Elevated Ozone Concentrations Research Articles

Aging of secondary organic aerosol generated from the ozonolysis of α-pinene: effects of ozone, light and temperature

Abstract. A series of experiments was conducted in the CESAM (French acronym for Experimental Multiphasic Atmospheric Simulation Chamber) simulation chamber to investigate the evolution of the physical and chemical properties of secondary organic aerosols (SOAs) during different forcings. The present experiments represent a first attempt to comprehensively investigate the influence of oxidative processing, photochemistry, and diurnal temperature cycling upon SOA properties. SOAs generated from the ozonolysis of α-pinene were exposed under dry conditions (< 1% relative humidity) to (1) elevated ozone concentrations, (2) light (under controlled temperature conditions) or (3) light and heat (6 °C light-induced temperature increase), and the resultant changes in SOA optical properties (i.e. absorption and scattering), hygroscopicity and chemical composition were measured using a suite of instrumentation interfaced to the CESAM chamber. The complex refractive index (CRI) was derived from integrated nephelometer measurements of 525 nm wavelength, using Mie scattering calculations and measured number size distributions. The particle size growth factor (GF) was measured with a hygroscopic tandem differential mobility analyzer (H-TDMA). An aerosol mass spectrometer (AMS) was used for the determination of the f44 / f43 and O : C ratio of the particles bulk. No change in SOA size or chemical composition was observed during O3 and light exposure at constant temperature; in addition, GF and CRI of the SOA remained constant with forcing. On the contrary, illumination of SOAs in the absence of temperature control led to an increase in the real part of the CRI from 1.35 (±0.03) to 1.49 (±0.03), an increase of the GF from 1.04 (±0.02) to 1.14 (±0.02) and an increase of the f44 / f43 ratio from 1.73 (±0.03) to 2.23 (±0.03). The simulation of the experiments using the master chemical mechanism (MCM) and the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) shows that these changes resulted from the evaporation of semi-volatile and less oxidized SOA species induced by the relatively minor increases in temperature (~ 6 °C). These surprising results suggest that α-pinene–O3 SOA properties may be governed more by local temperature fluctuations than by oxidative processing and photochemistry.

Fungi in the future: interannual variation and effects of atmospheric change on arbuscular mycorrhizal fungal communities.

Understanding the natural dynamics of arbuscular mycorrhizal (AM) fungi and their response to global environmental change is essential for the prediction of future plant growth and ecosystem functions. We investigated the long-term temporal dynamics and effect of elevated atmospheric carbon dioxide (CO2) and ozone (O3) concentrations on AM fungal communities.Molecular methods were used to characterize the AM fungal communities of soybean (Glycine max) grown under elevated and ambient atmospheric concentrations of both CO2 and O3 within a free air concentration enrichment experiment in three growing seasons over 5 yr.Elevated CO2 altered the community composition of AM fungi, increasing the ratio of Glomeraceae to Gigasporaceae. By contrast, no effect of elevated O3 on AM fungal communities was detected. However, the greatest compositional differences detected were between years, suggesting that, at least in the short term, large-scale interannual temporal dynamics are stronger mediators than atmospheric CO2 concentrations of AM fungal communities.We conclude that, although atmospheric change may significantly alter AM fungal communities, this effect may be masked by the influences of natural changes and successional patterns through time. We suggest that changes in carbon availability are important determinants of the community dynamics of AM fungi.

UV-B辐射增强和O3浓度升高对大豆（Glycine max.）叶片内源激素和抗氧化能力的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 UV-B辐射增强和O3浓度升高对大豆叶片内源激素和抗氧化能力的影响 DOI: 10.5846/stxb201306081450 作者: 作者单位: 沈阳农业大学 农学院,沈阳农业大学 农学院,沈阳农业大学 农学院,沈阳农业大学 农学院,沈阳农业大学 农学院,沈阳农业大学 农学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(30970448);辽宁省高等学校优秀人才支持计划(LJQ2011072) Effects of plant endogenous hormones and antioxidant ability in soybean leaves under UV-B and ozone stress Author: Affiliation: College of agronomy,Shenyang Agricultural University,College of agronomy,Shenyang Agricultural University,College of agronomy,Shenyang Agricultural University,College of agronomy,Shenyang Agricultural University,College of agronomy,Shenyang Agricultural University,College of agronomy,Shenyang Agricultural University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:揭示大豆叶片内源激素对UV-B和臭氧胁迫的代谢机制和响应方式,为从分子水平研究植物内源激素对UV-B(Ultraviolet-B)和O3(Ozone)胁迫的适应机制奠定基础。以大豆(Glycine max.)为试验材料,利用开顶式气室研究UV-B(0.32 W/m2)和O3((110±10) nmol/mol)复合胁迫对大豆叶片内源激素含量及活性氧代谢系统的影响。结果表明:在大豆整个生育期内,与对照相比,UV-B胁迫使大豆叶片ABA(Abscisic acid)含量、ZR(Zeatin riboside)含量和IAA(Indoleacetic acid)含量显著降低,IAA/ABA、ZR/ABA、(IAA+ZR)/ABA比值升高,O2·(Superoxide anion free radical,O2·)产生速率和MDA(Malonaldehyde)含量升高,SOD(Superoxide dismutase)、CAT(Catalase)和POD(Peroxidase)活性显著降低;高浓度O3胁迫下,大豆叶片ABA和IAA含量显著下降、ZR含量显著增加,IAA/ABA、ZR/ABA、(IAA+ZR)/ABA值显著升高,O2·产生速率和MDA含量增加,SOD、CAT和POD活性显著降低;UV-B和O3复合胁迫下,大豆叶片ABA含量、ZR含量和IAA含量降低,ZR/ABA、(IAA+ZR)/ABA值下降,而IAA/ABA值升高,O2·产生速率和MDA含量显著增加,SOD、CAT和POD活性显著降低。UV-B辐射增强和O3浓度升高单一及复合作用使大豆叶片内源激素间平衡改变,进而影响大豆叶片的代谢水平。持续胁迫下,植株抗氧化能力下降,对大豆表现为伤害效应。UV-B和O3复合胁迫比单独胁迫时的影响有所加深,但是小于两者单独作用时影响的简单累加。 Abstract:Widespread areas of crop production are presently at risk for damage from ambient atmospheric ozone (O3) concentrations and ultraviolet-B radiation (UV-B). The concentration of tropospheric ozone and UV-B have been rising due to aggravating urbanization since the Industrial Revolution, which has had a significant impact on plants and plants play an important role in adjusting structure and function of the ecosystem. Thus, to correctly evaluate how elevated O3 concentration and UV-B radiation affect plants is of great significance. The effects of O3 and UV-B on plant growth and some physiological indexes such as photosynthesis have been reported separately for a number of species by controlled experiments,but only few experiments have focused on their interaction. It is not distinct on interaction mechanism between O3 and UV-B. Especially, it is lack of reports to investigate the effects on endogenous hormone of a single species exposed to UV-B and O3 under well-controlled experimental conditions.Open-top chambers were utilized to investigate endogenous hormones content, change of lipid peroxidation extent, ROS (Reactive oxygen species, ROS) production rate, anti-oxidation enzymes activities in soybean leaves under elevated ozone concentration (110±10 nmol/mol) and UV-B radiation (0.32 W/m2) singly and in combination treatment. The results indicated that enhanced UV-B radiation induced a decrease on abscisic acid (ABA) content, indoleacetic acid (IAA) content, zeatin riboside (ZR) content, the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and a increase on ratio of IAA/ABA, ZR/ABA, (IAA+ZR)/ABA, superoxide anion free radical (O2·) production rate, Malondialdehyde (MDA) content, in soybean leaves during the whole growth stage and the ratio of IAA/ABA, ZR/ABA, (IAA+ZR)/ABA showed significantly increase at flowering stage,but slightly decrease at podding stage. Elevated O3 concentration exposure showed the similar effects, which resulted in lower ABA content, IAA content, the activities of SOD, CAT, POD and higher ZR content, O2· production rate, MDA content, ratio of IAA/ABA, ZR/ABA, (IAA+ZR)/ABA compared with the control and the ratio of IAA/ABA, ZR/ABA, (IAA+ZR)/ABA showed significantly increase at branching stage and flowering stage. A increase of ZR content may improve the antioxidant ability of soybean. UV-B radiation and O3 concentration combined stress induced a decrease on ABA content, IAA content, ZR content, the activities of SOD, CAT, POD, ratio of ZR/ABA, (IAA+ZR)/ABA and a increase on IAA/ABA ratio, O2· production rate, MDA content. The ratio of ZR/ABA showed significantly decrease at flowering stage and podding stage, but the difference of the ratio of IAA/ABA and (IAA+ZR)/ABA is not significant at the whole growth stage. The antagonism effect appears between ABA and ZR under enhanced UV-B and O3 in combination. Obviously, enhanced UV-B radiation and elevated O3 concentration caused significant variation on endogenous hormone balance and accelerated ROS metabolism rates and reduced anti-oxidative enzymes activities in soybean leaves. Compared with UV-B and O3 singly, UV-B and O3 in combination caused significant decrease in soybean endogenous hormone content and antioxidant ability. UV-B and O3 in combination enhanced the negative effect on soybean compared with UV-B and O3 alone but less than the simple accumulation effects of UV-B and O3 alone. 参考文献 相似文献 引证文献

Impact of Ozone on Sequestration of Carbon by Swedish Forests under a Changing Climate: A Modeling Study

The annual growth rates in Swedish forests are higher than the annual harvest rates, and this has resulted in high rates of carbon sequestration in the Swedish forestry sector. Any factor that tends to reduce growth rates also has the potential to reduce forest carbon sequestration rates, and ozone may be one such factor. The aim of this study was to estimate to what extent the occurrence of elevated tropospheric ozone concentrations can negatively affect carbon sequestration by Swedish forest ecosystems. The net primary production (NPP) of Swedish forests was simulated, using the 3-PG model, for representative forest stands in six different geographical zones across Sweden, with and without assumed negative impacts of ozone. Ozone impacts were derived from dose-response relationships, calculated from open-top chamber experiments with young trees. The results of the 3-PG simulations showed that the NPP was generally higher in the A2 and B2 Intergovernmental Panel on Climate Change (IPCC) future climate scenarios, as compared to the current climate, for all tree species and in all geographical zones across Sweden. Biomass production was reduced by 4.3‐15.5% for conifers (Norway spruce (Picea abies L) and Scots pine (Pinus sylvestris L) and by 1.4‐4.3% for birch (Betula pendula Roth and Betula pubescence Ehrh) under ambient ozone conditions as compared to the preindustrial ozone level. The greatest reduction in biomass was found in southern Sweden. Biomass was reduced by similar percentage value in future climate scenarios as that in the current climate.

Impact of Elevated Ozone on Growth, Yield and Nutritional Quality of Two Wheat Species in Northern India

Sensitivity to tropospheric ozone is highly variable in cultivars of different plant species. Wheat, an important cereal crop, has been found to be sensitive to elevated ozone levels leading to differences in grain yields. The objective of this study was to compare the effects of elevated tropospheric ozone on growth, yield and nutritional quality of two species of wheat, Triticum aestivum (PBW 343) and Triticum durum (HD 2936), which are tropical wheat cultivars commonly grown in northern India. Experiments were conducted growing winter wheat (rabi season) under elevated tropospheric ozone in northern India for two years in open-top chambers (OTCs) under charcoal-filtered air (CF), non-filtered air (NF), open air (OA) and elevated ozone (EO) concentration (NF + 25-35 ppb O3). There were different species responses to EO, with the modern aestivum wheat cultivar being more sensitive than durum wheat. The declines in all growth and yield parameters were greater in T. aestivum than T. durum in both the years. On average there was a 7% greater reduction in the photosynthetic rate and stomatal conductance in T. aestivum as compared to T. durum under EO at the flowering stage, and a 6% more reduction in leaf chlorophyll was observed on T. aestivum as compared to T. durum. Exposure to elevated O3 caused a decrease in the number of leaves and leaf area index, rubisco enzyme activity and chlorophyll in both the species. More reductions in grain yield were observed in T. aestivum (15 and 19%) as compared to T. durum (9 and 13%) under EO in the two years, respectively. Filtration of air significantly increased all growth and yield parameters in both species of wheat.

Effects of elevated ozone concentration on CH4 and N2O emission from paddy soil under fully open-air field conditions.

We investigated the effects of elevated ozone concentration (E-O3) on CH4 and N2O emission from paddies with two rice cultivars: an inbred Indica cultivar Yangdao 6 (YD6) and a hybrid one II-you 084 (IIY084), under fully open-air field conditions in China. A mean 26.7% enhancement of ozone concentration above the ambient level (A-O3) significantly reduced CH4 emission at tillering and flowering stages leading to a reduction of seasonal integral CH4 emission by 29.6% on average across the two cultivars. The reduced CH4 emission is associated with O3-induced reduction in the whole-plant biomass (-13.2%), root biomass (-34.7%), and maximum tiller number (-10.3%), all of which curbed the carbon supply for belowground CH4 production and its release from submerged soil to atmosphere. Although no significant difference was detected between the cultivars in the CH4 emission response to E-O3, a larger decrease in CH4 emission with IIY084 (-33.2%) than that with YD6 (-7.0%) was observed at tillering stage, which may be due to the larger reduction in tiller number in IIY084 by E-O3. Additionally, E-O3 reduced seasonal mean NOx flux by 5.7% and 11.8% with IIY084 and YD6, respectively, but the effects were not significant statistically. We found that the relative response of CH4 emission to E-O3 was not significantly different from those reported in open-top chamber experiments. This study has thus confirmed that increasing ozone concentration would mitigate the global warming potential of CH4 and suggested consideration of the feedback mechanism between ozone and its precursor emission into the projection of future ozone effects on terrestrial ecosystem.

Association of short-term exposure to ground-level ozone and respiratory outpatient clinic visits in a rural location – Sublette County, Wyoming, 2008–2011

ObjectiveShort-term exposure to ground-level ozone has been linked to adverse respiratory and other health effects; previous studies typically have focused on summer ground-level ozone in urban areas. During 2008–2011, Sublette County, Wyoming (population: ~10,000 persons), experienced periods of elevated ground-level ozone concentrations during the winter. This study sought to evaluate the association of daily ground-level ozone concentrations and health clinic visits for respiratory disease in this rural county. MethodsClinic visits for respiratory disease were ascertained from electronic billing records of the two clinics in Sublette County for January 1, 2008–December 31, 2011. A time-stratified case-crossover design, adjusted for temperature and humidity, was used to investigate associations between ground-level ozone concentrations measured at one station and clinic visits for a respiratory health concern by using an unconstrained distributed lag of 0–3 days and single-day lags of 0 day, 1 day, 2 days, and 3 days. ResultsThe data set included 12,742 case-days and 43,285 selected control-days. The mean ground-level ozone observed was 47±8ppb. The unconstrained distributed lag of 0–3 days was consistent with a null association (adjusted odds ratio [aOR]: 1.001; 95% confidence interval [CI]: 0.990–1.012); results for lags 0, 2, and 3 days were consistent with the null. However, the results for lag 1 were indicative of a positive association; for every 10-ppb increase in the 8-h maximum average ground-level ozone, a 3.0% increase in respiratory clinic visits the following day was observed (aOR: 1.031; 95% CI: 0.994–1.069). Season modified the adverse respiratory effects: ground-level ozone was significantly associated with respiratory clinic visits during the winter months. The patterns of results from all sensitivity analyzes were consistent with the a priori model. ConclusionsThe results demonstrate an association of increasing ground-level ozone with an increase in clinic visits for adverse respiratory-related effects in the following day (lag day 1) in Sublette County; the magnitude was strongest during the winter months; this association during the winter months in a rural location warrants further investigation.

The roles of deep convection and extratropical mixing in the tropical tropopause layer: An in situ measurement perspective

AbstractThe majority of air which enters the stratosphere passes through the tropical tropopause layer (TTL), where the temperature profile and amount of deep convection set the entry level for stratospheric water vapor. We use simultaneous in situ measurements of ozone, carbon monoxide, carbon dioxide, water vapor, and heavy water vapor (HDO) from the 2006 Costa Rica Aura Validation Experiment and 2007 Tropical Composition, Cloud, and Climate Coupling campaigns in a one‐dimensional mixing model to investigate how different transport pathways in the TTL impact the amount of water vapor which enters the stratosphere. We focused on four main pathways: (1) slow upward ascent, (2) isentropic transport from the midlatitude lowermost stratosphere, (3) convective injection, and (4) descent within the TTL coupled to convection. Each pathway brings air into the TTL with a specific chemical signature, such that anomalies in simultaneously measured tracer concentrations can be used to identify the source of the air mass. We found that isentropic transport from the midlatitude lowermost stratosphere accounted for 20–60% of the air in the lower TTL and 20–40% of air above the tropopause, bringing elevated ozone concentrations which radiatively warm the TTL, impacting the amount of dehydration which takes place. Convective input accounted for on average ~30% of the air measured below 370 K potential temperature, and ~10% of air above the tropopause in both summer and winter, increasing water vapor concentrations above the tropopause by 0.3 ppmv on average and by up to 1.6 ppmv in some air masses.

Phenolic compounds and antioxidant ability responses to experimental free-air ozone exposure in two wheat cultivars.

Effects of elevated ozone concentrations [O3] on two wheat (Triticum aestivum L.) cultivars [Yangmai16 (Y16) and Yannong19 (Y19)] were investigated to determine the different metabolic mechanisms of phenolic compounds under O3-FACE (free-air controlled enrichment) condition. This study specifically investigated changes of phenolic compounds content, secondary metabolism related enzymes activities, lipid peroxidation extent and reactive oxygen species (ROS) content in the leaves of two wheat cultivars. Results indicated that elevated [O3] (1.5 × ambient [O3]) induced different regulation mechanisms of secondary metabolism in different wheat cultivars. Lipid peroxidation and ROS content increased under O3 stress, and these results were more pronounced in the leaves of Y19 than in those of Y16, suggesting that Y19 is more sensitive to O3 than Y16.

Herbivore-mediated material fluxes in a northern deciduous forest under elevated carbon dioxide and ozone concentrations.

Anthropogenic changes in atmospheric carbon dioxide (CO2 ) and ozone (O3 ) are known to alter tree physiology and growth, but the cascading effects on herbivore communities and herbivore-mediated nutrient cycling are poorly understood. We sampled herbivore frass, herbivore-mediated greenfall, and leaf-litter deposition in temperate forest stands under elevated CO2 (c. 560ppm) and O3 (c. 1.5× ambient), analyzed substrate chemical composition, and compared the quality and quantity of fluxes under multiple atmospheric treatments. Leaf-chewing herbivores fluxed 6.2gm(-2) yr(-1) of frass and greenfall from the canopy to the forest floor, with a carbon:nitrogen (C:N) ratio 32% lower than that of leaf litter. Herbivore fluxes of dry matter, C, condensed tannins, and N increased under elevated CO2 (35, 32, 63 and 39%, respectively), while fluxes of N decreased (18%) under elevated O3 . Herbivore-mediated dry matter inputs scaled across atmospheric treatments as a constant proportion of leaf-litter inputs. Increased fluxes under elevated CO2 were consistent with increased herbivore consumption and abundance, and with increased plant growth and soil respiration, previously reported for this experimental site. Results suggest that insect herbivory will reinforce other factors, such as photosynthetic rate and fine-root production, impacting C sequestration by forests in future environments.

Apoplastic antioxidant enzyme responses to chronic free-air ozone exposure in two different ozone-sensitive wheat cultivars

The effects of elevated ozone concentrations [O3] on two different ozone-sensitive wheat (Triticum aestivum L.) cultivars [Yangmai16 (Y16) and Yannong19 (Y19)] were investigated to determine the different apoplastic antioxidant mechanisms under O3-FACE (free-air controlled enrichment) condition. The results indicated that elevated [O3] (1.5 × ambient [O3]) induced increases in the production of superoxide anion (O2−), hydroxyl radical (HO), hydrogen peroxide (H2O2) and lipid peroxidation, and these results were more pronounced in the apoplasts of Y19 than in those of Y16. Apoplastic antioxidant enzymes were developmentally regulated and the effect of elevated [O3] depended on the developmental stage of wheat for both cultivars. In cultivar Y19, continuous O3 stress induced a decrease in the activity of apoplastic superoxide dismutase (SOD; EC 1.15.1.1), peroxidase (POD; EC 1.11.1.7) and ascorbate peroxidase (APX; EC 1.11.1.11) in the later growing stages, indicating Y19 appears to be the more sensitive cultivar and is prone to oxidative stress. The strategic response of antioxidant enzymes activities by Y16 in four different plant development stages (booting, flowering, filling and ripening) resulted in O3 stress-induced antioxidant defense responses, which indicated its higher tolerance to O3 stress. The same patterns of activity of apoplastic SOD and APX isozymes were observed in both Y16 and Y19 cultivars, while POD isozymes differed by cultivar in terms of the pattern of bands. The results of the present study show that O3 tolerance can be improved by regulating apoplastic ROS metabolism through the responses of apoplastic antioxidant enzymes to O3 stress in different plant development stages.

Analysis of a period of elevated ozone concentration reported over the Vaal Triangle on 2 June 2013

A peak in the ambient ozone concentration was observed at three of the six ambient air quality monitoring stations in the Vaal Triangle Airshed Priority Area on the second of June 2013. The ozone peak was associated with elevated concentrations of particulate matter, including PM10, PM2.5 and black carbon, but not sulphur dioxide, oxides of nitrogen, carbon monoxide nor benzene. Back trajectory analysis using Hysplit showed that the air masses containing the high levels of ozone passed over areas influenced by coal fired power stations in the Waterberg, metal processing in the Bojanala region and high intensity fires 30km to 50km upwind of the stations.

North American terrestrial CO2 uptake largely offset by CH4 and N2O emissions: toward a full accounting of the greenhouse gas budget.

The terrestrial ecosystems of North America have been identified as a sink of atmospheric CO2 though there is no consensus on the magnitude. However, the emissions of non-CO2 greenhouse gases (CH4 and N2O) may offset or even overturn the climate cooling effect induced by the CO2 sink. Using a coupled biogeochemical model, in this study, we have estimated the combined global warming potentials (GWP) of CO2, CH4 and N2O fluxes in North American terrestrial ecosystems and quantified the relative contributions of environmental factors to the GWP changes during 1979–2010. The uncertainty range for contemporary global warming potential has been quantified by synthesizing the existing estimates from inventory, forward modeling, and inverse modeling approaches. Our “best estimate” of net GWP for CO2, CH4 and N2O fluxes was −0.50 ± 0.27 Pg CO2 eq/year (1 Pg = 1015 g) in North American terrestrial ecosystems during 2001–2010. The emissions of CH4 and N2O from terrestrial ecosystems had offset about two thirds (73 %±14 %) of the land CO2 sink in the North American continent, showing large differences across the three countries, with offset ratios of 57 % ± 8 % in US, 83 % ± 17 % in Canada and 329 % ± 119 % in Mexico. Climate change and elevated tropospheric ozone concentration have contributed the most to GWP increase, while elevated atmospheric CO2 concentration have contributed the most to GWP reduction. Extreme drought events over certain periods could result in a positive GWP. By integrating the existing estimates, we have found a wide range of uncertainty for the combined GWP. From both climate change science and policy perspectives, it is necessary to integrate ground and satellite observations with models for a more accurate accounting of these three greenhouse gases in North America.Electronic supplementary materialThe online version of this article (doi:10.1007/s10584-014-1072-9) contains supplementary material, which is available to authorized users.

高浓度O3及太阳辐射减弱对冬小麦PSⅡ光合活性及光能耗散的影响

为给地表太阳辐射减弱和O₃浓度增加等大气环境变化条件下我国粮食生产和安全提供安全评估依据，利用开顶式气室（OTC）和黑色遮光网开展了1种熏气水平和2种辐射减弱程度的大田试验（野外CK，T1：遮光20%，T2：遮光40%，T3：O₃浓度100 nL/L，T4：O₃浓度100 nL/L与遮光20%复合，T5：O₃浓度100 nL/L与遮光40%复合）。结果表明：T1、T2和T4组的<em>Fv/Fm</em>、<em>L</em>_（PFD）与CK均相似且变化不明显，Yield、<em>qP</em>、<em>Y</em>（<em>NO</em>）、（1-<em>qP</em>）/<em>NPQ</em>分别较CK不同程度下降，而<em>NPQ</em>和<em>Y</em>（<em>NPQ</em>）较CK分别较大程度升高；T3-T5组的<em>Fv/Fm</em>，<em>L</em>_（PFD） 、Yield、<em>qP</em>、<em>Y</em>（<em>NO</em>）和（1-<em>qP</em>）/<em>NPQ</em>较CK不同程度降低，而<em>NPQ</em>和<em>Y</em>（<em>NPQ</em>）较CK分别显著升高且T5增幅显著大于T1-T4组。综上表明，复合胁迫下，冬小麦光能更多地向调节性热耗散途径分配，辐射减弱效应能使臭氧胁迫下冬小麦较好地自我调节以更好地适应逆境环境。尽管冬小麦对复合胁迫具有一定的适应能力，地表臭氧浓度升高和辐射减弱仍然是我国粮食生产中面临的一个重要问题。;At present, the aerosol radiative effect is the focus of many scholars and the solar radiation attenuated by direct or indirect effect to cause crop photosynthetic capacity decreased, resulting in crop production; At the same time the surface concentration of O₃ continuously increased, O₃ has strong negative effect on crop growth and metabolic processes and O₃ was direct threat to food safety to crops. Providing the basis for the security of National grain assessments and production under the conditions of reduced solar irradiance and elevated ozone concentration and other changes in atmospheric. Used open-top chamber (OTC) and black shading network to launch a fumigation level and two kinds of irradiance reduction degree. (field: CK, T1: shading 20%, T2: shading 40%, T3: 100nL/L O₃ concentration, T4: 100nL/L O₃ concentration and shading 20% compound, T5: 100nL/L O₃ concentration and shading 40% compound). The results showed that contrasting to CK, the <em>Fv/Fm</em>(PSⅡ maximum quantum yield), <em>L</em>_(PFD) (the relative limit of Photosynthetic function) of T1 treatment are similar and had no obvious changes, but the Yield, <em>qP</em>(Photochemical quenching coefficient), <em>Y(NO)</em> (the non regulation of energy dissipation in quantum yield), (1-<em>qP</em>)/<em>NPQ</em>(Light quantum excess degree) are decreased by 1.3%-21.5%, 7.5%-21.2%, 14.8%-20.6%, 27.7%-51.4% and NPQ(non photochemical quenching coefficient), <em>Y (NPQ)</em>(regulation of energy dissipation in quantum yield) are increased by 12.0%-31.9%, 53.4%-116%. Fv/Fm of T2 treatment had no significant changes, The Yield, <em>qP</em>, <em>L</em>_(PFD), <em>Y(NO)</em>, (1-<em>qP</em>)/<em>NPQ</em> were decreased by 13.2%-34.0%, 16.9%-36.2%, 6.8%-8.3%, 2.8%-16.0%, 23.1%-32.7%, The <em>NPQ</em>, <em>Y(NPQ)</em> were increased downby 15.9%-38.2% 39.5%-65.4%. The <em>Fv/Fm</em>, Yield(Optical system II actual photochemical efficiency), <em>qP</em> of T3 treatment were decreased by 11.8%-12.6%, 19.1%-28.0%, 15.6%-43.1%. The <em>L</em>_(PFD), <em>NPQ</em>, <em>Y</em>(<em>NPQ</em>), <em>Y</em>(<em>NO</em>), (1-<em>qP</em>)/<em>NPQ</em> increased by 1.1%-7.2%, 20.8%-83.6%, 12.6%-40.3%, 3.9%-22.2% obviously, 0.6%-34.1%. <em>Fv/Fm</em>, <em>L</em>_(PFD) of T4 treatment were similar to CK and compared with CK, the Yield, <em>qP</em>, <em>Y(NO)</em>, (1-<em>qP</em>)/<em>NPQ</em> decreased by 12.7%-42.8%, 7.2%-14.4% 18.8%-27.5%, 16.4%-45.1% and <em>NPQ, Y(NPQ)</em> increased by 13.4%-45.2% 6.9%-110.8%. <em>Fv/Fm</em>, Yield, <em>qP</em>, <em>L</em>_(PFD), </em>Y(NO)</em>, (1-<em>qP</em>)/<em>NPQ</em> of T5 treatment compared with CK, decreased by 30.4%-50.9%, 27.7%-43.2%, 2.2%-4.9%, 2.2%-10.2%, 23.3%-26.2%, 47.1%-61.6% and <em>NPQ</em>, <em>Y(NPQ)</em> increased by 27.5%-51.6% 63.3%-142.7%. Those results showed that (1) the single factor of Ozone significantly changed photosynthetic activity and distribution of light energy of winter wheat leaves but the single factor of reduced solar radiation alleviated negative effect photosynthesis restriction of winter wheat to a certain extent. (2) Further, under the combined stress, the light energy of winter wheat distributed more to regulatory heat dissipation. Composite action enhanced obviously the heat dissipation capability of winter wheat Radiation attenuation effect could cause winter wheat at the ozone stress self-regulated to better adapt to the adverse environment. Reducing appropriate the amount of solar radiation under Ozone stress could alleviate and reduce the light injury of winter wheat leaves. (3) Reducing solar radiation under the Ozone stress could inhibition the light injury and ensure the winter wheat optical system function normally and the normal growth of Winter Wheat. (4) In spite of winter wheat on composite stress has a certain ability to adapt; the reduced solar irradiance and elevated ozone concentration are still an important issue facing national grain production.

The protective role of antioxidants in the defence against ROS/RNS-mediated environmental pollution.

Overproduction of reactive oxygen and nitrogen species can result from exposure to environmental pollutants, such as ionising and nonionising radiation, ultraviolet radiation, elevated concentrations of ozone, nitrogen oxides, sulphur dioxide, cigarette smoke, asbestos, particulate matter, pesticides, dioxins and furans, polycyclic aromatic hydrocarbons, and many other compounds present in the environment. It appears that increased oxidative/nitrosative stress is often neglected mechanism by which environmental pollutants affect human health. Oxidation of and oxidative damage to cellular components and biomolecules have been suggested to be involved in the aetiology of several chronic diseases, including cancer, cardiovascular disease, cataracts, age-related macular degeneration, and aging. Several studies have demonstrated that the human body can alleviate oxidative stress using exogenous antioxidants. However, not all dietary antioxidant supplements display protective effects, for example, β-carotene for lung cancer prevention in smokers or tocopherols for photooxidative stress. In this review, we explore the increases in oxidative stress caused by exposure to environmental pollutants and the protective effects of antioxidants.

Effects of Elevated Ozone Concentration on Starch and Starch Synthesis Enzymes of Yangmai 16 Under Fully Open-Air Field Conditions

O3 is not only greenhouse gas but also a primary gaseous contaminant in the atmosphere. It has long-lasting effects on crop growth, yield and quality, and brings a series of ecological and environmental problems. A free-air controlled enrichment (FACE) system was applied to study the effect of elevated ozone concentration on activities of key enzymes of starch synthesis of Yangmai 16 in 2009-2010. The main-plot treatment had two levels of O3: ambient level (A-O3) and 50% higher than ambient level (E-O3). The main results were that accumulation rate of amylose, amylopectin and starch were represented in a single peak curve, and their content and accumulation amount rose gradually. The O3 elevation decreased the accumulation rate of amylose, amylopectin and starch amylase, reduced the accumulation amount of amylopectin and starch, and decreased the content of amylopectin and starch, but increased the content of amylose. With the increase of O3 concentration, the enzyme activity of grain granule-bound starch synthase (GBSS), soluble starch synthase (SSS) and starch branching enzyme (SBE) decreased after anthesis. The activities of GBSS and SSS had highly significant correlations with amylose, amylopectin and starch accumulation rate, and the activity of SBE had significant correlations with these items. So the O3 elevation decreased the activity of key enzymes of starch synthesis, which led to the variation of starch synthesis.

Effects of chronic elevated ozone concentration on the redox state and fruit yield of red pepper plant Capsicum baccatum

Ozone (O3) is one of the most harmful air pollutants to crops, contributing to high losses on crop yield. Tropospheric O3 background concentrations have increased since pre-industrial times reaching phytotoxic concentrations in many world regions. Capsicum peppers are the second most traded spice in the world, but few studies concerning the O3 effects in this genus are known. Thereby, the aim of this work was to evaluate the effects of chronic exposure to elevated O3 concentrations in red pepper plant Capsicum baccatum L. var. pendulum with especial considerations on the leaf redox state and fruit yield. Fifteen C. baccatum plants were exposed to O3 in open-top chambers during fruit ripening (62 days) at a mean concentration of 171.6µg/m3 from 10:00am to 4:00pm. We found that O3 treated plants significantly decreased the amount and the total weight of fruits, which were probably a consequence of the changes on leaf oxidative status induced by ozone exposure. Ozone exposed plants increased the reactive oxygen species (ROS) levels on the leaves, which may be associated with the observed decrease on the activity of enzymatic antioxidant defense system, as well with lower levels of polyphenol and reduced thiol groups. Enhanced ROS production and the direct O3 reaction lead to biomacromolecules damages as seen in the diminished chlorophyll content and in the elevated lipid peroxidation and protein carbonylation levels. Through a correlation analysis it was possible to observe that polyphenols content was more important to protect pepper plants against oxidative damages to lipids than to proteins.

Impact of free air ozone concentration enrichment on cooked rice (Wuyunjing 21) texture and palatability

研究表明不断升高的地表臭氧浓度使作物生长受抑、产量下降, 但对作物品质的影响则不太清楚, 特别是食味品质。本文于2009年和2010年在江苏省江都市小纪镇依托自由空气中臭氧浓度增高(free air ozone concentration enrichment, O₃-FACE)技术平台, 以本地主栽水稻品种"武运粳21"为供试材料, 设置大气背景臭氧浓度和高臭氧浓度(比大气背景臭氧浓度高50%)2个水平, 研究了地表臭氧浓度升高对粳稻物性和食味品质的影响。物性分析仪测定结果表明, 高浓度臭氧使熟米硬度平均增加13.6%, 达显著水平。食味计测定结果显示, 高浓度臭氧使稻米香气、光泽、味道、口感和综合值分别下降0.8%(<i>P</i>>0.1)、6.2%(<i>P</i><0.1)、2.6%(<i>P</i><0.1)、5.1%(<i>P</i><0.05)、4.3%(<i>P</i><0.05), 使完整性增加2.0%(<i>P</i><0.05)。不同年度间稻米物性和食味品质的差异较大, 但年度与臭氧间的交互作用未达显著水平。以上结果表明, 未来高浓度臭氧环境下生长的稻米蒸煮后将呈变硬趋势, 食味品质总体变劣。

Molecular and immunological characterization of ragweed (Ambrosia artemisiifolia L.) pollen after exposure of the plants to elevated ozone over a whole growing season.

Climate change and air pollution, including ozone is known to affect plants and might also influence the ragweed pollen, known to carry strong allergens. We compared the transcriptome of ragweed pollen produced under ambient and elevated ozone by 454-sequencing. An enzyme-linked immunosorbent assay (ELISA) was carried out for the major ragweed allergen Amb a 1. Pollen surface was examined by scanning electron microscopy and attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR), and phenolics were analysed by high-performance liquid chromatography. Elevated ozone had no influence on the pollen size, shape, surface structure or amount of phenolics. ATR-FTIR indicated increased pectin-like material in the exine. Transcriptomic analyses showed changes in expressed-sequence tags (ESTs), including allergens. However, ELISA indicated no significantly increased amounts of Amb a 1 under elevated ozone concentrations. The data highlight a direct influence of ozone on the exine components and transcript level of allergens. As the total protein amount of Amb a 1 was not altered, a direct correlation to an increased risk to human health could not be derived. Additional, the 454-sequencing contributes to the identification of stress-related transcripts in mature pollen that could be grouped into distinct gene ontology terms.

Evaluation of the Effect of Surface Ozone on Main Crops in East Asia: 2000, 2005, and 2020

In this paper, the possible effect of surface ozone on soybean, wheat, rice, and maize crops in East Asia in 2000, 2005, and 2020 is estimated. Spatial distribution and temporal variation of surface ozone concentrations are simulated using the Models-3 Community Multiscale Air Quality Modeling System coupled with the Regional Emission Inventory in Asia (CMAQ/REAS). The effect of surface ozone on main crops in East Asia is evaluated based on accumulated exposure over a threshold of 40 ppb (AOT40 index) during a period of 3 months of the growing season. We demonstrate some of the implications for policy-making in air quality management for East Asia by highlighting the effect of elevated surface ozone concentrations on harvest losses and the corresponding value of the main crops. These concentrations are calculated based on three scenarios of emission reduction policies in 2020: policy success case (PSC), reference case (REF), and policy failure case (PFC). Assuming no future changes in land use or cropping patterns from 2000 to 2020, we find that the highest relative yield (RY) losses are in wheat and soybean in East Asia. The RY losses for wheat are estimated to range between 17 and 35 % in 2000, 21 and 49 % in 2005, 18 and 36 % in 2020 (PSC), 20 and 46 % in 2020 (REF), and 22 and 62 % in 2020 (PFC); the corresponding values for rice are 6 and 12 %, 6 and 17 %, 6 and 15 %, 6 and 17 %, and 7 and 20 %; for soybean, they are 12 and 16 %, 19 and 25 %, 18 and 33 %, 21 and 40 %, and 25 and 49 %; and for maize, they are 3 and 4 %, 5.7 and 6 %, 6 and 9 %, 9 and 11 %, and 12 and 14 %. Quantitatively, the estimated losses in production of wheat in East Asia in 2000, 2005, and 2020 (PSC, REF, and PFC scenarios) are 32.4, 44.3, 42.2, 54.0, and 72.3 t, respectively; for rice, 34.9, 39.4, 42.4, 46.5, and 54.6 mmt; for soybean, 1.9, 3.3, 3.6, 4.9, and 7.0 mmt; and for maize, 3.6, 8.1, 11.4, 15.4, and 21.5 mmt. The estimated values of crop losses in East Asia in 2000, 2005, and 2020 (PSC, REF, and PFC scenarios) are as follows: 13.8, 17.4, 18.2, 21.3, and 26.7 billion Int. $. Therefore, adaptation measures in the PSC scenario in contrast to the PFC scenario could save around 8.5 billion Int. $ across East Asian countries in 2020.