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1.
Pestic Biochem Physiol ; 158: 135-142, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31378349

RESUMO

Triflumizole is one of imidazole fungicides that works by inhibiting ergosterol biosynthesis, and is widely used for the control of powdery mildew and scabs on various fruits and crops. Triflumizole residue has been frequently detected in soil and aquatic ecosystems. While many studies have focused on its toxic effect on terrestrial and aquatic animals, little attention has been paid to aquatic algae, the primary producers of aquatic environments. Therefore, we evaluated the acute (96 h) toxicity effects of triflumizole on the freshwater algae Chlorella vulgaris, by examining growth, cell morphology, photosynthesis, and oxidative stress. The results showed that the 96 h median inhibition concentration (96 h-EC50) was 0.82 mg/L (95% confidential interval 0.70-0.98 mg/L).The growth of algal cells was conspicuously inhibited by triflumizole exposure, and the cell surfaces appeared to be shrunkThe chlorophyll content (including Chl-a, Chl-b and T-Chl) dramatically decreased at triflumizole concentrations of 0.2 and 1.0 mg/L. In addition, the transcript abundance of photosynthesis-related genes (psaB, psbC and rbcL) showed obvious decreases in above treatments after 96 h of exposure to triflumizole. Moreover, the algal growth inhibition was accompanied by an increase in intracellular reactive oxygen species and malondialdehyde content, as well as increased activity of antioxidant enzymes such as superoxide dismutase and peroxidase, indicating oxidative stress and lipid peroxidation. Our findings reveal that triflumizole has potential toxicity to the primary producers (freshwater algae) in aquatic ecosystems.


Assuntos
Chlorella vulgaris/efeitos dos fármacos , Imidazóis/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Peroxidase/metabolismo , Fotossíntese/efeitos dos fármacos , Superóxido Dismutase/metabolismo
2.
J Environ Sci (China) ; 84: 42-50, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31284915

RESUMO

Ethylenediurea (EDU) has been used as a chemical protectant against ozone (O3). However, its protective effect and physiological mechanisms are still uncertain. The present study aimed to investigate the changes of foliar visible injury, physiological characteristics and emission rates of volatile organic compounds (VOCs) in one-year-old Populus alba "Berolinensis" saplings pretreated with EDU and exposed to elevated O3 (EO, 120 µg/m3). The results showed that foliar visible injury symptoms under EO were significantly alleviated in plants with EDU application (p < 0.05). Under EO, net photosynthetic rate, the maximum photochemical efficiency of PSII and the photochemical efficiency of PSII of plants pretreated with 300 and 600 mg/L EDU were similar to unexposed controls and significantly higher compared to EO-stressed plants without EDU pretreatment, respectively. Malondialdehyde content was highest in EO without EDU and decreased significantly by 14.9% and 21.3% with 300 and 600 mg/L EDU pretreatment, respectively. EDU pretreatment alone increased superoxide dismutase activity by 10-fold in unexposed plants with further increases of 88.4% and 37.5% in EO plants pretreated with 300 and 600 mg/L EDU pretreatment, respectively (p < 0.05). Abscisic acid content declined under EO relative to unexposed controls with the effect partially reversed by EDU pretreatments. Similarly, VOCs emission rate declined under EO relative to unexposed plants with a recovery of emission rate observed with 300 and 600 mg/L EDU pretreatment. These findings provided significant evidence that EDU exerted a beneficial effect and protection on the tested plants against O3 stress.


Assuntos
Ozônio/toxicidade , Compostos de Fenilureia/farmacologia , Fotossíntese/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Populus/efeitos dos fármacos , Populus/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Compostos Orgânicos Voláteis/metabolismo
3.
Chemosphere ; 233: 954-965, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31340423

RESUMO

Heavy metals such as cadmium and zinc constitute major pollutants in coastal areas and frequently accumulate in salt marshes. The wetland halophyte plant species Kosteletzkya pentacarpos is a promising species for phytostabilization of contaminated areas. In order to assess the role of the antisenescing phytohormone cytokinin in heavy metal resistance in this species, seedlings were exposed for two weeks to Cd (10 µM), Zn (100 µM) or Cd + Zn (10 µM + 100 µM) in the presence or absence of 50 mM NaCl and half of the plants were sprayed every two days with the cytokinin trans-zeatine riboside (10 µM). Zinc reduced the endogenous cytokinin concentration. Exogenous cytokinin increased plant growth, stomatal conductance, net photosynthesis and total ascorbate and reduced oxidative stress estimated by malondialdehyde in Zn-treated plants maintained in the absence of NaCl. Heavy metal induced an increase in the senescing hormone ethylene which was reduced by cytokinin treatment. Plants exposed to the mixed treatment (Cd + Zn) exhibited a specific hormonal status in relation to accumulation of abscisic acid and depletion of salicylic acid. Non-protein thiols (glutathione and phytochelatins) accumulated in response to Cd and Cd + Zn. It is concluded that toxic doses of Cd and Zn have different impacts on the plant behavior and that the simultaneous presence of the two elements induces a specific physiological constraint at the plant level. Salinity helps the plant to cope with heavy metal toxicities and the plant hormone cytokinin assumes key function in Zn resistance but its efficiency is lower in the presence of NaCl.


Assuntos
Cádmio/toxicidade , Citocininas/metabolismo , Hibiscus/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Cloreto de Sódio/farmacologia , Zinco/toxicidade , Ácido Abscísico/análise , Glutationa/metabolismo , Hibiscus/crescimento & desenvolvimento , Fotossíntese/efeitos dos fármacos , Fitoquelatinas/metabolismo , Desenvolvimento Vegetal/efeitos dos fármacos , Ácido Salicílico/análise , Salinidade , Plântula/fisiologia , Poluentes Químicos da Água/toxicidade , Áreas Alagadas
4.
Environ Sci Pollut Res Int ; 26(23): 23571-23582, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31203541

RESUMO

This study investigates the impact of humic acid (HA) on the toxicity of selected herbicides and their binary mixtures to aquatic plants. The focus was on two auxin simulators (2,4-D and dicamba) and two photosynthetic inhibitors (atrazine and isoproturon). The results suggested that the addition of HA to the standard synthetic medium does not affect Lemna minor growth nor the toxicity of atrazine, but increases the toxicity of 2,4-D and the binary mixture of atrazine and 2,4-D. The addition of HA to the standard synthetic medium reversibly decreased the growth (biomass) of Myriophyllum aquaticum and enhanced the toxicity of individually tested herbicides (isoproturon and dicamba) as well as their binary mixture. The results showed delayed toxic effects of auxin simulators, especially 2,4-D in the Lemna test. The recovery after the exposure to individual photosystem II inhibitors (atrazine and isoproturon) is fast in both plant species, regardless of the presence of HA. In the case of selected mixtures (atrazine + 2,4-D and isoproturon + dicamba), recovery of both plant species was noted, while the efficiency depended on the herbicide concentration in the mixture rather than the presence or absence of HA.


Assuntos
Herbicidas/toxicidade , Substâncias Húmicas/análise , Plantas/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Araceae/efeitos dos fármacos , Atrazina/toxicidade , Dicamba , Compostos de Fenilureia , Fotossíntese/efeitos dos fármacos
5.
Aquat Toxicol ; 212: 247-258, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31170659

RESUMO

The objective of this study was to investigate the combined effects of varying dissolved CO2 concentration (ambient CO2, 3˜17 µmol L-1, elevated CO2, 48˜81 µmol L-1) and light intensity (high light, c. 150 µmol photon m-2 s-1, low light, c. 25 µmol photon m-2 s-1) on the bioaccumulation and phytotoxicity of cadmium (Cd) in a macrophyte Potamogeton crispus, under constant Cd exposure. The data confirmed that 100 µM Cd led to adverse changes in morphology, ultrastructure and biochemistry in P. crispus. The toxic effects depended strongly on CO2 concentration and light intensity: elevated CO2 and high light both increased Cd concentrations in P. crispus, and there was a significant interaction between the two factors. Compared to high light grown plants, the photochemical efficiency and chlorophyll content of low light grown P. crispus were much less affected and the MDA content was lower, when exposed to 100 µM Cd. In addition, an antioxidative response was observed with a significant increase in SOD, POD and GST activities, indicating that low light grown P. crispus are more protected against Cd toxicity. When compared with ambient CO2 concentrations, chlorophyll content, chlorophyll fluorescence, photosynthetic rate and starch content, as well as the activity of SOD and GST, were significantly enhanced in Cd treated P. crispus under elevated CO2. This suggests that elevated CO2 reduced Cd toxicity in P. crispus by increasing photosynthesis and enhancing the antioxidant system. Moreover, the statistical results showed that dissolved CO2 and light had additive effects on Cd toxicity in P. crispus, reflected by the physiological parameters of total chlorophyll content, SOD activity and MDA content, indicating that the combination of high CO2 and low light produced more protection against Cd toxicity than did the factors alone. Based on the results of this study, it appears clear that referring to a specific site in aquatic ecosystem, dissolved CO2 concentration and light availability should be considered when assessing and managing Cd impacts on aquatic plants.


Assuntos
Cádmio/toxicidade , Dióxido de Carbono/metabolismo , Meio Ambiente , Luz , Potamogetonaceae/efeitos dos fármacos , Potamogetonaceae/efeitos da radiação , Antioxidantes/farmacologia , Clorofila/metabolismo , Fotossíntese/efeitos dos fármacos , Fotossíntese/efeitos da radiação , Poluentes Químicos da Água/toxicidade
6.
Environ Pollut ; 251: 961-969, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31234263

RESUMO

Phycoremediation technologies significantly contribute to solving serious problems induced by heavy metals accumulation in the aquatic systems. Here we studied the mechanisms underlying Al stress tolerance in two diazotrophic cyanobacterial species, to identify suitable species for Al phycoremediation. Al uptake as well as the physiological and biochemical responses of Anabaena laxa and Nostoc muscorum to 7 days Al exposure at two different concentrations i.e., mild (100 µM) and high dose (200 µM), were investigated. Our results revealed that A. laxa accumulated more Al, and it could acclimatize to long-term exposure of Al stress. Al induced a dose-dependent decrease in photosynthesis and its related parameters e.g., chlorophyll content (Chl a), phosphoenolpyruvate carboxylase (PEPC) and Ribulose‒1,5‒bisphosphate carboxylase/oxygenase (RuBisCo) activities. The affect was less pronounced in A. laxa than N. muscorum. Moreover, Al stress significantly increased cellular membrane damage as indicated by induced H2O2, lipid peroxidation, protein oxidation, and NADPH oxidase activity. However, these increases were lower in A. laxa compared to N. muscorum. To mitigate the impact of Al stress, A. laxa induced its antioxidant defense system by increasing polyphenols, flavonoids, tocopherols and glutathione levels as well as peroxidase (POX), catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GPX) enzymes activities. On the other hand, the antioxidant increases in N. muscorum were only limited to ascorbate (ASC) cycle. Overall, high biosorption/uptake capacity and efficient antioxidant defense system of A. laxa recommend its feasibility in the treatment of Al contaminated waters/soils.


Assuntos
Alumínio/metabolismo , Anabaena/metabolismo , Antioxidantes/metabolismo , Biodegradação Ambiental , Nostoc muscorum/metabolismo , Fotossíntese/efeitos dos fármacos , Ácido Ascórbico/metabolismo , Catalase/metabolismo , Clorofila/metabolismo , Glutationa/metabolismo , Glutationa Redutase/metabolismo , Peroxidação de Lipídeos , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Peroxidases/metabolismo , Fosfoenolpiruvato Carboxilase/metabolismo , Ribulose-Bifosfato Carboxilase/metabolismo
7.
Plant Sci ; 285: 239-247, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31203889

RESUMO

Foxtail millet (Setaria italica) is a nutrient-rich food source traditionally grown in arid and semi-arid areas, as it is well adapted to drought climate. Yet there is limited information as how the crop responses to the changing climate. In order to investigate the response of foxtail millet to elevated [CO2] and the underlying mechanism, the crop was grown at ambient [CO2] (400 µmol mol-1) and elevated [CO2] (600 µmol mol-1) in an open-top chamber (OTC) experimental facility in North China. The changes in leaf photosynthesis, chlorophyll fluorescence, biomass, yield and global gene expression in response to elevated [CO2] were determined. Despite foxtail millet being a C4 photosynthetic crop, photosynthetic rates (PN) and intrinsic water-use efficiency (WUEi), were increased under elevated [CO2]. Similarly, grain yield and above-ground biomass also significantly increased (P <  0.05) for the two years of experimentation under elevated [CO2]. Increases in seeds and tiller number, spike and stem weight were the main contributors to the increased grain yield and biomass. Using transcriptomic analyses, this study further identified some genes which play a role in cell wall reinforcement, shoot initiation, stomatal conductance, carbon fixation, glycolysis / gluconeogenesis responsive to elevated [CO2]. Changes in these genes reduced plant height, increased stem diameters, and promote CO2 fixation. Higher photosynthetic rates at elevated [CO2] demonstrated that foxtail millet was not photosynthetically saturated at elevated [CO2] and its photosynthesis response to elevated [CO2] were analogous to C3 plants.


Assuntos
Fotossíntese/efeitos dos fármacos , Setaria (Planta)/efeitos dos fármacos , Biomassa , Dióxido de Carbono/metabolismo , Clorofila/metabolismo , Produção Agrícola , Sequenciamento de Nucleotídeos em Larga Escala , Reação em Cadeia da Polimerase em Tempo Real , Setaria (Planta)/genética , Setaria (Planta)/crescimento & desenvolvimento , Setaria (Planta)/metabolismo , Transcriptoma/efeitos dos fármacos
8.
Mar Pollut Bull ; 144: 173-180, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31179985

RESUMO

We investigated how elevated CO2 affects the responses of Gracilariopsis lemaneiformis and Ulva lactuca to NH4+ enrichments. All algae were incubated under four nutritional conditions (zero addition, 100, 500, and 2500 µM NH4+), and two CO2 levels (390 ppm and 1000 ppm). The growth, photosynthesis, and soluble protein contents of both species increased under the eutrophication condition (100 µM NH4+). However, the growth and carotenoid contents of the two species declined when NH4+ concentration increased. Under the super eutrophication condition (2500 µM NH4+), all indexes measured in G. lemaneiformis were suppressed, while the growth and photosynthesis in U. lactuca changed indistinctively, both compared with the control. Moreover, under the super eutrophication condition, elevated CO2 reduced the suppression in the growth of G. lemaneiformis, but decreased the growth of U. lactuca. Nonetheless, G. lemaneiformis displayed much lower growth rates than U. lactuca under the super eutrophication and elevated CO2 condition.


Assuntos
Compostos de Amônio/toxicidade , Dióxido de Carbono/toxicidade , Fotossíntese/efeitos dos fármacos , Rodófitas/crescimento & desenvolvimento , Ulva/crescimento & desenvolvimento , Poluentes Químicos da Água/toxicidade , Compostos de Amônio/metabolismo , Antioxidantes/metabolismo , Dióxido de Carbono/metabolismo , Eutrofização , Modelos Teóricos , Rodófitas/metabolismo , Água do Mar/química , Ulva/metabolismo
9.
Plant Physiol Biochem ; 141: 154-163, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31163342

RESUMO

Different nitrogen (N) sources have been reported to significantly affect the photosynthesis (Pn) and its attributes. However, molybdenum (Mo) induced effects on photosynthetic efficacy of winter wheat under different N sources have not been investigated. A hydroponic study was carried out comprising of two winter wheat cultivars '97003' and '97014' as Mo-efficient and Mo-inefficient, respectively to underpin the effects of Mo supply (0 and 1 µM) on photosynthetic efficacy of winter wheat under different N sources (NO3̶, NH4NO3 or NH4+). The results revealed that Mo-induced increases in dry weight, gas exchange parameters, chlorophyll contents, NR activities, NO3̶ assimilation, total N contents and transcripts of TaNR and TaNRT1.1 genes under different N sources followed the trend of NH4NO3 > NO3̶ > NH4+, suggesting that Mo has more complementary effects to nitrate nutrition than sole ammonium. Interestingly, under Mo-deprivation environments, cultivar '97003' recorded more pronounced alterations in Mo-dependent parameters than '97014' cultivar. Moreover, Mo application significantly improved the chlorophyll contents and chloroplast configuration in all N sources showing that Mo has a key role in chlorophyll biosynthesis and chloroplast integrity. The results also highlighted that Mo-induced enhancements in total N contents and photosynthetic characteristics followed the same order as NH4NO3 > NO3- > NH4+, suggesting that Mo might affect Pn through N metabolism. In crux, our study findings imply that Mo supply increased Pn not only through chlorophyll synthesis and chloroplast configuration but also by N uptake and assimilation which may represent a strategy of Mo fertilizer to strengthen the photosynthetic machinery.


Assuntos
Compostos de Amônio/metabolismo , Molibdênio/farmacologia , Nitrogênio/metabolismo , Fotossíntese/efeitos dos fármacos , Triticum/fisiologia , Clorofila/metabolismo , Cloroplastos/metabolismo , Fertilizantes , Hidroponia , Microscopia Eletrônica de Transmissão , Nitratos/metabolismo , Proteínas de Plantas/metabolismo , Triticum/efeitos dos fármacos
10.
Ecotoxicol Environ Saf ; 181: 146-154, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31177079

RESUMO

The impact of lead (Pb) on Spirodela polyrhiza was studied to determine the subcellular distribution, chemical forms, and resulting morphophysiological modifications after treatments with 20 or 80 µM Pb(NO3)2 for 10 days. At the subcellular level, the Pb uptake by S. polyrhiza was mainly compartmentalized in the cell walls (70%), and the majority of Pb (approximately 70%) was extracted using 1 M NaCl and 2% acetic acid (HAc). Visual symptoms of phytotoxcity, surface roughness and closure of stomata, were observed in Pb-treated fronds. Electron-dense precipitates were present in cell walls, and changes to the ultrastructure were most noticeably exhibited in organelle shape, internal organization, and size of the plastoglobules of chloroplasts. Toxic concentrations of Pb induced oxidative stress in fronds, characterized by an accumulation of malondialdehyde (MDA) and decreased chlorophyll and unsaturated fatty acid contents. Pb exposure increased ABS/RC, TRo/RC, DIo/RC, Vj, and φDo (Fv/Fm), indicating that reaction centers were transformed to dissipation sinks, leading to a decrease in the efficiency of photosystem II, which was evident from the decreased values of Fv/Fo, Fv/Fm, ψEo, φEo, RC/ABS, and PIabs. These results indicated that decreased photosynthesis in Pb-treated fronds was partially ascribed to the lower pigment content, inhibition of electron transport, inactivation of the reaction centers, damage to the chloroplast ultrastructure, and stomatal closure. The physiological implications of subcellular distribution and chemical forms are discussed in relation to Pb accumulation and detoxification. However, Pb accumulation significantly impaired photosynthesis and membrane integrity in the fronds of S. polyrhiza.


Assuntos
Araceae/efeitos dos fármacos , Chumbo/toxicidade , Araceae/anatomia & histologia , Araceae/metabolismo , Araceae/ultraestrutura , Clorofila/metabolismo , Cloroplastos/efeitos dos fármacos , Cloroplastos/ultraestrutura , Transporte de Elétrons/efeitos dos fármacos , Ácidos Graxos Insaturados/metabolismo , Chumbo/farmacocinética , Malondialdeído/metabolismo , Fotossíntese/efeitos dos fármacos , Complexo de Proteína do Fotossistema II/metabolismo
11.
BMC Plant Biol ; 19(1): 253, 2019 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-31196035

RESUMO

BACKGROUND: Because of their broad applications in our life, nanoparticles are expected to be present in the environment raising many concerns about their possible adverse effects on the ecosystem of plants. The aim of this study was to examine the effect of different sizes and concentrations of iron oxide nanoparticles [(Fe3O4) NPs] on morphological, physiological, biochemical, and ultrastructural parameters in tobacco (Nicotiana tabacum var.2 Turkish). RESULTS: Lengths of shoots and roots of 5 nm-treated plants were significantly decreased in all nanoparticle-treated plants compared to control plants or plants treated with any concentration of 10 or 20 nm nanoparticles. The photosynthetic rate and leaf area were drastically reduced in 5 nm (Fe3O4) NP-treated plants of all concentrations compared to control plants and plants treated with 10 or 20 nm (Fe3O4) NPs. Accumulation of sugars in leaves showed no significant differences between the control plants and plants treated with iron oxide of all sizes and concentrations. In contrast, protein accumulation in plants treated with 5 nm iron oxide dramatically increased compared to control plants. Moreover, light and transmission electron micrographs of roots and leaves revealed that roots and chloroplasts of 5 nm (Fe3O4) NPs-treated plants of all concentrations were drastically affected. CONCLUSIONS: The size and concentration of nanoparticles are key factors affecting plant growth and development. The results of this study demonstrated that the toxicity of (Fe3O4) NPs was clearly influenced by size and concentration. Further investigations are needed to elucidate more about NP toxicity in plants, especially at the molecular level.


Assuntos
Nanopartículas Metálicas , Tabaco/efeitos dos fármacos , Cloroplastos/efeitos dos fármacos , Cloroplastos/ultraestrutura , Relação Dose-Resposta a Droga , Compostos Férricos/farmacologia , Microscopia Eletrônica de Transmissão , Fotossíntese/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Folhas de Planta/ultraestrutura , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/ultraestrutura , Brotos de Planta/efeitos dos fármacos , Tabaco/metabolismo , Tabaco/ultraestrutura
12.
BMC Plant Biol ; 19(1): 258, 2019 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-31208344

RESUMO

BACKGROUND: It has been previously shown that oligo-carrageenan (OC) kappa increases growth, photosynthesis and activities of enzymes involved in basal and secondary metabolisms in Eucalyptus globulus. However, it is not known whether OC kappa may induce the activation of TOR pathway and the increase in expression of genes encoding proteins involved in photosynthesis and enzymes of basal and secondary metabolisms. RESULTS: E. globulus trees were sprayed on leaves with water (control) or with OC kappa 1 mg mL- 1, once a week, four times in total, and cultivated for 17 additional weeks (21 weeks in total). Treated trees showed a higher level of net photosynthesis than controls, beginning at week 3, a higher height, beginning at week 9, and those differences remained until week 21. In addition, treated trees showed an increase in the level of glucose beginning at week 1, trehalose at weeks 1-3, and in TOR-P level at week 1-2. On the other hand, transcripts encoding proteins involved in photosynthesis, and enzymes involved in glucose accumulation, C, N and S assimilation, and synthesis of secondary metabolites began at weeks 3-4 and with additional peaks at weeks 5-6, 8-11,13-14 and 17-19. Thus, OC kappa induced initial increases in glucose, trehalose and TOR-P levels that were followed by oscillatory increases in the level of transcripts coding for proteins involved in photosynthesis, and in basal and secondary metabolisms suggesting that initial increases in glucose, trehalose and TOR-P may trigger activation of gene expression. CONCLUSIONS: The stimulation of growth induced by OC kappa in E. globulus trees is due, at least in part, to activation of TOR pathway and the increase in expression of genes encoding proteins involved in photosynthesis and enzymes of basal metabolism.


Assuntos
Carragenina/farmacologia , Fotossíntese/efeitos dos fármacos , Metabolismo Basal/genética , Eucalyptus/genética , Eucalyptus/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Glucose/metabolismo , Fotossíntese/genética , Proteínas de Plantas/metabolismo , Metabolismo Secundário/efeitos dos fármacos , Metabolismo Secundário/genética , Serina-Treonina Quinases TOR/metabolismo , Trealose/metabolismo
13.
Plant Physiol Biochem ; 141: 315-324, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31207492

RESUMO

Different SA concentrations (10, 100 and 1000 µM) were applied in young olive trees (Olea europaea L.) subjected to drought and rewatering. Plants treated with 10 µM exhibited a close behavior to SA-starved plants. Although both 100 and 1000 µM improved the balance between ROS production and scavenging, 100 µM was more efficient. During drought, 100 µM improved ROS detoxification and scavenging by the maintenance or overaccumulation of soluble proteins. During recovery, soluble proteins return to well-watered values and increased the investment in non-enzymatic antioxidants. 100 µM was also the most effective in plant ionome regulation, improving macro and micronutrients uptake, namely P, Fe, Mn and Zn, and changing mineral allocation patterns. Therefore, 100 µM also countered the drought-induced decline in total plant biomass accumulation. The application of suitable SA concentrations is an efficient tool to improve cellular homeostasis and growth of plants subjected to recurrent drought episodes.


Assuntos
Secas , Íons/metabolismo , Olea/metabolismo , Oxirredução , Folhas de Planta/metabolismo , Ácido Salicílico/farmacologia , Antioxidantes/química , Biomassa , Minerais/química , Nutrientes/química , Estresse Oxidativo , Fotossíntese/efeitos dos fármacos , Raízes de Plantas/metabolismo , Portugal , Espécies Reativas de Oxigênio/metabolismo , Água/metabolismo
14.
Mar Pollut Bull ; 142: 155-163, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31232289

RESUMO

We aimed to show how the predicted pH decrease in the ocean would alter the toxicity, bioconcentration and dietary transfer of trace metal copper on seagrass ecosystems, on a short-term basis. Seagrass Zostera noltei was exposed to two pH levels (8.36 and 8.03) and three copper levels (nominal concentrations, <3, 30 and 300 µg Cu L-1) in a factorial design during 21 days, while Gammarus locusta amphipods were continuously fed with the treated seagrass leaves. We found that the toxicity and bioconcentration of copper in seagrasses were not affected by pH, yet complex copper-pH interactions were observed in the seagrass photosynthesis. We demostrated that seagrasses can act as a copper source in the food web via direct consumption by herbivores. Future research need to investigate the interactive effects on a long-term basis, and to include biochemical and molecular endpoints to provide additional insights to the complex phisiological interactions observed.


Assuntos
Anfípodes/metabolismo , Cobre/toxicidade , Poluentes Químicos da Água/toxicidade , Zosteraceae/fisiologia , Anfípodes/efeitos dos fármacos , Animais , Disponibilidade Biológica , Cobre/farmacocinética , Ecossistema , Ecotoxicologia/métodos , Cadeia Alimentar , Herbivoria , Concentração de Íons de Hidrogênio , Oceanos e Mares , Fotossíntese/efeitos dos fármacos , Água do Mar/química , Oligoelementos , Poluentes Químicos da Água/farmacocinética , Zosteraceae/efeitos dos fármacos
15.
Sci Total Environ ; 685: 315-323, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31176218

RESUMO

Ionic liquids (ILs) are massively used in multiple fields of industry, and consequently, they have entered the environment and become potential threats to the respective ecosystems. In this paper, the toxicity of two different cationic types of ILs (1-hexyl-3-methyl pyridine chloride ([C6Py]Cl) and 1-hexyl-3-methyl imidazole chloride ([C6MIM]Cl)) to Chlorella pyrenoidosa (C. pyrenoidosa) was investigated. Growth inhibition increased with increasing ILs concentrations. C. pyrenoidosa showed a certain recovery at low ILs concentrations, the growth inhibition decreased from 6.13% to 1.57% of the control from 24 h to 96 h, respectively, in 0.5 mg/L [C6MIM]Cl treatment. However, growth inhibition was negatively related with exposure time at high concentrations, and the strongest toxic effects were observed after 48 h. The IC50 values (half inhibitory concentration) were 8.47, 6.65, 6.91 and 7.11 mg/L of [C6MIM]Cl, respectively, in 24, 48, 72, and 96 h, and were 9.05, 6.83, 7.79 and 8.14 mg/L of [C6Py]Cl, respectively. Chlorophyll content declined with higher concentrations of the ILs. The values of chlorophyll fluorescence parameters: the maximum effective quantum yield of photosystem II (PSII) (Fv/Fm), maximum quantum yield in PSII (Fv/F0), and photosynthetic efficiency in PSII (Y(II)), decreased, whereas the minimal fluorescence (F0) increased following the ILs treatment, indicating damage to the photosystem II. [C6MIM]Cl and [C6Py]Cl caused deformation of algae cells, plasmolysis, and damage of the cell membrane and cell wall, and affected organelle structure. Reactive oxygen species (ROS) concentrations increased with higher ILs concentrations from, and superoxide dismutase and catalase activity first increased and then decreased, indicating that the antioxidant defense system was activated to counteract ROS. ROS was the main stress in C. pyrenoidosa induced by ILs, and compared with [C6Py]Cl, [C6MIM]Cl were more toxic to C. pyrenoidosa.


Assuntos
Chlorella/fisiologia , Líquidos Iônicos/toxicidade , Poluentes Químicos da Água/toxicidade , Cátions , Clorofila , Cloreto de Metila , Fotossíntese/efeitos dos fármacos , Complexo de Proteína do Fotossistema II , Superóxido Dismutase/metabolismo
16.
Plant Physiol Biochem ; 140: 27-42, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31078782

RESUMO

Drought is one of most important limiting factors in wheat productivity worldwide. The need to increase drought tolerance during anthesis is of the utmost importance for high yield potentials and yield stability. Photosynthesis is one of the major physiological processes affected by drought. Damages in the photosynthetic apparatus may also arise due to non-regulated dissipation of excessive energy. Zinc (Zn) is an indispensable micronutrient for plants and is required for a wide range of physiological and biochemical processes. In this work we evaluated the stress mitigation effects of Zn seed priming alone and coupled with Zn foliar application in wheat plants submitted to severe drought during anthesis, followed by a recovery period. Under such severe drought stress, photosynthesis was constrained by both stomatal and non-stomatal limitation. Severe drought also induced an increase in non-regulated energy dissipation and hindered a full recovery of the plant's photosynthetic processes after rewatering. We also report possible activation of transposable elements due to drought stress and Zn application. Yield was severely decreased by drought and Zn treatments were unable to counteract this effect. Although unable to oppose the reduction of net photosynthesis, Zn treatments positively enhance photoprotection. At the end of drought period, Zn priming alone and coupled with Zn foliar application increased, respectively, over 2- and 3- fold the regulated dissipation of excess energy. Zn treatments lessened the non-regulated energy dissipation caused by drought, protected the plants against irreversible damages to the photosynthetic apparatus and enabled a better recovery of wheat plants after stress relief.


Assuntos
Secas , Triticum/fisiologia , Zinco/farmacologia , Fotossíntese/efeitos dos fármacos , Estresse Fisiológico , Triticum/efeitos dos fármacos
17.
Plant Physiol Biochem ; 140: 43-54, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31078783

RESUMO

- Salinity is a major threat to agriculture. However, depending on the concentration of soluble salts in soil, increased secondary metabolite levels can occur with no major damages to plant growth and development. The phytoecdysteroid (PE) 20-hydroxyecdysone (20E) is a secondary metabolite with biotechnological, medicinal, pharmaceutical and agrochemical applicability. Here, we characterize the responses (growth and physiology) of Pfaffia glomerata under different NaCl concentrations and examine the production of 20E as affected by salinity. Forty-day-old plants grown in greenhouse were exposed to 0, 120, 240, 360 or 480 mM of NaCl for 11 days. Moderate salinity (i.e., 120 mM of NaCl) led to increased 20E concentrations in leaves (47%) relative to the control with no significant effect on photosynthesis and biomass accumulation, thus allowing improved 20E contents on a per whole-plant basis. In contrast, plants under high salinity (i.e., 240-480 mM of NaCl) displayed similar 20E concentrations in leaves compared to the control, but with marked impairments to biomass accumulation and photosynthetic performance (coupled with decreased sucrose and starch levels) in parallel to nutritional imbalance. High salinity also strongly increased salicylic acid levels, antioxidant enzyme activities, and osmoregulatory status. Regardless of stress severity, 20E production was accompanied by the upregulation of Spook and Phantom genes. Our findings suggest that P. glomerata cultivation in moderate salinity soils can be considered as a suitable agricultural option to increase 20E levels, since metabolic and structural complexity that makes its artificial synthesis very difficult.


Assuntos
Panax/metabolismo , Cloreto de Sódio/farmacologia , Biomassa , Ecdisterona/metabolismo , Fotossíntese/efeitos dos fármacos , Salinidade
18.
Aquat Toxicol ; 212: 138-145, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31125791

RESUMO

Multiple antibiotics are simultaneously detected in aquatic environment, so it is extremely important to study the combined effects of their mixtures. In this study, we investigated the toxic effects of erythromycin (ERY) and enrofloxacin (ENR), added individually or in combination, on Chlorella vulgaris and explored the toxic mechanisms. Results showed that the 96 h-EC50 values of ERY, ENR and ERY-ENR mixture to C. vulgaris were 85.7, 124.5 and 39.9 µg L-1 respectively, and combined toxicity assessment found that joint effect of the two antibiotics was synergism, which was proven by the chlorophyll content in algae. Antioxidant defense system and photosynthesis were involved in toxic mechanisms and the results revealed that both the activities of antioxidant enzymes, and the malondialdehyde (MDA) and glutathione (GSH) contents increased in antibiotic treatments. In addition, the increase was more significant in joint exposure treatment, which implied that the antioxidant defense system was synergistically affected. RT-PCR showed that ERY and ENR upregulated the transcript abundance of psaB, psbC and chlB at low concentrations and the transcription abundance was synergistically increased in combined treatment. Therefore, the risk of the toxicity of antibiotics to aquatic organisms in real environment both at organismal and molecular level increases as a result of their combined presence.


Assuntos
Antioxidantes , Chlorella vulgaris/efeitos dos fármacos , Enrofloxacina/toxicidade , Eritromicina/toxicidade , Transcrição Genética/efeitos dos fármacos , Antibacterianos/farmacologia , Chlorella vulgaris/enzimologia , Chlorella vulgaris/genética , Clorofila/metabolismo , Sinergismo Farmacológico , Ativação Enzimática/efeitos dos fármacos , Glutationa/metabolismo , Malondialdeído , Fotossíntese/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade
19.
Environ Pollut ; 251: 573-580, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31108290

RESUMO

Nonylphenols are endocrine-disrupting chemicals that are used in various industries and are constantly discharged into the terrestrial environment. However, there have been few studies on the phytotoxicity of this chemical in the soil environment. In this study, mung bean (Vigna radiata) and rice (Oryza sativa) were grown in soil containing nonylphenol for 14 and 21 days (reflecting acute and chronic exposure, respectively), and we evaluated physiological responses (chlorophyll content, photosynthetic activity, and stomatal opening size) as well as changes in plant growth (shoot growth and root development) in crop plants grown in soil containing nonylphenol. In mung bean, chlorophyll content and stomata size decreased by exposure to nonylphenol. The decrease in chlorophyll content was attributed to electrolyte leakage due to damage of membrane barrier with increase of cell permeability caused by nonylphenol. Moreover, necrosis of the leaves of mung bean was observed at 2000 mg/kg soil. In rice, shoot growth, chlorophyll content and root development were reduced by chronic exposure to nonylphenol at 2000 mg/kg. Although the exposure concentrations were higher and nonylphenols are non-persistent, their constant release into soil poses a risk to terrestrial ecosystems. Our findings provide information that can be useful for soil ecological risk assessment for nonylphenol in agricultural practices.


Assuntos
Produtos Agrícolas/efeitos dos fármacos , Disruptores Endócrinos/toxicidade , Fenóis/toxicidade , Poluentes do Solo/toxicidade , Solo/química , Clorofila/metabolismo , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/metabolismo , Modelos Teóricos , Fotossíntese/efeitos dos fármacos
20.
Ecotoxicol Environ Saf ; 180: 656-667, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31136876

RESUMO

Owing to the active use of rare-earth elements in many areas, it is necessary to study their behavior in the environment and their biological impact on plants. Despite the role of melatonin and sulfur in plant growth, development and abiotic stress tolerance; it is still not clear how they have a strong regulatory influence and synergistic effect on growth, physiological and biochemical characteristics of plants under different environmental stresses. Therefore, this study highlights how melatonin and sulfur together potentially involved in a reversal of lanthanum-inhibited photosynthetic and growth responses in tomato seedlings. Here, we reported that seedlings grown in a medium containing 150 µM lanthanum exhibited increased overproduction of reactive oxygen species (ROS) and lipid peroxidation together with increased Chlorophyll degradation, and activity of chlorophyllase, proline dehydrogenase and glycolate oxidase (GOx), and decreased photosynthesis and growth. However, the application of melatonin and sulfur showed significant responses on tomato seedlings, although the response of their combined treatment was more effective by further increasing photosynthesis and growth under lanthanum toxicity. Melatonin supplied with sulfur suppressed ROS formation, lipid peroxidation and activity of GOx, and increased photosynthesis by upregulating activities of carbonic anhydrase and ribulose-1,5-bisphosphate carboxylase/oxygenase. Also, sulfur supplementation with melatonin to seedlings resulted in an elevation in the accumulation of Chl and proline by increasing δ-aminolevulinic acid and activity of δ-aminolevulinic acid dehydratase and Δ1-pyrroline-5-carboxylate synthetase activity. The administration of melatonin with sulfur substantially induced upregulation of enzymes (superoxide dismutase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase and glutathione reductase) activities involved in the antioxidant system, thereby mitigating ROS-induced oxidative damage. Thus, this study provides strong evidence that melatonin and sulfur have strong regulatory influence and synergistic role in alleviating the adverse effect of lanthanum-toxicity by increasing photosynthesis and growth.


Assuntos
Poluentes Ambientais/toxicidade , Lantânio/toxicidade , Lycopersicon esculentum/efeitos dos fármacos , Melatonina/farmacologia , Enxofre/farmacologia , Antioxidantes/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/metabolismo , Fotossíntese/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo
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