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Öğe Hormetic activation of nano-sized rare earth element terbium on growth, PSII photochemistry, antioxidant status and phytohormone regulation in Lemna minor(Elsevier, 2023) Alp, Fatma Nur; Arıkan, Büşra; Özfidan Konakçı, Ceyda; Gülentürk, Çağrı; Yıldıztugay, Evren; Turan, Metin; Çavuşoğlu, HalitSoils contaminated with rare earth elements (REEs) can damage agriculture by causing physiological disorders in plants which are evaluated as the main connection of the human food chain. A biphasic dose response with excitatory responses to low concentrations and inhibitory/harmful responses to high concentrations has been defined as hormesis. However, not much is clear about the ecological effects and potential risks of REEs to plants. For this purpose, here we showed the impacts of different concentrations of nano terbium (Tb) applications (510-25-50-100-250-500 mg L-1) on the accumulation of endogeneous certain ions and hormones, chlorophyll fluoresence, photochemical reaction capacity and antioxidant activity in duckweed (Lemna minor). Tb concentrations less than 100 mg L (-1) increased the contents of nitrogen (N), phosphate (P), potassium (K+), calcium (Ca2+), magnesium (Mg2+), manganese (Mn2+) and iron (Fe2+). Chlorophyll fluorescence (Fv/Fm and Fv/Fo) was suppressed under 250-500 mg L-1 Tb. In addition, Tb toxicity affected the trapped energy adversely by the active reaction center of photosystem II (PSII) and led to accumulation of inactive reaction centers, thus lowering the detected level of electron transport from photosystem II (PSII) to photosystem I (PSI). On the other hand, 5-100 mg L-1 Tb enhanced the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), NADPH oxidase (NOX), ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and glutathione S-transferase (GST). Tb (5-50 mg L-1) supported the maintenance of cellular redox status by promoting antioxidant pathways involved in the ascorbateglutathione (AsA-GSH) cycle. In addition to the antioxidant system, the contents of some hormones such as indole-3-acetic acid (IAA), gibberellic acid (GA), cytokinin (CK) and salicylic acid (SA) were also induced in the presence of 5-100 mg L-1 Tb. In addition, the levels of hydrogen peroxide (H2O2) and lipid peroxidation (TBARS) were controlled through ascorbate (AsA) regeneration and effective hormonal modulation in L. minor. However, this induction in the antioxidant system and phytohormone contents could not be resumed after applications higher than 250 mg L-1 Tb. TBARS and H2O2, which indicate the level of lipid peroxidation, increased. The results in this study showed that Tb at appropriate concentrations has great potential to confer tolerance of duckweed by supporting the antioxidant system, protecting the biochemical reactions of photosystems and improving hormonal regulation.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 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.Öğe Rare earth element scandium mitigates the chromium toxicity in Lemna minor by regulating photosynthetic performance, hormonal balance and antioxidant machinery(Elsevier, 2023) Alp, Fatma Nur; Arıkan, Büşra; Özfidan Konakçı, Ceyda; Ekim, Rumeysa; Yıldıztugay, Evren; Turan, MetinChromium (Cr) toxicity is a serious problem that threatens the health of living organisms and especially agricultural production. The presence of excess Cr leads to biomass loss by causing the imbalance of biochemical metabolism and inhibiting photosynthetic activity. A new critical approach to cope with Cr toxicity is the use of the rare earth elements (REEs) as an antioxidant defence system enhancer in plants. However, the effect of scandium (Sc), which is one of the REEs, is not clear enough in Lemna minor exposed to Cr toxicity. For this purpose, the photosynthetic and biochemical effects of scandium (50 μM and 200 μM Sc) treatments were investigated in Lemna minor under Cr stress (100 μM, 200 μM and 500 μM Cr). Parameters related to photosynthesis (Fv/Fm, Fv/Fo) were suppressed under Cr stress. Stress altered antioxidant enzymes activities and hormone contents. Sc applications against stress increased the activities of superoxide dismutase (SOD), NADPH oxidase (NOX), ascorbate peroxidase (APX), lutathione reductase (GR), monodehydroascorbate reductase (MDHAR), and glutathione S-transferase (GST). In addition to the antioxidant system, the contents of indole-3- acetic acid (IAA), abscisic acid (ABA) and jasmonic acid (JA) were also rearranged. However, in all treatment groups, with the provision of ascorbate (AsA) regeneration and effective hormone signaling, reactive oxygen species (ROS) retention which result in high hydrogen peroxide (H2O2) content and lipid peroxidation (TBARS) were effectively removed. Sc promoted the maintenance of cellular redox state by regulating antioxidant pathways included in the AsA-GSH cycle. Our results showed that Sc has great potential to confer tolerance to duckweed by reducing Cr induced oxidative damage, protecting the biochemical reactions of photosynthesis, and improving hormone signaling.Öğe Responses of individual and combined polystyrene and polymethyl methacrylate nanoplastics on hormonal content, fluorescence/photochemistry of chlorophylls and ROS scavenging capacity in Lemna minor under arsenic-induced oxidative stress(Elsevier, 2023) Özfidan Konakçı, Ceyda; Yıldıztugay, Evren; Arıkan, Büşra; Alp Turgut, Fatma Nur; Turan, Metin; Çavuşoğlu, Halit; Şakalak, HüseyinNanoplastics alter the adverse impacts of hazardous contaminants such as heavy metals by changing their adsorption and accumulation. Few findings are available on the interaction between nanoplastic and heavy metals in plants. However, there is no report on the mechanisms for removing metal stress-mediated oxidative damage by the combination treatments of nanoplastics. To address this lack of information, polystyrene nano-plastic (PS, 100 mg L-1) and polymethyl methacrylate (PMMA, 100 mg L-1) were hydroponically applied to Lemna minor exposed to arsenate (As, 100 mu M) for 7 days. PS or PMMA caused a reduction in the contents of N, P, K, Ca, Mg and Mn, but the improved contents were detected in the presence of PS or PMMA plus As stress. The hormone contents (auxin, gibberellic acid, cytokinin, salicylic acid and jasmonic acid) reduced by stress were re-arranged through PS or PMMA applications. Based on chlorophyll efficiency, fluorescence kinetics and performance of PSII, the impaired photosynthesis by As stress was improved via PS or PMMA applications. This alleviation did not continue under the combined form of PS and PMMA in As-applied plants. All analyzed antioxidant activity (superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione S-transferase (GST), glutathione peroxidase (GPX), monodehydroascorbate reduc-tase (MDHAR) and dehydroascorbate reductase (DHAR)) decreased or unchanged under As, PS or PMMA. Due to the inactivation of the defense system, L. minor had high levels of hydrogen peroxide (H2O2) and thiobarbituric acid reactive substances (TBARS), showing lipid peroxidation. After As toxicity, induvial applications of PS or PMMA indicated the activated enzyme capacity (SOD, POX, GST and GPX) and upregulated AsA/DHA, GSH/ GSSG and redox state of GSH, which facilitated the removal of radical accumulation. The efficiency of the antioxidant system in As + PS + PMMA-applied L. minor was not enough to remove damage induced by As stress; hereby, TBARS and H2O2 contents were similar to the As-treated group. Our findings from alone or combined application of PS and PMMA provide new information to advance the tolerance mechanism against As exposure in L. minor.Öğe Seydişehir alüminyum çalışanlarında alkol kullanımı ve bağımlılığının demografik, ruhsal, toplumsal özellikleri(Necmettin Erbakan Üniversitesi Meram Tıp Fakültesi, 1999) Turan, Metin; Aşkın, RüstemBu çalışma 1997 yılında Konya-Seydişehir Alüminyum İşletme müdürlüğü bünyesinde çalışan ve rastgele örneklemle seçilen 1670 denek üzerinde gerçekleştirildi. Alkol bağımlılığı epidemiyolojik, demografik, sosyal ve ruhsal belirtiler açısından araştırıldı. Çalışmada veri toplamak için kişisel bilgi formu, alkol kullanım formu, Michigan Alkol Tarama Testi (MATT), CAGE testi, Belirti Tarama Listesi (SCL-90-R) kullanıldı. Veriler istatistiksel olarak SPSS programında ki kare, tek yönlü varyans analizi (ANOVA), lojistik regresyon analizi ile değerlendirildi. Çalışmada deneklerin % 26. Tinin (436 kişi) alkol kullandığı, MATT puanlarına göre % 5.47' ünün (91 kişi) alkolü bağımlılık düzeyinde kullandığı saptandı. Ayrıca çalışılan grubun % 8.4'ünün (140 kişi) alkol kötüye kullanıcısı, %12.3'ünün (206 kişi) sorunsuz içici olduğu belirlendi. Bağımlılık düzeyinde alkol kullanmanın işçiler arasında(p=0.0001), eğitim(p=0. 00001) ve gelir düzey leri(p=0. 03) düşük kişilerde daha sık olduğu bulundu; bu kişilerin ortalama 20'li yaşlarda alkole başladıkları, 15 yıllık bir alkol kullanım öyküsü olduğu ve ortalama 3.38 standart alkol miktarı tükettikleri bulundu. Cinsiyetin erkek oluşu, çocukluk ve ergenlik döneminde aile içi çatışmaların varlığı, eğitim ve ekonomik düzeyin düşük oluşu, ailede alkol kullanan kişilerin bulunması, tüketilen alkolün miktarının fazla oluşunun bağımlılık için yatkınlaştırıcı etkenler olduğu saptandı (p=0.0003). Alkol bağımlılarında kişisel, ailevi, mesleki ve toplumsal sorunların daha yoğun olduğu(p=0. 00001), alkol nedeni ile trafik suçu(p=0. 00002) ve diğer suçlara(p=0.0005) daha fazla karıştığı tespit edildi. Depresyon ve anksiyete başta olmak üzere fobik anksiyete, öfke, paranoid, 54düşünce psikotik, kişiler arası duyarlılık belirtilerinin alkol bağımlılarında diğer içicilerden ve alkol kullanmayanlardan daha fazla olduğu bulundu (p=0.0001).
