Chemical and C and N stable isotope compositions of three species of epiphytic Tillandsia in a Caribbean coastal zone: air pollution sources and biomonitoring implications

We characterized the elemental and C and N stable isotope compositions of Tillandsia fasciculata Sw., Tillandsia balbisiana Schult. & Schult.f. and Tillandsia recurvata (L.) L. samples collected in Cienfuegos (Cuba). Results showed high enrichment factors for S, Hg, Cd, Pb, P, Zn, Cu, Mo, Sb and Ca in all Tillandsia species, indicating inputs from local anthropogenic activities (road traffic, industries and cement production). Carbon concentrations and δ13C varied from 38.3-47.7 % and -20.4 to -13.4 ‰ within the three species, respectively. δ13C showed seasonal dependence with the dry and wet periods and more 13C-depleted values in urban/industrial areas, coherent with the input of anthropogenic emissions. Nitrogen concentrations (0.4-1.3 %) and δ15N values (-9.9-4.4 ‰) exhibit larger variations and are positively correlated in the three species. The most positive δ15N in T. recurvata (-0.2-4.4 ‰) are attributed to contributions from industrial activities and road traffic. In fact, both δ15N and total nitrogen (TN) values increase in sites with higher road traffic and show significant correlations with typical road traffic and industrial tracers. Finally, we calculate an average total nitrogen deposition rate of 4.4 ± 2.3 kg ha-1 a-1 from N content in T. recurvata, similar to the existing values determined in the region by field measurements, but higher than the global terrestrial average.

First assessment of atmospheric pollution by trace elements and particulate matter after a severe collapse of a tailings dam, Minas Gerais, Brazil: An insight into biomonitoring with Tillandsia usneoides and a public health dataset

In this study, samples of bromeliad Tillandsia usneoides (n = 70) were transplanted and exposed for 15 and 45 days in 35 outdoor residential areas in Brumadinho (Minas Gerais state, Brazil) after one of the most severe mining dam collapses in the world. Trace elements aluminum (Al), arsenic (As), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), manganese (Mn), nickel (Ni) and zinc (Zn) were quantified by atomic absorption spectrometry. Scanning electron microscope generated surface images of T. usneoides fragments and particulate matter (PM2.5, PM10 and PM > 10). Aluminum, Fe and Mn stood out from the other elements reflecting the regional geological background. Median concentrations in mg kg-1 increased (p < 0.05) between 15 and 45 days for Cr (0.75), Cu (1.23), Fe (474) and Mn (38.1), while Hg (0.18) was higher at 15 days. The exposed-to-control ratio revealed that As and Hg increased 18.1 and 9.4-fold, respectively, not showing a pattern associated only with the most impacted sites. The PM analysis points to a possible influence of the prevailing west wind on the increase of total particles, PM2.5 and PM10 in transplant sites located to the east. Brazilian public health dataset revealed increase in cases of some cardiovascular and respiratory diseases/symptoms in Brumadinho in the year of the dam collapse (1.38 cases per 1000 inhabitants), while Belo Horizonte capital and its metropolitan region recorded 0.97 and 0.37 cases, respectively. Although many studies have been carried out to assess the consequences of the tailings dam failure, until now atmospheric pollution had not yet been evaluated. Furthermore, based on our exploratory analysis of human health dataset, epidemiological studies are required to verify possible risk factors associated with the increase in hospital admissions in the study area.

GLUT4 translocation in C2C12 myoblasts and primary mouse hepatocytes by an antihyperglycemic flavone from Tillandsia usneoides

BACKGROUND

Type 2 Diabetes (T2D) is characterized by deregulation in carbohydrate and lipid metabolism, with a very high mortality rate. Glucose Transporter type 4 (GLUT4) plays a crucial role in T2D and represents a therapeutic target of interest. Tillandsia usneoides (T. usneoides) is a plant used as a remedy for diabetes. T. usneoides decreased blood glucose in different experimental models. However, the involvement of GLUT4 in this effect has not yet been explored.

PURPOSE

This study aimed to investigate whether any component in T. usneoides might participate in the effect on blood glucose through a bioassay-guided fractionation, testing its potential antihyperglycemic effect in mice, as well as its influence on GLUT4 translocation in C2C12 myoblasts and primary hepatocytes.

METHODS

The aqueous extract and the Ethyl Acetate fraction (TU-AcOEt) of T. usneoides were evaluated in a hypoglycemic activity bioassay and in the glucose tolerance test in CD-1 mice. TU-AcOEt was fractionated, obtaining five fractions that were studied in an additional glucose tolerance test. C1F3 was fractioned again, and its fractions (C2F9-12, C2F22-25, and C2F38-44) were examined by HPLC. The C2F38-44 fraction was analyzed by Mass Spectrometry (MS) and subjected to additional fractionation. The fraction C3F6-9 was explored by Nuclear Magnetic Resonance (NMR), resulting in 5,7,4´-trihydroxy-3,6,3´,5´-tetramethoxyflavone (Flav1). Subsequently, a viability test was performed to evaluate the cytotoxic effect of Flav1 and fractions C2F9-12, C2F22-25. C2F38-44, and C3F30-41 in C2C12 myoblasts and primary mouse hepatocytes. Confocal microscopy was also performed to assess the effect of Flav1 and fractions on GLUT4 translocation.

RESULTS

The TU-AcOEt fraction exhibited a hypoglycemic and antihyperglycemic effect in mice, and its fractionation resulted in five fractions, among which fraction C1F3 decreased blood glucose. MS and NMR analysis revealed the presence of Flav1. Finally, Flav1 significantly promoted the translocation of GLUT4 in C2C12 myoblasts and primary hepatocytes.

CONCLUSION

To date, Flav1 has not been reported to have activity in GLUT4; this study provides evidence that T. usneoides is a plant with the potential to develop novel therapeutic agents for the control of T2D.

Effect of trichome structure of Tillandsia usneoides on deposition of particulate matter under flow conditions

The removal of particulate matters (PM) has emerged as one of the most significant issues in public health and environment worldwide. Environmentalists have proposed the use of indoor air-purifying plants as an eco-friendly strategy to resolve PM-related problems and effectively remove fine particulate matter (PM_2.5). Among air-purifying plants, Tillandsia usneoides (L.) L. (T. usneoides) has been used as a biomonitor for heavy metals and air pollutants. However, the PM removal effect of T. usneoides and its primary mechanism remain unclear. Here, we investigated the PM removal performance of T. usneoides in a closed chamber under flow conditions, the effects of trichomes, and the array density according to the different types of PM. The chamber with bulk T. usneoides under flow conditions exhibited 16.5 % and 9.2 % higher removal efficiency in PM_2.5T. usneoides for incense and A1 rigid PM, respectively, than that without T. usneoides. T. usneoides with trichome structure exhibited larger removal efficiencies of 7% and 2% in PM_2.5 and PM₁₀, respectively, than without trichome for incense particles. In addition, the increase in total effective surface was effective for the deposition of both PM types. The increase in effective surface area by trichome structure and array density of T. usneoides is a crucial factor for the deposition of PM.

Tillandsia usneoides as biomonitors of trace elements contents in the atmosphere of the mining district of Cartagena-La Unión (Spain): New insights for element transfer and pollution source tracing

Nowadays, atmospheric pollution has a major impact on the human health and the environment, encouraging the development of biomonitors of the air quality over a wide zone. In this study, the relevance of the epiphyte plants Tillandsia usneoides is studied to estimate the transfer of metal(loid)s from a former Zn and Pb mining zone in the Southeast of Spain (Cartagena-La Unión) to the local atmosphere. Biomonitoring was performed by installing plants in 5 sites along a transect from the main mining area to the urban and the coastal zones. An aliquot of plants was collected in every site every 2 months over 1 year. The Tillandsia usneoides have been observed with SEM-EDX, and analysed by ICP-MS to determine trace element concentrations, magnetic susceptibility signals and Zn and Pb isotopes ratios. Results show that atmospheric particles are distributed homogeneously at the plant surface. By comparing elemental contents in Tillandsia usneoides with regard to the values of the geochemical background of the region of Murcia, significant enrichments are observed in the epiphyte plants for Sb, As, Cd, Zn and Pb. The statistical analyses (decentred PCA and PLS) also suggest that the kinetics of dust deposition is slower for the urban and coastal sites compared to the mining sites and highlight an influence of agricultural activities in Cu deposition. The similarity of isotopic compositions (Zn and Pb) between Tillandsia usneoides, soils and atmospheric particles also put in evidence that these plants could be a powerful tool to trace the source of matter in the atmosphere. Finally, this experiment provides new insight to better understand the foliar absorption mechanisms.

Perturbation vectors to evaluate air quality using lichens and bromeliads: a Brazilian case study

Samples of one lichen species, Parmotrema crinitum, and one bromeliad species, Tillandsia usneoides, were collected in the state of Rio de Janeiro, Brazil, at four sites differently affected by anthropogenic pollution. The concentrations of aluminum, cadmium, copper, iron, lanthanum, lead, sulfur, titanium, zinc, and zirconium were determined by inductively coupled plasma-atomic emission spectroscopy. The environmental diagnosis was established by examining compositional changes via perturbation vectors, an underused family of methods designed to circumvent the problem of closure in any compositional dataset. The perturbation vectors between the reference site and the other three sites were similar for both species, although body concentration levels were different. At each site, perturbation vectors between lichens and bromeliads were approximately the same, whatever the local pollution level. It should thus be possible to combine these organisms, though physiologically different, for air quality surveys, after making all results comparable with appropriate correction. The use of perturbation vectors seems particularly suitable for assessing pollution level by biomonitoring, and for many frequently met situations in environmental geochemistry, where elemental ratios are more relevant than absolute concentrations.

Richness, coverage and concentration of heavy metals in vascular epiphytes along an urbanization gradient

Richness, coverage and concentration of heavy metals in vascular epiphytes were analyzed in isolated trees along an urbanization gradient in Southern Brazil. A total of 20 phorophytes were sampled in the main street of each site. Concentrations of chromium, cadmium, lead, manganese, nickel and zinc were measured in the leaves of Tillandsia recurvata L. using Graphite Furnace Atomic Absorption Spectrophotometry. A decreasing gradient of epiphyte richness and coverage was observed as urbanization increased. Vehicle fleet and demographic density were the parameters most correlated with the reduction of epiphytic diversity. In T. recurvata, significantly higher values of cadmium, lead and zinc were recorded in the most urbanized areas, and were strongly related to the vehicle fleet and to the demographic density in these sites. The results demonstrated that these parameters could be applied to the diagnosis of environmental quality in urban areas, allowing standardized analyses in other regions.

The influence of atmospheric particles on the elemental content of vegetables in urban gardens of Sao Paulo, Brazil

Although urban horticulture provides multiple benefits to society, the extent to which these vegetables are contaminated by the absorption of chemical elements derived from atmospheric deposition is unclear. This study was designed to evaluate the influence of air pollution on leafy vegetables in community gardens of Sao Paulo, Brazil. Vegetable seedlings of Brassica oleracea var. acephala (collard greens) and Spinacia oleracea (spinach) obtained in a non-polluted rural area and growing in vessels containing standard uncontaminated soil were exposed for three consecutive periods of 30, 60 and 90 days in 10 community gardens in Sao Paulo and in one control site. The concentrations of 17 chemical elements (traffic-related elements and those essential to plant biology) were quantified by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Tillandsia usneoides L. specimens were used as air plant biomonitors. The concentrations of As, Cd, Cr and Pb found in vegetables were compared to the recommended values for consumption. Principal Component Analysis (PCA) was used to cluster the elemental concentrations, and Generalized Linear Models (GLMs) were employed to evaluate the association of the factor scores from each PCA component with variables such as local weather, traffic burden and vertical barriers adjacent to the gardens. We found significant differences in the elemental concentrations of the vegetables in the different community gardens. These differences were related to the overall traffic burden, vertical obstacles and local weather. The Pb and Cd concentrations in both vegetables exceeded the limit values for consumption after 60 days of exposure. A strong correlation was observed between the concentration of traffic-related elements in vegetables and in Tillandsia usneoides L. An exposure response was observed between traffic burden and traffic-derived particles absorbed in the vegetables. Traffic-derived air pollution directly influences the absorption of chemical elements in leafy vegetables, and the levels of these elements may exceed the recommended values for consumption.

Bioindicating potential of strontium contamination with Spanish moss Tillandsia usneoides

Tillandsia species have been recognized as efficient biomonitors of air pollution, but rarely exploited in bioindicating of strontium, an important nuclide. We exposed Tillandsia usneoides, colloquially known as Spanish moss due to its filamentous morphology but is an atypical angiosperm in the family Bromeliaceae, to the solutions with different Sr concentrations (0.1-100 mmol/L). The results showed that plants were able to endure Sr stress for a relatively long period, which suggests that T. usneoides is able to resist this toxic element. T. usneoides had the highest uptake ratio of Sr (82.21 ± 0.12%) when the plants were exposed to 0.1 mmol/L Sr solutions. Sr contents in T. usneoides increased significantly with the increase in applied metal solution concentrations. Low Sr stimulated the formation of chlorophyll, but high Sr decreased the contents of chlorophyll, and no significant effect on the total biomass was found in T. usneoides. In contrast, the permeability of plasma membrane based on the relative electronic conductivity in T. usneoides increased significantly under Sr stress, indicating that Sr probably caused oxidative stress. Moreover, correlation analysis showed that the leaf relative conductivity was significantly positively correlated with Sr contents in the plants after Sr treatments. Therefore, T. usneoides has considerable potential for monitoring Sr polluted environments through measuring Sr contents in the plant directly or exploiting the leaf relative conductivity as an indirect biomarker.

Tillandsia usneoides: a successful alternative for biomonitoring changes in air quality due to a new highway in São Paulo, Brazil

Tillandsia usneoides is an aerial epiphytic bromeliad that absorbs water and nutrients directly from the atmosphere by scales covering its surface. We expanded the use of this species as a broader biomonitor based on chemical and structural markers to detect changes in air quality. The usefulness of such comprehensive approach was tested during the construction and opening of a highway (SP-21) in São Paulo State, Brazil. The biomonitoring study was performed from 2009 to 2012, thus comprising the period during construction and after the highway inauguration. Metal accumulation and structural alterations were assessed, in addition to microscopy analyses to understand the metal chelation in plant tissues and to assess the causes of alterations in the number and shape of scale cells. Altogether, our analyses support the use of this species as a wide biomonitor of air quality in urbanized areas.

Antileukemic activity of Tillandsia recurvata and some of its cycloartanes

BACKGROUND

Approximately 250,000 deaths were caused by leukemia globally in 2012 and about 40%-50% of all leukemia diagnoses end-up in death. Medicinal plants are a rich source for the discovery of new drugs against leukemia and other types of cancers. To this end, we subjected the Jamaican ball moss (Tillandsia recurvata) and its cycloartanes, as well as some analogs, to in vitro screening against a number of leukemia cell lines. The WST-1 anti-proliferation assay was used to determine the anticancer activity of ball moss and two cycloartanes isolated from ball moss and four of their analogs against four leukemia cell lines (HL-60, K562, MOLM-14, monoMac6). Ball moss crude methanolic extract showed activity with a 50% inhibition concentration (IC50) value of 3.028 μg/ml against the Molm-14 cell line but was ineffective against HL-60 cells. The six cycloartanes tested demonstrated varying activity against the four leukemia cancer cell lines with IC50 values ranging from 1.83 μM to 18.3 μM. Five out of the six cycloartanes demonstrated activity, while one was inactive against all four cell lines. The preliminary activity demonstrated by the Jamaican ball moss and its cycloartanes against selected leukemia cell lines continues to throw light on the broad anticancer activity of ball moss. Further studies to evaluate the efficacy of these molecules in other leukemia cell lines are required in order to validate the activity of these molecules, as well as to determine their mechanisms of action and ascertain the activity in vivo in order to establish efficacy and safety profiles.

Two New 24-Isopropenyl-lanostanoids from Tillandsia brachycaulos

The leaves of Tillandsia brachycaulos afforded two novel tetracyclic triterpenoids identified as (24S)-24-isopropenyl-29-nor-5α-lanosta-7-en-3β-ol (1) and (24S)-24-isopropenyl-29-nor- 5α-lanosta-7-en-3-one (2), in addition to the known isopimaric acid (3) and chlorogenic acid (4). Their structures were elucidated on the basis of spectral analysis, including homo- and heteronuclear correlation NMR experiments (COSY, ROESY, HMQC and HMBC) and by comparison with data in the literature. The antimicrobial and antifungal activities were studied. The compounds did not show significant activity.

Potential of monitoring nuclides with the epiphyte Tillandsia usneoides: Uptake and localization of 133Cs

Epiphytic Tillandsia plants are efficient air pollution biomonitors and traditionally used to monitor atmospheric heavy metal pollution, but rarely nuclides monitoring. Here we evaluated the potential of Tillandsia usneoides for monitoring (133)Cs and investigated if Cs was trapped by the plant external surface structures. The results showed that T. usneoides was able to survive relatively high Cs stress. With the increase of Cs solution concentration, the total of Cs in plants increased significantly, which suggests that the plants could accumulate Cs quickly and effectively. Therefore, T. usneoides has considerable potential for monitoring Cs polluted environments. In addition, scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) analysis showed that Cs was detected in each type of cells in foliar trichomes, and the ratio of Cs in the internal disc cell was higher than that in ring cell and wing cell, which indicates that the mechanism of adsorption Cs in Tillandsia has an active component.

Kinase inhibition by the Jamaican ball moss, Tillandsia recurvata L

BACKGROUND

This research was undertaken in order to investigate the inhibitory potential of the Jamaican ball moss, Tillandsia recurvata against several kinases. The inhibition of these kinases has emerged as a potential solution to restoring the tight regulation of normal cellular growth, the loss of which leads to cancer cell formation.

MATERIALS AND METHODS

Kinase inhibition was investigated using competition binding (to the ATP sites) assays, which have been previously established and authenticated.

RESULTS

Four hundred and fifty one kinases were tested against the Jamaican ball moss extract and a dose-response was tested on 40 kinases, which were inhibited by more than 35% compared to the control. Out of the 40 kinases, the Jamaican ball moss selectively inhibited 5 (CSNK2A2, MEK5, GAK, FLT and DRAK1) and obtained Kd(50)s were below 20 μg/ml.

CONCLUSION

Since MEK5 and GAK kinases have been associated with aggressive prostate cancer, the inhibitory properties of the ball moss against them, coupled with its previously found bioactivity towards the PC-3 cell line, makes it promising in the arena of drug discovery towards prostate cancer.

Antioxidant response of three Tillandsia species transplanted to urban, agricultural, and industrial areas

To evaluate the physiological response of Tillandsia capillaris Ruiz & Pav. f. capillaris, T. recurvata L., and T. tricholepis Baker to different air pollution sources, epiphyte samples were collected from a noncontaminated area in the province of Córdoba (Argentina) and transplanted to a control site as well as three areas categorized according to the presence of agricultural, urban, and industrial (metallurgical and metal-mechanical) emission sources. A foliar damage index (FDI) was calculated with the physiological parameters chlorophyll a, chlorophyll b, malondialdehyde (MDA), hydroperoxyconjugated dienes, sulfur (S) content, and dry weight-to-fresh weight ratio. In addition, electrical conductivity (E-cond), relative water content (RWC), dehydration kinetics (Kin-H(2)O), total phenols (T-phen), soluble proteins (S-prot), and activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase were determined. The parameters E-cond, FDI, SOD, RWC, and Kin-H(2)O can serve as suitable indicators of agricultural air pollution for T. tricholepis and T. capillaris, and CAT, Kin-H(2)O, and SOD can do the same for T. recurvata. In addition, MDA, T-phen, and S-prot proved to be appropriate indicators of urban pollution for T. recurvata. Moreover, FDI, E-cond, and SOD for T. recurvata and MDA for T. tricholepis, respectively, could be used to detect deleterious effects of industrial air pollution.

Bioindication of atmospheric trace metals--with special references to megacities

After considering the particular problems of atmospheric pollution in megacities, i.e. agglomerations larger than 5 mio. inhabitants, with urbanization of World's population going on steadily, possibilities of active biomonitoring by means of green plants are discussed. Based on specific definitions of active and passive bioindication the chances of monitoring heavy metals in Sao Paulo megacity were demonstrated (first results published before). This is to show that there is need for increased use of bioindication to tackle the particular problems of megacities concerning environmental "health", the data to be processed according to the Multi-Markered-Bioindication-Concept (MMBC). Comparison to other work shows this approach to be reasonable.

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.

Comparison of the air pollution biomonitoring ability of three Tillandsia species and the lichen Ramalina celastri in Argentina

Bioaccumulation ability and response to air pollution sources were evaluated for Tillandsia capillaris Ruíz and Pav. f. capillaris, T. recurvata L., T. tricholepis Baker and the lichen Ramalina celastri (Spreng.) Krog. and Swinsc. Epiphyte samples collected from a non contaminated area in the province of Córdoba were transplanted to a control site and three areas categorised according to agricultural, urban and industrial (metallurgical and metal-mechanical) emission sources. Bioindicators were exposed for 3-, 6- and 9-month periods. A foliar damage index was established for Tillandsia and a pollution index for the lichen, and S, Fe, Mn and Zn concentrations were determined. An order of efficiency for the species and conditions studied is proposed taking into account heavy metal accumulation: T. recurvata >T. tricholepis >R. celastri >T. capillaris. All species studied showed Mn to be related to agricultural activity and Fe to industries and soil particles, and Zn was related to urban and industrial sources. As far as physiological response is concerned, T. tricholepis and T. capillaris were more sensitive to agricultural activities, whereas T. recurvata was sensitive to urban and industrial sources, and only partially to agricultural sources. No relationship was found for R. celastri.

Assessment of atmospheric metallic pollution in the metropolitan region of São Paulo, Brazil, employing Tillandsia usneoides L. as biomonitor

Tillandsia usneoides L. is an epiphytic bromeliad plant able to absorb water and nutrients directly from the air. For this reason this species was selected to carry out a monitoring study of air pollution in the metropolitan region of São Paulo, Brazil. Five consecutive transplantation experiments (8 weeks each) were performed in 10 sites of the city, submitted to different sources of air pollution (industrial, vehicular), using plants collected from an unpolluted area. After exposure, trace metals were analyzed in the plant by instrumental neutron activation analysis. Traffic-related elements such as Zn and Ba presented high concentrations in exposure sites near to heavy traffic avenues (cars, buses and trucks) and may be associated to vehicular sources. For Zn and Co the highest contents were related to industrial zones and can be associated to the presence of anthropogenic emission sources. The rare earth elements, Fe and Rb, probably have soil particles as main source.

Mineral dynamics in Spanish moss, Tillandsia usneoides L. (Bromeliaceae), from Central Florida, USA

Epiphytes absorb water and nutrients from the atmosphere through precipitation and dry deposition and from their hosts through stemflow and throughfall. These commensals have been used as biological indicators or monitors of air quality. To measure temporal changes in Spanish moss (Tillandsia usneoides) mineral concentrations, we revisited sites in Central Florida where this epiphyte was collected and analyzed in 1973/1974. After 24-25 years, using comparable methods, concentrations of Ca, Mg, K and Cu decreased in the tissue samples while Fe increased. These declines in base cations corresponded to global atmospheric decreases. In the earlier study, patterns of elemental concentrations in Spanish moss corresponded to the host tree categories primarily reflecting a P gradient that increased from pine (Pinus spp.) to cypress (Taxodium spp.) to hardwood (e.g. Quercus spp.) hosts. Such host-specific associations were mostly absent from the recent study, suggesting that epiphytic preferences based on the chemistry of phorophyte leachates have become less important in this region, perhaps, resulting from local (suburbanization) or regional (atmospheric composition) changes.

The use of tropical bromeliads (Tillandsia spp.) for monitoring atmospheric pollution in the town of Florence, Italy

The results of an experiment with two species of epiphytic angiosperms (Tillandsia caput-medusae and T. bulbosa) for monitoring polycyclic aromatic hydrocarbons (PAHs) in the air of Florence, Italy, are presented. PAHs are compounds known to be dangerous because of their carcinogenic potential, and among cormophytes, tillands (monocotyledons equipped with peculiar, specialised, epidermal trichomes) are considered promising for air pollution biomonitoring. PAHs data were obtained using GC/MS analysis of plant extracts. Analytical data indicated an increasing trend in time of PAHs bioaccumulation. This result was compared with instrumentally recorded parameters such as meteorological (rain) and environmental ones (PM10), indicating that trichome-operated physical capture of aerial particles was prominent in PAHs bioaccumulation on tillands. SEM (scanning electron microscope) observations confirmed the role of the trichomes. This work indicates that tillands are particularly useful, low-cost biomonitoring organisms inside their area of distribution (all Latin American countries and southern USA) where these plants are easily available, but also wherever the climate allows them to survive.

Atmospheric quality and distribution of heavy metals in Argentina employing Tillandsia capillaris as a biomonitor

The atmospheric quality and distribution of heavy metals were evaluated throughout a wide region of Argentina. In addition, the biomonitor performance of Tillandsia capillaris Ruiz & Pav. f. capillaris was studied in relation to the accumulation of heavy metals and to its physiologic response to air pollutants. A sampling area of 50,000 km2 was selected in the central region of the Argentine Republic. This area was subdivided into grids of 25 x 25 km. Pools of T. capillaris, where present, were collected at each intersection point. From each pool three sub-samples were analyzed independently. Furthermore, five replicates were collected at 20% of the points in order to analyze the variability within the site. The content of Co, Cu, Fe, Ni, Mn, Pb and Zn was determined by Atomic Absorption Spectrometry. Chemical-physiological parameters were also determined to detect symptoms of foliar damage. Chlorophylls, phaeophytins, hydroperoxy conjugated dienes, malondialdehyde and sulfur were quantified in T. capillaris. Some of these parameters were used to calculate a foliar damage index. Data sets were evaluated by one-way ANOVA, correlation analysis, principal component analysis and mapping. Geographical distribution patterns were obtained for the different metals reflecting the contribution of natural and anthropogenic emission sources. According to our results it can be inferred that Fe, Mn and Co probably originated in the soil. For Pb, the highest values were found in the mountainous area, which can be attributed to the presence of Pb in the granitic rocks. Ni showed mainly an anthropogenic origin, with higher values found in places next to industrial centers. For Zn the highest values were in areas of agricultural development. The same was observed for Cu, whose presence could be related to the employment of pesticides. The foliar damage index distribution map showed that the central and southeastern zones were the ones where the major damage in the bioindicator was found. The central zone coincides with the city of Córdoba whereas the southeastern area is strictly agricultural, so the high values found there could be related to the use of pesticides.

Elemental mercury contamination survey in a chlor-alkali plant by the use of transplanted Spanish moss, Tillandsia usneoides (L.)

Atmospheric Hg0 contamination and the potential risk of occupational exposure were evaluated in a chlor-alkali facility by the use of transplanted Tillandsia usneoides. This plant species was selected since it presents some features that makes it useful for air monitoring purposes. After short-term exposure (15 days), control plants showed a mean concentration of 0.2 microgram Hg.g-1 whereas Hg values in transplants ranged from 1 to 10,400 micrograms.g-1. This latter value was observed near an elemental Hg spillage. Even after exposure to toxic conditions plant metabolism was still operative, allowing the transplant technique to be employed to assess both Hg taken up through the stomata and Hg associated with particles deposited on the biomonitor.