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1.
Ribas  A.  Filella  I.  Gimeno  B. S.  Peñuelas  J. 《Water, air, and soil pollution》1998,107(1-4):347-365
A field study was conducted from May to October 1995 to assess ozone (O3) phytotoxicity in Catalonia (NE Spain) by determining a percentage value of leaf area injured by ozone on three tobacco cultivars, Bel-W3, Bel-C and Bel-B as bioindicators. Colorimetric parameters were also determined in an effort to have an objective assessment of ozone injury. The study was conducted simultaneously on eight sites where ozone levels and several meteorological parameters were continuosly monitored. Two sets of plants were used at each site. The first one was composed of six plants of each cultivar which were changed every two weeks while the second one involved two plants of each cultivar which were kept in the plots throughout the whole experimental period. Open Top Chambers were also used to test the response of the three cultivars to ozone under controlled conditions. The ozone levels correlated well with ozone injury on the Bel-W3 cultivar but not as well on the other two cultivars. The ozone levels did not fully account for all the observed injury. The response of tobacco plants to ozone concentrations and therefore its biomonitoring capacity depended also on different environmental conditions linked to stomatal behaviour such as temperature, humidity, wind or altitude. These environmental conditions had some effects on the intensity of Ozone injury. Ozone concentrations accumulated over a threshold of 60 ppb (AOT60) when VPD was below 1 KPa. Correlated well with the ozone injury and best explained the intensity tobacco injury symptoms. For large plants growing throughout the whole period of study, Bel-C was the best indicator cultivar for AOT60 over the 3 days prior to the last ozone injury assessment. The colorimetric parameters were indicators of seasonal changes but they were not good ozone damage indicators. It is concluded that tobacco cultivars were good bioindicators but meteorological and other environmental factors need to be considered in there use as biomonitors.  相似文献   

2.
Three bush bean cultivars (Lit, Groffy and Stella) were grown under four levels of ozone exposure (ambient air+50 ppb O3 ambient air+25 ppb O3, ambient air and charcoal filtered air) in open- top chambers. Number and leaf injury statistics showed significant reduction in the number of healthy leaves as the level of O3 increased. The area based leaf injury percentages of the cvs. Lit, Groffy and Stella were 69.8, 57.9 and 71.1% at the highest O3 level, 24.1, 19.6 and 30.3% at the 2nd highest O3 level, and 4.5, 0.7 and 5.6% at the ambient air, respectively. The plants grown in the filtered air revealed no injury symptoms. The stomatal conductances were found to decrease gradually in each cultivar as the O3 level increased. At the highest O3 level, Chlorophyll fluorescence measurements on the 2nd leaf from the top on 24th day of exposure resulted in significantly the highest Fv/Fm values, the lowest f0 and the highest Fm values whereas the 4th leaf showed the smallest Fm and correspondingly the smallest Fv/Fm values. This is an indication of photosystem II damage after accumulation of a high ozone dose in the 4th leaf. The photosynthetic rate of the 2nd leaf measured on 30th day of exposure was comparatively higher at the highest exposure but the data taken from the same leaf on 40th day of exposure showed significantly lower photosynthetic rate than the plants in ambient air. Both chlorophyll fluorescence and photosynthetic measurements indicated that ozone stressed leaves experience a stimulation of photosynthesis (possibly due to increased assimilate demand) prior to irreversible damage. Bush bean leaves need to accumulate a critical ozone dose(an AOT40 of presumably > 18 ppm-h) for reduction of the photosynthetic capacitys.  相似文献   

3.
In 1992 a cooperative project, Clover Sweden, was initiated. The aim was to study if subterranean clover could be used as a bioindicator in the different climate zones in Sweden by studying the impact of ambient ozone concentrations on this species in different parts of the country during three consecutive summer seasons. Plants of subterranean clover, Trifolium subterraneum, L., were exposed to ambient air at 24 sites from north to south Sweden. The project was designed to be compatible with the international programme, ICP Crops within the UNECE and the Convention on Long Range Transboundary Air Pollution. The results showed that subterranean clover is a useful bioindicator of ozone in all agricultural areas of Sweden, with the exception for very cool and rainy summers resulting in poor growth of the plants. In 1992, and especially in 1994, ozone injury was detected at almost all sites in Sweden, reflecting the higher ozone levels of those summers as compared to 1993, when ozone concentrations were generally low and not much injury was detected. Typical injury was chlorotic and bifacial necrotic lesions on parts of the leaf surface. It is concluded that at mean ozone concentrations of 25 ppb (24 h mean) and 30 ppb (7 h mean) there is a potential risk for injury on 10% of the leaves. When % injured leaves was plotted against AOT (Accumulated exposure Over a Threshold) using different thresholds, it became obvious that a threshold of 20 ppb ozone should be used in order to fully protect from leaf injury under Swedish conditions.  相似文献   

4.
During recent decades, ozone (O3) has gained much attention as a possible contributor to forest decline. Attempts have been made to set critical levels for O3 in order to protect vegetation. Damage to vegetation seems to depend on the pattern of exposure. Episodic peaks followed by periods with low concentrations are more phytotoxic than exposures with generally elevated concentrations but without peaks. The present experiment aims to examine whether O3 affects the wood production of beech seedlings. The seedlings were exposed to three different air pollution regimes: charcoal-filtered ambient air (CF), non-filtered ambient air (NF), and NF+30nl1?l?1 O3 8 hours day1 during summer periods (NFO). Basal stem diameter was measured regularly during three growing seasons. The relative diameter increase was significantly reduced with increased O3 concentration. AOT40 is calculated for all treatments and evaluated in relation to the relative diameter growth.  相似文献   

5.
This paper describes the results of a series of experiments designed to identify the relative importance of various factors which modify the responses of a sensitive species to ozone. The experiments were conducted in a closed chamber exposure system, enabling clover plants (Trifolium subterraneum L. cv Geraldton) to be exposed to ozone doses ranging from 0 to 1800 ppb.h, accumulated over 40 ppb (AOT40), for 7 h d?1, over 1 to 3 days. Microclimatic conditions during exposure ranged from 80 to 460 μmol m?2 s?1 photosynthetically active radiation (PAR), 26 to 61 percent relative humidity (%RJH) and 16 to 36 °C temperature. No clear dose response relationships were established for 1, 2 or 3 day exposures due to the influence of microclimatic and other factors during exposure. Artificial Neural Networks were used as a tool to identify patterns within the dose response data set and to clarify the effects of various microclimatic and dose topography responses, during multiple day exposures. Analysis of the trained neural network revealed that AOT40 on individual exposure days was the most important influences PAR on the first and third days of exposure, the mean relative humidity and the mean temperature for all days also had strong influences. Leaf age also had an influence but this was weaker. This paper describes these results in relation to the influences acting upon the plant and how these affect ozone uptake and resulting ozone injury.  相似文献   

6.
Exposure of Phaseolus vulgaris cv. Lit to ambient ozone caused a 14% pod yield reduction in 1994. This yield loss was assessed by comparing plants that were protected against ozone by treatment with EDU (ethylenediurea) with unprotected plants, both cultivated in pots with a continuous water supply. The plants had experienced an AOT40 of 8135 ppb.h during their growth. However, plant response to ozone depends on a large number of environmental and plant-specific conditions. Visible injury increased mainly after flowering and was much less severe on soil-grown bean cultivars (Lit, Stella and Groffy) not receiving additional water. Ozone fumigations in closed chambers before or after flowering proved that the growth stage during which the plants are exposed also plays a very important role with regard to injury development. Plants seem to be more susceptible during the generative growth stage and the relative cultivar sensitivity was related to the developmental stage during fumigation. However with regard to yield effects the timing of the ozone exposure seems to be less important.  相似文献   

7.
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8.
In recent decades, ambient gaseous pollution has increased due to anthropogenic activities worldwide. The studies to evaluate the adverse effects of ambient pollutants on commonly grown food crops are still limited, especially in Asian countries like Pakistan. The present study was conducted to measure the ambient pollutants in different sites of Faisalabad and their impact on growth and yield of wheat, mung bean and peas. Plants were grown in pots and placed at three sites named as control (Wire house of Government College University, Faisalabad), low pollution (LP) (Farm Area of Ayub Agricultural Research Institute) and high pollution (HP) (GT Chowk, Faisalabad) sites. Results showed that ambient ozone (O3) concentration was highest at HP site followed by LP site and was below AOT40 in control site. Ambient pollutants caused foliar injury in crops and decreased plant height, leaf area, biomass and grain yield. Pollutants caused a reduction in photosynthetic pigments, stomatal conductance and net photosynthetic rate and grain protein contents in all three crops. In conclusion, the ambient O3 level was highest at HP site, this current O3 level and other pollutants decreased the growth and yield of important food crops.  相似文献   

9.
We present here the effects of ambient ozone (O3)-induced decline in carbon availability, accelerated foliar senescence, and a decrease in aboveground biomass accumulation in the Aleppo pine (Pinus halepensis Mill.). Aleppo pine seedlings were continuously exposed in open-top chambers for 39 months to three different types of O3 treatments, which are as follows: charcoal-filtered air, nonfiltered air (NFA), and nonfiltered air supplemented with 40 ppb O3 (NFA+). Stable carbon isotope discrimination (??) and derived time-integrated c i/c a ratios were reduced after an accumulated ozone exposure over a threshold of 40 ppb (AOT40) value from April to September of around 20,000 ppb·h. An AOT40 of above 67,000 ppb·h induced reductions in ribulose-1,5-biphosphate carboxylase/oxygenase activity, aboveground C and needle N and K concentrations, the C/N ratio, Ca concentrations in twigs under 3 mm, and the aerial biomass, as well as increases in needle P concentrations and phosphoenolpyruvate carboxylase (PEPC) activity and the N and K concentrations in twigs under 3 mm. Macronutrients losses, the limitations placed on carbon uptake, and increases in catabolic processes may be the causes of carbon gain diminution in leaves which was reflected as a reduction in aboveground biomass at tree level. Stimulation of PEPC activity, the consequent decreased ??, and compensation processes in nutrient distribution may increase O3 tolerance and might be interpreted as part of Aleppo pine acclimation response to O3.  相似文献   

10.
Peña  R. M.  García  S.  Herrero  C.  Lucas  T. 《Water, air, and soil pollution》2000,117(1-4):289-303
Measurements of ozone were carried out at two different sites in the area surrounding a thermal power plant located in the Northwest of Spain during 1993–1995. The concentration of O3 in the ambient air varied from 6 to 257 μg m-3 exhibiting a wide temporal, seasonal and spatial variation. On a few occasions 1-hr ozone concentration was more than 180 μg m-3, which represents the maximum 1-hr limit of ozone in ambient air as prescribed by the European Commission.  相似文献   

11.
High ozone (O3) levels have been recorded in eastern Spain. A project was developed to identify the areas of elevated O3 and determine if these levels were above critical concentrations for plant damage. Thus, a network of bioindicators was established in two Autonomous Communities of Spain: Catalunya (31.930 km2) and Valencia (23.305 km2) to assess O3 phytotoxicity. Three tobacco cultivars, (Bel-W3, Bel-C and Bel-B) were used during the 1994 growing season in both Regions. In Catalunya the highest O3 phytotoxicity was recorded in coastal areas, while the phytotoxicity decreased as plants were grown further in-land. A lower O3 phytotoxicity was observed in coastal sites of the Valencia Autonomous Community, compared to Catalunya, although the O3 injury was observed downwind from Valencia city in the most resistant cultivar Bel-B. The results in the Valencian Community were difficult to interpret, since plant viruses were widely distributed, not only in indicator plants, but also in commercial crops grown in the area. The analysis of O3 concentrations, meteorological parameters and visible injury at the Catalan sites showed that high relative humidity levels could favour O3 phytotoxicity. Therefore, the interactions between O3 exposure and environmental conditions on plant response should be further studied for the establishment of sound critical levels.  相似文献   

12.
Plants represent one of the major sinks for tropospheric ozone that, at high concentrations, can affect plants' physiological activity with consequent serious damage. A research project has been promoted by the Lombardy Foundation for the Environment to investigate the effects of air pollution on forest ecosystems. The areas of study are located on the southern slopes of the Italian Alps in two valleys, only 10 km apart, selected because of their different plant injury: Val Gerola and Val Masino. Air quality (O3, NOx, SOx, VOC) and meteorological parameters were monitored during four summer seasons (1994-97) using automatic sampling devices providing hourly mean values for each variable. Data analysis showed very different ambient ozone concentrations at the two sites, with average concentration values observed in the more damaged valley (Val Gerola) twice those measured at the other site. Multivariate data analyses have been used to interpret the observed differences in long-term O3 exposure between the two sites and to identify possible underlying processes.  相似文献   

13.
The Landesumweltamt North-Rhine Westfalia is operating eight open-top chambers as well as six reference plots at a site on a westerly exposed slope (540 m a.s.) in the Egge mountains, 130 km northeast of the Ruhr area. Since 1991 eighteen 6 yr old beech trees (Fagus sylvatica L.) per plot/chamber were exposed either to ambient air (AA), non-filtered air (NF) or charcoal-filtered air. Ambient air pollutants (O3. SO2, NOx) as well as meteorological parameters were monitored continuously inside chambers as well as in the ambient. Growth parameters (bud development, stem diameter, shoot length, shoot diameter, leaf area, leaf colouration, leaf abscission) were assessed over the years 1992–1994.Even in the first year a marked earlier colouration of the leaves was observed in the NF (AOT 40=16.2 ppm·hr) versus the CF treatment (AOT 40=0.2 ppm·hr) and leaf abscission was two weeks earlier on NF-trees, indicating the common ozone effect of early senescence. Effects became more pronounced with increasing time of exposure. While hardly any effects on growth could be seen during the first and second year, shoot length and shoot diameter were reduced significantly by about 15 % in NF versus CF treatments in 1994. Similar effects were seen for the leaf area. No effects could be shown for bud development or stem diameter. Ozone specific symptoms were observed on individual trees in the NF and AA treatments and especially pronounced in 1994 (AOT 40=24.1 ppm·hr), but also to a much lesser extent in the CF-treatment. AOT40 value of 10 ppm·h, proposed as provisional standard for the protection of trees by UN-ECE seems to be stringent enough according to the results of this exposure study.  相似文献   

14.
This paper describes the use of dry free hanging filters, as passive samplers to determine ozone in the ambient air. The filters, with a diameter of 25?mm, were impregnated with 5,5??-disodium indigo disulphonate (IDS), a reagent for ozone. From the amount of reacted indigo compound, found on the filter, and the ozone concentration in the ambient air, a pseudo rate constant k 1, of the reaction between ozone (O3) and IDS on the filter, is calculated. The range of measurement is between 9 and 205???g/m3 ambient ozone. The dry filter method is specific for ozone, while the Dutch standard method NEN2789, based on an aqueous solution of IDS, has to be corrected for the presence of NO x . From wind tunnel and field experiments, k 1 proved to vary between 0.7 and 1.5?×?10?6?m3?s?1 (??g O3)?1 at wind velocities between 1 and 3?m/s and at an exposure time of 60?min. Within these conditions, ozone concentrations have been determined with free hanging filters in four busy streets in Yogyakarta, Indonesia and at two background sites using an average value of k 1 of 1.2?×?10?6. Subsequently, the traffic NO emission was estimated from the difference of the O3 concentrations at both sides of a road. For an arbitrary situation, an NO emission of 255???g/s per metre road length was calculated. The filter method is inexpensive and practical, needs no electricity, is easily assembled and can be used to perform measurements in remote areas. It is shown here that this simple measurement technique may support air quality studies, e.g., in developing countries.  相似文献   

15.
The experiments of the United Nations/Economic Commission for Europe (UN/ECE) International Cooperative Programme on effects of air pollution and other stresses on crops and non-wood plants (ICP-Crops) are designed to investigate the effects of ambient ozone pollution on crops and non-wood plants. Each year, participants from approximately 17 European countries conduct a series of coordinated experiments to determine which species develop visible injury following ozone episodes and whether the biomass or yield of sensitive species is reduced. In 1993, ozone injury was only seen at two thirds of sites but in 1994 injury was detected at almost all sites. This coincides with generally higher ozone concentrations measured in that year. Injury was seen on crops including subterranean clover (Trifolium subterraneum L.), white clover (Trifolium repens L.), bean (Phaseolus vulgaris L.), tomato (Lycopersicon esculentum), soybean (Glycine max), watermelon (Citrullus lanatus) and tobacco (Nicotiana tabacum L.) at experimental sites and in some cases, in commercial fields. The application of ethylenediurea (EDU) to some crop species reduced the level of visible injury. At some sites, the yield of EDU-treated bean plants was greater than that of untreated plants where the critical level of ozone for yield reduction was exceeded. Preliminary analysis of ozone concentrations in the days preceding injury indicated a sequential ozone concentration effect. The results are discussed in relation to Level I and Level II mapping of exceedance of the short- and long-term critical levels for ozone.  相似文献   

16.
Many natural vegetation species have been shown to be negatively affected by ozone. This study has investigated how the presence of competing species in a community affects two common responses to ozone: visible injury and senescence. Monocultures and mixtures of Trifolium repens and Lolium perenne were grown in large containers and were exposed in solardomes to either a rural episodic ozone profile (AOT40 of 12.86 ppm h) or control conditions (AOT40 of 0.02 ppm h) for 12 weeks. The proportion of ozone-injured or senesced leaves was different in the different regions of the canopy. The highest proportions of injured/senesced leaves were in the plant material growing at the edge of the canopy and the upper canopy, with a significantly lower proportion of injured leaves in the inner canopy. The presence of L. perenne increased the proportion of ozone-injured leaves in T. repens at the final harvest, whilst the presence of T. repens decreased the proportion of senesced leaves in L. perenne. In L. perenne, the proportion of injured leaves at the edge and inner canopy decreased significantly when grown in competition, whilst for T. repens the reverse effect occurred in the inner canopy only. Different mechanisms appeared to influence the interaction between response to ozone and competitors in these two species. In L. perenne the response to ozone may have been related to nitrogen supply, whereas in T. repens canopy structure was more important.  相似文献   

17.
Eight Nordic open‐top chamber experiments with field‐grown spring wheat were combined to obtain relationships between ozone exposure and yield loss. Two exposure indices, AOT30 and AOT40 (AOT = accumulated exposure over threshold), were tested. Strongly significant linear regressions between relative yield and exposure were obtained with both indices. The coefficient of determination (r2) was higher and the model assumptions of linear regression were satisfied to a larger extent with AOT30 than with AOT40. The exclusion of charcoal‐filtered treatments from the analysis made little difference to the regressions. The AOT30 regression model predicted larger yield loss than the AOT40 regression model, especially for the range of exposures, which is likely to occur in the Nordic countries. The protein content of the grain increased with increasing ozone exposure in all eight experiments, but to a varying degree.  相似文献   

18.
Field fumigation studies conducted in grassland, oak, aspen, and conifer, communities established the injury threshold of prevalent plant species to ozone. Several important species, including Bromus tectorum, Quercus gambelii, and Populus tremuloides, were injured by a single 2-hours exposure to 15 pphm ozone. Over half the perennial forbs and woody species studied were visibly injured at concentrations of 30 pphm ozone or less. It is postulated that lower concentrations at prolonged or repeated exposures to ozone may impair growth and affect community vigour and stability. Continued exposure of natural plant communities to ozone is expected to initiate major shifts in the plant composition of communities.  相似文献   

19.
An experimental study was performed in open-top chambers to assess the relative O3-sensitivity of the following Mediterranean woody plants: Quercus ilex ssp. ilex, Quercus ilex ssp. ballota, Olea europaea ssp. sylvestris, Ceratonia siliqua and Arbutus unedo. Assessment of O3 ‘sensitivity’ was based on the development of O3-induced visible injury and the extent of the reduction in relative growth rate induced by O3. Two-year-old seedlings were exposed in open-top chambers to charcoal filtered air (CFA), Non-filtered air (NFA) or Non-filtered air supplied with 40 ppb O3 from 09:00 to 18:00 hours (NFA+40). No clear relationships were found between the development of visible injury and effects on plant growth or accumulated biomass. Olea europea ssp. sylvestris and Quercus ilex ssp. ballota appeared to be the most O3-sensitive tree species screened; a ten month exposure to ambient O3 levels (AOT40 = 12.4 ppm.h) caused reductions in height and/or stem growth. Further research is needed to characterise the physiological, biochemical and anatomical characteristics that may underlie the ‘sensitivity’ of certain Mediterranean species to O3  相似文献   

20.
Fagnano  M.  Merola  G.  Forlani  A.  Postiglione  L.  Fuhrer  J. 《Water, air, and soil pollution》2004,155(1-4):383-398
Yield losses from ozone pollution can be estimated by two methods: one involves the use of sensitive (S) and resistant (R) biotypes of white clover (Trifolium repens L., cv. Regal) exposed in ambient air, the other is based on the use of open-top chambers (OTC) supplied either with charcoal-filtered (CF) or non-filtered (NF) air. In southern Italy the two methods have been compared using the clover biotypes. The aim was (1) to compare the extent of ozone-induced yield reductions estimated by the two methods, (2) to evaluate the effect of the chamber enclosure on the growth of both biotypes, and (3) to compare plant water consumption in the different environments. On the average, the yield reduction was 23% when derived from the S/R yield ratio in ambient air, and 18% obtained by the CF/NF yield ratio of the S-type, without a significant difference between the two values. The slightly lower value for the OTC-based system may be due to the lower ozone levels in NF chambers due to losses in the ventilation system. Thus, both methods yielded equivalent yield reductions of about 20% due to ozone at this Mediterranean site. However, the higher air temperature inside OTCs influenced the plant growth, and this effect was stronger in the case of the R type. Therefore, R/S yield ratios in NF chambers differed from ambient air. Also, plant water consumption was higher in OTCs than in ambient air. The results suggest that the OTC-based method enables yield loss estimates at this Mediterranean site, in spite of chamber effects on plant growth and water use.  相似文献   

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