High phytoremediation and translocation potential of an invasive weed species (Amaranthus retroflexus) in Europe in metal-contaminated areas.

We demonstrated the metal accumulation potential of Amaranthus retorflexus, a European weed species, both in moderately and strongly metal-contaminated sites. Metal accumulation in roots, stems, and leaves were studied. We also calculated the bioaccumulation factor (BAF), and translocation factor (TF) values to quantify the metal accumulation, and translocation between plant organs. Our findings indicated that metal accumulation correlated with metal concentration; that is plant organs accumulated higher concentration of metals in the contaminated area than in the control one. We found that the concentrations of Ba, Mn, Sr and Zn were the highest in leaves, and Al, Cr, Cu, Fe and Pb in roots. High BAF value was found for Sr in all studied areas, indicating this metal's high accumulation potential of Amaranthus retorflexus. High TF values were found for Al, Ba, Cu, Fe, Mn, Sr and Zn; these metals were successfully transported to aboveground plant organs. We demonstrated that A. retroflexus, a fast-growing, rapidly spreading weed in Europe, was especially useful for heavy metal phytoremediation and phytoextraction.

Myeloid-Specific Deletion of Mcl-1 Yields Severely Neutropenic Mice That Survive and Breed in Homozygous Form.

Mouse strains with specific deficiency of given hematopoietic lineages provide invaluable tools for understanding blood cell function in health and disease. Whereas neutrophils are dominant leukocytes in humans and mice, there are no widely useful genetic models of neutrophil deficiency in mice. In this study, we show that myeloid-specific deletion of the Mcl-1 antiapoptotic protein in Lyz2 Cre/Cre Mcl1 flox/flox (Mcl1 ΔMyelo) mice leads to dramatic reduction of circulating and tissue neutrophil counts without affecting circulating lymphocyte, monocyte, or eosinophil numbers. Surprisingly, Mcl1 ΔMyelo mice appeared normally, and their survival was mostly normal both under specific pathogen-free and conventional housing conditions. Mcl1 ΔMyelo mice were also able to breed in homozygous form, making them highly useful for in vivo experimental studies. The functional relevance of neutropenia was confirmed by the complete protection of Mcl1 ΔMyelo mice from arthritis development in the K/B×N serum-transfer model and from skin inflammation in an autoantibody-induced mouse model of epidermolysis bullosa acquisita. Mcl1 ΔMyelo mice were also highly susceptible to systemic Staphylococcus aureus or Candida albicans infection, due to defective clearance of the invading pathogens. Although neutrophil-specific deletion of Mcl-1 in MRP8-CreMcl1 flox/flox (Mcl1 ΔPMN) mice also led to severe neutropenia, those mice showed an overt wasting phenotype and strongly reduced survival and breeding, limiting their use as an experimental model of neutrophil deficiency. Taken together, our results with the Mcl1 ΔMyelo mice indicate that severe neutropenia does not abrogate the viability and fertility of mice, and they provide a useful genetic mouse model for the analysis of the role of neutrophils in health and disease.

Changes in Morphometric Traits of Ground Beetles Along Urbanization Gradients.

Urbanization has a significant impact on abiotic and biotic factors in nature. We examined the morphometric characters of four carabid species (Abax parallelepipedus, Carabus scheidleri, Carabus violaceus, and Pterostichus oblongopunctatus) along urbanization gradients in and around the cities of Vienna (Austria) and Debrecen (Hungary). We found significant differences among urban, suburban, and rural areas in the parameters of antennomers, the maxillary palpus, the labial palpus, and the length of the tibia and the elytra of the carabids studied. We also found significant differences between males and females based on the parameters of antennomers, the maxillary palpus, the labial palpus, the femur, and the elytra. An interaction between urbanization and sex was found in the case of antennomers, the maxillary palpus, the labial palpus, the femur, and the elytra. Our findings suggested that in the cases of species from Carabini tribus the parameters of antennomers, the maxillary palpus, and the elytra could be useful for assessing the effects of urbanization because these morphometric characters responded sensitively to the environmental stress, whereas the most useful parameters are those of antennomers and the tibia for the species of Pterostichini tribus. Our findings also revealed that females are more sensitive to environmental stress than males.

Salinity tolerance and desalination properties of a Haematococcus lacustris strain from eastern Hungary.

Nowadays the increasing amount of saline wastewaters has given rise to various biological desalination processes, among which the application possibilities of microalgae represents a priority research area. Next to "real" aquatic species (members of phytoplankton or phytobenthon), species from ephemeral aquatic habitats or aeroterrestrial algae also could be good candidates of research studying salt tolerance or desalination ability, since salinity stress is often referred as "physiological drought" and species from ephemeral habitats can be characterized by high drought tolerance. In this study, the salinity tolerance, salt and nutrient removal ability of a Haematococcus lacustris strain from eastern Hungary were investigated. Vegetative cells showed low salt tolerance, survival was ensured by the formation of cysts up to a sodium-chloride concentration of 2,000 mg l-1. Although relatively moderate (a max. 30%) conductivity reduction and chloride removal were observed, notable (nearly 100%) nitrate and phosphate removal occurred even in the presence of 2,000 mg l-1 NaCl. Carotenoid accumulation was observed earlier and in higher extent in salt treated cultures than in drying out ones, although the amount of astaxanthin-esters was significantly higher in the cultures of drying out experiment than in the corresponding cultures of salt treatment characterized with similar chloride content. Our results suggest that algae isolates from ephemeral aquatic habitats endangered by regular drying out (exposed to special salt stress), could have notable salt tolerance and consequently successful applicability in nutrient removal processes from slightly saline wastewaters. The accumulation of valuable metabolites (such as astaxanthin) as a response to salinity stress, could enhance the economic value of the biomass.

Investigation of a Perspective Urban Tree Species, Ginkgo biloba L., by Scientific Analysis of Historical Old Specimens.

In this study, we examined over 200-year-old Ginkgo biloba L. specimens under different environmental conditions. The overall aim was to explore which factors influence their vitality and general fitness in urban environments and thus their ability to tolerate stressful habitats. In order to determine this, we used a number of different methods, including histological examinations (stomatal density and size) and physiological measurements (peroxidase enzyme activity), as well as assessing the air pollution tolerance index (APTI). The investigation of the genetic relationships between individuals was performed using flow cytometry and miRNA marker methods. The genetic tests revealed that all individuals are diploid, whereas the lus-miR168 and lus-miR408 markers indicated a kinship relation between them. These results show that the effect of different habitat characteristics can be detected through morphological and physiological responses, thus indicating relatively higher stress values for all studied individuals. A significant correlation can be found between the level of adaptability and the relatedness of the examined individuals. These results suggest that Ginkgo biloba L. is well adapted to an environment with increased stress factors and therefore suitable for use in urban areas.

Assessment of trace and macroelement accumulation in cyprinid juveniles as bioindicators of aquatic pollution: effects of diets and habitat preferences.

Juveniles of three cyprinids with various diets and habitat preferences were collected from the Szamos River (Hungary) during a period of pollution in November 2013: the herbivorous, benthic nase (Chondrostoma nasus), the benthivorous, benthic barbel (Barbus barbus), and the omnivorous, pelagic chub (Squalius cephalus). Our study aimed to assess the accumulation of these elements across species with varying diets and habitat preferences, as well as their potential role in biomonitoring efforts. The Ca, K, Mg, Na, Cd, Cr, Cu, Fe, Mn, Pb, Sr, and Zn concentration was analyzed in muscle, gills, and liver using MP-AES. The muscle and gill concentrations of Cr, Cu, Fe, and Zn increased with trophic level. At the same time, several differences were found among the trace element patterns related to habitat preferences. The trace elements, including Cd, Pb, and Zn, which exceeded threshold concentrations in the water, exhibited higher accumulations mainly in the muscle and gills of the pelagic chub. Furthermore, the elevated concentrations of trace elements in sediments (Cr, Cu, Mn) demonstrated higher accumulation in the benthic nase and barbel. Our findings show habitat preference as a key factor in juvenile bioindicator capability, advocating for the simultaneous use of pelagic and benthic juveniles to assess water and sediment pollution status.

The role of complement in Streptococcus pneumoniae-associated haemolytic uraemic syndrome.

BACKGROUND: Atypical forms of haemolytic uraemic syndrome (aHUS) include HUS caused by defects in the regulation of alternative complement pathway and HUS linked to neuraminidase-producing pathogens, such as Streptococcus pneumoniae. Increasing data support a pathogenic role of neuraminidase in the development of S. pneumoniae-associated haemolytic uraemic syndrome (SP-HUS), but the role of complement has never been clarified in detail. Therefore, we aimed to investigate whether the pathologic complement profile and genetic risk factors of aHUS are present in patients with SP-HUS. METHODS: Enrolling five patients with SP-HUS classical and alternative pathway activity, besides C3, C4, factors H, B, I and anti-factor H autoantibody levels were determined. The coding regions of CFH, CFI, CD46 (MCP), THBD, C3 and CFB genes were sequenced and the copy number of CFI, CD46, CFH and related genes were also analyzed. RESULTS: We found that in the acute phase samples of SP-HUS patients, complement components C4, C3 and activity of the classical and alternative pathways were decreased, indicating severe activation and complement consumption, but most of these alterations normalized later in remission. Three of the patients carried mutations and risk haplotypes in complement-mediated aHUS associated genes. The identified mutations include a previously published CFI variant (P50A) and two novel ones in CFH (R1149X) and THBD (T44I) genes. CONCLUSIONS: Our results suggest that severe complement dysregulation and consumption accompany the progress of invasive pneumococcal disease (IPD)-associated SP-HUS and genetic variations of complement genes may contribute to the development of this complication in a proportion of the affected patients.

Heavy metal uptake by plant parts of Populus species: a meta-analysis.

Populus species are well documented for being potentially suitable for phytoremediation purposes regarding their accumulation characteristics. However, published results are contradictory. Based on the data gathered during an extensive literature search, we aimed to assess and revise the metal accumulation potential in the root, stem, and leaf of Populus species growing in contaminated soils, with meta-analysis. We evaluated the influences of pollution level, soil pH, and exposure time on the metal uptake patterns. We found accumulations of Cd, Cr, Cu, Pb, and Zn to be significant in each plant part, while that was only moderate for Ni, and limited for Mn. By calculating the soil pollution index (PI), we observed significantly intensive, PI-independent accumulation for Cd, Cr, Cu, Ni, Pb, and Zn. A decrease in soil pH significantly increased the uptake of Mn and significantly decreased the accumulation of Pb in the stem. Metal uptake was significantly influenced by exposure time as well; Cd concentration was significantly decreased in the stem, while concentrations of Cr in the stem and leaf, and Mn in the stem were significantly increased with time. These aforementioned findings support a well-founded metal-and-growth condition-specific application of poplars in phytoremediation processes, also triggering further in-depth assessments to enhance the efficiency of relevant poplar-based technologies.

A meta-analysis on the heavy metal uptake in Amaranthus species.

Metals can accumulate in different parts of plant species in high concentrations, which gives the basis for the plant-based technology called phytoremediation. Among annual species, Amaranthus is a well-studied, potential metal accumulator genus; however, some conflicts are found among published results. Thus, we studied the metal (Cd, Cu, Fe, Ni, Pb, and Zn) accumulation potential of Amaranthus plant parts (root, stem, and leaf) by meta-analysis, furthermore, by calculation of bioaccumulation factor (BAF) values. After the extensive literature search and the calculation of relative interaction intensity (RII) values, we found significant accumulation for each metal by Amaranthus individuals growing on contaminated soils compared to plants collected from uncontaminated ones. Differences among plant parts were significant for Cu and Fe, minor for Ni, Pb, and Zn, and negligible for Cd. The BAF values indicated high accumulation in the leaf, moderate in root and stem for Cd, moderate in each plant part for Pb, and very low in each plant part for Fe, Ni, and Zn. We highlight that Amaranthus species are good prospects for metal phytoremediation projects, although, due to specific plant part-metal patterns, special attention should be paid to the harvesting practice.

Histological and Physiological Effects of Treatment of Rudbeckia hirta with Gamma Radiation.

The breeding of resistant, high-yield, decorative ornamental plant varieties may be impacted by climate change in the future. The use of radiation induces mutations in plants, thereby increasing the genetic variability of plant species. Rudbeckia hirta has long been a very popular species in urban green space management. The goal is to examine whether gamma mutation breeding can be applied to the breeding stock. Specifically, differences were measured between the M1 and M2 generations, as well as the effect of different radiation doses belonging to the same generation. Morphological measurements showed that gamma radiation has an effect on the measured parameters in several cases (larger crop size, faster development, larger number of trichomes). Physiological measurements (examination of chlorophyll and carotenoid content, POD activity, and APTI) also showed a beneficial effect of radiation, especially at higher doses (30 Gy), for both tested generations. The treatment was also effective in the case of 45 Gy, but this radiation dose resulted in lower physiological data. The measurements show that gamma radiation has an effect on the Rudbeckia hirta strain and may play a role in breeding in the future.

Assessment of the effects of urbanization on trace elements of toe bones.

Amphibians, particularly frogs and toads, are increasingly used as bioindicators of contaminant accumulation in pollution studies. We developed an analytical technique to analyse their elemental contents based on a small amount of toe bone samples. This method is environment-friendly as, unlike traditional methods, it is not necessary to kill animals during sampling. Using this technique, we explored the effects of urbanization on the elemental contents of toe bones. Bufo bufo specimens were collected from an urban and two rural ponds. The ratios of Ca and P at the ponds were: 20.5% Ca and 14.6% P at the urban pond and 30.4% and 29.6% Ca, 22.4% and 21.7% P at the rural ponds, respectively. For the other elements, the following percentage ratios were found: 0.7% B, 0.3% Mg and 0.06% Zn at the urban pond and 1.1% and 0.4% B, 0.4% Mg and 0.05% Zn at the rural ponds, respectively. Canonical discriminant analysis indicated the separation of the urban and the rural ponds based on the elemental concentrations of toe bones. Significant differences were found between the concentrations of Ca, P, Mg, B and Zn at the urban and the rural ponds (p < 0.05). Anthropogenic activity was found to have effects on the elemental contents of toe bones in the urbanized area. Our study also demonstrated that the developed method was appropriate for the elemental analysis of small samples to assess the effects of urbanization.

Genetic deficiency of Syk protects mice from autoantibody-induced arthritis.

OBJECTIVE: The Syk tyrosine kinase plays an important role in diverse functions in hematopoietic lineage cells. Although previous in vitro and pharmacologic analyses suggested Syk to be a possible player in the development of autoimmune arthritis, no in vivo genetic studies addressing that issue have yet been reported. The aim of the present study was to test whether genetic deficiency of Syk affects autoantibody-induced experimental arthritis in the K/BxN serum-transfer model. METHODS: Syk(-/-) bone marrow chimeras carrying a Syk-deficient hematopoietic system were generated by transplanting Syk(-/-) fetal liver cells into lethally irradiated wild-type recipients. After complete repopulation of the hematopoietic compartment, autoantibody-mediated arthritis was induced by injection of arthritogenic K/BxN serum. Arthritis development was monitored by macroscopic and microscopic observation of the ankle joints, micro-computed tomography of bone morphology, as well as a joint function assay. RESULTS: Genetic deficiency of Syk in the hematopoietic compartment completely blocked the development of all macroscopic and microscopic signs of arthritis. The Syk(-/-) mutation also prevented the appearance of periarticular bone erosions. Finally, Syk(-/-) bone marrow chimeras were completely protected from arthritis-induced loss of articular function. CONCLUSION: Our results indicate that Syk is critically involved in the development of all clinically relevant aspects of autoantibody-mediated K/BxN serum-transfer arthritis in experimental mice. These results provide the first in vivo genetic evidence of the role of Syk in the development of autoimmune arthritis.

Usefulness of Tree Species as Urban Health Indicators.

We used the Air Pollution Tolerance Index (APTI), the amount of PM5 and PM10, and the elemental analysis of leaves to explore the sensitivity of tree species to air pollution. We assessed the tolerance of Robinia pseudoacacia, Acer saccharinum, Tilia × europaea, Acer platanoides, Fraxinus excelsior, Betula pendula, Celtis occidentalis, and Platanus × acerifolia to the amount of dust, APTI, and the elemental concentration of leaves. Leaves were collected in Debrecen (Hungary), which has a high intensity of vehicular traffic. The highest amount of PM (both PM10 and PM5) was found on the leaves of A. saccharinum and B. pendula. Our results demonstrated that A. saccharinum was moderately tolerant, while P. acerifolia was intermediate, based on the APTI value. There was a significant difference in the parameters of APTI and the elemental concentration of leaves among species. We found that tree leaves are reliable bioindicators of air pollution in urban areas. Based on the value of APTI, A. saccharinum and P. acerifolia, and based on PM, A. saccharinum and B. pendula are recommended as pollutant-accumulator species, while other studied species with lower APTI values are useful bioindicators of air pollution. The results support landscape engineers and urban developers in finding the best tree species that are tolerant to pollution and in using those as proxies of urban environmental health.

Use of Leaves as Bioindicator to Assess Air Pollution Based on Composite Proxy Measure (APTI), Dust Amount and Elemental Concentration of Metals.

Monitoring air pollution and environmental health are crucial to ensure viable cities. We assessed the usefulness of the Air Pollution Tolerance Index (APTI) as a composite index of environmental health. Fine and coarse dust amount and elemental concentrations of Celtis occidentalis and Tilia × europaea leaves were measured in June and September at three sampling sites (urban, industrial, and rural) in Debrecen city (Hungary) to assess the usefulness of APTI. The correlation between APTI values and dust amount and elemental concentrations was also studied. Fine dust, total chlorophyll, and elemental concentrations were the most sensitive indicators of pollution. Based on the high chlorophyll and low elemental concentration of tree leaves, the rural site was the least disturbed by anthropogenic activities, as expected. We demonstrated that fine and coarse dust amount and elemental concentrations of urban tree leaves are especially useful for urban air quality monitoring. Correlations between APTI and other measured parameters were also found. Both C. occidentalis and T. europaea were sensitive to air pollution based on their APTI values. Thus, the APTI of tree leaves is an especially useful proxy measure of air pollution, as well as environmental health.

Pollution Assessment Based on Element Concentration of Tree Leaves and Topsoil in Ayutthaya Province, Thailand.

Atmospheric aerosol particles containing heavy metal contaminants deposit on the surface of plant leaves and the topsoil. Our aim was to reveal the pollution along an industrial-urban-rural gradient (IURG) in the central provinces of Thailand. Leaf samples from Ficus religiosa and Mimusops elengi were collected along with topsoil samples under the selected trees. Al, Ba, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn concentrations were determined by ICP-OES in soil and plant samples. Soils were not polluted according to the critical value; furthermore, the elemental composition did not differ among the sampling sites of the IURG. The rural site was also polluted due to heavy amounts of untreated wastewater of the adjacent Chao Phraya River. Bioaccumulation factors of Ba, Cu, and Mn was higher than 1, suggesting active accumulation of these elements in plant tissue. Our findings proved that the deposition of air pollutants and the resistance to air pollutants in the case of plant leaves were different and that humus materials of the soils had relevant role in bioaccumulation of Al, Ba, and Cu. At the same time, the geochemical background, the source of pollution, and the local plant species greatly influence the metal content of any given environmental compartment.

The Effect of Urbanization on Trace Element Concentration and Symmetry of Woodlice (Armadillidium vulgare Latreille, 1804).

Woodlice are top consumers of a three-trophic system (soil, leaf litter, woodlice), and they are closely related to pollutant absorbing surfaces such as soil, leaf litter, and organic matter. We studied the effects of urbanization on trace element concentrations and fluctuating asymmetry of Armadillidium vulgare (Crustacea: Isopoda) individuals in and around Debrecen city, Hungary. Along an urbanization gradient (urban, suburban, and rural areas), trace element concentrations (Ba, Cu, Fe, Mn, Pb, and Zn) of woodlice and bioconcentration factor (BCF) were analyzed. Asymmetry was also measured in metric traits of woodlice: the length of three segments of antennae, the body length, and the width of the 3rd segment of pereon. We found significant differences in Ba and Cu concentration of A. vulgare individuals along the urbanization gradient. The highest Cu concentration was found in woodlice from the urban area and the highest Ba concentration was found in the individuals from the rural area. The Ba concentration was higher in females than in males. The BCF values of Cu indicated that A. vulgare accumulated this element from soil and leaf litter. There was no significant difference in symmetry of the bilateral traits of woodlice along the urbanization gradient based on FA levels. Our results showed that the urbanization had remarkable effect on the Ba and Cu concentration of woodlice which were originated from traffic pollution. At the same time, the anthropogenic activities did not affect the symmetry of the tested traits of A. vulgare individuals.

Pollution intensity-dependent metal accumulation in ground beetles: a meta-analysis.

Survival of organisms in polluted habitats is a key factor regarding their long-term population persistence. To avoid harmful physiological effects of pollutants' accumulation in organisms, decontamination and excretion could be effective mechanisms. Among invertebrates, ground beetles are reliable indicators of environmental pollution. Published results, however, are inconsistent, as some studies showed effective decontamination and excretion of pollutants, while others demonstrated severe toxic symptoms due to extreme accumulation. Using ground beetles as model organisms, we tested our pollution intensity-dependent disposal hypothesis for five pollutants (Cd, Cu, Mn, Pb, and Zn) among four soil pollution intensity levels (low, moderate, high, and extreme) by categorical meta-analysis on published data. According to our hypothesis, decontamination and excretion of pollutants in ground beetles are effective in lowly or moderately polluted habitats, while disposal is ineffective in highly or extremely polluted ones, contributing to intense accumulation of pollutants in ground beetles. In accordance with the hypothesis, we found that in an extremely polluted habitat, accumulation of Cd and Pb in ground beetles was significantly higher than in lowly polluted ones. These findings may suggest the entomoremediation potential of ground beetles in an extremely polluted environment.

Hematopoietic or Osteoclast-Specific Deletion of Syk Leads to Increased Bone Mass in Experimental Mice.

Syk is a non-receptor tyrosine kinase critically involved in signaling by various immunoreceptors including B-cell-receptors and activating Fc-receptors. We have previously shown that Syk also mediates immunoreceptor-like signals required for the in vitro development and function of osteoclasts. However, the perinatal lethality of Syk-/- mice precluded the analysis of the role of Syk in in vivo bone metabolism. To overcome that problem, we generated mice with osteoclast-specific (SykΔOC ) or hematopoietic (SykΔHaemo ) Syk deficiency by conditional deletion of Syk using Cre recombinase expressed under the control of the Ctsk or Vav1 promoter, respectively. Micro-CT analysis revealed increased bone trabecular density in both SykΔOC and SykΔHaemo mice, although hematopoietic Syk deficiency caused a more severe phenotype than osteoclast-specific Syk deficiency. Osteoclast-specific Syk deficiency reduced, whereas hematopoietic Syk deficiency completely blocked in vitro development of osteoclasts. Both interventions inhibited the resorptive activity of osteoclasts and osteoclast-specific gene expression. Kinetic analysis of Syk protein levels, Cre expression and the genomic deletion of the Sykflox allele revealed complete and early deletion of Syk from SykΔHaemo osteoclasts whereas Syk was incompletely deleted at a later stage of osteoclast development from SykΔOC cultures. Those results provide an explanation for the in vivo and in vitro difference between the SykΔOC and SykΔHaemo mutant strains and suggest late activation of, and incomplete target gene deletion upon, osteoclast-specific Cre expression driven by the Ctsk promoter. Taken together, our results indicate that Syk plays an indispensable role in osteoclast-mediated in vivo bone resorption and suggest that Syk-specific inhibitors may provide therapeutic benefit in inflammatory and other diseases characterized by excessive osteoclast-mediated bone resorption.

Phytoextraction with Salix viminalis in a moderately to strongly contaminated area.

We tested the suitability of Salix viminalis for phytoextraction with the analysis of selected elements in soil, root, and leaf, and by visual tree condition assessment in an area with varying levels of contamination. Bioconcentration factor (BCF) and translocation factor (TF) were used to assess the phytoextraction potential of willows. The middle part of the study area was strongly contaminated, while the northern and southern parts were moderately contaminated. We found increasing element concentrations toward deeper layers. Mean concentrations of elements in roots were similar among the three parts, while in leaves the highest concentrations were found in the strongly contaminated part of the study area. Tree condition scores were the lowest in the strongly contaminated part of the study area, which was caused by Al, Ca, K, Mg, Ni, Sr, and Zn concentration. These elements induced leaf disease and leaf feeders. The highest BCF values were found for Cu, Fe, Mn, and Zn in root, and for Cd and Zn in leaves, indicating that S. viminalis had high accumulation potential of these elements. Furthermore, TF values were high for Cd, Mn, Sr, and Zn. Our results also demonstrated that soil element composition has major influence on the condition of S. viminalis individuals. Furthermore, visual condition assessment was found to be a useful tool to assess the phytoextraction potential of trees.

Heavy metal uptake by plant parts of willow species: A meta-analysis.

Previous studies on phytoremediation reported contradictory or inconsistent results on the Cd, Pb, and Zn accumulation in and among plant parts of willow (Salix) species. We hypothesized that metals could accumulate in all plant organs in different concentrations and the metal accumulation in tissues would be increased with exposure time. Furthermore, we analysed the effect of soil pH on metal accumulation, and the correlation between metals. We evaluated published information on Cd, Pb, and Zn accumulation in root, stem, twig, and leaf of willow species using meta-analysis. Results showed that all parts of willow species accumulated significantly more Cd, Pb, and Zn in contaminated soils than in uncontaminated soils. However, the metal accumulation was significantly different among plant parts. We concluded that willow species were proven to be prosperous accumulators of Cd (twigs and leaves), Pb (roots and twigs) and Zn (twigs). We found that Cd accumulation rate in stems is higher in soils with lower pH. Significant positive correlation was found between the accumulations of Cd and Zn in stems. Accumulation rates of Cd (both in leaves and twigs) and Zn (in twigs) were increased significantly with exposure time and the accumulation was successful for at least 3 years.