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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 The effects of fullerene on photosynthetic apparatus, chloroplast-encoded gene expression, and nitrogen assimilation in Zea mays under cobalt stress(Wiley, 2022) Ozfidan-Konakci, Ceyda; Alp, Fatma Nur; Arikan, Busra; Balci, Melike; Parmaksizoglu, Zeynep; Yildiztugay, Evren; Cavusoglu, HalitCarbon nanostructures, such as the water-soluble fullerene (FLN) derivatives, are considered perspective agents for agriculture. FLN can be a novel nano-agent modulating plant response against stress conditions. However, the mechanism underlying the impacts of FLN on plants in agroecosystems remains unclear. Zea mays was exposed to exogenous C-60-FLN applications (FLN1: 100; FLN2: 250; and FLN3: 500 mg L-1) with/without cobalt stress (Co, 300 mu M) for 3 days (d). In the maize chloroplasts, Co stress disrupted the photosynthetic efficiency and the expression of genes related to the photosystems (psaA and psbA). FLNs effectively improved the efficiency and photochemical reaction of photosystems. Co stress induced the accumulation of reactive oxygen species (ROS) as confirmed by ROS-specific fluorescence in guard cells. Co stress increased only chloroplastic superoxide dismutase (SOD) and peroxidase (POX). Stress triggered oxidative damages in maize chloroplasts, measured as an increase in TBARS content. In Co-stressed seedlings exposed to FLN1 and FLN2 exposures, the hydrogen peroxide (H2O2) was scavenged through the nonenzymes/enzymes-related to the AsA-GSH cycle by preserving ascorbate (AsA) conversion, as well as GSH/GSSG and glutathione (GSH) redox state. Also, the alleviation effect of FLN3 against stress could be attributed to increased glutathione S-transferase (GST) activity and AsA regeneration. FLN applications reversed the inhibitory effects of Co stress on nitrogen assimilation. In maize chloroplasts, FLN increased the activities of nitrate reductase (NR), glutamate dehydrogenase (GDH), nitrite reductase (NiR), and glutamine synthetase (GS), which provided conversion of inorganic nitrogen (N) into organic N. The ammonium (NH4+) toxicity was removed via GS and GDH but not glutamate synthase (GOGAT). The increased NAD-GDH (deaminating) and NADH-GDH (aminating) activities indicated that GDH was needed more for NH4+ detoxification. Therefore, FLN exposure to Co-stressed maize plants might play a role in N metabolism regarding the partitioning of N assimilates. Exogenous FLN conceivably removed Co toxicity by improving the expressions of genes related to reaction center proteins of photosystems, increasing the level of enzymes related to the defense system, and improving the N assimilation in maize chloroplasts.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 Graphene oxide-based aerogel stimulates growth, mercury accumulation, photosynthesis-related gene expression, antioxidant efficiency and redox status in wheat under mercury exposure(Elsevier Sci Ltd, 2024) Alp-Turgut, Fatma Nur; Ozfidan-Konakci, Ceyda; Arikan, Busra; Comak, Gurbuz; Yildiztugay, EvrenMercury (Hg) pollution is a global concern in cropland systems. Hg contamination causes a disruption in the growth, energy metabolism, redox balance, and photosynthetic activity of plants. In the removal of Hg toxicity, a recent critical strategy is the use of aerogels with biodegradability and biocompatibility. However, it is unknown how graphene oxide-based aerogels stimulate the defense systems in wheat plants exposed to Hg toxicity. Therefore, in this study, the photosynthetic, genetic, and biochemical effects of reduced graphene oxide aerogel treatments (gA; 50-100-250 mg L-1) were examined in wheat (Triticum aestivum) under Hg stress (50 mu M HgCl2). The relative growth rate (RGR) significantly decreased (84%) in response to Hg stress. However, the reduced RGR and water relations (RWC) of wheat were improved by gA treatments. The impaired gas exchange levels (stomatal conductance, carbon assimilation rate, intercellular CO2 concentrations, and transpiration rate) caused by stress were reversed under Hg plus gAs. Additionally, stress hampered chlorophyll fluorescence (F-v/F-o, F-v/F-m), and under Hg toxicity the expression of psaA genes was reduced (>0.4-fold), but psaB gene was significantly up-regulated (>3-fold) which are the genes involved in PSI. By increasing expression patterns of both genes relating to PSI, gAs reversed the adverse consequences on F-v/F-o and F-v/F-m in the presence of excessive Hg concentration. The activities of glutathione S-transferase (GST), glutathione reductase (GR), catalase (CAT), ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR) decreased under Hg toxicity. On the other hand, the activities of superoxide dismutase (SOD), APX, GST, and glutathione peroxidase (GPX) increased following gA treatments against stress, leading to the successful elimination of toxic levels of H2O2 and lipid peroxidation (TBARS content) by decreasing the levels by about 30%, and 40%, respectively. By modulating enzyme/non-enzyme activity/contents including the AsA-GSH cycle, gAs contributed to the protection of the cellular redox state. Most important of all, gA applications were able to reduce Hg intake by approximately 66%. Therefore, these results showed that gAs were effective in highly inhibiting Hg uptake and could significantly increase wheat tolerance to toxicity by eliminating Hg-induced oxidative damage and inhibiting metabolic processes involved in photosynthesis. The findings obtained from the study provide a new perspective on the alleviation roles of reduced graphene oxide aerogels as an effective adsorbent for decreasing damages of mercury toxicity in wheat plants.Öğe Halotolerant plant growth-promoting bacteria, Bacillus pumilus, modulates water status, chlorophyll fluorescence kinetics and antioxidant balance in salt and/or arsenic-exposed wheat(Academic Press Inc Elsevier Science, 2023) Ozfidan-Konakci, Ceyda; Arikan, Busra; Alp-Turgut, Fatma Nur; Balci, Melike; Uysal, Ahmet; Yildiztugay, EvrenSeed priming is an effective and novel technique and the use of eco-friendly biological agents improves the physiological functioning in the vegetative stage of plants. This procedure ensures productivity and acquired stress resilience in plants against adverse conditions without contaminating the environment. Though the mechanisms of bio-priming-triggered alterations have been widely explained under induvial stress conditions, the interaction of combined stress conditions on the defense system and the functionality of photosynthetic apparatus in the vegetative stage after the inoculation to seeds has not been fully elucidated. After Bacillus pumilus inoculation to wheat seeds (Triticum aestivum), three-week-old plants were hydroponically exposed to the alone and combination of salt (100 mM NaCl) and 200 mu M sodium arsenate (Na2HAsO4 center dot 7H(2O), As) for 72 h. Salinity and As pollutant resulted in a decline in growth, water content, gas exchange parameters, fluorescence kinetics and performance of photosystem II (PSII). On the other hand, the seed inoculation against stress provided the alleviation of relative growth rate (RGR), relative water content (RWC) and chlorophyll fluorescence. Since there was no effective antioxidant capacity, As and/or salinity caused the induction of H2O(2) accumulation and thiobarbituric acid reactive substances content (TBARS) in wheat. The inoculated seedlings had a high activity of superoxide dismutase (SOD) under stress. B. pumilis decreased the NaCl-induced toxic H2O2 levels by increasing peroxidase (POX) and enzymes/non-enzymes related to ascorbate-glutathione (AsA-GSH) cycle. In the presence of As exposure, the inoculated plants exhibited an induction in CAT activity. On the other hand, for H2O2 scavenging, the improvement in the AsA-GSH cycle was observed in bacterium priming plants plus the combined stress treatment. Since B. pumilus inoculation reduced H2O2 levels against all stress treatments, lipid peroxidation subsequently decreased in wheat leaves. The findings obtained from our study explained that the seed inoculation with B. pumilus provided an activation in the defense system and protection in growth, water status, and gas exchange regulation in wheat plants against the combination of salt and As.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 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 The impacts of nanoplastic toxicity on the accumulation, hormonal regulation and tolerance mechanisms in a potential hyperaccumulator - Lemna minor L.(Elsevier, 2022) Arikan, Busra; Alp, Fatma Nur; Ozfidan-Konakci, Ceyda; Yildiztugay, Evren; Turan, Metin; Cavusoglu, HalitPlastic pollution, which is currently one of the most striking problems of our time, raises concerns about the dispersal of micro and nano-sized plastic particles in ecosystems and their toxic effects on living organisms. This study was designed to reveal the toxic effects of polystyrene nanoplastic (PS NP) exposure on the freshwater macrophyte Lemna minor. In addition, elucidating the interaction of this aquatic plant, which is used extensively in the phytoremediation of water contaminants and wastewater treatment facilities, with nanoplastics will guide the development of remediation techniques. For this purpose, we examined nanoplastic accumulation, oxidative stress markers, photosynthetic efficiency, antioxidant system activity and phytohormonal changes in L. minor leaves subjected to PS NP stress (P-1, 100 mg L-1; P-2, 200 mg L-1 PS NP). Our results showed no evidence of PS NP-induced oxidative damage in P-1 group plants, although PS NP accumulation reached 56 mu g g(-1) in the leaves. Also, no significant changes in chlorophyll a fluorescence parameters were observed in this group, indicating unaffected photosynthetic efficiency. PS NP exposure triggered the antioxidant system in L. minor plants and resulted in a 3- and 4.6-fold increase in superoxide dismutase (SOD) activity in the P-1 and P-2 groups. On the other hand, high-dose PS NP treatment resulted in insufficient antioxidant activity in the P-2 group and increased hydrogen peroxide (H2O2) and lipid peroxidation (TBARS contents) by 25 % and 17 % compared to the control plants. Furthermore, PS NP exposure triggered abscisic acid biosynthesis (two-fold in the P-1 and three-fold in the P-2 group), which is also involved in regulating the stress response. In conclusion, L. minor plants tolerated NP accumulation without growth suppression, oxidative stress damage and limitations in photosynthetic capacity and have the potential to be used in remediation studies of NP-contaminated waters.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 Multiwalled Carbon Nanotubes Alter the PSII Photochemistry, Photosystem-Related Gene Expressions, and Chloroplastic Antioxidant System in Zea mays under Copper Toxicity(Amer Chemical Soc, 2022) Alp, Fatma Nur; Arikan, Busra; Ozfidan-Konakci, Ceyda; Balci, Melike; Yildiztugay, Evren; Cavusoglu, HalitA critical approach against copper (Cu) toxicity is the use of carbon nanomaterials (CNMs). However, the effect of CNMs on Cu toxicity-exposed chloroplasts is not clear. The photosynthetic, genetic, and biochemical effects of multiwalled carbon nanotubes (50-100-250 mg L-1 CNT) were investigated under Cu stress (50-100 mu M CuSO4) in Zea mays chloroplasts. F-v/F-m and F-v/F-o were suppressed under stress. Stress altered the antioxidant system and the expression of psaA, psaB, psbA, and psbD. The chloroplastic activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione S-transferase (GST), and glutathione peroxidase (GPX) increased under CNT + stress, and those of hydrogen peroxide (H2O2) and lipid peroxidation decreased. CNTs were promoted to the maintenance of the redox state by regulating enzyme/non-enzyme activity/contents involved in the AsA-GSH cycle. Furthermore, CNTs inverted the negative effects of Cu by upregulating the transcriptions of photosystem-related genes. However, the high CNT concentration had adverse effects on the antioxidant capacity. CNT has great potential to confer tolerance by reducing Cu-induced damage and protecting the biochemical reactions of photosynthesis.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 Polyamine Cadaverine Detoxifies Nitrate Toxicity on the Chloroplasts of Triticum aestivum Through Improved Gas Exchange, Chlorophyll a Fluorescence and Antioxidant Capacity(Springer, 2023) Balci, Melike; Alp, Fatma Nur; Arikan, Busra; Ozfidan-Konakci, Ceyda; Yildiztugay, EvrenNitrate (NO3-) toxicity is a serious problem that threatens the health of living organisms and especially agricultural production. The presence of NO3- leads to biomass loss by causing the imbalance of biochemical metabolism and inhibiting photosynthetic activity. A new critical approach to cope with nitrate toxicity is the use of polyamines (PAs) as an antioxidant defence system enhancer in plants. However, there is no information about the impacts of cadaverine, is one of PAs, on chloroplasts of plants exposed to NO3- toxicity. For this purpose, this study focused on the photosynthetic and biochemical process taking place in chloroplasts of Triticum aestivum under nitrate stress (100 mM and 200 mM NO3-) and/or cadaverine (100 mu M and 1 mM Cad). Gas exchange, chlorophyll fluorescence (F-v/F-m and F-v/F-o), the efficiency of the light reaction (phi P-o/(1 - phi P-o)), the performance index (PItotal), and relative water content (RWC) levels were suppressed under NO3- stress. Stress did not improve the antioxidant activities in chloroplasts such as superoxide dismutase (SOD), glutathione reductase (GR). After 100 mM NO3- exposure, Cad increased chloroplastic SOD, peroxidase (POX), ascorbate peroxidase (APX), GR, monodehydroascorbate reductase (MDHAR), and glutathione S-transferase (GST) activities. In the presence of 200 mM NO3-, Cads decreased SOD and GST activity. In NO3- + Cad-applied wheat, the high contents of hydrogen peroxide (H2O2) and lipid peroxidation (TBARS) were effectively removed through ascorbate (AsA) regeneration. Cads promoted the maintenance of cellular redox state by regulating antioxidant pathways included in the ascorbate-glutathione (AsA-GSH) cycle. Our results showed that Cad has great potential to confer tolerance to wheat by reducing oxidative damage and protecting the biochemical reactions of photosynthesis against NO3- toxicity.Öğe Polyamine, 1,3-diaminopropane, regulates defence responses on growth, gas exchange, PSII photochemistry and antioxidant system in wheat under arsenic toxicity(Elsevier France-Editions Scientifiques Medicales Elsevier, 2023) Gulenturk, Cagri; Alp-Turgut, Fatma Nur; Arikan, Busra; Tofan, Aysenur; Ozfidan-Konakci, Ceyda; Yildiztugay, EvrenThe metalloid arsenic (As) is extremely hazardous to all living organisms, including plants. Pollution with As is very detrimental to the photosynthetic machinery, cell division, energy generation, and redox status. In order to cope with stress, the use of growth regulators such as polyamines (PA), which strengthen the antioxidant system of plants, has become widespread in recent years. PAs can modulate the plant growth through basic mechanisms common to all living organisms, such as membrane stabilization, free radical scavenging, deoxyribonucleic acid (DNA), ribonucleic acid (RNA) and protein synthesis, enzyme activities and second messengers. However, the effect of 1,3-diaminopropane (Dap), which is a product of PA catabolism, is not clear enough in plants exposed to As toxicity. In the current study, the different concentrations of 1,3-diaminopropane (0.1, 0.5 and 1 mM Dap) were hydroponically treated to wheat (Triticum aestivum) under arsenic stress (100 & mu;M As) and then relative growth rate (RGR), relative water content (RWC), proline content (Pro), gas exchange parameters, PSII photo-chemistry, chlorophyll fluorescence kinetics, antioxidant activity and lipid peroxidation were assessed. RGR, RWC, osmotic potential and Pro content decreased in As-applied plants. The inhibition of these parameters could be reversed by Dap treatments. Besides, Dap applications mitigated the As toxicity-induced suppression on chlorophyll fluorescence (Fv/Fm, Fv/Fo and Fo/Fm) and the performance of PSII photochemistry. As impaired the balance on antioxidant capacity by decreased activities of catalase (CAT), peroxidase (POX), glutathione peroxidase (GPX), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and the contents of ascorbate (AsA) and glutathione (GSH) and then lipid peroxidation (TBARS content) increased. In the presence of Dap under As stress, the plants exhibited an increase in superoxide dismutase (SOD), POX, and GPX. Dap treatments contributed to the maintenance of cellular redox state (AsA/ DHA and GSH/GSSG) by regulating the activities/contents of enzyme/non-enzyme involved in the AsA-GSH cycle. After Dap applications against stress, ROS accumulation (H2O2 content) and lipid peroxidation (TBARS) were effectively reduced. The findings showed that by eliminating As-induced oxidative damage and protecting the biochemical processes of photosynthesis, Dap treatments have a substantial potential to give resistance to wheat.Öğe Polystyrene nanoplastic contamination mixed with polycyclic aromatic hydrocarbons: Alleviation on gas exchange, water management, chlorophyll fluorescence and antioxidant capacity in wheat(Elsevier Sci Ltd, 2022) Arikan, Busra; Ozfidan-Konakci, Ceyda; Yildiztugay, Evren; Turan, Metin; Cavusoglu, HalitPolycyclic aromatic hydrocarbons (PAHs) constitute a significant environmental pollution group that reaches toxic levels with anthropogenic activities. The adverse effects of nanoplastics accumulating in ecosystems with the degradation of plastic wastes are also a growing concern. Previous studies have generally focused on the impact of single PAH or plastic fragments exposure on plants. However, it is well recognized that these contaminants co-exist at varying rates in agricultural soil and water resources. Therefore, it is critical to elucidate the phytotoxicity and interaction mechanisms of mixed pollutants. The current study was designed to comparatively investigate the single and combined effects of anthracene (ANT, 100 mg L-1), fluorene (FLU, 100 mg L-1) and polystyrene nanoplastics (PS, 100 mg L-1) contaminations in wheat. Plants exposed to single ANT, FLU and PS treatments demonstrated decline in growth, water content, high stomatal limitations and oxidative damage. The effect of ANT + FLU on these parameters was more detrimental. In addition, ANT and/or FLU treatments significantly suppressed photosynthetic capacity as determined by carbon assimilation rate (A) and chlorophyll a fluorescence transient. The antioxidant system was not fully activated (decreased superoxide dismutase, peroxidase and glutathione reductase) under ANT + FLU, then hydrogen peroxide (H2O2) content (by 2.7-fold) and thiobarbituric acid reactive substances (TBARS) (by 2.8-fold) increased. Interestingly, ANT + PS and FLU + PS improved the growth, water relations and gas exchange parameters. The presence of nanoplastics recovered the adverse effects of ANT and FLU on growth by protecting the photosynthetic photochemistry and reducing oxidative stress. PAH plus PS reduced the ANT and FLU accumulation in wheat leaves. In parallel, the increased antioxidant system, regeneration of ascorbate, glutathione and glutathione redox status observed under ANT + PS and FLU + PS. These findings will provide an information about the phytotoxicity mechanisms of mixed pollutants in the environment.
