Parsnip Roots Research Articles

Changes in sugar and starch concentrations in parsnip (Pastinaca sativa L.) during root growth and development and in cold storage

SummaryLow-temperature sweetening of parsnip (Pastinaca sativa L.) roots, which may occur both pre-harvest and post-harvest, is a well-known phenomenon, but is poorly understood. ‘White King’ parsnip roots were analysed over two seasons (2008 and 2009) during field growth and over six months cold storage at 1ºC for their dry matter content, as well as their starch, sucrose, glucose, fructose, and malto-oligosaccharide (MOS) concentrations and for their changes in amylolytic enzyme activities (2009 only). In 2008, when the air temperature fell below 5ºC for 12 d in the last 8 weeks before harvest, the concentration of starch decreased significantly (P ≤ 0.05) and the concentration of total sugar increased significantly. In 2009, when temperatures did not fall below 5°C during the last 8 weeks before harvest, the concentrations of starch (339 + 17 mg g–1 DW) and total sugars (168 + 12 mg g–1 DW) did not change significantly. However, in both years, during 24 weeks in cold storage at 1ºC, starch levels were almost completely depleted, whereas sucrose concentrations and, to a lesser extent, MOS concentrations increased at least two-fold. Glucose and fructose concentrations also increased significantly during 24 weeks in cold storage, but to a much lower level than sucrose or MOS. Total amylolytic activity and α-amylase activity doubled during the first 8 weeks in cold storage, whereas β-amylase activity did not change significantly. As products of α-amylase activity, changes in MOS concentration paralleled the changes in α-amylase activity. The accumulation of sucrose and MOS may raise the culinary quality of cold-stored parsnip.

Effects of cultivation conditions and cold storage on the polyacetylene contents of carrot (Daucus carota L.) and parsnip (Pastinaca sativa L.)

SummaryPolyacetylenes are a class of highly bioactive compounds which may negatively affect the sensory properties of Apiaceous plants such as carrots and parsnips. In the present study, the effects of organic nitrogen fertilisation, water supply, and cold storage on the contents of falcarinol (FaOH), falcarindiol (FaDOH), and falcarindiol-3-acetate (FaDOAc) were investigated in four carrot (Daucus carota L.) and two parsnip (Pastinaca sativa L.) cultivars. Relatively high contents of polyacetylenes were observed at an early developmental stage of the roots of both carrot and parsnip, decreasing to a transient minimum approx. 1 month prior to harvest maturity.The supply of super-optimal levels of nitrogen (50 or 100 kg N ha–1) using organic fertiliser did not significantly affect the polyacetylene contents of carrot or parsnip at harvest (except FaDOH contents in ‘Rodelika’ carrot). Different levels of water supply to potgrown carrots in climate chambers induced complex, cultivar-dependent, and apparently development-dependent patterns of change in polyacetylene contents and profiles. Cold storage of field-grown ‘Bolero F1’ and ‘Rodelika’ carrot significantly increased the levels of individual polyacetylenes in both cultivars. However, carrots previously supplied with super-optimal amounts of nitrogen fertiliser (50 or 100 kg N ha–1) either showed a transient increase (‘Bolero F1’) or a transient decline (‘Rodelika’) in polyacetylene contents during cold storage. The results suggest active pre- and post-harvest synthesis and metabolism of polyacetylenes in carrot and parsnip. This may affect the sensory and bio-functional properties of these crops.

Effect of different pre-sowing tillage on quantity and quality of parsnip (Pastinaca sativa L.) root yield in ridge cultivation

Parsnip is a very valuable vegetable due to its nutritional value and dietetic quality. It is moreover herbal raw material abundant in active substances. The yield quality of vegetables greatly depends on thorough pre-sowing soil tillage. The present study aimed at evaluating the influence of different presowing soil tillage (medium-deep ploughing, cultivating) and plant growing methods, flat or ridge cultivation, on the yield of parsnip and some biometric traits of its roots. The field experiment was carried out in 1999, 2000 and 2002 on lessive soil with the granulometric composition corresponding to medium silty loam. The parsnip cultivar 'Półdługi Biały' was the experimental plant species. The cultivation of parsnip on ridges had a significant influence on increased total yield of roots and decreased yield of small roots, as compared to flat cultivation. A significant increase in unit weight of the root and its diameter in the top part was also recorded in the latter type of cultivation. Spring pre-sowing tillage had no significant effect on parsnip yields. An increasing trend was observed only for total and marketable root yield in the ploughed plots. When parsnip is grown on lessive soil (which has an unstable structure), plants cultivated on ridges after spring pre-sowing plough are the most beneficial treatment combination.

Effects of storage conditions on furocoumarin levels in intact, chopped, or homogenized parsnips.

Furocoumarins represent a family of natural food constituents with phototoxic and photomutagenic properties. They are found mainly in plants belonging to the Rutaceae and Umbilliferae such as celery, carrots, and parsnips. Parsnips (Pastinaca sativa L.) have become more and more popular as a vegetable, e.g., as a constituent of or ingredient in baby food. Previous work has shown that microbial infection of parsnip roots can result in a dramatic increase in furocoumarin levels. In this study, freshly harvested parsnips were stored as whole roots, pieces (cubes), or homogenate at +4 degrees C or -18 degrees C over various time periods under standard conditions. It was found that furocoumarin concentrations (sum of five furocoumarins: angelicin, isopimpinellin, 5-methoxypsoralen, 8-methoxypsoralen, and psoralen) in freshly harvested parsnips, analyzed by HPLC after extraction with diethyl ether and sequential solid phase (reversed-phase and silica) extraction, was generally lower than 2.5 mg/kg, and storage of parsnips in any form investigated at -18 degrees C over up to 50 days did not lead to a marked increase in furocoumarin levels. In contrast, storage of whole parsnips, but not of cubes or homogenate, at +4 degrees C resulted in a marked biphasic increase of furocoumarin concentrations after 7 and 38 days of storage up to levels of about 40 mg/kg. A dramatic increase in furocoumarin concentrations up to 566 mg/kg was observed when whole parsnips obtained from the market were kept at room temperature over 53 days, resulting in a visible microbial (mold) infection. Baby food products from the German market containing parsnips as an ingredient or constituent showed furocoumarin levels < or =0.41 mg/kg, suggesting that properly stored roots/preparations have been used. It is recommended that, after harvesting, parsnips be kept at -18 degrees C or under other conditions that prevent microbial infections.

Patterns of defensive chemical production in wild parsnip seedlings (Apiaceae: Pastinaca sativa L.)

To ascertain patterns of allocation between growth and defense in seedlings, we measured plant biomass and the amount of six furanocoumarin defensive chemicals in wild parsnip roots and shoots (Apiaceae: Pastinaca sativa L.) in sequential harvests for sixty days following emergence and compared them to previous studies on mature plants. Furanocoumarins were present from the first day of emergence and were actively synthesized from the onset of seedling growth. Although initial amounts of each furanocoumarin species differed, they were produced at the same rate. Furanocoumarin production was not commensurate with biomass accretion, and fluctuations in concentration varied dramatically between roots and shoots. Concentrations of furanocoumarins in seedlings are far lower than in adult plants, perhaps because the selective regime of seedlings differs from that of mature plants, and inter-seedling competition favors investment in growth rather than defense.

The legacy of Atropos, the fate who cut the thread of life.

The legacy of Atropos, the fate who cut the thread of life.

Effect of addition of dried healthy or diseased parsnip root tissue to a modified AIN-76A diet on cell proliferation and histopathology in the liver, oesophagus and forestomach of male Swiss Webster mice

Umbelliferous crop plants, including the parsnip ( Pastinaca sativa L.), elaborate enhanced levels of furocoumarins, including psoralens, when subjected to biotic or abiotic stress. These furocoumarins are recognized to lead to phototoxicity. In this study, the effect of these agents, which are present in diseased parsnip root tissue, on the liver and two tissues on the route of entry to the body (the oesophagus and forestomach) were investigated. Young male Swiss Webster mice were fed for approximately 30 days with modified AIN-76A diets containing 32.5% dried healthy, 32.5% apparently healthy or 32.5% fungicide-treated parsnip root tissue, and 8, 16 or 32.5% dried diseased ( Phoma complanata-infected) parsnip root tissue. As controls, three modified AIN-76A diets differing in their edible starch-to-sucrose ratios (C1–C3) were administered for an equal time. Dried healthy parsnip root tissue, compared with controls, did not significantly affect any of the indices of cellular proliferation or histopathological parameters that were assessed. Histopathological examination of the oesophagus and forestomach demonstrated no significant changes as a result of feeding any of the diets containing parsnip tissue. In the liver, the highest level (but neither of the two lower levels) of dried diseased parsnip root tissue led to swelling of the cytoplasm in cells surrounding the central vein of hepatic lobules, with consequent compression of the peripheral cells. Using [ 3H]thymidine radioautography, a dose-related increase in cell labelling with the level of diseased parsnip root tissue was demonstrated in the liver. Compared with control diet C2 only, the extent of [ 3H]thymidine labelling in the liver was increased in mice receiving apparently healthy parsnip tissue; a slight, not statistically significant, increase was also noted with fungicide-treated parsnip tissue. Increased [ 3H]thymidine labelling with the feeding of diseased parsnip tissue was also found in the greater curvature of the forestomach and the region of the oesophageal-forestomach junction, but not at the glandular junction of the forestomach nor in the mid-oesophagus.

Effect of Gene Disruption of Trichodiene Synthase on the Virulence ofGibberella pulicaris

Gibberella pulicaris (anamorph: Fusarium sambucinum) accumulates the trichothecene, 4,15-diacetoxyscirpenol (DAS), a potent, host-nonspecific phytotoxin and eukaryotic protein synthesis inhibitor. To investigate the role of DAS in plant pathogenesis, we tested the virulence of five hygromycin-resistant (Hygr) transformants that carry a disrupted gene for trichodiene synthase (Tox5) and no longer produce DAS in vitro or in planta. Virulence levels of all five DAS- transformants were reduced on parsnip root slices, but high levels of virulence were retained on potato tuber slices. Tetrad analysis of one transformant, strain BC51, which carried a single copy of the transforming plasmid, resulted in either cosegregation of the Hygr DAS-, parsnip reduced-virulence phenotypes or in the simultaneous loss of all three traits. In contrast, all progeny from these tetrads, whether DAS+ or DAS-, were highly virulent on potato tubers. Moreover, the Hygr DAS- phenotype was recovered at high frequency from mixed populations after one 3-wk cycle in potato tubers, which suggested that loss of DAS production did not reduce competitiveness of the pathogen. We conclude that DAS accumulation increases the virulence of G. pulicaris on parsnip root but does not affect virulence on potato tubers. The apparent effect of the host on the importance of DAS in virulence is still unexplained, but it suggests that when assessing the role of trichothecenes in plant disease, one should be cautious in generalizing results from one plant species to another.

83. Sugar Content of Parsnip Root Tissues During Low Temperature Storage

83. Sugar Content of Parsnip Root Tissues During Low Temperature Storage

Sweetening of Parsnip Roots During Short-Term Cold Storage

Parsnip (Pastinaca sativa cv. All-American) were assessed for free sugars at harvest and after storage for 3, 7 and 14 days at 0° and 10°C. Sugar accumulation was more rapid in roots stored at 0° than 10°C and in the core than in the cortex. Roots stored for 7 days at 0°C were perceived to be sweeter than roots stored for the same period at 10°C or freshly-harvested roots, suggesting that an improvement in the eating quality of roots during short-term cold storage is possible, but temperature dependent. The four principal sugars in roots after 2 weeks of storage at 0°C included sucrose, fructose, glucose and an unidentified trisaccharide.

Microscopic Detection and Identification of Various Substitute Vegetable Tissues in Ground Horseradish

Turnip root, parsnip root, potato tuber, and corn kernels have been used as adulterants in the preparation of horseradish sauce and horseradish powder. The diagnostic histological features of horseradish root and its known adulterants are described and illustrated as viewed through a polarizing microscope with cross polars and a first order red plate. A procedure which can be used to detect any of the known adulterants in horseradish is described. The adaptation of a previously reported semiquantitative method is also discussed.

Furanocoumarin Phytoalexins, Trichothecene Toxins, and Infection ofPastinaca sativabyFusarium sporotrichioides

Many plant pathogenic fusaria produce trichothecenes, which are potent phytotoxins and inhibitors of protein synthesis in eukaryotes. In this study we show that a wild-type, trichothecene-producing strain of F. sporotrichioides, NRRL 3299, is pathogenic on Pastinaca sativa (parsnip) roots and produces T-2 toxin in planta. Parsnip roots infected with this strain also accumulate high levels of fungitoxic furanocoumarins, mainly xanthotoxin and angelicin. Analysis of serial sections of infected roots showed that furanocoumarin concentrations decease sharply at the infection boundary to levels apparently insufficient to completely block fungal growth or trichothecene production. The involvement of trichothecenes in pathogenesis was investigated by using three presiously isolated, complementary mutants of NRRL 3299, blocked at different steps in T-2 toxin biosynthesis. T-2 toxin production is restored when these mutants are grown together pairwise and each mutant accumulates different end products. In this study the ability of these mutants to infect parsnips correlates with their ability to produce certain trichothecenes. Thus, the mutant that accumulates 4,15-diacetoxyscirpenol, a trichothecene nearly as toxic as T-2 toxin, is as pathogenic as the wild-type parent. In contrast, neither the mutant that accumulates the less toxic calonectrin analogues nor the mutant that accumulates the nontoxic trichothecene precursor, trichodiene, is pathogenic. Furthermore, coinocul ation of these latter two mutants on parsnip roots results in infection.

Abstracts of papers presented at the annual meeting of the Canadian Phytopathological Society University of British Columbia, Vancouver 14-17 August 1988

Abstracts of papers presented at the annual meeting of the Canadian Phytopathological Society University of British Columbia, Vancouver 14-17 August 1988

Activity of compound G2 isolated from alfalfa roots against medically important yeasts

Screening of various vegetables as biocatalysts for the stereoselective bioreduction and resolution of racemic bicyclo[3.3.1]nonane-2,6-dione was performed. Vegetables of the family Apiaceae, i.e. the roots of parsnip (Pastinaca sativa), celery (Apium graveolens), parsley (Petroselinum crispum) and carrot (Daucus carota) were found to be the best. The methodology described here allows the efficient enantioseparation of (+)-enantiomer of bicyclo[3.3.1]nonane-2,6-dione. The reaction time, temperature and the amount of celery roots were optimized and (+)-enantiomer was obtained with the optical purity of 90–98% and the yield of more than 90%.

Naturally-occurring crystals of photocarcinogenic furocoumarins on the surface of parsnip roots sold as food

Normal levels of total furocoumarins in fresh parsnip roots are as high as 96 ppm (wet weight). In older ‘spoiled’ and diseased parsnips freely available in grocery stores these values may be increased by 2500%. So high are the amounts in some instances, that mixed crystals of furocoumarins can be detected on the surfaces of the parsnip roots by both conventional low powered microscopy and SEM. The principal crystal form was angelicin but the presence of psoralen, 5-MOP and 8-MOP was confirmed by HPLC, TLC, photobiological assay and analysis of mass spectra.

Natural toxicants in human foods: psoralens in raw and cooked parsnip root.

Parsnip root contains three photoactive, mutagenic, and photocarcinogenic psoralens in a total concentration of about 40 parts per million. These chemicals are not destroyed by normal cooking procedures (boiling or microwave); thus humans are exposed to appreciable levels of psoralens through the consumption of parsnip and possibly other psoralen-containing foodstuffs. The toxicologic consequences to man of such exposure may be speculated on the basis of medicinal and laboratory studies, but epidemiologic data are not available.

Selective vital staining of companion cells of potato tuber and parsnip root with neutral red.

When staining the internal phloem region of a potato tuber with the vital stain neutral red, it was observed that files of elongated cells of narrow diameter were heavily stained and were easily distinguishable from the more isodiametric parenchyma cells, many of which did not stain with neutral red. The elongated cells were identified as companion cells by locating the adjacent sieve-tube members through counterstaining with aniline blue and reviewing under violet light. Of a number of other plants surveyed, only parsnip roots possessed companion cells exhibiting a similar slective staining. In other plants both the companion cells and the surrounding parenchyma cells usually stained. Sieve-tube members never accumulated neutral red. It was concluded that the vacuoles of the companion cells of the potato tuber were stained by the ion trap mechanism because of the color of the accumulated stain, the lack of staining when neutral red was applied in an acidic solution, and the complete destaining after soaking in dilute ammonium hydroxide.

Determination of Structure and Composition of Suberin from the Roots of Carrot, Parsnip, Rutabaga, Turnip, Red Beet, and Sweet Potato by Combined Gas-Liquid Chromatography and Mass Spectrometry

Suberin from the roots of carrots (Daucus carota), parsnip (Pastinaca sativa), rutabaga (Brassica napobrassica), turnip (Brassica rapa), red beet (Beta vulgaris), and sweet potato (Ipomoea batatas) was isolated by a combination of chemical and enzymatic techniques. Finely powdered suberin was depolymerized with 14% BF(3) in methanol, and soluble monomers (20-50% of suberin) were fractionated into phenolic (<10%) and aliphatic (13-35%) fractions. The aliphatic fractions consisted mainly of omega-hydroxyacids (29-43%), dicarboxylic acids (16-27%), fatty acids (4-18%), and fatty alcohols (3-6%). Each fraction was subjected to combined gas-liquid chromatography and mass spectrometry. Among the fatty acids very long chain acids (>C(20)) were the dominant components in all six plants. In the alcohol fraction C(18), C(20), C(22), and C(24) saturated primary alcohols were the major components. C(16) and C(18) dicarboxylic acids were the major dicarboxylic acids of the suberin of all six plants and in all cases octadec-9-ene-1, 18-dioic acid was the major component except in rutabaga where hexadecane-1, 16-dioic acid was the major dicarboxylic acid. The composition of the omega-hydroxyacid fraction was quite similar to that of the dicarboxylic acids; 18-hydroxy-octadec-9-enoic acid was the major component in all plants except rutabaga, where equal quantities of 16-hydroxyhexadecanoic acid and 18-hydroxyoctadec-9-enoic acid (42% each) were found. Compounds which would be derived from 18-hydroxyoctadec-9-enoic acid and octadec-9-ene-1, 18-dioic acid by epoxidation, and epoxidation followed by hydration of the epoxide, were also detected in most of the suberin samples. The monomer composition of the six plants showed general similarities but quite clear taxonomic differences.

Chemical attractants for larvae of Costelytra zealandica (Coleoptera: Scarabaeidae)

In controlled laboratory tests, using shallow glass chambers containing a coarse river sand substrate between ‘blank’ and ‘test’ sample cages, 3rd‐instar larvae of Costelytra zealandica (White) were attracted to parsnip and carrot root, freshly ground nutmeg, and s‐pinene (a constituent common to these materials). The terpenol a‐fenchol was strongly attractive to the larvae. Ryegrass root, α‐pinene, and limonene were not significantly attractive, and limonene may indeed have some repellent effect.

The control of the production of lactate and ethanol by higher plants

Factors controlling the production of ethanol and lactate have been examined using cell free extracts prepared from pea seeds (Pisum sativum var Alaska) and parsnip roots (Pastinaca sativa). The result suggest that under aerobic conditions pyruvate decarboxylase is inactive. With the onset of anaerobiosis glycolysis leads to an accumulation of lactate with a corresponding fall in pH. The fall in pH activates pyruvate decarboxylase and initiates competition between lactate dehydrogenase and pyruvate decarboxylase for pyruvate. The effect of pyruvate concentration on the partitioning has been analysed in terms of a modified Wegscheider rule and shows that the ratio lactate dehydrogenase activity/pyruvate decarboxylase activity bears an inverse relationship to the pyruvate concentration. The decrease in ratio which occurs when the pyruvate concentration rises is enhanced by the co-operativity which is exhibited by pyruvate decarboxylase. The pH optimum of lactate dehydrogenase is alkaline whilst the pH optimum of pyruvic decarboxylase is acid, thus the two enzymes function as a pH-stat. The possibility of excessive production of lactic acid is further controlled by the response of lactate dehydrogenase to ATP; the enzyme is inhibited by ATP and the inhibition increases as the pH decreases. It is suggested that this mechanism functions to protect the plant from excess production of acid.