend on specific NSC moieties. Photosynthetic gametophytes of the fern Ceratopteris richardii provide a simple land plant model to assess how different NSCs imported from the apoplast of intact plants affect green sink strength. Sink strength was quantified as the amount of exogenous sugar that plants grown in low light depleted from their liquid media, and the relative contributions of carbon assimilation by photosynthesis and sugar uptake was estimated from stable isotope analysis of plant dry mass. Gametophytes absorbed fructose and glucose with equal affinity when cultured on either hexose alone, or in the presence of an equimolar blend of both sugars. Plants also depleted sucrose from the surrounding media, although a portion of this disaccharide that was hydrolysed into fructose and glucose by putative cell wall invertase activity remained in the media. The δ(13)C in plant dry masses harvested from sugar treatments were all close to -18‰, indicating that 25-39% of total plant carbon was from C3 photosynthesis (δ(13)C=-29‰) and 61-75% was from uptake of exogenous sugars (δ(13)C=-11‰). Carbon-use efficiency (i.e. carbon accumulated/carbon depleted) was significantly improved when plants had a blend of exogenous sugars available compared with plants grown in a single hexose alone. Plants avoided complete down-regulation of photosynthesis even though a large excess of exogenous carbon fluxed through their cells.     

Differential Rates of Uptake of Glucose, Fructose and Sucrose by Pea Stem Protoplasts

Protoplasts from growing regions of etiolated pea stems takeup glucose more rapidly than fructose when supplied for briefperiods at low concentrations. The uptake of the two hexosesis differentially inhibited by galactoac and by reagents thatcurtail ATP synthesis, and uptake of one hexose is not preventedby the other, even at a 100-fold excess. Sucrose uptake is muchslower than that of either hexose and is correlated with theappearance of invertase activity in the medium. Label from [¹⁴C-glc]-sucroseis taken up more rapidly than from [¹⁴C-fru]-sucrose. It isconcluded that these cells take up supplied sucrose only afterhydrolysis to hexoses, which are then absorbed by differentcarrier-mediated processes. Key words: Glucose, fructose, invertase, pea, protoplast, sucrose     

Abnormal accumulation of sugars and phenolics in tobacco roots expressing the Agrobacterium T-6b oncogene and the role of these compounds in 6b-induced growth

The Agrobacterium T-DNA oncogene 6b induces tumors and modifies the growth of transgenic plants by an unknown mechanism. We have investigated changes in roots of tobacco seedlings that express a dexamethasone-inducible T-6b (dex-T-6b) gene. On induction medium with sucrose, intact or isolated dex-T-6b roots accumulated sucrose, glucose, and fructose and changed their growth, contrary to noninduced roots. Root fragments bridging agar blocks with or without sucrose accumulated sugars at the site of sucrose uptake, resulting in local growth. Induced root fragments showed enhanced uptake of 14C-labeled sucrose, glucose, and fructose. When seedlings were placed on sucrose-free induction medium, sugar levels strongly decreased in roots and increased in cotyledons. Collectively, these results demonstrate that 6b stimulates sugar uptake and retention with drastic effects on growth. Apart from sugars, phenolic compounds also have been found to accumulate in 6b tissues and have been proposed earlier to play a role in 6b-induced growth. Induced dex-T-6b roots accumulated high levels of 5-caffeoylquinic acid (or chlorogenic acid [CGA]), but only under conditions where endogenous sugars increased. Inhibition of phenylalanine ammonia-lyase with the competitive inhibitor 2-aminoindan-2-phosphonic acid (AIP) abolished CGA accumulation without modifying sugar accumulation or affecting the 6b phenotype. We conclude that the absorption, retention, and abnormal accumulation of sugars are essential factors in 6b-induced growth changes, whereas phenylpropanoids only marginally contribute to the 6b seedling phenotype.     

Carbohydrate utilisation by cell suspension cultures of Phaseolus vulgaris

Uptake of sugar by Phaseolus vulgaris cell suspension cultures from a sucrose supplemented medium is predominantly in the hexose form. This is due to a rapid cleavage of the sucrose by an apoplastic acid invertase activity and an apparent very low demand for and uptake of carbon from the medium prior to induction of cell growth and division. Glucose is preferentially taken up, leading to an accumulation of fructose in the medium. However, when the glucose is depleted the cells do take up the fructose at a rate similar to that of glucose. When glucose or fructose is supplied individually to cell cultures, both are utilised very efficiently with growth slightly better on the fructose medium. Hexose uptake is largely an active process with diffusion uptake even at the highest concentrations (> 50 m M ) contributing less than 30%. The hexose uptake system of the cells has a greater affinity for glucose (K_m= 240 µ M ) than for fructose (K_m= 960 µ M ) but the maximum uptake (V_max) is similar. The major difference in the kinetic properties of hexose uptake is that glucose is a strong inhibitor of fructose uptake, while fructose has little effect on glucose uptake. The differences in the kinetic properties of the uptake system for the two hexoses can largely explain the observed pattern of hexose utilisation when both glucose and fructose are present in the medium.     

Sugar retrieval by coats of developing seeds of Phaseolus vulgaris L. and Vicia faba L

Influxes of glucose, fructose and sucrose were characterised for coat cells of developing seeds of Phaseolus vulgaris L. and Vicia faba L. by monitoring uptake of [(14)C]sugars into excised seed-coat halves and two different protoplast populations derived from seed coats. Sugar influxes by the two populations of protoplasts were similar for each sugar species [sucrose > (fructose approximately glucose)] and hexoses competed with sucrose. Concentration-dependent influxes of all three sugars by excised seed coats could be described by a simple directly proportional relationship between concentration ([S]) and uptake rate (v) in the physiological range of sugar concentrations (v approximately A.[S]). Alternatively, with the exception of fructose influx by Vicia, all could be fitted to a Michaelis-Menten relationship, as could sucrose uptake by Vicia protoplasts. Apparent K(m) values were high ( approximately 100-500 mM) compared with those reported for other systems. Sucrose transport was distinct from glucose and fructose transport in both species. Sugar influx was decreased by p-chloromercuribenzenesulfonic acid, carbonylcyanide m-chlorophenylhydrazone and erythrosin B. These responses are consistent with sugar/H(+) symport acting to retrieve photoassimilates leaked to the apoplasm during post-sieve element transport within seed coats.     

Sugar uptake and starch biosynthesis by slices of developing maize endosperm

¹⁴C-Sugar uptake and incorporation into starch by slices of developing maize (Zea mays L.) endosperm were examined and compared with sugar uptake by maize endosperm-derived suspension cultures. Rates of sucrose, fructose, and d- and l-glucose uptake by slices were similar, whereas uptake rates for these sugars differed greatly in suspension cultures. Concentration dependence of sucrose, fructose, and d-glucose uptake was biphasic (consisting of linear plus saturable components) with suspension cultures but linear with slices. These and other differences suggest that endosperm slices are freely permeable to sugars. After diffusion into the slices, sugars were metabolized and incorporated into starch. Starch synthesis, but not sugar accumulation, was greatly reduced by 2.5 millimolar p-chloromercuribenzenesulfonic acid and 0.1 millimolar carbonyl cyanide m-chlorophenylhydrazone. Starch synthesis was dependent on kernel age and incubation temperature, but not on external pH (5 through 8). Competing sugars generally did not affect the distribution of ¹⁴C among the soluble sugars extracted from endosperm slices incubated in ¹⁴C-sugars. Competing hexoses reduced the incorporation of ¹⁴C into starch, but competing sucrose did not, suggesting that sucrose is not a necessary intermediate in starch biosynthesis. The bidirectional permeability of endosperm slices to sugars makes the characterization of sugar transport into endosperm slices impossible, however the model system is useful for experiments dealing with starch biosynthesis which occurs in the metabolically active tissue.     

Synthesis and Storage of Sucrose in Relation to Activities of Its Metabolizing Enzymes in Sugarcane Cultivars Differing in Maturity

Metabolic changes in the contents of sucrose and hexoses in relation to the activities of invertase, sucrose synthase and sucrose-phosphate synthase in early (CoJ 64) and late (Co 1148) maturing cultivars of sugarcane have been studied. During early stages of cane growth, lower activities of sucrose synthase and sucrose-phosphate synthase in leaf blade In CoJ 64 over Co 1148 were observed. However, sucrose content in sheath/blade was higher in CoJ 64 than in Co 1148. With the advancing age, the activity of soluble acid invertase (pH 5.4) in stem declined more rapidly in CoJ 64. This resulted in building up of high ratio of sucroselinvert sugars in stem tissue of this cultivar. Feeding uniformly-labelled sucrose and glucose to the cut discs of leaf sheath resulted in higher uptake of ¹⁴C in CoJ 64 than in Co 1148. Uptake by stem tissue discs of ¹⁴C from sucrose was less than that from hexoses. Based on these results, it is suggested that (i) the rapid fall in the activity of soluble acid invertase in stem concomitant with fast accumulation of sucrose in this tissue is an index of early maturity of the cane, and (ii) high content of sucrose in sheath is a reflection of an efficient translocation of this sugar in early maturing cultivars.     

Sugar uptake by maize endosperm suspension cultures

Maize (Zea mays L.) endosperm suspension cultures are a useful model system for studying biochemical and physiological events in developing maize endosperm. In this report, sugar uptake by the cultures is characterized. Uptake of ¹⁴C-labeled fructose and l-glucose was linear with time, while the rate of uptake of radioactivity from sucrose increased over a 120 min period. Both saturable and linear components of uptake were observed for fructose, glucose, sucrose, 1′-deoxy-1′-fluorosucrose, and maltose. Uptake of mannitol, sorbitol, and l-glucose took place at lower rates and was linear with concentration. Rates of incorporation of radioactivity from fructose and glucose exceeded that of sucrose at all concentrations tested. Kinetics of 1′-deoxy-1′-fluorosucrose uptake indicated that ¹⁴C from sucrose can be taken up by a saturable carrier of intact sucrose as well as by invertase hydrolysis and subsequent uptake of hexoses. Cell wall invertase was demonstrated histochemically. Further study of fructose uptake at a concentration at which the saturable component predominated revealed sensitivity to metabolic inhibitors, respiratory uncouplers, the nonpermeant sulfhydryl reagent p-chloromercuribenzenesulfonic acid, and nigericin. Uptake was not affected by valinomycin plus K⁺ and was stimulated by fusicoccin. Fructose and glucose uptake was not pH-sensitive below pH 7.0, whereas uptake of radioactivity from sucrose and 1′-deoxy-1′-fluorosucrose declined as the pH was increased above 5.0. Fructose uptake was not completely inhibited by glucose and vice versa, suggesting the presence of specific carriers. These results indicate that maize endosperm suspension cultures (a) absorb fructose via a typical, energy-requiring, carrier-mediated proton cotransport system; (b) possess saturable carriers for glucose and sucrose; and (c) also absorb sucrose via hexose uptake after sucrose hydrolysis by extracellular invertase.     

Accumulation of hexoses in leaf vacuoles: Studies with transgenic tobacco plants expressing yeast-derived invertase in the cytosol,vacuole or apoplasm

The subcellular distribution of hexoses, sucrose and amino acids among the stromal, cytosolic and vacuolar compartments was analysed by a nonaqueous fractionation technique in leaves of tobacco (Nicotiana tabaccum L.) wild-type and transgenic plants expressing a yeast-derived invertase in the cytosolic, vacuolar or apoplasmic compartment. In the wild-type plants the amino acids were found to be located in the stroma and in the cytosol, sucrose mainly in the cytosol and up to 98% of the hexoses in the vacuole. In the leaves of the various transformants, where the contents of hexoses were greater than in wild-type plants, again 97–98% of these hexoses were found in the vacuoles. It is concluded that leaf vacuoles contain transporters for the active uptake of glucose and fructose against a high concentration gradient. A comparison of estimated metabolite concentrations in the subcellular compartments of wild-type and transformant plants indicated that the decreased photosynthetic capacity of the transformants is not due to an osmotic effect on photosynthesis, as was shown earlier to be the case in transformed potato leaves, but is the result of a long-term dedifferentiation of tobacco leaf cells to heterotrophic cells.Abbreviations apo-inv tobacco plant with yeast invertase in the apoplasm - Chl chlorophyll - cy-inv tobacco plant with yeast invertase in the cytosol - vac-inv tobacco plant with yeast invertase in the vacuole - WT wild-type tobacco plant The authors thank A. Großpietsch for her able technical assistance. This work has been supported by the Bundesminister für Forschung und Technologie.     

Metabolism of free sugars in relation to starch synthesis in the developing Sorghum vulgare grain

Accumulation of starch at expense of its free-sugar precursors was studied in the developing grains of the ‘SL-44’variety of Sorghum vulgare Pers. The content of starch gradually increased with the maturation of the grain and this increase was relatively fast until 18 days after anthesis. The daily rate of starch accumulation was at a maximum 15 days after anthesis. The content of total free sugars, reducing sugars, non-reducing sugars other than sucrose, total and non-sucrosyl fructose, and glucose also increased, reaching maximum values at 18 days after anthesis. Sucrose content gradually increased with a concomitant decrease in the activity of invertase, and sucrose was the major non-reducing sugar in the matured grains. Detached heads incubated in labelled sugars indicated that, compared to sucrose and fructose. ¹⁴C was more efficiently incorporated from glucose into grain starch, which was maximally synthesized at the mid-milky stage of grain development. Exogenous supply of NAD⁺ plus ATP stimulated the in vivo incorporation of ¹⁴C from sucrose to starch. The decline in the rate of starch accumulation did not synchronise with that of protein synthesis.     

‘台农1号’芒果果实发育过程中的糖分积累与相关酶活性研究

以‘台农1号’芒果为材料,测定了果实生长发育过程中淀粉、蔗糖、葡萄糖和果糖含量以及淀粉酶、蔗糖代谢相关酶———酸性转化酶(AI)、中性转化酶(NI)、蔗糖合成酶(SS)和蔗糖磷酸合成酶(SPS)的活性,并对果实中糖组分与酶活性的关系进行了分析.结果显示,(1)台农1号芒果果实属于单S型生长曲线,发育前期主要积累淀粉、葡萄糖和果糖,果实成熟软化时,淀粉酶活性降至最低,淀粉水解,蔗糖快速积累.(2)酸性转化酶活性在果实整个发育过程中维持最高,完熟时略有降低;蔗糖磷酸合成酶在果实发育前期略有降低,完熟时升至最高;蔗糖合成酶和中性转化酶活性在整个发育期一直很低且较稳定.(3)淀粉含量与淀粉酶活性呈显著正相关,与SPS活性呈极显著负相关,蔗糖、葡萄糖含量均与SPS、SS呈显著、极显著的正相关;果糖含量与SS呈极显著的正相关.研究表明,芒果成熟时淀粉分解、酸性转化酶活性的降低,且蔗糖合成酶和蔗糖磷酸合成酶活性的增加是引起果实蔗糖积累的主要因子.