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Changes in pigment concentration and composition in Norway spruce induced by long-term exposure to low levels of ozone.
1995
Mikkelsen T.N. | Dodell B. | Lutz C.
Altered stomatal dynamics of two Euramerican poplar genotypes submitted to successive ozone exposure and water deficit النص الكامل
2019
Dusart, Nicolas | Vaultier, Marie-Noëlle | Olry, Jean-Charles | Buré, Cyril | Gérard, Joëlle | Jolivet, Yves | Le Thiec, Didier | SILVA (SILVA) ; Institut National de la Recherche Agronomique (INRA)-AgroParisTech-Université de Lorraine (UL) | ANR-12-LABXARBRE-01
The impact of ozone (O3) pollution events on the plant drought response needs special attention because spring O3 episodes are often followed by summer drought. By causing stomatal sluggishness, O3 could affect the stomatal dynamic during a subsequent drought event. In this context, we studied the impact of O3 exposure and water deficit (in the presence or in the absence of O3 episode) on the stomatal closure/opening mechanisms relative to irradiance or vapour pressure deficit (VPD) variation. Two genotypes of Populus nigra x deltoides were exposed to various treatments for 21 days. Saplings were exposed to 80 ppb/day O3 for 13 days, and then to moderate drought for 7 days. The curves of the stomatal response to irradiance and VPD changes were determined after 13 days of O3 exposure, and after 21 days in the case of subsequent water deficit, and then fitted using a sigmoidal model. The main responses under O3 exposure were stomatal closure and sluggishness, but the two genotypes showed contrasting responses. During stomatal closure induced by a change in irradiance, closure was slower for both genotypes. Nonetheless, the genotypes differed in stomatal opening under light. Carpaccio stomata opened more slowly than control stomata, whereas Robusta stomata tended to open faster. These effects could be of particular interest, as stomatal impairment was still present after O3 exposure and could result from imperfect recovery. Under water deficit alone, we observed slower stomatal closure in response to VPD and irradiance, but faster stomatal opening in response to irradiance, more marked in Carpaccio. Under the combined treatment, most of the parameters showed antagonistic responses. Our results highlight that it is important to take genotype-specific responses and interactive stress cross-talk into account to improve the prediction of stomatal conductance in response to various environmental modifications.
اظهر المزيد [+] اقل [-]Altered stomatal dynamics of two Euramerican poplar genotypes submitted to successive ozone exposure and water deficit النص الكامل
2019
Dusart, Nicolas | Vaultier, Marie-Noëlle | Olry, Jean-Charles | Buré, Cyril | Gérard, Joëlle | Jolivet, Yves | Le Thiec, Didier | SILVA (SILVA) ; Institut National de la Recherche Agronomique (INRA)-AgroParisTech-Université de Lorraine (UL) | ANR-12-LABXARBRE-01
The impact of ozone (O3) pollution events on the plant drought response needs special attention because spring O3 episodes are often followed by summer drought. By causing stomatal sluggishness, O3 could affect the stomatal dynamic during a subsequent drought event. In this context, we studied the impact of O3 exposure and water deficit (in the presence or in the absence of O3 episode) on the stomatal closure/opening mechanisms relative to irradiance or vapour pressure deficit (VPD) variation. Two genotypes of Populus nigra x deltoides were exposed to various treatments for 21 days. Saplings were exposed to 80 ppb/day O3 for 13 days, and then to moderate drought for 7 days. The curves of the stomatal response to irradiance and VPD changes were determined after 13 days of O3 exposure, and after 21 days in the case of subsequent water deficit, and then fitted using a sigmoidal model. The main responses under O3 exposure were stomatal closure and sluggishness, but the two genotypes showed contrasting responses. During stomatal closure induced by a change in irradiance, closure was slower for both genotypes. Nonetheless, the genotypes differed in stomatal opening under light. Carpaccio stomata opened more slowly than control stomata, whereas Robusta stomata tended to open faster. These effects could be of particular interest, as stomatal impairment was still present after O3 exposure and could result from imperfect recovery. Under water deficit alone, we observed slower stomatal closure in response to VPD and irradiance, but faster stomatal opening in response to irradiance, more marked in Carpaccio. Under the combined treatment, most of the parameters showed antagonistic responses. Our results highlight that it is important to take genotype-specific responses and interactive stress cross-talk into account to improve the prediction of stomatal conductance in response to various environmental modifications.
اظهر المزيد [+] اقل [-]Nickel decorated manganese oxynitride over graphene nanosheets as highly efficient visible light driven photocatalysts for acetylsalicylic acid degradation النص الكامل
2021
Mohan, Harshavardhan | Yoo, Suhwan | Thimmarayan, Srivalli | Oh, Hyeon Seung | Kim, Gitae | Seralathan, Kamala-Kannan | Shin, Taeho
In this work, we prepared nanocomposites of nickel-decorated manganese oxynitride on graphene nanosheets and demonstrated them as photocatalysts for degradation of acetylsalicylic acid (ASA). The catalyst exhibited a high degradation efficiency over ASA under visible light irradiation and an excellent structural stability after multiple uses. Compared to manganese oxide (MnO) and manganese oxynitride (MnON) nanoparticles, larger specific surface area and smaller band gap were observed for the nanocomposite accounting for the enhanced photocatalytic efficiency. Besides the compositional effect of the catalyst, we also examined the influence of various experimental parameters on the degradation of ASA such as initial concentration, catalyst dose, initial pH and additives. The best performance was obtained for the nanocomposite when the catalyst dose was 10 mg/mL and the initial pH 3. Detection of intermediates during photocatalysis showed that ASA undergoes hydroxylation, demethylation, aromatization, ring opening, and finally complete mineralization into CO₂ and H₂O by reactive species. For practical applications as a photocatalyst, cytotoxicity of the nanocomposite was also evaluated, which revealed its insignificant impact on the cell viability. These results suggest the nanocomposite of nickel-decorated manganese oxynitride on graphene nanosheets as a promising photocatalyst for the remediation of ASA-contaminated water.
اظهر المزيد [+] اقل [-]Emerging 2D/0D g-C3N4/SnO2 S-scheme photocatalyst: New generation architectural structure of heterojunctions toward visible-light-driven NO degradation النص الكامل
2021
Van Pham, Viet | Mai, Diem-Quynh | Bui, Dai-Phat | Van Man, Tran | Zhu, Bicheng | Zhang, Liuyang | Sangkaworn, Jariyaporn | Tantirungrotechai, Jonggol | Reutrakul, Vichai | Cao, Thi Minh
Enhancing and investigating the photocatalytic activity over composites for new models remains a challenge. Here, an emerging S-scheme photocatalyst composed of 2D/0D g-C₃N₄ nanosheets-assisted SnO₂ nanoparticles (g-C₃N₄/SnO₂) is successfully synthesized and used for degrading nitrogen oxide (NO), which causes negative impacts on the environment. A wide range of characterization techniques confirms the successful synthesis of SnO₂ nanoparticles, g-C₃N₄ nanosheets, and 2D/0D g-C₃N₄/SnO₂ S-scheme photocatalysts via hydrothermal and annealing processes. Besides, the visible-light response is confirmed by optical analysis. The S-scheme charge transfer was elucidated by Density-Functional Theory (DFT) calculation, trapping experiments, and electron spin resonance (ESR). We found that intrinsic oxygen vacancies of SnO₂ nanoparticles and S-scheme charge transfer addressed the limitation of other heterojunction types. It is notable that compared pure SnO₂ nanoparticles and g-C₃N₄, g-C₃N₄/SnO₂ offered the best photocatalytic NO degradation and photostability under visible light with the removal of more than 40% NO at 500 ppb throughout the experiment. Benefiting from the unique structural features, the new generation architectural structure of S-scheme heterojunction exhibited potential photocatalytic activity and it would simultaneously act more promising for environmental treatment in the coming years.
اظهر المزيد [+] اقل [-]Enhanced photocatalytic activity of ZnO/g-C3N4 composites by regulating stacked thickness of g-C3N4 nanosheets النص الكامل
2020
Gao, Xingxing | Yang, Binzheng | Yao, Wenqing | Wang, Yajun | Zong, Ruilong | Wang, Jian | Li, Xianchun | Jin, Wenjie | Tao, Dongping
A self-assembly method was adopted to synthesize loading architecture of ZnO/g-C₃N₄ heterojunction composites by hybridization of g-C₃N₄ nanosheets and ZnO nanoparticles utilizing a refluxing method at a low temperature. More importantly, we provided a novel route to regulate the π-π restacking thickness of the g-C₃N₄ nanosheets among ZnO/g-C₃N₄ composites by the controlling the refluxing time in the ethanol solution, which can optimize the surface hybrid structure, optical response and photocatalytic activity. Among all of samples, ZnO/g-C₃N₄ composites with a refluxing 12 h showed the enhancement of photocatalytic activity. The enhanced visible light photocatalytic activity of ZCN-12 composites can be ascribed to the synergistic effects of the construction of hybrid structures, reduction of structural defects of g-C₃N₄ nanosheets and suitable π-π restacking g-C₃N₄ nanosheets loading thickness.
اظهر المزيد [+] اقل [-]Effective oxidation of methyl parathion pesticide in water over recycled glass based-MCM-41 decorated by green Co3O4 nanoparticles النص الكامل
2020
Salam, Mohamed Abdel | AbuKhadra, Mostaf R. | Mohamed, Aya S.
Pieces of glass as solid wastes were recycled in the synthesis of highly order MCM-41 that decorated by green fabricated Co₃O₄ nanoparticles using the green extract of green tea leaves forming novel green nano-composite. The synthetic Co₃O₄/MCM-41 exhibit high surface area, low bandgap energy (1.63 eV), and typical spherical morphology decorated by Co₃O₄ nanoparticles. The composite was evaluated as green photocatalyst in effective oxidation of methyl parathion pesticide in the presence of a visible light source. The degradation results revealed complete removal of 50 mg/L and 100 mg/L after 60 min and 90 min, respectively using 0.25 of the catalyst at pH 8. The detection of the TOC in the treated methyl parathion solution gives strong indications about the formation of organic intermediate compounds during the oxidation steps. The main detected intermediate compound are C₆H₅OH(NO₂), C₆H₅OH, (CH₃O)₃P(S), C₆H₄(OH)₂, C₆H₃(OH)₃, C₆H₄(NH₂)OP(O)(OCH₃)₂, (CH₃O)₂P(O)OH, (CH₂)₂C(OH)OH(CHO)OC(O), and HO₂C(CH₂)₂C(O)CHO. The detected intermediate compounds converted into SO₄²⁻, PO₄³⁻, NO₃⁻, and CO₂ under the extensive photocatalytic of them over Co₃O₄/MCM-41. The oxidizing species trapping test verified the controlling of the methyl parathion degradation pathway by the hydroxyl radicals. Finally, the composite showed significant reusability properties and applied five times in the oxidation of methyl parathion with considerable degradation percentages.
اظهر المزيد [+] اقل [-]Heterogeneous photo-Fenton degradation of formaldehyde using MIL-100(Fe) under visible light irradiation النص الكامل
2019
Mohammadifard, Zahra | Saboori, Rahmatallah | Mirbagheri, Naghmeh Sadat | Sabbaghi, Samad
Removal of toxic formaldehyde from environmental waters is crucial to maintain ecosystem sustainability and human health. In this work, MIL-100(Fe) as a heterogeneous Fenton-like photocatalyst was used for the treatment of formaldehyde-contaminated water. The MIL-100(Fe) was synthesized via a facile solvothermal method and fully characterized using different spectroscopic and microscopic techniques. Based on the results, the formation of highly porous, crystalline, and stable visible light-responsive MIL-100(Fe) was confirmed. The Fenton-like photocatalytic efficiency of the MIL-100(Fe) toward the degradation of formaldehyde was then studied under visible light irradiation. For this purpose, the effect of initial concentration of formaldehyde, photocatalyst dose, H₂O₂ concentration, solution pH, and contact time on the removal efficiency of the MIL-100(Fe) was investigated using central composite design. The obtained results showed that the removal efficiency of the MIL-100(Fe) is significantly affected by the initial concentration of formaldehyde. A second-order model with R² = 0.93 was developed for the system that was able to adequately predict the percentage removal of formaldehyde by the MIL-100(Fe) under different experimental conditions. According to the numerical optimization results, by using 1.13 g L⁻¹ photocatalyst and 0.055 mol L⁻¹ H₂O₂, 93% of formaldehyde can be removed after 119 min from an aqueous solution containing 700 mg L⁻¹ of formaldehyde at pH 6.54.
اظهر المزيد [+] اقل [-]Personality and artificial light at night in a semi-urban songbird population: No evidence for personality-dependent sampling bias, avoidance or disruptive effects on sleep behaviour النص الكامل
2018
Raap, Thomas | Thys, Bert | Grunst, Andrea S. | Grunst, Melissa L. | Pinxten, Rianne | Eens, Marcel
Light pollution or artificial light at night (ALAN) is an increasing, worldwide challenge that affects many aspects of animal behaviour. Interestingly, the response to ALAN varies widely among individuals within a population and variation in personality (consistent individual differences in behaviour) may be an important factor explaining this variation. Consistent individual differences in exploration behaviour in particular may relate to the response to ALAN, as increasing evidence indicates its relation with how individuals respond to novelty and how they cope with anthropogenic modifications of the environment. Here, we assayed exploration behaviour in a novel environment as a proxy for personality variation in great tits (Parus major). We observed individual sleep behaviour over two consecutive nights, with birds sleeping under natural dark conditions the first night and confronted with ALAN inside the nest box on the second night, representing a modified and novel roosting environment. We examined whether roosting decisions when confronted with a camera (novel object), and subsequently with ALAN, were personality-dependent, as this could potentially create sampling bias. Finally, we assessed whether experimentally challenging individuals with ALAN induced personality-dependent changes in sleep behaviour.Slow and fast explorers were equally likely to roost in a nest box when confronted with either a camera or artificial light inside, indicating the absence of personality-dependent sampling bias or avoidance of exposure to ALAN. Moreover, slow and fast explorers were equally disrupted in their sleep behaviour when challenged with ALAN. Whether other behavioural and physiological effects of ALAN are personality-dependent remains to be determined. Moreover, the sensitivity to disturbance of different behavioural types might depend on the behavioural context and the specific type of challenge in question. In our increasingly urbanized world, determining whether the effects of anthropogenic stressors depend on personality type will be of paramount importance as it may affect population dynamics.
اظهر المزيد [+] اقل [-]Effects of ozone on stomatal responses to environmental parameters (blue light, red light, CO2 and vapour pressure deficit) in three Populus deltoides × Populus nigra genotypes النص الكامل
2013
Dumont, Jenny | Spicher, Fabien | Montpied, Pierre | Dizengremel, Pierre | Jolivet, Yves | Le Thiec, Didier
Effects of ozone on stomatal responses to environmental parameters (blue light, red light, CO2 and vapour pressure deficit) in three Populus deltoides × Populus nigra genotypes النص الكامل
2013
Dumont, Jenny | Spicher, Fabien | Montpied, Pierre | Dizengremel, Pierre | Jolivet, Yves | Le Thiec, Didier
The effect of ozone (O3) on stomatal regulation was studied in three Euramerican poplar genotypes (Populus deltoides × Populus nigra: Carpaccio, Cima and Robusta). The impact of O3 on stomatal conductance responses to variations in blue light, red light, CO2 concentration and vapour pressure deficit (VPD) was studied. Upon O3 exposure, a sluggish response of stomatal movements was observed, characterized by slower reactions to increases in blue light intensity, CO2 concentration and VPD, and lower amplitude of the response to variations in light intensity. That sluggish response should be taken into account in stomatal conductance models for phytotoxic ozone dose (PODY) calculations. The speed of the response to variations in environmental parameters appears as a determining factor of genotype-related sensitivity.
اظهر المزيد [+] اقل [-]Effects of ozone on stomatal responses to environmental parameters (blue light, red light, CO2 and vapour pressure deficit) in three Populus deltoides × Populus nigra genotypes النص الكامل
2013
Dumont, Jennifer | Spicher, Fabien | Montpied, Pierre | Dizengremel, Pierre | Jolivet, Yves | Le Thiec, Didier
The effect of ozone (O3) on stomatal regulation was studied in three Euramerican poplar genotypes (Populus deltoides Populus nigra: Carpaccio, Cima and Robusta). The impact of O3 on stomatal conductance responses to variations in blue light, red light, CO2 concentration and vapour pressure deficit (VPD) was studied. Upon O3 exposure, a sluggish response of stomatal movements was observed, characterized by slower reactions to increases in blue light intensity, CO2 concentration and VPD, and lower amplitude of the response to variations in light intensity. That sluggish response should be taken into account in stomatal conductance models for phytotoxic ozone dose (PODY) calculations. The speed of the response to variations in environmental parameters appears as a determining factor of genotyperelated sensitivity.
اظهر المزيد [+] اقل [-]