Pollen of Betula pendula, Ostrya carpinifolia and Carpinus betulus was exposed in vitro to two levels of NO2 (about 0.034 and 0.067 ppm) – both below current atmospheric hour-limit value acceptable for human health protection in Europe (0.11 ppm for NO2). Experiments were performed under artificial solar light with temperature and relative humidity continuously monitored. The viability, germination and total soluble proteins of all the pollen samples exposed to NO2 decreased significantly when compared with the non-exposed. The polypeptide profiles of all the pollen samples showed bands between 15 and 70 kDa and the exposure to NO2 did not produce any detectable changes in these profiles. However, the immunodetection assays indicated higher IgE recognition by patient sera sensitized to the pollen extracts from all exposed samples in comparison to the non-exposed samples. The common reactive bands to the three pollen samples correspond to 58 and 17 kDa proteins.

Amending contaminated soils with organic wastes can influence trace element mobility and toxicity. Soluble concentrations of metals and arsenic were measured in pore water and aqueous soil extracts following the amendment of a heavily contaminated mine soil with compost and biochar (10% v:v) in a pot experiment. Speciation modelling and toxicity assays (Vibrio fischeri luminescence inhibition and Lolium perenne germination) were performed to discriminate mechanisms controlling metal mobility and assess toxicity risk thereafter. Biochar reduced free metal concentrations furthest but dissolved organic carbon primarily controlled metal mobility after compost amendment. Individually, both amendments induced considerable solubilisation of arsenic to pore water (>2500 μg l−1) related to pH and soluble phosphate but combining amendments most effectively reduced toxicity due to simultaneous reductions in extractable metals and increases in soluble nutrients (P). Thus the measure–monitor-model approach taken determined that combining the amendments was most effective at mitigating attendant toxicity risk.

In the framework of an ecological risk assessment of seaport sediments for terrestrial ecosystems when deposited in quarries, we simulated the “ageing” of sediments exposed to rain. This experiment highlighted an inflection point at the solid/liquid ratio 1/25, after which the extraction of pollutants increases moderately. The raw sediments studied inhibited the germination of Lolium perenne and Armeria maritima (a halophytic species) seeds. Furthermore, they affected the early development of L.perenne. The same sediments, leached at a ratio of 1/25, presented a reduction of acute (germination) and chronic (growth) phytotoxicity. The bioconcentration factors of the metals studied decreased with the leached sediment, except for Cu which was still clearly identified in root parts. Thus rotary leaching tests and phytotoxicity bioassays can be used to provide an initial assessment of the ability of plants, particularly halophytes, to colonize deposits of dredged seaport sediments.

Seed priming effects on Trifolium repens were analysed both in Petri dishes and in two soils (one unpolluted soil and a soil polluted with Cd and Zn). Priming treatments were performed with gibberellic acid 0.1 mM at 22 °C during 12 h or with polyethylene glycol (−6.7 MPa) at 10 °C during 72 h. Both priming treatments increased the germination speed and the final germination percentages in the presence of 100 μM CdCl₂or 1 mM ZnSO₄. Flow cytometry analysis demonstrated that the positive effect of priming was not related with any advancement of the cell cycle in embryos. Seed imbibition occurred faster for primed seeds than for control seeds. X-ray and electronic microscopy analysis suggested that circular depressions on the seed coat, in addition to tissue detachments inside the seed, could be linked to the higher rate of imbibition. Priming treatments had no significant impact on the behaviour of seedlings cultivated on non-polluted soil while they improved seedling emergence and growth on polluted soil. The two priming treatments reduced Zn accumulation. Priming with gibberellic acid increased Cd accumulation by young seedlings while priming with polyethylene glycol reduced it. Priming improved the light phase of photosynthesis and strengthened the antioxidant system of stressed seedlings. Optimal priming treatment may thus be recommended as efficient tools to facilitate revegetation of former mining area.

Municipal solid wastes (MSW) are unavoidable sources of environmental pollution. Improper disposal of municipal waste results in the leaching of toxic metals and organic chemicals, which can contaminate the surface and ground water leading to serious health hazard. In this study, the toxic effects of the leachate prepared from municipal solid waste samples were examined in root meristem cells of barley (Hordeum vulgare L.) at various stages of cell cycle, i.e., G₁, S, and G₂. Seeds of barley were exposed to 2.5, 5, and 10 % of leachates in soil and aqueous media in 48 h at different cell cycle stages. The physicochemical data of the present study revealed that municipal solid waste leachate contains high amount of heavy metals, which significantly affected growth and physiological activities of barley. Significant inhibition in hypocotyl length, germination, and mitotic index were observed at all concentration of leachate treatment. Induction of chromosomal aberrations (CA’s) and micronuclei (MN) formation were also observed with different concentrations of leachate treatment at 7, 17, and 27 h of presoaking durations, which falls in G₁, S, and G₂phase of the cell cycle, respectively. Also, exposure of leachate at S phase of the cell cycle had significant effects in barley through chromosomal aberration and micronuclei formation.

Deposition of cement dust on soils and plant surfaces is known to affect plant growth and the species composition of plant communities, but little is known about its effects (and those of its pH and constituents) on germination. Therefore, the aim of this study was to assess the toxicity of an aqueous cement extract, constituents of the extract and pH on the germination of seeds of a selected species, Medicago sativa. First, the effects of the extract were tested in assays with concentrations and exposure durations ranging from 0 to 1.0 g/mL and 4 to 96 h, respectively. At 0.8 g/mL, the extract strongly inhibited germination; a 4-h exposure reduced the germination rate, from 77 ± 1.8 to 50 ± 2.6 % (mean ± SE), while 8-h exposure completely inhibited it. Further, treatment at this concentration killed the non-germinating seeds, thus the inhibition was due to toxic effects. Neither the pH of the extract nor the concentration of its main soluble elements separately (K, Ca, S, Na, or Cr) caused the toxicity since germination rates were not significantly reduced when these variables were tested individually. However, a mixture of the elements in solution reduced germination rates, suggesting that they have adverse synergistic effects.

Ostrya spp. and Carpinus spp. pollen was in vitro exposed to three atmospheric pollutants: CO, O₃ and SO₂. Two levels of each pollutant were used, and the first level corresponds to a concentration about the atmospheric hour-limit value acceptable for human health protection in Europe and the second level to about the triple of the first level. Experiments were done under artificial solar light with temperature and relative humidity controlled. The viability of the exposed pollen samples showed a significant decrease. Also, the germination percentage showed a significant decrease in both exposed pollens, and the effect was most pronounced for SO₂, followed by O₃ and CO. A general decreasing trend in the total soluble protein content of the exposed pollen samples when compared with the control was observed, but it was only statistically significant for the Ostrya spp pollen. The results showed marked effects were observed on the Ostrya spp. and Carpinus spp. pollen when exposed to air pollutant levels that can be considered safe for human health protection.

Ionic liquids (ILs) are called "green" solvents, which are due to their unique physicochemical properties and potential applications in various areas. However, the toxicity of ILs has attracted increasing attention from scientific researchers. The present paper studied the toxic effects of 1-octyl-3-methylimidazolium hexafluorophosphate ([C₈mim]PF₆) on wheat seedlings at 0, 1, 2, 4, 6, and 8 mg l⁻¹on days 7, 10 and 13. The present results showed that the growth of wheat seedlings was seriously inhibited when the concentration was higher than 2 mg l⁻¹and the inhibitory effect enhanced with increasing concentration and time. The EC₅₀values for germination, shoot length, root length and dry weight were 11.104, 5.187, 4.380 and 6.292 mg l⁻¹, respectively. [C₈mim]PF₆could cause an increase in the production of ROS, which led to the oxidative damage and lipid peroxidation. Furthermore, these toxic effects on wheat seedlings were irreversible.

The paper describes the fieldwork at the Italian test site of the abandoned mine of sphalerite and galena in Ingurtosu (Sardinia), with the aim to assess the applicability of a “toolbox” to establish the optimized techniques for remediation of soils contaminated by mining activities. A preliminary characterization—including (hydro)geochemistry, heavy metal concentration and their mobility in soil, bioprospecting for microbiology and botany—provided a data set for the development of a toolbox to deliver a microbially assisted phytoremediation process. Euphorbia pithyusa was selected as an endemic pioneer plant to be associated with a bacterial consortium, established with ten selected native strains, including metal-tolerant bacteria and producers of plant growth factors. The toolbox was firstly assessed in a greenhouse pot experiment. A positive effect of bacterial inoculum on E. pithyusa germination and total plant survival was observed. E. pithyusa showed to be a well-performing metallophyte species, and only inoculated soil retained a microbial activity with a high functional diversity, expanding metabolic affinity also towards root exudates. These results supported the decision to proceed with a field trial, investigating different treatments used singly or in combination: bioaugmentation with bacterial consortia, mycorrhizal fungi and a commercial mineral amendment. Microbial activity in soil, plant physiological parameters and heavy metal content in plants and in soil were monitored. Five months after the beginning, an early assessment of the toolbox under field conditions was carried out. Despite the cold season (October–March), results suggested the following: (1) the field setup as well as the experimental design proved to be effective; (2) plant survival was satisfactory; (3) soil quality was increased and bioaugmentation improved microbial activity, expanding the metabolic competences towards plant interaction (root exudates); and (4) multivariate analysis supported the data provided that the proposed toolbox can be established and the field trial can be carried forward.

In the salt marshes of the joint estuary of Tinto and Odiel rivers (SW Spain), one of the most polluted areas by heavy metals in the world, Spartina densiflora grows on sediments with high concentrations of heavy metals. Furthermore, this species has shown to be useful for phytoremediation. The total bacterial population of the rhizosphere of S. densiflora grown in two estuaries with different levels of metal contamination was analyzed by PCR denaturing gradient gel electrophoresis. Results suggested that soil contamination influences bacterial population in a greater extent than the presence of the plant. Twenty-two different cultivable bacterial strains were isolated from the rhizosphere of S. densiflora grown in the Tinto river estuary. Seventy percent of the strains showed one or more plant growth-promoting (PGP) properties, including phosphate solubilization and siderophores or indolacetic acid production, besides a high resistance towards Cu. A bacterial consortium with PGP properties and very high multiresistance to heavy metals, composed by Aeromonas aquariorum SDT13, Pseudomonas composti SDT3, and Bacillus sp. SDT14, was selected for further experiments. This consortium was able to two-fold increase seed germination and to protect seeds against fungal contamination, suggesting that it could facilitate the establishment of the plant in polluted estuaries.