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  • 1.
    Bergqvist, Claes
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Arsenic accumulation and speciation in plants from different habitats2012In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 27, no 3, p. 615-622Article in journal (Refereed)
    Abstract [en]

    Understanding As accumulation in plants is necessary in order to alleviate problems with As in the environment and to improve sustainable As phytotechnologies. To find suitable candidates for phytoremediation purposes and to investigate specific accumulation patterns due to growth habitat and plant groups, As accumulation in 124 plant species collected from different habitats and speciation in 6 of these plant species, was determined. The data show that submerged plants have a higher accumulation than emergent and terrestrial plants. The As concentration in terrestrial and emergent plants were correlated with the [As](soil), while the accumulation factor correlated negatively with [As](soil). Gymnosperms had a high [As](shoot):[As](root) ratio. The inorganic As species, arsenate and arsenite were found in plants from all habitats and methylarsonic acid (MMA) in all but one plant species. Arsenate predominated in submerged plants. The results suggest that the habitat and the [As](soil) have a strong influence on the As accumulation in plants and that submerged plants and/or gymnosperms might be suitable for phytoremediation of As.

  • 2.
    Bergqvist, Claes
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Herbert, Roger
    Department of Earth Sciences, Uppsala University.
    Persson, Ingmar
    Department of Inorganic and Physical Chemistry, Swedish University of Agricultural Sciences.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Accumulation and speciation of arsenic in vegetables cultivated in soils with various As availabilityManuscript (preprint) (Other academic)
    Abstract [en]

    The toxicity of arsenic (As) in the environment is controlled by its concentration, availability and speciation. The aims of the study were to evaluate the accumulation and speciation of As in three vegetables (carrot, lettuce, spinach) cultivated in both contaminated and natural soils with various As concentrations and to estimate the concomitant health risks associated with the consumption of the vegetables. Arsenic concentration and speciation in plant tissues and soils was analysed by HPLC, AAS and X-ray absorption near-edge structure (XANES) spectroscopy. To estimate the plants influence in the rhizosphere, organic acids in lettuce root exudates were analysed by ion chromatography. The results showed that the As accumulation was higher in plants cultivated in soil with higher As extractability. Arsenate predominated in the soils, rhizosphere and root exudates of lettuce. Succinic acid was the major organic acid in lettuce root exudates. Arsenite was the predominating As species in the shoots of healthy looking plants. In plants showing signs of phytotoxicity, arsenate was predominating. Ingestion of the tested vegetables may result in an intake of elevated levels of As.

  • 3.
    Bergqvist, Claes
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Herbert, Roger
    Persson, Ingmar
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Plants influence on arsenic availability and speciation in the rhizosphere, roots and shoots of three different vegetables2014In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 184, p. 540-546Article in journal (Refereed)
    Abstract [en]

    The toxicity of arsenic (As) in the environment is controlled by its concentration, availability and speciation. The aims of the study were to evaluate the accumulation and speciation of As in carrot, lettuce and spinach cultivated in soils with various As concentrations and to estimate the concomitant health risks associated with the consumption of the vegetables. Arsenic concentration and speciation in plant tissues and soils was analysed by HPLC, AAS and XANES spectroscopy. To estimate the plants influence in the rhizosphere, organic acids in lettuce root exudates were analysed by ion chromatography. The results showed that the As accumulation was higher in plants cultivated in soil with higher As extractability. Arsenate predominated in the soils, rhizosphere and root exudates of lettuce. Succinic acid was the major organic acid in lettuce root exudates. Ingestion of the tested vegetables may result in an intake of elevated levels of inorganic As.

  • 4. Faltmarsch, Rasmus
    et al.
    Osterholm, Peter
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Astrom, Mats
    Metal concentrations in oats (Avena sativa L.) grown on acid sulphate soils2009In: Agricultural and Food Science, ISSN 1459-6067, E-ISSN 1795-1895, Vol. 18, no 1, p. 45-56Article in journal (Refereed)
    Abstract [en]

    The aim of the study was to investigate the impact of soil chemistry on the concentrations of Co, Ni, Zn, Mn, Cu and Fe in oats (Avena saliva L. cv. Fiia) grown on Finnish acid sulphate (AS) soils with varying geochemical characteristics. Twenty two soil profiles, which were sampled to a depth of 1 m (five 20 cm section splits), and 26 composite oat grain samples were collected on a total of five fields. The concentrations of Co, Ni, Zn and Mn in the grains were correlated with the NH4Ac-EDTA-extractable concentrations in the soils. However, as these four chalcophilic metals are in general easily lost to drains and not retained as a large pool in the soil in easily-extractable form, also the concentrations in the oats were not in general elevated as compared with average values on other soils. On one of the fields, however, the Co and Ni concentrations in the soil, and thus also in the oats, were clearly elevated. Copper and Fe displayed no correlation between the soil and oat concentrations, indicating that the plant-uptake mechanisms are much more important than variations in geochemistry. It was suggested that the NH4Ac-EDTA solution was not efficient in extracting Fe and Cu, which shows that these metals are bound in relatively immobile oxyhydroxides.

  • 5. Forsberg, Lovisa
    et al.
    Kleja, Dan
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Ledin, Stig
    Effects of sewage sludge on solution chemistry and plant uptake of Cu in sulphide mine tailings at different weathering stages2009In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 24, no 3, p. 475-482Article in journal (Refereed)
    Abstract [en]

    This climate chamber experiment examines the effects of sewage sludge (SS) on sulphide mine tailings from the Aitik Cu mine in northern Sweden. The effects of SS were determined from Cu in solution and Cu uptake and growth of plants on tailings showing 3 different degrees of weathering. Possible relationships between Cu content in plants and Cu in solution measured in tailings (total dissolved Cu and free Cu) were also evaluated. Red fescue (Festuca rubra) was grown for 6 weeks in pots of the different tailings treated with SS or NPK fertiliser. Soil solution was sampled with Rhizon tension lysimeters and analysed for pH, dissolved organic C (DOC), free Cu, total dissolved Cu and SO42-. The effects of SS on Cu in solution and plants depended on the degree of weathering. In tailings with a low degree of sulphide oxidation, SS application resulted in increased solubility and shoot accumulation of Cu compared with NPK-treated tailings, probably due to DOC forming soluble complexes with Cu. Sewage sludge also seemed to promote translocation of Cu to shoots in those tailings. In highly weathered tailings, lower contents of total dissolved Cu and free Cu in solution and lower Cu levels in shoots were found in SS-treated samples than in NPK-treated. In the moderately weathered tailings, Cu concentrations in solutions were generally similar between treatments, but lower contents of Cu were found in shoots and roots of the fescue grown in the SS-treatment. Irrespective of degree of weathering and treatment, both free Cu and total dissolved Cu concentration in tailings correlated strongly with Cu levels found in fescue shoots.

  • 6.
    Fritioff, Åsa
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Fate of Cadmium in Elodea canadensis2007In: Journal of Experimental Botany, ISSN 0022-0957, E-ISSN 1460-2431, Vol. 67, no 2, p. 365-375Article in journal (Refereed)
    Abstract [en]

    Elodea canadensis is a submersed macrophytes, widely distributed in stormwater treatment ponds and able to remove heavy metals from water. This study examines the Cd uptake, translocation, and efflux patterns in Elodea. Several experiments were set up in a climate chamber. To study the root and shoot Cd uptake, living and dead roots and shoots were treated with 109Cd in one- and two-compartment systems. Furthermore, to examine Cd translocation and distribution, either roots or shoots were treated with 109Cd. Finally, the efflux of Cd from roots and shoots, respectively, to the external solution was studied after loading whole plants with 109Cd. Results from the two compartment studies show that Cd is accumulated via direct uptake by both roots and shoots of Elodea. The Cd accumulation proved not to be metabolically dependent in Elodea, and the apoplastic uptake in particular was decreased by Cd pretreatment. In one week, up to 23% of the root uptake was translocated to the shoots, while about 2% of the Cd accumulated by shoots was translocated to the roots. Thus, slight dispersion of Cd is possible, while metal immobilization will not be directly mediated via the Elodea plant. The efflux experiment proved that both shoots of dead plants and roots of living plants had a faster efflux than did shoots of living plants. This information is relevant for an understanding of the fate of Cd in stormwater treatment ponds with Elodea

    .

  • 7.
    Fritioff, Åsa
    et al.
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Fate of cadmium in Elodea canadensis2007In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Chemosphere, Vol. 67, no 2, p. 365-375Article in journal (Other (popular science, discussion, etc.))
    Abstract [en]

    Elodea canadensis is a submersed macrophytes, widely distributed in stormwater treatment ponds and able to remove heavy metals

    from water. This study examines the Cd uptake, translocation, and efflux patterns in Elodea. Several experiments were set up in a climate

    chamber. To study the root and shoot Cd uptake, living and dead roots and shoots were treated with 109Cd in one- and two-compartment

    systems. Furthermore, to examine Cd translocation and distribution, either roots or shoots were treated with 109Cd. Finally, the efflux of

    Cd from roots and shoots, respectively, to the external solution was studied after loading whole plants with 109Cd. Results from the two

    compartment studies show that Cd is accumulated via direct uptake by both roots and shoots of Elodea. The Cd accumulation proved

    not to be metabolically dependent in Elodea, and the apoplastic uptake in particular was decreased by Cd pretreatment. In one week, up

    to 23% of the root uptake was translocated to the shoots, while about 2% of the Cd accumulated by shoots was translocated to the roots.

    Thus, slight dispersion of Cd is possible, while metal immobilization will not be directly mediated via the Elodea plant. The efflux experiment

    proved that both shoots of dead plants and roots of living plants had a faster efflux than did shoots of living plants. This information

    is relevant for an understanding of the fate of Cd in stormwater treatment ponds with Elodea.

  • 8.
    Fritioff, Åsa
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Uptake and distribution of Zn, Cu, Cd, and Pb in an aquatic plant Potamogeton natans2006In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 63, no 2, p. 220-227Article in journal (Refereed)
    Abstract [en]

    A better understanding of metal uptake and translocation by aquatic plants can be used to enhance the performance of constructed wetland systems for stormwater treatment. Specifically, this study examines whether the uptake of Zn, Cu, Cd, and Pb by Potamogeton natans is via the leaves, stems, or roots, and whether there is translocation from organs of uptake to other plant parts. Competition between the metals at uptake and at the level of the cell wall-bound part of the metals accumulated in stem and leaf tissue was also examined. The results show that Zn, Cu, Cd, and Pb were taken up by the leaves, stems, and roots, with the highest accumulation found in the roots. At the elevated metal concentrations common in stormwater the uptake of Cu, but not of Zn, Cd, or Pb, by the roots was somewhat limited at uptake due to competition with other metals. Between 24% and 59% of the metal content was bound to the cell walls of the plant. Except in the case of Pb, the cell wall-bound fraction was generally smaller in stems than in leaves. No translocation of the metals to other parts of the plant was found, except for Cd which was translocated from leaf to stem and vice versa. Dispersion of metals from sediment to water through P. natans is therefore unlikely.

  • 9.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Växter i askvägbeläggning2007Report (Other academic)
  • 10.
    Greger, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bergqvist, Claes
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Sandhi, Arifin
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Royal Institute of Technology, Sweden.
    Landberg, Tommy
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Influence of silicon on arsenic uptake and toxicity in lettuce2015In: Journal of Applied Botany and Food Quality / Angewandte Botanik, ISSN 1613-9216, E-ISSN 1439-040X, Vol. 88, p. 234-240Article in journal (Refereed)
    Abstract [en]

    Lettuce grown in soil is found to contain high concentrations of arsenic (As). This paper investigates the uptake and speciation of As in lettuce as well as the influence of silicon (Si) on As uptake, since Si may decrease it. Lettuce plants were cultivated in nutrient solution containing arsenite or arsenate with or without silicate. The uptake and distribution of As between roots and shoots, As accumulation in cell walls, As speciation, and toxic effects on growth were analysed. Results indicate that arsenite was more toxic to lettuce than was arsenate. Silicate decreased arsenate toxicity but had little effect on arsenite toxicity. In contrast, Si decreased arsenite uptake more than arsenate uptake. The concentration of arsenate was higher than that of arsenite in the plants independent of the As species added. When arsenate was added, the As concentration in shoots was half of that in the roots and this distribution did not change with Si addition. When arsenite was added, approximately 10% of As was found in the shoots and 90% in the roots; this pattern changed in the presence of Si, and As became evenly distributed in the plant. In both roots and shoots, approximately 40% of the As was found in the cell wall fraction; when arsenite was added, the presence of Si increased this fraction to 47%, but only in the shoots. The extraction efficiency when analysing the As species was lower in shoots than in roots, especially in the presence of arsenite and Si. The opposite was found for As concentration in pellets after extraction. This indicated variation in the binding strength of arsenite and arsenate between roots and shoots and between Si- and non-Si-treated plants.

  • 11.
    Greger, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bergqvist, Claes
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Sandhi, Arifin
    Dept. of Land and Water Resources Engineering, Royal Institute of Technology.
    Landberg, Tommy
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Influence of silicon on arsenic uptake and toxicity in lettuceManuscript (preprint) (Other academic)
    Abstract [en]

    Lettuce grown in soil is found to contain high concentration of the toxic element arsenic (As). The aim was therefore to investigate uptake and speciation of As in lettuce as well as the influence of silicon (Si) on As uptake, since Si may diminish the As uptake. Plants were cultivated in nutrient solution containing arsenite or arsenate with or without silicate. Uptake and distribution of As between roots and shoots, As accumulation in cell walls, As speciation and toxic effect on biomass were analysed. Results show that arsenite was more toxic to lettuce than arsenate. Silicate decreased the toxicity to arsenate but very little of the arsenite toxicity was changed by Si. On the other hand, Si diminished the arsenite uptake more than the arsenate uptake. There was higher concentration of arsenate than of arsenite in the plant independent which As species added. When arsenate was added, the As concentration in shoot was half of that in the root and this distribution did not change with Si addition. When arsenite was added, about 10% of As was found in the shoots and 90% in the roots, but changed in the presence of Si to be evenly distributed in the plant. In both roots and shoot, about 40% of the As was found in the cell wall fraction, and only in the shoot when arsenite was added, Si increased this fraction to 47%. The extraction efficiency when analysing the As-species was lower in shoot than in roots, especially in the presence of arsenite and Si. The opposite was found for the As concentration in pellets after extraction. This pointed towards variations in the strength of binding of arsenite and arsenate between roots and shoots and between Si and non-Si treated plants.

  • 12.
    Greger, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Dabrowska, Beata
    Stockholm University, Faculty of Science, Department of Botany.
    INFLUENCE OF NUTRIENT LEVEL ON METHYLMERCURY CONTENT IN WATER SPINACH2010In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 29, no 8, p. 1735-1739Article in journal (Refereed)
    Abstract [en]

    Widely consumed vegetables are often cultivated in sewage waters with high nutrient levels. They can contain high levels of methylmercury (MeHg), because they can form MeHg from inorganic Hg in their young shoots. We determined whether the MeHg uptake and the MeHg formation in the shoots of water spinach (Ipomoea aquatica) were affected by the presence of a high nutrient level in the growth medium. Water spinach shoots were rooted and pretreated in growth medium containing 7% (low) or 70% (high) Hoagland nutrient solution; thereafter, the plants were treated with either 0.02 mu M MeHg or 0.2 mu M HgCl2 for 3 d. Half the plants were then analyzed for total Hg and MeHg. The remaining plants were transferred to mercury-free medium with low or high nutrient levels and posttreated for 3 clays before analysis of total Hg and MeHg in order to measure MeHg formation in the absence of external Hg. The results indicate that nutrient level did not influence MeHg uptake, but that a high nutrient level reduced the distribution of MeHg to the shoots 2.7-fold versus low nutrient level. After treatment with HgCl2, MeHg was found in roots and new shoots but not in old shoots. The MeHg:total-Hg ratio was higher in new shoots than in roots, being 13 times higher at high versus low nutrient levels. Thus, MeHg formation was the same in new shoots independent of inorganic Hg concentration, since the total Hg level decreased at a high nutrient level.

  • 13.
    Greger, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kabir, Ahmad H.
    Landberg, Tommy
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Maity, Pooja J.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Lindberg, Sylvia
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Silicate reduces cadmium uptake into cells of wheat2016In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 211, p. 90-97Article in journal (Refereed)
    Abstract [en]

    Cadmium (Cd) is a health threat all over the world and high Cd content in wheat causes high Cd intake. Silicon (Si) decreases cadmium content in wheat grains and shoot. This work investigates whether and how silicate (Si) influences cadmium (Cd) uptake at the cellular level in wheat. Wheat seedlings were grown in the presence or absence of Si with or without Cd. Cadmium, Si, and iron (Fe) accumulation in roots and shoots was analysed. Leaf protoplasts from plants grown without Cd were investigated for Cd uptake in the presence or absence of Si using the fluorescent dye, Leadmium Green AM. Roots and shoots of plants subjected to all four treatments were investigated regarding the expression of genes involved in the Cd uptake across the plasma membrane (i.e. LCT1) and efflux of Cd into apoplasm or vacuole from the cytosol (i.e. HMA2). In addition, phytochelatin (PC) content and PC gene (PCS1) expression were analysed. Expression of iron and metal transporter genes (IRT1 and NRAMP1) were also analysed. Results indicated that Si reduced Cd accumulation in plants, especially in shoot. Si reduced Cd transport into the cytoplasm when Si was added both directly during the uptake measurements and to the growth medium. Silicate downregulated LCT1 and HMA2 and upregulated PCS1. In addition, Si enhanced PC formation when Cd was present. The IRT1 gene, which was downregulated by Cd was upregulated by Si in root and shoot facilitating Fe transport in wheat. NRAMP1 was similarly expressed, though the effect was limited to roots. This work is the first to show how Si influences Cd uptake on the cellular level.

  • 14.
    Greger, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Landberg, Tommy
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Influence of Si on Cd in wheat.2008In: Scientific workshop on Contaminants and nutrients: availability, accumulation/exclusion and plant-microbia-soil interactions, COST Action 859 workshop, Smolenice, May 2008, 2008, p. 1-Conference paper (Other (popular science, discussion, etc.))
  • 15.
    Greger, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Landberg, Tommy
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Novel Field Data on Phytoextraction: Pre-Cultivation With Salix Reduces Cadmium in Wheat Grains2015In: International journal of phytoremediation, ISSN 1522-6514, E-ISSN 1549-7879, Vol. 17, no 10, p. 917-924Article in journal (Refereed)
    Abstract [en]

    Cadmium (Cd) is a health hazard, and up to 43% of human Cd intake comes from wheat products, since Cd accumulates in wheat grains. Salix spp. are high-accumulators of Cd and is suggested for Cd phytoextraction from agricultural soils. We demonstrate, in field, that Salix viminalis can remove Cd from agricultural soils and thereby reduce Cd accumulation in grains of wheat subsequently grown in a Salix-treated field. Four years of Salix cultivation reduce Cd concentration in the soil by up to 27% and in grains of the post-cultivated wheat by up to 33%. The higher the plant density of the Salix, the greater the Cd removal from the soil and the lower the Cd concentration in the grains of post-cultivated wheat, the Cd reduction remaining stable several years after Salix cultivation. The effect occurred in both sandy and clayey soil and in winter and spring bread wheat cultivars. Already one year of Salix cultivation significantly decrease Cd in post grown wheat grains. With this field experiment we have demonstrated that phytoextraction can reduce accumulation of a pollutant in post-cultivated wheat and that phytoextraction has no other observed effect on post-cultivated crops than reduced uptake of the removed pollutant.

  • 16.
    Greger, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Landberg, Tommy
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Rhizosphere interaction at Cd uptake by various wheat cultivars2007In: Scientific workshop on Phytotechnologies to promote sustainable land use and improve food safety, COST Action 859 workshop, Vilnius, June 2007, 2007Conference paper (Other (popular science, discussion, etc.))
  • 17.
    Greger, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Landberg, Tommy
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Role of rhizosphere mechanisms in Cd uptake by various wheat cultivars2008In: Plant and Soil, Vol. 312, p. 195-205Article in journal (Refereed)
  • 18.
    Greger, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Neuschütz, Clara
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Landberg, Tommy
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Göthberg, Agneta
    Department of Applied Environmental Science (ITM).
    Nyquist, Johanna
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Dabrowska, Beata
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Phytoremediation and metal uptake in food plants2007In: ECO-TECH 2007, 2007, p. 513-522Conference paper (Other academic)
    Abstract [en]

    This paper reviews some of our resent findings on metal uptake in phytotechnology and food plants. The Cd concentration in wheat grains can be decreased by pytoextraction by Salix prior to wheat cultivation. Water spinach commonly grown in nutrient rich waste water are able to form methyl-Hg in new leaves, but high nutrient level in cultivation medium decreases the metal concentration in the plant. Wetland plants grown on mine tailings are able to decrease the formation of acid mine drainage from the tailings. Submerged plants can increase the retention of metals in wetlands treating metal polluted water, but the efficiency depends on the quality of the inlet water. Plants can be used to prevent leakage of metals and nutrients from dry covers containing sewage sludge on mine tailing impoundments. If the sealing layer below the cover layer consists of fly ash root penetration can be prevented while if it contains a mixture of sewage sludge and fly ash roots will grow into the sealing layer. Macro algae as fertilizers in agriculture increase the biomass production but also transfer Cd to the crop. Therefore, algae should be used in production of non food crops, however, not suitable for hemp cultivation.

  • 19.
    Greger, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Wang, Yaodong
    Stockholm University, Faculty of Science, Department of Botany.
    Neuschütz, Clara
    Absence of Hg transpiration by shoot after Hg uptake by roots of six terrestrial plant species2005In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 134, no 2, p. 201-208Article in journal (Refereed)
    Abstract [en]

    In this paper we investigated if, and to what extent, six different plant species accumulate, translocate and emit mercury (Hg) into the air. The Hg uptake by roots, distribution of Hg to the shoot and release of Hg via shoots of garden pea, spring wheat, sugar beet, oil-seed rape, white clover and willow were investigated in a transpiration chamber. The airborne Hg was trapped in a Hopcalite trap or a gold trap. Traps and plant materials were analysed for content of Hg by CVAAS. The results show that all plant species were able to take up Hg to a large extent from a nutrient solution containing 200 μg L−1 Hg. However, the Hg translocation to the shoot was low (0.17–2.5%) and the Hg that reached the leaves was trapped and no release of the absorbed Hg to the air was detected.

    Mercury translocation to shoots was low.

  • 20.
    Homma, T
    et al.
    Japan.
    Mizuta, Y
    Japan.
    Jige, M
    Japan.
    Yokota, K
    Japan.
    Nagafuchi, O
    Japan.
    Matsuo, K
    Japan.
    Greger, M
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Luxova, Miroslav
    Academie of Science, Bratislava.
    Lux, Alexander
    Comenius University, Bratislava.
    Effects of cadmium treatment on tea plants.2008In: Abstract. Japanese Sociey for Root Research.: Root Research 17 (2)., 2008Conference paper (Other academic)
  • 21.
    Javed, M. Tariq
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Lindberg, Sylvia
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Cadmium uptake in Elodea canadensis leaves and its interference with extra- and intra-cellular pH2014In: Plant Biology, ISSN 1435-8603, E-ISSN 1438-8677, Vol. 16, no 3, p. 615-621Article in journal (Refereed)
    Abstract [en]

    This study investigated cadmium (Cd) uptake in Elodea canadensis shoots under different photosynthetic conditions, and its effects on internal (cytosolic) and external pH. The plants were grown under photosynthetic (light) or non-photosynthetic (dark or in the presence of a photosynthetic inhibitor) conditions in the presence or absence of CdCl2 (0.5 mu m) in a medium with a starting pH of 5.0. The pH-sensitive dye BCECF-AM was used to monitor cytosolic pH changes in the leaves. Cadmium uptake in protoplasts and leaves was detected with a Cd-specific fluorescent dye, Leadmium Green AM, and with atomic absorption spectrophotometry. During cultivation for 3days without Cd, shoots of E.canadensis increased the pH of the surrounding water, irrespective of the photosynthetic conditions. This medium alkalisation was higher in the presence of CdCl2. Moreover, the presence of Cd also increased the cation exchange capacity of the shoots. The total Cd uptake by E.canadensis shoots was independent of photosynthetic conditions. Protoplasts from plants exposed to 0.5 mu m CdCl2 for 3days did not exhibit significant change in cytosolic [Cd2+] or pH. However, exposure to CdCl2 for 7days resulted in increased cytosolic [Cd2+] as well as pH. The results suggest that E.canadensis subjected to a low CdCl2 concentration initially sequesters Cd into the apoplasm, but under prolonged exposure, Cd is transported into the cytosol and subsequently alters cytosolic pH. In contrast, addition of 10-50 mu m CdCl2 directly to protoplasts resulted in immediate uptake of Cd into the cytosol.

  • 22.
    Javed, M. Tariq
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Lindberg, Sylvia
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Cellular proton dynamics in Elodea canadensis leaves induced by cadmium2014In: Plant physiology and biochemistry (Paris), ISSN 0981-9428, E-ISSN 1873-2690, Vol. 77, p. 15-22Article in journal (Refereed)
    Abstract [en]

    Our earlier investigations showed that Elodea canadensis shoots, grown in the presence of cadmium (Cd), caused basification of the surrounding medium. The present study was aimed to examine the proton dynamics of the apoplastic, cytosolic and vacuolar regions of E. canadensis leaves upon Cd exposure and to establish possible linkage between cellular pH changes and the medium basification. The changes in cytosolic calcium [Ca2+](cyt) was also investigated as the [Ca2+](cyt) and [pH](cyt) homeostasis are closely linked. The cellular H+ and Ca2+ concentrations were monitored by fluorescence microscopy and ion-specific fluorescent dyes. Cadmium concentration of leaf-cell walls was measured after plant cultivation at different fixed levels of starting pH. The protoplasts from E. canadensis leaves were isolated by use of a newly developed enzymatic method. Upon Cd addition, both cytosolic and vacuolar pH of leaf protoplasts increased with a concomitant rise in the cytosolic Ca2+ concentration. Time course studies revealed that changes in [Ca2+](cyt) and [PH](cyt) followed similar dynamics. Cadmium (0.5 mu M) exposure decreased the apoplastic pH by 0.85 units. The maximum cell wall bound Cd-contents were obtained in plants grown at low starting pH. It is concluded that Cd treatment causes apoplastic acidosis in E. canadensis leaves associated with enhanced Cd binding to the cell walls and, consequently, reduced Cd influx into the cytosol.

  • 23.
    Javed, M. Tariq
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Stoltz, Eva
    Lindberg, Sylvia
    Stockholm University, Faculty of Science, Department of Botany.
    Greger, Maria
    Changes in pH and organic acids in mucilage of Eriophorum angustifolium roots after exposure to elevated concentrations of toxic elements2012In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 20, no 3, p. 1876-1880Article in journal (Refereed)
    Abstract [en]

    The presence of Eriophorum angustifolium in mine tailings of pyrite maintains a neutral pH, despite weathering, thus lowering the release of toxic elements into acid mine drainage water. We investigated if the presence of slightly elevated levels of free toxic elements triggers the plant rhizosphere to change the pH towards neutral by increasing organic acid content. Plants were treated with a combination of As, Pb, Cu, Cd and Zn at different concentrations in nutrient medium and in soil in a rhizobox-like system for 48-120 hrs. The pH and organic acids were detected in the mucilage dissolved from root surface, reflecting the rhizosphere solution. Also the pH of root-cell apoplasm was investigated. Both apoplasmic and mucilage pH increased and the concentrations of organic acids enhanced in the mucilage with slightly elevated levels of toxic elements. When organic acid concentration was high, also the pH was high. Thus, efflux of organic acids from the roots of E. angustifolium may induce rhizosphere basification.

  • 24.
    Javed, Muhammad Tariq
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Cadmium triggers Elodea canadensis to change the surrounding water pH and thereby Cd uptake2011In: International journal of phytoremediation, ISSN 1522-6514, E-ISSN 1549-7879, Vol. 13, no 1, p. 95-106Article in journal (Refereed)
    Abstract [en]

    This study was aimed to investigate the influence of Elodea canadensis shoots on surrounding water pH in the presence of cadmium and the effect of plant-induced pH on cadmium uptake. The pH change in the surrounding nutrient solution and Cd uptake by Elodea shoots were investigated after cultivation of various plant densities (1, 3, 6 plants per 500 ml) in hydroponics at a starting pH of 4.0 and in the presence of different concentrations of cadmium (0, 0.1, 0.5 µM). Cadmium uptake was also investigated at different constant pH (4.0, 4.5, 5.5 and 6.5). To investigate if the pH change arose from photosynthetic activities, plants were grown under light, darkness or in the presence of a photosynthetic inhibitor, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), and 0.5 µM cadmium in the solution. Elodea had an ability to increase the surrounding water pH, when the initial pH was low, which resulted in increased accumulation of Cd. The higher the plant density, the more pronounced was the pH change. The pH increase was not due to the photosynthetic activity since the pH rise was more pronounced under darkness and in the presence of DCMU. The pH increase by Elodea was triggered by cadmium.

  • 25.
    Javed, Muhammad Tariq
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Lindberg, Sylvia
    Stockholm University, Faculty of Science, Department of Botany.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Cytosolic uptake of cadmium causes an extra- and intra-cellular basification in Elodea canadensisManuscript (preprint) (Other academic)
    Abstract [en]

    The current study was aimed to investigate the pH changes by Elodea canadensis shoots under different photosynthetic conditions in the presence and absence of cadmium (Cd) and its influence on Cd uptake. Plants were grown under light, dark and in the presence of the photosynthetic inhibitor (3-(3,4-dichlorophenyl)-1,1-dimethylurea) with and without 0.5 µM Cd in the solution at a starting pH of 5.0. The Cd uptake into the cytosol of leaf protoplasts was investigated by using a Cd-specific fluorescent dye, LeadmiumTM Green AM. Cadmium and proton dynamics were monitored in leaf protoplasts after plant exposure to 0.5 µM CdCl2 for 3 and 7 d, respectively. The pH sensitive dye BCECF-AM was used to detect cytosolic pH changes. The shoots increased the surrounding water pH, which enhanced Cd uptake. Beside pH increase by photosynthetic activity, E. canadensis possessed additional mechanisms to raise the surrounding water pH in the presence of Cd. The cytosolic cadmium (Cd2+cyt) fluorescence of leaf protoplasts increased upon addition of CdCl2 to the external medium, reflecting (Cd2+cyt) uptake. Plant exposure to 0.5 µM CdCl2 for 3 d did not induce significant changes in (Cd2+cyt)and [pH]cyt. However, the (Cd2+cyt) and pHcyt were significantly increased after plant exposure to 0.5 µM CdCl2 for 7d. This suggests that E. canadensis initially sequester Cd in its apoplasmic region depending upon the presence of acidic polysaccharides in its cell wall and external medium basification. With time Cd translocates into the cytosol and subsequently causes its basification.

  • 26.
    Javed, Muhammad Tariq
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Lindberg, Sylvia
    Stockholm University, Faculty of Science, Department of Botany.
    Maria, Greger
    Stockholm University, Faculty of Science, Department of Botany.
    Cadmium induces cellular pH changes in Elodea canadensis and causes external basificationArticle in journal (Refereed)
    Abstract [en]

    Earlier investigations showed that Elodea canadensis causes a basification of the surrounding medium in the presence of cadmium. This study was aimed to investigate the mechanism by which Cd causes this plant to increase the surrounding water pH. Cd-induced pH changes in cytosol, vacuole and apoplastic regions of E. canadensis were monitored by fluorescence microscopy and pH-specific fluorescent dyes. Since cytosolic Ca2+ and pH homeostasis are closely linked, the cytosolic calcium [Ca2+]cytwas also investigated after Cd treatment. Cd binding to the cell walls of E. canadensis was investigated after cultivation of plants at different fixed pH. We developed a new enzymatic method for the isolation of protoplasts from E. canadensis leaves. Cd exposure resulted in a subsequent increase in both cytosolic and vacuolar pH of leaf protoplasts and concomitant rise in the [Ca2+]cyt. Changes in [Ca2+]cyt and [pH]cyt followed the same dynamics upon Cd addition, but the changes in [pH]cyt seemed to be prior to the [Ca2+]cyt changes. Cd treatment decreased the apoplastic pH by 0.85 units and Cd contents of cell walls were enhanced at low pH. In conclusion, Cd exposure decreased the apoplastic pH of E. canadensis and resulted in Cd binding to the cell walls which may prevent Cd influx to the cytosol. The results suggest that the Cd-induced apoplastic acidification can be one of the mechanisms to increase the surrounding medium pH by E. canadensis shoots.

  • 27.
    Javed, Muhammad Tariq
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Stoltz, Eva
    Lindberg, Sylvia
    Stockholm University, Faculty of Science, Department of Botany.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    pH changes and organic acids exudation by Eriophorum angustifolium roots exposed to elevated concentration of toxic elementsArticle in journal (Refereed)
    Abstract [en]

    This study was aimed to investigate the influence of Eriophorum angustifolium roots on surrounding water pH in the presence of heavy metals and As, and the possible mechanism behind. We monitored the pH in the surrounding nutrient solution by E. angustifolium roots at a starting pH 3.5 and in the presence of a combination of As, Pb, Cu, Cd and Zn at different concentrations. The metal and As contents in the plant shoots and roots were analyzed as well as organic acids in the root exudates. Fluorescence microscopy and a pH-specific fluorescent dye were used to investigate the influence of different elements on apoplastic pH of E. angustifolium roots. The results showed that the roots have the ability to increase the rhizosphere pH even in the presence of different free metal ions and As. The plant root metal and As contents were significantly higher as compared with shoots. Metal and As treatment at higher concentrations significantly caused the apoplastic pH to increase in this species. Of the acids analyzed, the exudation of the oxalic, formic and succinic acids was significantly enhanced after metal and As exposure, as compared with control, giving the maximum concentration of these acids after 25 µM As, Cu, Zn, Pb and 2.5 µM Cd treatment. The roots of E. angustifolium respond to toxic ions by releasing organic acids, which transiently induce rhizosphere basification.

  • 28.
    Landberg, Tommy
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Jensen, P.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Strategies of cadmium and zinc resistance in willow by regulation of net accumulation2011In: Biologia plantarum, ISSN 0006-3134, E-ISSN 1573-8264, Vol. 55, no 1, p. 133-140Article in journal (Refereed)
    Abstract [en]

    This work was performed to find out if metal resistant clones of Salix viminalis L. are capable to achieve high resistance to the metals by regulating their net accumulation. Salix clones with low or high resistance in combination with low or high accumulation capacity of either Zn or Cd were cultivated from cuttings in nutrient solution. The investigation included leakage and uptake experiments using (65)Zn or (109)Cd and analysis of root cation exchange capacity (CEC). Some plants were pre-treated with unlabeled 0.5 mu M Cd or 2.5 mu M Zn 24 h prior to the experiments to induce possible tolerance mechanisms. To find out if the regulation was a metabolic process, experiments were also performed with 2,4-dinitrophenol (DNP). Clones with high resistance and low Cd accumulation had higher efflux of Cd compared to the other clones, in both untreated and Cd pre-treated plants. This indicates a constitutive property to lower Cd accumulation by high Cd leakage. Pre-treatment with 0.5 mu M Cd diminished the Cd net uptake to a level near zero in all clones, likely to be due to decreased the Cd uptake. In contrast, resistant clones with high Cd accumulation had the highest root CEC, which may be used to bind up Cd in the free space. No clear regulation of Zn net uptake was found in Zn-resistant clones. Pre-treatment with Zn decreased the uptake of Zn into the free space in Zn-resistant clones. The resistant high-accumulating clones, however, showed the highest leakage of Zn in both untreated and pre-treated plants, a constitutive process not related to high accumulation. Neither the influx nor the efflux of Cd or Zn was affected by DNP indicating passive transport across the plasma membrane.

  • 29. Nazaralian, Sanam
    et al.
    Majd, Ahmad
    Irian, Saeed
    Najafi, Farzaneh
    Ghahremaninejad, Farrokh
    Landberg, Tommy
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Comparison of silicon nanoparticles and silicate treatments in fenugreek2017In: Plant physiology and biochemistry (Paris), ISSN 0981-9428, E-ISSN 1873-2690, Vol. 115, p. 25-33Article in journal (Refereed)
    Abstract [en]

    Silicon (Si) fertilization improves crop cultivation and is commonly added in the form of soluble silicates. However, most natural plant-available Si originates from plant formed amorphous SiO2 particles, phytoliths, similar to SiO2-nanoparticles (SiNP). In this work we, therefore, compared the effect by sodium silicate and that of SiNP on Si accumulation, activity of antioxidative stress enzymes catalase, peroxidase, superoxide dismutase, lignification of xylem cell walls and activity of phenylalanine ammonia-Iyase (PAL) as well as expression of genes for the putative silicon transporter (PST), defensive (Tfgd 1) and phosphoenolpyruvate carboxykinase (PEPCK) and protein in fenugreek (Trigonella foenum-graecum L) grown in hydroponics. The results showed that Si was taken up from both silicate and SiNP treatments and increasing sodium silicate addition increased the translocation of Si to the shoot, while this was not shown with increasing SiNP addition. The silicon transporter PST was upregulated at a greater level when sodium silicate was added compared with SiNP addition. There were no differences in effects between sodium silicate and SiNP treatments on the other parameters measured. Both treatments increased the uptake and accumulation of Si, xylem cell wall lignification, cell wall thickness, PAL activity and protein concentration in seedlings, while there was no effect on antioxidative enzyme activity. Tfgd 1 expression was strongly downregulated in leaves at Si addition. The similarity in effects by silicate and SiNP would be due to that SiNP releases silicate, which may be taken up, shown by a decrease in SiNP particle size with time in the medium.

  • 30.
    Neuschütz, Clara
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Boström, Dan
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Root growth into sealing layers of fly ash2010In: Journal of Plant Interactions, ISSN 1742-9145, Vol. 5, no 2, p. 75-85Article in journal (Refereed)
    Abstract [en]

    Fly ash can be used as sealing material on mine waste disposal sites. Our aim was to determine the penetration resistance necessary to prevent root penetration of ash sealing layers, and investigate whether plants can affect the layer strength. We analyzed the root penetration, pH, EC and penetration resistance of layers on which Phalaris arundinacea, Salix myrsinifolia, Epilobium angustifolium, and Pinus sylvestris had been growing for 4-8 months in a greenhouse. Fly ashes obtained from the incineration of biofuel or municipal solid waste were used. A penetration resistance of similar to 1.5 MPa generally prevented root penetration, but roots of P. arundinacea could grow into the surface of layers with similar to 5 MPa penetration resistance. We examined the loosening ability of agents found in root exudates and the mineralogy of rhizosphere ash. The roots increased the weathering of the ash, including dissolution of secondary calcium minerals, possibly related to saccharide exudation.

  • 31.
    Neuschütz, Clara
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Stabilization of mine tailings using fly ash and sewage sludge planted with Phalaris arundinacea L2010In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 207, no 1-4, p. 357-367Article in journal (Refereed)
    Abstract [en]

    The impact of plants (Phalaris arundinacea L.) on the leakage of ammonium, cadmium, copper, nitrate, phosphate, and zinc from sulfidic mine tailings covered with wood fly ash and sewage sludge was investigated. Either ash or sludge was placed in contact with the tailings, and ash layers of either low or high compactness were used. It was revealed that an ash/sludge cover effectively decreased the metal leaching from the tailings regardless of the order in which the materials were applied. Plants decreased the amount of leachate and the concentrations of ammonium and phosphate. The presence of ash below the sludge decreased the plant uptake of copper and zinc and nitrate leakage. However, when the ash was added as a thin (1.5 cm) porous layer, roots and air reached the tailings and caused high metal leakage. The results support the use of a vegetated ash/sludge cover in the treatment of mine tailings, provided that the sealing layer is firm enough to prevent root penetration.

  • 32. Nyquist, Johanna
    et al.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    A field study of constructed wetlands for preventing and treating acid mine drainage2009In: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, Vol. 35, no 5, p. 630-642Article in journal (Refereed)
    Abstract [en]

    The formation of acid mine drainage (AMD) from mine tailings is a severe environmental problem associated with tailings impoundments. The study evaluated the ability of wetlands built on tailings impoundments to prevent AMD formation and to treat already formed AMD, with special emphasis on the role of wetland plants in the remediation process. Four small-scale surface-flow wetlands of different designs, containing either mine tailings or sand, an inflow of AMD or unpolluted water, and with or without emergent plants (Phragmites australis, Carex rostrata, and Eriophorum angustifolium), were constructed at the Kristineberg mine tailings impoundment in northern Sweden in 2004. Water samples were collected every month in 2006 at inflow and outflow in order to analyse metals, sulphate, pH, and redox potential. At the end of 2006, plant and sediment samples were collected to enable the analysis of metal concentrations. The concentrations of Fe, Zn, Cd, and sulphate and pH did not change after passage through the wetlands treating AMD. However, the Cu concentration decreased by 36-57%, with the decrease higher in the presence than in the absence of plants. The study of AMD prevention indicated that metal concentrations in impoundment water tend to decrease as the water passes through the wetland. However, sulphate concentrations increase and the pH decreases in the water, suggesting sulphide oxidation of the mine tailings. On the other hand, wetland plants increased the pH, decreased the redox potential, and increased the metal concentrations in the substrate, despite the fact that metal uptake in the studied wetland plants accounted for only 0.002-2.9% of the annual metal loading into the wetlands, suggesting that plants promote metal sedimentation and adsorption. Emergent plants and the wetlands constructed in this study were thus inadequate to treat the very harsh AMD at the Kristineberg mine site.

  • 33.
    Nyquist, Johanna
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Response of two wetland plant species to Cd exposure at low and neutral pH2009In: Environmental and Experimental Botany, ISSN 0098-8472, E-ISSN 1873-7307, Vol. 65, no 2-3, p. 417-424Article in journal (Refereed)
    Abstract [en]

    Emerged and submerged plants are used in treating various metal-containing wastewaters, such as stormwater (neutral pH) and acid mine drainage (low pH). The aim was to investigate the appearance of a set of possible mechanisms to detoxify Cd in plants and whether their appearance differ due to the surrounding pH and/or plant type. One emergent (Carex rostrata) and one submerged (Elodea canadensis) macrophyte were exposed to 0, 0.05, and 0.5 μM Cd for 3 d in hydroponic solutions at pH 3.5 and 6.9. We analysed cadmium accumulation, thiol-rich peptide concentrations and cell wall-bound Cd in plants, organic acid content and pH change in surrounding water cation exchange capacity (CEC) of plant tissue. Both plant species accumulated Cd in their tissues, and thus did not exclude it and C. rostrata decreased the relative Cd distribution to its shoots with increasing Cd addition. In both species, Cd was immobilized through cell wall binding, and thiol-rich peptides synthesized in the presence of Cd that may participate in Cd binding. In addition, E. canadensis increased its CEC by synthesizing new metal-binding sites in the cell walls. Organic acid composition in surrounding water did not change with Cd addition and had no effect on Cd detoxification. However, E. canadensis increased the surrounding pH from pH 3.5 in the presence of Cd; the surrounding pH did not, however, influence the detoxification mechanisms.

  • 34.
    Nyquist, Johanna
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Uptake of Zn, Cu, and Cd in metal loaded Elodea canadensis2007In: Environmental and Experimental Botany, ISSN 0098-8472, E-ISSN 1873-7307, Vol. 60, no 2, p. 219-226Article in journal (Refereed)
    Abstract [en]

    Since uptake of metals in submerged plants can have a positive effect on the total remediation efficiency in a wetland it is important to investigate factors that possibly can have an effect on uptake of metals. In this short term study we investigated whether the tissue concentration of Zn, Cu and Cd influenced further uptake by metals in Elodea canadensis. Stress effects in response to metal exposure were also investigated. Plants were first loaded with metals for 48 h followed by a metal exposure period of 72 h. Metals in plant tissue and stress effects on plants were analysed both prior to, and after exposure. The results showed that tissue concentration of Zn and Cu did not have effect on further uptake, however for Cd it did have an effect. During Cd exposure accumulated Cd started to leak out of the plants where a decreased leakage could be seen with increased exposure concentration of Cd. The degree of metals binding to the cell wall could explain the influence of tissue concentration on uptake. These results are relevant to the phytoremediation technology area, where it is of great importance to achieve knowledge of commonly used plant species in treatment wetlands to optimise treatment of polluted areas.

  • 35.
    Ohlsson, Anna
    et al.
    KTH.
    Landberg, Tommy
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Berglund, Torkel
    KTH.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Increased metal tolerance in Salix by nicotinamide and nicotinic acid.2008In: Plant physiology and Biochemistry, Vol. 46, p. 655-664Article in journal (Refereed)
  • 36.
    Sandhi, Arifin
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. KTH Royal Institute of Technology, Sweden.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Landberg, Tommy
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Jacks, Gunnar
    Bhattacharya, Prosun
    Arsenic concentrations in local aromatic and high-yielding hybrid rice cultivars and the potential health risk: a study in an arsenic hotspot2017In: Environmental Monitoring & Assessment, ISSN 0167-6369, E-ISSN 1573-2959, Vol. 189, no 4, article id 184Article in journal (Refereed)
    Abstract [en]

    The presence of high levels of arsenic (As) in rice fields has negative effects on the health of those consuming rice as their subsistence food. This study determined the variation in total As concentration in local aromatic rice (LAR) (kalijira) and two high-yielding varieties (HYVs) (BRRI dhan 32 and BRRI dhan 28) grown in paddy fields in Matlab, Bangladesh, an As hotspot with elevated As levels in groundwater. Mature rice grain samples and soil samples were collected from different paddy fields, and the As concentrations in both the de-husked grains and the husks of the three rice cultivars were analysed to identify the safest of the three cultivars for human consumption. The results showed that the total As concentration was higher (0.09-0.21 mg As kg(-1)) in the de-husked grains of LAR than in the husks, while the opposite was found for the HYVrice. Moreover, the As concentration in soil samples was 2 to 5-fold higher for the LAR than for the HYVs, but the As accumulation factor (AF) was lower in the LAR (0.2-0.4%) than in the HYVs (0.9-1%). Thus, LAR can be considered the safest of the three cultivars for human consumption owing to its low AF value. Furthermore, due to the low AF, growing LAR instead of HYVs in soils with slightly elevated As levels could help improve the food safety level in the food chain.

  • 37.
    Sandhi, Arifin
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. KTH Royal Institute of Technology, Sweden.
    Landberg, Tommy
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Phytofiltration of arsenic by aquatic moss (Warnstorfia fluitans)2018In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 237, p. 1098-1105Article in journal (Refereed)
    Abstract [en]

    This work investigates whether aquatic moss (Warnstorfia fluitans) originating from an arsenic (As) contaminated wetland close to a mine tailings impoundment may be used for phytofiltration of As. The aim was to elucidate the capacity of W. fluitans to remove As from arsenite and arsenate contaminated water, how nutrients affect the As uptake and the proportion of As adsorption and absorption by the moss plant, which consists of dead and living parts. Arsenic removal from 0, 1, or 10% Hoagland nutrient solution containing 0-100 mu M arsenate was followed over 192 h, and the total As in aquatic moss after treatment was analysed. The uptake and speciation of As in moss cultivated in water containing 10 mu M arsenate or arsenite were examined as As uptake in living (absorption + adsorption) and dead (adsorption) plant parts. Results indicated that W. fluitans removed up to 82% of As from the water within one hour when 1 mu M arsenate was added in the absence of nutrients. The removal time increased with greater nutrient and As concentrations. Up to 100 mu M As had no toxic effect on the plant biomass. Both arsenite and arsenate were removed from the solution to similar extents and, independent of the As species added, more arsenate than arsenite was found in the plant. Of the As taken up, over 90% was firmly bound to the tissue, a possible mechanism for resisting high As concentrations. Arsenic was both absorbed and adsorbed by the moss, and twice as much As was found in living parts as in dead moss tissue. This study revealed that W fluitans has potential to serve as a phytofilter for removing As from As-contaminated water without displaying any toxic effects of the metalloid.

  • 38.
    Stoltz, Eva
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Effects of Different Wetland Plant Species on Fresh Unweathered Sulphidic Mine Tailings2005In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 276, no 1-2, p. 251-261Article in journal (Refereed)
    Abstract [en]

     

     

     

     

     

     

     

     

     

    Vegetation cover with two

    Eriophorum species on old unweathered sulphidic mine tailings has earlier been found to reduce the element levels and to prevent production of acidity in drainage water. The present study aims to find out if Carex rostrata Stokes, Eriophorum angustifolium Honck. and Phragmites australis (Cav.) Steud. had other effects on metal and As release in fresh unweathered sulphidic mine tailings, if the species showed different effects and if this depended on plant mechanisms such as O2, carbonate or organic acid release. Plants were grown in pots with fresh sulphidic mine tailings for 13 months. Arsenic, Cd, Cu, Fe, Pb,Zn, pH, SO42), alkalinity and organic acids in the drainage water as well as metals and As in roots and shoot and O2 and redox potential in pore water were analysed. The tailings weathered slowly due to high buffering capacity thus no pH decrease was found and therefore similar buffering effects by plants as shown in the previous investigation could not be found. The plants increased the total release of metals and As from the tailings. The release did not depend on carbonate or organic acid release from plants. However,the Fe and As release was due to changed redox potential, caused by O2 release, and high concentration of Fe and As was found in plant roots. Phragmites australis released more As and Fe but less Cd than E. angustifolium and C. rostrata which make P. australis not suitable for plant establishment on sulphidic mine tailings containing high levels of As. Plants did take up the elements and the lowest translocation of elements to the shoot was found in P. australis while the highest in E. angustifolium

    .

  • 39.
    Stoltz, Eva
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Influences of wetland plants on weathered acidic mine tailings2006In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 144, no 2, p. 689-694Article in journal (Refereed)
    Abstract [en]

    Establishment of Carex rostrata, Eriophorum angustifolium and Phragmites australis on weathered, acidic mine tailings (pH 3) and their effect on pH in tailings were investigated in a field experiment. The amendments, sewage sludge and an ashes–sewage sludge mixture, were used as plant nutrition and their influence on the metal and As concentrations of plant shoots was analysed. An additional experiment was performed in greenhouse with E. angustifolium and sewage sludge as amendments in both weathered and unweathered tailings. After one year, plants grew better in amendments containing ashes in the field, also in those plants the metal and As shoot concentrations were generally lower than in other treatments. After two years, the only surviving plants were found in sewage sludge mixed with ashes. No effect on pH by plants was found in weathered acidic mine tailings in either field- or greenhouse experiment. Wetland plant establishment on acidic mine tailings may contribute to a reduced metal release and a stabilisation of pH.

  • 40.
    Stoltz, Eva
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Release of metal and arsenik from various mine tailings by Eriophorum angustifolium2006In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 289, no 1-2, p. 199-210Article in journal (Refereed)
    Abstract [en]

     

     

     

     

     

     

    Previous investigations have found that plants grown on sulphide-rich mine tailings have phytostabilising effects on acid mine drainage (AMD) by decreasing the pH and preventing the release of metals. The possibility of similar effects on tailings containing other minerals was investigated here. The aim was to examine the effects of Eriophorum angustifolium on four  water-covered mine tailings with different mineralogy – i.e. the plants’ effect on the release of elements from the tailings and the uptake of elements – to reveal if E. angustifolium  is suitable for phytostabilisation in various tailings. Seeds of E. angustifolium were sown in different tailings amended with sewage sludge. Arsenic, Cd, Cu, Fe, Pb and Zn levels in the drainage water and in plant tissues were examined. pH, alkalinity, SO2 4 and organic acid concentrations were measured in drainage water, and redox potential and O2 levels in the pore water. The effect of E. angustifolium on the release of metals from the tailings varied with the composition of the tailings. In tailings with a low buffering capacity and low element and sulphide levels, compared with the other tailings, E. angustifolium increased the release of metals, which was shown by the concentrations of elements and low pH in the drainage water and high concentrations of elements in theshoots, thereby generating a bio-concentration factor (BCF) >1. In tailings with a high concentration of elements, the plants had little effect on the levels of the elements in the drainage water, likely due to the presence of buffering agents in the tailings (added prior to the experiment). In this case, the pH did not decrease in the presence of plants and the shoot BCF was <1.

     

  • 41.
    Wang, Yaodong
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Use of iodide to enhance the phytoextraction of mercury-contaminated Soil2006In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 368, no 1, p. 30-39Article in journal (Refereed)
    Abstract [en]

    Low bioavailability of mercury (Hg) in soil is a restricting factor in phytoextraction of Hg-contaminated soil. Iodide is known to mobilize Hg in soil and, therefore, the aim of this study was to investigate the possibility to use iodide to increase phytoextraction of Hg. The sensitivity of willow to iodide was investigated in both hydroponics with 0–10 mM KI and in soil with 0.2 and 1 mM KI addition. The capacity to accumulate HgI2 was compared with that of Hg(NO3)2 in hydroponics. Soil extractions with 0–2 mM KI were used to study mobilization of Hg in aged Hg-spiked soil. Additions of KI (0.2–1 mM) were used in pot tests with aged Hg-spiked soil as well as in field trials in an industrial Hg-contaminated soil to study whether iodide addition increased the accumulation of Hg from contaminated soil and the translocation of Hg to the shoots. The total Hg contents in plants, soils and extracts were analyzed by CVAAS. The results showed that too high KI concentration was toxic to plants. Moreover, KI was toxic to plants at lower concentrations in hydroponics than in soil additions. KI (85 μM) in hydroponics gave 50% growth decrease in terms of dry weight of shoot biomass, whereas 0.2 mM KI in soil addition could be tolerated by the plant without growth disturbance. Willow accumulated Hg from HgI2 solution slower than that from Hg(NO3)2 solution. KI mobilized Hg in contaminated soil and thereby increased the bioavailability of Hg in soil. Up to 1 mM KI addition increased the Hg concentrations to about 5, 3 and 8 times, respectively, in the leaves, branches and roots. However, the Hg translocation to the shoots did not show an increase with KI addition. Only less than 1% of the total Hg accumulated in the plant was distributed in the shoots. We may conclude that iodide addition enhances the phytoextraction of Hg, however, the translocation of Hg to the shoots is still too low and therefore it will not be realistic to use this method for phytoextraction of Hg-contaminated soil in practice.

  • 42.
    Wang, Yaodong
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Stauffer, Clotide
    Keller, Catherine
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Changes in Hg fractionation in soil induced by willow2005In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 275, no 1-2, p. 67-75Article in journal (Refereed)
    Abstract [en]

    This study investigated the effect of willow (Salix viminalis ×  S. schwerinii) on soil characteristics, including changes in Hg fractionation in the soil solid phase, and Hg accumulation and distribution in pot-grown plants cultivated for 32 and 76 days in aged Hg-contaminated soil (30 mg Hg kg−1DW). Changes in soil pH and organic carbon content as well as in Hg fractionation were monitored in both rhizospheric soil and in soil without plants. Mercury fractionation was performed by a 5-step sequential soil extraction procedure. Organic carbon content increased while pH decreased in the rhizospheric soil. Both chemically defined exchangeable Hg (0.1) and Hg bound to humic and fulvic acids (1.1) decreased in the rhizospheric soil, whereas plant accumulation of Hg increased with cultivation time. The sum of the decrease of these two soil Hg fractions after 76 days of cultivation was approximately equal to the amount of Hg accumulated in plants. Furthermore, the major Hg fractions (Hg bound to residual organic matter (53), sulphides (43), and the residual fraction (2.5)) remained stable. Neither whole plant accumulation of Hg from the soil, approximately 0.2 of total Hg in soil after 76 days cultivation, nor the fraction of total plant Hg in the shoots, which accounted for about 3 of the total plant Hg pool regardless of the cultivation time, were high. The overall results suggest that plants might be suitable for phytostabilization of aged Hg-contaminated soil, where root systems trap bioavailable Hg and help to control both leaching of Hg and re-entrainment of Hg-containing particulates from a contaminated site.

  • 43.
    Österås, Ann Helén
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Interactions between Ca and Cu or Cd in Norway spruce2006In: Biologia plantarum, ISSN 0006-3134, E-ISSN 1573-8264, Vol. 50, no 4, p. 647-652Article in journal (Refereed)
    Abstract [en]

    The accumulation of calcium (Ca), copper (Cu) and cadmium (Cd) in roots and stem of Norway spruce (

    Picea abies

    [L.]

    Karst) was examined. Two-year-old Norway spruce seedlings were treated with elevated concentrations of Ca, Cd or Cu, or as combinations of Ca with Cu or Cd in nutrient solutions for three months. The stem was divided into bark, wood formed during the treatment period (new wood), and wood formed before the treatment period (old wood). The accumulation of the metals in stem and roots increased with addition of the respective metal into nutrient solution.

    Addition of Cu decreased the accumulation of Ca in roots and wood, and Ca addition decreased the accumulation of Cu in the new wood. By adding Ca in combination with Cu the accumulation of Cu in the stem was decreased even more by Ca and the negative effect of Cu on the Ca content in the stem was diminished. Addition of Cd decreased the accumulation of Ca in wood, especially the old wood, and Ca addition decreased the accumulation of Cd in roots, bark and new wood. By adding Ca in combination with Cd the Ca content was reduced in the bark, instead of in the old wood.

1 - 43 of 43
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