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Dive into the research topics where Helena Šircelj is active.

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Featured researches published by Helena Šircelj.


Journal of Agricultural and Food Chemistry | 2010

Lipophilic Antioxidants and Some Carpometric Characteristics of Fruits of Ten Processing Tomato Varieties, Grown in Different Climatic Conditions

N. Kacjan Maršić; Helena Šircelj; D. Kastelec

Microclimatic conditions and fruit maturity can affect the health-promoting compounds in tomato fruits. The aim of this study was to evaluate the influence of Mediterranean and continental weather conditions, on fruit firmness and coloration as well as on the concentrations of lycopene, alpha- and beta-carotene and lutein and on alpha-, delta- and gamma-tocopherol, in fruits of 10 processing tomato varieties. Compositional data analysis was carried out in order to determine the composition of carotenoids and tocopherols. Mediterranean weather conditions associated with agricultural practice have contributed to faster fruit ripening, which significantly improved the coloration with all varieties, and significantly increased the concentration of total carotenoids and lycopene with varieties with oval and elongated fruits. Environmental conditions in a low tunnel increased the red coloration, but did not significantly increase the content of either total carotenoids or tocopherols. The cultivar and the location of cultivation had a strong effect on the composition of the analyzed lipophilic antioxidants.


Journal of Crop Improvement | 2005

The Effects of Natural CO2 Enrichment on the Growth of Maize

Dominik Vodnik; Helena Šircelj; Damijana Kastelec; Irena Maček; H. Pfanz; Franc Batič

SUMMARY Maize plants (Zea mays) were grown in a field influenced by a geothermal source of CO2 (CO2 spring Stavešinci, Slovenia). Yield parameters and the content of photosynthetic pigments, mineral nutrients, antioxidants and soluble sugars were measured and the photo-synthetic performance was followed in plants growing at different CO2 conditions. Growth parameters were negatively correlated with the soil CO2 concentration as measured at 20 cm depth. Analysis of A-Ci curves revealed lower maximum photosynthesis (CO2-saturated photosynthesis) and lower carboxylation efficiency in high CO2 plants when compared to low CO2 plants. Several biochemical parameters, as the decrease in chlorophyll content and the increase in antioxidants indicate stress in plants exposed to a high CO2 environment.


Water Air and Soil Pollution | 1999

Bioindication of Different Stresses in Forest Decline Studies in Slovenia

Franc Batič; P. Kalan; H. Kraigher; Helena Šircelj; P. Simončič; N. Vidergar-Gorjup; B. Turk

Determination of the stresses operating on a forest ecosystem demands the use of several bioindication methods. Air quality indicators were assessed from an inventory of forest decline based on the assessment of tree crowns and epiphytic lichens. Photosynthetic pigments, ascorbic acid and major macronutrients were studied in Norway spruce needles as indicators of physiological and biochemical stress. Analyses were carried out on selected forest plots in polluted areas (Zasavje district, vicinity of thermal power plants) and predominantly unpolluted areas (Triglav National Park, Julian Alps, Slovenia). For some bioindication methods, there was good agreement with measured air quality and climatological parameters. The best agreement was found between total foliar sulphur in needles and epiphytic lichens, especially in more polluted areas. Agreement with forest decline inventories and analyses of some needle stress physiological/biochemical parameters was less convincing. The strength of agreement was further decreased by soil characteristics and climatic parameters, influenced also by biotic parameters and forest stand history and management. It was concluded that there is no simple bioindication method available to evaluate the vitality of a forest.


Israel Journal of Plant Sciences | 2010

Determination of seco-iridoid and 4-pyrone compounds in hydro-alcoholic extracts of Gentiana lutea L. subsp. symphyandra Murb. leaves and roots by using high performance liquid chromatography.

Anita Kušar; Helena Šircelj; Dea Baričevič

In view of the increasing interest in herbal remedies and their important role in health maintenance and well-being, a study was carried out to clarify the role and importance of the solvent in the extraction process. Hydro-alcoholic (methanol or ethanol) or water extraction procedures for secondary metabolites from Gentiana lutea subsp. symphyandra leaves and roots were optimized for the yield of compounds that have proved to act antioxidatively. Using high performance liquid chromatography (HPLC), the contents of seco-iridoid glucosides (gentiopicroside, amarogentin) and 4-pyrones (mangiferin (xanthone), homoorientin (flavone C-glycoside), isovitexin (flavone C-glycoside)) in Gentiana lutea subsp. symphyandra extracts were determined. The analysis revealed that the contents of observed secondary metabolites in Gentiana lutea subsp. symphyandra extracts varied significantly based on the solvent (methanol, ethanol, and water) used in the extraction procedure. Seco-iridoids and 4-pyrone contents in extract...


Journal of Food Science | 2016

Wild Prunus Fruit Species as a Rich Source of Bioactive Compounds.

Maja Mikulic-Petkovsek; Franci Stampar; Robert Veberic; Helena Šircelj

Sugars, organic acids, carotenoids, tocopherols, chlorophylls, and phenolic compounds were quantified in fruit of 4 wild growing Prunus species (wild cherry, bird cherry, blackthorn, and mahaleb cherry) using HPLC-DAD-MSn. In wild Prunus, the major sugars were glucose and fructose, whereas malic and citric acids dominated among organic acids. The most abundant classes of phenolic compounds in the analyzed fruit species were anthocyanins, flavonols, derivatives of cinnamic acids, and flavanols. Two major groups of anthocyanins measured in Prunus fruits were cyanidin-3-rutinoside and cyanidin-3-glucoside. Flavonols were represented by 19 derivatives of quercetin, 10 derivatives of kaempferol, and 2 derivatives of isorhamnetin. The highest total flavonol content was measured in mahaleb cherry and bird cherry, followed by blackthorn and wild cherry fruit. Total phenolic content varied from 2373 (wild cherry) to 11053 mg GAE per kg (bird cherry) and ferric reducing antioxidant power antioxidant activity from 7.26 to 31.54 mM trolox equivalents per kg fruits.


Journal of Environmental Science and Health Part A-toxic\/hazardous Substances & Environmental Engineering | 2009

Remediation of Cu-contaminated soil using chelant and EAOP

Maja Pociecha; Helena Šircelj; Domen Lestan

An electrochemical advanced oxidation process (EAOP) was used for treatment of the washing solution obtained during leaching of Cu (364 ± 2 mg kg−1) contaminated soil, with chelant S,S isomer of ethylenediamine disuccinate ([S,S]-EDDS). In the EAOP (constant current density 40 mA cm−2), a boron-doped diamond anode was used for the generation of hydroxyl radicals and oxidative decomposition of [S,S]-EDDS-metal complexes in the washing solution. The released Cu was mostly electro-deposited on the stainless-steel cathode. Three consecutive additions of 5 mmol kg−1 [S,S]-EDDS removed 46% of the Cu from the soil, mostly from carbonate and oxide soil fractions (87 and 99% Cu reduction). The soil Cu oral availability in the simulated stomach and intestinal phases (in vitro physiologically based extraction test) was reduced by 5.5 and 4.6-times. Cu plant availability (in vitro diethylenetriamine pentaacetate test) was reduced by 3.6-times. The discharge solution was clear, almost colorless, with pH 8.4, 0.45 mg L−1 Cu and 0.01 mM EDDS.


Food Chemistry | 2018

Is foliar enrichment of pea plants with iodine and selenium appropriate for production of functional food

Ana Jerše; Nina Kacjan Maršić; Ana Kroflič; Mateja Germ; Helena Šircelj; Vekoslava Stibilj

Pea (Pisum sativum L.) plants were sown in a field and foliar sprayed at blooming stage with solutions of different forms of iodine (I) - I- and IO3- and selenium (Se) - SeO32- and SeO42-. The possibility of enrichment of pea seeds to nutritionally important levels of both elements and their distribution through the plant parts were studied. To evaluate stress caused by application of I and Se, some morphological, physiological and biochemical characteristics were determined. The results showed elevated concentrations of both elements in all parts of pea plants. In seeds, I content was more than 6-fold higher, while Se content was up to 12-fold higher than in control plants. Although the plants were in good condition, some differences in pod characteristics and electron transport system activity were observed. Glutathione content was not affected by any treatment and only the I- + SeO42- combination decreased the amount of anthocyanins in plants.


Chemistry & Biodiversity | 2017

Sorbus aucuparia and Sorbus aria as a Source of Antioxidant Phenolics, Tocopherols, and Pigments.

Katarina Šavikin; Gordana Zdunić; Dijana Krstić-Milošević; Helena Šircelj; Danijela Stešević; Dejan Pljevljakušić

Due to its nutritive and medicinal properties, berries of some Sorbus species are used for the preparation of jams and jelly as well as in traditional medicine. On the other hand, their chemical composition is not much studied especially of those grown in Balkan Peninsula. We have analyzed individual phenolics, tocopherols, carotenoids and chlorophylls using HPLC in berries from Sorbus aucuparia and Sorbus aria collected in different localities in Serbia and Montenegro together with the amounts of total phenolics and proanthocyanidins as well as their radical scavenging activity against DPPH radical. Berries of S. aucuparia were richer source of polyphenolics in comparision with S. aria and, regardless the species and locality, caffeoylquinic acids such as neochlorogenic and chlorogenic acid were the most abundant compounds. Among analyzed tocopherols the most abundant in all samples was α‐tocopherol (0.48 – 19.85 μg/g dw) as it was β‐carotene among carotenoids (mean concentration of 0.98 μg/g dw in S. aucuparia and 0.40 μg/g dw in S. aria, respectively). Correlation between total phenolics and DPPH radical scavenging activity was noticed. Our study represents comprehensive report on chemical composition of S. aucuparia and S. aria which could contribute to a better understanding of their quality.


Journal of Experimental Botany | 2004

The glutathione system as a stress marker in plant ecophysiology: is a stress-response concept valid?

Michael Tausz; Helena Šircelj; Dieter Grill


Journal of Plant Physiology | 2005

Biochemical responses in leaves of two apple tree cultivars subjected to progressing drought

Helena Šircelj; Michael Tausz; Dieter Grill; Franc Batič

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Franc Batič

University of Ljubljana

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Mateja Germ

University of Ljubljana

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