Factors affecting aluminum tolerance of cells in carrot (Daucus carota L.) suspension cells

Aluminum toxicity and related nutrient deficiencies, such as phosphorus deficiency, are considered to be major environmental constraints on food production world wide (Foy 1983). Toxic effects of Al in cells are characterized by the inhibition of cell division (Morimura et al. 1978) and nuclear activity (Matsumoto et al. 1977). Therefore, a plant cell culture system could be used as a model system for the physiological study of aluminum toxicity in higher plants. For such a study, it is important to initially define the factors affecting cell responses to aluminum toxicity.     

Effect of physiological activities on aluminum uptake in carrot (Daucus carota L.) cells in suspension culture

Responses to aluminum (AI) of carrot (Daucus carota L.) cells in suspension culture (hereafter referred as “carrot suspension cells”) were investigated under different physiological activities. The respiration rate of the cells at the logarithmic growth phase decreased when the external Al concentration increased. A similar tendency was observed for the ATP content of the cells when the external Al concentration of the medium increased. Decrease of about 50% of the respiration rate and of about 35% of the ATP content of the cells was. observed at 300 µm AlCl₃ at 24 h, respectively. The Al content (total and citrate-insoluble AI) in cells increased when the external Al concentration increased. Both the respiration rate and the ATP content in cells were reduced when the culture temperature decreased or ATP synthesis inhibitors, namely CCCP (carbonylcyanide-m-chlorophenylhydrazone) and DNP (2,4-dinitrophenol) were added. The addition of SHAM (salicylhydroxamic acid) did not affect the ATP content in cells. The Al content of the cells treated with 50 µm Al together with SHAM was similar to that of the cells treated with only AI. However, the Al content of the cells increased when the cells were treated with 50 µm Al together with CCCP, DNP, or a low temperature (15°C). The content of citrate Al content in cells increased rapidly when ATP synthesis inhibitors were present or the culture temperature was low. There was a negative linear correlation between the Al content and the ATP content in cells. These results suggest that the cells containing a large amount of ATP and showing normal functions of the plasma membranes may display an apparent tolerance to Al by suppressing Al absorption into their cytoplasm at a cell suspension level.     

Isolation and identification of novel pyranoanthocyanins from black carrot (Daucus carota L.) juice

Six novel pyranoanthocyanins were identified by HPLC-ESI-MSn in black carrot (Daucus carota L. ssp. sativus var. atrorubens Alef.) juice. The two major compounds, namely, the vinylcatechol adducts of cyanidin 3-O-(6-O-feruloyl-beta-D-glucopyranosyl)-(1-->6)-[beta-D-xylopyranosyl-(1-->2)]-beta-D-galactopyranoside and cyanidin 3-O-[beta-D-xylopyranosyl-(1-->2)]-beta-D-galactopyranoside, respectively, were isolated by a combination of high-speed countercurrent chromatography with semipreparative HPLC. Their structures were fully elucidated by means of one- and two-dimensional NMR spectroscopy and high-resolution mass spectrometry. The four remaining pigments were characterized as the vinylphenol and vinylguaiacol adducts of cyanidin 3-O-[beta-D-xylopyranosyl-(1-->2)]-beta-D-galactopyranoside, the vinylguaiacol adduct of cyanidin 3-O-(6-O-feruloyl-beta-D-glucopyranosyl)-(1-->6)-[beta-D-xylopyranosyl-(1-->2)]-beta-D-galactopyranoside, and the vinylcatechol adduct of cyanidin 3-O-(6-O-sinapoyl-beta-d-glucopyranosyl)-(1-->6)-[beta-D-xylopyranosyl-(1-->2)]-beta-D-galactopyranoside. These compounds are formed during storage of the juice through the direct reaction of either caffeic, ferulic, or coumaric acid with the respective genuine anthocyanins.     

Impact of egyptian broomrape (Orobanche aegyptiaca (Pers.) parasitism on amino acid composition of carrot (Daucus carota L.)

The relationship between the organic nitrogen status of Egyptian broomrape and one of its hosts, carrot, was studied by comparing amino acid profiles of leaf and root tissues of nonparasitized and broomrape-parasitized carrot plants and by analyzing amino acid profiles of broomrape at different growth stages. Total N concentrations, expressed as a percentage of the dry weight of the tissues, were similar in leaves of nonparasitized and parasitized carrot plants but were lower in parasitized roots than in nonparasitized roots. In both dry and germinated broomrape seeds, N concentrations were lower than or similar to those in broomrape tubercles, shoots, or callus. Individual amino acid concentrations in hydrolysates of leaves of parasitized carrot plants tended to be similar to or greater than those in hydrolysates of nonparasitized carrot plants. Roots of parasitized plants tended to have similar or lower amino acid concentrations than roots of nonparasitized plants. Dry and germinated broomrape seeds had similar amino acid profiles, but individual amino acid concentrations were lower than in the other broomrape tissues examined. The broomrape shoot tended to have lower amino acid concentrations than the tubercle and callus. Free amino acid profiles of leaves and roots of parasitized plants paralleled those of nonparasitized plants, respectively. Individual free amino acids tended to occur at similar or lower levels in dry and germinated broomrape seeds than in the tubercle, shoot, or callus. Free amino acid composition of the broomrape tubercle was similar to that of the parasitized root. Arginine and alanine concentrations in broomrape callus were dramatically higher than those of other amino acids in this or other tissues investigated. These results indicate that changes in the composition of both free and bound amino acids in carrot are associated with broomrape parasitism.     

Inheritance of purple colour and its different flavonoids profiling in F2 populations of tropical carrot (Daucus carota L.)

Genetic Resources and Crop Evolution - The results of the inheritance study revealed that the purple root epiderm (Pe) and cortex (Pcx) colour were dominant over the yellow colour of epiderm (ye)...     

Structural and sensory characterization of compounds contributing to the bitter off-taste of carrots (Daucus carota L.) and carrot puree

Sequential application of solvent extraction, gel permeation chromatography, and HPLC in combination with taste dilution analyses revealed that not a sole compound but a multiplicity of bitter tastants contribute to the bitter off-taste of cold-stored carrots and commercial carrot puree, respectively. Among these bitter compounds, 3-methyl-6-methoxy-8-hydroxy-3,4-dihydroisocoumarin (6-methoxymellein), 5-hydroxy-7-methoxy-2-methylchromone (eugenin), 2,4,5-trimethoxybenzaldehyde (gazarin), (Z)-heptadeca-1,9-diene-4,6-diin-3,8-diol (falcarindiol), (Z)-heptadeca-1,9-diene-4,6-diin-3-ol (falcarinol), and (Z)-3-acetoxy-heptadeca-1,9-diene-4,6-diin-8-ol (falcarindiol 3-acetate) could be identified on the basis of MS as well as 1D- and 2D-NMR experiments. Due to the low concentrations of <0.1 mg/kg and the high taste thresholds found for eugenin and gazarin, these compounds could be unequivocally excluded as important contributors to the bitter taste of carrots. Calculation of bitter activity values as the ratio of their concentration to their bitter detection threshold clearly demonstrated that neither in fresh and stored carrots nor in commercial carrot puree did 6-methoxymellein contribute to the bitter off-taste. In contrast, the concentrations of falcarindiol in stored carrots and, even more pronounced, in carrot puree were found to be 9- and 13-fold above its low bitter detection concentration of 0.04 mmol/kg, thus demonstrating that this acetylenic diol significantly contributes to the bitter taste of the carrot products investigated.     

Anthocyanin composition of black carrot (Daucus carota ssp. sativus var. atrorubens Alef.) cultivars Antonina, Beta Sweet, Deep Purple, and Purple Haze

This study aimed to identify the pigment composition of black carrot (Daucus carota ssp. sativus var. atrorubens Alef.) cultivars Antonina, Beta Sweet, Deep Purple, and Purple Haze. Cyanidin 3-xylosyl(glucosyl)galactosides acylated with sinapic acid, ferulic acid, and coumaric acid were detected as major anthocyanins by high-performance liquid chromatography with diode array detection (HPLC-DAD) and with electrospray ionization multiple mass spectrometry (HPLC-ESI-MS(n)) analyses. The preparative isolation of these pigments was carried out by means of high-speed countercurrent chromatography (HSCCC). The color activity concept was applied to the isolated anthocyanins at three pH values. Cyanidin 3-xylosyl(sinapoylglucosyl)galactoside was found to exhibit a lower visual detection threshold and a higher pH stability than cyanidin 3-xylosyl(feruloylglucosyl)galactoside and cyanidin 3-xylosyl(coumaroylglucosyl)galactoside. The color parameters of the fresh roots of the four cultivars were described by the CIELab coordinates L* (lightness), C* (chroma), and h(ab) (hue angles). Total phenolics varied among the cultivars and ranged from 17.9 to 97.9 mg gallic acid equivalents (GAE)/100 g fresh weight (fw). For the content of monomeric anthocyanins, values between 1.5 and 17.7 mg/100 g fw were determined.     

Quantitative analysis of aroma compounds in carrot (Daucus carota L.) cultivars by capillary gas chromatography using large-volume injection technique

Dynamic headspace sampling was used to collect aroma compounds from raw samples of four carrot (Daucus carota L.) cultivars (Brasilia, Duke, Fancy, and Cortez). The collected volatiles were analyzed by capillary GC-FID and GC-MS using large-volume cool on-column injection (LVI-COC). Of the 36 compounds identified, 6 had not been previously detected in carrots. Significant differences between the carrot cultivars were found for 31 of the identified volatiles as well as for total monoterpenes, sesquiterpenes, and total volatile content. Mono- and sesquiterpenes accounted for about 98% of the total volatile mass in all cultivars. LVI-COC injection was used to determine the loss of carrot volatiles during concentration of headspace samples under a stream of nitrogen. The loss among major monoterpenes in the concentrated samples varied from 16% for p-cymene to >40% for alpha-pinene as compared to nonconcentrated samples. The loss among high-boiling sesquiterpenes varied from not detectable (beta-caryophyllene, alpha-humulene, and caryophyllene oxide) to approximately 7% for (E)- and (Z)-gamma-bisabolene.     

Genetic analysis of root traits in tropical carrots (Daucus carota L.)

Genetic Resources and Crop Evolution - Carrot root being used as vegetable and salad due to the nutritional value, hence consumers demanding carrot production. Thus, the production can be achieved...     

Possible relationships between wild and cultivated carrots (Daucus carota L.) in the Netherlands

Summary A theory about the descent and development of modern carrot cultivars in Europe formulated byBanga (1963) is discussed. According to this author, the cultivated carrot originates from Afghan carrot material. Furthermore, the origin of carrots with fleshy, orange roots is suggested to lay in the Netherlands in the 17th century.However, it is shown that wild populations of the carrot with white coloured roots have occurred in Europe since prehistoric times. During the late Middle Ages and Renaissance these carrots were used as medicinal plants. It is suggested that these indigenous carrots have played a minor role in the development of modern cultivated carrots.

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Verwandtschaftliche Beziehungen zwischen wilden und kultivierten Möhren (Dau-cus carota L.) in den Niederlanden (Daucus carota L.)

Zusammenfassung Die vonBanga (1963) formulierte Abstammungs- und Entwicklungstheorie über die rezenten Möhrensorten wird diskutiert. Nach seiner Meinung sind die kultivierten Möhren aus afghanischen Formen entstanden. Darüber hinaus wird vermutet, daß Möhren mit fleischigen, orangefarbigen Wurzeln in den Niederlanden im 17. Jahrhundert entwickelt worden sind.Es wird jedoch gezeigt, daß es schon seit prähistorischen Zeiten in Europa Wild-populationen von Möhren mit weißfarbigen Wurzeln gegeben hat. Diese Möhren wurden im späten Mittelalter und in der Renaissance als Heilpflanzen verwendet. In vorliegender Arbeit wird darauf hingewiesen, daß diese heimischen Möhrenformen bei der Entstehung unserer heutigen Möhrensorten eine nur geringe Rolle gespielt haben dürften.

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Chelate-enhanced phytoextraction and phytostabilization of lead-contaminated soils by carrot (Daucus carota)

The objective of this study was to study the influence of different ethylenediamine tetraacetate (EDTA), nitrilotriacetic acid (NTA) and oxalic acid (HOx) concentrations on tolerance and lead (Pb) accumulation capacity of carrot (Daucus carota). The results indicated that by increasing Pb, NTA and HOx concentrations in the soil, the shoot, taproot and capillary root dry matters increase effectively. In contrary, EDTA caused to reduce capillary roots biomass. EDTA was more effective than NTA and HOx in solubilizing soil Pb. The highest Pb content in shoots (342.2 ± 13.9 mg kg^?1) and taproots (301 ± 15.5 mg kg^?1) occurred in 10 mM EDTA, while it occurred for capillary roots (1620 ± 24.6 mg kg^?1) in 5 mM HOx, when the soil Pb concentration was 800 mg kg^?1. The obtained high phytoextraction and phytostabilization potentials were 1208 (±25.6) and 11.75 (±0.32) g Pb ha^?1 yr^?1 in 10 mmol EDTA kg^?1 soil and no chelate treatments, respectively. It may be concluded that chelate application increases Pb uptake by carrots. Consequently, this plant can be introduced as a hyperaccumulator to phytoextract and phytostabilize Pb from contaminated soils.     

Changes in volatile compounds of carrots (Daucus carota L.) during refrigerated and frozen storage

Carrots (Daucus carota L.) of cv. Bolero and cv. Carlo were processed into shreds and stored for up to 4 months at -24 degrees C (frozen storage), or the roots were stored for up to 4 months at 1 degrees C (refrigerated storage) followed by processing into shreds. Volatiles from the carrot shreds were collected by dynamic headspace technique and analyzed by GC-FID, GC-MS, GC-MS/MS, and GC-O to determine the volatile composition and aroma active components of carrots stored under different temperature conditions. A total of 52 compounds were quantified, of which mono- and sesquiterpenes accounted for approximately 99% of the total volatile mass. Major volatile compounds were (-)-alpha-pinene, beta-myrcene, (-)-limonene, (+)-limonene, (+)-sabinene, gamma-terpinene, p-cymene, terpinolene, beta-caryophyllene, alpha-humulene, and (E)- and (Z)-gamma-bisabolene. A considerable increase in the concentration of mono- and sesquiterpenes was observed during refrigerated storage, whereas the concentration of terpenoids was around the same level during frozen storage. GC-O revealed that the major volatiles together with (+)-alpha-pinene, (-)-beta-pinene, (+)-beta-pinene, 6-methyl-5-hepten-2-one, (-)-beta-bisabolene, beta-ionone, and myristicin had an odor sensation, which included notes of "carrot top", "terpene-like", "green", "earthy", "fruity", "citrus-like", "spicy", "woody", and "sweet".     

Mechanical weeding effects on soil structure under field carrots (Daucus carota L.) and beans (Vicia faba L.)

The successful production of organic vegetables relies heavily on mechanical weeding, flame weeding and stale seedbeds. These operations involve repeated passes by tractors. Mechanical weeding also involves regular tillage. This combination of repeated tillage and compaction changes soil structure. We studied these structural changes in two fields of organic carrots and one field of beans in eastern Scotland. Structure was described by measuring soil strength with a vane shear tester and a cone penetrometer, by measuring bulk density and by visual assessment. Under beans, vane shear strength below the growing root zone was highly variable and in some areas was high enough to restrict root growth (>50 kPa). The carrots were grown in beds containing crop rows separated by bare soil. The bare soil was regularly weeded mechanically. The structure of this weeded soil in the top 10 cm layer of a loam eventually became disrupted and compacted enough to deter root growth (vane shear strength of 70 kPa). In addition the topsoil and subsoil in the wheel-tracks between the beds became very compact with little distinguishable structure. This compaction extended to the subsoil and persisted into the next cropping season (cone resistance >3 MPa at 35–50 cm depth). Reduced tillage by discing without ploughing was used to incorporate the straw used to protect the carrots overwinter and prepare the soil for the next crop. The resulting topsoil quality was poor leading to anaerobic growing conditions which restricted growth of the following crop and led to losses of the greenhouse gas nitrous oxide. The greatest threat to soil quality posed by mechanical weeding was subsoil compaction by tractor wheeling.     

Effect of storage temperature on the stability of anthocyanins of a fermented black carrot (Daucus carota var. L.) beverage: shalgam

The effect of temperature on the stability of shalgam anthocyanins stored at 4, 25, and 40 degrees C for 90 days was investigated. The effect of pasteurization and sorbate addition on the anthocyanin stability as compared to control was also studied. The monomeric anthocyanin content and color density decreased with increasing time as a function of storage temperature whereas the percent polymeric color and browning increased. The same trends were observed in control, pasteurized, and sorbate-added shalgam samples. Shalgam anthocyanins consisted of two nonacylated and three acylated cyanidin derivatives. Acylated anthocyanins were more stable when compared to nonacylated ones at all storage temperatures. The activation energies, 11.11-11.64 kcal/mol, were calculated from the reaction rate constants evaluated taking first-order reaction kinetics. The highest anthocyanin retention was observed at 4 degrees C storage temperature with a half-life between 231 and 239 days.     

Aluminum-tolerance of carrot (daucus carota L.) plants regenerated from selected cell cultures

Abstract

Aluminum-tolerant variants from cell cultures of carrot (Daucus carota L. cv. MS Yonsun) were selected by exposing them to excess ionic aluminum. The medium contained A1CI₃ and 0.1 mM phosphate at pH 4.0. Under ionic aluminum stress (0.5-1.0 mM), 282 calli were selected. Twenty-eight fertile plants were regenerated from 7 selected calli. Based on the root elongation tests of the seedlings, the seeds displayed aluminum-tolerance. In the case of the cell line H7-08, the selection occurred at a frequency of ca. 6 × 10^-7 when the materials were plated on agar medium containing 0.5 mM aluminum.     

Effects of harvesting date and storage on the amounts of polyacetylenes in carrots, Daucus carota

The amounts of three main polyacetylenes in carrots; falcarinol, falcarindiol, and falcarindiol-3-acetate, were determined by HPLC, during three seasons, in carrots harvested several times per season and at different locations in Sweden. The amounts of falcarindiol first decreased from a relatively high level and then increased later in the harvest season. The amounts of falcarindiol-3-acetate showed similar variations, whereas the amounts of falcarinol did not exhibit any significant variation during the harvest season. During storage the amount of polyacetylenes leveled off, increasing in samples initially low and decreasing in samples initially high in polyacetylenes. The amounts of all polyacetylenes varied significantly due to external factors and between stored and fresh samples. This variation opens up possibilities to achieve a chemical composition of polyacetylenes at harvest that minimizes the risk of bitter off-taste and maximizes the positive health effects reported in connection with polyacetylenes in carrots.     

Carotenoid profiles and consumer sensory evaluation of specialty carrots (Daucus carota, L.) of various colors

Five different colored carrots were analyzed for their carotenoid profile and underwent sensory evaluation to determine consumer acceptance (n = 96). Four major carotenoids were identified and quantified by use of HPLC methods. High beta-carotene orange carrots were found to contain the greatest concentration of total carotenoids. Except for the white, all the carrots are a significant source of bioavailable carotenoids. Sensory evaluation showed the high beta-carotene orange and white carrots to be favored over the yellow, red, and purple carrots in both blind and nonblind treatments (P < 0.01). However, all the carrots were well accepted by the consumer panel. With this information, carrot growers should be encouraged to cultivate specialty carrots to provide sources of both vitamin A precursors and phytochemicals.     

Reinvestigation of the bitter compounds in carrots (Daucus carota L.) by using a molecular sensory science approach

In order to reinvestigate the key molecules inducing bitter off-taste of carrots ( Daucus carota L.), a sensory-guided fractionation approach was applied to bitter carrot extracts. Besides the previously reported bitter compounds, 6-methoxymellein (1), falcarindiol (2), falcarinol (3), and falcarindiol-3-acetate (4), the following compounds were identified for the first time as bitter compounds in carrots with low bitter recognition thresholds between 8 and 47 micromol/L: vaginatin (5), isovaginatin (6), 2-epilaserine oxide (7), laserine oxide (8), laserine (14), 2-epilaserine (15), 6,8-O-ditigloyl- (9), 6-O-angeloyl-, 8-O-tigloyl- (10), 6-O-tigloyl-, 8-O-angeloyl- (11), and 6-, 8-O-diangeloyl-6 ss,8alpha,11-trihydroxygermacra-1(10) E,4 E-diene (12), as well as 8-O-angeloyl-tovarol (13) and alpha-angeloyloxy-latifolone (16). Among these bitter molecules, compounds 9, 10, 13, and 16 were not previously identified in carrots and compounds 6, 11, and 12 were yet not reported in the literature.     

Improvement of texture properties and flavor of frozen dough by carrot (Daucus carota) antifreeze protein supplementation

The effects of concentrated carrot protein (CCP) containing 15.4% (w/w) carrot (Daucus carota) antifreeze protein on texture properties of frozen dough and volatile compounds of crumb were studied. CCP supplementation lowered the freezable water content of the dough, resulting in some beneficial effects including holding loaf volume steadily and making the dough softer and steadier during frozen storage. Furthermore, SPME-GC-MS analysis showed CCP supplementation did not give any negative influences on volatile compounds of crumb and gave a pleasant aroma felt like Michelia alba DC from trans-caryophyllene simultaneously. Combining our previous results that CCP supplementation improves the fermentation capacity of the frozen dough, CCP could be used as a beneficial additive for frozen dough processing.     

Alternative methods of carrot (Daucus carota) protection against the northern root knot nematode (Meloidogyne hapla)

Abstract

The presence of northern root knot nematode (Meloidogyne hapla) has considerably increased in the Czech Republic during the last 10 years. The management of this pest is difficult; thus, the aim of this study was to test two alternative pest management techniques on carrots under field conditions. When Indian mustard (Brassica juncea) was ploughed and the treated area was then covered with polyethylene sheets to prolong effect of the treatment, the root gall numbers decreased; whereas a nitrolime application combined with plastic covering had a positive effect on the experimental plants’ fresh weight.