Effects of elevated CO2 concentrations and fly ash amended soils on trace element accumulation and translocation among roots, stems and seeds of Glycine max (L.) Merr.

The carbon dioxide (CO(2)) levels of the global atmosphere and the emissions of heavy metals have risen in recent decades, and these increases are expected to produce an impact on crops and thereby affect yield and food safety. In this study, the effects of elevated CO(2) and fly ash amended soils on trace element accumulation and translocation in the root, stem and seed compartments in soybean [Glycine max (L.) Merr.] were evaluated. Soybean plants grown in fly ash (FA) amended soil (0, 1, 10, 15, and 25% FA) at two CO(2) regimes (400 and 600 ppm) in controlled environmental chambers were analyzed at the maturity stage for their trace element contents. The concentrations of Br, Co, Cu, Fe, Mn, Ni, Pb and Zn in roots, stems and seeds in soybeans were investigated and their potential risk to the health of consumers was estimated. The results showed that high levels of CO(2) and lower concentrations of FA in soils were associated with an increase in biomass. For all the elements analyzed except Pb, their accumulation in soybean plants was higher at elevated CO(2) than at ambient concentrations. In most treatments, the highest concentrations of Br, Co, Cu, Fe, Mn, and Pb were found in the roots, with a strong combined effect of elevated CO(2) and 1% of FA amended soils on Pb accumulation (above maximum permitted levels) and translocation to seeds being observed. In relation to non-carcinogenic risks, target hazard quotients (TQHs) were significant in a Chinese individual for Mn, Fe and Pb. Also, the increased health risk due to the added effects of the trace elements studied was significant for Chinese consumers. According to these results, soybean plants grown for human consumption under future conditions of elevated CO(2) and FA amended soils may represent a toxicological hazard. Therefore, more research should be carried out with respect to food consumption (plants and animals) under these conditions and their consequences for human health.

Accumulation of polycyclic aromatic hydrocarbons and trace elements in the bioindicator plants Tillandsia capillaris and Lolium multiflorum exposed at PM10 monitoring stations in Stuttgart (Germany).

The accumulation of polycyclic aromatic hydrocarbons (PAHs) in Tillandsia capillaris Ruiz and Pav. form capillaris and trace elements in T. capillaris and Lolium multiflorum (LAM) cv. Lema was assessed and evaluated in the city of Stuttgart, Germany. Several sites (urban, suburban and rural) categorized according to type and intensity of vehicular traffic were investigated. At these sites, plants of T. capillaris and standardized cultures of L. multiflorum were exposed to ambient air. Foliar concentrations of PAHs (16 priority pollutants according to US-EPA) and of the trace elements Br, Co, Cu, Fe, Mn, Ni, Pb and Zn were determined. A high level of vehicular traffic was associated with the largest concentrations of PM(10) in ambient air and with the highest contents of PAHs and heavy metals in the bioindicator plants. The results showed a similar pattern between T. capillaris and the standardized biomonitor L. multiflorum. Therefore, these results allow us to propose T. capillaris as a suitable bioindicator to assess the distribution of pollution impacts caused by PAHs and trace elements in different subtropical and tropical regions.

Environmental monitoring of fluoride emissions using precipitation, dust, plant and soil samples.

A pollution gradient was observed in precipitation, plants and soils sampled at different locations around a fluoride producing chemical plant in Germany. In all samples the influence of emissions was discernible up to a distance of 500 m from the plant. However, fluoride concentrations in plant bioindicators (leaves of birch and black berry) and in bulk precipitation showed a more pronounced relationship with the distance from the source than fluoride concentrations in soil. Vegetables sampled in the vicinity of the plant also had elevated concentrations of fluoride, but only the consumption of larger quantities of this material would lead to exceedances of recommended daily F-intake. The present study did not indicate the existence of low phytotoxicity thresholds for fluoride in the plant species used in the study. Even at very high fluoride concentrations in leaf tissue (963 ppm) plants did not show injury due to HF. Dust sampling downwind of the chemical plant confirmed that particulate fluoride was of minor importance in the study area.

Hypoxia-induced cell death in human malignant glioma cells: energy deprivation promotes decoupling of mitochondrial cytochrome c release from caspase processing and necrotic cell death.

Hypoxia induces apoptosis in primary and transformed cells and in various tumor cell lines in vitro. In contrast, there is little apoptosis and predominant necrosis despite extensive hypoxia in human glioblastomas in vivo. We here characterize ultrastructural and biochemical features of cell death in LN-229, LN-18 and U87MG malignant glioma cells in a paradigm of hypoxia with partial glucose deprivation in vitro. Electron microscopic analysis of hypoxia-challenged glioma cells demonstrated early stages of apoptosis but predominant necrosis. ATP levels declined during hypoxia, but recovered with re-exposure to normoxic conditions unless hypoxia exceeded 8 h. Longer hypoxic exposure resulted in irreversible ATP depletion and delayed cell death. Hypoxia induced mitochondrial release of cytochrome c, but there was no cleavage of caspases 3, 7, 8 or 9, and no DNA fragmentation. Ectopic expression of BCL-XL conferred protection from hypoxia-induced cell death, whereas the overexpression of the antiapoptotic proteins X-linked-inhibitor-of-apoptosis-protein and cytokine response modifier-A had no effect. These findings suggest that glioma cells resist adverse effects of hypoxia until energy stores are depleted and then undergo necrosis rather than apoptosis because of energy deprivation.

Tropical fruit trees as bioindicators of industrial air pollution in southeast Brazil.

Psidium guajava L., Psidium cattleyanum Sabine and Mangifera indica L. were tested under field conditions as possible tropical bioindicators of industrial air pollution. The study was performed around the industrial complex of Cubatão, SE Brazil, which comprises 23 industries, including fertilizer, cement, chemical, petrochemical, and steel plants, with 110 production units and 260 emission sources of pollutants. Saplings were exposed to environmental conditions during four periods of 16 weeks each (September 1994-September 1995), at four different sites in the coastal mountains near the industrial complex: the Valley of Pilões River (VP), the reference area; the Valley of Mogi River (VM), with high contamination of particulate matter, fluorides (F), sulfur (S) and nitrogen (N) compounds; Caminho do Mar (CM1, CM2), mainly affected by organic pollutants, S and N compounds, and secondary pollutants; and Paranapiacaba (PP), affected by secondary pollutants, such as ozone. M. indica did not adapt to the climatic conditions at the exposure sites. In the two Psidium species, the presence of visible symptoms, root/shoot ratio, foliar contents of F, S and N, amounts of ascorbate (AA) and water-soluble thiols (-SH), as well as peroxidase activity (POD) were determined. P. guajava showed higher foliar accumulation of F, S and N, more pronounced alterations of biochemical indicators, and less visible leaf injury than P. cattleyanum. P. guajava may be used as an accumulative indicator in tropical climates, while further studies will be needed before P. cattleyanum might be applied as a sensitive species in biomonitoring programs.

EuroBionet: a pan-European biomonitoring network for urban air quality assessment.

EuroBionet, the 'European Network for the Assessment of Air Quality by the Use of Bioindicator Plants', is an EU-funded cooperative project currently consisting of public authorities and scientific institutes from 12 cities in 8 countries. In 2000, the bioindicator plants tobacco (Nicotiana tabacum Bel W3), poplar (Populus nigra 'Brandaris'), spiderwort (Tradescantia sp. clone 4430), Italian rye grass (Lolium multiflorum italicum) and curly kale (Brassica oleracea acephala) were exposed to ambient air at 90 monitoring sites according to standardised methods. Visible injuries and growth parameters were assessed and the accumulation of toxic substances in leaves determined. The exposure of tobacco resulted in a gradient with low levels of ozone-induced foliar injury in N and NW Europe, and medium to high values in the southern and central regions. The results of heavy metal and sulphur analyses in rye grass samples generally showed low to very low sulphur and low to medium heavy metal concentrations in leaves. In some cities, however, local hot spots of heavy metal contamination were detected. Analyses of the PAH contents in curly kale leaves gave low to medium values, with locally elevated levels at traffic-exposed sites.

APRIL, a new member of the tumor necrosis factor family, modulates death ligand-induced apoptosis.

APRIL (a proliferation-inducing ligand) is a newly identified member of the tumor necrosis factor (TNF) family. Tumor growth-promoting as well as apoptosis-inducing effects of APRIL have been described. Here, we report that five of 12 human malignant glioma cell lines express APRIL. APRIL gene transfer experiments revealed that malignant glioma cells are refractory to growth-promoting activity of APRIL in vitro and in vivo. Interestingly, ectopic expression of APRIL confers minor protection from apoptotic cell death induced by the death ligands, CD95 ligand (CD95L) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)/Apo2 ligand (Apo2L). This antiapoptotic activity is specific for death ligand/receptor-mediated apoptosis since APRIL does not protect glioma cells from the cytotoxicity of the drugs, teniposide, vincristine, lomustine or cisplatin. Ectopic expression of APRIL is associated with the upregulation of X-linked inhibitor of apoptosis protein (XIAP), providing a possible explanation for the antiapoptotic activity observed here. In contrast, APRIL does not regulate the expression levels of the antiapoptotic proteins FLICE-inhibitory protein (FLIP), Bcl-2 or Bcl-X(L). These findings suggest that APRIL is involved in the regulation of death ligand-induced apoptotic signaling in malignant glioma cells.

Response of stress indicators and growth parameters of Tibouchina pulchra Cogn. exposed to air and soil pollution near the industrial complex of Cubatão, Brazil.

The present study was performed in the vicinity of the industrial complex of Cubatão, São Paulo, Brazil, in order to evaluate the response of 'manaca da serra' Tibouchina pulchra Cogn. (Melastomataceae), a common species of secondary Atlantic Rain Forest vegetation, to the impact of complex air pollution. Emphasis was given to changes of biochemical parameters such as ascorbic acid concentration, peroxidase activity, contents of water-soluble thiols, pH of leaf extract and buffering capacity. These plant factors are often used as early indicators of air pollution stress. Field experiments included sampling of leaves from mature trees in areas with different air pollution load (passive monitoring), exposure of saplings cultivated in uniform soil at these areas (active monitoring) and a study on the combined effects of contaminated soil and air pollution. In general, metabolic response of saplings was more accentuated than that of mature trees. Leaf extract pH and buffering capacity showed no or only small alterations in plants exposed to industrial emissions. In contrast, air pollution resulted in a distinct decrease in ascorbic acid contents and an increase in peroxidase activity and thiol concentrations in leaves. Cultivation of saplings in soil types from contaminated regions frequently caused the same modifications or enhanced the effects produced by air pollution. Growth analysis of exposed saplings demonstrated that a change of the relationship between above-ground and below-ground plant parts was the most obvious effect of air pollution and soil contamination. The experiments showed that even T. pulchra, a species considered resistant to air pollution, suffers metabolic disturbances by the present ambient air and soil quality. Although biochemical and physiological alterations were not related to a certain air pollution type, they could be used to estimate the overall pollution load and to map zones with different air quality.

Hemerocallis as bioindicator of fluoride pollution in tropical countries.

In the frame of an active monitoring study at the Serra do Mar near the industrial pool of Cubatão, Brazil,Hemerocallis was tested for its suitability as bioindicator of airborne fluoride pollution. In a screening experiment with various cultivars comparison of susceptibility, correlation of visible injury and foliar fluoride concentration as well as comparison with exposure ofGladiolus gave best results for theHemerocallis cultivar 'Red Moon'. When exposed simultaneously foliar fluoride accumulation ofHemerocallis showed a highly significant linear correlation with fluoride content ofLolium multiflorum, the 'standardized grass culture' andGladiolus, well-known bioindicator species for fluoride impact. With respect to the extent of foliar injuryHemerocallis was less sensitive thanGladiolus, in terms of accumulation capacity it ranged betweenLolium andGladiolus. In general, the results of the biomonitoring study proved that the Atlantic Forest vegetation in a valley downwind from the Cubatão fertilizer industries is still suffering from severe fluoride pollution.

Plants as bioindicators of air pollution at the Serra do Mar near the industrial complex of Cubatão, Brazil.

As a result of air pollutant emissions from the industrial complex of Cubatão, Brazil, the Atlantic Forest vegetation of the Serra do Mar shows severe and widespread damage. In order to obtain information on the type, intensity and causes of the vegetation damage, bioindicator plants were exposed at different distances from the emission sources. Air-pollution-induced effects were evaluated by estimation of visible injury symptoms and chemical analyses of leaves. The results prove the occurrence of phytotoxic levels of photochemical oxidants in wide parts of the research area. Intense fluoride-induced damage and high leaf fluoride concentrations were found in a valley downwind of fertiliser industries. The study showed that some of the traditional standardised bioindication methods from temperate climates may be successfully employed in biomonitoring programmes in tropical and subtropical regions.

Nitrate reductase activity of needles of Norway spruce fumigated with different mixtures of ozone, sulfur dioxide, and nitrogen dioxide.

Four-year-old spruce clones (Picea abies (L.) Karst.) cultivated in sand and provided with a complete nutrient solution, or a solution deficient in magnesium and calcium, were exposed to the pollutant mixtures SO(2)/NO(2), O(3)/NO(2), and O(3)/SO(2)/NO(2), at realistic concentrations for 32 weeks. Fumigation caused a slight increase of total N contents in current year needles, whereas in one-year-old needles N concentrations did not change. The response of nitrate reductase activity to pollutant stress depended on needle age and nutrient supply, respectively. In one-year-old needles fumigation resulted in a significant inhibition of enzyme activity, particularly in Mg and Ca deficient trees. The combination of all three components proved to be most effective in causing a decrease by 60% compared to the control. In contrast, nitrate reductase activity was stimulated in current year needles, especially by O(3)/NO(2) and O(3)/SO(2)/NO(2). Changes in the activity of nitrate and nitrite reductases are considered as a factor contributing to the high phytotoxic potential of pollutant combinations with NO(2).