Yazar "Elbasan, Fevzi" seçeneğine göre listele
Listeleniyor 1 - 15 / 15
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Assessment of antioxidant system and enzyme/nonenzyme regulation related to ascorbate-glutathione cycle in ferulic acid-treated Triticum aestivum L. roots under boron toxicity(Tubitak Scientific & Technological Research Council Turkey, 2020) Ozfidan-Konakci, Ceyda; Yildiztugay, Evren; Elbasan, Fevzi; Yildiztugay, Aysegul; Kucukoduk, MustafaFerulic acid (FA; 3-methoxy-4-hydroxycinnamic acid) can eliminate stress-induced damage because of its ability to induce antioxidant activity under stress. The aim of this study was to identify the effects of FA on water status, antioxidant system, and lipid peroxidation in wheat (Triticum aestivum L.) roots exposed to boron (B) stress. Plants were grown in hydroponic culture containing the combination or alone form of 25-75 mu M FA and 4-8 mM B. Stress significantly decreased growth (RGR), water content (RWC), proline content (Pro), and osmotic potential (psi(H)). However, FA alleviated the decrease in RGR, RWC, and Pro content. Compared to the control groups, stress decreased the activities of superoxide dismutase (SOD), peroxidase (POX), catalase, and ascorbate peroxidase (APX), but an increase was only observed in glutathione reductase (GR) activity. Hydrogen peroxide (H2O2) content accumulated with B stress. Besides, a notable decrease was observed in the scavenging activity of hydroxyl radical (OH center dot); thus, wheat roots had high lipid peroxidation (thiobarbituric acid reactive substance content). In response to stress, FA triggered the activities of SOD, POX, and APX. Moreover, when FA was made present in stressed wheat roots, we observed the enhanced activities of dehydroascorbate reductase, and monodehydroascorbate reductase and dehydroascorbate contents which are related to ascorbate-glutathione cycle, so FA could maintain ascorbate (AsA) regeneration. However, when wheat roots were treated with stress, FA did not induce the regeneration of glutathione because of decline in GR activity. Due to successful elimination of H2O2 content, the exogenous application of FA alleviated B-induced lipid peroxidation in wheat. Consequently, FA eliminated the damage induced by B stress via the increased POX and the enzymes related to Asada-Halliwell pathway (AsA-GSH cycle) in wheat roots.Öğe The biphasic responses of nanomaterial fullerene on stomatal movement, water status, chlorophyll a fluorescence transient, radical scavenging system and aquaporin-related gene expression in Zea mays under cobalt stress(Elsevier, 2022) Ozfidan-Konakci, Ceyda; Arikan, Busra; Elbasan, Fevzi; Cavusoglu, Halit; Yildiztugay, Evren; Alp, Fatma NurNanomaterial fullerene (FLN) has different responses called the hormesis effect against stress conditions. The favorable/adverse impacts of hormesis on crop quality and productivity are under development in agrotechnology. In this study, the effect of FLN administration (100-250-500mg L-1 for FLN1-2-3, respectively) on growth, water management, gas exchange, chlorophyll fluorescence kinetics and cobalt (Co)-induced oxidative stress in Zea mays was investigated. The negative alterations in relative growth rate (RGR), water status (relative water content, osmotic potential and proline content) and gas exchange/stomatal regulation were removed by FLNs. FLNs were shown to protect photosynthetic apparatus and preserve the photochemistry of photosystems (PSI-PSII) in photosynthesis, chlorophyll fluorescence transients and energy flux damaged under Co stress. The maize leaves exposed to Co stress exhibited a high accumulation of hydrogen peroxide (H2O2) due to insufficient scavenging activity, which was confirmed by reactive oxygen species (ROS)-specific fluorescence visualization in guard cells. FLN regulated the gene expression of ribulose-1,5-bisphosphate carboxylase large subunit (rbcL), nodulin 26-like intrinsic protein1-1 (NIP1-1) and tonoplast intrinsic protein2-1 (TIP2-1) under stress. After stress exposure, FLNs successfully eliminated H2O2 content produced by superoxide dismutase (SOD) activity of catalase (CAT) and peroxidase (POX). The ascorbate (AsA) regeneration was achieved in all FLN applications together with Co stress through the elevated monodehydroascorbate reductase (MDHAR, under all FLNs) and dehydroascorbate reductase (DHAR, only FLN1). However, dose-dependent FLNs (FLN1-2) provided the induced pool of glutathione (GSH) and GSH redox state. Hydroponically applied FLNs removed the restrictions on metabolism and biological process induced by lipid peroxidation (TBARS content) and excessive ROS production. Considering all data, the modulation of treatment practices in terms of FLN concentrations and forms of its application will provide a unique platform for improving agricultural productivity and stress resistance in crops. The current study provided the first findings on the chlorophyll a fluorescence transient and localization of ROS in guard cells of Zea mays exposed to FLN and Co stress.Öğe Ex-foliar applied extremolyte ectoine improves water management, photosystem, antioxidant system and redox homeostasis in Zea mays under cadmium toxicity(Elsevier, 2022) Ozfidan-Konakci, Ceyda; Elbasan, Fevzi; Arikan, Busra; Alp, Fatma Nur; Yildiztugay, Evren; Keles, Ramazan; Kucukoduk, MustafaStress-protective osmolytes stabilize biomolecules and mediate plant defense responses, which help to remove the negative effects of stress in plants. However, the responses of ectoine (ECT, 1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid), as an osmolyte, need to be investigated for a better understanding of the defense pathways on water status, antioxidant system, and photosynthetic machinery against heavy metal stress. The different ECT concentrations (0.25-0.5 mM) were applied to Zea mays L. cv Karadeniz Yildizi with/without cadmium stress (100-200 mu M Cd). Stress caused an inhibition in growth (RGR), water content (RWC), and osmotic potential (Psi(pi)). After stress exposure, ECTs provided effective water management by elevating RGR, RWC and Psi(pi). The maize exposed to stress exhibited notable repression in the photosynthetic system depending on decreasing F-v/F-m, qP and, Phi(PSII) and increasing NPQ. The consumption of excess energy on photosynthetic machinery was controlled by ECTs via reversing these parameters. Cd toxicity resulted in downregulated-transcript levels of psbA, psbD, and psaB, which impaired the stability of PSI and PSII. After both Cd treatments, ECTs markedly induced the expression levels of psaA and psaB, which showed effective protection of photochemical activity. Cd-applied plants exhibited a decrease in superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), ascorbate peroxidase (APX), glutathione peroxidase (GPX), and glutathione reductase (GR), causing the accumulation of TBARS in lipid peroxidation. Under Cd+ECTs, SOD, glutathione S-transferase (GST) and POX had effective radical scavenging, thereby maintaining low contents of H2O2 and TBARS. ECTs alleviated the low Cd treatment-impaired redox state and participated in the ascorbate (AsA) and glutathione (GSH) regeneration. Consequently, ECT-mediated tolerance of maize was proved by increased growth, water potential, antioxidant capacity (especially SOD, POX), up-regulation of genes encoding proteins related to PSI, and PSII and AsA-GSH redox systems under Cd toxicity. (c) 2021 Published by Elsevier B.V. on behalf of SAAB.Öğe The exogenous application of naringenin and rosmarinic acid modulates functional traits in Lepidium sativum(Wiley, 2023) Salehi, Hajar; Zhang, Leilei; Alp-Turgut, Fatma Nur; Arikan, Busra; Elbasan, Fevzi; Ozfidan-Konakci, Ceyda; Balci, MelikeBACKGROUND: Phenolic modulators have attracted attention for their potential in shaping functional traits in plants. This work investigated the impact of naringenin (Nar) and rosmarinic acid (RA) on the functional properties of Lepidium sativum leaves and roots.Results: Untargeted metabolomics identified a diverse phenolic profile, including flavonoids, phenolic acids, low molecular weight phenolics, lignans, and stilbenes. Cluster, analysis of variance multiblock orthogonal partial least squares (AMOPLS), and orthogonal projection to latent structures discriminant analysis (OPLS-DA) multivariate analyses confirmed tissue-specific modulation of bioactive compounds. The tissue was the hierarchically most influential factor, explaining 27% of observed variability, while the treatment and their interaction were statistically insignificant. Thereafter, various in vitro assays were employed to assess antioxidant capacity, including 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2 '-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radical scavenging activity, cupric ion reducing antioxidant capacity (CUPRAC), and ferric ion reducing antioxidant power (FRAP), metal chelating ability, and phosphomolybdenum (PMD) assays. Extracts were also tested for inhibitory effects on cholinesterase, amylase, glucosidase, and tyrosinase enzymes. RA application positively impacted antioxidant and enzyme inhibitory activities, holding valuable implications in shaping the health-promoting properties of L. sativum.Conclusion: The untargeted metabolomics analysis showed a significant tissue-dependent modulation of bioactive compounds, determining no synergistic effect between applying phenolic compounds in combination. Specifically, the sole application of RA increased anthocyanins and hydroxyphenyl propanoic acid content on leaves, which was strictly related to enhancing the biological activities.(c) 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.Öğe Exogenous hesperidin and chlorogenic acid alleviate oxidative damage induced by arsenic toxicity in Zea mays through regulating the water status, antioxidant capacity, redox balance and fatty acid composition(Elsevier Sci Ltd, 2022) Arikan, Busra; Ozfidan-Konakci, Ceyda; Yildiztugay, Evren; Zengin, Gokhan; Alp, Fatma Nur; Elbasan, FevziArsenic (As) toxicity is a problem that needs to be solved in terms of both human health and agricultural production in the vast majority of the world. The presence of As causes biomass loss by disrupting the balance of biochemical processes in plants and preventing growth/water absorption in the roots and accumulating in the edible parts of the plant and entering the food chain. A critical method of combating As toxicity is the use of biosafe, natural, bioactive compounds such as hesperidin (HP) or chlorogenic acid (CA). To this end, in this study, the physiological and biochemical effects of HP (100 mu M) and CA (50 mu M) were investigated in Zea mays under arsenate stress (100 mu M). Relative water content, osmotic potential, photosynthesis-related parameters were suppressed under stress. It was determined that stress decreased the activities of the antioxidant system and increased the level of saturated fatty acids and, gene expression of PHT transporters involved in the uptake and translocation of arsenate. After being exposed to stress, HP and CA improved the capacity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), glutathione S-transferase (GST) and glutathione peroxidase (GPX) and then ROS accumulation (H2O2) and lipid peroxidation (TBARS) were effectively removed. These phenolic compounds contributed to maintaining the cellular redox status by regulating enzyme/non-enzyme activity/contents involved in the AsA-GSH cycle. HP and CA reversed the adverse effects of excessive metal ion accumulation by re-regulated expression of the PHT1.1 and PHT1.3 genes in response to stress. Exogenously applied HP and CA effectively maintained membrane integrity by regulating saturated/unsaturated fatty acid content. However, the combined application of HP and CA did not show a synergistic protective activity against As stress and had a negative effect on the antioxidant capacity of maize leaves. As a result, HP and CA have great potentials to provide tolerance to maize under As stress by reducing oxidative injury and preserving the biochemical reactions of photosynthesis.Öğe Fe2O3-modified graphene oxide mitigates nanoplastic toxicity via regulating gas exchange, photosynthesis, and antioxidant system in Triticum aestivum(Pergamon-Elsevier Science Ltd, 2022) Arikan, Busra; Alp, Fatma Nur; Ozfidan-Konakci, Ceyda; Balci, Melike; Elbasan, Fevzi; Yildiztugay, Evren; Cavusoglu, HalitThe ever-increasing plastic pollution in soil and water resources raises concerns about its effects on terrestrial plants and agroecosystems. Although there are many reports about the contamination with nanoplastics on plants, the presence of magneto-assisted nanomaterials enabling the removal of their adverse impacts still re-mains unclear. Therefore, the purpose of the current study is to evaluate the potential of nanomaterial Fe2O3- modified graphene oxide (FGO, 50-250 mg L-1) to eliminate the adverse effects of nanoplastics in plants. Wheat plants exposed to polystyrene nanoplastics concentrations (PS, 10, 50 and 100 mg L-1) showed decreased growth, water content and loss of photosynthetic efficiency. PS toxicity negatively altered gas exchange, antenna structure and electron transport in photosystems. Although the antioxidant system was partially activated (only superoxide dismutase (SOD), NADPH oxidase (NOX) and glutathione reductase (GR)) in plants treated with PS, it failed to prevent PS-triggered oxidative damage, as showing lipid peroxidation and hydrogen peroxide (H2O2) levels. FGOs eliminated the adverse impacts of PS pollution on growth, water status, gas exchange and oxidative stress markers. In addition, FGOs preserve the biochemical reactions of photosynthesis by actively increasing chlorophyll fluorescence parameters in the stressed-wheat leaves. The activities of all enzymatic antioxidants increased, and the H2O2 and TBARS contents decreased. GSH-mediated detoxifying antioxidants such as gluta-thione S-transferase (GST) and glutathione peroxidase (GPX) were stimulated by FGOs against PS pollution. FGOs also triggered the enzymes and non-enzymes related to the Asada-Halliwell cycle and protected the regeneration of ascorbate (AsA) and glutathione (GSH). Our findings indicated that FGO had the potential to mitigate nanoplastic-induced damage in wheat by regulating water relations, protecting photosynthesis reactions and providing efficient ROS scavenging with high antioxidant capacity. This is the first report on removing PS -induced damage by FGO applications in wheat leaves.Öğe Glutamate, Humic Acids and Their Combination Modulate the Phenolic Profile, Antioxidant Traits, and Enzyme-Inhibition Properties in Lettuce(Mdpi, 2023) De Gregorio, Marco Armando; Zengin, Gokhan; Alp-Turgut, Fatma Nur; Elbasan, Fevzi; Ozfidan-Konakci, Ceyda; Arikan, Busra; Yildiztugay, EvrenLettuce (Lactuca sativa L., Asteraceae) is a popular vegetable leafy crop playing a relevant role in human nutrition. Nowadays, novel strategies are required to sustainably support plant growth and elicit the biosynthesis of bioactive molecules with functional roles in crops including lettuce. In this work, the polyphenolic profile of lettuce treated with glutamic acid (GA), humic acid (HA), and their combination (GA + HA) was investigated using an untargeted metabolomics phenolic profiling approach based on high-resolution mass spectrometry. Both aerial and root organ parts were considered, and a broad and diverse phenolic profile could be highlighted. The phenolic profile included flavonoids (anthocyanins, flavones, flavanols, and flavonols), phenolic acids (both hydroxycinnamics and hydroxybenzoics), low molecular weight phenolics (tyrosol equivalents), lignans and stilbenes. Overall, GA and HA treatments significantly modulated the biosynthesis of flavanols, lignans, low molecular weight phenolics, phenolic acids, and stilbene. Thereafter, antioxidant capacity was evaluated in vitro with 2,2-diphenyln-1-picrylhydrazyl (DPPH), 2,2'-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), and cupric ion reducing antioxidant capacity (CUPRAC) assays. In addition, this study examined the inhibitory properties of enzymes, including acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), tyrosinase, alpha-amylase, and alpha-glucosidase. Compared to individual treatments, the combination of GA + HA showed stronger antioxidant abilities in free radical scavenging and reducing power assays in root samples. Moreover, this combination positively influenced the inhibitory effects of root samples on AChE and BChE and the tyrosinase inhibitory effect of leaf samples. Concerning Pearson's correlations, antioxidant and enzyme inhibition activities were related to phenolic compounds, and lignans in particular correlated with radical scavenging activities. Overall, the tested elicitors could offer promising insights for enhancing the functional properties of lettuce in agricultural treatments.Öğe The hormetic dose-risks of polymethyl methacrylate nanoplastics on chlorophyll a fluorescence transient, lipid composition and antioxidant system in Lactuca sativa(Elsevier Sci Ltd, 2022) Yildiztugay, Evren; Ozfidan-Konakci, Ceyda; Arikan, Busra; Alp, Fatma Nur; Elbasan, Fevzi; Zengin, Gokhan; Cavusoglu, HalitNanoplastic pollution has become an increasing problem due to over-consumption and degradation in ecosystems. A little is known about ecological toxicity and the potential risks of nanoplastics on plants. To better comprehend the hormetic effects of nanoplastics, the experimental design was conducted on the impacts of polymethyl methacrylate (PMMA) on water status, growth, gas exchange, chlorophyll a fluorescence transient, reactive oxygen species (ROS) content (both content and fluorescence visualization), lipid peroxidation and antioxidant capacity (comparatively between leaves and roots). For this purpose, PMMA (10, 20, 50 and 100 mg L-1) was hydroponically applied to Lactuca sativa for 15 days(d). PMMA exposure resulted a decline in the growth, water content and osmotic potential. As based on assimilation rate (A), stomatal conductance (g(s)), and intercellular CO2 concentrations (C-i), the decreased stomatal limitation (L-s) and, A/C-i and increased intrinsic mesophyll efficiency proved low carboxylation efficiency showing impaired photosynthesis as a non-stomatal limitation. PMMA toxicity increased the trapping fluxes and absorption with a decrease in electron transport fluxes caused the disruption in reaction centers of photosystems. The leaves and roots had a similar effect against PMMA toxicity, with increased superoxide dismutase (SOD) activity. Although, catalase (CAT) and peroxidase (POX) of leaves increased under 10 mg L-1 PMMA, these defense activities failed to prevent radicals from attacking. Compared to the leaves, the lettuce roots showed an intriguing result for AsA-GSH cycle against PMMA exposure. In the roots, the lowest PMMA application provided the high ascorbate/dehydroascorbate (AsA/DHA), GSH/GSSG and the pool of AsA/glutathione (GSH) and non-suppressed GSH redox state. Also, 10 mg L-1 PMMA helped remove high hydrogen peroxide (H2O2) by both glutathione peroxidase (GPX) and glutathione S-transferase (GST). Since this improvement in the antioxidant system could not be continued in roots after higher applications than 20 mg L-1 PMMA, TBARS (Thiobarbituric acid-reactive substances), indicating the level of lipid peroxidation, and H2O2 increased. Our findings obtained from PMMA-applied lettuce provide new information to advance the tolerance mechanism against nanoplastic pollution.Öğe Hydrogen sulfide (H2S) and nitric oxide (NO) alleviate cobalt toxicity in wheat (Triticum aestivum L.) by modulating photosynthesis, chloroplastic redox and antioxidant capacity(Elsevier, 2020) Ozfidan-Konakci, Ceyda; Yildiztugay, Evren; Elbasan, Fevzi; Kucukoduk, Mustafa; Turkan, IsmailThe role of hydrogen sulfide (H2S)/nitric oxide (NO) in mitigating stress-induced damages has gained interest in the past few years. However, the protective mechanism H2S and/or NO has towards the chloroplast system through the regulation of redox status and activation of antioxidant capacity in cobalt-treated wheat remain largely unanswered. Triticum aestivum L. cv. Ekiz was treated with alone/in combination of a H2S donor (sodium hydrosulfide (NaHS,600 mu M)), a NO donor (sodium nitroprusside (SNP,100 mu M)) and a NO scavenger (rutin hydrate (RTN,50 mu M)) to assess how the donors affect growth, water relations, redox and antioxidant capacity in chloroplasts, under cobalt (Co) concentrations of 150-300 mu M. Stress decreased a number of parameters (growth, water content (RWC), osmotic potential (psi(Pi)), carbon assimilation rate, stomatal conductance, intercellular CO2 concentrations, transpiration rate and the transcript levels of rubisco, which subsequently disrupt the photosynthetic capacity). However, SNP/NaHS counteracted the negative effects of stress on these aforementioned parameters and RTN application with stress/non-stress was reversed these effects. Hydrogen peroxide (H2O2) and TBARS were induced under stress in spite of activated ascorbate peroxidase (APX). SNP/NaHS under stress increased activation of superoxide dismutase (SOD), peroxidase (POX), APX, glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), ascorbate (tAsA) and glutathione (GSH). In conclusion, NaHS/SNP are involved in the regulation and modification of growth, water content, rubisco activity and up-regulation of ascorbate-glutathione cycle (AsA-GSH) in chloroplast under stress.Öğe Hydrogen Sulfide Protects Damage From Methyl Viologen-Mediated Oxidative Stress by Improving Gas Exchange, Fluorescence Kinetics of Photosystem II, and Antioxidant System in Arabidopsis thaliana(Springer, 2023) Ozfidan-Konakci, Ceyda; Yildiztugay, Evren; Arikan, Busra; Elbasan, Fevzi; Alp, Fatma Nur; Kucukoduk, MustafaConsidering the unfavorable impacts of methyl viologen-induced oxidative stress (MV1-2, 50 and 500 mu M) on growth, gas exchange (intercellular CO2 concentration, carbon assimilation rate, stomatal conductance, transpiration rate), the efficiency of PSII photochemistry and gene expressions of proteins related to photosystems, antioxidant capacity, and the content/histochemical staining of reactive oxygen species (ROS) markers, the experiment was conducted to evaluate the possible mechanisms of sodium hydrosulfide hydrate (a hydrogen sulfide donor, 500 mu M NaHS) and its scavenger/inhibitor (hypotaurine, 50 mu M and hydroxylamine, 100 mu M) in Arabidopsis thaliana for 24 h. NaHS alleviated stress-reduced growth (4.2-fold increase for MV2 + NaHS) and improved the gas exchange parameters. NaHS was capable of improving the photosynthetic ability under 50 mu M MV through sustaining photochemical activity in PSII and photochemical conversion efficiency as evident by transcript levels of psbA, psbD, psaA, and psaB. Stress-caused oxidative damage was scavenged by POX (a 90% increase). However, this action was not enough, suggested by increased ROS accumulation, lipid peroxidation (a 165% induction) and lipoxygenase activity (2.4-fold increase), and loss of membrane integrity. Meanwhile, NaHS successfully eliminated these responses against MV, evidenced by weak histochemical staining of ROS and lesser lipid peroxidation and membrane damage. The synchronized activities of both SOD and CAT triggered by NaHS were responsible for decreasing H2O2 content (by 57.4% decrease for MV2 + NaHS) in response to MV stress. After stress exposure, NaHS utilized the ascorbate-glutathione (AsA-GSH) cycle for removing H2O2. Arabidopsis subjected to MV1 plus NaHS exhibited the advanced levels of AsA regeneration (by 15.3% increase) and the redox state of GSH. Interestingly, NaHS under the high MV concentration did not maintain the re-establishment of GSH homeostasis and redox state of GSH in spite of the induced AsA/DHA (dehydroascorbate). NaHS could protect Arabidopsis from oxidative stress, likely by regulating growth, gas exchange, and photosynthetic performance, inducing expression levels of genes associated with photosystems and regulating antioxidant capacity, and redox balance for AsA and GSH.Öğe Influences of sulfonated graphene oxide on gas exchange performance, antioxidant systems and redox states of ascorbate and glutathione in nitrate and/or ammonium stressed-wheat (Triticum aestivum L.)(Royal Soc Chemistry, 2021) Ozfidan-Konakci, Ceyda; Yildiztugay, Evren; Cavusoglu, Halit; Arikan, Busra; Elbasan, Fevzi; Kucukoduk, Mustafa; Turkan, IsmailGraphene oxide has unique physiochemical properties and a large surface area. After functionalization, its shape, surface, adsorption capacity, and toxicity levels can change. The potential impacts of sulfonated graphene oxide (SGO, modified with the sulfonic group) on metabolic processes and biological pathways are unanswered questions concerning NO3- or NH4+ toxicity. To fill this gap of knowledge, in the present study, SGO (50-250-500 mg L-1) was applied to Triticum aestivum cv. Ekiz with/without 140 mM nitrate (NS stress) and 5 mM ammonium (AS stress). Both stress treatments suppressed the growth, water content, osmotic potential, and photosynthetic capacity, as detected by a decrease in the carbon assimilation rate (A), stomatal conductance (g(s)), intercellular CO2 concentration (C-i), and transpiration rate (E), and an increase in stomatal limitation. After stress exposure, SGO provided positive responses to these parameters. There were different responses in the antioxidant system under stress: superoxide dismutase (SOD) and peroxidase (POX) under NS stress; SOD, catalase (CAT) and POX under AS and NS + AS stresses. However, hydrogen peroxide (H2O2) and lipid peroxidation increased because lack of effective antioxidant activation. In response to NS or AS, SGO successfully regulated SOD, CAT, glutathione peroxidase (GPX) and the enzyme/non-enzymes related to the AsA-GSH cycle, attenuating the high levels of H2O2, lipoxygenase (LOX) and TBARS-based damage. Along with the antioxidant system, SGO controlled the contents of NO3- or NH4+ by regulation of NPF6.3 and AMT1.2 genes. Interestingly, under NS plus AS, the alleviation action of SGO varied in a concentration-dependent manner: (i) low SGO concentration (50 mg L-1) protected the regeneration of ascorbate (AsA) and glutathione (GSH) and the high activities of GST and GPX; (ii) 250 mg L-1 SGO maintained the GSH redox state and the induced activity of glutathione S-transferase (GST); (iii) the highest SGO concentration (500 mg L-1) did not eliminate H2O2 accumulation, which coincided with the increased levels of TBARS and LOX. The toxicity of the high SGO concentration was further increased in wheat with non-stress or NS plus AS stresses. Our findings specified that the damage stimulated by NS and/or AS stress was removed by SGO applications through the increased antioxidant activity and gas exchange parameters, resulting in the protection of the redox state.Öğe Metabolomics and Physiological Insights into the Ability of Exogenously Applied Chlorogenic Acid and Hesperidin to Modulate Salt Stress in Lettuce Distinctively(Mdpi, 2021) Zhang, Leilei; Miras-Moreno, Begona; Yildiztugay, Evren; Ozfidan-Konakci, Ceyda; Arikan, Busra; Elbasan, Fevzi; Ak, GunesRecent studies in the agronomic field indicate that the exogenous application of polyphenols can provide tolerance against various stresses in plants. However, the molecular processes underlying stress mitigation remain unclear, and little is known about the impact of exogenously applied phenolics, especially in combination with salinity. In this work, the impacts of exogenously applied chlorogenic acid (CA), hesperidin (HES), and their combination (HES + CA) have been investigated in lettuce (Lactuca sativa L.) through untargeted metabolomics to evaluate mitigation effects against salinity. Growth parameters, physiological measurements, leaf relative water content, and osmotic potential as well as gas exchange parameters were also measured. As expected, salinity produced a significant decline in the physiological and biochemical parameters of lettuce. However, the treatments with exogenous phenolics, particularly HES and HES + CA, allowed lettuce to cope with salt stress condition. Interestingly, the treatments triggered a broad metabolic reprogramming that involved secondary metabolism and small molecules such as electron carriers, enzyme cofactors, and vitamins. Under salinity conditions, CA and HES + CA distinctively elicited secondary metabolism, nitrogen-containing compounds, osmoprotectants, and polyamines.Öğe Multi-Walled Carbon Nanotubes Influence on Gas Exchange, Redox Reaction and Antioxidant System in Zea mays Exposed to Excessive Copper(Springer, 2022) Alp, Fatma Nur; Ozfidan-Konakci, Ceyda; Yildiztugay, Evren; Arikan, Busra; Elbasan, Fevzi; Ozmen, Mustafa; Kucukoduk, MustafaThe carbon nanotube is one of the most encouraging tools in nanotechnology. However, the extent and interaction with different plant systems of multi-wall carbon nanotubes (MWCNT) are not fully understood under stress conditions. The present study aimed to evaluate the potential of MWCNT to improve tolerance to copper toxicity in maize (Zea mays). For this purpose, Zea mays was grown under exposure to exogenously applied MWCNT concentrations (50-100-250 mg L-1), individually or combined, with 50 mu M copper (Cu stress) for 7 days. MWCNTs eliminated the adverse effects caused by stress on water status, gas parameters and osmotic potential state. Although stress activated the antioxidant system, reactive oxygen species (ROS) accumulation (hydrogen peroxide (H2O2) content) and lipid peroxidation (TBARS) increased because stress-applied maize was unable to perform an effective scavenging action. MWCNT applications had a strong ROS scavenging effect on maize seedlings. Under Cu stress, there were different responses on antioxidant capacity depending on MWCNT concentrations called the hormesis effect. Under stress, M50-M100 (50 and 100 mg L-1) reversed the radical accumulation by providing increased superoxide dismutase (SOD), glutathione peroxidase (GPX) and the regeneration of ascorbate (AsA) and glutathione (GSH). The MWCNT-activated enzyme system maintained the low levels of H2O2 and TBARS contents against stress. However, after the highest MWCNT concentration (250 mg L-1) plus stress exposure, this trend could not be continued, as by represented the disrupted antioxidant capacity and the reduced AsA/DHA and GSH redox state in maize seedlings. Therefore, the levels of H2O2 and TBARS were similar to the stress ones. Our findings indicated that MWCNT provided a new potential tool against Cu stress to improve the stress tolerance mechanism in maize.Öğe Nanomaterial sulfonated graphene oxide advances the tolerance against nitrate and ammonium toxicity by regulating chloroplastic redox balance, photochemistry of photosystems and antioxidant capacity in Triticum aestivum(Elsevier, 2022) Yildiztugay, Evren; Ozfidan-Konakci, Ceyda; Cavusoglu, Halit; Arikan, Busra; Alp, Fatma Nur; Elbasan, Fevzi; Kucukoduk, MustafaThe current study was designed to assess nanomaterial sulfonated graphene oxide (SGO) potential in improving tolerance of wheat chloroplasts against nitrate (NS) and ammonium (AS) toxicity. Triticum aestivum cv. Ekiz was grown under SGOs (50-250-500 mg L-1) with/without 140 mM NS and 5 mM AS stress. SGOs were eliminated the adverse effects produced by stress on chlorophyll fluorescence, potential photochemical efficiency and physiological state of the photosynthetic apparatus. SGO reversed the negative effects on these parameters. Upon SGOs exposure, the induced expression levels of photosystems-related reaction center proteins were observed. SGOs reverted radical accumulation triggered by NS by enabling the increased superoxide dismutase (SOD) activity and ascorbate (AsA) regeneration. Under AS, the turnover of both AsA and glutathione (GSH) was maintained by 50-250 mg L-1 SGO by increasing the enzymes and non-enzymes related to AsA-GSH cycle. 500 mg L-1 SGO prevented the radical over-accumulation produced by AS via the regeneration of AsA and peroxidase (POX) activity rather than GSH regeneration. 50-250 mg L-1 SGO protected from the NS+AS-induced disruptions through the defense pathways connected with AsA-GSH cycle represented the high rates of AsA/DHA and, GSH/GSSG and GSH redox state. Our findings specified that SGO to NS and AS-stressed wheat provides a new potential tool to advance the tolerance mechanism.Öğe Rare-earth element scandium improves stomatal regulation and enhances salt and drought stress tolerance by up-regulating antioxidant responses of Oryza sativa(Elsevier France-Editions Scientifiques Medicales Elsevier, 2020) Elbasan, Fevzi; Ozfidan-Konakci, Ceyda; Yildiztugay, Evren; Kucukoduk, MustafaOryza sativa L. cv. Gonen grown in hydroponic culture was treated with scandium (Sc; 25 and 50 mu M) alone or in combination with salt (100 mM NaCl) and/or drought (5% PEG-6000). Stress caused a decrease in growth (RGR), water content (RWC), osmotic potential (Psi(Pi)), chlorophyll fluorescence (F-v/F-m) and potential photochemical efficiency (F-v/F-o). Sc application prevented the decreases of these parameters. Sc also alleviated the changes on gas exchange parameters (carbon assimilation rate (A), stomatal conductance (g(s)), intercellular CO2 concentrations (C-i), transpiration rate (E) and stomatal limitation (L-s)). Stress caused no increase in superoxide dismutase (SOD) activity. After induvial applied NaCl or PEG, catalase (CAT) and ascorbate peroxidase (APX) showed an enhancement in activation and tried to scavenge of hydrogen peroxide (H(2)o(2)). On the other hand, in plants with the combination form of NaCl and PEG, only CAT activity was induced. Sc applications to NaCl-treated rice led to an increase of SOD, APX, glutathione reductase (GR), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR) as well as peroxidase (PDX). Sc under NaCl could be maintained both ascorbate (AsA) and glutathione (GSH) regeneration. Despite of induction of MDHAR and DHAR under Sc plus PEG, Sc did not maintain AsA redox state because of no induction in APX activity. However, GSH pool could be regenerated by induction in DHAR and GR in this group. Sc application (especially for 25 mu M) in rice exposed to NaCl + PEG resulted an enhancement in APX and MDHAR and so Sc could be partially provided AsA regeneration. Since no increases in DHAR and GR were observed, GSH pool was reduced. Due to this activation of antioxidant enzymes, stress-induced H2O2 and TBARS content (lipid peroxidation) significantly decreased in rice with Sc applications. Sc in plants with stress also increased the transcript levels of OsCDPK7 and OsBG1 related to stomatal movement and signaling pathway. Consequently, Sc protected the rice plants by minimizing disturbances caused by NaCl or PEG exposure via the AsA-GSH redox-based systems.
