Yazar "Demirbas, Sefer" seçeneğine göre listele

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    A comparative study of the antimicrobial properties and antioxidant enzyme activities of field-grown and in vitro-propagated plants of endemic Digitalis trojana Ivanina
    (Inst Bioloska Istrazivanja Sinisa Stankovic, 2017) Corduk, Nursen; Demirbas, Sefer; Dogru, Nurcihan Hacioglu
    The antimicrobial properties and antioxidant enzyme activities of field-grown and in vitro-propagated plants of Digitalis trojana Ivanina (Helen of Troy foxglove), a perennial endemic plant species of Turkey, were compared. The field work was carried out in May and July 2014, and plant samples of D. trojana were collected from Kazdagi (Turkey). Propagation of D. trojana was achieved by culturing leaf explants on MS medium supplemented with 13.3 mu M 6-benzyl-aminopurine (BA) and 0.53 mu M alpha-naphthaleneacetic acid (NAA). The antimicrobial activity, plant lipid peroxidation levels and antioxidant enzyme (superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), ascorbate peroxidase (APX), glutathione reductase (GR)) activities were analyzed in 12- and 17-week-old in vitro-grown Digitalis plants collected in May and July from two different localities at 430 and 1173 m above sea level. Although the in vitro-propagated plants had very low antagonistic activities compared to field-grown plants, they exhibited remarkably similar antibacterial activities against Escherichia coli ATCC 11230, Pseudomonas aeruginosa ATCC 27853 and Bacillus subtilis ATCC 6633. There were no important differences between plants collected from the two localities (430 and 1173 m a. s. l.). Biochemical analysis showed that the antioxidant enzyme (SOD, APX, GR) activities of field-grown plants were higher than in vitro-grown plants. Also, the difference in altitude at which the plants were grown was apparently linked to decreases in antioxidant enzyme activities, except for POX in field-grown plants collected in July.
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    ALTERATIONS IN ANTIOXIDATIVE ENZYME ACTIVITIES CAUSED BY BORON TOXICITY IN TWO TOMATO CULTURE VARIETIES
    (Parlar Scientific Publications (P S P), 2012) Oluk, Esin Akcam; Acar, Okan; Demirbas, Sefer; Duran, Havva; Atik, Ebru; Gorkem, Hulya Nur
    Boron (B) is an essential micronutrient for normal growth of higher plants. On the other hand, its toxicity is also a significant problem that can limit plant growth on soils of arid and semi-arid environments in agricultural regions across the world. In this study, two tomato (Lycopersicon esculentum Mill.) varieties (SC2121 and SAFARI F1) are used, and toxic effects of B treatment (3 mM) were studied. Germination was not affected, and seeds of both varieties germinated nearly to 100%. These in vitro germination experiments were accomplished in MS medium. Malondialdehyde (MDA) content, and antioxidant enzyme activites (superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR)) were investigated in root and shoot tissues of tomato seedlings. Oxidative damage increased with 3-mM B treatment in tissues of SC2121 plants compared to control, and antioxidant enzyme activities were decreased, except APX. B toxicity inhibited only CAT activity in root tissues, but CAT, GR, SOD, PDX and APX activities were inhibited in shoot tissues of SAFARI F]. However, B toxicity in this variety did not cause oxidative damage. Root tissue of SAFARI F1 variety, in particular, was found to be a better protection than SC2121. This might indicate that SAFARI F1 variety is based on the protection of antioxidant enzymes. However, similar protections against B toxicity were not detected in shoot tissues of both varieties.
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    PHYSIOLOGICAL AND BIOCHEMICAL DEFENSE REACTIONS OF ARABIDOPSIS THALIANA TO PHELIPANCHE RAMOSA INFECTION AND SALT STRESS
    (Parlar Scientific Publications (P S P), 2017) Demirbas, Sefer; Acar, Okan
    The effects of salinity stress on growth parameters and the activities of antioxidant enzymes (superoxide dismutase (SOD), peroxidase (PDX), catalase (CAT), glutathione reductase (GR), and ascorbate peroxidase (APX)) were investigated in Arabidopsis thaliana during Phelipanche ramosa mediated biotic stress. The experiment was conducted using 100 mM NaCl on infected 18-day old A. thaliana plants in Gamborg B5 medium. P. ramosa infection reduced root length and shoot dry weight (DW) in A. thaliana. After salt stress treatment shoot fresh weight (FW) decreased in A. thaliana plants infected with P. ramosa. Salt stress treatment produced a significant reduction in carotenoid and total chlorophyll content while it did not change the chl a/b ratio of infected plants. PDX and APX activities increased during P. ramosa infection in A. thaliana. Additional NaCl treatment decreased the level of lipid peroxidation accompanied by an increment in SOD, PDX, GR, CAT and APX activities, while chl a/b ratio and total chl content decreased. These results, presented for the first time, demonstrated induction of the antioxidant defense system against P. ramosa infection by NaCl treatment in A. thaliana.
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    Superoxide dismutase and peroxidase activities from antioxidative enzymes in Helianthus annuus L. roots during Orobanche cumana Wallr. penetration
    (Parlar Scientific Publications (P S P), 2008) Demirbas, Sefer; Acar, Okan
    Orobanche spp. (broomrapes) are holoparasitic angio-C, sperms that subsist on the roots of dicotyledonous plants. Broomrapes are the most destructive weeds since they extract water and photosynthate directly from crop plants, causing crop yield and quality to reduce significantly. The occurrence of total superoxide dismutase and total peroxidase activities during broomrape-sunflower interaction were studied on three different cultivars (cv. Pioneer 4223, cv. Sanay and cv. Isera) of Helianthus annuus. Total superoxide dismutase activities increased on day 7 post-inoculation in cv. Pioneer 4223 and cv. Isera compared with control plants, whereas a decrease during all days in cv. Sanay was observed. In the variety of Orobanche-resistant cv. Pioneer 4223, the increases in the total superoxide dismutase activities were supported by the total peroxidase activities in the first 5 days, which indicate that the detoxification of the reactive oxygen species produced during the Orobanche penetration seems to be related to the Orobanche resistance in the sunflower. An increase has been determined in the total SOD activities from the first to the seventh day, but this increase was not found parallel to that in the total POX activities in cv. Isera.. This situation may indicate sensitivity for cv. Isera. Total peroxidase activities increased for the first 7 days in cv. Sanay compared with control plants. Total superoxide dismutase and total peroxidase activities were not a statistically significant change during all days in treatment plants compared with control plants in cv. Sanay. This change in SOD activities may indicate sensitivity of both cv. Isera and cv. Sanay to broomrape unless they are treated with herbicide.
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    The effects of glyphosate isopropylamine on mitotic activity, superoxide dismutase and peroxidase activities of Allium cepa L. root tip cells
    (2010) Acar, Okan; Demirbas, Sefer; Dhan, Dogan; Ozdinc, Nagme
    Glyphosate is a broad-spectrum herbicide that can widely be used in agricultural and non-agricultural fields. Glyphosate isopropylamine affects the inhibition of the biosynthesis of aromatic amino acids, and also that of some enzymes involved in the shikimic acid pathway. The aim of this research was to study the effects of different concentrations of glyphosate isopropylamine (0.5, 1, 2 and 5%) on the mitotic activity in Allium cepa L. root tip cells and the superoxide dismutase (SOD) and peroxidase (POX) activities in Allium cepa L. roots. Glyphosate isopropylamine concentrations of 0.5, 1 and 2% did not lead to a significant change in the mitotic activity compared to the control group. However, for the concentration of 5%, a steep decline was observed in 48-h treatment of the substance, in comparison to that of 24 h. Total SOD activity decreased in the 24-h treatment group of glyphosate isopropylamine compared to the control group, whereas with the concentrations of 2 and 5% no SOD activity was observed. However, the POX activity increased only with 1% concentration, with regard to the control group, whereas it did not change with the other concentrations. © by PSP.
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    THE EFFECTS OF GLYPHOSATE ISOPROPYLAMINE ON MITOTIC ACTIVITY, SUPEROXIDE DISMUTASE AND PEROXIDASE ACTIVITIES OF Allium CEPA L. ROOT TIP CELLS
    (Parlar Scientific Publications (P S P), 2010) Acar, Okan; Demirbas, Sefer; Ilhan, Dogan; Ozdinc, Nagme
    Glyphosate is a broad-spectrum herbicide that can widely be used in agricultural and non-agricultural fields. Glyphosate isopropylamine affects the inhibition of the biosynthesis of aromatic amino acids, and also that of some enzymes involved in the shikimic acid pathway. The aim of this research was to study the effects of different concentrations of glyphosate isopropylamine (0.5, 1, 2 and 5%) on the mitotic activity in Allium cepa L. root tip cells and the superoxide dismutase (SOD) and peroxidase (POX) activities in Allium cepa L. roots. Glyphosate isopropylamine concentrations of 0.5, 1 and 2% did not lead to a significant change in the mitotic activity compared to the control group. However, for the concentration of 5%, a steep decline was observed in 48-h treatment of the substance, in comparison to that of 24 h. Total SOD activity decreased in the 24-h treatment group of glyphosate isopropylamine compared to the control group, whereas with the concentrations of 2 and 5% no SOD activity was observed. However, the POX activity increased only with 1% concentration, with regard to the control group, whereas it did not change with the other concentrations.