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Öğe 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 NurBoron (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.Öğe Alterations in antioxidative enzyme activities caused by boron toxicity in two tomato culture varieties(2012) Oluk, Esin Akçam; Acar, Okan; Demirbaç, Sefer; Duran, Havva; Atik, Ebru; Görkem, Hülya NurBoron (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 Fl) 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, POX and APX activities were inhibited in shoot tissues of SAFARI Fl. However, B toxicity in this variety did not cause oxidative damage. Root tissue of SAFARI Fl variety, in particular, was found to be a better protection than SC2121. This might indicate that SAFARI Fl variety is based on the protection of antioxidant enzymes. However, similar protections against B toxicity were not detected in shoot tissues of both varieties. by psp.Öğe Biomonitoring and annual variability of heavy metal concentration changes using moss (Hypnum cupressiforme L. ex. Hedw.) in Canakkale province(2006) Acar, OkanMoss transplants of the species Hypnum cupressiforme L. ex Hedw. were used as active biomonitoring organisms. The moss samples were exposed at a Canakkale province site for 12 months for subsequent analysis of metal concentration (Cr, Cd, Pb, Fe, Ni, Mn). This field experiment was carried out to investigate the accumulation of the metals over a period of 3, 6, 9 and 12 months at 10 sample places. Results of heavy metal deposition indicated that metal concentration in the moss samples generally increased with the length of exposure and was higher at the roadside site. Heavy metal deposition was found in Canakkale province heavily polluted by Fe, Ni, Mn, Pb and Cr between the dates 12.06. 2002-17.03.2003. Consequently, oil and coal pollution is observed in Canakkale province. This pollution caused a very heavy metal deposition on moss especially on the lower grounds of the province in comparison to the higher ground. Apart from Cd, all different types of metal deposition are observed annually. © 2006 Asian Network for Scientific Information.Öğe Comparative Analysis of Alfalfa Mutants in Response to Drought Stress Applied After First Cutting(Springer, 2024) Cetin, Selcuk; Tiryaki, Iskender; Sari, Ugur; Acar, OkanThe purpose of this study was to determine the agro-morphological, physiological, and transcriptional characteristics of ethyl methane sulfonate (EMS)-mutagenized M3 alfalfa (Medicago sativa L.) mutants grown for 24 days under water deficit conditions following the first cutting at the blooming bud stage. Drought stress generally reduced all agro-morphological parameters measured. Cutting stress significantly reduced total chlorophyll contents of all genotypes, with the exception of mutant X20. Significant changes occurred in the levels of ascorbate peroxidase (APX), lipid peroxidation (TBARS), glutathione reductase (GR), superoxide dismutase (SOD) and crude protein levels. Drought stress considerably elevated GR levels in irrigated control (C1) and unirrigated control (C2) plants. In contrast to the other genotypes studied, mutant X20's crude protein level increased significantly after the first cutting under 24 days of water deficit conditions, compared to the level found before cutting. The expression profiles of Medicago truncatula Response to Desiccation 2 (MtRD2) and Medicago sativa proline dehydrogenase (MsProDH) genes differed based on the plant genotype and duration of drought stress. Drought stress increased MsProDH gene expression in X20, X50, and C2 plants by 4.57, 14.8, and 20.65 times, respectively. The findings of the expression study indicated that the MtRD2 gene may play a key role in stress reduction rather than drought stress per se. The results of this study revealed that cutting and drought are two independent stress variables that should be evaluated separately when evaluating genotype response to both irrigated and unirrigated growing environments in alfalfa.Öğe Comparison of Drought Tolerance of Some Wheat Varieties Grown in Turkey(2022) Günay, Eda; Acar, OkanThe effect of drought stress on 21 wheat (Triticum aestivum L.) varieties were screened at the germination stage for drought tolerance. Four levels of osmotic stress was assessed by applying different polyethylene glycol (PEG-6000; 0%, 10%, 15% and 20% (w/v)) concentrations. Germination rate, root-shoot length, total chlorophyll amount (SPAD), specific leaf area (SLA), relative water content (RWC), superoxide anion (O2.?) and hydrogen peroxide (H2O2) accumulation were determined on the 8th day after sowing. The increased osmotic stress, significantly reduced germination rate, root-shoot length, SLA, chlorophyll amount and RWC in KateA-1, Gelibolu and Sultan-95 varieties. Pehlivan, Karahan-99 and Tekirdağ varieties were less affected by osmotic stress and these varieties were determined as drought tolerant varieties than other varieties.Öğe Comparison of Two Bacillus Strains Isolated from the Coastal Zone in Barley (Hordeum vulgare L.) Under Salt Stress(MDPI, 2025) Yildiz, Muge Teker; Acar, OkanSalt stress is one of the most important abiotic stress factors that negatively affects sustainable crop production, agricultural productivity, and microbial life. Increasing salt stress negatively affects the growth and development of barley, posing a threat to global food security. It is now known that inoculation of plant growth-promoting rhizobacteria (PGPR) has significant potential in increasing stress tolerance and yield in agricultural products. This study focused on the effects of Bacillus cereus CUN6 and Bacillus thuringiensis SIRB2, isolated from the coastal zone and tested for their PGPR capacities, on physiological (root length, shoot length, biomass, dry weight) and biochemical (total chlorophyll, total protein, hydrogen peroxide, lipid peroxidation, peroxidase activity (POX), catalase activity (CAT)) analyses in Hordeum vulgare L. seedlings under salt stress. The results showed that the two bacterial inoculations alleviated the negative effects of salt stress by increasing the root-shoot length, biomass, dry weight, chlorophyll content, and total protein content in barley plants. However, B. thuringiensis increased growth and development especially in root length, biomass, and dry weight compared to B. cereus. On the other hand, B. cereus significantly increased root length, biomass, and chlorophyll content under salt stress; these increases were 17%, 5%, and 7%, respectively. B. thuringiensis chlorophyll content increased by 4% in 300 mM NaCl compared to the control. When compared in terms of the antioxidant defense system, B. thuringiensis inoculation was more effective on CAT activity, while B. cereus inoculation was more effective on POX activity. Under salt stress, B. cereus and B. thuringiensis inoculation significantly decreased H2O2 content in barley; these decreases were 16% and 10%, respectively. Additionally, TBARs content was significantly decreased by B. cereus and B. thuringiensis inoculation under salt stress; these decreases were determined as 8% and 9%, respectively, compared to the control. These results indicated that both bacterial inoculations can alleviate the salt tolerance of barley seedlings by regulating antioxidant metabolism. This research focused on the potential of B. cereus and B. thuringiensis as biofertilizers against salt stress in barley based on physiological and biochemical analysis.Öğe Determination of Salt Tolerance of Some Barley Varieties Based on Physiological and Biochemical Properties(2022) Yıldız, Müge Teker; Acar, OkanSalt stress is one of the important environmental factors limiting the growth and productivity of barley (Hordeum vulgare L.) worldwide. Increasing salt stress negatively affects plant growth and development, posing a threat to global food security. In this study, some physiological and biochemical effects of salt stress at different concentrations (0, 50, 100, 200 mM NaCl) on 8 barley varieties (Kıral-97, Harman, Yaprak, Yaba, Larende, Cumhuriyet-50, Kalaycı-97, Çıldır-02) grown in Turkey were determined. For this purpose, the effects of salt stress on root-shoot length, biomass, pigment content, specific leaf area (SLA), relative water content (RWC), lipid peroxidation content (TBARS), hydrogen peroxide (H2O2) (spectrophotometric and histochemical staining) content were determined in 35-day-old seedlings. Our results showed that increased salt stress decreased the root-shoot lengths, biomass, SLA, and pigment contents in Cumhuriyet-50 and Çıldır-02 varieties, while increasing the amount of TBARS and H2O2. It was determined that Yaprak and Yaba varieties were less affected by salt stress and were more resistant to salinity compared to other varieties.Öğe Determination of the Short-Term Drought Stress Tolerance of Three Barley Varieties Using Physiological and Biochemical Changes(2024) Baltacıer, Gamze; Acar, OkanBarley (Hordeum vulgare L.) is an important agricultural plant that can adapt to stress conditions. Abiotic stress factors significantly reduce growth, photosynthetic efficiency and metabolic processes in barley. Drought stress increases reactive oxygen species (ROS) in plant cells, and the antioxidant defense system reduces damage caused by overproduction of ROS. The aim of this study was to determine the physiological and biochemical effects of short-term drought stress on some barley cultivars (Kalaycı-97, Harman and Yaprak) grown in Turkey. In 21-day-old seedlings, short-term drought stress decreased the total chlorophyll content. The amount of total protein reduced in the Harman variety, while it increased by 19% in Kalaycı-97 and 27% in Yaprak. The H2O2 content decreased in Yaprak while increasing by 76% in the Kalaycı-97 variety. It was demonstrated that TBARS levels increased by 62% in Kalaycı-97 and 26% in Yaprak. In other ways, while drought stress caused a 48% decrease in APX activity in Kalaycı-97, it caused a 42% and 20% increase in APX activity in Harman and Yaprak, respectively. However, in Kalaycı-97 and Yaprak, CAT increased by 48% and 69%, respectively. These results indicate that Yaprak genotype is tolerant, Kalaycı-97 sensitive and Harman moderately tolerant to short term drought stress.Öğe Effect of industrial wastewater ontotal protein and the peroxidase activity in plants(Academic Journals, 2009) Akı, Cüneyt; Guneysu, Esra; Acar, OkanThe aim of this study is to investigate the effects of industrial wastewaters on protein and the peroxidase activity in Lycopersicon esculentum Mill., Capsicum annuum L., Phaseolus vulgaris L. and Vicia faba L. Industrial wastewaters were taken from Dardanel Fisheries Company, Tekel alcoholic drinks companies' wastewater treatment plants and from one station which is located in the middle of the Sari ay River. Wastewaters were applied to 6 weeks old plants with directly irrigation water. Physiological changes in the plants were observed by the means of measuring the protein and enzyme activity. The largest increase in protein was observed as 190.9 and 136.3% in V. faba treated with Sari ay River water and Tekel wastewater, respectively. In P. vulgaris which was treated with Dardanel wastewater, the total protein amount increased by 84% compared to control plants. After the wastewater treatment, the peroxidase activity decreased in all plants. The largest peroxidase decrease was 80% in L. esculentum treated with Tekel wastewater. In P. vulgaris, peroxidase decreased by 59 and 51% when treated with Dardanel wastewater and Sari ay River water, respectively. It was concluded that the increase in total protein amount and the decrease in peroxidase activity demonstrated the industrial wastewater's blocking effects on plants defense systems.Öğe Effects of drought stress factors on antibacterial activity of two Triticum aestivum L. varieties(University of Nis Faculty of Science and Mathematics, 2019) Acar, Okan; Hacıoğlu Doğru, NurcihanTriticum aestivum L. (Wheat grass), one of the members of Poaceae family, has been considered to be a very efficient therapeutic drug. In the present study, we propose to evaluate antibacterial effects of the two varieties of T. aestivum L. [cv. Tosunbey (drought tolerant) and cv. Sultan 95 (drought-sen-sitive)] which grown in three different stress conditions [(1) drought stress; (2) pre-treatment of seeds with acetyl salicylic acid; (3) drought stress and pre-treatment of seeds with acetyl salicylic acid]. The antibacterial activity of the ethanol extracts was assayed against five pathogens (Pseudomonas aeru-ginosa ATCC 27853, Proteus vulgaris ATCC 13315, Escherichia coli NRRL B-3704, Staphylococcus aureus ATCC 25923 and Bacillus subtilis ATCC 6633) by agar disc diffusion and micro broth dilution methods. The results showed that the ethanol extracts from the different studied treatments showed antibacterial activities, with the diameters of the inhibition zone ranging from 8 to 15 mm and minimum inhibitory concentration ranging from 2.5 to 20.0 µg/mL, respectively. The highest antibacterial activity, against B. subtilis ATCC 6633, was demonstrated by the extract of T. aestivum cv. Sultan 95, which grown in conditions where drought stress and pre-treatment of seeds with acetyl salicylic acid were combined. © 2019 Acar, Hacıoğlu Doğru.Öğe Effects of salt stress factors on antimicrobial activity of two Triticum aestivum L. varieties(University of Nis Faculty of Science and Mathematics, 2019) Hacıoğlu Doğru, Nurcihan; Acar, OkanSalinity is one of the most common environmental stress factors that adversely affect plant growth and crop production in cultivated areas worldwide. Herbal or ‘alternative’ medicine is gaining popularity and scientific research about wheat grass as a “functional food” is becoming more available and popular. Wheat grass, Triticum aestivum L. has a long history and is widely used as a health food supplement. It is found to be used as a treatment for minor ailments, and also as a preventive dietary supplement and therapeutic drug. Current study was aimed at evaluate antimicrobial properties of the two varieties of T. aestivum L. [cv. Tosunbey (drought tolerant) and cv. Sultan 95 (drought sensitive)], grown in three different conditions [(1) control; not treated with salt or acetyl salicylic acid; (2) treatment with sea water; (3) sea water and pre-treatment of seeds with acetyl salicylic acid]. The antimicrobial activity of the ethanol extracts of the two varieties of T. aestivum were assayed against Escherichia coli NRRL B-3704, Pseudomonas aeruginosa ATCC 27853, Proteus vulgaris ATCC 13315, Acinetobacter baumanii ATCC 19606, Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 25923, S. haemolyticus ATCC 43252 and Candida albicans ATCC 10231 test microorganisms by agar disc diffusion method and broth microdilution method. The results showed that the ethanol extracts from the different treatments showed antimicrobial activities, with the diameters of the inhibition zone ranging from 8 to 13 mm and 2.5 to 20 µg/ mL, respectively. The highest antimicrobial activity was demonstrated against P. aeruginosa ATCC 27853 by the extract of T. aestivum cv. Sultan 95, which grown in sea water and whose seeds were pre-treated with acetyl salicylic acid. © 2019 Hacıoğlu Doğru, Acar.Öğe Fungal and bacterial diseases control with Elexa™ plant booster(Parlar Scientific Publications (P S P), 2008) Acar, Okan; Akı, Cüneyt; Erdugan, HueseyinElexa is a plant booster that elicits specific defense responses in various plants against certain fungal and bacterial diseases. Rather than killing hostile fungi that attack plants, Elexa acts as a preventative and stimulative agent to protect plants from pathogens. Elexa contains 4% chitosan. In the present study, a 0.1% concentration of Elexa was used to evaluate the biological efficiency in cucumber (Cucumis sativus L.), tomato (Lycopersicum esculentum Mill.) and potato (Solanum tuberosum L.) plants, as foliar spray against fungal (Botrytis cinerea Pers., gray mold), (Pseudoperanospora cubensis (Berk & Curt) Rostow, downy mildew), (Phytophtora infestans (Mont) de Bary, late blight) and bacterial (Pseudomonas lachrymans (Smith & Ryan) Carsner, angular leaf spot) diseases in greenhouse conditions. Elexa was also used to evaluate the inhibitory effect of in vitro germination against B. cinerea Pets. and P. lachrymans (Smith & Ryan) Carsner. Our results demonstrated that Elexa is a good plant booster for disease management and defense elicitation in commercial formulations. Elexa also exhibited inhibitory effects in in vitro germination of B. cinerea Pers. and P. lachrymans (Smith & Ryan) Carsner. It was observed that chitosan as well as elicitors, such as Elexa, produced with its chitosan content, provide 60% of protection against the damage caused by late blight, gray mold, downy mildew in potato and tomato plants, as well as angular leaf spot in cucumber, respectively.Öğe Genotoxic effects of industrial wastewater on Allium cepa L.(Academic Journals, 2009) Sik, Levent; Acar, Okan; Akı, CüneytThe aim of this research is to study the effects of different concentrations of water on both incoming and outgoing in central biological and chemical wastewater treatment plant in Manisa (Turkey) organized industrial zone (MOIZ) on the Allium cepa L. root meristems, having been rooted in distilled water for 48 h. The union bulbs were kept in the 100% concentrations of the refined water (RW) and of 10, 25, 50 and 100% concentrations of unrefined water (UW). Distilled water was used for the control samples. It was determined that wastewater reduced the rate of the mitotic division of different concentrations and increased the mitotic anomalies. Mitotic index was found to be 33.8, 31.2, 23.6 and 16.7% in the control group, RW, 10% concentration of the UW, and 25% concentration of the UW, respectively. On the other hand, the rates of Mitosis / (Anaphase + Telophase) were 0.23, 0.28, 0.42, 0.71 in the control group, RW, % concentration of the UW, and 25% concentration of the UW, respectively. Plant growth was interrupted in the 50 and 100% concentrations of the UW and the mitotic division was inhibited. No anomalies were encountered in the control group. In the RW, a low rate of anomaly was observed, while in the different concentrations of the UW, chromosomal aberrations such as high frequency of lagging chromosome, irregular distribution, polar slips, horizontal division and sticky chromosome were observed.Öğe Improved drought tolerance of EMS mutagenized Alfalfa (Medicago sativa L.) mutants by in vitro screening at germination stage(Nature Portfolio, 2022) Tiryaki, Iskender; Sari, Ugur; Cetin, Selcuk; Acar, OkanThe objectives of this study were to determine drought tolerant novel mutant of alfalfa (Medicago sativa L.) genotypes by screening EMS mutagenized 340675 M-3 seeds at germination stages in the presence of osmotic stress of 35% PEG(6000). Root growth assay provided several drought tolerant candidate mutants. Of those, 4 mutants were further evaluated at water deficit conditions applied for 24 days after the first cutting at flowering bud stage. The results revealed that mutants determined as drought tolerant at germination stage were also tolerant to water deficit conditions. Protein content and superoxide dismutase values were found to be higher in all mutants than controls. Ascorbate peroxides, glutton reductase and lipid peroxidase values varied based on the mutant genotype and duration of drought stress. Drought stress significantly changed transcriptional levels of MtP5CS, MtDehyd, MseIF-2, MtRD2 and MsNAC genes. These results indicated that in vitro screening of alfalfa mutant seeds for osmatic tolerance at germination and early seedling growth stages was successfully able to determine the drought tolerant alfalfa mutants which were also tolerant to water deficit conditions after the first cutting at flowering bud stage.Öğe Kurağa Tolerant Yaygın Yonca (Medicago sativa) Genotiplerinin Geliştirilmesi(2019) Tiryaki, İskender; Acar, Okan; Sarı, UğurKuraklık dünya genelinde tarımsal üretimi tehdit eden en önemli abiyotik stres faktörlerinin başında gelmektedir. Ilıman iklim kuşağının en önemli bitkilerinden birisi olan yoncanın (Medicago sativa) sürdürülebilir tarıma sağladığı olumlu katkılar ve hayvan beslenmesindeki önemi, dünya ve ülkemizdeki kiymetini giderek artırmaktadır. Gelişimini tamamlamış 3-4 yıllık yonca bitkisi kurağa kısmen tolerant olmasına karşın özellikle çimlenme ve erken fide evreleri ile biçim sonrası dönemlerde meydana gelebilecek kuraklık stresinden büyük oranda etkilenmektedir. Çalışmada Ethyl methanesulphonate (EMS) mutajeni kullanılarak oluşturulan 340.675,0 adet M3 mutant yonca tohumu %35 lik PEG içeren in vitro şartlarda çimlenme ve erken fide evresinde kurağa tolerantlık açısından taranmıştır. Aseptik şartlarda kurağa tolerant olarak tespit edilen ve saksılarda çiçek tomurcuğu evresine kadar büyütülen 9 adet mutant, yoncanın su stresine karşı en hassas olduğu diğer bir gelişim evresi olan ilk biçim sonrası dönemde 24 gün süreyle gerçek kuraklık stresine maruz bırakılmıştır. Mutant ve kontrol bitkilerinin biçim sonrası kuraklık stresine verdikleri tepkiler bazı agro-morfolojik, fizyolojik ve moleküler parametreler kullanılarak belirlenmiştir. Çalışma sonuçları proje amaç ve hedeflerine uygun olarak çimlenme ve erken fide evresi ile ilk biçim sonrası yeniden büyüme dönemlerinde kuraklık stresini kontrol bitkilerine göre çok daha iyi tolere edebilen 7 mutant bitki genotipinin başarılı bir şekilde belirlendiğini göstermiştir.Öğe Kuraklık Stresi Altında Farklı Priming Uygulamalarının Buğdayda Çimlenme ve Fide Büyümesi Üzerine Etkileri(Çanakkale Onsekiz Mart Üniversitesi, 2022) Günay, Eda; Yıldız, Müge Teker; Acar, OkanBuğday (Triticum aestivum L.), kurak alanlarda yaygın olarak yetiştirilen bir tarım ürünüdür. Ancak kuraklık, dünya tarım alanlarında bitkisel üretim için en sınırlayıcı çevresel stres faktörlerinden biridir. Priming, çimlenmeden önce metabolik süreçleri iyileştirmek için tohum hidrasyonu ve kurutmayı içeren fizyolojik bir tekniktir. Bu çalışmanın amacı dört farklı priming uygulamasının (hormo-priming (gibberellik asit, GA3), redoks priming (hidrojen peroksit, H2O2), ozmo-priming (polietilen glikol, PEG) ve termo-priming (38oC)) kuraklık stresi altındaki yerel bir ekmeklik buğday çeşidinin (cv. Ekiz) çimlenme yüzdesi, sürgün-kök uzunluğu, toplam klorofil içeriği (SPAD), bağıl su içeriği (BSİ), spesifik yaprak alanı (SYA) ve H2O2 miktarı üzerine etkilerini belirlemektir. Kuraklık stresi, H2O2 içeriğini arttırırken tohum çimlenmesini, sürgün-kök uzunluklarını, SYA, SPAD ve BSİ'yi önemli ölçüde azaltmıştır. Termo-priming uygulamaları, kontrol bitkilerine kıyasla kuraklığın klorofil miktarı ve çimlenme üzerindeki olumsuz etkilerini tamamen iyileştirmiştir. Bununla birlikte, sürgün-kök uzunlukları, kontrol bitkilerinin sadece yarısı düzeyinde iyileşmiştir. Kuraklık stresi tohum çimlenmesini %14 oranında azaltırken, hormo-priming uygulaması tüm tohumların çimlenmesini sağlamıştır. Diğer priming uygulamalarının aksine, hormo-priming ve ozmo-priming uygulamaları BSİ'yi arttırmıştır. Sonuç olarak, kuraklık stresine dayanıklılıkta cv. Ekiz için termo-priming ve ozmo-priming uygulamaları diğer priming uygulamalarından daha etkili olduğu bulunmuşturÖğe Kuraklık stresi altındaki buğdayda eksojen Glisin Betain’in fizyolojik ve biyokimyasal etkileri(2020) Acar, Okan; Yıldız, Müge Teker; Günay, Eda; Baltacıer, GamzeKuraklık, bitki büyümesini ve verimini olumsuz etkileyen bir abiyotik stres faktörüdür. Buğday gibi tahıllar kuraklık stresinden olumsuz etkilendiklerinden verim azalmaktadır. İyi bir ozmo-tolerant olan Glisin-Betain (GB) ozmotik stres koşullarında eksojen olarak uygulandığında yaprak dokularına kolaylıkla alınır, kloroplastlarda fotosentetik aktivite ve zar bütünlüğünün sürdürülmesini sağlar ve membran zararını azaltır. Bu çalışmada 5 mM GB uygulamasının kuraklığa farklı toleransa sahip iki buğday çeşidinde (kurağa duyarlı Sultan-95, kurağa-dayanıklı Tosunbey) kök ve gövde uzunluğu, klorofil miktarı (SPAD), bağıl su içeriği, lipit peroksidasyon (TBARS), hücre zarı geçirgenliği (HZG), hidrojen peroksit (H2O2) ve antioksidan savunma sistemi enzim aktiviteleri (peroksidaz (POX), askorbat peroksidaz (APX), glutatyon redüktaz (GR), katalaz (CAT)) üzerine etkisi araştırılmıştır. Sonuçlarımıza göre, eksojen GB uygulaması ile her iki çeşit kuraklığa bağlı klorozisten ve kök uzunluğundaki inhibisyondan korunmuştur. Her iki çeşitte kuraklığa bağlı oksidatif stres nedeniyle TBARS ve H2O2 miktarının eksojen GB uygulamasıyla azaldığı belirlenmiştir. Oksidatif stresin bastırılmasında, H2O2 detoksifikasyonunun Tosunbey çeşidinde POX aktivitelerindeki artış ile Sultan- 95’te ise APX ve CAT aktivitelerindeki artış ile gerçekleştiği saptanmıştır. Sonuç olarak, eksojen GB uygulaması her iki buğday çeşidinde kuraklık stresiyle ortaya çıkan oksidatif zarardan korunma sağlamıştır.Öğe Kısır Yabani Yulaf Bitkisinde (Avena sterilis L.) Herbisit Direncinin Antioksidan Enzim Sistemiyle İlişkisinin Araştırılması(2016) Acar, OkanHerbisit kullanımı nedeniyle, dogal bitki populasyonlarında bu herbisitlere direnç dogrusal sekilde artmaktadır. Bitkilerde, ALS inhibitörleri ve Atrazin?den sonra en fazla herbisit direnci FOP grubu herbisitlere karsı gelismektedir. Avena sterilis L. bugday tarlalarında bu gruptan fenoxaprop herbisiti kullanılarak mu?cadele edilen bir yabancı ottur. Bu çalısmada fenoxaprop herbisitinin hassas ve dayanıklı iki kısır yabani yulaf populasyonunun pigment içerigi ve antioksidan savunma enzimleri ile PAL aktiviteleri arastırılmıstır. Marmara bölgesinden toplanan tohumlar Ege Üniversitesi Ziraat Faku?ltesi?nden saglanmıstır. Buna göre, dayanıklı bitkilerde önerilen dozda meydana gelen oksidatif stresin bastırılmasında SOD, POX, APX, GR ve CAT aktivitelerinin hassas bitkilere kıyasla daha yu?ksek oldugu belirlenmistir. Bununla birlikte, dayanıklı bitkilerdeki antioksidatif savunmanın önerilen dozun 4 katına kadar gelisebildigi de belirlenmistir. Sonuç olarak, hassas bitkilere kıyasla herbisite dayanıklı populasyona ait bitkilerin daha yu?ksek klorofil miktarına, daha yu?ksek antioksidan savunmaya ve daha yu?ksek PAL aktivitelerine sahip oldugu bulunmustur.Öğe Kızılbacak (Amaranthus retroflexus L.) Bitkisinde Kuraklık Toleransı ve Herbisit Direnci Arasındaki İlişkide Bazı Antioksidan Enzimlerin Rolünün Araştırılması(Türkiye Herboloji Derneği, 2020) Kurcan, Giray; Donat, Sevgi; Acar, OkanAbiyotik stresler bitkide morfolojik, fizyolojik, biyokimyasal ve moleküler değişiklikler yoluyla ürün verimini düşürür. Kuraklık stresi, hücredeki reaktif oksijen türlerinin (ROT) konsantrasyonlarını arttırarak hücredeki fosfolipidlere, proteinlere ve nükleik asitlere zarar verir, klorozla sonuçlanır. Yazlık bir yabancı ot olan kızılbacak (Amaranthus retroflexus L.) kuraklığa dayanıklı, tek yıllık ve otsu bir bitkidir. Yol kenarları, ekili alanlar ve meyve bahçelerinde yaygındır. 2,4-D, dicamba, mecoprop, bromoxynil, glifosat gibi herbisitler A. retroflexus üzerinde etkilidir. Ancak birçok çalışma bu türde herbisit direncinin geliştiğini bildirmektedir. Bu araştırma, kısa süreli kuraklık ve glyphosate’ın A. retroflexus’ta neden olduğu bazı fizyolojik ve biyokimyasal yanıtlara odaklanmıştır. Bu amaçla, 21 günlük A. retroflexus fidelerinin yaprak dokusunda toplam klorofil, toplam protein, lipit peroksidasyon (MDA), H2O2 (Hidrojen peroksit) miktarı, hücre zarı geçirgenliği (elektrolit sızıntısı), APX (Askorbat peroksidaz) ve GR (Glutatyon redüktaz) aktiviteleri belirlenmiştir. Kuraklık stresi ve glifosat A. retroflexus’ta H2O2 miktarını ve hücre zarı geçirgenliğini arttırmış ve kloroza neden olmuştur. Sonuçlarımız A. retroflexus’a glifosat uygulaması sonrasında yüksek ROT zararı ve düşük ROT temizleme aktivitesi olduğunu göstermiştir. Bu, antioksidan kapasite temelinde A. retroflexus’un glyphosate’a duyarlı olduğuna işaret etmektedir. Ayrıca bu araştırma ile A. retroflexus’ta kuraklık ve glyphosate’ın APX ve GR aktivitelerini nasıl etkilediği ilk defa gösterilmektedir. Sonuçta, A. retroflexus’ta oksidatif stresin kısa süreli kuraklığa kıyasla glifosat ile daha çok zarara neden olduğu saptanmıştırÖğe New Record for the East Mediterranean, Dardanelles (Turkey) and its Distribution: Polysiphonia morrowii Harvey (Ceramiales, Rhodophyta)(Central Fisheries Research Inst, 2009) Erdugan, Hueseyin; Akı, Cüneyt; Acar, Okan; Dural, Berrin; Aysel, VeyselIn this study, Polysiphonia morrowii Harvey was reported in the east Mediterranean and the coasts of Turkey for the first time.
