RESUMEN

Plants can 'catch' and mitigate airborne pollutants and are assisted by fungi inhabiting their leaves. The structure and function of the fungal communities inhabiting the phyllosphere of hornbeam trees growing in two chronically polluted areas, the oilfield of Bóbrka and the city center of Warsaw, were compared to the ones growing in one nature reserve, the Bialowieza National Park. Fungi were isolated and characterized both phylogenetically and functionally for their potential role in air pollution mitigation. Both culture-dependent (e.g., enzyme assays and tolerance tests) and culture-independent methods (e.g., ITS and shotgun sequencings) were used. Furthermore, the degradation potential of the fungi was assessed by gas chromatography mass spectrometry (GC-MS). Shotgun sequencing showed that the phyllosphere fungal communities were dominated by fungi belonging to the phylum Ascomycota. Aureobasidium was the only genus detected at the three locations with a relative abundance ≥1.0%. Among the cultivated epiphytic fungi from Bóbrka, Fusarium sporotrichioides AT11, Phoma herbarum AT15, and Lophiostoma sp. AT37 showed in vitro aromatic hydrocarbon degradation potential with laccase activities of 1.24, 3.62, and 7.2 µU L-1, respectively, and peroxidase enzymes with activities of 3.46, 2.28, and 7.49 µU L-1, respectively. Furthermore, Fusarium sporotrichioides AT11 and Phoma herbarum AT15 tolerated exposure to airborne naphthalene and benzene. Lophiostoma sp. AT37 was the most tolerant to exposure to these pollutants, in line with being the best potential aromatic hydrocarbon degrader isolated in this study.

RESUMEN

Urban green areas are highly valued by citizens for their contribution to the quality of life in cities. Plants play an important role in mitigating airborne pollutants and are assisted in this role by the metabolic capacities of the millions of microbial cells that colonize leaf surfaces (phyllosphere). Many factors influence phyllosphere microbial community composition and function, but to what extent does airborne pollution in cities impact the composition of microbial communities and their functional degradation genes? Here we describe the characterization of the phyllospheric bacterial communities of Carpinus betulus L. trees (hornbeam) across three locations: the city center of Warsaw (Poland), a forest in a UNESCO World Heritage Site (Bialowieza), and a forest in one of the world's oldest operational oil fields (Bóbrka). C. betulus contained higher particulate matter (PM) concentrations, with higher concentrations of palladium and radon in the PM, on leaves in Warsaw than in the forests. Volatile organic compound (VOC) analyses of sampled air revealed higher concentrations of butanone methyl propanal, butylbenzene, and cyclohexane in Bóbrka than Warsaw and Bialowieza, while in Warsaw, xylene and toluene were higher. Shotgun microbiome sequencing uncovered a dominance of Gammaproteobacteria (71%), mainly Pseudomonas spp., Actinobacteria, Alpha- and Betaproteobacteria, and Firmicutes. Community composition and function differed significantly between the forests and Warsaw city center. Statistically more hydrocarbon degradation genes were found in Bialowieza compared to Warsaw and Bóbrka, and in vitro tests of diesel degradation and plant growth promotion traits of culturable representatives revealed that Bialowieza held the highest number of bacteria with plant beneficial properties and degradation genes. This study provides the first detailed insights into the microbiome of C. betulus and sets the stage for developing to a more integrated understanding of phyllosphere microbiota in cities, and their relationships with human health.

RESUMEN

Hydrocarbon-degrading bacteria are important resources for use in phytoremediation applications. Yet, for many hydrocarbonoclastic strains the genetic information regarding pollutant degradation and detoxification has not been thoroughly revealed. In this study, hydrocarbon-degrading bacteria were isolated from a long-term oil-polluted soil in Bóbrka, Poland. Pseudomonas spp. was the most dominant species. Of all 69 isolated strains tested in the laboratory using qualitative biochemical assays, 61% showed the capability to use diesel as sole carbon source, 33% could produce indole, 19% produced siderophores, 36% produced organic acids, and 54% were capable of producing 1-aminocyclopropane-1-carboxylate (ACC)-deaminase. From all morphologically and genetically different strains, two representative Pseudomonas spp., strain VI4.1 and VI4T1, were selected for genome sequencing. Genomic analyses indicated the presence of the full naphthalene dioxygenase operon (plasmid and chromosomal), of genes involved in the degradation of BTEX compounds (Benzene, Toluene, Ethylbenzene, Xylene) and alkanes (alkB gene) as well as the anthranilate degradation pathway (strain VI4T1) and terephthalate dioxygenase protein (strain VI4.1). Proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) analyses confirmed naphthalene and BTEX degradation within seven days. Motility, resistance to abiotic stresses, high and low temperatures, low pH, and salinity were confirmed at the genetic level and experimentally verified. The presence of multiple degradative and plant growth promotion genes, together with the in vitro experimental evidence, indicates the high value of these two strains and their potential use for sustainable site clean-up.

Asunto(s)

RESUMEN

Platinum (Pt) occurs at very low levels in parent rock and soils in unpolluted areas, however concentrations of this element in urban areas is steadily increasing. At the levels recorded in urban environments, Pt is not yet phytotoxic, but it already poses a threat to human health, particularly when present in airborne particulate matter. In this study an attempt was made to evaluate Pt(II) uptake, distribution and toxicity in Arabidopsis thaliana L. plants. Arabidopsis thaliana plants were hydroponically grown with increasing Pt(II) concentrations in the range of 0.025-100µM. Pt(II) was taken up by the roots and translocated to the rosette. At lower Pt(II) concentrations (≤ 2.5µM) hormesis was recorded, plant growth was stimulated, the efficiency of the photosynthetic apparatus improved and biomass accumulation increased. Higher Pt(II) concentrations were phytotoxic, causing growth inhibition, impairment of the photosynthetic apparatus, membrane injuries and a reduction in biomass accumulation. Exposure of A. thaliana to Pt(II) also resulted in an increased content of phytochelatins throughout the plant and glutathione in the rosette. Uptake and translocation of Pt(II) to harvestable organs of A. thaliana suggests that species of higher biomass accumulation from the Brassicaceae family can probably be used for the phytoextraction of Pt-polluted sites.

Asunto(s)

RESUMEN

Particulate matter (PM) is one of the most harmful inhaled pollutants. When pollutants are emitted into the atmosphere, the only possible method for cleaning the air is through phytoremediation, where plants act as biological filters for pollutants. However, PM also has negative impacts on plants, although knowledge concerning the effects of PM on vegetation remains limited. In this work, an attempt was therefore made to define the amount of PM and waxes on foliage, and to evaluate the efficiency of the photosynthetic apparatus in seven plant species (three trees, three shrubs and one climber) grown in two locations (centre and suburbs of Warsaw) that differed in their level of PM pollution in the air. More PM and waxes accumulated on the foliage of plants grown in the highly polluted location. These plants also exhibited a lowered efficiency of their photosynthetic apparatus, manifested by a lower photosynthesis rate that corresponded with an increased stomatal resistance. Plants grown in the more polluted environment also showed decreased values of Fv/Fm parameter and no statistically significant trend to increase total chlorophyll content. Among the tested species, Betula pendula Roth accumulated the greatest amount of PM and Physocarpus opulifolius L. showed no weakening of its parameters of photosynthesis in a more contaminated environment.

Asunto(s)

RESUMEN

Particulate matter (PM) deposited on Platanus acerifolia tree leaves has been sampled in the urban areas of 28 European cities, over 20 countries, with the aim of testing leaf deposited particles as indicator of atmospheric PM concentration and composition. Leaves have been collected close to streets characterized by heavy traffic and within urban parks. Leaf surface density, dimensions, and elemental composition of leaf deposited particles have been compared with leaf magnetic content, and discussed in connection with air quality data. The PM quantity and size were mainly dependent on the regional background concentration of particles, while the percentage of iron-based particles emerged as a clear marker of traffic-related pollution in most of the sites. This indicates that Platanus acerifolia is highly suitable to be used in atmospheric PM monitoring studies and that morphological and elemental characteristics of leaf deposited particles, joined with the leaf magnetic content, may successfully allow urban PM source apportionment.

Asunto(s)

RESUMEN

BACKGROUND: Two-thirds of the world's population do not consume the recommended amount of Mg, hence the demand for the production of Mg-enriched plants. Sprouts represent promising targets for enrichment. This study evaluated the effects of enriching broccoli, radish, alfalfa and mung bean sprouts with Mg (50-300 mg L(-1) ) on (i) the concentration of Mg and other ions, (ii) biomass accumulation, (iii) levels of reactive oxygen species (ROS), and (iv) the activity/content of enzymatic and non-enzymatic components of antioxidative systems. RESULTS: Enrichment of sprouts with Mg led to a significant increase in Mg concentration, especially in alfalfa (increase of 23-152 %), without depletion of other ions. A higher Mg concentration had a minor effect on biomass accumulation, but increased, often significantly, ROS generation and affected enzymatic and non-enzymatic antioxidative systems. The level of O2 (•-) increased most in broccoli, by 59-158%, while OH(•) increased most in radish, by 200-350%. CONCLUSIONS: Enrichment of sprouts with Mg is possible, but attention must be paid to elevated ROS levels in food. Mung bean sprouts are best suited to enrichment as they make a considerable contribution to the daily supplementation of Mg, at still low levels of ROS in enriched plants. © 2015 Society of Chemical Industry.

Asunto(s)

RESUMEN

Since air pollution has been linked to a plethora of human health problems, strategies to improve air quality are indispensable. Despite the complexity in composition of air pollution, phytoremediation was shown to be effective in cleaning air. Plants are known to scavenge significant amounts of air pollutants on their aboveground plant parts. Leaf fall and runoff lead to transfer of (part of) the adsorbed pollutants to the soil and rhizosphere below. After uptake in the roots and leaves, plants can metabolize, sequestrate and/or excrete air pollutants. In addition, plant-associated microorganisms play an important role by degrading, detoxifying or sequestrating the pollutants and by promoting plant growth. In this review, an overview of the available knowledge about the role and potential of plant-microbe interactions to improve indoor and outdoor air quality is provided. Most importantly, common air pollutants (particulate matter, volatile organic compounds and inorganic air pollutants) and their toxicity are described. For each of these pollutant types, a concise overview of the specific contributions of the plant and its microbiome is presented. To conclude, the state of the art and its related future challenges are presented.

Asunto(s)

RESUMEN

One of the most dangerous inhaled pollutants is particulate matter (PM). PM in inhaled air have a negative impact on human wellbeing and health, and may even cause deaths. Where pollutants have been emitted into the outdoor atmosphere, the only possible method for cleaning the air is through phytoremediation, a form of environmental biotechnology, where plants act as biological filters for pollutants. This study compared PM levels on the leaves of Tilia cordata Mill. trees growing in locations at increasing distances from the source of the PM emission. Significant differences between individual trees growing at a distance of between 3 m and 500 m from the road edge were found in: (i) the mass of PM that accumulated on leaves (total, surface, in-wax and the three determined size fractions) and (ii) the amount of waxes deposited on leaves.

Asunto(s)

RESUMEN

Particulate matter (PM) as an air pollutant can be harmful for human health through allergic, mutagenic and carcinogenic effects. Although the main focus is on decreasing air pollution, after PM has been emitted to the atmosphere, one ofthe realistic options to decrease it's concentrations in urbanized area will be phytoremediation. This study compared the capacity to capture PM from air of seven tree species commonly cultivated in Poland (Catalpa bignonioides Walter, Corylus colurna L., Fraxinus pennsylvanica Marsh., Ginkgo biloba L., Platanus x hispanica Mill. ex Muenchh., Quercus rubra L., Tilia tomentosa Moench 'Brabant') and six shrub species (Acer tataricum subsp, ginnala (Maxim.) Wesm., Sambucus nigra L., Sorbaria sorbifolia (L) A.Br., Spiraea japonica L.f., Syringe meyeri C.K. Schneid. 'Palibin', Viburnum lantana L.). Significant differences were found between species in mass of total PM accumulation for two PM categories and three size fractions determined and in amount of waxes. A positive correlation was found between in-wax PM of diameter 2.5-10 microm and amount of waxes, but not between amount of waxes and amount of total PM or of any size fraction.

Asunto(s)

RESUMEN

Particulate matter (PM) is an air contaminant in urban and industrial areas that often exceeds limit values, creating serious problems due to its harmful effects on health. Planting trees and shrubs as air filters is a way to improve air quality in these areas. However,further knowledge on species effectiveness in air purification is essential This study compared four species of tree (Acer campestre L, Fraxinus excelsior L, Platanus x hispanica Mill. ex Muenchh. 'Acerifolia', Tilia cordata Mill.), three species of shrub (Forsythia x intermedia Zabel, Physocarpus opulifolius (L.) Maxim., Spiraea japonica L.), and one climber species (Hedera helix L) that are commonly cultivated along streets in Poland to capture fine, coarse and larger particles from air. Separate gravimetric analyses were performed to quantify PM deposited on surfaces and trapped in waxes. Significant differences were found between the plant species tested. The distribution of different particle size fractions differed between and within species and also between leaf surfaces and in waxes.

Asunto(s)

RESUMEN

Molecular markers have become a useful tool simplifying and speeding up breeding work. They are also helpful in the genetic analysis of complex agronomic traits. The investigations concern the use of already available SCAR markers for molecular analysis of breeding materials. The markers are the apple powdery mildew resistance gene Pl2, originating from Malus zumi, and the apple scab resistance gene Vf, from M. floribunda 821. The clone U 211 was found to be highly resistant to mildew under field conditions and transmitted a high level of resistance to the majority of its progeny. The presence of the Vf gene conferring resistance to scab was confirmed by molecular analysis. As the molecular markers for the Pl2 gene are not present in the DNA of U 211, it is probable that the clone U 211 is a new source of mildew resistance.

Asunto(s)