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2.
Eur J Appl Physiol ; 124(1): 343-352, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37517068

RESUMO

PURPOSE: Polluted environments can adversely affect lung function and exercise performance. Evidence suggests that some nutrient supplements may offset pollution's detrimental effects. This study examined the effect of polyphenol supplementation on lung function and exercise performance in an ozone-polluted environment. METHODS: Ten male cyclists (mean ± SD: age, 43.8 ± 12.4 years; height, 177.8 ± 7.1 cm; weight, 76.03 ± 7.88 kg; VO2max 4.12 ± 0.72 L min-1) initially completed a baseline maximal incremental test and maximal effort 4 km time trial in ambient air. Thereafter cyclists completed two trials in an ozone-polluted environment (0.25 ppm) following seven days of supplementation with either polyphenol (PB) or placebo (PL). Experimental trials consisted of a three-stage submaximal test (50%, 60% and 70% incremental peak power) followed by a 4 km time trial. Lung function was measured pre- and post-exercise via spirometry and adverse respiratory symptoms with a Likert scale. RESULTS: Ozone exposure significantly reduced (p < 0.05) lung function relative to ambient air. There were no significant differences (p > 0.05) in measured variables across the three submaximal intensities. There was a small (d = 0.31) non-significant difference (p = 0.09) in 4 km performance in PB (406.43 ± 50.29 s) vs. PL (426.20 ± 75.06 s). Oxygen consumption during the time trial was greater in PB (3.49 ± 0.71 L min-1) vs PL (3.32 ± 0.71 L min-1, p = 0.01, d = 0.24). Cough severity (SOC) was lower (p = 0.03) with PB relative to PL. CONCLUSION: PB supplementation may provide small benefits to performance and reduce cough symptoms during high-intensity exercise in ozone-polluted environments.


Assuntos
Desempenho Atlético , Ozônio , Adulto , Humanos , Masculino , Pessoa de Meia-Idade , Ciclismo , Tosse/induzido quimicamente , Suplementos Nutricionais , Pulmão , Consumo de Oxigênio , Ozônio/efeitos adversos , Pós
3.
Ther Adv Respir Dis ; 17: 17534666231186726, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37646293

RESUMO

BACKGROUND: There have been 26 epidemic thunderstorm asthma (ETSA) events worldwide, with Melbourne at the epicentre of ETSA with 7 recorded events, and in 2016 experienced the deadliest ETSA event ever recorded. Health services and emergency departments were overwhelmed with thousands requiring medical care for acute asthma and 10 people died. OBJECTIVES: This multidisciplinary study was conducted across various health and science departments with the aim of improving our collective understanding of the mechanism behind ETSA. DESIGN: This study involved time-resolved analysis of atmospheric sampling of the air for pollen and fungal spores, and intact and ruptured pollen compared with different weather parameters, pollution levels and clinical asthma presentations. METHODS: Time-resolved pollen and fungal spore data collected by Deakin AirWATCH Burwood, underwent 3-h analysis, to better reflect the 'before', 'during' and 'after' ETSA time points, on the days leading up to and following the Melbourne 2016 event. Linear correlations were conducted with atmospheric pollution data provided by the Environment Protection Authority (EPA) of Victoria, weather data sourced from Bureau of Meteorology (BOM) and clinical asthma presentation data from the Victorian Agency for Health Information (VAHI) of Department of Health. RESULTS: Counts of ruptured grass pollen grains increased 250% when the thunderstorm outflow reached Burwood. Increased PM10, high relative humidity, decreased temperature and low ozone concentrations observed in the storm outflow were correlated with increased levels of ruptured grass pollen. In particular, high ozone levels observed 6 h prior to this ETSA event may be a critical early indicator of impending ETSA event, since high ozone levels have been linked to increasing pollen allergen content and reducing pollen integrity, which may in turn contribute to enhanced pollen rupture. CONCLUSION: The findings presented in this article highlight the importance of including ruptured pollen and time-resolved analysis to forecast ETSA events and thus save lives.


Assuntos
Asma , Ozônio , Humanos , Alérgenos , Pólen , Asma/epidemiologia , Asma/etiologia , Tempo (Meteorologia) , Ozônio/efeitos adversos
4.
Skin Pharmacol Physiol ; 36(4): 195-204, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36927995

RESUMO

INTRODUCTION: Along with climate changes, we see an increase in allergic symptoms and the number of pollen-allergic patients in many countries. Increased allergic symptoms are associated with an elevated ozone exposure which may be linked by impaired epithelial barrier function. This study aimed to quantify the clinical effect of ozone and pollen double exposure (DE). We tested whether ozone impairs barrier-related skin physiology and mucosal functions under DE with pollen in grass pollen-allergic patients versus healthy controls. METHODS: This case-control study included 8 grass pollen-allergic patients and 8 non-allergic healthy subjects exposed to grass pollen and ozone in the GA2LEN pollen chamber, comparing shorter and longer DE duration. Non-invasive skin physiological parameters were assessed, including stratum corneum hydration, skin redness, surface pH, and basal transepidermal water loss as a parameter for epidermal barrier function. The subjects' general well-being, bronchial, nasal, and ocular symptoms were documented. RESULTS: Skin physiology tests revealed that DE in allergic patients deteriorates the epidermal barrier function and increases the surface pH and skin redness. DE significantly induced nasal secretion in pollen-allergic versus healthy subjects, which was more pronounced with longer DE. The general well-being was significantly impaired under DE versus pollen or ozone alone, with a negative influence of DE duration. No relevant bronchial symptoms were recorded. CONCLUSION: Skin physiology and nasal mucosal symptoms are negatively affected by ozone and grass pollen DE in allergic patients. The negative effects showed, in some parameters, a dose (time)-response relationship. The pH can be regarded as a possible modulatory mechanism.


Assuntos
Hipersensibilidade , Ozônio , Rinite Alérgica Sazonal , Humanos , Rinite Alérgica Sazonal/induzido quimicamente , Rinite Alérgica Sazonal/diagnóstico , Estudos de Casos e Controles , Poaceae/efeitos adversos , Pólen , Hipersensibilidade/diagnóstico , Ozônio/efeitos adversos , Alérgenos
5.
Int J Rheum Dis ; 26(8): 1590-1593, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36814395

RESUMO

Ozone therapy is a minimally invasive technique now widely used for the treatment of pain due to herniated discs. In literature there are conflicting results concerning its real effectiveness and few data about its possible complications. In this case report we present a case of spondylodiscitis, septic arthritis and gluteal abscess following the execution of 4 sessions of ozone therapy. Given the impossibility of isolating the etiological agent, an empirical antibiotic therapy with an overall duration of 6 weeks was set up, initially with daptomycin and ceftriazone, to which was added after 2 days metronidazole, administered intravenously; after 20 days the cephalosporin was replaced with oral amoxicillin/clavulanate. Neridronate was added to treat bone edema and to avoid bone erosion. The patient showed improvement of both clinical conditions and inflammation indexes, and was discharged after 4 weeks without further complications at follow-up. Few cases are reported in the literature about spondylodiscitis secondary to ozone treatment, and just 1 case is described about the use of neridronate as additive drug to antibiotic treatment in spondylodiscitis to avoid bone disruption and surgery complications.


Assuntos
Discite , Dor Lombar , Ozônio , Sacroileíte , Humanos , Discite/diagnóstico , Discite/tratamento farmacológico , Discite/etiologia , Abscesso/diagnóstico , Abscesso/tratamento farmacológico , Abscesso/etiologia , Antibacterianos/uso terapêutico , Dor Lombar/diagnóstico , Dor Lombar/tratamento farmacológico , Dor Lombar/etiologia , Ozônio/efeitos adversos , Vértebras Lombares/diagnóstico por imagem
6.
Knee ; 35: 114-123, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35306352

RESUMO

BACKGROUND: Osteoarthritis (OA) is a joint disease of multifactorial etiology, affecting mainly the knees. We aimed to evaluate the effects of two different doses of gaseous ozone intra-articularly on the knee cartilage morphology of rats with osteoarthritis (OA). METHODS: The articular lesion was induced by sodium monoiodoacetate (MIA). 40 Wistar rats were divided into 4 groups: G1 control (without lesion and without treatment), G2 articular lesion (AL) (only lesion MIA-induced), G3 AL + treatment with 5 µg/mL of ozone intra-articular, and G4 AL + treatment with 10 µg/mL of ozone intra-articular. The experiment was carried out for 60 days. RESULTS: Both doses of ozone intra-articular demonstrated less reduction in joint space (G3 and G4) compared to the G2, formation of osteophytes, but without subchondral sclerosis. Ozone decreased the volumetric density of the articular lesion (VV(AL)) of tibial. The treatments recovered VV(AL) of the femur similar to G1. Ozone lower dose (G3) showed lower tibia and femur macroscopic scores. CONCLUSION: Intra-articular gaseous ozone can delay the degeneration of articular cartilage and can represents an integrative therapy in the OA treatment of knee after 60 days of treatment. For the first time the role of ozone in articular cartilage degeneration was evaluated helping to understand this therapy.


Assuntos
Cartilagem Articular , Osteoartrite do Joelho , Osteoartrite , Ozônio , Animais , Cartilagem Articular/patologia , Modelos Animais de Doenças , Humanos , Articulação do Joelho/patologia , Osteoartrite/induzido quimicamente , Osteoartrite/tratamento farmacológico , Osteoartrite do Joelho/induzido quimicamente , Osteoartrite do Joelho/tratamento farmacológico , Osteoartrite do Joelho/patologia , Ozônio/efeitos adversos , Ratos , Ratos Wistar
8.
Front Immunol ; 12: 631092, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33717165

RESUMO

Despite recent advances in using biologicals that target Th2 pathways, glucocorticoids form the mainstay of asthma treatment. Asthma morbidity and mortality remain high due to the wide variability of treatment responsiveness and complex clinical phenotypes driven by distinct underlying mechanisms. Emerging evidence suggests that inhalation of the toxic air pollutant, ozone, worsens asthma by impairing glucocorticoid responsiveness. This review discusses the role of oxidative stress in glucocorticoid resistance in asthma. The underlying mechanisms point to a central role of oxidative stress pathways. The primary data source for this review consisted of peer-reviewed publications on the impact of ozone on airway inflammation and glucocorticoid responsiveness indexed in PubMed. Our main search strategy focused on cross-referencing "asthma and glucocorticoid resistance" against "ozone, oxidative stress, alarmins, innate lymphoid, NK and γδ T cells, dendritic cells and alveolar type II epithelial cells, glucocorticoid receptor and transcription factors". Recent work was placed in the context from articles in the last 10 years and older seminal research papers and comprehensive reviews. We excluded papers that did not focus on respiratory injury in the setting of oxidative stress. The pathways discussed here have however wide clinical implications to pathologies associated with inflammation and oxidative stress and in which glucocorticoid treatment is essential.


Assuntos
Asma/imunologia , Glucocorticoides/uso terapêutico , Inflamação/genética , Neutrófilos/imunologia , Estresse Oxidativo/efeitos dos fármacos , Ozônio/efeitos adversos , Sistema Respiratório/efeitos dos fármacos , Animais , Asma/complicações , Asma/tratamento farmacológico , Asma/patologia , Resistência a Medicamentos , Glucocorticoides/farmacologia , Humanos , Inflamação/imunologia , Camundongos , Neutrófilos/efeitos dos fármacos , Estresse Oxidativo/imunologia
10.
Arch Dermatol Res ; 313(3): 139-146, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32385690

RESUMO

Tropospheric ozone (O3) is a source of oxidative stress. This study examined the ability of a topical antioxidant (WEL-DS) to inhibit O3-mediated damage in a human epidermal skin model. Four groups of tissues (N = 24) were compared: Group 1 (control) were untreated and unexposed; Group 2 were untreated and exposed to O3 (0.4 ppm, 4 h); Group 3 were pretreated with WEL-DS and unexposed; Group 4 were pretreated with WEL-DS and exposed to O3 (0.4 ppm, 4 h). Pretreated tissues were topically treated with 20 uL of WEL-DS and incubated for up to 20 h at 37 °C [humidified, 5% carbon dioxide (CO2)]. After 24 h, tissues were re-treated with WEL-DS and exposed to O3. Tissues were evaluated for Reactive Oxygen Species (ROS), hydrogen peroxide (H2O2), 4-hydroxynonenal (4-HNE) protein adducts, NF-κB p65 response and histology. In O3-exposed groups, WEL-DS significantly inhibited ROS formation vs. untreated tissues (p < 0.05). Pretreatment with WEL-DS inhibited H2O2 production vs. untreated tissues (p < 0.05), and decreased NF-κB p65 transcription factor signal. Oxidative stress induction in O3-exposed tissues was confirmed by increased levels of 4-HNE protein adducts (marker of lipid peroxidation); WEL-DS application reduced this effect. WEL-DS inhibited damage in tissues exposed to O3 with no significant changes in epidermal structure. A comprehensive topical antioxidant significantly diminished O3-induced oxidative damage in a human epidermal skin model.


Assuntos
Antioxidantes/administração & dosagem , Epiderme/efeitos dos fármacos , Ozônio/efeitos adversos , Envelhecimento da Pele/efeitos dos fármacos , Administração Cutânea , Técnicas de Cultura de Células , Células Cultivadas , Avaliação Pré-Clínica de Medicamentos , Epiderme/patologia , Humanos , Peroxidação de Lipídeos/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo
11.
Molecules ; 25(20)2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-33081281

RESUMO

A 'remedy for all' natural product widely known in the Korean Peninsula is called Panax Ginseng Meyer. Globalization represents a persistent risk to the ozone layer, leading to bountiful amounts of Ultra-Violet B beams (UVB). The variety in human skin hues is ascribed to the characteristic color called Melanin. However, Melanin overproduction due to UVB beams promotes skin staining and tumorigenesis, a process called photo aging, which damages skin quality. To assess the effects of Korean Red Ginseng Oil (KGO) on photo aging, the murine melanoma cell lines B16/F10 were used in vitro and HRM-2 hairless mice exposed to UVB were studied in vivo. Our results revealed that KGO reduced tyrosinase activity and melanin production in B16/F10 cells along with the suppression of upstream factors involved in the melanin production pathway, both transcriptionally and transitionally. In the in vivo studies, KGO suppressed the expression of Matrix Metalloproteinase (MMP) and Interleukins along with a reduction of depth in wrinkle formation and reduced collagen degradation. Moreover, the feed intake and feed efficiency ratio that decreased as a result of UVB exposure was also improved by KGO treatment. In light of our results, we conclude that KGO can have considerable benefits due to its various properties of natural skin enhancement.


Assuntos
Carcinogênese/efeitos dos fármacos , Melanoma Experimental/tratamento farmacológico , Panax/química , Óleos de Plantas/farmacologia , Animais , Carcinogênese/efeitos da radiação , Fibroblastos/efeitos dos fármacos , Humanos , Melaninas/biossíntese , Melaninas/efeitos da radiação , Camundongos , Camundongos Pelados , Ozônio/efeitos adversos , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Óleos de Plantas/química , Pele/efeitos dos fármacos , Pele/metabolismo , Raios Ultravioleta/efeitos adversos
12.
Philos Trans A Math Phys Eng Sci ; 378(2183): 20190324, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32981443

RESUMO

Atmospheric reactive nitrogen (Nr) has been a cause of serious environmental pollution in China. Historically, China used too little Nr in its agriculture to feed its population. However, with the rapid increase in N fertilizer use for food production and fossil fuel consumption for energy supply over the last four decades, increasing gaseous Nr species (e.g. NH3 and NOx) have been emitted to the atmosphere and then deposited as wet and dry deposition, with adverse impacts on air, water and soil quality as well as plant biodiversity and human health. This paper reviews the issues associated with this in a holistic way. The emissions, deposition, impacts, actions and regulations for the mitigation of atmospheric Nr are discussed systematically. Both NH3 and NOx make major contributions to environmental pollution but especially to the formation of secondary fine particulate matter (PM2.5), which impacts human health and light scattering (haze). In addition, atmospheric deposition of NH3 and NOx causes adverse impacts on terrestrial and aquatic ecosystems due to acidification and eutrophication. Regulations and practices introduced by China that meet the urgent need to reduce Nr emissions are explained and resulting effects on emissions are discussed. Recommendations for improving future N management for achieving 'win-win' outcomes for Chinese agricultural production and food supply, and human and environmental health, are described. This article is part of a discussion meeting issue 'Air quality, past present and future'.


Assuntos
Poluição do Ar/efeitos adversos , Poluição Ambiental/efeitos adversos , Nitrogênio/efeitos adversos , Chuva Ácida/efeitos adversos , Poluição do Ar/análise , Poluição do Ar/prevenção & controle , Biodiversidade , China , Ecossistema , Meio Ambiente , Poluição Ambiental/análise , Poluição Ambiental/prevenção & controle , Eutrofização , Política de Saúde , Humanos , Ozônio/efeitos adversos , Plantas/efeitos dos fármacos , Espécies Reativas de Nitrogênio/efeitos adversos , Solo/química
15.
Sci Total Environ ; 692: 713-722, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31539979

RESUMO

Nocturnal transpiration may be a key factor influencing water use in plants. Tropospheric ozone (O3) and availability of nutrients such as nitrogen (N) and phosphorus (P) in the soil can affect daytime water use through stomata, but the combined effects of O3, N and P on night-time stomatal conductance (gs) are not known. We investigated the effects of O3 and soil availability of N and P on nocturnal gs and the dynamics of stomatal response after leaf severing in an O3-sensitive poplar clone (Oxford) subjected to combined treatments over a growing season in an O3 free air controlled exposure (FACE) facility. The treatments were two soil N levels (0 and 80 kg N ha-1; N0 and N80), three soil P levels (0, 40 and 80 kg P ha-1; P0, P40 and P80) and three O3 levels (ambient concentration, AA [35.0 ppb as hourly mean]; 1.5 × AA; 2.0 × AA). The analysis of stomatal dynamics after leaf severing suggested that O3 impaired stomatal closure execution. As a result, nocturnal gs was increased by 2.0 × AA O3 in August (+39%) and September (+108%). Night-time gs was correlated with POD0 (phytotoxic O3 dose) and increased exponentially after 40 mmol m-2 POD0. Such increase of nocturnal gs was attributed to the emission of ethylene due to 2.0 × AA O3 exposure, while foliar abscisic acid (ABA) or indole-3-acetic acid (IAA) did not affect gs at night. Interestingly, the O3-induced stomatal opening at night was limited by N treatments in August, but not limited in September. Phosphorus decreased nocturnal gs, although P did not modify the O3-induced stomatal dysfunction. The results suggest that the increased nocturnal gs may be associated with a need to improve N acquisition to cope with O3 stress.


Assuntos
Nitrogênio/fisiologia , Ozônio/efeitos adversos , Fósforo/fisiologia , Estômatos de Plantas/efeitos dos fármacos , Populus/efeitos dos fármacos , Ritmo Circadiano , Fertilizantes/análise , Itália , Estômatos de Plantas/fisiologia , Populus/fisiologia
16.
J Neurol Surg A Cent Eur Neurosurg ; 80(6): 503-506, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31430795

RESUMO

Oxygen-ozone therapy is used to treat degenerative pathology of the spine when surgery is not needed (e.g., removal of a herniated disk). Some authors have described it as a safe and effective procedure in ∼ 70 to 90% of patients. The aim of the therapy is to dehydrate the intervertebral disk and alter its contents. However, this treatment has been associated with some rare but very serious side effects. Both cardiac damage and a case of fulminant septicemia were reported. We describe a case of suspected pulmonary embolism, followed by sudden death, in an elderly woman treated with oxygen-ozone therapy for lumbar pain caused by disk protrusion. We believe a massive pulmonary embolism occurred, probably caused by an intradiskal injection that accidentally punctured a venous vessel and created emboli.


Assuntos
Deslocamento do Disco Intervertebral/terapia , Dor Lombar/terapia , Oxigênio/efeitos adversos , Ozônio/efeitos adversos , Embolia Pulmonar/etiologia , Idoso de 80 Anos ou mais , Feminino , Humanos , Deslocamento do Disco Intervertebral/complicações , Dor Lombar/etiologia , Oxigênio/uso terapêutico , Ozônio/uso terapêutico
18.
J Neuroophthalmol ; 39(4): 518-519, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-30741783

RESUMO

A 34-year-old man with chronic neck pain was treated with regular cervical paravertebral ozone injections. After his last injection, he experienced a syncopal episode and, upon awakening, was found to have ataxia, aphasia, hemiparesis, and left sixth nerve palsy. Computed tomographic angiography demonstrated intra-arterial gas in the right vertebral artery; multiple posterior circulation infarcts were seen on brain MRI. This case illustrates the potential dangers of paravertebral injections of ozone.


Assuntos
Embolia Aérea/etiologia , Cervicalgia/tratamento farmacológico , Oxidantes Fotoquímicos/efeitos adversos , Ozônio/efeitos adversos , Acidente Vascular Cerebral/etiologia , Adulto , Doença Crônica , Embolia Aérea/diagnóstico por imagem , Terapia por Exercício , Humanos , Oxigenoterapia Hiperbárica , Injeções Intra-Arteriais , Imageamento por Ressonância Magnética , Masculino , Acidente Vascular Cerebral/diagnóstico por imagem , Artéria Vertebral
19.
Sci Total Environ ; 657: 340-350, 2019 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-30550899

RESUMO

We tested the independent and interactive effects of nitrogen (N; 0 and 80 kg ha-1), phosphorus (P; 0, 40 and 80 kg ha-1), and ozone (O3) application/exposure [ambient concentration (AA), 1.5 × AA and 2.0 × AA] for five consecutive months on biochemical traits of the O3-sensitive Oxford poplar clone. Plants exposed to O3 showed visible injury and an alteration of membrane integrity, as confirmed by the malondialdehyde by-product accumulation (+3 and +17% under 1.5 × AA and 2.0 × AA conditions, in comparison to AA). This was probably due to O3-induced oxidative damage, as documented by the production of superoxide anion radical (O2-, +27 and +63%, respectively). Ozone per se, independently from the concentrations, induced multiple signals (e.g., alteration of cellular redox state, increase of abscisic acid/indole-3-acetic acid ratio and reduction of proline content) that might be part of premature leaf senescence processes. By contrast, nutrient fertilization (both N and P) reduced reactive oxygen species accumulation (as confirmed by the decreased O2- and hydrogen peroxide content), resulting in enhanced membrane stability. This was probably due to the simultaneous involvement of antioxidant compounds (e.g., carotenoids, ascorbate and glutathione) and osmoprotectants (e.g., proline) that regulate the detoxification processes of coping with oxidative stress by reducing the O3 sensitivity of Oxford clone. These mitigation effects were effective only under AA and 1.5 × AA conditions. Nitrogen and P supply activated a free radical scavenging system that was not able to delay leaf senescence and mitigate the adverse effects of a general peroxidation due to the highest O3 concentrations.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Antioxidantes/metabolismo , Fertilizantes , Nitrogênio/metabolismo , Ozônio/efeitos adversos , Fósforo/metabolismo , Populus/fisiologia , Relação Dose-Resposta a Droga , Nutrientes/administração & dosagem , Nutrientes/metabolismo , Populus/genética
20.
J Plant Res ; 131(6): 915-924, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30426334

RESUMO

Ozone (O3) pollution and the availability of nitrogen (N) and phosphorus (P) in the soil both affect plant photosynthesis and chlorophyll (Chl) content, but the interaction of O3 and nutrition is unclear. We postulated that the nutritional condition changes plant photosynthetic responses to O3. An O3-sensitive poplar clone (Oxford) was subject to two N levels (N0, 0 kg N ha- 1; N80, 80 kg N ha- 1), two P levels (P0, 0 kg P ha- 1; P80, 80 kg P ha- 1) and three levels of O3 exposure (ambient concentration, AA; 1.5 × AA; 2.0 × AA) over a growing season in an O3 free air controlled exposure (FACE) facility. The daily change of leaf gas exchange and dark respiration (Rd) were investigated at mid-summer (August). Chl a fluorescence was measured three times in July, August and September. At the end of the growing season, Chl content was measured. It was found that Chl content, the maximum quantum yield (Fv/Fm), Chl a fluorescence performance index (PI) and gas exchange were negatively affected by elevated O3. Phosphorus may mitigate the O3-induced reduction of the ratio of photosynthesis to stomatal conductance, while it exacerbated the O3-induced loss of Fv/Fm. Nitrogen alleviated negative effects of O3 on Fv/Fm and PI in July. Ozone-induced loss of net photosynthetic rate was mitigated by N in medium O3 exposure (1.5 × AA). However, such a mitigation effect was not observed in the higher O3 level (2.0 × AA). Nitrogen addition exacerbated O3-induced increase of Rd suggesting an increased respiratory carbon loss in the presence of O3 and N. This may result in a further reduction of the net carbon gain for poplars exposed to O3.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Nitrogênio/metabolismo , Ozônio/efeitos adversos , Fósforo/metabolismo , Fotossíntese/efeitos dos fármacos , Populus/metabolismo , Clorofila/metabolismo , Relação Dose-Resposta a Droga , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Populus/efeitos dos fármacos , Populus/fisiologia
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