Variability for Free Sugars and Organic Acids in Capsicum chinense

Variability in the concentrations of the chemical constituents that contribute to fruit flavor in Capsicum chinense is poorly documented in the scientific literature. We surveyed fruit of 216 landraces and cultivated varieties of Capsicum chinense acquired from North, Central, and South America, and analyzed these for concentrations of the simple sugars sucrose, glucose, and fructose, and citric, malic, succinic, fumaric, and ascorbic acids. Concentrations (mg/100 g Fresh Weight (FW) of whole fruit) of sucrose, glucose, and fructose in fruit of this species ranged from 0.0 to 150, 68 to 701, and 101 to 823, respectively. The total of these sugars (sucrose+glucose+fructose) ranged from 198 to 1543 mg/100 g FW. Concentrations of organic acids ranged from 0.0 (not detected) to 818, 430, 340, and 232 mg/100 g FW for citric, malic, fumaric, and succinic acids, respectively. However, the relative ranking in the concentrations of the individual acids was genotype‐dependent. Total ascorbic‐acid values ranged from 30 to 1466 mg/100 g FW. These data serve to document the range in the concentrations of individual sugars and acids present in mature C. chinense fruit and suggest that this variability may lend itself to studies involving the synthesis and/or metabolism of compounds associated with fruit flavor.     

Isolation of Vacuoles from Immature Apple Fruit Flesh and Compartmentation of Sugars, Organic Acids, Phenolic Compounds and Amino Acids

Vacuoles of immature apple fruit (Malus pumila Mill. var. domesticaSchneid.) were obtained by purification using Ficoll densitygradient centrifugation after lysis of the protoplasts by bothmild osmotic shock and the addition of EDTA and BSA. The recoverywas about 35% of the protoplasts. The isolated vacuoles hada mean diameter of about 100 µm. The distribution of sugars, organic acids, phenolic compoundsand amino acids in the vacuole, the cytoplasm and the free spacewas determined. Almost all of the fructose and glucose, themajor sugars of the tissue, were found in the vacuole. Sorbitolwas mainly located in the free space and the vacuole, and sucrosein the free space and the cytoplasm. More than 90% of the malicacid, the main organic acid, was located in the vacuole. Almostall of the phenolic compounds were also deposited in the vacuole. The volumes of the vacuole, the cytoplasm and the free spacein the whole tissue were calculated from the cell numbers ofthe whole tissue, the volume of the isolated protoplasts, andthe volume of the vacuoles present in the protoplast. The soluteconcentration in each compartment was estimated: vacuoles, 888mM; cytoplasm, 37 mM; free space, 57 mM. How these compartmentationsof solutes affected the translocation of sugars into the fruitand the cell expansion is discussed. ¹This paper is contribution A-159 of the Fruit Tree ResearchStation. (Received July 7, 1983; Accepted November 14, 1983)     

Sugars and Organic Acids of Vitis vinifera

Glucose, fructose, galactose, sucrose, maltose, melibiose, raffinose, and stachyose were identified in the leaves, bark, roots, and berries of Vitis vinifera L. var. Thompson Seedless. In addition to these sugars, verbascose and manninotriose were found in the leaves and bark.

Malic, tartaric, citric, isocitric, ascorbic, cis-aconitic, oxalic, glycolic, glyoxylic, succinic, lactic, glutaric, fumaric, pyrrolidone carboxylic, α-ketoglutaric, pyruvic, oxaloacetic, galacturonic, glucuronic, shikimic, quinic, chlorogenic, and caffeic acids were identified in the leaves, bark, roots, and berries.

Glucose, fructose, sucrose, malate, tartrate, and citrate were determined quantitatively in the leaf, petiole, xylem, bark, tendril, bud, puduncle pedicel, berry, lateral roots, and main roots at 4 separate physiological stages of growth. In addition, changes in the concentrations of fructose, glucose, malate, and tartrate in leaves were measured during a 36-day period starting from budburst.

     

Evidence for Compartmentation of Tryptophan in Cultured Plant Tissues: Free Tryptophan Levels and Inhibition of Anthranilate Synthetase

1. Anthranilate synthetase activity in crude extracts from tissue cultures of Daucus carota L. (carrot), Nicotiana tabacum L. (tobacco; cv. Wisconsin 38 and xanthi), Glycine max Merr. (soybean) and Oryza sativa L. (rice) was completely inhibited by l -tryptophan (5 to 50 μM). Mutant carrot and tobacco lines, capable of growth in the presence of 5-methyltryptophan, required 500 to more than 1000 μM tryptophan for complete inhibition of enzyme activity, respectively. 2. Except for the mutant tobacco line, the concentrations of free tryptophan in all tissue cultures tested were greater than the levels necessary to completely inhibit the respective anthranilate synthetase activities in vitro. These findings would indicate that much of the free tryptophan is compartmentalized away from the regulatory enzyme, anthranilate synthetase. This could implicate compartmentalization of the inhibitor as a biosynthetic control mechanism. 3. During the growth of normal and mutant carrot tissues the anthranilate synthetase enzyme must be at least 7.8 and 10.8% active, respectively, in order to accumulate the amount of tryptophan found in the tissues. 4. Of the substrates and cofactors required for anthranilate synthetase activity in vitro, Mg²⁺ and glutamine were present at near optimal levels in the carrot and tobacco tissues, but chorismate was found to be significantly below the optimal concentrations.     

Changes in Free Amino Acids in White and Green Tissues of Variegated Tobacco Leaves during Water Stress

Variegated tobacco leaves, white on one side of the midrib andgreen on the other, were detached from the stem and incubatedunder water stress or turgid conditions for 4 days to determineany changes in the levels of free amino acids. Drastic changes in the free amino acid composition occurredin the green tissue during the water stress period, but onlyvery small changes in the white tissue. During that time, themost striking difference between the two tissues was the largeamount of proline accumulated in the green tissue, but not inthe white. An exogenous supply of sucrose increased the prolinecontent in both tissues during water stress. An exogenous supplyof glutamic acid increased the proline and asparagine contentsin the green tissue, but it increased only the asparagine contentin the white tissue during water stress. (Received May 4, 1982; Accepted August 12, 1982)     

Compartmentation of Organic Acids in Corn Roots. III. Utilization of Exogenously Supplied Acids

The rates of utilization of exogenously supplied ¹⁴C labeled acids by corn roots was compared to the utilization of these acids generated endogenously in the mitochondria from acetate-³H. ¹⁴C-labeled citrate, pyruvate, succinate, glutamate or aspartate were supplied with acetate-³H in a 15 minute pulse and the ¹⁴C and ³H contents of extracted acids were measured over a 4 hour period. It was found, in contrast to previous experiments with malate, that these exogenously added acids were used as rapidly as the endogenous forms. Apparently, therefore, these acids penetrate readily into the mitochondria and do not enter cytoplasmic pools which are not in ready equilibrium with those in the mitochondria. Small amounts of labeled glutamate were produced from succinate-2,3-³H by corn root tissue. Since glutamate would not be expected to be labeled by reactions of the tricarboxylic acid cycle it was concluded that it was produced rather directly from succinate. The minor pool of glutamate generated in this way retained its radioactivity while that generated in the cycle was rapidly lost. An extra-mitochondrial location of this pool of glutamate is therefore suggested.     

Free Radicals Developed in the Amino-Garbonyl Reaction of Sugars with Amino Acids

GA_l5, GA₃, GA₅, GA₁₉, GA₂₀ and GA₂₃ were identified by GC-MS in the acidic ethyl acetate-soluble fraction from the seeds of sweet potato (Ipomoea batatas Lam.). GA₁₉ and GA₂₃ were major GAs in the mature seeds, their contents being about 200 and 160 μg/kg fresh weight, respectively, while those of GA₁₉ and GA₂₃ in immature seeds were below 100 μg/kg fr. wt. The occurrence of glycosyl conjugates of GA₃, GA₅, GA₈, GA₁₇, GA₁₉, GA₂₀, GA₂₃ and GA₄₄ in the butanol fraction from mature seeds was shown by GC/MS analysis after enzymatic hydrolysis.

Besides the endogenous GAs in sweet potato, those in immature seeds of several other Convolvulaceae plants were investigated. The species of endogenous GAs were discussed in terms of chemotaxonomy.     

Variability of Bacterial Community Composition on Leaves Between and Within Plant Species

The phyllosphere is one of the largest habitats for terrestrial microorganisms. To gain a better insight into the factors underlying the composition of bacterial communities inhabiting leaf surfaces we performed culture-dependent and independent (Denaturing Gradient Gel Electrophoresis) analyses on the bacteria associated with the leaves of three plant species: Amygdalus communis, Citrus paradisi, and Nicotiana glauca. We found that the culturable classes Bacilli and Actinobacteria were the predominant classes on the phyllosphere of all three plant species. In contrast to this consistency on the bacterial class level, we found a significant variation on the bacterial species-level based on the culturable methods. Although some variation was detected among individual plants within one plant species, the inter-specific variability exceeded the intra-specific variability. C. paradisi leaf surface had the highest predicted total species richness (Chao 2 and ICE) and the highest species diversity (βw) among the three plant species. Our findings demonstrate that environmental conditions, mainly the plant species within a site, govern the bacterial community composition on leaf surfaces.     

Changes in Nucleic Acids and Sugars of Tobacco Leaves during Maturity Stage and Flue-curing

Changes in the contents of nucleic acids and sugars in tobacco leaves during maturity stage and flue-curing were investigated. The content of RNA continued to decrease during both periods and is lower in lower leaves on the stalk. However, a temporary reverse trend was observed after topping. A sharp decrease after topping in ribonuclease activity was followed by an increase in RNA several days later, and thereafter soluble protein also increased temporarily in maturity stage.

Sucrose, glucose and fructose decreased temporarily after topping and then increased gradually in the latter stage of maturity, followed by an abrupt increase in the yellowing stage of flue-curing. Minor sugars, i.e. maltose, ribose, mannose, galactose and xylose were determined quantitatively in tobacco leaves. However, these sugars have not shown any remarkable changes during maturity stage and flue-curing.     

Compartmentation in Vicia faba Leaves: I. Kinetics of C in the Tissues following Pulse Labeling

Leaflets of Vicia faba were pulse-labeled with ¹⁴CO₂ to follow the subsequent movement of photosynthate between leaf tissues. Samples were taken during a ¹²CO₂ chase, quick frozen, freeze-substituted, and embedded in methacrylate. Paradermal sections provided tissue samples consisting only of upper epidermis, palisade parenchyma, spongy parenchyma and veins, spongy parenchyma, or lower epidermis. Most CO₂ fixation occurred in the palisade parenchyma, but its ¹⁴C content declined rapidly after labeling. Concomitant with the decline of activity in the palisade parenchyma, there was an increase in activity in the spongy parenchyma and upper epidermis and a slow increase in the lower epidermis. Activity in the palisade parenchyma and spongy parenchyma eventually reached similar levels and remained constant. Tissue samples containing veins were consistently the most radioactive, and activity in those samples showed a decline. Very little change occurred in the insoluble fraction from any tissue. The results support previous assumptions regarding the pathway of assimilate transport to the veins, and demonstrate the rapidity of such transport. Sucrose is apparently the principal mobile compound.     

Changes in Concentrations of Sugars and Organic Acids in the Long-Lasting Flower Clusters of Phalaenopsis

The explanation for the maintenance of the quality of flowerclusters in Phalaenopsis for up to four weeks or more was determined.The concentration of sugars and organic acids and the dailycourse of CO₂ exchange in the florets, the flower stalk andthe leaves of intact and cut flower clusters were determined.The concentration of sugars in florets of the cut flower clustersdecreased progressively and linearly to 25% of the initial value.The concentration of organic acids in the flower stalk of theintact flower cluster increased progressivly, whereas the concentrationof malic acid in the flower stalk of the cut cluster decreased.The levels of sugars and organic acids in leaves in the absenceof a flower cluster was higher than those in leaves in the pressenceof a cluster. The leaves and the flower cluster were relatedas source and sink organ, respectively. The level of sugarsin the flower cluster remained high level for a long periodof time. The results indicate that the stalk'is capable of photosynthesisand has the characteristics of weak-CAM plants. The photosynthateproduced by the stalk served to maintain the quality of thecut flower cluster for at least for 50 days and that of theintact flower cluster. (Received August 22, 1991; Accepted September 30, 1991)     

不同品种药用菊花中游离糖类及游离氨基酸含量的HPLC分析

为比较不同品种菊花的品质特征,本文采用HPLC法测定其游离糖类及游离氨基酸的含量.结果表明,不同品种菊花中游离糖类主要成分是果糖和葡萄糖,蔗糖和麦芽糖未检出,总游离糖类含量约为9.07～18.76g/1O0g,其中黄山贡菊中含量最高,为18.76g/100g,黄菊中最低,为9.07g/100g;其总游离氨基酸含量约为0.563～2.806g/100g,七月菊中含量最高,为2.806g/100g,杭白菊中最低,为0.563g/100g.     

Cation Exchange Capacity, Chemical Composition and the Balance of Carboxylic Acids in the Floral Parts of Various Plant Species

Floral and other parts of antirrhinum, fuchsia, daffodil, andmaize have been analysed for cation-exchange capacity (CEC),major and trace-element constituents, and carboxylic acids.The two dicot species, but not the monocot species, have a gradientof CEC, Ca, and Ca/K increasing along the style and into theovary. Trace-element levels in anthers and ovaries are oftenhigher than in the adjacent filaments and styles. The floralparts of daffodil, with the exception of ovary, ovary wall,and anthers, have closely related K/Ca and citric/malic acidratios which are comparable with those for the rest of the plant.     

Separation of o-Phthaldialdehyde Derivatives of Free Amino Acids from Plant Tissues by Isocratic Reverse-phase High-performance Liquid Chromatography

A reverse-phase high-performance liquid chromatography procedurehas been developed for rapid separation and quantitation offree amino acids as o-phthaldialdehyde derivatives. A two stepisocratic solvent system was used which enabled an accurateanalysis at nanomole level. However, two major disadvantagesto this procedure were the lack of reaction of proline and theco-elutions of threonine/glycine and tryptophan/methionine.The free amino acids in Zea mays roots were separated by usingthe method described. Amino acids, liquid chromatography, o-phthaldialdehyde derivatives, reverse-phase chromatography, Zea mays L, maize, corn     

实验动物血及组织游离氨基酸含量

本文报告实验动物血及组织游离氨基酸含量,结果表明,实验狗和Wistar大鼠血游离氨基酸含量比较恒定。实验兔组织游离氨基酸含量普遍高于血。     

Compartmentation of Organic Acids in Corn Roots II. The Cytoplasmic Pool of Malic Acid

The major conclusion drawn was that malate generated in corn roots during a 15-minute period of CO₂ fixation and malate introduced into the tissue during a similar period from the bathing medium share a common extramitochondrial compartment, the cytoplasmic pool. The utilization of these 2 forms of malate is normally much slower than that of malate generated in the mitochondria by the tricarboxylic acid cycle. By lowering the pH of the medium or treating the tissue with malonate or 2,4-dinitrophenol, similar increases in the rates of utilization of both forms of cytoplasmic malate were brought about. Changes in (A) the demand for acetyl acceptors in the mitochondria and (B) mitochondrial permeability were invoked to account for the increased utilization of the cytoplasmic malate under the various experimental treatments.     

Chicoric and Chlorogenic Acids in Plant Species from Georgia

Chicoric acid was isolated from dandelion (Taraxacum officinaleWigg.) leaves by column chromatography. Conditions for HPLC analysis of chicoric and chlorogenic acids were optimized. These acids were assayed in some plants growing in Georgia. The optimum conservation temperature for the preservation of chicoric and chlorogenic acids in the leaves of dandelion and bilberry (Vaccinium arctostaphylosL.) was determined.