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Sample records for hyperaccumulator thlaspi caerulescens1w

  1. Increased glutathione biosynthesis plays a role in nickel tolerance in thlaspi nickel hyperaccumulators.

    PubMed

    Freeman, John L; Persans, Michael W; Nieman, Ken; Albrecht, Carrie; Peer, Wendy; Pickering, Ingrid J; Salt, David E

    2004-08-01

    Worldwide more than 400 plant species are now known that hyperaccumulate various trace metals (Cd, Co, Cu, Mn, Ni, and Zn), metalloids (As) and nonmetals (Se) in their shoots. Of these, almost one-quarter are Brassicaceae family members, including numerous Thlaspi species that hyperaccumulate Ni up to 3% of there shoot dry weight. We observed that concentrations of glutathione, Cys, and O-acetyl-l-serine (OAS), in shoot tissue, are strongly correlated with the ability to hyperaccumulate Ni in various Thlaspi hyperaccumulators collected from serpentine soils, including Thlaspi goesingense, T. oxyceras, and T. rosulare, and nonaccumulator relatives, including T. perfoliatum, T. arvense, and Arabidopsis thaliana. Further analysis of the Austrian Ni hyperaccumulator T. goesingense revealed that the high concentrations of OAS, Cys, and GSH observed in this hyperaccumulator coincide with constitutively high activity of both serine acetyltransferase (SAT) and glutathione reductase. SAT catalyzes the acetylation of l-Ser to produce OAS, which acts as both a key positive regulator of sulfur assimilation and forms the carbon skeleton for Cys biosynthesis. These changes in Cys and GSH metabolism also coincide with the ability of T. goesingense to both hyperaccumulate Ni and resist its damaging oxidative effects. Overproduction of T. goesingense SAT in the nonaccumulator Brassicaceae family member Arabidopsis was found to cause accumulation of OAS, Cys, and glutathione, mimicking the biochemical changes observed in the Ni hyperaccumulators. In these transgenic Arabidopsis, glutathione concentrations strongly correlate with increased resistance to both the growth inhibitory and oxidative stress induced effects of Ni. Taken together, such evidence supports our conclusion that elevated GSH concentrations, driven by constitutively elevated SAT activity, are involved in conferring tolerance to Ni-induced oxidative stress in Thlaspi Ni hyperaccumulators. PMID:15269333

  2. Investigating Heavy-metal Hyperaccumulation using Thlaspi caerulescens as a Model System

    PubMed Central

    Milner, Matthew J.; Kochian, Leon V.

    2008-01-01

    Background Metal-hyperaccumulating plant species are plants that are endemic to metalliferous soils and are able to tolerate and accumulate metals in their above-ground tissues to very high concentrations. One such hyperaccumulator, Thlaspi caerulescens, has been widely studied for its remarkable properties to tolerate toxic levels of zinc (Zn), cadmium (Cd) and sometimes nickel (Ni) in the soil, and accumulate these metals to very high levels in the shoot. The increased awareness regarding metal-hyperaccumulating plants by the plant biology community has helped spur interest in the possible use of plants to remove heavy metals from contaminated soils, a process known as phytoremediation. Hence, there has been a focus on understanding the mechanisms that metal-hyperaccumulator plant species such as Thlaspi caerulescens employ to absorb, detoxify and store metals in order to use this information to develop plants better suited for the phytoremediation of metal-contaminated soils. Scope In this review, an overview of the findings from recent research aimed at better understanding the physiological mechanisms of Thlaspi caerulescens heavy-metal hyperaccumulation as well as the underlying molecular and genetic determinants for this trait will be discussed. Progress has been made in understanding some of the fundamental Zn and Cd transport physiology in T. caerulescens. Furthermore, some interesting metal-related genes have been identified and characterized in this plant species, and regulation of the expression of some of these genes may be important for hyperaccumulation. Conclusions Thlaspi caerulescens is a fascinating and useful model system not only for studying metal hyperaccumulation, but also for better understanding micronutrient homeostasis and nutrition. Considerable future research is still needed to elucidate the molecular, genetic and physiological bases for the extreme metal tolerance and hyperaccumulation exhibited by plant species such as T. caerulescens. PMID:18440996

  3. MOLECULAR AND PHYSIOLOGICAL INVESTIGATIONS OF THLASPI CAERULESCENS, A ZN/CD HYPERACCUMULATOR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Certain plant species have evolved specialized mechanisms that allow them to grow and thrive on metalliferous soils and accumulate high levels of heavy metals in the shoots that are toxic to normal plants. One such plant species is Thlaspi caerulescens, a Zn and Cd hyperaccumulator, and its metal h...

  4. CHARACTERIZATION OF ZINC TOLERANCE GENES IN THE ZINC/CADMIUM HYPERACCUMULATOR, THLASPI CAERULESCENS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thlaspi caerulescens, a heavy metal hyperaccumulating plant species, accumulates up to 30,000 ppm zinc in the above ground biomass without exhibiting toxicity symptoms. Previous work in our lab has shown that altered regulation of micronutrient uptake, transport and sequestration in this species pla...

  5. Hyperaccumulation of cadmium by hairy roots of Thlaspi caerulescens

    SciTech Connect

    Nedelkoska, T.V.; Doran, P.M.

    2000-03-05

    Hairy roots were used to investigate cadmium uptake by Thlaspi caerulescens, a metal hyperaccumulator plant with potential applications in phytoremediation and phytomining. Experiments were carried out in nutrient media under conditions supporting root growth. Accumulation of Cd in short-term (9-h) experiments varied with initial medium pH and increased after treating the roots with H{sup +}-ATPase inhibitor. The highest equilibrium Cd content measured in T. caerulescens roots was 62,800 {micro}g g{sup {minus}1} dry weight, or 6.3% dry weight, at a liquid Cd concentration of 3,710 ppm. Cd levels in live T. caerulescens roots were 1.5- to 1.7-fold those in hairy roots of nonhyperaccumulator species exposed to the same Cd concentration, but similar to the Cd content of auto-claved T. caerulescens roots. The ability to grow at Cd concentrations of up to 100 ppm clearly distinguished T. caerulescens hairy roots from the nonhyperaccumulators. The specific growth rate of T. caerulescens roots was essentially unaffected by 20 to 50 ppm Cd in the culture medium; in contrast, N. tabacum roots turned dark brown at 20 ppm and growth was negligible. Up to 10,600 {micro}g g{sup {minus}1} dry weight Cd was accumulated by growing T. caerulescens hairy roots. Measurement of Cd levels in while roots and in the cell wall fraction revealed significant differences in the responses of T. caerulescens and N. tabacum roots to 20 ppm Cd. Most metal was transported directly into the symplasm of N. tabacum roots within 3 days of exposure; in contrast, T. caerulescens roots stored virtually all of their Cd in the wall fraction for the first 7 to 10 days. This delay in transmembrane uptake may represent an important defensive strategy against Cd poisoning in T. caerulescens, allowing time for activation of intracellular mechanisms for heavy metal detoxification.

  6. ECOTYPIC VARIATION IN THE TRANSPORT, COMPARTMENTATION, AND COORDINATION OF CD BETWEEN POPULATIONS OF THE METAL HYPERACCUMULATOR, THLASPI CAERULESCENS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The hyperaccumulator Thlaspi caerulescens is known for its ability to hyperaccumulate and tolerate cadmium and zinc. This species is found in isolated, often small, populations across Great Britain, France, Belgium, and other European countries. While T. caerulescens populations from these different...

  7. The molecular physiology of heavy metal transport in the Zn/Cd hyperaccumulator Thlaspi caerulescens

    PubMed Central

    Pence, Nicole S.; Larsen, Paul B.; Ebbs, Stephen D.; Letham, Deborah L. D.; Lasat, Mitch M.; Garvin, David F.; Eide, David; Kochian, Leon V.

    2000-01-01

    An integrated molecular and physiological investigation of the fundamental mechanisms of heavy metal accumulation was conducted in Thlaspi caerulescens, a Zn/Cd-hyperaccumulating plant species. A heavy metal transporter cDNA, ZNT1, was cloned from T. caerulescens through functional complementation in yeast and was shown to mediate high-affinity Zn2+ uptake as well as low-affinity Cd2+ uptake. It was found that this transporter is expressed at very high levels in roots and shoots of the hyperaccumulator. A study of ZNT1 expression and high-affinity Zn2+ uptake in roots of T. caerulescens and in a related nonaccumulator, Thlaspi arvense, showed that alteration in the regulation of ZNT1 gene expression by plant Zn status results in the overexpression of this transporter and in increased Zn influx in roots of the hyperaccumulating Thlaspi species. These findings yield insights into the molecular regulation and control of plant heavy metal and micronutrient accumulation and homeostasis, as well as provide information that will contribute to the advancement of phytoremediation by the future engineering of plants with improved heavy metal uptake and tolerance. PMID:10781104

  8. IDENTIFICATION AND CHARACTERIZATION OF A HEAVY METAL TRANSPORTING P-TYPE ATPASE FROM THE METAL HYPERACCUMULATING PLANT SPECIES, THLASPI CAERULESCENS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thlaspi caerulescens is a Zn/Cd-hyperaccumulating plant species that can accumulate and tolerate up to30,000 ppm Zn and 4,000 ppm Cd in the shoots without exhibiting toxicity symptoms. As part of an overall program aimed at elucidating the molecular and physiological mechanisms of heavy metal hypera...

  9. SHOOT BIOMASS AND ZINC/CADMIUM UPTAKE FOR HYPERACCUMULATOR AND NON-ACCUMULATOR THLASPI SPECIES IN RESPONSE TO GROWTH ON A ZINC-DEFICIENT CALCAREOUS SOIL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, the Zn/Cd hyperaccumulator, Thlaspi caerulescens and a related non-accumulator, Thlaspi arvense, were used to study shoot growth (dry matter production) and Zn and Cd uptake from a severely Zn-deficient calcareous soil supplemented with increasing amounts of Zn and Cd. Shoot dry matte...

  10. Zinc ligands in the metal hyperaccumulator Thlaspi caerulescens as determined using X-ray absorption spectroscopy

    SciTech Connect

    Salt, D.E.; Prince, R.C.; Baker, A.J.M.; Raskin, I.; Pickering, I.J.

    1999-03-01

    Using the noninvasive technique of X-ray absorption spectroscopy (XAS), the authors have been able to determine the ligand environment of Zn in different tissues of the Zn-hyperaccumulator Thlaspi caerulescens. The majority of intracellular Zn in roots of T. caerulescens was found to be coordinated with histidine. In the xylem sap Zn was found to be transported mainly as the free hydrated Zn{sup 2+} cation with a smaller proportion coordinated with organic acids. In the shoots, Zn coordination occurred mainly via organic acids, with a smaller proportion present as the hydrated cation and coordinated with histidine and the cell wall. Their data suggest that histidine plays an important role in Zn homeostasis in the roots, whereas organic acids are involved in xylem transport and Zn storage in shoots.

  11. QTL analysis of cadmium and zinc accumulation in the heavy metal hyperaccumulator Thlaspi caerulescens.

    PubMed

    Deniau, A X; Pieper, B; Ten Bookum, W M; Lindhout, P; Aarts, M G M; Schat, H

    2006-09-01

    Thlaspi caerulescens (Tc; 2n = 14) is a natural Zn, Cd and Ni hyperaccumulator species belonging to the Brassicaceae family. It shares 88% DNA identity in the coding regions with Arabidopsis thaliana (At) (Rigola et al. 2006). Although the physiology of heavy metal (hyper)accumulation has been intensively studied, the molecular genetics are still largely unexplored. We address this topic by constructing a genetic map based on AFLP markers and expressed sequence tags (ESTs). To establish a genetic map, an F(2) population of 129 individuals was generated from a cross between a plant from a Pb/Cd/Zn-contaminated site near La Calamine, Belgium, and a plant from a comparable site near Ganges (GA), France. These two accessions show different degrees of Zn and, particularly, Cd accumulation. We analyzed 181 AFLP markers (of which 4 co-dominant) and 13 co-dominant EST sequences-based markers and mapped them to seven linkage groups (LGs), presumably corresponding to the seven chromosomes of T. caerulescens. The total length of the genetic map is 496 cM with an average density of one marker every 2.5 cM. This map was used for Quantitative Trait Locus (QTL) mapping in the F(2). For Zn as well as Cd concentration in root we mapped two QTLs. Three QTLs and one QTL were mapped for Zn and Cd concentration in shoot, respectively. These QTLs explain 23.8-60.4% of the total variance of the traits measured. We found only one common locus (LG6) for Zn and Cd (concentration in root) and one common locus for shoot and root concentrations of Zn (LG1) and of Cd (LG3). For all QTLs, the GA allele increased the trait value except for two QTLs for Zn accumulation in shoot (LG1 and LG4) and one for Zn concentration in root (LG1). PMID:16850314

  12. Transcriptional regulation of metal transport genes and mineral nutrition during acclimation to cadium and zinc in the Cd/Zn hyperaccumulator, Thlaspi caerulescens (Ganges population)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated changes in mineral nutrient uptake and cellular expression levels of metal transporter genes using the Cd/Zn hyperaccumulator Thlaspi caerulescens. We analyzed those changes genesis under different long-term (one year) treatments of the plants with zinc and cadmium using quantitative...

  13. American Journal of Botany 85(2): 259265. 1998. NICKEL HYPERACCUMULATION BY THLASPI MONTANUM

    E-print Network

    Boyd, Robert S.

    a species. Nickel hyperaccumulation is viewed as an adaptation to high-Ni (serpentine) soils, but few this question. Seed sources were from four populations (two serpentine, two non-serpentine) in Oregon growing on non- serpentine soil. This adaptive value may be a consequence of metal-based plant defense

  14. Identification of Thlaspi caerulescens Genes That May Be Involved in Heavy Metal Hyperaccumulation and Tolerance. Characterization of a Novel Heavy Metal Transporting ATPase1

    PubMed Central

    Papoyan, Ashot; Kochian, Leon V.

    2004-01-01

    Thlaspi caerulescens is a heavy metal hyperaccumulator plant species that is able to accumulate extremely high levels of zinc (Zn) and cadmium (Cd) in its shoots (30,000 ?g g?1 Zn and 10,000 ?g g?1 Cd), and has been the subject of intense research as a model plant to gain a better understanding of the mechanisms of heavy metal hyperaccumulation and tolerance and as a source of genes for developing plant species better suited for the phytoremediation of metal-contaminated soils. In this study, we report on the results of a yeast (Saccharomyces cerevisae) complementation screen aimed at identifying candidate heavy metal tolerance genes in T. caerulescens. A number of Thlaspi genes that conferred Cd tolerance to yeast were identified, including possible metal-binding ligands from the metallothionein gene family, and a P-type ATPase that is a member of the P1B subfamily of purported heavy metal-translocating ATPases. A detailed characterization of the Thlaspi heavy metal ATPase, TcHMA4, demonstrated that it mediates yeast metal tolerance via active efflux of a number of different heavy metals (Cd, Zn, lead [Pb], and copper [Cu]) out of the cell. However, in T. caerulescens, based on differences in tissue-specific and metal-responsive expression of this transporter compared with its homolog in Arabidopsis (Arabidopsis thaliana), we suggest that it may not be involved in metal tolerance. Instead, we hypothesize that it may play a role in xylem loading of metals and thus could be a key player in the hyperaccumulation phenotype expressed in T. caerulescens. Additionally, evidence is presented showing that the C terminus of the TcHMA4 protein, which contains numerous possible heavy metal-binding His and Cys repeats residues, participates in heavy metal binding. When partial peptides from this C-terminal domain were expressed in yeast, they conferred an extremely high level of Cd tolerance and Cd hyperaccumulation. The possibilities for enhancing the metal tolerance and phytoremediation potential of higher plants via expression of these metal-binding peptides are also discussed. PMID:15516513

  15. Investigation of Heavy Metal Hyperaccumulation at the Cellular Level: Development and Characterization of Thlaspi caerulescens Suspension Cell Lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ability of metal hyperaccumulator plant species to accumulate high concentrations of toxic heavy metals requires the coordinated uptake, transport and sequestration of these metals to avoid damage to photosynthetic mechanisms. A number of previous studies have examined how hyperaccumulating pla...

  16. Cadmium sorption, influx, and efflux at the mesophyll layer of leaves from ecotypes of the Zn/Cd hyperaccumulator Thlaspi caerulescens

    SciTech Connect

    Ebbs, S.D.; Zambrano, M.C.; Spiller, S.M.; Newville, M.

    2009-01-23

    Differential sorption and transport characteristics of the leaf mesophyll layer of the Prayon and Ganges ecotypes of the hyperaccumulator Thlaspi caerulescens were examined. {sup 109}Cd influx and efflux experiments were conducted with leaf sections, and X-ray absorption near edge structure (XANES) data were collected from leaves as a general comparison of in vivo cadmium (Cd) coordination. There were modest differences in cell wall sorption of Cd between ecotypes. There were obvious differences in time- and concentration-dependent Cd influx, including a greater V{sub MAX} for Prayon but a lower K{sub M} for Ganges for concentration-dependent Cd uptake and a notably greater Cd uptake by Ganges leaf sections at 1000 {micro}m Cd. Leaf sections of Prayon had a greater Cd efflux than Ganges. The XANES spectra from the two ecotypes suggested differences in Cd coordination. The fundamental differences observed between the two ecotypes may reflect differential activity and/or expression of plasma membrane and tonoplast transporters. More detailed study of these transporters and the in vivo coordination of Cd are needed to determine the contribution of these processes to metal homeostasis and tolerance.

  17. Metallothioneins 2 and 3 contribute to the metal-adapted phenotype but are not directly linked to Zn accumulation in the metal hyperaccumulator, Thlaspi caerulescens.

    PubMed

    Hassinen, V H; Tuomainen, M; Peräniemi, S; Schat, H; Kärenlampi, S O; Tervahauta, A I

    2009-01-01

    To study the role of metallothioneins (MTs) in Zn accumulation, the expression of TcMT2a, TcMT2b, and TcMT3 was analysed in three accessions and 15 F(3) families of two inter-accession crosses of the Cd/Zn hyperaccumulator Thlaspi caerulescens, with different degrees of Zn accumulation. The highest expression levels were found in the shoots of a superior metal-accumulating calamine accession from St Laurent le Minier, with >10-fold TcMT3 expression compared with another calamine accession and a non-metallicolous accession. Moreover, F(3) sibling lines from the inter-accession crosses that harboured the MT2a or MT3 allele from St Laurent le Minier had higher expression levels. However, there was no co-segregation of TcMT2a or TcMT3 expression and Zn accumulation. To examine the functions of TcMTs in plants, TcMT2a and TcMT3 were ectopically expressed in Arabidopsis. The transformant lines had reduced root length in control medium but not at high metal concentrations, suggesting that the ectopically expressed proteins interfered with the physiological availability of essential metals under limited supply. The Arabidopsis transformant lines did not show increased tolerance to Cd, Cu, or Zn, nor increased Cd or Zn accumulation. Immunohistochemical analysis indicated that in roots, MT2 protein is localized in the epidermis and root hairs of both T. caerulescens and Arabidopsis thaliana. The results suggest that TcMT2a, TcMT2b, and TcMT3 are not primarily involved in Zn accumulation as such. However, the elevated expression levels in the metallicolous accessions suggests that they do contribute to the metal-adapted phenotype, possibly through improving Cu homeostasis at high Zn and Cd body burdens. Alternatively, they might function as hypostatic enhancers of Zn or Cd tolerance. PMID:19033549

  18. Comparison of two ecotypes of the metal hyperaccumulator Thlaspi caerulescens (J. & C. PRESL) at the transcriptional level.

    PubMed

    Plessl, Markus; Rigola, Diana; Hassinen, Viivi H; Tervahauta, Arja; Kärenlampi, Sirpa; Schat, Henk; Aarts, Mark G M; Ernst, Dieter

    2010-03-01

    This paper investigates differences in gene expression among the two Thlaspi caerulescens ecotypes La Calamine (LC) and Lellingen (LE) that have been shown to differ in metal tolerance and metal uptake. LC originates from a metalliferous soil and tolerates higher metal concentrations than LE which originates from a non-metalliferous soil. The two ecotypes were treated with different levels of zinc in solution culture, and differences in gene expression were assessed through application of a cDNA microarray consisting of 1,700 root and 2,700 shoot cDNAs. Hybridisation of root and shoot cDNA from the two ecotypes revealed a total of 257 differentially expressed genes. The regulation of selected genes was verified by quantitative reverse transcriptase polymerase chain reaction. Comparison of the expression profiles of the two ecotypes suggests that LC has a higher capacity to cope with reactive oxygen species and to avoid the formation of peroxynitrite. Furthermore, increased transcripts for the genes encoding for water channel proteins could explain the higher Zn tolerance of LC compared to LE. The higher Zn tolerance of LC was reflected by a lower expression of the genes involved in disease and defence mechanisms. The results of this study provide a valuable set of data that may help to improve our understanding of the mechanisms employed by plants to tolerate toxic concentrations of metal in the soil. PMID:19937357

  19. CREATION AND CHARACTERIZATION OF THLASPI CAERULESCENS AND THLASPI ARVENSE SUSPENSION CELL LINES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thlaspi caerulescens is a zinc and cadmium hyperaccumulator, capable of storing up to 30,000 ppm Zn or 10,000 ppm Cd in the shoots without exhibiting toxicity symptoms. Previous research demonstrates the heavy metal hyperaccumulation seen in T. caerulescens is due to altered regulation of uptake, tr...

  20. The effect of plant cadmium and zinc status on root and shoot heavy metal accumulation in the heavy metal hyperaccumulator, Thlaspi caerulescens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thlaspi caerulescens is a plant species capable of tolerating and accumulating extremely high concentrations of the heavy metals, Zn and Cd, in the shoot. In this study, we investigated the impact of changes in plant heavy metal status (i.e. Zn and Cd) on the accumulation of heavy metals, including...

  1. Elevated expression of TcHMA3 plays a key role in the extreme Cd tolerance exhibited by a Cd-hyperaccumulating ecotype of Thlaspi caerulescens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cadmium (Cd) is a highly toxic heavy metal for plants, but several unique Cd hyperaccumulating plant species are able to accumulate this metal to extraordinary concentrations in the above-ground tissues without showing any toxic symptoms. However, the molecular mechanisms underlying this hyper-tole...

  2. POTENTIAL FOR GENETIC IMPROVEMENT OF THLASPI CAERULESCENS FOR PHYTOREMEDIATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thlaspi caerulescens has excellent potential to be used for remediation of zinc and cadmium polluted soils. Although plants of this species have been found to consistently hyperaccumulate cadmium and zinc, the levels of cadmium and zinc that individual plants accumulate depend on their genotype and...

  3. DIFFERENCES IN WHOLE CELL AND SINGLE CHANNEL ION CURRENTS ACROSS THE PLASMA MEMBRANE OF MESOPHYLL CELLS FROM TWO CLOSELY RELATED THLASPI SPECIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The patch clamp technique was used to study the physiology of ion transport in mesophyll cells from Thlaspi caerulescens, a heavy metal (Zn/Cd) hyperaccumulator species that can tolerate and accumulate very high levels of heavy metals in their leaf cells, and Thlaspi arvense, a related non-accumulat...

  4. EXPRESSION PROFILING OF ZN AND OTHER METAL RELATED GENES IN THLASPI CAERULESCENS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous research has shown that Thlaspi caerulescens is able to hyperaccumulate as much as 30,000 ppm zinc and 10,000 ppm cadmium in its shoots. In an attempt to better understand the ability of this plant to tolerate and accumulate such high levels of toxic metals, we looked at the expression of g...

  5. Molecular dissection of the cellular mechanisms involved in nickel hyperaccumulation in plants. 1998 annual progress report

    SciTech Connect

    Salt, D.

    1998-06-01

    'Phytoremediation, the use of plants for environmental cleanup of pollutants, including toxic metals, holds the potential to allow the economic restoration of heavy metal and radionuclide contaminated sites. A number of terrestrial plants are known to naturally accumulate high levels of metals in their shoots (1--2% dry weight), and these plants have been termed metal-hyperaccumulators. Clearly, the genetic traits that determine metal-hyperaccumulation offers the potential for the development of practical phytoremediation processes. The long-term objective is to rationally design and generate plants ideally suited for phytoremediation using this unique genetic material. Initially, the strategy will focus on isolating and characterizing the key genetic information needed for expression of the metal-hyperaccumulation phenotype. Recently, histidine has been shown to play a major role in Ni hyperaccumulation. Based on this information the authors propose to investigate, at the molecular level, the role of histidine biosynthesis in Ni hyperaccumulation in Thlaspi goesingense, a Ni hyperaccumulator species.'

  6. A native Zn/Cd transporting P1B ATPase from natural overexpression in a hyperaccumulator plant reveals post-translational processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    TcHMA4 is a P1B-type ATPase that is highly expressed in the Cd/Zn hyperaccumulator plant Thlaspi caerulescens and contains a C-terminal 9-histidine repeat. After isolation from roots, we purified TcHMA4 protein via metal affinity chromatography. The purified protein exhibited Cd- and Zn activated AT...

  7. Proteomics of Thlaspi caerulescens accessions and an inter-accession cross segregating for zinc accumulation

    PubMed Central

    Tuomainen, Marjo; Tervahauta, Arja; Hassinen, Viivi; Schat, Henk; Koistinen, Kaisa M.; Lehesranta, Satu; Rantalainen, Kimmo; Häyrinen, Jukka; Auriola, Seppo; Anttonen, Mikko; Kärenlampi, Sirpa

    2010-01-01

    Metal hyperaccumulator plants have previously been characterized by transcriptomics, but reports on other profiling techniques are scarce. Protein profiles of Thlaspi caerulescens accessions La Calamine (LC) and Lellingen (LE) and lines derived from an LC×LE cross were examined here to determine the co-segregation of protein expression with the level of zinc (Zn) hyperaccumulation. Although hydrophobic proteins such as membrane transporters are not disclosed, this approach has the potential to reveal other proteins important for the Zn hyperaccumulation trait. Plants were exposed to metals. Proteins were separated using two-dimensional electrophoresis and those showing differences among accessions, lines or metal exposures were subjected to mass-spectrometric analysis for identification. Crossing decreased the number of different proteins in the lines compared with the parents, more so in the shoots than in the roots, but the frequencies of Zn-responsive proteins were about the same in the accessions and the selection lines. This supports the finding that the Zn accumulation traits are mainly determined by the root and that Zn accumulation itself is not the reason for the co-segregation. This study demonstrates that crossing accessions with contrasting Zn accumulation traits is a potent tool to investigate the mechanisms behind metal hyperaccumulation. Four tentatively identified root proteins showed co-segregation with high or low Zn accumulation: manganese superoxide dismutase, glutathione S-transferase, S-formyl glutathione hydrolase, and translation elongation factor 5A-2. However, these proteins may not be the direct determinants of Zn accumulation. The role of these and other tentatively identified proteins in Zn accumulation and tolerance is discussed. PMID:20048332

  8. Proteomics of Thlaspi caerulescens accessions and an inter-accession cross segregating for zinc accumulation.

    PubMed

    Tuomainen, Marjo; Tervahauta, Arja; Hassinen, Viivi; Schat, Henk; Koistinen, Kaisa M; Lehesranta, Satu; Rantalainen, Kimmo; Häyrinen, Jukka; Auriola, Seppo; Anttonen, Mikko; Kärenlampi, Sirpa

    2010-02-01

    Metal hyperaccumulator plants have previously been characterized by transcriptomics, but reports on other profiling techniques are scarce. Protein profiles of Thlaspi caerulescens accessions La Calamine (LC) and Lellingen (LE) and lines derived from an LCxLE cross were examined here to determine the co-segregation of protein expression with the level of zinc (Zn) hyperaccumulation. Although hydrophobic proteins such as membrane transporters are not disclosed, this approach has the potential to reveal other proteins important for the Zn hyperaccumulation trait. Plants were exposed to metals. Proteins were separated using two-dimensional electrophoresis and those showing differences among accessions, lines or metal exposures were subjected to mass-spectrometric analysis for identification. Crossing decreased the number of different proteins in the lines compared with the parents, more so in the shoots than in the roots, but the frequencies of Zn-responsive proteins were about the same in the accessions and the selection lines. This supports the finding that the Zn accumulation traits are mainly determined by the root and that Zn accumulation itself is not the reason for the co-segregation. This study demonstrates that crossing accessions with contrasting Zn accumulation traits is a potent tool to investigate the mechanisms behind metal hyperaccumulation. Four tentatively identified root proteins showed co-segregation with high or low Zn accumulation: manganese superoxide dismutase, glutathione S-transferase, S-formyl glutathione hydrolase, and translation elongation factor 5A-2. However, these proteins may not be the direct determinants of Zn accumulation. The role of these and other tentatively identified proteins in Zn accumulation and tolerance is discussed. PMID:20048332

  9. Comparative transcriptome analysis of the metal hyperaccumulator Noccaea caerulescens

    PubMed Central

    Halimaa, Pauliina; Blande, Daniel; Aarts, Mark G. M.; Tuomainen, Marjo; Tervahauta, Arja; Kärenlampi, Sirpa

    2014-01-01

    The metal hyperaccumulator Noccaea caerulescens is an established model to study the adaptation of plants to metalliferous soils. Various comparators have been used in these studies. The choice of suitable comparators is important and depends on the hypothesis to be tested and methods to be used. In high-throughput analyses such as microarray, N. caerulescens has been compared to non-tolerant, non-accumulator plants like Arabidopsis thaliana or Thlaspi arvense rather than to the related hypertolerant or hyperaccumulator plants. An underutilized source is N. caerulescens populations with considerable variation in their capacity to accumulate and tolerate metals. Whole transcriptome sequencing (RNA-Seq) is revealing interesting variation in their gene expression profiles. Combining physiological characteristics of N. caerulescens accessions with their RNA-Seq has a great potential to provide detailed insight into the underlying molecular mechanisms, including entirely new gene products. In this review we will critically consider comparative transcriptome analyses carried out to explore metal hyperaccumulation and hypertolerance of N. caerulescens, and demonstrate the potential of RNA-Seq analysis as a tool in evolutionary genomics. PMID:24904610

  10. Molecular dissection of the cellular mechanisms involved in nickel hyperaccumulation. 1997 annual progress report

    SciTech Connect

    Salt, D.E.

    1997-10-28

    'Phytoremediation, the use of plants for environmental cleanup of pollutants, including toxic metals, holds the potential to allow the economic restoration of heavy metal and radionuclide contaminated sites. A number of terrestrial plants are known to naturally accumulate high levels of metals in their shoots (1--2% dry weight), and these plants have been termed metal-hyperaccumulators. Clearly, the genetic traits that determine metal-hyperaccumulation offers the potential for the development of practical phytoremediation processes. The long-term objective is to rationally design and generate plants ideally suited for phytoremediation using this unique genetic material. Initially, the strategy will focus on isolating and characterizing the key genetic information needed for expression of the metal-hyperaccumulation phenotype. Recently, histidine has been shown to play a major role in Ni hyperaccumulation. Based on this information the authors propose to investigate, at the molecular level, the role of histidine biosynthesis in Ni hyperaccumuIation in Thlaspi goesingense, a Ni hyperaccumulator species.'

  11. Molecular dissection of the role of histidine in nickel hyperaccumulation in Thalspi goesingense (Halacsy)

    SciTech Connect

    Persans, M.W.; Yan, X.; Patnoe, J.M.M.L.; Kraemer, U.; Salt, D.E.

    1999-12-01

    To understand the role of free histidine (His) in Ni hyperaccumulation in Thlaspi goesingense, the authors investigated the regulation of His biosynthesis at both the molecular and biochemical levels. Three T. goesingense cDNAs encoding the following His biosynthetic enzymes, ATP phosphoribosyltransferase, imidazoleglycerol phosphate dehydratase, and histidinol dehydrogenase, were isolated by functional complementation of Escherichia coli His autotrophs. Northern analysis of THJG1, THD1, and THB1 gene expression revealed that each gene is expressed in both roots and shoots, but at the concentrations and dosage times of Ni treatment used in this study, these genes failed to show any regulation by Ni. The authors were also unable to observe any increases in the concentration of free His in root, shoot, or xylem sap of T. goesingense in response to Ni exposure. X-ray absorption spectroscopy of root and shoot tissue from T. goesingense and the non-accumulator species Thlaspi reverse revealed no major differences in the coordination of Ni by His in these tissues. They therefore conclude that the Ni hyperaccumulation phenotype in T. goesingense is not determined by the overproduction of His in response to Ni.

  12. Construction of a genetic linkage map of Thlaspi caerulescens and quantitative trait loci analysis of zinc accumulation.

    PubMed

    Assunção, Ana G L; Pieper, Bjorn; Vromans, Jaap; Lindhout, Pim; Aarts, Mark G M; Schat, Henk

    2006-01-01

    Zinc (Zn) hyperaccumulation seems to be a constitutive species-level trait in Thlaspi caerulescens. When compared under conditions of equal Zn availability, considerable variation in the degree of hyperaccumulation is observed among accessions originating from different soil types. This variation offers an excellent opportunity for further dissection of the genetics of this trait. A T. caerulescens intraspecific cross was made between a plant from a nonmetallicolous accession [Lellingen (LE)], characterized by relatively high Zn accumulation, and a plant from a calamine accession [La Calamine (LC)], characterized by relatively low Zn accumulation. Zinc accumulation in roots and shoots segregated in the F3 population. This population was used to construct an LE/LC amplified fragment length polymorphism (AFLP)-based genetic linkage map and to map quantitative trait loci (QTL) for Zn accumulation. Two QTL were identified for root Zn accumulation, with the trait-enhancing alleles being derived from each of the parents, and explaining 21.7 and 16.6% of the phenotypic variation observed in the mapping population. Future development of more markers, based on Arabidopsis orthologous genes localized in the QTL regions, will allow fine-mapping and map-based cloning of the genes underlying the QTL. PMID:16539600

  13. MODE OF POLLINATION IN TWO THLASPI CAERULESCENS POPULATIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thlaspi caerulescens, formerly known as T. alpestre, has been reported to be self-pollinated. Among T. alpestre plants, Riley (1956) found only 5.25 % outcrossing, whereas Holmgren (1971) found a range of 5-35% outcrossing. These studies suggest that T. caerulescens plants are predominantly self-p...

  14. Culturable endophytic bacteria enhance Ni translocation in the hyperaccumulator Noccaea caerulescens.

    PubMed

    Visioli, Giovanna; D'Egidio, Sara; Vamerali, Teofilo; Mattarozzi, Monica; Sanangelantoni, Anna Maria

    2014-12-01

    In this work, both culture-dependent and independent approaches were used to identify and isolate endophytic bacteria from roots of the Ni hyperaccumulator Noccaea caerulescens. A total of 17 isolates were cultured from root samples, selected for tolerance to 6mM Ni and grouped by restriction analysis of 16S rDNA. Bacterial species cultivated from roots belonged to seven genera, Microbacterium, Arthrobacter, Agreia, Bacillus, Sthenotrophomonas, Kocuria and Variovorax. The culture-independent approach confirmed the presence of Microbacterium and Arthrobacter while only other five clones corresponding to different amplified ribosomal DNA restriction patterns were detected. Five selected highly Ni-resistant bacteria showing also plant growth promoting activities, were inoculated into seeds of N. caerulescens, and in vivo microscopic analysis showed rapid root colonisation. Inoculated plants showed increased shoot biomass, root length and root-to-shoot Ni translocation. Root colonisation was also evident, but not effective, in the non-hyperaccumulating Thlaspi perfoliatum. Seed inoculation with selected Ni-resistant endophytic bacteria may represent a powerful tool in phytotechnologies, although transferring it to biomass species still requires further studies and screening. PMID:25277966

  15. ENDEMISM VS INVASIBILITY IN NICKEL HYPERACCUMULATORS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several species of nickel hyperaccumulators in the genus Alyssum are found on serpentine (ultramafic) soils throughout southern and eastern Europe and Asia, and some are endemic to serpentine substrates. This study examines the extent to which physiological factors restrict nickel hyperaccumulators ...

  16. Compartmentation and complexation of metals in hyperaccumulator plants

    PubMed Central

    Leitenmaier, Barbara; Küpper, Hendrik

    2013-01-01

    Hyperaccumulators are being intensely investigated. They are not only interesting in scientific context due to their “strange” behavior in terms of dealing with high concentrations of metals, but also because of their use in phytoremediation and phytomining, for which understanding the mechanisms of hyperaccumulation is crucial. Hyperaccumulators naturally use metal accumulation as a defense against herbivores and pathogens, and therefore deal with accumulated metals in very specific ways of complexation and compartmentation, different from non-hyperaccumulator plants and also non-hyperaccumulated metals. For example, in contrast to non-hyperaccumulators, in hyperaccumulators even the classical phytochelatin-inducing metal, cadmium, is predominantly not bound by such sulfur ligands, but only by weak oxygen ligands. This applies to all hyperaccumulated metals investigated so far, as well as hyperaccumulation of the metalloid arsenic. Stronger ligands, as they have been shown to complex metals in non-hyperaccumulators, are in hyperaccumulators used for transient binding during transport to the storage sites (e.g., nicotianamine) and possibly for export of Cu in Cd/Zn hyperaccumulators [metallothioneins (MTs)]. This confirmed that enhanced active metal transport, and not metal complexation, is the key mechanism of hyperaccumulation. Hyperaccumulators tolerate the high amount of accumulated heavy metals by sequestering them into vacuoles, usually in large storage cells of the epidermis. This is mediated by strongly elevated expression of specific transport proteins in various tissues from metal uptake in the shoots up to the storage sites in the leaf epidermis. However, this mechanism seems to be very metal specific. Non-hyperaccumulated metals in hyperaccumulators seem to be dealt with like in non-hyperaccumulator plants, i.e., detoxified by binding to strong ligands such as MTs. PMID:24065978

  17. RESEARCH ARTICLE Open Access Selenium hyperaccumulation offers protection

    E-print Network

    RESEARCH ARTICLE Open Access Selenium hyperaccumulation offers protection from cell disruptor that selenium (Se) hyperaccumulation protects plants from a variety of herbivores and pathogens. Selenium herbivores. Selenium distribution and speciation studies using micro- focused X-ray fluorescence (XRF

  18. REGULAR ARTICLE Enhanced decomposition of selenium hyperaccumulator litter

    E-print Network

    REGULAR ARTICLE Enhanced decomposition of selenium hyperaccumulator litter in a seleniferous-Smits # Springer Science+Business Media B.V. 2010 Abstract Selenium (Se) hyperaccumulation, when plant species

  19. Production and Evaluation of Biodiesel from Field Pennycress (Thlaspi Arvense L.) Oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field pennycress (Thlaspi arvense L.) oil is evaluated for the first time as a potential feedstock for biodiesel production. Biodiesel was obtained in 82 wt % yield by a standard transesterification procedure with methanol and sodium methoxide catalyst at 60 deg C and an alcohol to oil ratio of 6:1...

  20. Composition and functional properties of protein recovered from pennycreess (Thlaspi arvense) press cake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress (Thlaspi arvense L.) seed oil is being considered as alternative feedstock for biodiesel production. If the pennycress-based biodiesel venture is successful, then the seed protein (more than 20% content) could become a major co-product of the process. This study compared two methods for e...

  1. Field Pennycress (Thlaspi arvense L.) Oil: A Promising Source of Biodiesel.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field pennycress (Thlaspi arvense L., FP) is a winter annual species of the mustard family (Brassicaceae) that is widely distributed throughout temperate North America and which can serve in a winter rotational cycle with conventional crops, thus not displacing existing agricultural production or ne...

  2. Genome Structure of the Heavy Metal Hyperaccumulator Noccaea caerulescens and Its Stability on Metalliferous and Nonmetalliferous Soils1[OPEN

    PubMed Central

    Mandáková, Terezie; Singh, Vasantika; Krämer, Ute; Lysak, Martin A.

    2015-01-01

    Noccaea caerulescens (formerly known as Thlaspi caerulescens), an extremophile heavy metal hyperaccumulator model plant in the Brassicaceae family, is a morphologically and phenotypically diverse species exhibiting metal tolerance and leaf accumulation of zinc, cadmium, and nickel. Here, we provide a detailed genome structure of the approximately 267-Mb N. caerulescens genome, which has descended from seven chromosomes of the ancestral proto-Calepineae Karyotype (n = 7) through an unusually high number of pericentric inversions. Genome analysis in two other related species, Noccaea jankae and Raparia bulbosa, showed that all three species, and thus probably the entire Coluteocarpeae tribe, have descended from the proto-Calepineae Karyotype. All three analyzed species share the chromosome structure of six out of seven chromosomes and an unusually high metal accumulation in leaves, which remains moderate in N. jankae and R. bulbosa and is extreme in N. caerulescens. Among these species, N. caerulescens has the most derived karyotype, with species-specific inversions on chromosome NC6, which grouped onto its bottom arm functionally related genes of zinc and iron metal homeostasis comprising the major candidate genes NICOTIANAMINE SYNTHASE2 and ZINC-INDUCED FACILITATOR-LIKE1. Concurrently, copper and organellar metal homeostasis genes, which are functionally unrelated to the extreme traits characteristic of N. caerulescens, were grouped onto the top arm of NC6. Compared with Arabidopsis thaliana, more distal chromosomal positions in N. caerulescens were enriched among more highly expressed metal homeostasis genes but not among other groups of genes. Thus, chromosome rearrangements could have facilitated the evolution of enhanced metal homeostasis gene expression, a known hallmark of metal hyperaccumulation. PMID:26195571

  3. Effects of arsenic on nitrate metabolism in arsenic hyperaccumulating and non-hyperaccumulating ferns

    E-print Network

    Ma, Lena

    Effects of arsenic on nitrate metabolism in arsenic hyperaccumulating and non Arsenic reduced the activity of nitrate and nitrite reductase more in Pteris ensiformis than Pteris March 2009 Accepted 26 March 2009 Keywords: Arsenic Nitrate metabolism Pteris vittata Arsenic

  4. Interactions of selenium hyperaccumulators and nonaccumulators during cocultivation on seleniferous or

    E-print Network

    Interactions of selenium hyperaccumulators and nonaccumulators during cocultivation on seleniferous, hyperaccumulation, phytoenrichment, plant­plant interactions, selenium, Stanleya. Summary · This study investigated how selenium (Se) affects relationships between Se hyperaccumulator and nonaccumulator species

  5. Evolution of selenium hyperaccumulation in Stanleya (Brassicaceae) as inferred from phylogeny, physiology and X-ray

    E-print Network

    Evolution of selenium hyperaccumulation in Stanleya (Brassicaceae) as inferred from phylogeny words: ancestral reconstruction, evolution, hyperaccumulation, phylogenetics, selenium (Se), Stanleya, X context. We focused on the evolutionary history of selenium (Se) hyperaccumulation in Stanleya

  6. Interactions of selenium hyperaccumulators and nonaccumulators during cocultivation on seleniferous or

    E-print Network

    Interactions of selenium hyperaccumulators and nonaccumulators during cocultivation on seleniferous: Astragalus, hyperaccumulation, phytoenrichment, plant­plant interactions, selenium, Stanleya. Summary · This study investigated how selenium (Se) affects relationships between Se hyperaccumulator

  7. MICROSPECTROSCOPIC STUDY OF COBALT SPECIATION AND LOCALIZATION IN HYPERACCUMULATOR ALYSSUM MURALE

    E-print Network

    Sparks, Donald L.

    MICROSPECTROSCOPIC STUDY OF COBALT SPECIATION AND LOCALIZATION IN HYPERACCUMULATOR ALYSSUM MURALE MICROSPECTROSCOPIC STUDY OF COBALT SPECIATION AND LOCALIZATION IN HYPERACCUMULATOR ALYSSUM MURALE by Ryan V. Tappero

  8. Prospecting for hyperaccumulators of trace elements: a review.

    PubMed

    Krzciuk, Karina; Ga?uszka, Agnieszka

    2015-12-01

    Specific plant species that can take up and accumulate abnormally high concentrations of elements in their aboveground tissues are referred to as "hyperaccumulators". The use of this term is justified in the case of enormous element-binding capacity of plants growing in their natural habitats and showing no toxicity symptoms. An increasing interest in the study of hyperaccumulators results from their potential applications in environmental biotechnology (phytoremediation, phytomining) and their emerging role in nanotechnology. The highest number of plant species with confirmed hyperaccumulative properties has been reported for hyperaccumulators of nickel, cadmium, zinc, manganese, arsenic and selenium. More limited data exist for plants accumulating other elements, including common pollutants (chromium, lead and boron) or elements of commercial value, such as copper, gold and rare earth elements. Different approaches have been used for the study of hyperaccumulators - geobotanical, chemical, biochemical and genetic. The chemical approach is the most important in screening for new hyperaccumulators. This article presents and critically reviews current trends in new hyperaccumulator research, emphasizing analytical methodology that is applied in identification of new hyperaccumulators of trace elements and its future perspectives. PMID:24938121

  9. XAS Speciation of Arsenic in a Hyper-Accumulating Fern

    E-print Network

    Ma, Lena

    XAS Speciation of Arsenic in a Hyper-Accumulating Fern S A M U E L M . W E B B , J E A N - F R A N environment and the redox speciation of arsenic in a newly discovered arsenic hyper-accumulating fern (Pteris high As concentrations (ca. 1% As per dry weight) arsenic in the fern leaves is coordinated

  10. SOIL MICROBIAL EFFECTS ON HEAVY METAL UPTAKE INTO HYPERACCUMULATORS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Uptake of heavy metals into hyperaccumulators is influenced by a number of chemical, physical and biological factors. Of these, recent evidence has shown that microbes living within the rhizosphere of hyperaccumulators may have a significant effect on metal uptake. Much is known about the role my...

  11. Effects of arsenic on nitrogen metabolism in arsenic hyperaccumulator and non-hyperaccumulator ferns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the effects of arsenic on the in vitro activities of the enzymes (nitrate reductase and nitrite reductase) involved in nitrate metabolism in the roots, rhizomes, and fronds of two four-month old fern plants, Pteris vittata, an arsenic-hyperaccumulator, and Pteris ensiformis, ...

  12. Molecular mechanisms of selenium tolerance and hyperaccumulation in Stanleya pinnata John L. Freeman1,2,3

    E-print Network

    2 Title: Molecular mechanisms of selenium tolerance and hyperaccumulation in Stanleya pinnata;3 Abstract The molecular mechanisms responsible for selenium (Se) tolerance and hyperaccumulation were hyperaccumulation of S. pinnata perhaps by constitutively up-regulating sulfur/selenium assimilation followed

  13. Effects of oil extraction on functional properties of protein in pennycress (Thlaspi arvense) seed and press cake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current interest in pennycress (Thlaspi arvense) comes from its seed oil, which is being evaluated for biodiesel production. The seed also has notable protein content (33% db). The effects of oil processing conditions on functionality of pennycress seed proteins were determined to identify potential...

  14. REGULAR ARTICLE Enhanced decomposition of selenium hyperaccumulator litter

    E-print Network

    REGULAR ARTICLE Enhanced decomposition of selenium hyperaccumulator litter in a seleniferous-Smits Received: 2 April 2010 /Accepted: 19 May 2010 # Springer Science+Business Media B.V. 2010 Abstract Selenium

  15. Arsenic speciation, and arsenic and phosphate distribution in arsenic hyperaccumulator Pteris vittata L. and

    E-print Network

    Ma, Lena

    Arsenic speciation, and arsenic and phosphate distribution in arsenic hyperaccumulator Pteris examined the roles of arsenic translocation and reduction, and P distribution in arsenic detoxification of Pteris vittata L. (Chinese Brake fern), an arsenic hyperaccumulator and Pteris ensiformis L. (Slender

  16. Arsenic species and leachability in the fronds of the hyperaccumulator Chinese brake (Pteris vittata L.)

    E-print Network

    Ma, Lena

    Arsenic species and leachability in the fronds of the hyperaccumulator Chinese brake (Pteris June 2002; accepted 9 December 2002 ``Capsule'': Arsenic was predominantly present as inorganic arsenite in the fronds of the hyperaccumulator Chinese brake. Abstract Arsenic speciation is important

  17. Effects of selenium hyperaccumulation on plantplant interactions: evidence for elemental allelopathy?

    E-print Network

    Effects of selenium hyperaccumulation on plant­plant interactions: evidence for elemental bisulcatus, hyper- accumulation, plant­plant interactions, selenium (Se), Stanleya pinnata. Summary · Few investigated the effect of selenium (Se) hyperaccumulation on neighboringplants. · Soil and litter Se

  18. ARSENIC HYPERACCUMULATION BY Pteris vittata L. AND ITS POTENTIAL FOR PHYTOREMEDIATION OF ARSENIC-CONTAMINATED SOILS

    E-print Network

    Ma, Lena

    ARSENIC HYPERACCUMULATION BY Pteris vittata L. AND ITS POTENTIAL FOR PHYTOREMEDIATION OF ARSENIC.............................................................................................4 Arsenic..........................................................................................................................4 Chemistry of Arsenic

  19. Spatial Imaging, Speciation, and Quantification of Selenium in the Hyperaccumulator Plants Astragalus

    E-print Network

    Spatial Imaging, Speciation, and Quantification of Selenium in the Hyperaccumulator Plants pinnata hyperaccumulate selenium (Se) up to 1% of plant dry weight. In the field, Se was mostly present in specific storage areas in the plant periphery appears to be a unique property of Se hyperaccumulators

  20. Selenium Distribution and Speciation in the Hyperaccumulator Astragalus bisulcatus and Associated

    E-print Network

    Selenium Distribution and Speciation in the Hyperaccumulator Astragalus bisulcatus and Associated 82007 (A.L.W.) The goal of this study was to investigate how plant selenium (Se) hyperaccumulation may influence species composition and Se cycling in seleniferous ecosystems. Selenium (Se) hyperaccumulation

  1. Selenium hyperaccumulation offers protection from cell disruptor herbivores Colin F. Quinn1,#

    E-print Network

    1 Selenium hyperaccumulation offers protection from cell disruptor herbivores Colin F. Quinn1 and pathogens. Previous research has shown that selenium (Se) hyperaccumulation protects plants from a variety of herbivores and pathogens. Selenium hyperaccumulating plants sequester Se in discrete locations in the leaf

  2. Nickel solubilizing capacity and characterization of rhizobacteria isolated from hyperaccumulating and non-hyperaccumulating subspecies of Alyssum serpyllifolium.

    PubMed

    Becerra-Castro, C; Prieto-Fernández, A; Alvarez-Lopez, V; Monterroso, C; Cabello-Conejo, M I; Acea, M J; Kidd, P S

    2011-01-01

    Bacterial strains were isolated from the rhizosphere of three populations of the Ni-hyperaccumulator Alyssum serpyllifolium subsp. lusitanicum (A. pintodasilvae; M, S, and L), one population of Ni-hyperaccumulator A. serpyllifolium subsp. malacitanum (A. malacitanum; SB), and one population of the non-hyperaccumulator A. serpyllifolium subsp. serpyllifolium (A. serpyllifolium; SN). Isolates were characterized genotypically by BOX-PCR genomic DNA fingerprinting and comparative sequence analysis of partial 16S rRNA gene, and phenotypically by their Ni tolerance (0-10 mM), presence of plant growth promoting traits (indoleacetic acid (IAA)-, siderophore-, or organic acid-production, and phosphate solubilization) or capacity to produce biosurfactants. Among the collection of rhizobacteria, 84 strains were selected (according to their BOX-PCR profiles and phenotypic characteristics) to assess their ability to modify Ni extractability from Ni-rich (serpentine) soils. Metabolites produced by 13 of the isolates mobilized soil Ni (originating from the rhizosphere of both Ni-hyperaccumulators and non-hyperaccumulator). In contrast, Ni extraction using culture medium filtrates which had supported the growth of 29 strains was significantly reduced. The remaining strains had no effect on Ni mobility. Bacterial induced Ni mobilization was not related to Ni resistance or the phenotypic traits tested. Isolates with potential use in phytoremediation techniques will be further studied in a plant-microorganism-soil system. PMID:22046762

  3. RESEARCH PAPER Antioxidant responses of hyper-accumulator and

    E-print Network

    Ma, Lena

    RESEARCH PAPER Antioxidant responses of hyper-accumulator and sensitive fern species to arsenic to examine (i) arsenic accumulation in three fern species [Chinese brake fern (Pteris vittata L.), slender brake fern (Pteris ensiformis Burm. f.), and Boston fern (Nephrolepis exaltata L.)], which were exposed

  4. Improved Understanding of Hyperaccumulation Yields Commercial Phytoextraction and Phytomining Technologies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper reviews progress in phytoextraction of soil elements and illustrates the key role of hyperaccumulator plant species in useful technologies. Much research has focused on elements which are not practically phytoextracted (Pb); on addition of chelating agents which cause unacceptable contam...

  5. Research papers Does hyperaccumulated nickel affect leaf decomposition?

    E-print Network

    Boyd, Robert S.

    factors affect the decomposition rate of plant litter (Aerts 2006): 1) climate, 2) the nature of the soilResearch papers Does hyperaccumulated nickel affect leaf decomposition? A field test using Senecio Herbarium, School of Animal and Plant Sciences, University of the Witwatersrand, Private Bag 3, WITS 2050

  6. REVIEW ARTICLE Ecological aspects of plant selenium hyperaccumulation

    E-print Network

    REVIEW ARTICLE Ecological aspects of plant selenium hyperaccumulation A. F. El Mehdawi & E. A. H.1%), manganese (Mn, >1%), nickel (Ni, >0.1%), selenium (Se, >0.1%) and zinc (Zn, >1%). The element levels accumu system. Selenium naturally occurs as a trace element in most soils. Soil Se levels are typically below 1

  7. Forms of Zinc Accumulated in the Hyperaccumulator Arabidopsis halleri1

    E-print Network

    Forms of Zinc Accumulated in the Hyperaccumulator Arabidopsis halleri1 Ge´raldine Sarret*, Pierre, MS 6­2100, Berkeley, California 94720 (M.A.M.) The chemical forms of zinc (Zn) in the Zn in their aerial parts, more than typically 10,000 g g 1 dry weight for zinc (Zn; Baker and Walker, 1990

  8. Life history traits of the pseudometallophyte Thlaspi caerulescens in natural populations from Northern Europe.

    PubMed

    Dechamps, C; Elvinger, N; Meerts, P; Lefèbvre, C; Escarré, J; Colling, G; Noret, N

    2011-01-01

    We examined recruitment, survival, life cycle and fecundity of two metallicolous (M, on metalliferous calamine soils) and two non-metallicolous (NM, on normal soils) populations of Thlaspi caerulescens in Belgium and Luxemburg. In each population, permanent plots were monitored over two reproductive seasons. In M populations, plots were located in two contrasting environments (grass versus grove) in order to test the influence of vegetation cover on life strategy. Our results show that the monocarpic life cycle is dominant in all populations of T. caerulescens. However the length of the pre-reproductive period varies from several months (winter annuals) to 1 year or more (perennials), and is partly related to plant origin (M versus NM). Most plants growing in metalliferous environments were annuals, whereas NM plants were mostly perennials. These differences in life cycle were related to differences in survival during summer, which was better in NM than in M populations. Within each M population, different survival conditions and life cycles were observed according to vegetation cover. Plants growing in grass areas were mostly annuals and had a low survival rate in summer whereas grove plants were mostly perennials and survived better in summer. Our results suggest the selection of stress avoiders (shortening of life cycle) in M populations of T. caerulescens but only for individuals growing in grass areas. Summer survival seems to play a key role in selection of life strategy in T. caerulescens. PMID:21134096

  9. www.newphytologist.org 517 Some plants hyperaccumulate selenium (Se) up to 1% of dry weight. This study

    E-print Network

    www.newphytologist.org 517 Research Summary · Some plants hyperaccumulate selenium (Se) up to 1. · Selenium hyperaccumulators Astragalus bisulcatus and Stanleya pinnata were monitored over two growing hyperaccumulation in flowers and seeds. Root Se levels were lowest in summer. Selenium concentration decreased

  10. Physiologia Plantarum 2013 2013 Scandinavian Plant Physiology Society, ISSN 0031-9317 Inoculation of selenium hyperaccumulator Stanleya pinnata

    E-print Network

    of selenium hyperaccumulator Stanleya pinnata and related non-accumulator Stanleya elata with hyperaccumulator affect elemental accumulation in hyperaccumulators (HAs). Here, two rhizosphere fungi from selenium (Se was negatively affected by AS117 and by Se, but combination of both did not reduce growth. Selenium translocation

  11. Metabolite fingerprinting of pennycress (Thlaspi arvense L.) embryos to assess active pathways during oil synthesis

    PubMed Central

    Tsogtbaatar, Enkhtuul; Cocuron, Jean-Christophe; Sonera, Marcos Corchado; Alonso, Ana Paula

    2015-01-01

    Pennycress (Thlaspi arvense L.), a plant naturalized to North America, accumulates high levels of erucic acid in its seeds, which makes it a promising biodiesel and industrial crop. The main carbon sinks in pennycress embryos were found to be proteins, fatty acids, and cell wall, which respectively represented 38.5, 33.2, and 27.0% of the biomass at 21 days after pollination. Erucic acid reached a maximum of 36% of the total fatty acids. Together these results indicate that total oil and erucic acid contents could be increased to boost the economic competitiveness of this crop. Understanding the biochemical basis of oil synthesis in pennycress embryos is therefore timely and relevant to guide future breeding and/or metabolic engineering efforts. For this purpose, a combination of metabolomics approaches was conducted to assess the active biochemical pathways during oil synthesis. First, gas chromatography–mass spectrometry (GC-MS) profiling of intracellular metabolites highlighted three main families of compounds: organic acids, amino acids, and sugars/sugar alcohols. Secondly, these intermediates were quantified in developing pennycress embryos by liquid chromatography–tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring mode. Finally, partitional clustering analysis grouped the intracellular metabolites that shared a similar pattern of accumulation over time into eight clusters. This study underlined that: (i) sucrose might be stored rather than cleaved into hexoses; (ii) glucose and glutamine would be the main sources of carbon and nitrogen, respectively; and (iii) glycolysis, the oxidative pentose phosphate pathway, the tricarboxylic acid cycle, and the Calvin cycle were active in developing pennycress embryos. PMID:25711705

  12. Metabolite fingerprinting of pennycress (Thlaspi arvense L.) embryos to assess active pathways during oil synthesis.

    PubMed

    Tsogtbaatar, Enkhtuul; Cocuron, Jean-Christophe; Sonera, Marcos Corchado; Alonso, Ana Paula

    2015-07-01

    Pennycress (Thlaspi arvense L.), a plant naturalized to North America, accumulates high levels of erucic acid in its seeds, which makes it a promising biodiesel and industrial crop. The main carbon sinks in pennycress embryos were found to be proteins, fatty acids, and cell wall, which respectively represented 38.5, 33.2, and 27.0% of the biomass at 21 days after pollination. Erucic acid reached a maximum of 36% of the total fatty acids. Together these results indicate that total oil and erucic acid contents could be increased to boost the economic competitiveness of this crop. Understanding the biochemical basis of oil synthesis in pennycress embryos is therefore timely and relevant to guide future breeding and/or metabolic engineering efforts. For this purpose, a combination of metabolomics approaches was conducted to assess the active biochemical pathways during oil synthesis. First, gas chromatography-mass spectrometry (GC-MS) profiling of intracellular metabolites highlighted three main families of compounds: organic acids, amino acids, and sugars/sugar alcohols. Secondly, these intermediates were quantified in developing pennycress embryos by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring mode. Finally, partitional clustering analysis grouped the intracellular metabolites that shared a similar pattern of accumulation over time into eight clusters. This study underlined that: (i) sucrose might be stored rather than cleaved into hexoses; (ii) glucose and glutamine would be the main sources of carbon and nitrogen, respectively; and (iii) glycolysis, the oxidative pentose phosphate pathway, the tricarboxylic acid cycle, and the Calvin cycle were active in developing pennycress embryos. PMID:25711705

  13. Selenium-tolerant diamondback moth disarms hyperaccumulator plantdefense

    SciTech Connect

    Freeman, J.L.; Quinn, C.F.; Marcus, M.A.; Fakra, S.; Pilon-Smits,E.A.H.

    2006-11-20

    Background Some plants hyperaccumulate the toxic element selenium (Se) to extreme levels, up to 1% of dry weight. The function of this intriguing phenomenon is obscure. Results Here, we show that the Se in the hyperaccumulator prince's plume (Stanleya pinnata) protects it from caterpillar herbivory because of deterrence and toxicity. In its natural habitat, however, a newly discovered variety of the invasive diamondback moth (Plutella xylostella) has disarmed this elemental defense. It thrives on plants containing highly toxic Se levels and shows no oviposition or feeding deterrence, in contrast to related varieties. Interestingly, a Se-tolerant wasp (Diadegma insulare) was found to parasitize the tolerant moth. The insect's Se tolerance mechanism was revealed by X-ray absorption spectroscopy and liquid chromatography--mass spectroscopy, which showed that the Se-tolerant moth and its parasite both accumulate methylselenocysteine, the same form found in the hyperaccumulator plant, whereas related sensitive moths accumulate selenocysteine. The latter is toxic because of its nonspecific incorporation into proteins. Indeed, the Se-tolerant diamondback moth incorporated less Se into protein. Additionally, the tolerant variety sequestered Se in distinct abdominal areas, potentially involved in detoxification and larval defense to predators. Conclusions Although Se hyperaccumulation protects plants from herbivory by some invertebrates, it can give rise to the evolution of unique Se-tolerant herbivores and thus provide a portal for Se into the local ecosystem. In a broader context, this study provides insight into the possible ecological implications of using Se-enriched crops as a source of anti-carcinogenic selenocompounds and for the remediation of Se-polluted environments.

  14. Role of trichome of Pteris vittata L. in arsenic hyperaccumulation.

    PubMed

    Li, Wenxue; Chen, Tongbin; Chen, Yang; Lei, Mei

    2005-04-01

    Environmental scanning electron microscope (ESEM) fitted with an energy dispersive X-ray microanalyzer (EDX) was used to investigate the surface micromorphology and arsenic (As) micro-distribution in Chinese brake (Pteris vittata L.). It was found that amounts of trichome, which possessed multicellular structure with the average length of 160 microm and with an average diameter of 28 microm, existed in the frond of P. vittata, and the density of trichome on the pinnate axial surface was higher than that on the petiole. Visible X-ray peak of As was recorded in the epidermal cell and trichome. The relative weight of As in the pinnate trichome, which contained the highest concentration of As among all tissues of the plant, was 2.4 and 3.9 times as much as that in the epidermal and mesophyllous cells, respectively. The As concentrations in the basal and stalk cells of the same trichome were higher than that in its cap cell. This is the first time to report that the trichome of P. vittata plays an important role in arsenic hyperaccumulation. The finding from the present study implies that much attention should be paid to the role of the trichome in understanding the hyperaccumulation and detoxicity of As in the hyperaccumulator and improving the ability of As accumulation. PMID:15986887

  15. Uptake and Cellular Compartmentalization of Metals from the Rhizosphere by Hyperaccumulating Plants: A Real Time

    E-print Network

    Sparks, Donald L.

    Uptake and Cellular Compartmentalization of Metals from the Rhizosphere by Hyperaccumulating Plants in hyperaccumulating plants. Previous attempts to establish the path of metal ingress into plant tissues have suffered-vivo response of plants to heavy metals in the rhizosphere. We first focused on characterizing the species

  16. An Arsenate-activated Glutaredoxin from the Arsenic Hyperaccumulator Fern Pteris vittata L. Regulates

    E-print Network

    Ma, Lena

    An Arsenate-activated Glutaredoxin from the Arsenic Hyperaccumulator Fern Pteris vittata L To elucidate the mechanisms of arsenic resistance in the arsenic hyperaccumulator fern Pteris vittata L., a c) reported that Chinese brake fern Pteris vittata was resistant to arsenic and was capable

  17. Absorption of foliar-applied arsenic by the arsenic hyperaccumulating fern (Pteris vittata L.)

    E-print Network

    Ma, Lena

    Absorption of foliar-applied arsenic by the arsenic hyperaccumulating fern (Pteris vittata L brake fern (Pteris vittata L.), a hyperaccumulator of arsenic, a carcinogenic metalloid, was proficient in absorbing arsenic in the form of sprays. The specific objective of this study was to investigate the impact

  18. ARSENIC UPTAKE BY TWO HYPERACCUMULATOR FERNS FROM FOUR ARSENIC CONTAMINATED SOILS

    E-print Network

    Ma, Lena

    ARSENIC UPTAKE BY TWO HYPERACCUMULATOR FERNS FROM FOUR ARSENIC CONTAMINATED SOILS A. O. FAYIGA and compare arsenic accumulation from four arsenic contaminated soils by two arsenic hyperaccumulators, Pteris for the plants, and total As, Mehlich-3 P and As, exchangeable K and Ca, and arsenic fractionation were performed

  19. Effects of selenium on arsenic uptake in arsenic hyperaccumulator Pteris vittata L. Mrittunjai Srivastava a,1

    E-print Network

    Ma, Lena

    Effects of selenium on arsenic uptake in arsenic hyperaccumulator Pteris vittata L. Mrittunjai: Hyperaccumulator Selenium Glutathione Non protein thiol TBARs a b s t r a c t Selenium (Se) is a non by Elsevier Ltd. 1. Introduction Selenium (Se) is an essential nutrient for humans and animals (Schwartz

  20. Molecular Mechanisms of Selenium Tolerance and Hyperaccumulation in Stanleya pinnata1[W][OA

    E-print Network

    Molecular Mechanisms of Selenium Tolerance and Hyperaccumulation in Stanleya pinnata1[W][OA] John L mechanisms responsible for selenium (Se) tolerance and hyperaccumulation were studied in the Se hyper of methylselenocysteine. Selenium (Se) is an essential micronutrient for many organisms, but for higher plants

  1. Molybdenum accumulation, tolerance and molybdenum-selenium-sulfur interactions in Astragalus selenium hyperaccumulator and nonaccumulator species.

    PubMed

    DeTar, Rachael Ann; Alford, Élan R; Pilon-Smits, Elizabeth A H

    2015-07-01

    Some species hyperaccumulate selenium (Se) upwards of 0.1% of dry weight. This study addressed whether Se hyperaccumulators also accumulate and tolerate more molybdenum (Mo). A field survey revealed on average 2-fold higher Mo levels in three hyperaccumulator Astragali compared to three nonaccumulator Astragali, which were not significantly different. Next, a controlled study was performed where hyperaccumulators Astragalus racemosus and Astragalus bisulcatus were compared with nonaccumulators Astragalus drummondii and Astragalus convallarius for Mo accumulation and tolerance, alone or in the presence of Se. When grown on agar media with 0, 12, 24 or 48 mg L(-1) molybdate and/or 0, 1.6 or 3.2 mg L(-1) selenate, all species decreased in biomass with increasing Mo supply. Selenium did not impact biomass at the supplied levels. All Astragali accumulated Mo upwards of 0.1% of dry weight. Selenium levels were up to 0.08% in Astragalus racemosus and 0.04% Se in the other species. Overall, there was no correlation between Se hyperaccumulation and Mo accumulation capacity. However, the hyperaccumulators and nonaccumulators differed in some respects. While none of the species had a higher tissue Mo to sulfur (S) ratio than the growth medium, nonaccumulators had a higher Mo/S ratio than hyperaccumulators. Also, while molybdate and selenate reduced S accumulation in nonaccumulators, it did not in hyperaccumulators. Furthermore, A. racemosus had a higher Se/S ratio than its medium, while the other species did not. Additionally, Mo and Se treatment affected S levels in nonaccumulators, but not in hyperaccumulators. In conclusion, there is no evidence of a link between Se and Mo accumulation and tolerance in Astragalus. Sulfate transporters in hyperaccumulating Astragali appear to have higher sulfate specificity over other oxyanions, compared to nonaccumulators, and A. racemosus may have a transporter with enhanced selenate specificity relative to sulfate or molybdate. PMID:26074355

  2. Genetic and Molecular Dissection of Arsenic Hyperaccumulation in the fern Pteris vittata.

    SciTech Connect

    Jo Ann Banks; David Salt

    2008-04-04

    Pteris vittata is a fern that is extraordinary in its ability to tolerate hyperaccumulate high levels of arsenic (As). The goals of the proposed research, to identify the genes that are necessary for As hyperaccumulation in P. vittata using molecular and genetic approaches and to understand the physiology of arsenic uptake and distribution in the living plant, were accomplished during the funding period. The genes that have been identified may ultimately enable the engineering or selection of other plants capable of As hyperaccumulation. This is important for the phytoremediation of arsenic-contaminated soils in areas where P. vittata cannot grow.

  3. Tissue fractions of cadmium in two hyperaccumulating Jerusalem artichoke genotypes.

    PubMed

    Long, Xiaohua; Ni, Ni; Liu, Zhaopu; Rengel, Zed; Jiang, Xin; Shao, Hongbo

    2014-01-01

    In order to investigate the mechanisms in two Jerusalem artichoke (Helianthus tuberosus L.) genotypes that hyperaccumulate Cd, a sand-culture experiment was carried out to characterize fractionation of Cd in tissue of Cd-hyperaccumulating genotypes NY2 and NY5. The sequential extractants were: 80% v/v ethanol (FE), deionized water (FW), 1?M NaCl (FNaCl), 2% v/v acetic acid (FAcet), and 0.6 M HCl (FHCl). After 20 days of treatments, NY5 had greater plant biomass and greater Cd accumulation in tissues than NY2. In both genotypes the FNaCl fraction was the highest in roots and stems, whereas the FAcet and FHCl fractions were the highest in leaves. With an increase in Cd concentration in the culture solution, the content of every Cd fraction also increased. The FW and FNaCl ratios in roots were lower in NY5 than in NY2, while the amount of other Cd forms was higher. It implied that, in high accumulator, namely, NY5, the complex of insoluble phosphate tends to be shaped more easily which was much better for Cd accumulation. Besides, translocation from plasma to vacuole after combination with protein may be one of the main mechanisms in Cd-accumulator Jerusalem artichoke genotypes. PMID:24883399

  4. Molecular Dissection of The Cellular Mechanisms Involved In Nickel Hyperaccumulation in Plants

    SciTech Connect

    David E. Salt

    2002-04-08

    Hyperaccumulator plant species are able to accumulate between 1-5% of their biomass as metal. However, these plants are often small, slow growing, and do not produce a high biomass. Phytoextraction, a cost-effective, in situ, plant based approach to soil remediation takes advantage of the remarkable ability of hyperaccumulating plants to concentrate metals from the soil and accumulate them in their harvestable, above-ground tissues. However, to make use of the valuable genetic resources identified in metal hyperaccumulating species, it will be necessary to transfer this material to high biomass rapidly growing crop plants. These plants would then be ideally suited to the phytoremediation process, having the ability to produce large amount of metal-rich plant biomass for rapid harvest and soil cleanup. Although progress is being made in understanding the genetic basis of metal hyperaccumulation a more complete understanding will be necessary before we can take full advantage of the genetic potential of these plants.

  5. Rhizosphere characteristics of two arsenic hyperaccumulating Pteris ferns Maria Isidria Silva Gonzaga a,b

    E-print Network

    Ma, Lena

    Rhizosphere characteristics of two arsenic hyperaccumulating Pteris ferns Maria Isidória Silva, such as fern species in the Pteris genus (Ma et al., 2001; Srivastava et al., 2006), makes phytoextraction

  6. Bacteria-Mediated Arsenic Oxidation and Reduction in the Growth Media of Arsenic Hyperaccumulator Pteris vittata

    E-print Network

    Ma, Lena

    Bacteria-Mediated Arsenic Oxidation and Reduction in the Growth Media of Arsenic Hyperaccumulator, Nanjing University, Jiangsu 210046, China ABSTRACT: Microbes play an important role in arsenic transformation and cycling in the environment. Microbial arsenic oxidation and reduction were demonstrated

  7. Characterization of arsenic-resistant bacteria from the rhizosphere of arsenic hyperaccumulator

    E-print Network

    Ma, Lena

    Characterization of arsenic-resistant bacteria from the rhizosphere of arsenic hyperaccumulator Pteris vittata Anhui Huang, Max Teplitski, Bala Rathinasabapathi, and Lena Ma Abstract: Arsenic arsenic and maintain a unique rhizosphere microbial community. Total heterotrophic counts on rich

  8. Evolutionary lineages of nickel hyperaccumulation and systematics in European Alysseae (Brassicaceae): evidence from nrDNA sequence data

    PubMed Central

    Cecchi, Lorenzo; Gabbrielli, Roberto; Arnetoli, Miluscia; Gonnelli, Cristina; Hasko, Agim; Selvi, Federico

    2010-01-01

    Background and Aims Nickel (Ni) hyperaccumulation is a rare form of physiological specialization shared by a small number of angiosperms growing on ultramafic soils. The evolutionary patterns of this feature among European members of tribe Alysseae (Brassicaceae) are investigated using a phylogenetic approach to assess relationships among Ni hyperaccumulators at the genus, species and below-species level. Methods Internal transcribed spacer (ITS) sequences were generated for multiple accessions of Alysseae. Phylogenetic trees were obtained for the genera of the tribe and Alyssum sect. Odontarrhena. All accessions and additional herbarium material were tested for Ni hyperaccumulation with the dimethylglyoxime colorimetric method. Key Results Molecular data strongly support the poorly known hyperaccumulator endemic Leptoplax (Peltaria) emarginata as sister to hyperaccumulator species of Bornmuellera within Alysseae. This is contrary to current assumptions of affinity between L. emarginata and the non-hyperaccumulator Peltaria in Thlaspideae. The lineage Bornmuellera–Leptoplax is, in turn, sister to the two non-hyperaccumulator Mediterranean endemics Ptilotrichum rupestre and P. cyclocarpum. Low ITS sequence variation was found within the monophyletic Alyssum sect. Odontarrhena and especially in A. murale sensu lato. Nickel hyperaccumulation was not monophyletic in any of three main clades retrieved, each consisting of hyperaccumulators and non-hyperaccumulators of different geographical origin. Conclusions Nickel hyperaccumulation in Alysseae has a double origin, but it did not evolve in Thlaspideae. In Bornmuellera–Leptoplax it represents an early synapomorphy inherited from an ancestor shared with the calcicolous, sister clade of Mediterranean Ptilotrichum. In Alyssum sect. Odontarrhena it has multiple origins even within the three European clades recognized. Lack of geographical cohesion suggests that accumulation ability has been lost or gained over the different serpentine areas of south Europe through independent events of microevolutionary adaptation and selection. Genetic continuity and strong phenotypic plasticity in the A. murale complex call for a reduction of the number of Ni hyperaccumulator taxa formally recognized. PMID:20724306

  9. Phylogeography of Thlaspi arvense (Brassicaceae) in China Inferred from Chloroplast and Nuclear DNA Sequences and Ecological Niche Modeling

    PubMed Central

    An, Miao; Zeng, Liyan; Zhang, Ticao; Zhong, Yang

    2015-01-01

    Thlaspi arvense is a well-known annual farmland weed with worldwide distribution, which can be found from sea level to above 4000 m high on the Qinghai-Tibetan Plateau (QTP). In this paper, a phylogeographic history of T. arvense including 19 populations from China was inferred by using three chloroplast (cp) DNA segments (trnL-trnF, rpl32-trnL and rps16) and one nuclear (n) DNA segment (Fe-regulated transporter-like protein, ZIP). A total of 11 chloroplast haplotypes and six nuclear alleles were identified, and haplotypes unique to the QTP were recognized (C4, C5, C7 and N4). On the basis of molecular dating, haplotypes C4, C5 and C7 have separated from others around 1.58 Ma for cpDNA, which corresponds to the QTP uplift. In addition, this article suggests that the T. arvense populations in China are a mixture of diverged subpopulations as inferred by hT/vT test (hT ? vT, cpDNA) and positive Tajima’s D values (1.87, 0.05 < p < 0.10 for cpDNA and 3.37, p < 0.01 for nDNA). Multimodality mismatch distribution curves and a relatively large shared area of suitable environmental conditions between the Last Glacial Maximum (LGM) as well as the present time recognized by MaxEnt software reject the sudden expansion population model. PMID:26110380

  10. Phylogeography of Thlaspi arvense (Brassicaceae) in China Inferred from Chloroplast and Nuclear DNA Sequences and Ecological Niche Modeling.

    PubMed

    An, Miao; Zeng, Liyan; Zhang, Ticao; Zhong, Yang

    2015-01-01

    Thlaspi arvense is a well-known annual farmland weed with worldwide distribution, which can be found from sea level to above 4000 m high on the Qinghai-Tibetan Plateau (QTP). In this paper, a phylogeographic history of T. arvense including 19 populations from China was inferred by using three chloroplast (cp) DNA segments (trnL-trnF, rpl32-trnL and rps16) and one nuclear (n) DNA segment (Fe-regulated transporter-like protein, ZIP). A total of 11 chloroplast haplotypes and six nuclear alleles were identified, and haplotypes unique to the QTP were recognized (C4, C5, C7 and N4). On the basis of molecular dating, haplotypes C4, C5 and C7 have separated from others around 1.58 Ma for cpDNA, which corresponds to the QTP uplift. In addition, this article suggests that the T. arvense populations in China are a mixture of diverged subpopulations as inferred by hT/vT test (hT ? vT, cpDNA) and positive Tajima's D values (1.87, 0.05 < p < 0.10 for cpDNA and 3.37, p < 0.01 for nDNA). Multimodality mismatch distribution curves and a relatively large shared area of suitable environmental conditions between the Last Glacial Maximum (LGM) as well as the present time recognized by MaxEnt software reject the sudden expansion population model. PMID:26110380

  11. A draft genome of field pennycress (Thlaspi arvense) provides tools for the domestication of a new winter biofuel crop

    PubMed Central

    Dorn, Kevin M.; Fankhauser, Johnathon D.; Wyse, Donald L.; Marks, M. David

    2015-01-01

    Field pennycress (Thlaspi arvense L.) is being domesticated as a new winter cover crop and biofuel species for the Midwestern United States that can be double-cropped between corn and soybeans. A genome sequence will enable the use of new technologies to make improvements in pennycress. To generate a draft genome, a hybrid sequencing approach was used to generate 47 Gb of DNA sequencing reads from both the Illumina and PacBio platforms. These reads were used to assemble 6,768 genomic scaffolds. The draft genome was annotated using the MAKER pipeline, which identified 27,390 predicted protein-coding genes, with almost all of these predicted peptides having significant sequence similarity to Arabidopsis proteins. A comprehensive analysis of pennycress gene homologues involved in glucosinolate biosynthesis, metabolism, and transport pathways revealed high sequence conservation compared with other Brassicaceae species, and helps validate the assembly of the pennycress gene space in this draft genome. Additional comparative genomic analyses indicate that the knowledge gained from years of basic Brassicaceae research will serve as a powerful tool for identifying gene targets whose manipulation can be predicted to result in improvements for pennycress. PMID:25632110

  12. THE EFFECT OF THE PH OF PH BUFFERED NUTRIENT SOLUTIONS ON NICKEL HYPERACCUMULATION BY ALYSSUM CORSICUM AND BERKHEYA CODDII

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is hypothesized that plant hyperaccumulation of Ni evolved as a defense mechanism against diseases and insects. Two hyperaccumulators, Alyssum corsicum and Berkheya coddii, were compared to cabbage (Brassica oleracea) grown in MES-HEPES buffered nutrient solutions and maintained at four pH levels...

  13. Soil and Water Science Department University of Florida Understanding and Enhancement of Arsenic Hyperaccumulation by a Fern Plant

    E-print Network

    Ma, Lena

    Hyperaccumulation by a Fern Plant Ma, L.Q., D. Sylvia, Y. Cai, K. Downum and J.-F. Gaillard 9/2001 to 8/2004 Arsenic discovered the only known arsenic hyperaccumulating plant, Brake fern, which accumulates >2% arsenic in its objective of this research is to understand and enhance arsenic uptake by Brake fern, with the ultimate goal

  14. Low molecular weight thiols in arsenic hyperaccumulator Pteris vittata upon exposure to arsenic and other trace elements

    E-print Network

    Ma, Lena

    Low molecular weight thiols in arsenic hyperaccumulator Pteris vittata upon exposure to arsenic; accepted 25 September 2003 ``Capsule'': Arsenic induces synthesis of low molecular weight thiols in the arsenic hyperaccumulator Pteris vittata. Abstract Low molecular weight thiol-containing compounds have

  15. Interactive effects of Cd and PAHs on contaminants removal from co-contaminated soil planted with hyperaccumulator plant Sedum alfredii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil contamination by multiple organic and inorganic contaminants is common but its remediation by hyperaccumulator plants is rarely reported. The growth of a cadmium (Cd) hyperaccumulator Sedum alfredii and removal of contaminants from Cd and polycyclic aromatic hydrocarbons(PAHs) co-contaminated s...

  16. The bacterial rhizobiome of hyperaccumulators: future perspectives based on omics analysis and advanced microscopy

    PubMed Central

    Visioli, Giovanna; D'Egidio, Sara; Sanangelantoni, Anna M.

    2015-01-01

    Hyperaccumulators are plants that can extract heavy metal ions from the soil and translocate those ions to the shoots, where they are sequestered and detoxified. Hyperaccumulation depends not only on the availability of mobilized metal ions in the soil, but also on the enhanced activity of metal transporters and metal chelators which may be provided by the plant or its associated microbes. The rhizobiome is captured by plant root exudates from the complex microbial community in the soil, and may colonize the root surface or infiltrate the root cortex. This community can increase the root surface area by inducing hairy root proliferation. It may also increase the solubility of metals in the rhizosphere and promote the uptake of soluble metals by the plant. The bacterial rhizobiome, a subset of specialized microorganisms that colonize the plant rhizosphere and endosphere, makes an important contribution to the hyperaccumulator phenotype. In this review, we discuss classic and more recent tools that are used to study the interactions between hyperaccumulators and the bacterial rhizobiome, and consider future perspectives based on the use of omics analysis and microscopy to study plant metabolism in the context of metal accumulation. Recent data suggest that metal-resistant bacteria isolated from the hyperaccumulator rhizosphere and endosphere could be useful in applications such as phytoextraction and phytoremediation, although more research is required to determine whether such properties can be transferred successfully to non-accumulator species. PMID:25709609

  17. Feasibility of using hyperaccumulating plants to bioremediate metal-contaminated soil

    SciTech Connect

    Kelly, R.J.; Guerin, T.F.

    1995-12-31

    A feasibility study was carried out to determine whether selected plants were capable of hyperaccumulating anthropogenic sources of metals found in soils from three contaminated sites. A trial was conducted using the previously reported hyperaccumulators, Armeria maritima (thrift), Impatiens balsamina (balsam), Alyssum saxatile (gold dust), and the control species, Brassica oleracea (cabbage). Although none of these plants showed any substantial hyperaccumulation of Cu, Zn, Pb, and Cd, it was established that there is an optimum period in the life-cycle of these plants in which the metal concentration reaches a maximum. This period was dependent on the metal, soil, and plant type. The current paper describes the data obtained for Zn and Cu uptake by thrift.

  18. The arsenic hyperaccumulating Pteris vittata expresses two arsenate reductases

    PubMed Central

    Cesaro, Patrizia; Cattaneo, Chiara; Bona, Elisa; Berta, Graziella; Cavaletto, Maria

    2015-01-01

    Enzymatic reduction of arsenate to arsenite is the first known step in arsenate metabolism in all organisms. Although the presence of one mRNA arsenate reductase (PvACR2) has been characterized in gametophytes of P. vittata, no arsenate reductase protein has been directly observed in this arsenic hyperaccumulating fern, yet. In order to assess the possible presence of arsenate reductase in P. vittata, two recombinant proteins, ACR2-His6 and Trx-His6-S-Pv2.5–8 were prepared in Escherichia coli, purified and used to produce polyclonal antibodies. The presence of these two enzymes was evaluated by qRT-PCR, immunoblotting and direct MS analysis. Enzymatic activity was detected in crude extracts. For the first time we detected and identified two arsenate reductase proteins (PvACR2 and Pv2.5–8) in sporophytes and gametophytes of P. vittata. Despite an increase of the mRNA levels for both proteins in roots, no difference was observed at the protein level after arsenic treatment. Overall, our data demonstrate the constitutive protein expression of PvACR2 and Pv2.5–8 in P. vittata tissues and propose their specific role in the complex metabolic network of arsenic reduction. PMID:26412036

  19. The arsenic hyperaccumulating Pteris vittata expresses two arsenate reductases.

    PubMed

    Cesaro, Patrizia; Cattaneo, Chiara; Bona, Elisa; Berta, Graziella; Cavaletto, Maria

    2015-01-01

    Enzymatic reduction of arsenate to arsenite is the first known step in arsenate metabolism in all organisms. Although the presence of one mRNA arsenate reductase (PvACR2) has been characterized in gametophytes of P. vittata, no arsenate reductase protein has been directly observed in this arsenic hyperaccumulating fern, yet. In order to assess the possible presence of arsenate reductase in P. vittata, two recombinant proteins, ACR2-His6 and Trx-His6-S-Pv2.5-8 were prepared in Escherichia coli, purified and used to produce polyclonal antibodies. The presence of these two enzymes was evaluated by qRT-PCR, immunoblotting and direct MS analysis. Enzymatic activity was detected in crude extracts. For the first time we detected and identified two arsenate reductase proteins (PvACR2 and Pv2.5-8) in sporophytes and gametophytes of P. vittata. Despite an increase of the mRNA levels for both proteins in roots, no difference was observed at the protein level after arsenic treatment. Overall, our data demonstrate the constitutive protein expression of PvACR2 and Pv2.5-8 in P. vittata tissues and propose their specific role in the complex metabolic network of arsenic reduction. PMID:26412036

  20. The arsenic hyperaccumulating Pteris vittata expresses two arsenate reductases

    NASA Astrophysics Data System (ADS)

    Cesaro, Patrizia; Cattaneo, Chiara; Bona, Elisa; Berta, Graziella; Cavaletto, Maria

    2015-09-01

    Enzymatic reduction of arsenate to arsenite is the first known step in arsenate metabolism in all organisms. Although the presence of one mRNA arsenate reductase (PvACR2) has been characterized in gametophytes of P. vittata, no arsenate reductase protein has been directly observed in this arsenic hyperaccumulating fern, yet. In order to assess the possible presence of arsenate reductase in P. vittata, two recombinant proteins, ACR2-His6 and Trx-His6-S-Pv2.5-8 were prepared in Escherichia coli, purified and used to produce polyclonal antibodies. The presence of these two enzymes was evaluated by qRT-PCR, immunoblotting and direct MS analysis. Enzymatic activity was detected in crude extracts. For the first time we detected and identified two arsenate reductase proteins (PvACR2 and Pv2.5-8) in sporophytes and gametophytes of P. vittata. Despite an increase of the mRNA levels for both proteins in roots, no difference was observed at the protein level after arsenic treatment. Overall, our data demonstrate the constitutive protein expression of PvACR2 and Pv2.5-8 in P. vittata tissues and propose their specific role in the complex metabolic network of arsenic reduction.

  1. Selenium protects the hyperaccumulator Stanleya pinnata against black-tailed prairie dog herbivory in native seleniferous habitats.

    PubMed

    Freeman, John L; Quinn, Colin F; Lindblom, Stormy Dawn; Klamper, Erin M; Pilon-Smits, Elizabeth A H

    2009-06-01

    Elemental hyperaccumulation in plants is hypothesized to represent a plant defense mechanism. The objective of this study was to determine whether selenium (Se) hyperaccumulation offers plants long-term protection from the black-tailed prairie dog (Cynomys ludovicianus). Prairie dogs are a keystone species. The hyperaccumulator Stanleya pinnata (prince's plume) co-occurs with prairie dogs in seleniferous areas in the western United States. Stanleya pinnata plants pretreated with high or low Se concentrations were planted on two prairie dog towns with different levels of herbivory pressure, and herbivory of these plants was monitored over 2 years. Throughout this study, plants with elevated Se levels suffered less herbivory and survived better than plants with low leaf Se concentrations. This study indicates that the Se in hyperaccumulator S. pinnata protects the plant in its natural habitat from herbivory by the black-tailed prairie dog. The results from this study support the hypothesis that herbivory by prairie dogs or similar small mammals has been a contributing selection pressure for the evolution of plant Se hyperaccumulation in North America. This study is the first to test the ecological significance of hyperaccumulation over a long period in a hyperaccumulator's natural habitat. PMID:21628258

  2. The role of selenium in protecting plants against prairie dog herbivory: implications for the evolution of selenium hyperaccumulation.

    PubMed

    Quinn, Colin F; Freeman, John L; Galeas, Miriam L; Klamper, Erin M; Pilon-Smits, Elizabeth A H

    2008-03-01

    Some plants can hyperaccumulate the element selenium (Se) up to 10,000 mg Se kg(-1) dry weight. Hyperaccumulation has been hypothesized to defend against herbivory. In laboratory studies high Se levels protect plants from invertebrate herbivores and pathogens. However, field studies and mammalian herbivore studies that link Se accumulation to herbivory protection are lacking. In this study a combination of field surveys and manipulative field studies were carried out to determine whether plant Se accumulation in the field deters herbivory by black-tailed prairie dogs (Cynomys ludovicianus). The Se hyperaccumulator Astragalus bisulcatus (two-grooved milkvetch) occurs naturally on seleniferous soils in the Western USA, often on prairie dog colonies. Field surveys have shown that this Se hyperaccumulator is relatively abundant on some prairie dog colonies and suffers less herbivory than other forb species. This protection was likely owing to Se accumulation, as judged from subsequent manipulative field experiments. When given a choice between pairs of plants of the Se hyperaccumulator Stanleya pinnata (prince's plume) that were pretreated with or without Se, prairie dogs preferred to feed on the plants with low Se; the same results were obtained for the non-hyperaccumulator Brassica juncea (Indian mustard). Plants containing as little as 38 mg Se kg(-1) DW were protected from herbivory. Taken together these results shed light on the functional significance of Se hyperaccumulation and the possible selection pressures driving its evolution. They also have implications for the use of plants in Se phytoremediation, or as Se-fortified crops. PMID:18278517

  3. Foliar Mn accumulation in eastern Australian herbarium specimens: prospecting for ‘new’ Mn hyperaccumulators and potential applications in taxonomy

    PubMed Central

    Fernando, Denise R.; Guymer, Gordon; Reeves, Roger D.; Woodrow, Ian E.; Baker, Alan J.; Batianoff, George N.

    2009-01-01

    Background and Aims The analysis of herbarium specimens has previously been used to prospect for ‘new’ hyperaccumulators, while the use of foliar manganese (Mn) concentrations as a taxonomic tool has been suggested. On the basis of their geographic and taxonomic affiliations to known Mn hyperaccumulators, six eastern Australian genera from the Queensland Herbarium collection were sampled for leaf tissue analyses. Methods ICP-OES was used to measure Mn and other elemental concentrations in 47 species within the genera Austromyrtus, Lenwebbia, Gossia (Myrtaceae), Macadamia (Proteaceae), Maytenus and Denhamia (Celastraceae). Key Results The resulting data demonstrated (a) up to seven ‘new’ Mn hyperaccumulators, mostly tropical rainforest species; (b) that one of these ‘new’ Mn hyperaccumulators also had notably elevated foliar Ni concentrations; (c) evidence of an interrelationship between foliar Mn and Al uptake among the Macadamias; (d) considerable variability of Mn hyperaccumulation within Gossia; and (e) the possibility that Maytenus cunninghamii may include subspecies. Conclusions Gossia bamagensis, G. fragrantissima, G. sankowsiorum, G. gonoclada and Maytenus cunninghamii were identified as ‘new’ Mn hyperaccumulators, while Gossia lucida and G. shepherdii are possible ‘new’ Mn hyperaccumulators. Of the three Myrtaceae genera examined, Mn hyperaccumulation appears restricted to Gossia, supporting its recent taxonomic revision. In the context of this present investigation and existing information, a reassesment of the general definition of Mn hyperaccumulation may be warranted. Morphological variation of Maytenus cunninghamii at two extremities was consistent with variation in Mn accumulation, indicating two possible ‘new’ subspecies. Although caution should be exercised in interpreting the data, surveying herbarium specimens by chemical analysis has provided an effective means of assessing foliar Mn accumulation. These findings should be followed up by field studies. PMID:19211572

  4. Heavy metal hyperaccumulating plants: how and why do they do it? And what makes them so interesting?

    PubMed

    Rascio, Nicoletta; Navari-Izzo, Flavia

    2011-02-01

    The term "hyperaccumulator" describes a number of plants that belong to distantly related families, but share the ability to grow on metalliferous soils and to accumulate extraordinarily high amounts of heavy metals in the aerial organs, far in excess of the levels found in the majority of species, without suffering phytotoxic effects. Three basic hallmarks distinguish hyperaccumulators from related non-hyperaccumulating taxa: a strongly enhanced rate of heavy metal uptake, a faster root-to-shoot translocation and a greater ability to detoxify and sequester heavy metals in leaves. An interesting breakthrough that has emerged from comparative physiological and molecular analyses of hyperaccumulators and related non-hyperaccumulators is that most key steps of hyperaccumulation rely on different regulation and expression of genes found in both kinds of plants. In particular, a determinant role in driving the uptake, translocation to leaves and, finally, sequestration in vacuoles or cell walls of great amounts of heavy metals, is played in hyperaccumulators by constitutive overexpression of genes encoding transmembrane transporters, such as members of ZIP, HMA, MATE, YSL and MTP families. Among the hypotheses proposed to explain the function of hyperaccumulation, most evidence has supported the "elemental defence" hypothesis, which states that plants hyperaccumulate heavy metals as a defence mechanism against natural enemies, such as herbivores. According to the more recent hypothesis of "joint effects", heavy metals can operate in concert with organic defensive compounds leading to enhanced plant defence overall. Heavy metal contaminated soils pose an increasing problem to human and animal health. Using plants that hyperaccumulate specific metals in cleanup efforts appeared over the last 20 years. Metal accumulating species can be used for phytoremediation (removal of contaminant from soils) or phytomining (growing plants to harvest the metals). In addition, as many of the metals that can be hyperaccumulated are also essential nutrients, food fortification and phytoremediation might be considered two sides of the same coin. An overview of literature discussing the phytoremediation capacity of hyperaccumulators to clean up soils contaminated with heavy metals and the possibility of using these plants in phytomining is presented. PMID:21421358

  5. Forms of Zinc Accumulated in the Hyperaccumulator Arabidopsis halleri1

    PubMed Central

    Sarret, Géraldine; Saumitou-Laprade, Pierre; Bert, Valérie; Proux, Olivier; Hazemann, Jean-Louis; Traverse, Agnès; Marcus, Matthew A.; Manceau, Alain

    2002-01-01

    The chemical forms of zinc (Zn) in the Zn-tolerant and hyperaccumulator Arabidopsis halleri and in the non-tolerant and nonaccumulator Arabidopsis lyrata subsp. petraea were determined at the molecular level by combining chemical analyses, extended x-ray absorption spectroscopy (EXAFS), synchrotron-based x-ray microfluorescence, and ?EXAFS. Plants were grown in hydroponics with various Zn concentrations, and A. halleri specimens growing naturally in a contaminated site were also collected. Zn speciation in A. halleri was independent of the origin of the plants (contaminated or non-contaminated) and Zn exposure. In aerial parts, Zn was predominantly octahedrally coordinated and complexed to malate. A secondary organic species was identified in the bases of the trichomes, which contained elevated Zn concentrations, and in which Zn was tetrahedrally coordinated and complexed to carboxyl and/or hydroxyl functional groups. This species was detected thanks to the good resolution and sensitivity of synchrotron-based x-ray microfluorescence and ?EXAFS. In the roots of A. halleri grown in hydroponics, Zn phosphate was the only species detected, and is believed to result from chemical precipitation on the root surface. In the roots of A. halleri grown on the contaminated soil, Zn was distributed in Zn malate, Zn citrate, and Zn phosphate. Zn phosphate was present in both the roots and aerial part of A. lyrata subsp. petraea. This study illustrates the complementarity of bulk and spatially resolved techniques, allowing the identification of: (a) the predominant chemical forms of the metal, and (b) the minor forms present in particular cells, both types of information being essential for a better understanding of the bioaccumulation processes. PMID:12481065

  6. Abstract Arsenic hyperaccumulator Pteris vittata L. (Chinese brake fern) grows well in arsenic-contami-

    E-print Network

    Ma, Lena

    Abstract Arsenic hyperaccumulator Pteris vittata L. (Chinese brake fern) grows well in arsenic-contami- nated media, with an extraordinary ability to tolerate high levels of arsenic. An expression cloning strategy was employed to identify cDNAs for the genes involved in arsenic resistance in P. vittata. Excised

  7. Journal of Chromatography A, 1043 (2004) 249254 Arsenic complexes in the arsenic hyperaccumulator

    E-print Network

    Ma, Lena

    2004-01-01

    Journal of Chromatography A, 1043 (2004) 249­254 Arsenic complexes in the arsenic hyperaccumulator-exchange chromatography­hydride generation­atomic fluorescence spectroscopy and size-exclusion chromatographyIII-tris-thiolate complexes through thiolate bonds by us- ing size-exclusion chromatography (SEC) or electrospray ionization

  8. Thiol synthesis and arsenic hyperaccumulation in Pteris vittata (Chinese brake fern)

    E-print Network

    Ma, Lena

    Thiol synthesis and arsenic hyperaccumulation in Pteris vittata (Chinese brake fern) Weihua Zhanga in arsenic detoxification. Abstract Pteris vittata (Chinese brake fern) has potential for phytoremediation to be a supplement. Ó 2004 Elsevier Ltd. All rights reserved. Keywords: Pteris vittata; Chinese brake fern; Thiols

  9. Using phosphate rock to immobilize metals in soil and increase arsenic uptake by hyperaccumulator Pteris vittata

    E-print Network

    Ma, Lena

    Using phosphate rock to immobilize metals in soil and increase arsenic uptake by hyperaccumulator 2005 Abstract This greenhouse experiment evaluated the effects of phosphate rock (PR) on arsenic mg kgÀ1 . Phosphate rock also significantly reduced Pb (13.5 to 4.10 mg kgÀ 1 ) and Cd (13.0 to 3

  10. Arsenic transformation in the growth media and biomass of hyperaccumulator Pteris vittata L.

    E-print Network

    Ma, Lena

    Arsenic transformation in the growth media and biomass of hyperaccumulator Pteris vittata L. Shiny online 20 June 2010 Keywords: Pteris vittata Arsenic Speciation Reduction Oxidation a b s t r a c.10­0.27 mM AsV or AsIII solution under aerated or sterile condition for 1 h to 14 d. Arsenic speciation

  11. Phytoextraction by arsenic hyperaccumulator Pteris vittata L. from six arsenic-contaminated soils: Repeated harvests

    E-print Network

    Ma, Lena

    Phytoextraction by arsenic hyperaccumulator Pteris vittata L. from six arsenic-contaminated soils: Repeated harvests and arsenic redistribution Maria I.S. Gonzaga a , Jorge A.G. Santos a , Lena Q. Ma b was effective in continuously removing arsenic from contaminated soils after three repeated harvests. Abstract

  12. Hyperaccumulator Alyssum Murale Relies on a Different Metal Storage Mechanism for Cobalt than for Nickel.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nickel hyperaccumulator Alyssum murale has been developed as a commercial crop for phytoremediation/phytomining Ni-enriched soils (anthropogenic/geogenic) containing elevated concentrations of other metals. Metal co-tolerance, accumulation, and localization were investigated for Alyssum exposed to c...

  13. Selenium Hyperaccumulator Plants Stanleya pinnata and Astragalus bisulcatus Are Colonized by Se-Resistant, Se-

    E-print Network

    -Resistant, Se- Excluding Wasp and Beetle Seed Herbivores John L. Freeman1,2 *, Matthew A. Marcus3 , Sirine C Biology Department, Colorado State University, Fort Collins, Colorado, United States of America Abstract was investigated in seed chalcids and seed beetles found consuming seeds inside pods of Se-hyperaccumulator species

  14. The Metal Hyperaccumulator Alyssum murale Uses Nitrogen and Oxygen Donor Ligands for Ni Transport and Storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Kotodesh genotype of the nickel (Ni) hyperaccumulator Alyssum murale was examined to determine the compartmentalization and internal speciation of Ni, and other elements, in an effort to ascertain the mechanism used by this plant to tolerate extremely high shoot Ni concentrations. Plants were g...

  15. The leguminous species Anthyllis vulneraria as a Zn-hyperaccumulator and eco-Zn catalyst resources.

    PubMed

    Grison, Claire M; Mazel, Marine; Sellini, Amandine; Escande, Vincent; Biton, Jacques; Grison, Claude

    2015-04-01

    Anthyllis vulneraria was highlighted here as a Zn-hyperaccumulator for the development of a pilot phytoextraction process in the mine site of Les Avinières in the district of Saint-Laurent-Le-Minier. A. vulneraria appeared to hyperaccumulate the highest concentration of Zn in shoots with a better metal selectivity relative to Cd and Pb than the reference Zn-hyperaccumulator Noccea caerulescens. A bigger biomass production associated to a higher Zn concentration conducted A. vulneraria to the highest total zinc gain per hectare per year. As a legume, A. vulneraria was infected by rhizobia symbionts. Inoculation of A. vulneraria seeds showed a positive impact on Zn hyperaccumulation. A large-scale culture process of symbiotic rhizobia of A. vulneraria was investigated and optimized to allow large-scale inoculation process. Contaminated shoots of A. vulneraria were not considered as wastes and were recovered as Eco-Zn catalyst in particular, examples of organic synthesis, electrophilic aromatic substitution. Eco-Zn catalyst was much more efficient than conventional catalysts and allowed greener chemical processes. PMID:25253057

  16. THE PLANT SOIL INTERFACE: NICKEL BIOAVAILABILITY AND THE MECHANISMS OF PLANT HYPERACCUMULATION

    E-print Network

    Sparks, Donald L.

    THE PLANT SOIL INTERFACE: NICKEL BIOAVAILABILITY AND THE MECHANISMS OF PLANT HYPERACCUMULATION fulfillment of the requirements for the degree of Doctor of Philosophy in Plant and Soil Sciences Winter 2006 and Learning Company. #12;ii THE PLANT SOIL INTERFACE: NICKEL BIOAVAILABILITY AND THE MECHANISMS OF PLANT

  17. Nickel hyperaccumulation as an elemental defense of Streptanthus polygaloides (Brassicaceae): influence of herbivore feeding mode.

    PubMed

    Jhee, Edward M; Boyd, Robert S; Eubanks, Micky D

    2005-11-01

    No study of a single nickel (Ni) hyperaccumulator species has investigated the impact of hyperaccumulation on herbivores representing a variety of feeding modes. Streptanthus polygaloides plants were grown on high- or low-Ni soils and a series of no-choice and choice feeding experiments was conducted using eight arthropod herbivores. Herbivores used were two leaf-chewing folivores (the grasshopper Melanoplus femurrubrum and the lepidopteran Evergestis rimosalis), a dipteran rhizovore (the cabbage maggot Delia radicum), a xylem-feeder (the spittlebug Philaenus spumarius), two phloem-feeders (the aphid, Lipaphis erysimi and the spidermite Trialeurodes vaporariorum) and two cell-disruptors (the bug Lygus lineolaris and the whitefly Tetranychus urticae). Hyperaccumulated Ni significantly decreased survival of the leaf-chewers and rhizovore, and significantly reduced population growth of the whitefly cell-disruptor. However, vascular tissue-feeding insects were unaffected by hyperaccumulated Ni, as was the bug cell-disruptor. We conclude that Ni can defend against tissue-chewing herbivores but is ineffective against vascular tissue-feeding herbivores. The effects of Ni on cell-disruptors varies, as a result of either variation of insect Ni sensitivity or the location of Ni in S. polygaloides cells and tissues. PMID:16219073

  18. American Journal of Botany 89(6): 9981003. 2002. THE DEFENSIVE ROLE OF NI HYPERACCUMULATION BY

    E-print Network

    Boyd, Robert S.

    experimental design. Streptanthus polygaloides plants were grown in a greenhouse for 2 mo, transplanted- tolerant plant species, termed ``hyperaccumulators'' by Brooks et al. (1977), have remarkably elevated is a metal tolerance mechanism (Antonovics, Bradshaw, and Turner, 1971; Baker, 1981, 1987; Kruckeberg

  19. Do selenium hyperaccumulators affect selenium speciation in neighboring plants and soil? An X-Ray Microprobe Analysis.

    PubMed

    El Mehdawi, Ali F; Lindblom, Stormy D; Cappa, Jennifer J; Fakra, Sirine C; Pilon-Smits, Elizabeth A H

    2015-01-01

    Neighbors of Se hyperaccumulators Stanleya pinnata and Astragalus bisulcatus were found earlier to have elevated Se levels. Here we investigate whether Se hyperaccumulators affect Se localization and speciation in surrounding soil and neighboring plants. X-ray fluorescence mapping and X-ray absorption near-edge structure spectroscopy were used to analyze Se localization and speciation in leaves of Artemisia ludoviciana, Symphyotrichum ericoides and Chenopodium album growing next to Se hyperaccumulators or non-accumulators at a seleniferous site. Regardless of neighbors, A. ludoviciana, S. ericoides and C. album accumulated predominantly (73-92%) reduced selenocompounds with XANES spectra similar to the C-Se-C compounds selenomethionine and methyl-selenocysteine. Preliminary data indicate that the largest Se fraction (65-75%), both in soil next to hyperaccumulator S. pinnata and next to nonaccumulator species was reduced Se with spectra similar to C-Se-C standards. These same C-Se-C forms are found in hyperaccumulators. Thus, hyperaccumulator litter may be a source of organic soil Se, but soil microorganisms may also contribute. These findings are relevant for phytoremediation and biofortification since organic Se is more readily accumulated by plants, and more effective for dietary Se supplementation. PMID:26030363

  20. Selection and combustion of Ni-hyperaccumulators for the phytomining process.

    PubMed

    Zhang, Xin; Houzelot, Vivian; Bani, Aida; Morel, Jean Louis; Echevarria, Guillaume; Simonnot, Marie-Odile

    2014-01-01

    Ni recovery from serpentine soils by phytomining has proved feasible. Phytomining involves the crop of hyperaccumulating plants with high Ni contents and the valorization of Ni by pyro or hydrometallurgical process. In order to evaluate the Ni content of different plants, we analyzed the organs of 14 hyperaccumulators from three genera: Alyssum, Leptoplax and Bornmuellera. The highest concentration was recorded in the leaves of Leptoplax (34.3 +/- 0.7 mg g(-1)DM). Additionally, we investigated biomass combustion which is the first step of the process we designed to obtain a nickel salt. We showed that temperature and duration were important parameters to ensure a good quality of ashes. At the bench scale, the best conditions were 550 degrees C and 3 h. In this way, we obtained ashes in which Ni could reach 20 wt%. Biomass ashes can be considered as a bio-ore for recovering metal value. PMID:24933902

  1. Thermal Characteristics of Hyperaccumulator and Fate of Heavy Metals during Thermal Treatment of Sedum plumbizincicola.

    PubMed

    Zhong, Daoxu; Zhong, Zhaoping; Wu, Longhua; Xue, Hui; Song, Zuwei; Luo, Yongming

    2015-01-01

    Thermal treatment is one of the most promising disposal techniques for heavy metal- (HM)-enriched hyperaccumulators. However, the thermal characteristics and fate of HMs during thermal treatment of hyperaccumulator biomass need to be known in detail. A horizontal tube furnace was used to analyze the disposal process of hyperaccumulator biomass derived from a phyto-extracted field in which the soil was moderately contaminated with heavy metals. Different operational conditions regarding temperature and gas composition were tested. A thermo-dynamic analysis by advanced system for process engineering was performed to predict HM speciation during thermal disposal and SEM-EDS, XRD and sequential chemical extraction were used to characterize the heavy metals. The recovery of Zn, Pb and Cd in bottom ash decreased with increasing temperature but recovery increased in the fly ash. Recovery of Zn, Pb and Cd fluctuated with increasing air flow rate and the metal recovery rates were higher in the fly ash than the bottom ash. Most Cl, S, Fe, Al and SiO2 were found as alkali oxides, SO2, Fe2(SO4)3, iron oxide, Ca3Al2O6, K2SiO3 and SiO2 instead of reacting with HMs. Thus, the HMs were found to occur as the pure metals and their oxides during the combustion process and as the sulfides during the reducing process. PMID:26030364

  2. A more complete picture of metal hyperaccumulation through next-generation sequencing technologies

    PubMed Central

    Verbruggen, Nathalie; Hanikenne, Marc; Clemens, Stephan

    2013-01-01

    The mechanistic understanding of metal hyperaccumulation has benefitted immensely from the use of molecular genetics tools developed for Arabidopsis thaliana. The revolution in DNA sequencing will enable even greater strides in the near future, this time not restricted to the family Brassicaceae. Reference genomes are within reach for many ecologically interesting species including heterozygous outbreeders. They will allow deep RNA-seq transcriptome studies and the re-sequencing of contrasting individuals to unravel the genetic basis of phenotypic variation. Cell-type specific transcriptome analyses, which will be essential for the dissection of metal translocation pathways in hyperaccumulators, can be achieved through the combination of RNA-seq and translatome approaches. Affordable high-resolution genotyping of many individuals enables the elucidation of quantitative trait loci in intra- and interspecific crosses as well as through genome-wide association mapping across large panels of accessions. Furthermore, genome-wide scans have the power to detect loci under recent selection. Together these approaches will lead to a detailed understanding of the evolutionary path towards the emergence of hyperaccumulation traits. PMID:24098304

  3. Mn accumulation and tolerance in Celosia argentea Linn.: a new Mn-hyperaccumulating plant species.

    PubMed

    Liu, Jie; Shang, Weiwei; Zhang, Xuehong; Zhu, Yinian; Yu, Ke

    2014-02-28

    Identifying a hyperaccumulator is an important groundwork for the phytoextraction of heavy metal-contaminated soil. Celosia argentea Linn., which grew on a Mn tailing wasteland, was found to hyperaccumulate Mn (14 362mgkg(-1) in leaf dry matter) in this study. To investigate Mn tolerance and accumulation in C. argentea, a hydroponic culture experiment was conducted in a greenhouse. Results showed that the biomass and the relative growth rate of C. argentea were insignificantly different (p>0.05) at the Mn supply level ranging from 2.5mgL(-1) (control) to 400mgL(-1). Manganese concentrations in leaves, stems, and roots reached maxima of 20228, 8872, and 2823mgkg(-1) at 600mgMnL(-1), respectively. The relative rate of Mn accumulation increased by 91.2% at 400mgMnL(-1). Over 95% of the total Mn taken up by C. argentea was translocated to shoots. Thus, C. argentea exhibits the basic characteristics of a Mn-hyperaccumulator. This species has great potential to remediate Mn-contaminated soil cheaply and can also aid the studies of Mn uptake, translocation, speciation, distribution and detoxification in plants. PMID:24444455

  4. Geogenic Nickel Speciation in Serpentine Soils and Its Relationship to Nickel Uptake in Hyperaccumulator Plants. Tuesday, November 3, 2009: 3:00 PM

    E-print Network

    Sparks, Donald L.

    in Hyperaccumulator Plants. Tuesday, November 3, 2009: 3:00 PM Convention Center, Room 334, Third Floor Matthew Siebecker1, Tiziana Centofanti2, Rufus Chaney2 and Donald Sparks1, (1)Plant and Soil Sciences, Univ. of Delaware, Newark, DE (2)USDA-ARS, Beltsville, MD Hyperaccumulating plants have an extraordinary ability

  5. Interactive effects of pH, arsenic and phosphorus on uptake of As and P and growth of the arsenic hyperaccumulator Pteris

    E-print Network

    Ma, Lena

    hyperaccumulator Pteris vittata L. under hydroponic conditions S. Tu, L.Q. Ma * Soil and Water Science Department, especially water. Two sets of hydroponic experiments were conducted using three-factor, five-level central design; Hydroponics; Hyperaccumulation; Pteris vittata L. 1. Introduction In recent years, arsenic (As

  6. Selenium hyperaccumulators harbor a diverse endophytic bacterial community characterized by high selenium resistance and plant growth promoting properties.

    PubMed

    Sura-de Jong, Martina; Reynolds, Ray J B; Richterova, Klara; Musilova, Lucie; Staicu, Lucian C; Chocholata, Iva; Cappa, Jennifer J; Taghavi, Safiyh; van der Lelie, Daniel; Frantik, Tomas; Dolinova, Iva; Strejcek, Michal; Cochran, Alyssa T; Lovecka, Petra; Pilon-Smits, Elizabeth A H

    2015-01-01

    Selenium (Se)-rich plants may be used to provide dietary Se to humans and livestock, and also to clean up Se-polluted soils or waters. This study focused on endophytic bacteria of plants that hyperaccumulate selenium (Se) to 0.5-1% of dry weight. Terminal restriction fragment length polymorphism (T-RFLP) analysis was used to compare the diversity of endophytic bacteria of hyperaccumulators Stanleya pinnata (Brassicaceae) and Astragalus bisulcatus (Fabaceae) with those from related non-accumulators Physaria bellii (Brassicaceae) and Medicago sativa (Fabaceae) collected on the same, seleniferous site. Hyperaccumulators and non-accumulators showed equal T-RF diversity. Parsimony analysis showed that T-RFs from individuals of the same species were more similar to each other than to those from other species, regardless of plant Se content or spatial proximity. Cultivable endophytes from hyperaccumulators S. pinnata and A. bisulcatus were further identified and characterized. The 66 bacterial morphotypes were shown by MS MALDI-TOF Biotyper analysis and 16S rRNA gene sequencing to include strains of Bacillus, Pseudomonas, Pantoea, Staphylococcus, Paenibacillus, Advenella, Arthrobacter, and Variovorax. Most isolates were highly resistant to selenate and selenite (up to 200 mM) and all could reduce selenite to red elemental Se, reduce nitrite and produce siderophores. Seven isolates were selected for plant inoculation and found to have plant growth promoting properties, both in pure culture and when co-cultivated with crop species Brassica juncea (Brassicaceae) or M. sativa. There were no effects on plant Se accumulation. We conclude that Se hyperaccumulators harbor an endophytic bacterial community in their natural seleniferous habitat that is equally diverse to that of comparable non-accumulators. The hyperaccumulator endophytes are characterized by high Se resistance, capacity to produce elemental Se and plant growth promoting properties. PMID:25784919

  7. Selenium hyperaccumulators harbor a diverse endophytic bacterial community characterized by high selenium resistance and plant growth promoting properties

    PubMed Central

    Sura-de Jong, Martina; Reynolds, Ray J. B.; Richterova, Klara; Musilova, Lucie; Staicu, Lucian C.; Chocholata, Iva; Cappa, Jennifer J.; Taghavi, Safiyh; van der Lelie, Daniel; Frantik, Tomas; Dolinova, Iva; Strejcek, Michal; Cochran, Alyssa T.; Lovecka, Petra; Pilon-Smits, Elizabeth A. H.

    2015-01-01

    Selenium (Se)-rich plants may be used to provide dietary Se to humans and livestock, and also to clean up Se-polluted soils or waters. This study focused on endophytic bacteria of plants that hyperaccumulate selenium (Se) to 0.5–1% of dry weight. Terminal restriction fragment length polymorphism (T-RFLP) analysis was used to compare the diversity of endophytic bacteria of hyperaccumulators Stanleya pinnata (Brassicaceae) and Astragalus bisulcatus (Fabaceae) with those from related non-accumulators Physaria bellii (Brassicaceae) and Medicago sativa (Fabaceae) collected on the same, seleniferous site. Hyperaccumulators and non-accumulators showed equal T-RF diversity. Parsimony analysis showed that T-RFs from individuals of the same species were more similar to each other than to those from other species, regardless of plant Se content or spatial proximity. Cultivable endophytes from hyperaccumulators S. pinnata and A. bisulcatus were further identified and characterized. The 66 bacterial morphotypes were shown by MS MALDI-TOF Biotyper analysis and 16S rRNA gene sequencing to include strains of Bacillus, Pseudomonas, Pantoea, Staphylococcus, Paenibacillus, Advenella, Arthrobacter, and Variovorax. Most isolates were highly resistant to selenate and selenite (up to 200 mM) and all could reduce selenite to red elemental Se, reduce nitrite and produce siderophores. Seven isolates were selected for plant inoculation and found to have plant growth promoting properties, both in pure culture and when co-cultivated with crop species Brassica juncea (Brassicaceae) or M. sativa. There were no effects on plant Se accumulation. We conclude that Se hyperaccumulators harbor an endophytic bacterial community in their natural seleniferous habitat that is equally diverse to that of comparable non-accumulators. The hyperaccumulator endophytes are characterized by high Se resistance, capacity to produce elemental Se and plant growth promoting properties. PMID:25784919

  8. Extraction and isolation of the salidroside-type metabolite from zinc (Zn) and cadmium (Cd) hyperaccumulator Sedum alfredii Hance*

    PubMed Central

    Xing, Yan; Peng, Hong-yun; Li, Xia; Zhang, Meng-xi; Gao, Ling-ling; Yang, Xiao-e

    2012-01-01

    The active metabolite in the post-harvested biomass of zinc (Zn) and cadmium (Cd) hyperaccumulator Sedum alfredii Hance from phytoextraction is of great interest in China. The current study demonstrates that a salidroside-type metabolite can be yielded from the Zn/Cd hyperaccumulator S. alfredii biomass by means of sonication/ethanol extraction and macroporous resin column (AB-8 type) isolation. The concentrations of Zn and Cd in the salidroside-type metabolite were below the limitation of the national standards. PMID:23024051

  9. De novo assembly of the pennycress (Thlaspi arvense) transcriptome provides tools for the development of a winter cover crop and biodiesel feedstock

    PubMed Central

    Dorn, Kevin M; Fankhauser, Johnathon D; Wyse, Donald L; Marks, M David

    2013-01-01

    Field pennycress (Thlaspi arvense L.) has potential as an oilseed crop that may be grown during fall (autumn) and winter months in the Midwestern United States and harvested in the early spring as a biodiesel feedstock. There has been little agronomic improvement in pennycress through traditional breeding. Recent advances in genomic technologies allow for the development of genomic tools to enable rapid improvements to be made through genomic assisted breeding. Here we report an annotated transcriptome assembly for pennycress. RNA was isolated from representative plant tissues, and 203 million unique Illumina RNA-seq reads were produced and used in the transcriptome assembly. The draft transcriptome assembly consists of 33 873 contigs with a mean length of 1242 bp. A global comparison of homology between the pennycress and Arabidopsis transcriptomes, along with four other Brassicaceae species, revealed a high level of global sequence conservation within the family. The final assembly was functionally annotated, allowing for the identification of putative genes controlling important agronomic traits such as flowering and glucosinolate metabolism. Identification of these genes leads to testable hypotheses concerning their conserved function and to rational strategies to improve agronomic properties in pennycress. Future work to characterize isoform variation between diverse pennycress lines and develop a draft genome sequence for pennycress will further direct trait improvement. PMID:23786378

  10. A comparative analysis of endophytic bacterial communities associated with hyperaccumulators growing in mine soils.

    PubMed

    Chen, Liang; Luo, Shenglian; Chen, Jueliang; Wan, Yong; Li, Xiaojie; Liu, Chengbin; Liu, Feng

    2014-06-01

    Interactions between endophytic bacterial communities and hyperaccumulators in heavy metal-polluted sites are not fully understood. In this study, the diversity of stem-associated endophytic bacterial communities of two hyperaccumulators (Solanum nigrum L. and Phytolacca acinosa Roxb.) growing in mine soils was investigated using molecular-based methods. The denaturing gradient gel electrophoresis (DGGE) analysis showed that the endophytic bacterial community structures were affected by both the level of heavy metal pollution and the plant species. Heavy metal in contaminated soil determined, to a large extent, the composition of the different endophytic bacterial communities in S. nigrum growing across soil series (five sampling spots, and the concentration of Cd is from 0.2 to 35.5 mg/kg). Detailed analysis of endophytic bacterial populations by cloning of 16S rRNA genes amplified from the stems of the two plants at the same site revealed a different composition. A total of 51 taxa at the genus level that included ?-, ?-, and ?-Proteobacteria (68.8% of the two libraries clones), Bacteroidetes (9.0% of the two libraries clones), Firmicutes (2.0% of the two libraries clones), Actinobacteria (16.4% of the two libraries clones), and unclassified bacteria (3.8% of the two libraries clones) were found in the two clone libraries. The most abundant genus in S. nigrum was Sphingomonas (23.35%), while Pseudomonas prevailed in P. acinosa (21.40%). These results suggest that both heavy metal pollution and plant species contribute to the shaping of the dynamic endophytic bacterial communities associated with stems of hyperaccumulators. PMID:24595752

  11. Effects of arsenate, chromate, and sulfate on arsenic and chromium uptake and translocation by arsenic hyperaccumulator Pteris vittata L.

    E-print Network

    Ma, Lena

    Effects of arsenate, chromate, and sulfate on arsenic and chromium uptake and translocation 18 July 2013 Accepted 16 August 2013 Keywords: Phytoremediation Hyperaccumulator Arsenic Chromium and translocation by PV. Published by Elsevier Ltd. 1. Introduction Arsenic (As) and chromium (Cr) are both

  12. REALISATION OF THE POTENTIAL FOR USING HYPERACCUMULATING MTP'S IN THE REMEDIATION OF CONTAMINATED LAND AT MINES AND ELSEWHERE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper considers our state of knowledge of metal-tolerant plants (MTPs) as they occur in nature, and the discovery of the behaviour of those species that act as hyperaccumulators. Plant species highly resistant to soil metals have evolved at many locations where surface soils were rich in metals...

  13. Nickel and Manganese Accumulation, Interaction and Localization in Leaves of the Ni Hyperaccumulators Alyssum murale and Alyssum corsicum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genus Alyssum contains >50 Ni hyperaccumulator species; many can achieve 3% Ni in dry leaf. In soils with normal Mn levels, Alyssum trichome bases were observed previously to accumulate Ni and Mn to high levels. Here we report concentration and localization patterns in A. murale and A. corsicum...

  14. Do High-nickel Leaves Shed by the Ni-hyperaccumulator Alyssum Murale Inhibit Seed Germination of Competing Plants?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elemental allelopathy suggests that nickel (Ni)-rich leaves shed by hyperaccumulators inhibit the germination and growth of nearby plant species. Here, the germination of eight herbaceous species following addition of Alyssum murale biomass or Ni(NO3)2, with the same Ni level added to soil, was ass...

  15. HOST-SWITCHING DOES NOT CIRCUMVENT THE NI-BASED DEFENCE OF THE NI HYPERACCUMULATOR STREPTANTHUS POLYGALOIDES (BRASSICACEAE)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foliar concentration of heavy metals, such as nickel, may help defend metal --hyperaccumulating plants against both herbivores and pathogens. Host switching by generalist herbivores might be one strategy by which they can dilute lifetime consumption of toxic nickel. We examined the effects of host...

  16. Exogenous cytokinin treatments of a Ni hyper-accumulator, Alyssum murale, grown in a serpentine soil: Implications for phytoextraction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Application of exogenous plant growth regulators was examined as a viable technique to increase the efficiency of plant metal phytoextraction from contaminated soils. The aim of this study was to investigate the alteration of Ni phytoextraction by Alyssum murale, a Ni hyperaccumulator, following the...

  17. Potential hyperaccumulation of Pb, Zn, Cu and Cd in endurant plants distributed in an old smeltery, northeast China

    NASA Astrophysics Data System (ADS)

    Cui, Shuang; Zhou, Qixing; Chao, Lei

    2007-01-01

    The absorption and accumulation of Pb, Zn, Cu and Cd in some endurant weed plant species that survived in an old smeltery in Liaoning, China, were systematically investigated. Potential hyperaccumulative characteristics of these species were also discussed. The results showed that metal accumulation in plants differed with species, tissues and metals. Endurant weed plants growing in this contaminated site exhibited high metal adaptability. Both the metal exclusion and detoxification tolerance strategies were involved in the species studied. Seven species for Pb and four species for Cd were satisfied for the concentration time level standard for hyperaccumulator. Considering translocation factor (TF) values, one species for Pb, seven species for Zn, two species for Cu and five species for Cd possessed the characteristic of hyperaccumulator. Particularly, Abutilon theophrasti Medic, exhibited strong accumulative ability to four heavy metals. Although enrichment coefficients of all samples were lesser than 1 and the absolute concentrations didn’t reach the standard, species mentioned above were primarily believed to be potential hyperaccumulators.

  18. Selenium biofortification of broccoli and carrots grown in soil amended with Se-enriched hyperaccumulator Stanleya pinnata

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Amending soils with Se-hyperaccumulator plant derived sources of selenium (Se) may be useful for increasing Se content in food crops in Se-deficient regions of the world. In this study, we evaluated total Se and the different chemical species of Se in broccoli and carrots grown in soils amended with...

  19. ESEM-EDS: In vivo characterization of the Ni hyperaccumulator Noccaea caerulescens.

    PubMed

    Mattarozzi, Monica; Visioli, Giovanna; Sanangelantoni, Anna Maria; Careri, Maria

    2015-08-01

    Environmental scanning electron microscopy (ESEM) permits to analyze samples in their native-hydrated state, allowing a broad spectrum of biological applications. In this study, ESEM equipped with energy dispersive X-ray spectrometer (EDS) was used as a fast method to analyze tissue morphology and to investigate metal distribution in the Ni hyperaccumulator Noccaea caerulescens, an established model to study the adaptation of plants to metalliferous soils. The low vacuum and wet mode operative conditions required the proper choice of experimental parameters both for morphological and compositional characterization of plant tissues. The calibration strategy for semi-quantitative analysis involved the use of Ni fortified agar as standard and signal normalization respect to endogenous carbon, chosen as internal standard. The obtained results are in accordance with present literature, showing a preferential Ni distribution in the epidermal cells respect to near the stomata for leaves and in the cotyledon epidermidis respect to cotyledon parenchyma area for seeds. Thanks to the absence of any time consuming sample treatment steps, ESEM-EDS technique can be proposed as valid strategy for in vivo high-throughput analysis of plant tissues and for a rapid screening and identification of other hyperaccumulator plants in a selected contaminated area. PMID:25984895

  20. Combined endophytic inoculants enhance nickel phytoextraction from serpentine soil in the hyperaccumulator Noccaea caerulescens.

    PubMed

    Visioli, Giovanna; Vamerali, Teofilo; Mattarozzi, Monica; Dramis, Lucia; Sanangelantoni, Anna M

    2015-01-01

    This study assesses the effects of specific bacterial endophytes on the phytoextraction capacity of the Ni-hyperaccumulator Noccaea caerulescens, spontaneously growing in a serpentine soil environment. Five metal-tolerant endophytes had already been selected for their high Ni tolerance (6 mM) and plant growth promoting ability. Here we demonstrate that individual bacterial inoculation is ineffective in enhancing Ni translocation and growth of N. caerulescens in serpentine soil, except for specific strains Ncr-1 and Ncr-8, belonging to the Arthrobacter and Microbacterium genera, which showed the highest indole acetic acid production and 1-aminocyclopropane-1-carboxylic acid-deaminase activity. Ncr-1 and Ncr-8 co-inoculation was even more efficient in promoting plant growth, soil Ni removal, and translocation of Ni, together with that of Fe, Co, and Cu. Bacteria of both strains densely colonized the root surfaces and intercellular spaces of leaf epidermal tissue. These two bacterial strains also turned out to stimulate root length, shoot biomass, and Ni uptake in Arabidopsis thaliana grown in MS agar medium supplemented with Ni. It is concluded that adaptation of N. caerulescens in highly Ni-contaminated serpentine soil can be enhanced by an integrated community of bacterial endophytes rather than by single strains; of the former, Arthrobacter and Microbacterium may be useful candidates for future phytoremediation trials in multiple metal-contaminated sites, with possible extension to non-hyperaccumulator plants. PMID:26322074

  1. Cellular Sequestration of Cadmium in the Hyperaccumulator Plant Species Sedum alfredii

    SciTech Connect

    Tian, Shengke; Lu, Lingli; Labavitch, John M.; Yang, Xiaoe; He, Zhenli; Hu, Hening; Sarangi, Ritimukta; Newville, Matt; Commisso, Joel; Brown, Patrick Hugh

    2012-07-23

    Spatial imaging of cadmium (Cd) in the hyperaccumulator Sedum alfredii was investigated in vivo by laser ablation inductively coupled plasma mass spectrometry and x-ray microfluorescence imaging. Preferential Cd accumulation in the pith and cortex was observed in stems of the Cd hyperaccumulating ecotype (HE), whereas Cd was restricted to the vascular bundles in its contrasting nonhyperaccumulating ecotype. Cd concentrations of up to 15,000 {micro}g g{sup -1} were measured in the pith cells, which was many fold higher than the concentrations in the stem epidermis and vascular bundles in the HE plants. In the leaves of the HE, Cd was mainly localized to the mesophyll and vascular cells rather than the epidermis. The distribution pattern of Cd in both stems and leaves of the HE was very similar to calcium but not zinc, irrespective of Cd exposure levels. Extended x-ray absorption fine structure spectroscopy analysis showed that Cd in the stems and leaves of the HE was mainly associated with oxygen ligands, and a larger proportion (about 70% in leaves and 47% in stems) of Cd was bound with malic acid, which was the major organic acid in the shoots of the plants. These results indicate that a majority of Cd in HE accumulates in the parenchyma cells, especially in stems, and is likely associated with calcium pathways and bound with organic acid (malate), which is indicative of a critical role of vacuolar sequestration of Cd in the HE S. alfredii.

  2. Rhizosphere characteristics of zinc hyperaccumulator Sedum alfredii involved in zinc accumulation.

    PubMed

    Li, Tingqiang; Di, Zhenzhen; Islam, Ejazul; Jiang, Hong; Yang, Xiaoe

    2011-01-30

    A hyperaccumulating ecotype (HE) and a non-hyperaccumulating ecotype (NHE) of Sedum alfredii were grown in a pot experiment to investigate the chemical characteristics of the rhizosphere. The results indicated that HE accumulated more Zn in the shoot than NHE after growing in both heavily and slightly polluted soil. The water soluble Zn and mobile Zn (extractable with 1M NH(4)NO(3)) fraction in both rhizosphere and bulk soils decreased considerably after growth of HE compared to NHE. However, the decreases in mobile fraction accounted for less than 8.5% of the total Zn uptake by HE indicating that HE was effective in mobilizing Zn from the non-mobile fractions. Zinc-induced root exudates reduced the soil pH (by 0.6-0.8 units) and increased dissolved organic carbon concentrations in the rhizosphere of HE compared to the bulk soil. The dissolved organic matter (DOM) from the rhizosphere of HE showed greater (1.7-2.5 times) extracting ability of Zn from various Zn minerals than those of NHE-DOM (P<0.05). Results from this study suggests that rhizosphere acidification and the exudation of high amounts of DOM with great metal extracting ability might be two important mechanisms by which HE S. alfredii is involved in activating metal in the rhizosphere. PMID:20970251

  3. Combined endophytic inoculants enhance nickel phytoextraction from serpentine soil in the hyperaccumulator Noccaea caerulescens

    PubMed Central

    Visioli, Giovanna; Vamerali, Teofilo; Mattarozzi, Monica; Dramis, Lucia; Sanangelantoni, Anna M.

    2015-01-01

    This study assesses the effects of specific bacterial endophytes on the phytoextraction capacity of the Ni-hyperaccumulator Noccaea caerulescens, spontaneously growing in a serpentine soil environment. Five metal-tolerant endophytes had already been selected for their high Ni tolerance (6 mM) and plant growth promoting ability. Here we demonstrate that individual bacterial inoculation is ineffective in enhancing Ni translocation and growth of N. caerulescens in serpentine soil, except for specific strains Ncr-1 and Ncr-8, belonging to the Arthrobacter and Microbacterium genera, which showed the highest indole acetic acid production and 1-aminocyclopropane-1-carboxylic acid-deaminase activity. Ncr-1 and Ncr-8 co-inoculation was even more efficient in promoting plant growth, soil Ni removal, and translocation of Ni, together with that of Fe, Co, and Cu. Bacteria of both strains densely colonized the root surfaces and intercellular spaces of leaf epidermal tissue. These two bacterial strains also turned out to stimulate root length, shoot biomass, and Ni uptake in Arabidopsis thaliana grown in MS agar medium supplemented with Ni. It is concluded that adaptation of N. caerulescens in highly Ni-contaminated serpentine soil can be enhanced by an integrated community of bacterial endophytes rather than by single strains; of the former, Arthrobacter and Microbacterium may be useful candidates for future phytoremediation trials in multiple metal-contaminated sites, with possible extension to non-hyperaccumulator plants. PMID:26322074

  4. Spatial Imaging, Speciation, and Quantification of Selenium in theHyperaccumulator Plants Astragalus bisulcatus and Stanleya pinnata

    SciTech Connect

    Freeman, J.L.; Zhang, L.H.; Marcus, M.A.; Fakra, S.; McGrath,S.P.; Pilon-Smits, E.A.H.

    2006-09-01

    Astragalus bisulcatus and Stanleya pinnata hyperaccumulate selenium (Se) up to 1% of plant dry weight. In the field, Se was mostly present in the young leaves and reproductive tissues of both hyperaccumulators. Microfocused scanning x-ray fluorescence mapping revealed that Se was hyperaccumulated in trichomes in young leaves of A. bisulcatus. None of 10 other elements tested were accumulated in trichomes. Micro x-ray absorption spectroscopy and liquid chromatography-mass spectrometry showed that Se in trichomes was present in the organic forms methylselenocysteine (MeSeCys; 53%) and {gamma}-glutamyl-MeSeCys (47%). In the young leaf itself, there was 30% inorganic Se (selenate and selenite) in addition to 70% MeSeCys. In young S. pinnata leaves, Se was highly concentrated near the leaf edge and surface in globular structures that were shown by energy-dispersive x-ray microanalysis to be mainly in epidermal cells. Liquid chromatography-mass spectrometry revealed both MeSeCys (88%) and selenocystathionine (12%) inside leaf edges. In contrast, both the Se accumulator Brassica juncea and the nonaccumulator Arabidopsis thaliana accumulated Se in their leaf vascular tissues and mesophyll cells. Se in hyperaccumulators appears to be mobile in both the xylem and phloem because Se-treated S. pinnata was found to be highly toxic to phloem-feeding aphids, and MeSeCys was present in the vascular tissues of a S. pinnata young leaf petiole as well as in guttation fluid. The compartmentation of organic selenocompounds in specific storage areas in the plant periphery appears to be a unique property of Se hyperaccumulators. The high concentration of Se in the plant periphery may contribute to Se tolerance and may also serve as an elemental plant defense mechanism.

  5. Nickel Increases Susceptibility of a Nickel Hyperaccumulator to Turnip mosaic virus Micheal A. Davis,* John F. Murphy, and Robert S. Boyd

    E-print Network

    Boyd, Robert S.

    Nickel Increases Susceptibility of a Nickel Hyperaccumulator to Turnip mosaic virus Micheal A of this defense, however, has not been tested with a viral pathogen. Turnip mosaic virus (TuMV) accu- and Europe

  6. Exploring the importance of sulfate transporters and ATP sulphurylases for selenium hyperaccumulation—a comparison of Stanleya pinnata and Brassica juncea (Brassicaceae)

    PubMed Central

    Schiavon, Michela; Pilon, Marinus; Malagoli, Mario; Pilon-Smits, Elizabeth A. H.

    2015-01-01

    Selenium (Se) hyperaccumulation, the capacity of some species to concentrate Se to levels upwards of 0.1% of dry weight, is an intriguing phenomenon that is only partially understood. Questions that remain to be answered are: do hyperaccumulators have one or more Se-specific transporters? How are these regulated by Se and sulfur (S)? In this study, hyperaccumulator Stanleya pinnata was compared with related non-hyperaccumulator Brassica juncea with respect to S-dependent selenate uptake and translocation, as well as for the expression levels of three sulfate/selenate transporters (Sultr) and three ATP sulphurylases (APS). Selenium accumulation went down ~10-fold with increasing sulfate supply in B. juncea, while S. pinnata only had a 2–3-fold difference in Se uptake between the highest (5 mM) and lowest sulfate (0 mM) treatments. The Se/S ratio was generally higher in the hyperaccumulator than the non-hyperaccumulator, and while tissue Se/S ratio in B. juncea largely reflected the ratio in the growth medium, S. pinnata enriched itself up to 5-fold with Se relative to S. The transcript levels of Sultr1;2 and 2;1 and APS1, 2, and 4 were generally much higher in S. pinnata than B. juncea, and the species showed differential transcript responses to S and Se supply. These results indicate that S. pinnata has at least one transporter with significant selenate specificity over sulfate. Also, the hyperaccumulator has elevated expression levels of several sulfate/selenate transporters and APS enzymes, which likely contribute to the Se hyperaccumulation and hypertolerance phenotype. PMID:25688247

  7. Exploring the importance of sulfate transporters and ATP sulphurylases for selenium hyperaccumulation-a comparison of Stanleya pinnata and Brassica juncea (Brassicaceae).

    PubMed

    Schiavon, Michela; Pilon, Marinus; Malagoli, Mario; Pilon-Smits, Elizabeth A H

    2015-01-01

    Selenium (Se) hyperaccumulation, the capacity of some species to concentrate Se to levels upwards of 0.1% of dry weight, is an intriguing phenomenon that is only partially understood. Questions that remain to be answered are: do hyperaccumulators have one or more Se-specific transporters? How are these regulated by Se and sulfur (S)? In this study, hyperaccumulator Stanleya pinnata was compared with related non-hyperaccumulator Brassica juncea with respect to S-dependent selenate uptake and translocation, as well as for the expression levels of three sulfate/selenate transporters (Sultr) and three ATP sulphurylases (APS). Selenium accumulation went down ~10-fold with increasing sulfate supply in B. juncea, while S. pinnata only had a 2-3-fold difference in Se uptake between the highest (5 mM) and lowest sulfate (0 mM) treatments. The Se/S ratio was generally higher in the hyperaccumulator than the non-hyperaccumulator, and while tissue Se/S ratio in B. juncea largely reflected the ratio in the growth medium, S. pinnata enriched itself up to 5-fold with Se relative to S. The transcript levels of Sultr1;2 and 2;1 and APS1, 2, and 4 were generally much higher in S. pinnata than B. juncea, and the species showed differential transcript responses to S and Se supply. These results indicate that S. pinnata has at least one transporter with significant selenate specificity over sulfate. Also, the hyperaccumulator has elevated expression levels of several sulfate/selenate transporters and APS enzymes, which likely contribute to the Se hyperaccumulation and hypertolerance phenotype. PMID:25688247

  8. Evaluation of hyperaccumulator plant species grown in metalliferous sites in Albania

    NASA Astrophysics Data System (ADS)

    Babani, F.; Civici, N.; Mullaj, A.; Kongjika, E.; Ylli, A.

    2007-04-01

    Heavy metal contamination of soils causes serious problems to our society. A small number of interesting plant species have been identified that can grow in soils containing high levels of heavy metals, and can also accumulate these metals to high concentrations in the shoot. The heavy metal contents in root, shoot, leaves and flowers of spontaneous plants grown in metalliferous sites in Albania together with the elemental composition of the native soils were determined by X-ray fluorescence spectrometry. Efficiency of photosynthetic apparatus of analyzed ecotypes was evaluated via chlorophyll fluorescence imaging during induction kinetics. Response of plant root system to the presence of metals, the available pools of metals to plants, effect of plant biomass to phytoextraction, photosynthetic pigment metabolism and chlorophyll fluorescence signature of leaves allowed to characterize hyperaccumulator properties and to detect the variation between selected ecotypes to heavy metal accumulation.

  9. Role of transpiration in arsenic accumulation of hyperaccumulator Pteris vittata L.

    PubMed

    Wan, Xiao-Ming; Lei, Mei; Chen, Tong-Bin; Yang, Jun-Xing; Liu, Hong-Tao; Chen, Yang

    2015-11-01

    Mechanisms of Pteris vittata L. to hyperaccumulate arsenic (As), especially the efficient translocation of As from rhizoids to fronds, are not clear yet. The present study aims to investigate the role of transpiration in the accumulation of As from the aspects of transpiration regulation and ecotypic difference. Results showed that As accumulation of P. vittata increased proportionally with an increase in the As exposure concentration. Lowering the transpiration rate by 28?67 % decreased the shoot As concentration by 19?56 %. Comparison of As distribution under normal treatment and shade treatment indicated that transpiration determines the distribution pattern of As in pinnae. In terms of the ecotypic difference, the P. vittata ecotype from moister and warmer habitat had 40 % higher transpiration and correspondingly 40 % higher shoot As concentration than the ecotype from drier and cooler habitat. Results disclosed that transpiration is the main driver for P. vittata to accumulate and re-distribute As in pinnae. PMID:26081771

  10. Root responses to soil Ni heterogeneity in a hyperaccumulator and a non-accumulator species.

    PubMed

    Moradi, Ahmad B; Conesa, Héctor M; Robinson, Brett H; Lehmann, Eberhard; Kaestner, Anders; Schulin, Rainer

    2009-01-01

    We compared root responses of the Ni-hyperaccumulator plant Berkheya coddii Rossler with the non-accumulator plant Cicer arietinum L. to Ni heterogeneity in soil. We grew plants in growth containers filled with control soil, homogeneously spiked, and heterogeneously spiked soil with Ni concentrations of 62 and 125 mg kg(-1). Neutron radiography (NR) was used to observe the root distribution and the obtained images were analysed to reveal the root volumes in the spiked and unspiked segments of the growth container. There was no significant difference in root distribution pattern of B. coddii among different concentrations of Ni. Unlike B. coddii, the roots of C. arietinum initially grew into the spiked segments. However, the later developing roots did not penetrate the spiked segment suggesting an avoidance strategy. Our results indicate that, B. coddii does not forage towards the Ni-rich patches, although presence of Ni in soil changes its root morphology. PMID:19427726

  11. A Newly Identified Passive Hyperaccumulator Eucalyptus grandis × E. urophylla under Manganese Stress

    PubMed Central

    Xie, Qingqing; Li, Zhenji; Yang, Limin; Lv, Jing; Jobe, Timothy O.; Wang, Qiuquan

    2015-01-01

    Manganese (Mn) is an essential micronutrient needed for plant growth and development, but can be toxic to plants in excess amounts. However, some plant species have detoxification mechanisms that allow them to accumulate Mn to levels that are normally toxic, a phenomenon known as hyperaccumulation. These species are excellent candidates for developing a cost-effective remediation strategy for Mn-polluted soils. In this study, we identified a new passive Mn-hyperaccumulator Eucalyptus grandis × E. urophylla during a field survey in southern China in July 2010. This hybrid can accumulate as much as 13,549 mg/kg DW Mn in its leaves. Our results from Scanning Electron Microscope (SEM) X-ray microanalysis indicate that Mn is distributed in the entire leaf and stem cross-section, especially in photosynthetic palisade, spongy mesophyll tissue, and stem xylem vessels. Results from size-exclusion chromatography coupled with ICP-MS (Inductively coupled plasma mass spectrometry) lead us to speculate that Mn associates with relatively high molecular weight proteins and low molecular weight organic acids, including tartaric acid, to avoid Mn toxicity. Our results provide experimental evidence that both proteins and organic acids play important roles in Mn detoxification in Eucalyptus grandis × E. urophylla. The key characteristics of Eucalyptus grandis × E. urophylla are an increased Mn translocation facilitated by transpiration through the xylem to the leaves and further distribution throughout the leaf tissues. Moreover, the Mn-speciation profile obtained for the first time in different cellular organelles of Eucalyptus grandis × E. urophylla suggested that different organelles have differential accumulating abilities and unique mechanisms for Mn-detoxification. PMID:26327118

  12. A comprehensive set of transcript sequences of the heavy metal hyperaccumulator Noccaea caerulescens

    PubMed Central

    Lin, Ya-Fen; Severing, Edouard I.; te Lintel Hekkert, Bas; Schijlen, Elio; Aarts, Mark G. M.

    2014-01-01

    Noccaea caerulescens is an extremophile plant species belonging to the Brassicaceae family. It has adapted to grow on soils containing high, normally toxic, concentrations of metals such as nickel, zinc, and cadmium. Next to being extremely tolerant to these metals, it is one of the few species known to hyperaccumulate these metals to extremely high concentrations in their aboveground biomass. In order to provide additional molecular resources for this model metal hyperaccumulator species to study and understand the mechanism of adaptation to heavy metal exposure, we aimed to provide a comprehensive database of transcript sequences for N. caerulescens. In this study, 23,830 transcript sequences (isotigs) with an average length of 1025 bp were determined for roots, shoots and inflorescences of N. caerulescens accession “Ganges” by Roche GS-FLEX 454 pyrosequencing. These isotigs were grouped into 20,378 isogroups, representing potential genes. This is a large expansion of the existing N. caerulescens transcriptome set consisting of 3705 unigenes. When translated and compared to a Brassicaceae proteome set, 22,232 (93.2%) of the N. caerulescens isotigs (corresponding to 19,191 isogroups) had a significant match and could be annotated accordingly. Of the remaining sequences, 98 isotigs resembled non-plant sequences and 1386 had no significant similarity to any sequence in the GenBank database. Among the annotated set there were many isotigs with similarity to metal homeostasis genes or genes for glucosinolate biosynthesis. Only for transcripts similar to Metallothionein3 (MT3), clear evidence for an additional copy was found. This comprehensive set of transcripts is expected to further contribute to the discovery of mechanisms used by N. caerulescens to adapt to heavy metal exposure. PMID:24999345

  13. Please cite this article in press as: Lindblom, S.D., et al., Influence of microbial associations on selenium localization and speciation in roots of Astragalus and Stanleya hyperaccumulators. Environ. Exp. Bot. (2012), doi:10.1016/j.envexpbot.2011.12.011

    E-print Network

    2012-01-01

    on selenium localization and speciation in roots of Astragalus and Stanleya hyperaccumulators. Environ. Exp associations on selenium localization and speciation in roots of Astragalus and Stanleya hyperaccumulators a c t Selenium (Se) hyperaccumulator plants can accumulate and tolerate Se up to 1% of their dry

  14. Co-Planting Cd Contaminated Field Using Hyperaccumulator Solanum Nigrum L. Through Interplant with Low Accumulation Welsh Onion.

    PubMed

    Wang, Siqi; Wei, Shuhe; Ji, Dandan; Bai, Jiayi

    2015-01-01

    Monoculture and intercrop of hyperaccumulator Solanum nigrum L. with low accumulation Welsh onion Renbentieganchongwang were conducted. The results showed that the remove ratio of S. nigrum to Cd was about 7% in intercrop plot when top soil (0-20 cm) Cd concentration was 0.45-0.62 mg kg(-1), which did not significantly impact the yield of low accumulation Welsh onion compared to the monoculture. The consistency of remove ratio in practice and theory indicated the remediation of S. nigrum to Cd was significant. The Cd concentration and yield of Welsh onion were not affected by the growth of S. nigrum either in intercrop plot. The Cd concentration in edible parts of Welsh onion was available either. In short, inter-planting hyperaccumulator with low accumulation crop could normally remediate contaminated soil and produce crop (obtain economic benefit), which may be one practical pathway of phytoremediating heavy metal contaminated soil in the future. PMID:25581317

  15. Difference of toxicity and accumulation of methylated and inorganic arsenic in arsenic-hyperaccumulating and -hypertolerant plants.

    PubMed

    Huang, Ze-Chun; Chen, Tong-Bin; Lei, Mei; Liu, Ying-Ru; Hu, Tian-Dou

    2008-07-15

    The arsenic (As) hyperaccumulators, Pteris vittata and Pteris cretica and an As-tolerant plant Boehmeria nivea, were selected to compare the toxicity, uptake, and transportation of inorganic arsenate (As(V)) and its methylated counterpart dimethylarsinic acid (DMA). The XANES method was used to elucidate the effect of As species transformation on As toxicity and accumulation characteristics. Significantly higher toxicity and lower accumulation of DMAthan inorganic As(V) was shown in the As hyperaccumulators and the As-tolerant plant. Reduction of As(V) was commonly found in the plants. Arsenic complexation with thiols, which have less mobility in plants and usually occur in As-tolerant plants, was also found in rhizoids of P. cretica. Plants with greater ability to form As-thiolate have lower ability for upward transport of As. Demethylation of DMA occurred in the three plants. The DMA component decreased from the rhizoids to the fronds in both hyperaccumulators, while this tendency is reverse in B. nivea. PMID:18754355

  16. TU & MA: ARSENIC UPTAKE BY THE HYPERACCUMULATOR LADDER BRAKE 641 reproductive growth of simulated and field-grown soybean. I. Seed-dynamics of N2-fixing, field-growing Alnus glutinosa under elevated

    E-print Network

    Ma, Lena

    TU & MA: ARSENIC UPTAKE BY THE HYPERACCUMULATOR LADDER BRAKE 641 reproductive growth of simulated and nitrogen Effects of Arsenic Concentrations and Forms on Arsenic Uptake by the Hyperaccumulator Ladder Brake of arsenic-contaminated soils has thus become aLadder brake (Pteris vittata L.) is a newly discovered arsenic

  17. Phytomining of valuable metals from waste incineration residues using hyperaccumulator plants

    NASA Astrophysics Data System (ADS)

    Rosenkranz, Theresa; Kisser, Johannes; Gattringer, Heinz; Iordanopoulos-Kisser, Monika; Puschenreiter, Markus

    2015-04-01

    Worldwide the availability of primary sources of certain economically important metals is decreasing, resulting in high supply risks and increasing prices for this materials. Therefore, an alternative way of retrieving these high valuable technical metals is the recycling and use of anthropogenic secondary sources, such as waste incineration residues. Phytomining offers an environmentally sound and cheap technology to recover such metals from secondary sources. Thus, the aim of our research work is to investigate the potential of phytomining from waste incineration slags by growing metal hyperaccumulating plants on this substrates and use the metal enriched biomass as a bio-ore. As a first stage, material from Vienna's waste incineration plants was sampled and analyzed. Residues from municipal wastes as well as residues from hazardous waste incineration and sewage sludge incineration were analyzed. In general, the slags can be characterized by a very high pH, high salinity and high heavy metal concentrations. Our work is targeting the so-called critical raw materials defined by the European Commission in 2014. Thus, the target metal species in our project are amongst others cobalt, chromium, antimony, tungsten, gallium, nickel and selected rare earth elements. This elements are present in the slags at moderate to low concentrations. In order to optimize the substrate for plant growth the high pH and salt content as well as the low nitrogen content in the slags need to be controlled. Thus, different combinations of amendments, mainly from the waste industry, as well as different acidifying agents were tested for conditioning the substrate. Washing the slags with diluted nitric acid turned out to be effective for lowering the pH. The acid treated substrate in combination with material from mechanical biological waste treatment and biochar, is currently under investigation in a greenhouse pot experiment. The experimental setup consists of a full factorial design involving six plant species and an unplanted control as well as two different substrates. Fast growing species (Brassica napus, B. juncea, Nicotiana tabacum) will be harvested after two months, whereas slowly growing hyperaccumulators (Sedum plumbizincicola, Alyssum pintodasilvae) will be harvested after four months of growth. The plant tissue will be analyzed for the accumulation of the target metals. Moreover, the influence of plants on the substrate and solubility of certain metals is going to be evaluated.

  18. Effect of elevated CO2 concentration on photosynthetic characteristics of hyperaccumulator Sedum alfredii under cadmium stress.

    PubMed

    Li, Tingqiang; Tao, Qi; Di, Zhenzhen; Lu, Fan; Yang, Xiaoe

    2015-07-01

    The combined effects of elevated CO2 and cadmium (Cd) on photosynthetic rate, chlorophyll fluorescence and Cd accumulation in hyperaccumulator Sedum alfredii Hance were investigated to predict plant growth under Cd stress with rising atmospheric CO2 concentration. Both pot and hydroponic experiments were conducted and the plants were grown under ambient (350?µL?L(-1)) or elevated (800?µL?L(-1)) CO2 . Elevated CO2 significantly (P?

  19. The Variation of Root Exudates from the Hyperaccumulator Sedum alfredii under Cadmium Stress: Metabonomics Analysis

    PubMed Central

    Luo, Qing; Sun, Lina; Hu, Xiaomin; Zhou, Ruiren

    2014-01-01

    Hydroponic experiments were conducted to investigate the variation of root exudates from the hyperaccumulator Sedum alfredii under the stress of cadmium (Cd). S. alfredii was cultured for 4 days in the nutrient solution spiked with CdCl2 at concentrations of 0, 5, 10, 40, and 400 µM Cd after the pre-culture. The root exudates were collected and analyzed by GC-MS, and 62 compounds were identified. Of these compounds, the orthogonal partial least-squares discrimination analysis (OPLS-DA) showed that there were a distinct difference among the root exudates with different Cd treatments and 20 compounds resulting in this difference were found out. Changing tendencies in the relative content of these 20 compounds under the different Cd treatments were analyzed. These results indicated that trehalose, erythritol, naphthalene, d-pinitol and n-octacosane might be closely related to the Cd stabilization, phosphoric acid, tetradecanoic acid, oxalic acid, threonic acid and glycine could be attributed to the Cd mobilization, and mannitol, oleic acid, 3-hydroxybutanoic acid, fructose, octacosanol and ribitol could copy well with the Cd stress. PMID:25545686

  20. Formation of biomineral iron oxides compounds in a Fe hyperaccumulator plant: Imperata cylindrica (L.) P. Beauv.

    PubMed

    Fuente, V; Rufo, L; Juárez, B H; Menéndez, N; García-Hernández, M; Salas-Colera, E; Espinosa, A

    2016-01-01

    We report a detailed work of composition and location of naturally formed iron biominerals in plant cells tissues grown in iron rich environments as Imperata cylindrica. This perennial grass grows on the Tinto River banks (Iberian Pyritic Belt) in an extreme acidic ecosystem (pH?2.3) with high concentration of dissolved iron, sulphate and heavy metals. Iron biominerals were found at the cellular level in tissues of root, stem and leaf both in collected and laboratory-cultivated plants. Iron accumulated in this plant as a mix of iron compounds (mainly as jarosite, ferrihydrite, hematite and spinel phases) was characterized by X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), Mössbauer spectroscopy (MS), magnetometry (SQUID), electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX; TEM-EDX; HRSTEM). A low fraction of phosphorous was detected in this iron hyperaccumulator plant. Root and rhizomes tissues present a high proportion of ferromagnetic iron oxide compounds. Iron oxides-rich zones are localized in electron dense intra and inter-cellular aggregates that appear as dark deposits covering the inner membrane and organelles of the cell. This study aims to contribute to a better understanding of the mechanisms of accumulation, transport, distribution of iron in Imperata cylindrica. PMID:26592710

  1. High As exposure induced substantial arsenite efflux in As-hyperaccumulator Pteris vittata.

    PubMed

    Chen, Yanshan; Fu, Jing-Wei; Han, Yong-He; Rathinasabapathi, Bala; Ma, Lena Q

    2016-02-01

    Arsenite (AsIII) efflux is an important mechanism for arsenic (As) detoxification in plants. Low AsIII efflux has been observed in As-hyperaccumulator Pteris vittata, which may contribute to its highly efficient As translocation and accumulation; however, the results may be compromised by microbial AsIII oxidation, relatively low As concentration in the medium and short-term As exposure. Here, sterile P. vittata sporophytes were cultivated in sterile medium containing 10, 200 and 500 µM arsenate (AsV) for 28 d. Arsenite efflux to the growth medium and As speciation in P. vittata was investigated. Low AsIII efflux at 12% of AsV uptake was observed at 10 µM AsV, but high AsIII efflux (36-76%) was observed at 200 and 500 µM AsV, with 1987-2397 mg kg(-1) As being accumulated in the fronds. This is the first report to show efficient AsIII efflux in P. vittata. This study showed that P. vittata may use high AsIII efflux to cope with As toxicity under high As exposure, which may be necessary to sustain growth while accumulating As. PMID:26595313

  2. Hyperaccumulator oilcake manure as an alternative for chelate-induced phytoremediation of heavy metals contaminated alluvial soils.

    PubMed

    Mani, Dinesh; Kumar, Chitranjan; Patel, Niraj Kumar

    2015-01-01

    The ability of hyperaccumulator oilcake manure as compared to chelates was investigated by growing Calendula officinalis L for phytoremediation of cadmium and lead contaminated alluvial soil. The combinatorial treatment T6 [2.5 g kg(-1) oilcake manure+5 mmol kg(-1) EDDS] caused maximum cadmium accumulation in root, shoot and flower up to 5.46, 4.74 and 1.37 mg kg(-1) and lead accumulation up to 16.11, 13.44 and 3.17 mg kg(-1), respectively at Naini dump site, Allahabad (S3). The treatment showed maximum remediation efficiency for Cd (RR=0.676%) and Pb (RR=0.202%) at Mumfordganj contaminated site (S2). However, the above parameters were also observed at par with the treatment T5 [2.5 g kg(-1) oilcake manure +2 g kg(-1) humic acid]. Applied EDDS altered chlorophyll-a, chlorophyll-b, and carotene contents of plants while application of oilcake manure enhanced their contents in plant by 3.73-8.65%, 5.81-17.65%, and 7.04-17.19%, respectively. The authors conclude that Calendula officinalis L has potential to be safely grown in moderately Cd and Pb-contaminated soils and application of hyperaccumulator oilcake manure boosts the photosynthetic pigments of the plant, leading to enhanced clean-up of the cadmium and lead-contaminated soils. Hence, the hyperaccumulator oilcake manure should be preferred over chelates for sustainable phytoremediation through soil-plant rhizospheric process. PMID:25397984

  3. Chromate and phosphate inhibited each other's uptake and translocation in arsenic hyperaccumulator Pteris vittata L.

    PubMed

    de Oliveira, Letúzia M; Lessl, Jason T; Gress, Julia; Tisarum, Rujira; Guilherme, Luiz R G; Ma, Lena Q

    2015-02-01

    We investigated the effects of chromate (CrVI) and phosphate (P) on their uptake and translocation in As-hyperaccumulator Pteris vittata (PV). Plants were exposed to 1) 0.10 mM CrVI and 0, 0.25, 1.25, or 2.50 mM P or 2) 0.25 mM P and 0, 0.50, 2.5 or 5.0 mM CrVI for 24 h in hydroponics. PV accumulated 2919 mg/kg Cr in the roots at CrVI?.??, and 5100 and 3500 mg/kg P in the fronds and roots at P?.??. When co-present, CrVI and P inhibited each other's uptake in PV. Increasing P concentrations reduced Cr root concentrations by 62-82% whereas increasing CrVI concentrations reduced frond P concentrations by 52-59% but increased root P concentrations by 11-15%. Chromate reduced P transport, with more P being accumulated in PV roots. Though CrVI was supplied, 64-78% and 92-93% CrIII were in PV fronds and roots. Based on X-ray diffraction, Cr?O? was detected in the roots confirming CrVI reduction to CrIII by PV. In short, CrVI and P inhibited each other in uptake and translocation by PV, and CrVI reduction to CrIII in PV roots served as its detoxification mechanism. The finding helps to understand the interactions of P and Cr during their uptake in PV. PMID:25434865

  4. Functional analysis of the three HMA4 copies of the metal hyperaccumulator Arabidopsis halleri.

    PubMed

    Nouet, Cécile; Charlier, Jean-Benoit; Carnol, Monique; Bosman, Bernard; Farnir, Frédéric; Motte, Patrick; Hanikenne, Marc

    2015-09-01

    In Arabidopsis halleri, the HMA4 gene has an essential function in Zn/Cd hypertolerance and hyperaccumulation by mediating root-to-shoot translocation of metals. Constitutive high expression of AhHMA4 results from a tandem triplication and cis-activation of the promoter of all three copies. The three AhHMA4 copies possess divergent promoter sequences, but highly conserved coding sequences, and display identical expression profiles in the root and shoot vascular system. Here, an AhHMA4::GFP fusion was expressed under the control of each of the three A. halleri HMA4 promoters in a hma2hma4 double mutant of A. thaliana to individually examine the function of each AhHMA4 copy. The protein showed non-polar localization at the plasma membrane of the root pericycle cells of both A. thaliana and A. halleri. The expression of each AhHMA4::GFP copy complemented the severe Zn-deficiency phenotype of the hma2hma4 mutant by restoring root-to-shoot translocation of Zn. However, each copy had a different impact on metal homeostasis in the A. thaliana genetic background: AhHMA4 copies 2 and 3 were more highly expressed and provided higher Zn tolerance in roots and accumulation in shoots than copy 1, and AhHMA4 copy 3 also increased Cd tolerance in roots. These data suggest a certain extent of functional differentiation among the three A. halleri HMA4 copies, stemming from differences in expression levels rather than in expression profile. HMA4 is a key node of the Zn homeostasis network and small changes in expression level can have a major impact on Zn allocation to root or shoot tissues. PMID:26044091

  5. Functional analysis of the three HMA4 copies of the metal hyperaccumulator Arabidopsis halleri

    PubMed Central

    Nouet, Cécile; Charlier, Jean-Benoit; Carnol, Monique; Bosman, Bernard; Farnir, Frédéric; Motte, Patrick; Hanikenne, Marc

    2015-01-01

    In Arabidopsis halleri, the HMA4 gene has an essential function in Zn/Cd hypertolerance and hyperaccumulation by mediating root-to-shoot translocation of metals. Constitutive high expression of AhHMA4 results from a tandem triplication and cis-activation of the promoter of all three copies. The three AhHMA4 copies possess divergent promoter sequences, but highly conserved coding sequences, and display identical expression profiles in the root and shoot vascular system. Here, an AhHMA4::GFP fusion was expressed under the control of each of the three A. halleri HMA4 promoters in a hma2hma4 double mutant of A. thaliana to individually examine the function of each AhHMA4 copy. The protein showed non-polar localization at the plasma membrane of the root pericycle cells of both A. thaliana and A. halleri. The expression of each AhHMA4::GFP copy complemented the severe Zn-deficiency phenotype of the hma2hma4 mutant by restoring root-to-shoot translocation of Zn. However, each copy had a different impact on metal homeostasis in the A. thaliana genetic background: AhHMA4 copies 2 and 3 were more highly expressed and provided higher Zn tolerance in roots and accumulation in shoots than copy 1, and AhHMA4 copy 3 also increased Cd tolerance in roots. These data suggest a certain extent of functional differentiation among the three A. halleri HMA4 copies, stemming from differences in expression levels rather than in expression profile. HMA4 is a key node of the Zn homeostasis network and small changes in expression level can have a major impact on Zn allocation to root or shoot tissues. PMID:26044091

  6. Current Biology 21, 14401449, September 13, 2011 2011 Elsevier Ltd All rights reserved DOI 10.1016/j.cub.2011.07.033 Selenium Hyperaccumulators Facilitate

    E-print Network

    .1016/j.cub.2011.07.033 Article Selenium Hyperaccumulators Facilitate Selenium-Tolerant Neighbors via surrounding selenium (Se) hyperaccumula- tor plants was shown earlier to be enriched in Se, impairing selenium (Se) is a trace element for many animals as a component of selenoproteins, which are redox

  7. Improved cadmium uptake and accumulation in the hyperaccumulator Sedum alfredii: the impact of citric acid and tartaric acid* #

    PubMed Central

    Lu, Ling-li; Tian, Sheng-ke; Yang, Xiao-e; Peng, Hong-yun; Li, Ting-qiang

    2013-01-01

    The elucidation of a natural strategy for metal hyperaccumulation enables the rational design of technologies for the clean-up of metal-contaminated soils. Organic acid has been suggested to be involved in toxic metallic element tolerance, translocation, and accumulation in plants. The impact of exogenous organic acids on cadmium (Cd) uptake and translocation in the zinc (Zn)/Cd co-hyperaccumulator Sedum alfredii was investigated in the present study. By the addition of organic acids, short-term (2 h) root uptake of 109Cd increased significantly, and higher 109Cd contents in roots and shoots were noted 24 h after uptake, when compared to controls. About 85% of the 109Cd taken up was distributed to the shoots in plants with citric acid (CA) treatments, as compared with 75% within controls. No such effect was observed for tartaric acid (TA). Reduced growth under Cd stress was significantly alleviated by low CA. Long-term application of the two organic acids both resulted in elevated Cd in plants, but the effects varied with exposure time and levels. The results imply that CA may be involved in the processes of Cd uptake, translocation and tolerance in S. alfredii, whereas the impact of TA is mainly on the root uptake of Cd. PMID:23365009

  8. Selenium biofortification of broccoli and carrots grown in soil amended with Se-enriched hyperaccumulator Stanleya pinnata.

    PubMed

    Bañuelos, Gary S; Arroyo, Irvin; Pickering, Ingrid J; Yang, Soo In; Freeman, John L

    2015-01-01

    Amending soils with Se-hyperaccumulator plant derived sources of selenium (Se) may be useful for increasing the Se content in food crops in Se-deficient regions of the world. In this study we evaluated total Se and the different chemical species of Se in broccoli and carrots grown in soils amended with ground shoots of the Se-hyperaccumulator Stanleyapinnata. With increasing application rates of S. pinnata, total plant Se concentrations increased to nutritionally ideal levels inside edible parts. Selenium compounds in aqueous extracts were analyzed by SAX-HPLC-ICPMS and identified as a variety of mainly organic-Se forms. Together with bulk Se K-edge X-ray absorption near-edge structure (XANES) analysis performed on broccoli florets, carrot roots and shoots, dried ground S. pinnata, and the amended soil at post-plant, we demonstrate that Se-enriched S. pinnata is valuable as a soil amendment for enriching broccoli and carrots with healthful forms of organic-Se. PMID:25053099

  9. Characterization of a Selenium-Tolerant Rhizosphere Strain from a Novel Se-Hyperaccumulating Plant Cardamine hupingshanesis

    PubMed Central

    Yuan, Linxi; Luo, Lei; Yin, Xuebin

    2014-01-01

    A novel selenium- (Se-) hyperaccumulating plant, Cardamine hupingshanesis, accumulating Se as a form of SeCys2, was discovered in Enshi, Hubei, China, which could not be explained by present selenocysteine methyltransferase (SMT) theory. However, it is interesting to investigate if rhizosphere bacteria play some roles during SeCys2 accumulation. Here, one Se-tolerant rhizosphere strain, Microbacterium oxydans, was isolated from C. hupingshanesis. Phylogenetic analysis and 16S rRNA gene sequences determined the strain as a kind of Gram positive bacillus and belonged to the family Brevibacterium frigoritolerans. Furthermore, Se tolerance test indicated the strain could grow in extreme high Se level of 15.0?mg?Se?L?1. When exposed to 1.5?mg?Se L?1, SeCys2 was the predominant Se species in the bacteria, consistent with the Se species in C. hupingshanesis. This coincidence might reveal that this strain played some positive effect in SeCys2 accumulation of C. hupingshanesis. Moreover, when exposed to 1.5?mg Se?L?1 or 15.0?mg Se?L?1, As absorption diminished in the logarithmic phase. In contrast, As absorption increased when exposed to 7.5?mg Se?L?1, indicating As metabolism processes could be affected by Se on this strain. The present study provided a sight on the role of rhizosphere bacteria during Se accumulation for Se-hyperaccumulating plant. PMID:25478582

  10. Root development of non-accumulating and hyperaccumulating plants in metal-contaminated soils amended with biochar.

    PubMed

    Rees, Frédéric; Sterckeman, Thibault; Morel, Jean Louis

    2016-01-01

    Biochar may be used as an amendment in contaminated soils in phytoremediation processes. The mechanisms controlling plant metal uptake in biochar-amended soils remain however unclear. This work aimed at evaluating the influence of biochar on root development and its consequence on plant metal uptake, for two non-hyperaccumulating plants (Zea mays and Lolium perenne) and one hyperaccumulator of Cd and Zn (Noccaea caerulescens). We conducted rhizobox experiments using one acidic and one alkaline soil contaminated with Cd, Pb and Zn. Biochar was present either homogeneously in the whole soil profile or localized in specific zones. A phenomenon of root proliferation specific to biochar-amended zones was seen on the heterogeneous profiles of the acidic soil and interpreted by a decrease of soil phytotoxicity in these zones. Biochar amendments also favored root growth in the alkaline soil as a result of the lower availability of certain nutrients in the amended soil. This increase of root surface led to a higher accumulation of metals in roots of Z.mays in the acidic soil and in shoots of N. caerulescens in the alkaline soil. In conclusion, biochar can have antagonist effects on plant metal uptake by decreasing metal availability, on one hand, and by increasing root surface and inducing root proliferation, on the other hand. PMID:25912633

  11. Uptake of antimonite and antimonate by arsenic hyperaccumulator Pteris vittata: Effects of chemical analogs and transporter inhibitor.

    PubMed

    Tisarum, Rujira; Chen, Yanshan; Dong, Xiaoling; Lessl, Jason T; Ma, Lena Q

    2015-11-01

    Antimonite (SbIII) is transported into plants via aquaglyceroporin channels but it is unknown in As-hyperaccumulator Ptreis vittata (PV). We tested the effects of SbIII analogs (arsenite-AsIII, glycerol, silicic acid-Si, and, glucose), antimonate (SbV) analog (phosphate-P), and aquaglyceroporin transporter inhibitor (silver, Ag) on the uptake of SbIII or SbV by PV gametophytes. PV gametophytes were grown in 20% Hoagland solution containing 65 ?M SbIII or SbV and increasing concentrations of analogs at 65-6500 ?M for 2 h or 4 h under sterile condition. After exposing to 65 ?M Sb for 2 h, PV accumulated 767 mg/kg Sb in SbIII treatment and 419 mg/kg in SbV treatment. SbIII uptake by PV gametophytes was not impacted by glycerol or AsIII nor aquaglyceroporin inhibitor Ag during 2 h exposure. While Si increased SbIII uptake and glucose decreased SbIII uptake by PV gametophytes, the impact disappeared during 4 h exposure. Under P-sufficient condition, P increased SbIII uptake and decreased SbV uptake during 2 h exposure, but the effect again disappeared after 4 h. After being P-starved for 2 weeks, P decreased SbIII with no effect on SbV uptake during 2 h exposure. Our results indicated that: 1) PV gametophytes could serve as an efficient model to study Sb uptake, and 2) unique SbIII uptake by PV may be related to its trait of As hyperaccumulation. PMID:26142750

  12. Elucidating the selenium and arsenic metabolic pathways following exposure to the non-hyperaccumulating Chlorophytum comosum, spider plant

    PubMed Central

    Afton, Scott E.; Catron, Brittany; Caruso, Joseph A.

    2009-01-01

    Although many studies have investigated the metabolism of selenium and arsenic in hyperaccumulating plants for phytoremediation purposes, few have explored non-hyperaccumulating plants as a model for general contaminant exposure to plants. In addition, the result of simultaneous supplementation with selenium and arsenic has not been investigated in plants. In this study, Chlorophytum comosum, commonly known as the spider plant, was used to investigate the metabolism of selenium and arsenic after single and simultaneous supplementation. Size exclusion and ion-pairing reversed phase liquid chromatography were coupled to an inductively coupled plasma mass spectrometer to obtain putative metabolic information of the selenium and arsenic species in C. comosum after a mild aqueous extraction. The chromatographic results depict that selenium and arsenic species were sequestered in the roots and generally conserved upon translocation to the leaves. The data suggest that selenium was directly absorbed by C. comosum roots when supplemented with SeVI, but a combination of passive and direct absorption occurred when supplemented with SeIV due to the partial oxidation of SeIV to SeVI in the rhizosphere. Higher molecular weight selenium species were more prevalent in the roots of plants supplemented with SeIV, but in the leaves of plants supplemented with SeVI due to an increased translocation rate. When supplemented as AsIII, arsenic is proposed to be passively absorbed as AsIII and partially oxidized to AsV in the plant root. Although total elemental analysis demonstrates a selenium and arsenic antagonism, a compound containing selenium and arsenic was not present in the general aqueous extract of the plant. PMID:19273464

  13. Hyperaccumulator of Pb in native plants growing on Peruvian mine tailings

    NASA Astrophysics Data System (ADS)

    Bech, Jaume; Roca, Nuria; Boluda, Rafael; Tume, Pedro; Duran, Paola; Poma, Wilfredo; Sanchez, Isidoro

    2014-05-01

    Tailings usually provide an unfavourable substrate for plant growth because of their extreme pH, low organic matter and nutrients, high concentrations of trace elements and physical disturbance, such as bad soil structure, and low water availability. Heavy metal contamination has also been one serious problem in the vicinity of mine sites due to the discharge and dispersion of mine-waste materials into the ecosystem. Moreover, Pb is considered a target metal when undertaking soil remediation, because it is usually quite immobile and not readily accumulated in upper plant parts. The presence of vegetation reduces water and wind erosion, which may decrease the downward migration of contaminants into the groundwater and improve aesthetical aspects. Plants growing on naturally metal-enriched soils are of particular interest in this perspective, since they are genetically tolerant to high metal concentrations, have an excellent adaptation to this multi-stress environment. Efficient phytoextraction requires plant species combining both high metal tolerance and elevated capacity for metal uptake and metal translocation to easily harvestable plant organs (e.g. shoots). Soil and plant samples were taken in Peru, at a polymetallic mine (mainly Ag, Pb and Cu) in Cajamarca Province, Hualgayoc district. Top soils (0-20 cm) were analysed for physical and chemical properties by standard methods. Total Pb concentrations in top soils were determined by ICP-OES. Pb content in plants were analysed separately (aerial and root system) by ICP-MS. Ti content was used as an indicator for contamination of plant samples with soil particles. Translocation Factor (TF) and Shoot Accumulation Factor (SAF) were determined to assess the tolerance strategies developed by these species and to evaluate their potential for phytoremediation purposes. The non-polluted soils had near neutral pH (6.8±0.1), a great content of organic carbon (42 ± 4.0 g•kg-1) and a silt loamy texture. Soil and plant samples were taken at four locations (CA1, CA2, CA3, CA4) with different levels of Pb. The Pb soil content (mean ± standard deviation) in mg•kg-1 is as follows: CA1 3992 ± 301; CA2 10128 ± 2247, CA3 14197 ± 895, CA4 16060 ± 810. The non-polluted value around the mine was Pb 124 mg•kg-1. Unusual elevated concentrations of Pb (over 1000 mg kg-1) and TF greater than one were detected in shoots of 6 different plants species (Ageratina sp., Achirodine alata, Cortaderia apalothica, Epilobium denticulatum, Taraxacum officinalis and Trifolium repens). The location CA4 has the maximum content of Pb in the shoots of Ageratina sp. (5045±77 mg•kg-1), C. apalothica (3367±188 mg•kg-1), E. denticulatum (13599±848 mg•kg-1), T. officinalis (2533±47 mg•kg-1) and T. repens (2839±231 mg•kg-1). However, the BF (Bioaccumulation Factor) was smaller than one. Despite the low BF index, the great TFs for Pb indicate that these plant species effectively translocate this metal (i.e., 2.4 for Ageratina sp., 2.3 for C. apalothica, 1.6 for T. repens, 1.5 for A. alata, 1.3 for T. officinalis and 1.2 for E. denticulatum). It seems that the BF is not a reliable index when the metal soil concentration is extremely large. Controlled-environment studies must be performed to definitively confirm the Pb hyperaccumulation character of cited plant species.

  14. Recovering metals from sewage sludge, waste incineration residues and similar substances with hyperaccumulative plants

    NASA Astrophysics Data System (ADS)

    Kisser, Johannes; Gattringer, Heinz; Iordanopoulos-Kisser, Monika

    2015-04-01

    Sewage sludges as well as ashes from waste incineration plants are known accumulation sinks of many elements that are either important nutrients for biological organisms (phosphorus, potassium, magnesium, etc.) or valuable metals when considered on their own in pure form (nickel, chrome, zinc, etc.); they are also serious pollutants when they occur in wild mixtures at localized anthropogenic end- of-stream points. Austria and many other countries have to import up to 90% of the material inputs of metals from abroad. These primary resources are becoming more expensive as they become more scarce and remaining deposits more difficult to mine, which is a serious concern for industrialized nations. Basic economic and strategic reasoning demands an increase in recycling activities and waste minimization. Technologies to recover metals in a reasonable and economically relevant manner from very diffuse sources are practically non-existent or require large amounts of energy and chemicals, which pose environmental risks. On the other hand agriculture uses large volumes of mineral fertilizers, which are often sourced from mines as well, and thus are also subject to the same principle of finiteness and potential shortage in supply. These converted biological nutrients are taken up by crops and through the food chain and human consumption end up in sewage systems and in wastewater treatment plants in great quantities. The metabolized nutrients mostly do not return to agriculture, but due to contamination with heavy metals are diverted to be used as construction aggregates or are thermally treated and end up rather uselessly in landfills. The project BIO-ORE aimed to explore new pathways to concentrate metals from diluted sources such as sewage sludge and wastewater by using highly efficient biological absorption and transport mechanisms. These enzymatic systems from plants work with very little energy input. The process is called bioaccumulation and can be most effectively observed in so-called hyperaccumulating metalophytes, which are studied for its suitability to be incorporated in metal recovery processes of elements that diffusely occur in different waste streams. In a systematic series of tests under laboratory conditions the accumulation behaviour for many different elements including rare earth metals of a selection of candidate plants growing on sewage sludge, incineration residues and industrial leftovers was assessed (quantitavely and qualitatively). Growth performance of these plants as well as the most suitable substrate properties were evaluated. The results of this project provided the groundwork for further research and development steps that might bring to practical implementation a technological option with potentially huge benefits: The recovery of valuable metal resources from sewage sludge, incineration ashes and metal rich wastewaters by environmentally friendly and low energy means. Simultaneous decontamination of the input substrates from heavy metals, opening the possibility for these nutrient streams to be redirected to biological regeneration processes (for example use as fertilizers in agriculture) without fear of polluting soils with heavy metal loads. Generation of biomass on contaminated substrates can yield usable energy surplus through incineration during or after processing.

  15. Subcellular distribution of rare earth elements and characterization of their binding species in a newly discovered hyperaccumulator Pronephrium simplex.

    PubMed

    Lai, Ying; Wang, Qiuquan; Yang, Limin; Huang, Benli

    2006-08-15

    Subcellular distribution of rare earth elements (REEs, including 14 lanthanides and yttrium) in a newly discovered REE hyperaccumulator, Pronephrium simplex (P. simplex), was determined by a chemical sequence extraction followed by ICP-MS analysis. Results showed that most REEs are associated with cell wall and proteins, and REEs concentration in the proteins, 2899.5mugg(-1), is much higher than those in the cell wall; in the chloroplast of P. simplex, REEs distribute almost equally in chloroplast membrane and thylakoid, while most REEs in the thylakoid are binding with photosystem II (PS II); a new REE-binding peptide in the lamina of P. simplex, which can accumulate REEs up to 3000mugg(-1) and has higher affinity with light REEs, was characterized, indicating that its molecular mass is 5073Da, and may have beta-sheet structure; isoelectrofocusing electrophoretic photograph indicated that it is acidic peptide with IP of 3.7. Such information should be useful for understanding of both the storage and physiological role of REEs in P. simplex and further studies on the phytoremediation of REEs contaminated environments. PMID:18970723

  16. The Hyperaccumulator Alyssum murale uses Complexation with Nitrogen and Oxygen Donor Ligands for Ni Transport and Storage

    SciTech Connect

    McNear, Jr., D.; Chanay, R; Sparks, D

    2010-01-01

    The Kotodesh genotype of the nickel (Ni) hyperaccumulator Alyssum murale was examined to determine the compartmentalization and internal speciation of Ni, and other elements, in an effort to ascertain the mechanism used by this plant to tolerate extremely high shoot (stem and leaf) Ni concentrations. Plants were grown either hydroponically or in Ni enriched soils from an area surrounding an historic Ni refinery in Port Colborne, Ontario, Canada. Electron probe micro-analysis (EPMA) and synchrotron based micro X-ray fluorescence ({mu}-SXRF) spectroscopy were used to determine the metal distribution and co-localization and synchrotron X-ray and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopies were used to determine the Ni speciation in plant parts and extracted sap. Nickel is concentrated in the dermal leaf and stem tissues of A. murale bound primarily to malate along with other low molecular weight organic ligands and possibly counter anions (e.g., sulfate). Ni is present in the plant sap and vasculature bound to histidine, malate and other low molecular weight compounds. The data presented herein supports a model in which Ni is transported from the roots to the shoots complexed with histidine and stored within the plant leaf dermal tissues complexed with malate, and other low molecular weight organic acids or counter-ions.

  17. Arsenic transformation and plant growth promotion characteristics of As-resistant endophytic bacteria from As-hyperaccumulator Pteris vittata.

    PubMed

    Xu, Jia-Yi; Han, Yong-He; Chen, Yanshan; Zhu, Ling-Jia; Ma, Lena Q

    2016-02-01

    The ability of As-resistant endophytic bacteria in As transformation and plant growth promotion was determined. The endophytes were isolated from As-hyperaccumulator Pteris vittata (PV) after growing for 60 d in a soil containing 200 mg kg(-1) arsenate (AsV). They were isolated in presence of 10 mM AsV from PV roots, stems, and leaflets, representing 4 phyla and 17 genera. All endophytes showed at least one plant growth promoting characteristics including IAA synthesis, siderophore production and P solubilization. The root endophytes had higher P solubilization ability than the leaflet (60.0 vs. 18.3 mg L(-1)). In presence of 10 mM AsV, 6 endophytes had greater growth than the control, suggesting As-stimulated growth. Furthermore, root endophytes were more resistant to AsV while the leaflet endophytes were more tolerant to arsenite (AsIII), which corresponded to the dominant As species in PV tissues. Bacterial As resistance was positively correlated to their ability in AsV reduction but not AsIII oxidation. The roles of those endophytes in promoting plant growth and As resistance in P. vittata warrant further investigation. PMID:26469935

  18. Arsenic uptake, arsenite efflux and plant growth in hyperaccumulator Pteris vittata: Role of arsenic-resistant bacteria.

    PubMed

    Han, Yong-He; Fu, Jing-Wei; Chen, Yanshan; Rathinasabapathi, Bala; Ma, Lena Q

    2016-02-01

    Bacteria-mediated arsenic (As) transformation and their impacts on As and P uptake and plant growth in As-hyperaccumulator Pteris vittata (PV) were investigated under sterile condition. All As-resistant bacteria (9 endophytic and 6 rhizospheric) were As-reducers except one As-oxidizer. After growing two months in media with 37.5 mg kg(-1) AsV, As concentrations in the fronds and roots were 3655-5389 (89-91% AsIII) and 971-1467 mg kg(-1) (41-73% AsIII), corresponding to 22-52% decrease in the As in the media. Bacterial inoculation enhanced As and P uptake by up to 47 and 69%, and PV growth by 20-74%, which may be related to elevated As and P in plants (r = 0.88-0.97, p < 0.05). Though AsV was supplied, 95% of the As in the bacteria-free media was AsIII, suggesting efficient efflux of AsIII by PV roots (120 µg g(-1) root fw). This was supported by the fact that no AsV was detected in media inoculated with As-reducers while 95% of AsV was detected with As-oxidizer. Our data showed that, under As-stress, PV reduced As toxicity by efficient AsIII efflux into media and AsIII translocation to the fronds, and bacteria benefited PV growth probably via enhanced As and P uptake. PMID:26547029

  19. Accumulation of Pb, Cd, Cu and Zn in plants and hyperaccumulator choice in Lanping lead-zinc mine area, China.

    PubMed

    Yanqun, Zu; Yuan, Li; Schvartz, Christian; Langlade, Laurent; Fan, Liu

    2004-06-01

    A field survey of higher terrestrial plants growing on Lanping lead-zinc mine, China were conducted to identify species accumulating exceptionally large concentrations of Pb, Cd, Cu and Zn of 20 samples of 17 plant species. Concentrations of Pb and Zn in soil and in plant were higher than that of Cu and Cd. Significant difference was observed among the average concentrations of four heavy metals in plants (except Cd and Cu) and in soil (except Pb and Zn) (P<0.05). For the enrichment coefficient of the four heavy metals in plant, the order of average was Pbtree>herbaceous, and herbaceous grew in soil with the highest concentrations of four heavy metals. In different areas, the concentrations of Pb, Cd, Cu and Zn in plants and soils and enrichment coefficient were different. Plants in Paomaping had more accumulating ability to Pb, Cd and Zn, and plants in Jinfeng River had more accumulating ability to Cu. Six plant species, i.e. S. cathayana, Lithocarpus dealbatus, L. plyneura, Fargesia dura, Arundinella yunnanensis and R. annae in Paomaping, had high accumulation capacity. R. annae in Paomaping had hyperaccumulating capacity to Pb, Cd and Zn, L. plyneura to Pb and Cd, and S. cathayana to Cd, respectively. PMID:15031017

  20. Evidence of various mechanisms of Cd sequestration in the hyperaccumulator Arabidopsis halleri, the non-accumulator Arabidopsis lyrata, and their progenies by combined synchrotron-based techniques.

    PubMed

    Isaure, Marie-Pierre; Huguet, Stéphanie; Meyer, Claire-Lise; Castillo-Michel, Hiram; Testemale, Denis; Vantelon, Delphine; Saumitou-Laprade, Pierre; Verbruggen, Nathalie; Sarret, Géraldine

    2015-06-01

    Arabidopsis halleri is a model plant for Zn and Cd hyperaccumulation. The objective of this study was to determine the relationship between the chemical forms of Cd, its distribution in leaves, and Cd accumulation and tolerance. An interspecific cross was carried out between A. halleri and the non-tolerant and non-hyperaccumulating relative A. lyrata providing progenies segregating for Cd tolerance and accumulation. Cd speciation and distribution were investigated using X-ray absorption spectroscopy and microfocused X-ray fluorescence. In A. lyrata and non-tolerant progenies, Cd was coordinated by S atoms only or with a small contribution of O groups. Interestingly, the proportion of O ligands increased in A. halleri and tolerant progenies, and they were predominant in most of them, while S ligands were still present. Therefore, the binding of Cd with O ligands was associated with Cd tolerance. In A. halleri, Cd was mainly located in the xylem, phloem, and mesophyll tissue, suggesting a reallocation process for Cd within the plant. The distribution of the metal at the cell level was further discussed. In A. lyrata, the vascular bundles were also Cd enriched, but the epidermis was richer in Cd as compared with the mesophyll. Cd was identified in trichomes of both species. This work demonstrated that both Cd speciation and localization were related to the tolerance character of the plant. PMID:25873676

  1. The long-term variation of Cd and Zn hyperaccumulation by Noccaea spp and Arabidopsis halleri plants in both pot and field conditions.

    PubMed

    Tlustoš, Pavel; B?endová, Kate?ina; Száková, Ji?ina; Najmanová, Jana; Koubová, Kate?ina

    2016-02-01

    Three Cd and Zn hyperaccumulating plant species Noccaea caerulescens Noccaea praecox and Arabidopsis halleri (Brassicacceae) were cultivated in seven subsequent vegetation seasons in both pot and field conditions in soil highly contaminated with Cd, Pb, and Zn. The results confirmed the hyperaccumulation ability of both plant species, although A. halleri showed lower Cd uptake compared to N. caerulescens. Conversely, Pb phytoextraction was negligible for both species in this case. Because of the high variability in plant yield and element contents in the aboveground biomass of plants, great variation in Cd and Zn accumulation was observed during the experiment. The extraction ability in field conditions varied in the case of Cd from 0.2 to 2.9 kg ha(-1) (N. caerulescens) and up to 0.15 kg ha(-1) (A. halleri), and in the case of Zn from 0.2 to 6.4 kg ha(-1) (N. caerulescens) and up to 13.8 kg.ha(-1) (A. halleri). Taking into account the 20 cm root zone of the soil, the plants were able to extract up to 4.1% Cd and 0.2% Zn in one season. However, cropping measures should be optimized to improve and stabilize the long-term phytoextraction potential of these plants. PMID:26280307

  2. Increased ecological risk due to the hyperaccumulation of As in Pteris cretica during the phytoremediation of an As-contaminated site.

    PubMed

    Jeong, Seulki; Moon, Hee Sun; Nam, Kyoungphile

    2015-03-01

    Ecological risk due to the hyperaccumulation of As in Pteris cretica during phytoremediation was evaluated at an abandoned As-contaminated site. Five receptor groups representing terrestrial invertebrates, avian insectivores, small mammals, herbivores, and omnivores were selected as potentially affected ecological receptors. Soil and food ingestion were considered as major exposure pathways. Phytoremediation was performed with P.cretica only and with both P.cretica and siderophores to enhance plant uptake of As. Ecological hazard index (EHI) values for the small mammal greatly exceeded 1.0 even after three weeks of growth regardless of siderophore application, probably due to its limited home range. For the mammalian herbivore, which mainly consumes plant foliage, the EHI values were greater than 5.73 after seven weeks without siderophore application, but the value increased sharply to 29.3 at seven weeks when siderophores were applied. This increased risk could be attributed to the facilitated translocation of As from roots to stems and leaves in P.cretica. Our results suggest that, when a phytoremediation strategy is considered for metals remediation, its ecological consequences should be taken into account to prevent the spread of hyperaccumulated heavy metals throughout the food chain of ecological receptors. Uncertainties involved in the ecological risk assessment process were also discussed. PMID:25441929

  3. Rhizobium metallidurans sp. nov., a symbiotic heavy metal resistant bacterium isolated from the Anthyllis vulneraria Zn-hyperaccumulator.

    PubMed

    Grison, Claire M; Jackson, Stephen; Merlot, Sylvain; Dobson, Alan; Grison, Claude

    2015-05-01

    A Gram-stain-negative, aerobic, rod-shaped, non-spore-forming bacterium (ChimEc512(T)) was isolated from 56 host seedlings of the hyperaccumulating Anthyllis vulneraria legume, which was on an old zinc mining site at Les Avinières, Saint-Laurent-Le-Minier, Gard, South of France. On the basis of 16S rRNA gene sequence similarities, strain ChimEc512(T) was shown to belong to the genus Rhizobium and to be most closely related to Rhizobium endophyticum CCGE 2052(T) (98.4%), Rhizobium tibeticum CCBAU 85039(T) (98.1%), Rhizobium grahamii CCGE 502(T) (98.0%) and Rhizobium mesoamericanum CCGE 501(T) (98.0%). The phylogenetic relationships of ChimEc512(T) were confirmed by sequencing and analyses of recA and atpD genes. DNA-DNA relatedness values of strain ChimEc512(T) with R. endophyticum CCGE 2052(T), R. tibeticum CCBAU 85039(T), R. mesoamericanum CCGE 52(T), Rhizobium grahamii CCGE 502(T), Rhizobium etli CCBAU 85039(T) and Rhizobium radiobacter KL09-16-8-2(T) were 27, 22, 16, 18, 19 and 11%, respectively. The DNA G+C content of strain ChimEc512(T) was 58.9 mol%. The major cellular fatty acid was C18 : 1?7c, characteristic of the genus Rhizobium . The polar lipid profile included phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol and phosphatidylcholine and moderate amounts of aminolipids, phospholipid and sulfoquinovosyl diacylglycerol. Although ChimEc512(T) was able to nodulate A. vulneraria, the nodC and nifH genes were not detected by PCR. The rhizobial strain was tolerant to high concentrations of heavy metals: up to 35 mM Zn and up to 0.5 mM Cd and its growth kinetics was not impacted by Zn. The results of DNA-DNA hybridizations and physiological tests allowed genotypic and phenotypic differentiation of strain ChimEc512(T) from species of the genus Rhizobium with validly published names. Strain ChimEc512(T), therefore, represents a novel species, for which the name Rhizobium metallidurans sp. nov. is proposed, with the type strain ChimEc512(T) (?=DSM 26575 = CIP 110550(T)). PMID:25701848

  4. The hyperaccumulator Sedum plumbizincicola harbors metal-resistant endophytic bacteria that improve its phytoextraction capacity in multi-metal contaminated soil.

    PubMed

    Ma, Ying; Oliveira, Rui S; Nai, Fengjiao; Rajkumar, Mani; Luo, Yongming; Rocha, Inês; Freitas, Helena

    2015-06-01

    Endophyte-assisted phytoremediation has recently been suggested as a successful approach for ecological restoration of metal contaminated soils, however little information is available on the influence of endophytic bacteria on the phytoextraction capacity of metal hyperaccumulating plants in multi-metal polluted soils. The aims of our study were to isolate and characterize metal-resistant and 1-aminocyclopropane-1-carboxylate (ACC) utilizing endophytic bacteria from tissues of the newly discovered Zn/Cd hyperaccumulator Sedum plumbizincicola and to examine if these endophytic bacterial strains could improve the efficiency of phytoextraction of multi-metal contaminated soils. Among a collection of 42 metal resistant bacterial strains isolated from the tissues of S. plumbizincicola grown on Pb/Zn mine tailings, five plant growth promoting endophytic bacterial strains (PGPE) were selected due to their ability to promote plant growth and to utilize ACC as the sole nitrogen source. The five isolates were identified as Bacillus pumilus E2S2, Bacillus sp. E1S2, Bacillus sp. E4S1, Achromobacter sp. E4L5 and Stenotrophomonas sp. E1L and subsequent testing revealed that they all exhibited traits associated with plant growth promotion, such as production of indole-3-acetic acid and siderophores and solubilization of phosphorus. These five strains showed high resistance to heavy metals (Cd, Zn and Pb) and various antibiotics. Further, inoculation of these ACC utilizing strains significantly increased the concentrations of water extractable Cd and Zn in soil. Moreover, a pot experiment was conducted to elucidate the effects of inoculating metal-resistant ACC utilizing strains on the growth of S. plumbizincicola and its uptake of Cd, Zn and Pb in multi-metal contaminated soils. Out of the five strains, B. pumilus E2S2 significantly increased root (146%) and shoot (17%) length, fresh (37%) and dry biomass (32%) of S. plumbizincicola as well as plant Cd uptake (43%), whereas Bacillus sp. E1S2 significantly enhanced the accumulation of Zn (18%) in plants compared with non-inoculated controls. The inoculated strains also showed high levels of colonization in rhizosphere and plant tissues. Results demonstrate the potential to improve phytoextraction of soils contaminated with multiple heavy metals by inoculating metal hyperaccumulating plants with their own selected functional endophytic bacterial strains. PMID:25796039

  5. "Towards practical cadmium phytoextraction with Thlaspi caerulescens"

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During 2005-2007, a series of field trials were conducted to investigate the potential of Thlapsi caerulescens ecotypes derived from southern France to phytoextract localized Cd/Zn contamination in Thailand. Soil treatments included pH variation and fertilization level. T. caerulescens ecotypes w...

  6. Identification and validation of heavy metal and radionuclide hyperaccumulating terrestrial plant species. Quarterly technical progress report, March 20, 1997--June 19, 1997

    SciTech Connect

    Kochian, L.

    1997-11-01

    This laboratory has been involved in a collaborative project focusing on a range of issues related to the phytoremediation of heavy metal-and radionuclide- contaminated soils. While much of the research has been fundamental in nature, involving physiological and molecular characterizations of the mechanisms of hyperaccumulation in plants, the laboratory is also investigating more practical issues related to phytoremediation. A central issue in this latter research has been the identification of amendments capable of increasing the bioavailability and subsequent phytoextraction of radionuclides. The results described here detail these efforts for uranium and Cs-137. A study was also conducted on a Cs-137 contaminated site at Brookhaven National Laboratory (BNL), which allowed application of the laboratory and greenhouse results to a field setting.

  7. Identification and validation of heavy metal and radionuclide hyperaccumulating terrestrial plant species, Quarterly technical progress report, December 20, 1995--March 20, 1995

    SciTech Connect

    Kochian, L.; Brady, D.; Last, M.; Ebbs, S.

    1995-12-01

    Although the period covered by this progress report began on December 20, 1994, which was the date that DOE approved the Interagency Agreement, the agreement was not approved by USDA until January 9, 1995 and the first scientists working on the project were not hired until February 1, 1995. The first goal of the research supported by the Interagency Agreement is to use hydroponic techniques to identify plant species and genotypes with potential for heavy metal hyperaccumulation for planting on a test site at Silverbow Creek and for radionuclide ({sup 90}Sr and {sup 137}Cs) accumulation on a test site at INEL, Idaho, later this year. The second goal of this research is to identify soil amendment procedures that will enhance the bioavailability of heavy metals and radionuclides in the soil without increasing the movement of the contaminants of concern (COC`s) into the groundwater. Our initial research covered in this report focuses on the first goal.

  8. Changes in metal availability, desorption kinetics and speciation in contaminated soils during repeated phytoextraction with the Zn/Cd hyperaccumulator Sedum plumbizincicola.

    PubMed

    Li, Zhu; Jia, Mingyun; Wu, Longhua; Christie, Peter; Luo, Yongming

    2016-02-01

    Phytoextraction is one of the most promising technologies for the remediation of metal contaminated soils. Changes in soil metal availability during phytoremediation have direct effects on removal efficiency and can also illustrate the interactive mechanisms between hyperaccumulators and metal contaminated soils. In the present study the changes in metal availability, desorption kinetics and speciation in four metal-contaminated soils during repeated phytoextraction by the zinc/cadmium hyperaccumulator Sedum plumbizincicola (S. plumbizincicola) over three years were investigated by chemical extraction and the DGT-induced fluxes in soils (DIFS) model. The available metal fractions (i.e. metal in the soil solution extracted by CaCl2 and by EDTA) decreased greatly by >84% after phytoextraction in acid soils and the deceases were dramatic at the initial stages of phytoextraction. However, the decreases in metal extractable by CaCl2 and EDTA in calcareous soils were not significant or quite low. Large decreases in metal desorption rate constants evaluated by DIFS were found in calcareous soils. Sequential extraction indicated that the acid-soluble metal fraction was easily removed by S. plumbizincicola from acid soils but not from calcareous soils. Reducible and oxidisable metal fractions showed discernible decreases in acid and calcareous soils, indicating that S. plumbizincicola can mobilize non-labile metal for uptake but the residual metal cannot be removed. The results indicate that phytoextraction significantly decreases metal availability by reducing metal pool sizes and/or desorption rates and that S. plumbizincicola plays an important role in the mobilization of less active metal fractions during repeated phytoextraction. PMID:26650084

  9. Stable isotope tracing: a powerful tool for selenium speciation and metabolic studies in non-hyperaccumulator plants (ryegrass Lolium perenne L.).

    PubMed

    Di Tullo, Pamela; Versini, Antoine; Bueno, Maïté; Le Hécho, Isabelle; Thiry, Yves; Biron, Philippe; Castrec-Rouelle, Maryse; Pannier, Florence

    2015-12-01

    Selenium is both essential and toxic for mammals; the range between the two roles is narrow and not only dose-dependent but also related to the chemical species present in foodstuff. Unraveling the metabolism of Se in plants as a function of Se source may thus lead to ways to increase efficiency of fertilization procedures in selenium deficient regions. In this study, stable-isotope tracing was applied for the first time in plants to simultaneously monitor the bio-incorporation of two inorganic Se species commonly used as foodstuff enrichment sources. Occurrence and speciation of Se coming from different Se sources were investigated in root and leaf extracts of ryegrass (Lolium perenne L.), which had been co-exposed to two labeled Se species ((77)SeIV and (82)SeVI). Although the plant absorbed similar amounts of Se when supplied in the form of selenite or selenate, the results evidenced marked differences in speciation and tissues allocation. Selenite was converted into organic forms incorporated mostly into high molecular weight compounds with limited translocation to leaves, whereas selenate was highly mobile being little assimilated into organic forms. Double-spike isotopic tracer methodology makes it possible to compare the metabolism of two species-specific Se sources simultaneously in a single experiment and to analyze Se behavior in not-hyperaccumulator plants, the ICP-MS sensitivity being improved by the use of enriched isotopes. PMID:26427506

  10. Transcriptome analysis of the key role of GAT2 gene in the hyper-accumulation of copper in the oyster Crassostrea angulata

    PubMed Central

    Shi, Bo; Huang, Zekun; Xiang, Xu; Huang, Miaoqin; Wang, Wen-Xiong; Ke, Caihuan

    2015-01-01

    One paradigm of oysters as the hyper-accumulators of many toxic metals is the inter-individual variation of metals, but the molecular mechanisms remain very elusive. A comprehensive analysis of the transcriptome of Crassostrea angulata was conducted to reveal the relationship between gene expression and differential Cu body burden in oysters. Gene ontology analysis for the differentially expressed genes showed that the neurotransmitter transporter might affect the oyster behavior, which in turn led to difference in Cu accumulation. The ATP-binding cassette transporters superfamily played an important role in the maintenance of cell Cu homeostasis, vitellogenin and apolipophorin transport, and elimination of excess Cu. Gill and mantle Cu concentrations were significantly reduced after silencing the GABA transporter 2 (GAT2) gene, but increased after the injection of GABA receptor antagonists, suggesting that the function of GABA transporter 2 gene was strongly related to Cu accumulation. These findings demonstrated that GABA transporter can control the action of transmitter GABA in the nervous system, thereby affecting the Cu accumulation in the gills and mantles. PMID:26648252

  11. Transcriptome analysis of the key role of GAT2 gene in the hyper-accumulation of copper in the oyster Crassostrea angulata.

    PubMed

    Shi, Bo; Huang, Zekun; Xiang, Xu; Huang, Miaoqin; Wang, Wen-Xiong; Ke, Caihuan

    2015-01-01

    One paradigm of oysters as the hyper-accumulators of many toxic metals is the inter-individual variation of metals, but the molecular mechanisms remain very elusive. A comprehensive analysis of the transcriptome of Crassostrea angulata was conducted to reveal the relationship between gene expression and differential Cu body burden in oysters. Gene ontology analysis for the differentially expressed genes showed that the neurotransmitter transporter might affect the oyster behavior, which in turn led to difference in Cu accumulation. The ATP-binding cassette transporters superfamily played an important role in the maintenance of cell Cu homeostasis, vitellogenin and apolipophorin transport, and elimination of excess Cu. Gill and mantle Cu concentrations were significantly reduced after silencing the GABA transporter 2 (GAT2) gene, but increased after the injection of GABA receptor antagonists, suggesting that the function of GABA transporter 2 gene was strongly related to Cu accumulation. These findings demonstrated that GABA transporter can control the action of transmitter GABA in the nervous system, thereby affecting the Cu accumulation in the gills and mantles. PMID:26648252

  12. Characterization of lead resistant endophytic Bacillus sp. MN3-4 and its potential for promoting lead accumulation in metal hyperaccumulator Alnus firma.

    PubMed

    Shin, Mi-Na; Shim, Jaehong; You, Youngnam; Myung, Hyun; Bang, Keuk-Soo; Cho, Min; Kamala-Kannan, Seralathan; Oh, Byung-Taek

    2012-01-15

    The aim of this study was to isolate and characterize endophytic bacteria from the roots of the metal hyperaccumulator plant Alnus firma. A total of 14 bacterial endophytes were isolated from root samples and assayed for tolerance to heavy metals. Isolate MN3-4 exhibited maximum bioremoval of Pb and was subsequently identified as Bacillus sp. based on 16S rRNA sequences. The pH and initial metal concentration highly influenced the Pb bioremoval rate. The growth of isolate MN3-4 was moderately altered in the presence of metals. Scanning electron microscopy, energy dispersive spectroscopy, biological-transmission electron microscopy, and Fourier transform infrared spectroscopy studies revealed that isolate MN3-4 had extracellularly sequestered the Pb molecules with little intracellular accumulation. Isolate MN3-4 did not harbor pbrA and pbrT genes. Moreover, isolate MN3-4 had the capacity to produce siderophores and indoleacetic acid. A root elongation assay demonstrated an increase (46.25%) in the root elongation of inoculated Brassica napus seedlings compared to that of the control plants. Obtained results pointed out that isolate MN3-4 could potentially reduce heavy metal phytotoxicity and increase Pb accumulation in A. firma plants. PMID:22133352

  13. CATION EXCHANGER1 Cosegregates with Cadmium Tolerance in the Metal Hyperaccumulator Arabidopsis halleri and Plays a Role in Limiting Oxidative Stress in Arabidopsis Spp.1[OPEN

    PubMed Central

    Baliardini, Cecilia; Meyer, Claire-Lise; Salis, Pietrino; Saumitou-Laprade, Pierre; Verbruggen, Nathalie

    2015-01-01

    Arabidopsis halleri is a model species for the study of plant adaptation to extreme metallic conditions. In this species, cadmium (Cd) tolerance seems to be constitutive, and the mechanisms underlying the trait are still poorly understood. A previous quantitative trait loci (QTL) analysis performed on A. halleri × Arabidopsis lyrata backcross population1 identified the metal-pump gene Heavy Metal ATPase4 as the major genetic determinant for Cd tolerance. However, although necessary, Heavy Metal ATPase4 alone is not sufficient for determining this trait. After fine mapping, a gene encoding a calcium2+/hydrogen+ antiporter, cation/hydrogen+ exchanger1 (CAX1), was identified as a candidate gene for the second QTL of Cd tolerance in A. halleri. Backcross population1 individuals displaying the A. halleri allele for the CAX1 locus exhibited significantly higher CAX1 expression levels compared with the ones with the A. lyrata allele, and a positive correlation between CAX1 expression and Cd tolerance was observed. Here, we show that this QTL is conditional and that it is only detectable at low external Ca concentration. CAX1 expression in both roots and shoots was higher in A. halleri than in the close Cd-sensitive relative species A. lyrata and Arabidopsis thaliana. Moreover, CAX1 loss of function in A. thaliana led to higher Cd sensitivity at low concentration of Ca, higher sensitivity to methylviologen, and stronger accumulation of reactive oxygen species after Cd treatment. Overall, this study identifies a unique genetic determinant of Cd tolerance in the metal hyperaccumulator A. halleri and offers a new twist for the function of CAX1 in plants. PMID:26162428

  14. Aluminium Uptake and Translocation in Al Hyperaccumulator Rumex obtusifolius Is Affected by Low-Molecular-Weight Organic Acids Content and Soil pH

    PubMed Central

    Vondrá?ková, Stanislava; Száková, Ji?ina; Drábek, Ond?ej; Tejnecký, Václav; Hejcman, Michal; Müllerová, Vladimíra; Tlustoš, Pavel

    2015-01-01

    Background and Aims High Al resistance of Rumex obtusifolius together with its ability to accumulate Al has never been studied in weakly acidic conditions (pH > 5.8) and is not sufficiently described in real soil conditions. The potential elucidation of the role of organic acids in plant can explain the Al tolerance mechanism. Methods We established a pot experiment with R. obtusifolius planted in slightly acidic and alkaline soils. For the manipulation of Al availability, both soils were untreated and treated by lime and superphosphate. We determined mobile Al concentrations in soils and concentrations of Al and organic acids in organs. Results Al availability correlated positively to the extraction of organic acids (citric acid < oxalic acid) in soils. Monovalent Al cations were the most abundant mobile Al forms with positive charge in soils. Liming and superphosphate application were ambiguous measures for changing Al mobility in soils. Elevated transport of total Al from belowground organs into leaves was recorded in both lime-treated soils and in superphosphate-treated alkaline soil as a result of sufficient amount of Ca available from soil solution as well as from superphosphate that can probably modify distribution of total Al in R. obtusifolius as a representative of “oxalate plants.” The highest concentrations of Al and organic acids were recorded in the leaves, followed by the stem and belowground organ infusions. Conclusions In alkaline soil, R. obtusifolius is an Al-hyperaccumulator with the highest concentrations of oxalate in leaves, of malate in stems, and of citrate in belowground organs. These organic acids form strong complexes with Al that can play a key role in internal Al tolerance but the used methods did not allow us to distinguish the proportion of total Al-organic complexes to the free organic acids. PMID:25880431

  15. Effect of thallium fractions in the soil and pollution origins on Tl uptake by hyperaccumulator plants: a key factor for the assessment of phytoextraction.

    PubMed

    Al-Najar, H; Kaschl, A; Schulz, R; Römheld, V

    2005-01-01

    Phytoremediation is often discussed as a means of extracting trace metals in excess in the soil, but to increase its efficiency a better understanding of the factors controlling plant uptake is required. The main objective of this study was to examine the effect of origin (anthropogenic vs. geogenic) and mobility of thallium (Tl) in the rhizosphere on Tl uptake. Two Tl-hyperaccumulating Brassicaceae species, kale (Brassica oleracea acephala L. cv. Winterbor F1) and candytuft (Iberis intermedia Guers.), were grown in a rhizobox system to investigate the dynamics of Tl in the rhizosphere soil. Four different soils were used. Two soils contained high Tl amounts due to anthropogenic sources (emissions from a cement plant and mining activities). High Tl content in the two other soils was due to a high rock content (geogenic origin). On completion of growth in the rhizoboxes, the depletion of Tl in seven different chemical fractions, determined by sequential extraction, was compared to the plant uptake. Most of the Tl taken up was derived from the so-called "easily accessible" fractions in both soils with geogenic Tl as well as in the soils polluted by mining activities. Due to the small amounts of easily accessible Tl in the geogenic soils, Tl uptake by Brassicaceae was low. On the other hand, for the air emission-polluted soil, a high depletion of Tl from "less accessible" fractions was observed in addition to depletion of the easily accessible fractions. Hence, the latter soil demonstrated the highest potential for effective soil decontamination by phytoextraction within an appropriate time frame. PMID:15943244

  16. Amino Acid Features of P1B-ATPase Heavy Metal Transporters Enabling Small Numbers of Organisms to Cope with Heavy Metal Pollution

    PubMed Central

    Ashrafi, E.; Alemzadeh, A.; Ebrahimi, M.; Ebrahimie, E.; Dadkhodaei, N.; Ebrahimi, M.

    2011-01-01

    Phytoremediation refers to the use of plants for extraction and detoxification of pollutants, providing a new and powerful weapon against a polluted environment. In some plants, such as Thlaspi spp, heavy metal ATPases are involved in overall metal ion homeostasis and hyperaccumulation. P1B-ATPases pump a wide range of cations, especially heavy metals, across membranes against their electrochemical gradients. Determination of the protein characteristics of P1B-ATPases in hyperaccumulator plants provides a new opportuntity for engineering of phytoremediating plants. In this study, using diverse weighting and modeling approaches, 2644 protein characteristics of primary, secondary, and tertiary structures of P1B-ATPases in hyperaccumulator and nonhyperaccumulator plants were extracted and compared to identify differences between proteins in hyperaccumulator and nonhyperaccumulator pumps. Although the protein characteristics were variable in their weighting, tree and rule induction models; glycine count, frequency of glutamine-valine, and valine-phenylalanine count were the most important attributes highlighted by 10, five, and four models, respectively. In addition, a precise model was built to discriminate P1B-ATPases in different organisms based on their structural protein features. Moreover, reliable models for prediction of the hyperaccumulating activity of unknown P1B-ATPase pumps were developed. Uncovering important structural features of hyperaccumulator pumps in this study has provided the knowledge required for future modification and engineering of these pumps by techniques such as site-directed mutagenesis. PMID:21573033

  17. Inoculation with endophytic Bacillus megaterium 1Y31 increases Mn accumulation and induces the growth and energy metabolism-related differentially-expressed proteome in Mn hyperaccumulator hybrid pennisetum.

    PubMed

    Zhang, Wen-Hui; He, Lin-Yan; Wang, Qi; Sheng, Xia-Fang

    2015-12-30

    In this study, a hydroponic culture experiment was conducted in a greenhouse to investigate the molecular and microbial mechanisms involved in the endophytic Bacillus megaterium 1Y31-enhanced Mn tolerance and accumulation in Mn hyperaccumulator hybrid pennisetum. Strain 1Y31 significantly increased the dry weights (ranging from 28% to 94%) and total Mn uptake (ranging from 23% to 112%) of hybrid pennisetum treated with 0, 2, and 10mM Mn compared to the control. Total 98 leaf differentially expressed proteins were identified between the live and dead bacterial inoculated hybrid pennisetum. The major leaf differentially expressed proteins were involved in energy generation, photosynthesis, response to stimulus, metabolisms, and unknown function. Furthermore, most of the energy generation and photosynthesis-related proteins were up-regulated, whereas most of the response to stimulus and metabolism-related proteins were down-regulated under Mn stress. Notably, the proportion of indole-3-acetic acid (IAA)-producing endophytic bacteria was significantly higher in the bacterial inoculated plants under Mn stress. The results suggested that strain 1Y31 increased the growth and Mn uptake of hybrid pennisetum through increasing the efficiency of photosynthesis and energy metabolism as well as the proportion of plant growth-promoting endophytic bacteria in the plants. PMID:26241871

  18. Expression of HMA4 cDNAs of the zinc hyperaccumulator Noccaea caerulescens from endogenous NcHMA4 promoters does not complement the zinc-deficiency phenotype of the Arabidopsis thaliana hma2hma4 double mutant.

    PubMed

    Iqbal, Mazhar; Nawaz, Ismat; Hassan, Zeshan; Hakvoort, Henk W J; Bliek, Mattijs; Aarts, Mark G M; Schat, Henk

    2013-01-01

    Noccaea caerulescens (Nc) exhibits a very high constitutive expression of the heavy metal transporting ATPase, HMA4, as compared to the non-hyperaccumulator Arabidopsis thaliana (At), due to copy number expansion and altered cis-regulation. We screened a BAC library for HMA4 and found that HMA4 is triplicated in the genome of a N. caerulescens accession from a former Zn mine near La Calamine (LC), Belgium. We amplified multiple HMA4 promoter sequences from three calamine N. caerulescens accessions, and expressed AtHMA4 and different NcHMA4 cDNAs under At and Nc HMA4 promoters in the A. thaliana (Col) hma2hma4 double mutant. Transgenic lines expressing HMA4 under the At promoter were always fully complemented for root-to-shoot Zn translocation and developed normally at a 2-?M Zn supply, whereas the lines expressing HMA4 under Nc promoters usually showed only slightly enhanced root to shoot Zn translocation rates in comparison with the double mutant, probably owing to ectopic expression in the roots, respectively. When expression of the Zn deficiency responsive marker gene ZIP4 was tested, the transgenic lines expressing AtHMA4 under an NcHMA4-1-LC promoter showed on average a 7-fold higher expression in the leaves, in comparison with the double hma2hma4 mutant, showing that this construct aggravated, rather than alleviated the severity of foliar Zn deficiency in the mutant, possible owing to expression in the leaf mesophyll. PMID:24187545

  19. Expression of HMA4 cDNAs of the zinc hyperaccumulator Noccaea caerulescens from endogenous NcHMA4 promoters does not complement the zinc-deficiency phenotype of the Arabidopsis thaliana hma2hma4 double mutant

    PubMed Central

    Iqbal, Mazhar; Nawaz, Ismat; Hassan, Zeshan; Hakvoort, Henk W. J.; Bliek, Mattijs; Aarts, Mark G.M.; Schat, Henk

    2013-01-01

    Noccaea caerulescens (Nc) exhibits a very high constitutive expression of the heavy metal transporting ATPase, HMA4, as compared to the non-hyperaccumulator Arabidopsis thaliana (At), due to copy number expansion and altered cis-regulation. We screened a BAC library for HMA4 and found that HMA4 is triplicated in the genome of a N. caerulescens accession from a former Zn mine near La Calamine (LC), Belgium. We amplified multiple HMA4 promoter sequences from three calamine N. caerulescens accessions, and expressed AtHMA4 and different NcHMA4 cDNAs under At and Nc HMA4 promoters in the A. thaliana (Col) hma2hma4 double mutant. Transgenic lines expressing HMA4 under the At promoter were always fully complemented for root-to-shoot Zn translocation and developed normally at a 2-?M Zn supply, whereas the lines expressing HMA4 under Nc promoters usually showed only slightly enhanced root to shoot Zn translocation rates in comparison with the double mutant, probably owing to ectopic expression in the roots, respectively. When expression of the Zn deficiency responsive marker gene ZIP4 was tested, the transgenic lines expressing AtHMA4 under an NcHMA4-1-LC promoter showed on average a 7-fold higher expression in the leaves, in comparison with the double hma2hma4 mutant, showing that this construct aggravated, rather than alleviated the severity of foliar Zn deficiency in the mutant, possible owing to expression in the leaf mesophyll. PMID:24187545

  20. Identification and validation of heavy metal and radionuclide accumulating terrestrial plant species. Quarterly technical progress report, June 21, 1995--September 20, 1995

    SciTech Connect

    Kochian, L.

    1995-12-31

    This quarterly report describes experiments on uptake of a variety of heavy metals by plants. Titles of report sections are (1) Alleviation of heavy-metal induced micronutrient deficiency through foliar fertilization, (2) Second screen for Zn, Cu, and Cd accumulation, (3) Characterization of the root Zn hyperaccumulation by Thlaspi caerulescens, (4) Comparison of commercial Brassica accessions obtained from the Iowa seed bank, (5) Second screening experiment for the accumulation of Cs and Sr by plants, (6) Effect of Ca on Cs and Sr accumulation by selected dicot species, and (7) Preliminary investigations into the forms of uranium taken up by plants.

  1. Adaptation of Biscutella laevigata L, a metal hyperaccumulator, to growth on a zinc-lead waste heap in southern Poland. I: Differences between waste-heap and mountain populations.

    PubMed

    Wierzbicka, M; Pielichowska, M

    2004-03-01

    Biscutella laevigata is an herbal member of the Brasicacae family and a typical mountain species. It has recently been identified as a hyperaccumulator of lead, cadmium and thallium. Its northern reach runs through Poland, where it is found only in the west Tatra Mountains and on calamine waste heaps in the vicinity of Olkusz (Cracow--Silesian Highland). The peculiar distribution of this species in Poland prompted us to undertake studies to identify the traits that allow this typically mountain species to grow so robustly on industrial waste heaps near zinc and lead smelters in the vicinity of Olkusz. Populations of B. laevigata from waste heaps and the Tatra Mountains were compared both under field (natural) conditions and during cultivation of successive generations under laboratory conditions. It was found that the mountain and waste-heap populations of B. laevigata differed significantly. The plants in the mountain population had thicker leaves covered with cutin and a small number of hairs, whereas the plants from the waste-heap population had thin leaves covered with numerous hairs. The difference in leaf thickness between the two populations (0.15 mm on average) was due to increased dimensions of palisade mesophyl cells whereas the number of cells in their leaves remained similar. These traits were hereditary. This indicates that two geographically distant populations of plants followed two different evolutionary paths to adapt to xerothermic conditions. Moreover, it was shown that the waste-heap population of B. laevigata is more tolerant to heavy metals (lead, zinc and cadmium). In the presence of both zinc and lead, growth of the waste-heap plants was stimulated, while under the same conditions, growth of the mountain population was inhibited lower than 50%. This adaptation facilitates the growth of this population on industrial waste heaps. Our studies show that B. laevigata is a valuable species very well-suited for use in the recultivation of areas containing high levels of heavy metals--the waste-heap population of this species is particularly valuable. PMID:14675845

  2. Phytoremediation of heavy metal polluted soils and water: Progresses and perspectives*

    PubMed Central

    Lone, Mohammad Iqbal; He, Zhen-li; Stoffella, Peter J.; Yang, Xiao-e

    2008-01-01

    Environmental pollution affects the quality of pedosphere, hydrosphere, atmosphere, lithosphere and biosphere. Great efforts have been made in the last two decades to reduce pollution sources and remedy the polluted soil and water resources. Phytoremediation, being more cost-effective and fewer side effects than physical and chemical approaches, has gained increasing popularity in both academic and practical circles. More than 400 plant species have been identified to have potential for soil and water remediation. Among them, Thlaspi, Brassica, Sedum alfredii H., and Arabidopsis species have been mostly studied. It is also expected that recent advances in biotechnology will play a promising role in the development of new hyperaccumulators by transferring metal hyperaccumulating genes from low biomass wild species to the higher biomass producing cultivated species in the times to come. This paper attempted to provide a brief review on recent progresses in research and practical applications of phytoremediation for soil and water resources. PMID:18357623

  3. Accumulation and hyperaccumulation of copper in plants

    NASA Astrophysics Data System (ADS)

    Adam, V.; Trnkova, L.; Huska, D.; Babula, P.; Kizek, R.

    2009-04-01

    Copper is natural component of our environment. Flow of copper(II) ions in the environment depends on solubility of compounds containing this metal. Mobile ion coming from soil and rocks due to volcanic activity, rains and others are then distributed to water. Bio-availability of copper is substantially lower than its concentration in the aquatic environment. Copper present in the water reacts with other compounds and creates a complex, not available for organisms. The availability of copper varies depending on the environment, but moving around within the range from 5 to 25 % of total copper. Thus copper is stored in the sediments and the rest is transported to the seas and oceans. It is common knowledge that copper is essential element for most living organisms. For this reason this element is actively accumulated in the tissues. The total quantity of copper in soil ranges from 2 to 250 mg / kg, the average concentration is 30 mg / kg. Certain activities related to agriculture (the use of fungicides), possibly with the metallurgical industry and mining, tend to increase the total quantity of copper in the soil. This amount of copper in the soil is a problem particularly for agricultural production of food. The lack of copper causes a decrease in revenue and reduction in quality of production. In Europe, shows the low level of copper in total 18 million hectares of farmland. To remedy this adverse situation is the increasing use of copper fertilizers in agricultural soils. It is known that copper compounds are used in plant protection against various illnesses and pests. Mining of minerals is for the development of human society a key economic activity. An important site where the copper is mined in the Slovakia is nearby Smolníka. Due to long time mining in his area (more than 700 years) there are places with extremely high concentrations of various metals including copper. Besides copper, there are also detected iron, zinc and arsenic. Various plant species have adapted on such stress. The aim of this study is to investigate the behaviour of copper in plants and to assess its potential effect on the surrounding environment. To detect copper in biological samples electrochemical methods were employed particularly differential pulse voltammetry (DPV). Copper gave signals at 0.02 V measured by DPV. The obtained calibration dependence was linear (R2 = 0.995). Further, this method was utilized for determination of copper in real soil samples obtained from previously mentioned heavy-metal-polluted mining area. The content varied within range from tens to hundreds of mg of copper per kg of the soil. Moreover, we focused on investigation of copper influence on seedlings of Norway spruce. The seedlings were treated with copper (0, 0.1, 10 and 100 mM) for four weeks. We observed anatomical-morphological changes and other biochemical parameters in plants. We determined that seedlings synthesized more than 48 % protective thiols (glutathione and phytochelatins) compared to control ones. We investigated copper distribution in plant tissues by diphenylcarbazide staining. We found out that copper is highly accumulated in parenchymal stalk cells. In needles, change in auto-fluorescence of parenchymal cells of mesoderm similarly to endodermis cells. Besides, we analyzed samples of plants from the polluted area (spruce, pin, birch). The data obtained well correlated with previously mentioned. Acknowledgement The work on this experiment was supported by grant: INCHEMBIOL MSM0021622412.

  4. Rhizosphere Characteristics of the Arsenic Hyperaccumulator Pteris

    E-print Network

    Ma, Lena

    lowered drinking water standards (6, 7), as it has been shown that inorganic As is toxic at even lower University, Lancaster LA1 4YQ, U.K., Institute of Chemistry, BOKUsUniversity of Natural Resources and Applied Vienna, Austria, and Soil and Water Science Department, University of Florida, Gainsville, Florida 32611

  5. Genetic and Molecular Dissection of Arsenic Hyperaccumulation

    SciTech Connect

    Banks, Jo Ann

    2005-06-01

    We have constructed cDNA libraries from RNA isolated from arsenic treated gametophytes of the fern Pteris vittata. This library was made in a manner that allows each cDNA clone to be expressed in yeast. We have introduced this library into yeast cells, both wild type and arsensic sensitive mutants, and selected transformed yeast colonies with increased arsenic tolerance compared to the parental strains. From these screens we have identified putative homologs of the yeast ACR2 and ACR3 genes from Pteris vittata and, for the past year, have focused on characterizing the function of the ACR2 gene. In yeast, ACR2 is an arsenate reductase that is essential for arsenate tolerance. We refer to the Pteris vittata ACR2 gene as PvACR2. The deduced amino acid sequence of PvACR2 is highly similar to the yeast ACR2 and other related phosphatases.

  6. Extraction of pennycress (Thlaspi arvense L.) seed oil by full pressing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress is currently being developed as an oilseed crop for biofuel production. Pennycress seeds harvested from a field near Peoria, IL, provided our first opportunity to conduct an oil extraction study on a pilot scale. The goals of this study were to determine the effects of seed moisture and c...

  7. Blackwell Publishing Ltd Hyperaccumulator Alyssum murale relies on a different

    E-print Network

    and taxpayers. Anthropogenic metal inputs include spoil from metal mining operations, fallout from refinery emissions, waste disposal, electroplating, combustion of fossil fuels, and agricultural application

  8. IN VIVO SYNCHROTRON INVESTIGATION OF THALLIUM HYPERACCUMULATION - I

    EPA Science Inventory

    Thallium (TI) is a metal of great toxicological concern and its prevalence in the natural environment has steadily increased as a result of manufacturing and combustion practices. Due to its low natural abundance and the increasing demand, TI recovery and reuse could be a profita...

  9. Antimony uptake, efflux and speciation in arsenic hyperaccumulator Pteris vittata

    E-print Network

    Ma, Lena

    of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 210046, China c of Sb has drastically increased due to its use in car brake linings and fire retardants (Maher, 2009

  10. Molecular mechanisms of selenium tolerance and hyperaccumulation in Stanleya pinnata

    E-print Network

    Freeman, John L.

    2010-01-01

    ROS formation and oxidative stress in plants (Gomes-Junior,oxidative stress in coffee cell suspension cultures. Func Plantstress resistance and are regulated by the relative oxidative status of the plant.

  11. Growth and cadmium uptake of Swiss chard, Thlaspi caerulescens and corn in pH adjusted biosolids amended soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Before regulations were established, some biosolids applications added higher Cd levels than presently permitted. Cadmium phytoextraction from such soils would alleviate constraints on land use. Unamended farm soil, and biosolids amended farm soil and mine soil were obtained from Fulton County, Il...

  12. Variation in HMA4 gene copy number and expression among Noccaea caerulescens populations presenting different levels of Cd tolerance and accumulation.

    PubMed

    Craciun, Adrian R; Meyer, Claire-Lise; Chen, Jiugeng; Roosens, Nancy; De Groodt, Ruth; Hilson, Pierre; Verbruggen, Nathalie

    2012-06-01

    There is huge variability among populations of the hyperaccumulator Noccaea caerulescens (formerly Thlaspi caerulescens) in their capacity to tolerate and accumulate cadmium. To gain new insights into the mechanisms underlying this variability, we estimated cadmium fluxes and further characterized the N. caerulescens heavy metal ATPase 4 (NcHMA4) gene in three populations (two calamine, Saint-Félix-de-Pallières, France and Prayon, Belgium; one serpentine, Puente Basadre, Spain) presenting contrasting levels of tolerance and accumulation. Cadmium uptake and translocation varied among populations in the same way as accumulation; the population with the highest cadmium concentration in shoots (Saint Félix-de-Pallières) presented the highest capacity for uptake and translocation. We demonstrated that the four NcHMA4 copies identified in a previous study are not fixed at the species level, and that the copy truncated in the C-terminal part encodes a functional protein. NcHMA4 expression and gene copy number was lower in the serpentine population, which was the least efficient in cadmium translocation compared to the calamine populations. NcHMA4 expression was associated with the vascular tissue in all organs, with a maximum at the crown. Overall, our results indicate that differences in cadmium translocation ability of the studied populations appear to be controlled, at least partially, by NcHMA4, while the overexpression of NcHMA4 in the two calamine populations may result from convergent evolution. PMID:22581842

  13. Thermal treatment of metal-enriched biomass produced from heavy metal phytoextraction.

    PubMed

    Keller, Catherine; Ludwig, Christian; Davoli, Frédéric; Wochele, Jörg

    2005-05-01

    Phytoextraction is an environmentally sound method for cleaning up sites that are contaminated with toxic heavy metals. However, the method has been questioned because it produces a biomass-rich secondary waste containing the extracted metals. Therefore, further treatment of this biomass is necessary. In this study, we investigated whether thermal treatment could be a feasible option for evaporatively separating metals from the plant residues. We used a laboratory scale reactor designed to simulate the volatilization behavior of heavy metals in a grate furnace. The evaporation of alkali and heavy metals from plant samples was investigated online, using a thermo-desorption spectrometer (TDS). Experiments were performed in the temperature range of 25-950 degrees C with leaves of the Cd and Zn hyperaccumulator Thlaspi caerulescens and of the high biomass plant Salix viminalis (willow), both grown on contaminated soils. Gasification (i.e., pyrolysis), which occurs under reducing conditions, was a better method than incineration under oxidizing conditions to increase volatilization and, hence subsequently recovery, of Cd and Zn from plants. It would also allow the recycling of the bottom ash as fertilizer. Thus, our investigations confirmed that incineration (or co-incineration) is a viable option for the treatment of the heavy metal-enriched plants. PMID:15926590

  14. Copper localization, elemental content, and thallus colour in the copper hyperaccumulator lichen Lecanora sierra from California

    USGS Publications Warehouse

    Purvis, O.W.; Bennett, J.P.; Spratt, J.

    2011-01-01

    An unusual dark blue-green lichen, Lecanora sierrae, was discovered over 30 years ago by Czehura near copper mines in the Lights Creek District, Plumas County, Northern California. Using atomic absorption spectroscopy, Czehura found that dark green lichen samples from Warren Canyon contained 4% Cu in ash and suggested that its colour was due to copper accumulation in the cortex. The present study addressed the hypothesis that the green colour in similar material we sampled from Warren Canyon in 2008, is caused by copper localization in the thallus. Optical microscopy and electron microprobe analysis of specimens of L. sierrae confirmed that copper localization took place in the cortex. Elemental analyses of L. sierrae and three other species from the same localities showed high enrichments of copper and selenium, suggesting that copper selenates or selenites might occur in these lichens and be responsible for the unusual colour.

  15. Copper localization, elemental content, and thallus colour in the copper hyperaccumulator lichen Lecanora sierrae from California

    USGS Publications Warehouse

    Purvis, O.W.; Bennett, J.P.; Spratt, J.

    2011-01-01

    An unusual dark blue-green lichen, Lecanora sierrae, was discovered over 30 years ago by Czehura near copper mines in the Lights Creek District, Plumas County, Northern California. Using atomic absorption spectroscopy, Czehura found that dark green lichen samples from Warren Canyon contained 4% Cu in ash and suggested that its colour was due to copper accumulation in the cortex. The present study addressed the hypothesis that the green colour in similar material we sampled from Warren Canyon in 2008, is caused by copper localization in the thallus. Optical microscopy and electron microprobe analysis of specimens of L. sierrae confirmed that copper localization took place in the cortex. Elemental analyses of L. sierrae and three other species from the same localities showed high enrichments of copper and selenium, suggesting that copper selenates or selenites might occur in these lichens and be responsible for the unusual colour. Copyright ?? 2011 British Lichen Society.

  16. Effects of Plant Age on Arsenic Hyperaccumulation by Pteris vittata L.

    E-print Network

    Ma, Lena

    and iron accumulation in the roots of older plants may have affected the plant's efficiency age. It is known that during the sigmoidal phase of a plant growth cycle, dry matter and nutrient with plant age, which influence biomass production, and nutrient and contaminant accumulation. For instance

  17. CHARACTERIZATION OF ARSENIC RESISTANT BACTERIAL COMMUNITIES IN THE RHIZOSPHERE OF AN ARSENIC HYPERACCUMULATOR Pteris vittata L.

    E-print Network

    Ma, Lena

    CHARACTERIZATION OF ARSENIC RESISTANT BACTERIAL COMMUNITIES IN THE RHIZOSPHERE OF AN ARSENIC..................................................................................................................11 1.1 Environmental Sources of Arsenic..................................................................................11 1.1.1 Arsenic in the Environment

  18. Mechanisms of nickel uptake, and hyperaccumulation by plants and implications to soil remediation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil contamination by heavy metals like Ni was originally restricted to metalliferous soils but in recent years it has become a general problem due to the increasingly frequent anthropogenic activities. Because of the characteristics of cost-effectiveness, environmental friendliness, and fewer side...

  19. Bioenergy crops grown for hyperaccumulation of phosphorous in the Delmarva Peninsula and their biofuels potential.

    PubMed

    Boateng, Akwasi A; Serapiglia, Michelle J; Mullen, Charles A; Dien, Bruce S; Hashem, Fawzy M; Dadson, Robert B

    2015-03-01

    Herbaceous bioenergy crops, including sorghum, switchgrass, and miscanthus, were evaluated for their potential as phytoremediators for the uptake of phosphorus in the Delmarva Peninsula and their subsequent conversion to biofuel intermediates (bio-oil) by fast pyrolysis using pyrolysis-gas chromatography/mass spectroscopy. Four cultivars of sorghum, five cultivars of switchgrass and one miscanthus (Miscanthus × giganteus) were grown in soils with two different levels of poultry manure (PM) applications. Little variation was seen in phosphorus uptake in the two different soils indicating that the levels of available phosphorus in the soil already saturated the uptake ability of the plants. However, all plants regardless of trial took up more phosphorus than that measured for the non- PM treated control. Sorghum accumulated greater levels of nutrients including phosphorus and potassium compared to switchgrass and miscanthus. The levels of these nutrients in the biomass did not have an effect on carbohydrate contents. However, the potential yield and composition of bio-oil from fast pyrolysis were affected by both agronomics and differences in mineral concentrations. PMID:25460422

  20. Chromate and phosphate inhibited each other's uptake and translocation in arsenic hyperaccumulator Pteris vittata L.

    E-print Network

    Ma, Lena

    in plant growth and changes in plant morphology (Lopez-Bucio et al., 2014). Cr occurs in the environment the environment. Phosphorus is an essential macronutrient required for plant growth, often making up 0.2e0 Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu

  1. MOLECULAR DISSECTION OF THE CELLULAR MECHANISMS INVOLVED IN NICKEL HYPERACCUMULATION IN PLANTS

    EPA Science Inventory

    Phytoremediation, the use of plants for environmental cleanup of pollutants, including toxic metals, holds the potential to allow the economic restoration of heavy metal and radionuclide contaminated sites.A number of terrestrial plants are known to naturally accumulate high le...

  2. CORRECTING MICRONUTRIENT DEFICIENCY USING METAL HYPERACCUMULATORS: ALYSSUM BIOMASS AS A NATURAL PRODUCT FOR NICKEL DEFICIENCY CORRECTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The existence of nickel (Ni) deficiency in certain horticultural crops merits development of fertilizer products suitable for specific niche uses and for correcting or preventing deficiency problems before marketability and yields are affected. The efficacy of satisfying plant nutritional needs for ...

  3. Antioxidative responses to arsenic in the arsenic-hyperaccumulator Chinese brake fern (Pteris vittata L.)

    E-print Network

    Ma, Lena

    and Huang, 2001; Karenlampi et al., 2000). Plants living under oxidative stress of heavy metals exhibit). #12;scavenge toxic free radicals to protect themselves from the oxidant stress including heavy metals of Florida, Gainesville, FL 32611, USA b Department of Plant Pathology, North Carolina State University

  4. Are plants growing at abandoned mine sites suitable for phytoremediation of contaminated soils?

    NASA Astrophysics Data System (ADS)

    Bini, Claudio; Buffa, Gabriella; Fontana, Silvia; Wahsha, Mohammad

    2013-04-01

    Plants growing on abandoned mine sites are of particular interest in the perspective to remediate contaminated soils by phytoremediation, a low cost and environmental friendly technique which uses metal-accumulator plants to clean up moderately contaminated areas. The choice of plants is a crucial aspect for the practical use of this technique, given the ability to accumulate metals in their tissues, being genetically tolerant to high metal concentrations. Up today, more than 400 native plants that hyperaccumulate metals are reported, Brassicaceae being the family with the largest number of hyperaccumulator species. For example, Alyssum bertoloni is well known as Ni accumulator, as well as Thlaspi caerulescens for Zn and Brassica napus for Pb. However, metal hyperaccumulation is not a common phenomenon in terrestrial higher plants, and many of the European hyperaccumulator plants are of small biomass, and have a slow growth rate. Therefore, there is an urgent need for surveying and screening of plants with ability to accumulate metals in their tissues and a relatively high biomass. In recent years, a survey of soils and plants growing on contaminated areas at several abandoned sulphide mines in Italy was carried out by working groups of the Universities of Florence, Siena, Cagliari, Bologna, Udine and Venice, in order to evaluate the ability of these plants to colonize mine waste and to accumulate metals, in the perspective of an ecological restoration of contaminated sites. We investigated the heavy metal concentration of the waste material, and the soils developed from, in order to determine the extent of heavy metal dispersion, and the uptake by plants, and deserved attention to wild plants growing at that sites, to find out new metal-tolerant species to utilize in soil remediation. Current results of these investigations, with particular emphasis on the Tuscan areas, are reported here. All the studied profiles are strongly enriched in metals; their concentration, however, depends on the distance from mine areas, as indicated in the following table: Sample Metal Mean (ppm) Range (ppm) Waste soils ENTISOLS Cu 3527 62-10200 Pb 301 30-830 Zn 798 110-1950 Proximal soils INCEPTISOLS Cu 1081 16-3400 Pb 623 45-1900 Zn 792 420-1300 Distal soils ALFISOLS Cu 193 80-340 Pb 267 160-430 Zn 672 410-890 Wild plants (e.g. fescue, plantain, common reed, mint, marigold, dandelion, moon plant, rock-rose, willow) were found to be metal-tolerant and to accumulate high levels of As, Cd, Cr, Cu, Pb, Zn in their tissues (both roots and aerial parts), although at different extent in response to their metabolic activity, physiology, and to soil and environmental characteristics. In conclusion, the evaluation of metal uptake by plants, combined with geobotanical observations, is an useful tool to find tolerant plant populations to be used in revegetation programs aimed at reducing the environmental impact of contaminated areas.

  5. Brassicaceae (Mustard family) Field pennycress

    E-print Network

    Brassicaceae (Mustard family) Field pennycress Thlaspi arvense L. Life cycle Erect winter or summer. Back to identifying Christmas tree weeds. #12;Brassicaceae (Mustard family) Field pennycress continued

  6. Arsenic uptake, arsenite efflux and plant growth in hyperaccumulator Pteris vittata: Role of arsenic-resistant bacteria

    E-print Network

    Ma, Lena

    of arsenic-resistant bacteria Yong-He Han a , Jing-Wei Fu a , Yanshan Chen a , Bala Rathinasabapathi b , Lena-resistant endophytic and rhizo- spheric bacteria were investigated. All bacteria were AsV reducers except one strong AsIII oxidizer. Pteris vittata (PV) sporophytes took up more AsV than AsIII. Bacteria significantly

  7. This paper reviews progress in phytoextraction of soil elements and illustrates the key role of hyperaccumulator plant species

    E-print Network

    Sparks, Donald L.

    soils contaminated by mine wastes and smelter emissions with 100-fold more soil Zn than Cd. Although of Cd. Production of element-enriched biomass with value as ore or fertilizer or improved food (SeTechnologies Rufus L. Chaney* USDA-ARS J. Scott Angle University of Georgia C. Leigh Broadhurst USDA-ARS Carinne A

  8. Intraspecific variability of cadmium tolerance and accumulation, and cadmium-induced cell wall modifications in the metal hyperaccumulator Arabidopsis halleri

    PubMed Central

    Meyer, Claire-Lise; Juraniec, Michal; Huguet, Stéphanie; Chaves-Rodriguez, Elena; Salis, Pietro; Isaure, Marie-Pierre; Goormaghtigh, Erik; Verbruggen, Nathalie

    2015-01-01

    Certain molecular mechanisms of Cd tolerance and accumulation have been identified in the model species Arabidopsis halleri, while intraspecific variability of these traits and the mechanisms of shoot detoxification were little addressed. The Cd tolerance and accumulation of metallicolous and non-metallicolous A. halleri populations from different genetic units were tested in controlled conditions. In addition, changes in shoot cell wall composition were investigated using Fourier transform infrared spectroscopy. Indeed, recent works on A. halleri suggest Cd sequestration both inside cells and in the cell wall/apoplast. All A. halleri populations tested were hypertolerant to Cd, and the metallicolous populations were on average the most tolerant. Accumulation was highly variable between and within populations, and populations that were non-accumulators of Cd were identified. The effect of Cd on the cell wall composition was quite similar in the sensitive species A. lyrata and in A. halleri individuals; the pectin/polysaccharide content of cell walls seems to increase after Cd treatment. Nevertheless, the changes induced by Cd were more pronounced in the less tolerant individuals, leading to a correlation between the level of tolerance and the extent of modifications. This work demonstrated that Cd tolerance and accumulation are highly variable traits in A. halleri, suggesting adaptation at the local scale and involvement of various molecular mechanisms. While in non-metallicolous populations drastic modifications of the cell wall occur due to higher Cd toxicity and/or Cd immobilization in this compartment, the increased tolerance of metallicolous populations probably involves other mechanisms such as vacuolar sequestration. PMID:25873677

  9. Biochemical Characterization of Plant Small CTD Phosphatases and Application of CTD Phosphatase Mutant in Hyperaccumulation of Flavonoids in Arabidopsis 

    E-print Network

    Feng, Yue

    2011-10-21

    in turn regulate the activity of SNF1-related protein kinases 2 (SnRK2) family proteins (Fujii et al., 2009; Vlad et al., 2009). 8 Transcription activation of ABA-responsive genes is mediated by bZIP type transcription factors ABFs, such as ABI5...

  10. Effects of compost and phosphate amendments on arsenic mobility in soils and arsenic uptake by the hyperaccumulator,

    E-print Network

    Ma, Lena

    Effects of compost and phosphate amendments on arsenic mobility in soils and arsenic uptake of Florida, Gainesville, FL 32611, USA Received 21 February 2003; accepted 26 May 2003 ``Capsule'': Phosphate or in As spiked contaminated (ASC) soil. Soils were treated with phosphate rock, municipal solid waste

  11. Rhizosphere Microbial Community Composition Affects Cadmium and Zinc Uptake by the Metal-Hyperaccumulating Plant Arabidopsis halleri

    PubMed Central

    Muehe, E. Marie; Weigold, Pascal; Adaktylou, Irini J.; Planer-Friedrich, Britta; Kraemer, Ute; Kappler, Andreas

    2015-01-01

    The remediation of metal-contaminated soils by phytoextraction depends on plant growth and plant metal accessibility. Soil microorganisms can affect the accumulation of metals by plants either by directly or indirectly stimulating plant growth and activity or by (im)mobilizing and/or complexing metals. Understanding the intricate interplay of metal-accumulating plants with their rhizosphere microbiome is an important step toward the application and optimization of phytoremediation. We compared the effects of a “native” and a strongly disturbed (gamma-irradiated) soil microbial communities on cadmium and zinc accumulation by the plant Arabidopsis halleri in soil microcosm experiments. A. halleri accumulated 100% more cadmium and 15% more zinc when grown on the untreated than on the gamma-irradiated soil. Gamma irradiation affected neither plant growth nor the 1 M HCl-extractable metal content of the soil. However, it strongly altered the soil microbial community composition and overall cell numbers. Pyrosequencing of 16S rRNA gene amplicons of DNA extracted from rhizosphere samples of A. halleri identified microbial taxa (Lysobacter, Streptomyces, Agromyces, Nitrospira, “Candidatus Chloracidobacterium”) of higher relative sequence abundance in the rhizospheres of A. halleri plants grown on untreated than on gamma-irradiated soil, leading to hypotheses on their potential effect on plant metal uptake. However, further experimental evidence is required, and wherefore we discuss different mechanisms of interaction of A. halleri with its rhizosphere microbiome that might have directly or indirectly affected plant metal accumulation. Deciphering the complex interactions between A. halleri and individual microbial taxa will help to further develop soil metal phytoextraction as an efficient and sustainable remediation strategy. PMID:25595759

  12. Rhizosphere microbial community composition affects cadmium and zinc uptake by the metal-hyperaccumulating plant Arabidopsis halleri.

    PubMed

    Muehe, E Marie; Weigold, Pascal; Adaktylou, Irini J; Planer-Friedrich, Britta; Kraemer, Ute; Kappler, Andreas; Behrens, Sebastian

    2015-03-01

    The remediation of metal-contaminated soils by phytoextraction depends on plant growth and plant metal accessibility. Soil microorganisms can affect the accumulation of metals by plants either by directly or indirectly stimulating plant growth and activity or by (im)mobilizing and/or complexing metals. Understanding the intricate interplay of metal-accumulating plants with their rhizosphere microbiome is an important step toward the application and optimization of phytoremediation. We compared the effects of a "native" and a strongly disturbed (gamma-irradiated) soil microbial communities on cadmium and zinc accumulation by the plant Arabidopsis halleri in soil microcosm experiments. A. halleri accumulated 100% more cadmium and 15% more zinc when grown on the untreated than on the gamma-irradiated soil. Gamma irradiation affected neither plant growth nor the 1 M HCl-extractable metal content of the soil. However, it strongly altered the soil microbial community composition and overall cell numbers. Pyrosequencing of 16S rRNA gene amplicons of DNA extracted from rhizosphere samples of A. halleri identified microbial taxa (Lysobacter, Streptomyces, Agromyces, Nitrospira, "Candidatus Chloracidobacterium") of higher relative sequence abundance in the rhizospheres of A. halleri plants grown on untreated than on gamma-irradiated soil, leading to hypotheses on their potential effect on plant metal uptake. However, further experimental evidence is required, and wherefore we discuss different mechanisms of interaction of A. halleri with its rhizosphere microbiome that might have directly or indirectly affected plant metal accumulation. Deciphering the complex interactions between A. halleri and individual microbial taxa will help to further develop soil metal phytoextraction as an efficient and sustainable remediation strategy. PMID:25595759

  13. The hyperaccumulator Alyssum murale uses complexation with nitrogen and oxygen donor ligands for Ni transport and storage

    E-print Network

    Sparks, Donald L.

    in plant parts and extracted sap. Nickel is con- centrated in the dermal leaf and stem tissues of A. murale Laboratory, Department of Plant and Soil Sciences, University of Kentucky, N122S Agricultural Sciences North of Plant and Soil Sciences, University of Delaware, 152 Townsend Hall, Newark, DE 19717-1303, USA a r t i c

  14. Impact Assessment of Mercury Accumulation and Biochemical and Molecular Response of Mentha arvensis: A Potential Hyperaccumulator Plant

    PubMed Central

    Manikandan, R.; Sahi, S. V.; Venkatachalam, P.

    2015-01-01

    The present study was focused on examining the effect of Hg oxidative stress induced physiochemical and genetic changes in M. arvensis seedlings. The growth rate of Hg treated seedlings was decreased to 56.1% and 41.5% in roots and shoots, respectively, compared to the control. Accumulation of Hg level in both roots and shoots was increased with increasing the concentration of Hg. Superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities were found to be increased with increasing the Hg concentration up to 20?mg/L; however, it was decreased at 25?mg/L?Hg concentration. The POX enzyme activity was positively correlated with Hg dose. The changes occurring in the random amplification of ploymorphic DNA (RAPD) profiles generated from Hg treated seedlings included variations in band intensity, disappearance of bands, and appearance of new bands compared with the control seedlings. It was concluded that DNA polymorphisms observed with RAPD profile could be used as molecular marker for the evaluation of heavy metal induced genotoxic effects in plant species. The present results strongly suggested that Mentha arvensis could be used as a potential phytoremediator plant in mercury polluted environment. PMID:25654134

  15. Uptake of antimonite and antimonate by arsenic hyperaccumulator Pteris vittata: Effects of chemical analogs and transporter inhibitor

    E-print Network

    Ma, Lena

    analogs, Sb and As share many chemical properties and both exist in 3 and 5 oxidation state forms in the environment. The 3 oxidation state is found under anoxic conditions, whereas the 5 oxidation state occurs but with different affinities. For example, the transport protein AtNIP5; 1 and AtNIP6; 1 favor uptake of AsIII over

  16. Phytoremediation of Soil Trace Elements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytoremediation includes several distinct approaches to using plants to achieve soil remediation goals. Phytoextraction uses rare hyperaccumulator plants to accumulate in their shoots enough metals per year to achieve decontamination goals. Phytomining uses hyperaccumulators and biomass burn to pro...

  17. Selenium accumulation in flowers and its effects on pollination

    E-print Network

    Selenium accumulation in flowers and its effects on pollination Colin F. Quinn1 , Christine N juncea, floral visitor, hyperaccumulator, pollen germination, selenium (Se), Stanleya pinnata. Summary · Selenium (Se) hyperaccumulation has a profound effect on plant­arthropod interactions. Here, we

  18. Vegetative covers for sediment control and phosphorus sequestration from dairy waste application fields 

    E-print Network

    Giri, Subhasis

    2008-10-10

    (Chenopodium album), field pennycress (Thlaspi arvense), and foxtail (Setaria spp.). The new forest consisted of same grasses in “newgrass” plot, along with bush honeysuckle (Lonicera maackii), goldren current (Ribes aureum) and fast growing trees, eastern...

  19. Biodiesel From Alternative Oilseed Feedstocks: Production and Properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fatty acid methyl esters were prepared and evaluated as potential biodiesel fuels from several alternative oilseed feedstocks, which included camelina (Camelina sativa L.), coriander (Coriandrum sativum L.), field mustard (Brassica juncea L.), field pennycress (Thlaspi arvense L.), and meadowfoam (L...

  20. Survey of alternative feedstocks for biodiesel production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Summarized will be results obtained from the production of biodiesel from several alternative feedstocks with promising agronomic characteristics. Such feedstocks include camelina (Camelina sativa L.), coriander (Coriandrum sativum L.), field pennycress (Thlaspi arvense L.), and meadowfoam (Limnanth...

  1. Classification of specialty seed meals from NIR reflectance spectra

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Near infrared reflectance spectroscopy was used to identify alternative seed meals proposed for food and feed formulations. Spectra were collected from cold pressed Camelina (Camelina sativa), Coriander (Coriandrum sativum), and Pennycress (Thlaspi arvense) meals. Additional spectra were collected ...

  2. Current Biology 16, 21812192, November 21, 2006 2006 Elsevier Ltd All rights reserved DOI 10.1016/j.cub.2006.09.015 Selenium-Tolerant

    E-print Network

    .1016/j.cub.2006.09.015 Article Selenium-Tolerant Diamondback Moth Disarms Hyperaccumulator Plant Defense hyperaccumulate the toxic element selenium (Se) to extreme levels, up to 1% of dry weight. The function on the same site [1]. Selenium (Se)-hyperaccumulating plants such as Stanleya pinnata (Brassicaceae

  3. Identification and validation of heavy metal and radionuclide hyperaccumulating terrestrial plant species. Quarterly progress report, July 1, 1996--September 30, 1996

    SciTech Connect

    Kochian, L.

    1997-05-01

    Potential for phytoremediation of an aged radiocesium-contaminated soil from Brookhaven National Laboratory was investigated in three phases: (1) hydroponic screening for plant species capable of accumulating elevated levels of cesium in shoots, (2) amending contaminated soil to enhance {sup 137}Cs bioavailability, and (3) phytoextracting radiocesium with plant roots and its removal in harvested shoots. The bioaccumulation ratio of Cs in shoots of hydroponically grown plants ranged between 38 and 165. From solution, dicot species accumulated 2- to 4-fold more cesium in shoots than grasses. The effect of several chemical compounds on {sup 137}Cs desorption from the contaminated soil was investigated. Ammonium salts were the most effective at desorbing Cs from contaminated soil, but only 25% of radiocesium could be desorbed. Although release of radiocesium from the soil was concentration-dependent, this effect appeared to level off above 0.2 M ammonium in solution. In a pot study, from the soil contaminated with 400 pCi g{sup -1} soil, the greatest amount of {sup 137}Cs, 140 pCi, was removed in shoots of cabbage (Brassica oleracea var. capitata). {sup 137}Cs accumulation in shoots was significantly increased by the addition of 40 NH{sub 4}NO{sub 3} kg{sup -1} soil. Increasing NH{sub 4}NO{sub 3} application from 40 to 80 mmoles kg{sup -1} soil did not further increase radiocesium phytoextraction. The ability to accumulate radiocesium from soil in shoots was significantly different among species tested. This ability increased in order: reed Canary grass (Phalaris arundinacea) < Indian mustard (Brassica juncea) < tepary bean (Phaseolus acutifolius) < cabbage.

  4. Identification and validation of heavy metal and radionuclide hyperaccumulating terrestrial plant species. Quarterly technical progress report, March 20, 1995--June 20, 1995

    SciTech Connect

    Kochian, L.

    1995-12-01

    The biological accumulation of heavy metals and cesium, strontium, and uranium in plants is discussed. The role of nutrient deficiencies and foliar treatments of manganese and iron compounds is described.

  5. Monitoring of the heavy-metal hyperaccumulation in vegetal tissues by X-ray radiography and by femto-second laser induced breakdown spectroscopy.

    PubMed

    Kaiser, J; Samek, O; Reale, L; Liska, M; Malina, R; Ritucci, A; Poma, A; Tucci, A; Flora, F; Lai, A; Mancini, L; Tromba, G; Zanini, F; Faenov, A; Pikuz, T; Cinque, G

    2007-02-01

    This article reports on the utilization of X-ray microradiography and laser induced breakdown spectroscopy (LIBS) techniques for investigation of the metal accumulation in different part of leaf samples. The potential of the LIBS-analysis for finding the proper plant species for phytoremediation is compared with the results of microradiography measurements at the HERCULES source at ENEA, Rome (Italy) and X-ray microradiography experiments at the ELETTRA Synchrotron, Trieste (Italy). PMID:17131357

  6. IN SITU SPECIATION OF COBALT IN NI/CO HYPERACCUMULATOR ALYSSUM MURALE USING BULK AND MICRO-FOCUSED X-RAY ABSORPTION SPECTROSCOPY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The long-term fate of trace metals in contaminated soil systems is a significant issue in environmental chemistry. Unique plant species have evolved an ability to accumulate large quantities of trace metals in their harvestable biomass, and thereby offer a sustainable method for treatment of metal c...

  7. Bioremediation of Cd-DDT co-contaminated soil using the Cd-hyperaccumulator Sedum alfredii and DDT-degrading microbes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of an integrated strategy for the remediation of soil co-contaminated by heavy metals and persistent organic pollutants is a major research priority for the decontamination of soil slated for use in agricultural production. The objective of this study was to develop a bioremediation ...

  8. Soil and Biota of Serpentine: A World View 2009 Northeastern Naturalist 16(Special Issue 5):139154

    E-print Network

    Boyd, Robert S.

    tested whether epiphytes (mosses and liverworts) growing on Ni hyperaccu- mulator hosts contained greater hyperaccumulate Ni. Six of the epiphytes we analyzed, four liverworts (Frullania ramuligera, Schistochila sp

  9. This article was downloaded by: [Colorado State University] On: 25 August 2011, At: 09:14

    E-print Network

    of invertebrate and vertebrate herbivores, due to both deterrence and toxicity. However, specialist (Se- tolerant herbivores), detritivores and endophytes appear to utilize Se hyperaccumulator plants as a resource

  10. DEVELOPMENT OF BIO-BASED MOLECULAR TECHNOLOGIES FOR REMOVAL AND REAL-TIME MONITORING OF TOXIC METALS

    EPA Science Inventory

    Transformation of heavy-metal related genes from a hyper-accumulator to a high-biomass species is expected to promote a zinc hyper-accumulating phenotype in the normally non-hyper-accumulating poplar. Coupling fluorescence with heavy metal proteins is anticipated to allow ...

  11. Stormy Dawn Lindblom Curriculum Vitae

    E-print Network

    ) Selenium hyperaccumulating plants are protected from the cell disruptor herbivores two-spotted spider mites; plant- microbe interactions in hyperaccumulator plants. Undergraduate research Sept. 2000 ­ Dec. 2008 Engineering Approaches for the Study of Plant Selenium Metabolism: 2. Evolutionary and Ecological Aspects

  12. ORIGINAL RESEARCH ARTICLE published: 23 January 2015

    E-print Network

    -hyperaccumulator Brassica juncea with respect to S-dependent selenate uptake and translocation, as well as for the expression levels of three sulfate/selenate transporters (Sultr) and three ATP sulphurylases (APS). Selenium selenate specificity over sulfate. Also, the hyperaccumulator has elevated expression levels of several

  13. Bacterial Inoculants Affecting Nickel Uptake by Alyssum murale From Low, Moderate and High Ni Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metal hyperaccumulator plants like Alyssum murale have a remarkable ability to hyperaccumulate Ni from soils containing mostly insoluble Ni. We have shown some rhizobacteria increase the phytoavailability of Ni in soils, thus enhancing Ni accumulation by A. murale. Nine bacterial strains, originally...

  14. Chemoecology 8 (1998) 17 09377409/98/01000107 $1.50+0.20

    E-print Network

    Boyd, Robert S.

    1998-01-01

    -metal plant litter will host a specialized microflora of decomposers and may affect nutrient cycling rates mechanisms may require biotic vectors that might be affected by plant metal content. Hyperaccumulating plants, University of California, Davis, CA 95616, USA Abstract. Metal hyperaccumulating plants contain very high

  15. Poplar maintains zinc homeostasis with heavy metal genes HMA4 and PCS1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This project has identified two large gene families, HMA and ZIP, in poplar that have been greatly expanded by the latest Salicoid genome duplication in poplar. In other species, these two families have been shown to be central in both hyperaccumulators and non-hyperaccumulators In poplar, many of t...

  16. Physiologia Plantarum 152: 7083. 2014 2014 Scandinavian Plant Physiology Society, ISSN 0031-9317 Analysis of selenium accumulation, speciation and tolerance

    E-print Network

    -9317 Analysis of selenium accumulation, speciation and tolerance of potential selenium hyperaccumulator earlier to contain hyperaccumulator levels of selenium (Se) in the field (>1000 mg kg-1 dry weight (DW by a physiological benefit, in addition to the ecological benefit demonstrated earlier. Introduction Selenium

  17. Symphyotrichum ericoides populations from seleniferous and nonseleniferous soil display striking variation in selenium

    E-print Network

    variation in selenium accumulation Ali F. El Mehdawi1 , Mark W. Paschke2 and Elizabeth A. H. Pilon-Smits1 1, facultative metallophyte, hyperaccumulation, rhizosphere microbes, selenium, Symphyotrichum ericoides. Summary to have selenium (Se) hyperaccumulator properties in field and glasshouse studies, and to benefit from Se

  18. Trends in literature on new oilseed crops and related species: Seeking evidence of increasing or waning interest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bibliographic records on eight new crop species Camelina, Crambe, Cuphea, Physaria, Limnanthes, Stokesia, Thlaspi, and Vernonia from Agricola, CAB Abstracts, Scopus, and Web of Science were analyzed for historical and recent trends in the areas of research, author distribution, and quantity and impa...

  19. Biodiesel Prepared From Field Pennycress Oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field pennycress (Thlaspi arvense L., FP) is a winter annual species of the mustard family (Brassicaceae) which is widely distributed throughout temperate North America that can serve as a winter rotational crop for conventional crops, thus not displacing farm land or negatively impacting the food s...

  20. EVALUATION OF FIELD PENNYCRESS AS AN OVERWINTER GREEN MANURE CROP IN CORN FOR SUPPRESSION OF WESTERN CORN ROOTWORM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field pennycress (FP; Thlaspi arvense L.) is a winter annual species of the Brassicaceae which is a native of Europe but has a wide distribution throughout temperate North America. FP tissues contain the glucosinolate sinigrin, and release a mixture of the biocides allyl thiocyanate and allyl isoth...

  1. Collecting field pennycress germplasm in Colorado and characterization of oil and root variation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field pennycress (Thlaspi arvense) has been identified as a possible source of biodiesel that may perform better in colder climates than other biodiesel fuels. A germplasm collection of the species is being maintained by the U.S. Department of Agriculture for use in research, education, and crop imp...

  2. Comparison of the emergence of three Brassicaceae species of different origins grown in Spain and USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thlaspi arvense, Camelina sativa, C. microcarpa and Neslia paniculata are four Brassicaceae family species that are becoming rare in North-Eastern Spain. Conversely, both T. arvense and C. sativa are being investigated as oilseed crops in North America for industrial/biofuel purposes. C. microcarpa ...

  3. The Niemann-Pick C1 Protein Functions in Regulating Lysosome Amine Content

    E-print Network

    Kaufmann, Allyn

    2008-01-01

    Mutations in the lysosome membrane protein Niemann-Pick C1 (NPC1) are known to cause a generalized block in retrograde vesicle-mediated transport from the lysosome, resulting in the hyper-accumulation of multiple lysosomal ...

  4. This article was downloaded by: [Colorado State University] On: 01 June 2015, At: 14:39

    E-print Network

    , Symphyotrichum ericoides and Chenopodium album growing next to Se hyperaccumulators or non-accumulators at a seleniferous site. Regardless of neighbors, A. ludoviciana, S. ericoides and C. album accumulated pre

  5. Metallophytes for organic synthesis: towards new bio-based selective protection/deprotection procedures.

    PubMed

    Grison, Claire M; Velati, Alicia; Escande, Vincent; Grison, Claude

    2015-04-01

    We propose for the first time using metal hyperaccumulating plants for the construction of a repertoire of protection and deprotection conditions in a concept of orthogonal sets. Protection of alcohol, carbonyl, carboxyl, and amino groups are considered. The ecocatalysts derived from metal-rich plants allow selective, mild, eco-friendly, and efficient protection or deprotection reactions. The selectivity is controlled by the choice of the metal, which is hyperaccumulated by the metallophyte. PMID:25226830

  6. This journal is c The Royal Society of Chemistry 2013 Metallomics Cite this: DOI: 10.1039/c3mt00215b

    E-print Network

    b Thlaspi arvense binds Cu(II) as a bis-(L-histidinato) complex on root cell walls in an urban,b Sylvain Bohic,bc Sirine C. Fakra,d Matthew A. Marcus,d Jean-Philippe Bedelle and Kathryn L. Nagyf Root as a unique five- coordinate Cu(II)­bis(L-histidinato) complex with one L-histidine behaving as a tridentate

  7. Variation in Heavy Metal Accumulation and Genetic Diversity at a Regional Scale Among Metallicolous and Non-Metallicolous Populations of the Facultative Metallophyte Biscutella laevigata subsp. laevigata.

    PubMed

    Poš?i?, Filip; Fellet, Guido; Vischi, Massimo; Casolo, Valentino; Schat, Henk; Marchiol, Luca

    2015-01-01

    Biscutella laevigata is a facultative metallophyte, with populations on non-metalliferous and metalliferous soils. Some of its metallicolous populations have been shown to hyperaccumulate thallium or lead in nature. Only Tl hyperaccumulation has been experimentally confirmed. We aimed to compare the patterns of metal (hyper)accumulation and genetic diversity among populations of B. laevigata subsp. laevigata in NE Italy. None of the populations exhibited foliar hyperaccumulation of Cu, Zn, or Pb. The root-to-shoot accumulation rates for these metals were unchanged or decreased rather than enhanced in the metallicolous populations, in comparison with the non-metallicolous ones. Hyperaccumulation of Tl was confined to the population of the Cave del Predil mine. This population was genetically very distinct from the others, as demonstrated by AFLP-based cluster analysis. The two other mine populations did not surpass the threshold for Tl hyperaccumulation, but showed enhanced foliar Tl concentrations and root-to-shoot translocation rates, in comparison with the non-metallicolous populations. Genetic analysis suggested that adaptation to metalliferous soil must have been independently evolved in the metallicolous populations. PMID:25495937

  8. Symphyotrichum ericoides populations from seleniferous and nonseleniferous soil display striking variation in selenium accumulation.

    PubMed

    El Mehdawi, Ali F; Paschke, Mark W; Pilon-Smits, Elizabeth A H

    2015-04-01

    Symphyotrichum ericoides (Asteraceae) from naturally seleniferous habitat (Pine Ridge) was shown previously to have selenium (Se) hyperaccumulator properties in field and glasshouse studies, and to benefit from Se through protection from herbivory. To investigate whether Se hyperaccumulation is ubiquitous in S. ericoides or restricted to seleniferous soils, the S. ericoides Pine Ridge (PR) population was compared with the nearby Cloudy Pass (CP) population from nonseleniferous soil. The S. ericoidesPR and CP populations were strikingly physiologically different: in a common garden experiment, PR plants accumulated up to 40-fold higher Se concentrations than CP plants and had 10-fold higher Se : sulfur (S) ratios. Moreover, roots of S. ericoidesPR plants showed directional growth toward selenate, while CP roots did not. Growth of both accessions responded positively to Se. Each accession grew best on its own soil. Rhizosphere soil inoculum from the S. ericoidesPR population stimulated plant growth and Se accumulation in both S. ericoidesPR and S. ericoidesCP plants, on both PR and CP soils. While the S. ericoidesPR population hyperaccumulates Se, the nearby CP population does not. The capacity of S. ericoidesPR plants to hyperaccumulate Se appears to be a local phenomenon that is restricted to seleniferous soil. Mutualistic rhizosphere microbes of the S. ericoidesPR population may contribute to the hyperaccumulation phenotype. PMID:25406635

  9. Pint-sized plants pack a punch in fight against heavy metals

    SciTech Connect

    Boyd, V.

    1996-05-01

    USDA researchers are experimenting with plants that naturally scavenge heavy metals such as cadmium and zinc from the soil. Known as hyperaccumulators, the plants can store up to 2.5% of their dry weight in heavy metals in leaves without yield reductions. They can be grown, harvested, and dried. The dried material is then burned, and the metal ore can be recovered. As well as discussing the history of hyperaccumulators, this article focuses on the plant pennycress and work on improving its metal uptake.

  10. Effects of arsenic on concentration and distribution of nutrients in the fronds of the arsenic

    E-print Network

    Ma, Lena

    Effects of arsenic on concentration and distribution of nutrients in the fronds of the arsenic, Gainesville, FL 32611-0290, USA Received 20 October 2003; accepted 29 March 2004 Arsenic hyperaccumulator P. vittata maintained adequate levels of essential nutrients in the fronds under arsenic stress. Abstract

  11. Effects of Cadmium on Nickel Tolerance and Accumulation in Alyssum species and Cabbage Grown in Nutrient Solution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nickel phytoextraction using hyperaccumulator plant species to accumulate Ni from mineralized and contaminated soils rich in Ni is an emerging technology. Serpentinite derived soils which contain Ni ore value have a very low ratio of Ca:Mg among soils due the nature of the parent rock. In crop plant...

  12. The Engineered Phytoremediation of Ionic and Methylmercury Pollution

    SciTech Connect

    Richard Meagher; Sarah Marshburn; Andrew Heaton; Anne Marie Zimer; Raoufa Rahman

    2003-06-24

    Our current specific objectives are to use transgenic plants to control the chemical species, electrochemical state, and above ground binding of mercury to (a) prevent methylmercury from entering the food-chain, (b) remove mercury from polluted sites, and (c) hyperaccumulate mercury in above ground tissues for later harvest.

  13. Author's personal copy Environmental and Experimental Botany 65 (2009) 282286

    E-print Network

    Ma, Lena

    2009-01-01

    .elsevier.com/locate/envexpbot Arsenic reduced scale-insect infestation on arsenic hyperaccumulator Pteris vittata L. Shiny Mathewsa exposure (0, 5, 15 and 30 mg kg-1 ) on scale insect (Saissetia neglecta) infestation of P. vittata. Scale arsenic concentrations resulted in higher percentage of fallen-scale insects (17.2­55.0%). Lower arsenic

  14. Expression of an "Arabidopsis" Ca(2+)/H(+) antiporter CAX1 variant in petunia enhances cadmium tolerance and accumulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytoremediation is a cost-effective and minimally invasive technology to cleanse soils contaminated with heavy metals. However, few plant species are suitable for phytoremediation of metals such as cadmium (Cd). Genetic engineering offers a powerful tool to generate plants that can hyperaccumulate ...

  15. NiO(s) (Bunsenite) is not Available to Alyssum species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    AIMS: To determine if the Ni-hyperaccumulator Alyssum corsicum can absorb Ni from the kinetically inert crystalline mineral NiO(s) (bunsenite). METHODS: A. corsicum and A. montanum plants were grown for 30 days in a serpentine Hoagland solution. NiO was provided at 0 or 0.1 g L-1 (1.34 mmol L-1) ...

  16. SYNCHROTRON X-RAY ABSORPTION-EDGE COMPUTED MICROTOMOGRAPHY IMAGING OF THALLIUM COMPARTMENTALIZATION IN IBERIS INTERMEDIA

    EPA Science Inventory

    Thallium (TI) is an extremely toxic metal which, due to its similarities to K, is readily taken up by plants. Thallium is efficiently hyperaccumulated in Iberis intermedia as TI(I). Distribution and compartmentalization of TI in I. intermedia is highes...

  17. AREA 5 WASTE DISPOSAL RESEARCH ARTICLE Biomass reduction and arsenic transformation

    E-print Network

    Ma, Lena

    and arsenic transformation during com- posting As-rich biomass of hyperaccumulator Chinese brake fern (Pteris vittata L.). Materials and methods High-As fern biomass containing 4,600 mg As kg-1 was composted for 120 reduced the fern biomass by 38%, comparable to 35% reduction of the low-As fern biomass containing 12 mg

  18. ontamination of soils with arsenic, which is both toxic and carcinogenic,

    E-print Network

    Ma, Lena

    have discovered that the fern Pteris vittata (brake fern) is extremely efficient in extracting arsenic, is the first known arsenic hyperaccumulator as well as the first fern found to function as a hyper- accumulator. We found brake fern growing on a site in Central Florida contaminated with chromated copper arsenate

  19. Plant and Soil 258: 919, 2004. 2004 Kluwer Academic Publishers. Printed in the Netherlands.

    E-print Network

    Ma, Lena

    Abstract This study compared the roles of root exudates collected from two fern species, the As hyperaccumulating Chinese Brake fern (Pteris vittata L.) and the As-sensitive Boston fern (Nephrolepis exaltata L arsenate)-contaminated soil as well as plant As accumulation. Chinese Brake fern exuded 2 times more

  20. A critical review on the bio-removal of hazardous heavy metals from contaminated soils: issues, progress, eco-environmental concerns and opportunities.

    PubMed

    Wu, Gang; Kang, Hubiao; Zhang, Xiaoyang; Shao, Hongbo; Chu, Liye; Ruan, Chengjiang

    2010-02-15

    Mechanism of four methods for removing hazardous heavy metal are detailed and compared-chemical/physical remediation, animal remediation, phytoremediation and microremediation with emphasis on bio-removal aspects. The latter two, namely the use of plants and microbes, are preferred because of their cost-effectiveness, environmental friendliness and fewer side effects. Also the obvious disadvantages of other alternatives are listed. In the future the application of genetic engineering or cell engineering to create an expected and ideal species would become popular and necessary. However, a concomitant and latent danger of genetic pollution is realized by a few persons. To cope with this potential harm, several suggestions are put forward including choosing self-pollinated plants, creating infertile polyploid species and carefully selecting easy-controlled microbe species. Bravely, the authors point out that current investigation of noncrop hyperaccumulators is of little significance in application. Pragmatic development in the future should be crop hyperaccumulators (newly termed as "cropaccumulators") by transgenic or symbiotic approach. Considering no effective plan has been put forward by others about concrete steps of applying a hyperaccumulator to practice, the authors bring forward a set of universal procedures, which is novel, tentative and adaptive to evaluate hyperaccumulators' feasibility before large-scale commercialization. PMID:19864055

  1. Expression of a Pteris vittata glutaredoxin PvGRX5 in transgenic Arabidopsis thaliana increases plant arsenic

    E-print Network

    Ma, Lena

    plant arsenic tolerance and decreases arsenic accumulation in the leaves SABARINATH SUNDARAM1 , SHAN WU1, USA ABSTRACT Chinese brake fern Pteris vittata hyperaccumulates arsenic in its fronds. In a study to identify brake fern cDNAs in arsenic resistance, we implicated a glutaredoxin, PvGRX5, because when

  2. Author's personal copy Arsenic-resistant bacteria solubilized arsenic in the growth media

    E-print Network

    Ma, Lena

    Author's personal copy Arsenic-resistant bacteria solubilized arsenic in the growth media and increased growth of arsenic hyperaccumulator Pteris vittata L. Piyasa Ghosh a , Bala Rathinasabapathi b bacteria As solubilization Plant growth promotion a b s t r a c t The role of arsenic-resistant bacteria

  3. Characteristics of arsenic accumulation by Pteris and non-Pteris ferns T. Luongo & L.Q. Ma1

    E-print Network

    Ma, Lena

    Characteristics of arsenic accumulation by Pteris and non-Pteris ferns T. Luongo & L.Q. Ma1 Soil author* Received 8 March 2005. Accepted in revised form 24 April 2005 Key words: arsenic, detoxification the mechanisms of arsenic hyperaccumulation in Pteris vittata by comparing the characteristics of arsenic

  4. Author's personal copy Sulfate and glutathione enhanced arsenic accumulation by arsenic

    E-print Network

    Ma, Lena

    Author's personal copy Sulfate and glutathione enhanced arsenic accumulation by arsenic, Gainesville, FL 32611-0690, USA Sulfate and glutathione increased arsenic uptake and translocation in Pteris December 2009 Accepted 12 December 2009 Keywords: Sulfur Arsenic Hyperaccumulator GSH a b s t r a c

  5. Accumulation of zinc and cadmium and localization of zinc in Picris divaricata

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Picris divaricata Vant., native to subtropical China, was recently identified as the first Cd/Zn hyper-accumulator from Asteraceae. Wild collected seed of P. divaricata was grown in a series of pH buffered test soils with Zn levels 00-7000 gkg-1 and Cd levels 00-150 gkg-1 for four months. Plants d...

  6. , Edward Peltier, R. L. Chaney, and Donald Sparks. The ASA-CSSA-SSSA International Annual Meetings

    E-print Network

    Sparks, Donald L.

    spectroscopy (XAFS) to resolve the speciation of Co within the roots, stems, and leaves of plants. Preliminary is part of: Trace Elements in Soils and Plants: I Speciation of Cobalt in Ni/Co Hyperaccumulator Using. Unique plant species have evolved an ability to accumulate large quantities of trace metals

  7. Assessing Plants for Phytoremediation of Arsenic-Contaminated Soils

    E-print Network

    Ma, Lena

    by roots and translocation from roots to shoots. Specifically, how does a plant acquire and maintain24 Assessing Plants for Phytoremediation of Arsenic-Contaminated Soils Nandita Singh and Lena Q. Ma- chemistry of As in plants, (2) plant hyperaccumulation of inorganics including As, (3) the phenomenon

  8. DEVELOPMENT OF A NEW TECHNOLOGY FOR PHYTOEXTRACTION OF NICKEL - COMMERCIAL CONSIDERATIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have made important progress in developing a commercial technology using hyperaccumulator plant species to phytoextract nickel (Ni) from contaminated and/or Ni-rich soils. Development of such a technology required identifying or creating an ideal phytoextraction plant, optimizing soil and crop m...

  9. Chemoecology 15:179185 (2005) 09377409/05/0301797

    E-print Network

    Boyd, Robert S.

    2005-01-01

    00049-005-0310-z CHEMOECOLOGY A test of elemental defence against slugs by Ni in hyperaccumulator . Plants of all species grown on low-Ni soils had Slugs (Limax maximus) were fed plant material in no-choice tests over a 50-day period and survival and mass changes were recorded. All slugs fed

  10. Gene expression differences between Noccaea caerulescens ecotypes help to identify candidate genes for metal phytoremediation.

    PubMed

    Halimaa, Pauliina; Lin, Ya-Fen; Ahonen, Viivi H; Blande, Daniel; Clemens, Stephan; Gyenesei, Attila; Häikiö, Elina; Kärenlampi, Sirpa O; Laiho, Asta; Aarts, Mark G M; Pursiheimo, Juha-Pekka; Schat, Henk; Schmidt, Holger; Tuomainen, Marjo H; Tervahauta, Arja I

    2014-03-18

    Populations of Noccaea caerulescens show tremendous differences in their capacity to hyperaccumulate and hypertolerate metals. To explore the differences that could contribute to these traits, we undertook SOLiD high-throughput sequencing of the root transcriptomes of three phenotypically well-characterized N. caerulescens accessions, i.e., Ganges, La Calamine, and Monte Prinzera. Genes with possible contribution to zinc, cadmium, and nickel hyperaccumulation and hypertolerance were predicted. The most significant differences between the accessions were related to metal ion (di-, trivalent inorganic cation) transmembrane transporter activity, iron and calcium ion binding, (inorganic) anion transmembrane transporter activity, and antioxidant activity. Analysis of correlation between the expression profile of each gene and the metal-related characteristics of the accessions disclosed both previously characterized (HMA4, HMA3) and new candidate genes (e.g., for nickel IRT1, ZIP10, and PDF2.3) as possible contributors to the hyperaccumulation/tolerance phenotype. A number of unknown Noccaea-specific transcripts also showed correlation with Zn(2+), Cd(2+), or Ni(2+) hyperaccumulation/tolerance. This study shows that N. caerulescens populations have evolved great diversity in the expression of metal-related genes, facilitating adaptation to various metalliferous soils. The information will be helpful in the development of improved plants for metal phytoremediation. PMID:24559272

  11. DEGRADATION OF ALYSSUM BIOMASS IN SOIL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The reasons for Ni hyperaccumulation remain unproven; however, elemental allelopathy has been suggested as a possible reason for this unusual trait. It has been suggested that continual transport of Ni from soil to leaves, then shedding of leaves to fall on the soil surface, may create a Ni toxic zo...

  12. NiO (bunsenite) is not available to Alyssum species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some species of the genus Alyssum are capable of accumulating up to 30 g kg-1 DW Ni in their leaves when grown on serpentine soils where these species are endemic. The unique ability of Alyssum species to hyperaccumulate high concentration of Ni stimulated basic research toward a better understandi...

  13. International Journal of Phytoremediation, 14:939949, 2012 Copyright C Taylor & Francis Group, LLC

    E-print Network

    Ma, Lena

    (As) hyperaccumulating plants can be used to remove As from contaminated soils. Its effectiveness, Gainesville, Florida, USA 3 State Key Laboratory of Pollution Control and Resource Reuse, School, Aracaj´u, Brazil Using chemical extraction to evaluate plant arsenic availability in contaminated soils

  14. DOI 10.1007/s00442-007-0907-8 PLANT-ANIMAL INTERACTIONS -ORIGINAL PAPER

    E-print Network

    of selenium in protecting plants against prairie dog herbivory: implications for the evolution of selenium by black-tailed prairie dogs (Cynomys ludovicianus). The Se hyperaccumulator Astragalus bisulcatus (two-grooved milkvetch) occurs nat- urally on seleniferous soils in the Western USA, often on prairie dog colonies. Field

  15. Soil and Water Science Department University of Florida Phytoremediation of Arsenic Contaminated Sites: Feasibility and Optimization

    E-print Network

    Ma, Lena

    contaminated with heavy metals, except for arsenic. We have discovered the only known arsenic hyperaccumulating is of great environmental concern due to its extensive contamination and carcinogenic toxicity demonstration. The effectiveness of the plants in removing different arsenic species at different concentrations

  16. 490 www.newphytologist.org To investigate whether selenium (Se) accumulation in plants provides a chemical

    E-print Network

    490 www.newphytologist.org Research Summary · To investigate whether selenium (Se) accumulation and performance of a mix of orthopteran species were investigated. · The selenium hyperaccumulator Stanleya demonstrate that both inorganic and organic forms of selenium protect plants from herbivory. Grasshoppers fed

  17. Selenium accumulation in flowers and its effects on pollination

    E-print Network

    Selenium accumulation in flowers and its effects on pollination 1 Colin F. Quinn1 , Christine N, floral visitor, hyperaccumulator, pollen germination, selenium (Se), Stanleya pinnata. Summary · Selenium for the management of seleniferous areas. Introduction Selenium (Se) is both an essential nutrient and a toxin

  18. Selenium accumulation in flowers and its effects on pollination

    E-print Network

    Selenium accumulation in flowers and its effects on pollination Colin F. Quinn1 , Christine N, floral visitor, hyperaccumulator, pollen germination, selenium (Se), Stanleya pinnata. Summary · Selenium for the management of seleniferous areas. Introduction Selenium (Se) is both an essential nutrient and a toxin

  19. ORIGINAL ARTICLE Inoculation of Astragalus racemosus and Astragalus convallarius

    E-print Network

    affect plant selenium (Se) accumulation. Here we investigate the effects of two fungi on Se accumulation and biofortification. Keywords Plant­microbe interactions Á Hyperaccumulation Á Alternaria astragali Á FusariumCys) occurs in selenoproteins, which perform essential functions in many animals, bacteria, and algae

  20. Chelator-buffered nutrient solution is ineffective in extracting Ni from seeds of Alyssum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hyperaccumulator species of the genera Alyssum can accumulate 100 times more Ni than normal crops and are therefore used for phytomining and phytoextraction of nickel contaminated soils. Basic studies on the physiology and metal uptake mechanisms of these plants are needed to increase efficiency and...

  1. Xylem exudate composition and root-to-shoot nickel translocation in Alyssum species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An improved understanding of Ni root-to-shoot translocation mechanism in hyperaccumulators is necessary to increase Ni uptake efficiency for phytoextraction technologies. It is presumed that an important aspect of Ni translocation and storage involves chelation with organic ligands. It has been re...

  2. Phytoremediation of ionic and methylmercury pollution

    SciTech Connect

    Meagher, Richard B

    2010-04-28

    Our long-term goal is to enable highly productive plant species to extract, resist, detoxify, and sequester the toxic elemental pollutants, like the heavy metal mercury. Our current working hypothesis is that transgenic plants controlling the transport, chemical speciation, electrochemical state. volatilization, and aboveground binding of mercury will: a) tolerate mercury and grow rapidly in mercury contaminated environments; b) prevent methylmercury from entering the food chain; c) remove mercury from polluted soil and . water; and d) hyperaccumulate mercury in aboveground tissues for later harvest. Progress toward these specific aims is reported: to increase the transport of mercury into roots and to aboveground vegetative organs; to increase biochemical sinks and storage for mercury in leaves; to increase leaf cell vacuolar storage of mercury; and to demonstrate that several stacked transgenes, when functioning in concert, enhance mercury resistance and hyperaccumulation to high levels.

  3. Enhancement of Phosphate Absorption by Garden Plants by Genetic Engineering: A New Tool for Phytoremediation

    PubMed Central

    Togami, Junichi; Mason, John G.; Chandler, Stephen F.; Tanaka, Yoshikazu

    2013-01-01

    Although phosphorus is an essential factor for proper plant growth in natural environments, an excess of phosphate in water sources causes serious pollution. In this paper we describe transgenic plants which hyperaccumulate inorganic phosphate (Pi) and which may be used to reduce environmental water pollution by phytoremediation. AtPHR1, a transcription factor for a key regulator of the Pi starvation response in Arabidopsis thaliana, was overexpressed in the ornamental garden plants Torenia, Petunia, and Verbena. The transgenic plants showed hyperaccumulation of Pi in leaves and accelerated Pi absorption rates from hydroponic solutions. Large-scale hydroponic experiments indicated that the enhanced ability to absorb Pi in transgenic torenia (AtPHR1) was comparable to water hyacinth a plant that though is used for phytoremediation causes overgrowth problems. PMID:23984322

  4. Phytoremediative urban design: transforming a derelict and polluted harbour area into a green and productive neighbourhood.

    PubMed

    Wilschut, M; Theuws, P A W; Duchhart, I

    2013-12-01

    Many urban areas are polluted by industrial activities and waste disposal in landfills. Since conventional soil remediation techniques are costly and unsustainable, phytoremediation might offer an alternative. In this article, we explore how phytoremediation can be integrated into the transformation of urban post-industrial areas, while improving public space. Buiksloterham, a polluted and deprived industrial area in Amsterdam, serves as case study. Buiksloterham is polluted with heavy metals, with Zinc (Zn) concentrations being the highest. A regression-model for Alpine Pennycress (Thlaspi caerulescens) is used to estimate the time needed to remediate the site. This reveals a conflict in time between remediation and urban development. A research by design experiment shows how to overcome this conflict by dealing with polluted soil innovatively while emphasizing spatial and aesthetic qualities of the phytoremediation plant species. The resulting landscape framework integrates phytoremediation with biomass production and gives new ecological, economic and social value to Buiksloterham. PMID:23452757

  5. Analysis of Sulfur And Selenium Assimilation in 'Astragalus' Plants With Varying Capacities to Accumulate Selenium

    SciTech Connect

    Sors, T.G.; Ellis, D.R.; Na, G.Nam.; Lahner, B.; Lee, S.; Leustek, T.; Pickering, I.J.; Salt, D.E.; /Purdue U. /Rutgers U., Piscataway /Saskatchewan U.

    2007-08-08

    Several Astragalus species have the ability to hyperaccumulate selenium (Se) when growing in their native habitat. Given that the biochemical properties of Se parallel those of sulfur (S), we examined the activity of key S assimilatory enzymes ATP sulfurylase (ATPS), APS reductase (APR), and serine acetyltransferase (SAT), as well as selenocysteine methyltransferase (SMT), in eight Astragalus species with varying abilities to accumulate Se. Se hyperaccumulation was found to positively correlate with shoot accumulation of S-methylcysteine (MeCys) and Se-methylselenocysteine (MeSeCys), in addition to the level of SMT enzymatic activity. However, no correlation was observed between Se hyperaccumulation and ATPS, APR, and SAT activities in shoot tissue. Transgenic Arabidopsis thaliana overexpressing both ATPS and APR had a significant enhancement of selenate reduction as a proportion of total Se, whereas SAT overexpression resulted in only a slight increase in selenate reduction to organic forms. In general, total Se accumulation in shoots was lower in the transgenic plants overexpressing ATPS, PaAPR, and SAT. Root growth was adversely affected by selenate treatment in both ATPS and SAT overexpressors and less so in the PaAPR transgenic plants. Such observations support our conclusions that ATPS and APR are major contributors of selenate reduction in planta. However, Se hyperaccumulation in Astragalus is not driven by an overall increase in the capacity of these enzymes, but rather by either an increased Se flux through the S assimilatory pathway, generated by the biosynthesis of the sink metabolites MeCys or MeSeCys, or through an as yet unidentified Se assimilation pathway.

  6. Author's personal copy Environmental and Experimental Botany 68 (2010) 222229

    E-print Network

    Ma, Lena

    2010-01-01

    vittata Silicic acid Boric acid Mercury a b s t r a c t To better understand arsenite (AsIII) uptake via aquaporin channels by arsenic hyperaccumulator Pteris vittata, the effects of silicic and boric acid (As with or without 0.5 mM silicic acid (Si experiment) or 0.3 mM boric acid (B experiment), or (2) 15 M AsIII for 2 d

  7. Agromining: farming for metals in the future?

    PubMed

    van der Ent, Antony; Baker, Alan J M; Reeves, Roger D; Chaney, Rufus L; Anderson, Christopher W N; Meech, John A; Erskine, Peter D; Simonnot, Marie-Odile; Vaughan, James; Morel, Jean Louis; Echevarria, Guillaume; Fogliani, Bruno; Rongliang, Qiu; Mulligan, David R

    2015-04-21

    Phytomining technology employs hyperaccumulator plants to take up metal in harvestable plant biomass. Harvesting, drying and incineration of the biomass generates a high-grade bio-ore. We propose that "agromining" (a variant of phytomining) could provide local communities with an alternative type of agriculture on degraded lands; farming not for food crops, but for metals such as nickel (Ni). However, two decades after its inception and numerous successful experiments, commercial phytomining has not yet become a reality. To build the case for the minerals industry, a large-scale demonstration is needed to identify operational risks and provide "real-life" evidence for profitability. PMID:25700109

  8. Zinc triggers a complex transcriptional and post-transcriptional regulation of the metal homeostasis gene FRD3 in Arabidopsis relatives

    PubMed Central

    Charlier, Jean-Benoit; Polese, Catherine; Nouet, Cécile; Carnol, Monique; Bosman, Bernard; Krämer, Ute; Motte, Patrick; Hanikenne, Marc

    2015-01-01

    In Arabidopsis thaliana, FRD3 (FERRIC CHELATE REDUCTASE DEFECTIVE 3) plays a central role in metal homeostasis. FRD3 is among a set of metal homeostasis genes that are constitutively highly expressed in roots and shoots of Arabidopsis halleri, a zinc hyperaccumulating and hypertolerant species. Here, we examined the regulation of FRD3 by zinc in both species to shed light on the evolutionary processes underlying the evolution of hyperaccumulation in A. halleri. We combined gene expression studies with the use of ?-glucuronidase and green fluorescent protein reporter constructs to compare the expression profile and transcriptional and post-transcriptional regulation of FRD3 in both species. The AtFRD3 and AhFRD3 genes displayed a conserved expression profile. In A. thaliana, alternative transcription initiation sites from two promoters determined transcript variants that were differentially regulated by zinc supply in roots and shoots to favour the most highly translated variant under zinc-excess conditions. In A. halleri, a single transcript variant with higher transcript stability and enhanced translation has been maintained. The FRD3 gene thus undergoes complex transcriptional and post-transcriptional regulation in Arabidopsis relatives. Our study reveals that a diverse set of mechanisms underlie increased gene dosage in the A. halleri lineage and illustrates how an environmental challenge can alter gene regulation. PMID:25900619

  9. A Transcriptomic Network Underlies Microstructural and Physiological Responses to Cadmium in Populus × canescens1[C][W

    PubMed Central

    He, Jiali; Li, Hong; Luo, Jie; Ma, Chaofeng; Li, Shaojun; Qu, Long; Gai, Ying; Jiang, Xiangning; Janz, Dennis; Polle, Andrea; Tyree, Melvin; Luo, Zhi-Bin

    2013-01-01

    Bark tissue of Populus × canescens can hyperaccumulate cadmium, but microstructural, transcriptomic, and physiological response mechanisms are poorly understood. Histochemical assays, transmission electron microscopic observations, energy-dispersive x-ray microanalysis, and transcriptomic and physiological analyses have been performed to enhance our understanding of cadmium accumulation and detoxification in P. × canescens. Cadmium was allocated to the phloem of the bark, and subcellular cadmium compartmentalization occurred mainly in vacuoles of phloem cells. Transcripts involved in microstructural alteration, changes in nutrition and primary metabolism, and stimulation of stress responses showed significantly differential expression in the bark of P. × canescens exposed to cadmium. About 48% of the differentially regulated transcripts formed a coregulation network in which 43 hub genes played a central role both in cross talk among distinct biological processes and in coordinating the transcriptomic regulation in the bark of P. × canescens in response to cadmium. The cadmium transcriptome in the bark of P. × canescens was mirrored by physiological readouts. Cadmium accumulation led to decreased total nitrogen, phosphorus, and calcium and increased sulfur in the bark. Cadmium inhibited photosynthesis, resulting in decreased carbohydrate levels. Cadmium induced oxidative stress and antioxidants, including free proline, soluble phenolics, ascorbate, and thiol compounds. These results suggest that orchestrated microstructural, transcriptomic, and physiological regulation may sustain cadmium hyperaccumulation in P. × canescens bark and provide new insights into engineering woody plants for phytoremediation. PMID:23530184

  10. Arsenic-induced responses in Pityrogramma calomelanos (L.) Link: Arsenic speciation, mineral nutrition and antioxidant defenses.

    PubMed

    Campos, N V; Arcanjo-Silva, S; Viana, I B; Batista, B L; Barbosa, F; Loureiro, M E; Ribeiro, C; Azevedo, A A

    2015-12-01

    Arsenic (As) hyperaccumulation trait has been described in a limited number of fern species. The physiological basis of hyperaccumulation remains unclear, especially in non-Pteris species such as Pityrogramma calomelanos. Aiming at a better understanding of As-induced responses, P. calomelanos plants were exposed to 1 mM As for 21 days and compared with control plants. Chemical analyses revealed that As accumulation was ten times higher in pinnae then in roots and stipes. In pinnae, As was present mainly as arsenite, whereas arsenate was the dominant form in stipes and roots. Arsenic promoted an increase in antioxidant enzyme activities in both fern parts and several alterations in mineral nutrition, especially with regard to P and K. A higher content of non-protein thiols was observed in pinnae of plants exposed to As, whereas As induced the increase in lipid peroxidation in roots. The results showed that Pityrogramma calomelanos shares with Pteris vittata several aspects of As metabolism. High root-shoot As translocation showed to be essential to avoid toxic effects in roots, since the root is more sensitive to the metalloid. The higher capacity of P. calomelanos to sequester arsenite in the pinna and its efficient antioxidant system maintain the reactive oxygen species at a low level, thus enhancing the continuous accumulation of As. Molecular investigations are needed to elucidate the evolution of As-tolerance mechanisms in Pteridaceae species, especially with regard to membrane transporters and ROS signaling. PMID:26408808

  11. Interaction between selected bacterial strains and Arabidopsis halleri modulates shoot proteome and cadmium and zinc accumulation

    PubMed Central

    Panigati, Monica; Furini, Antonella

    2011-01-01

    The effects of plant–microbe interactions between the hyperaccumulator Arabidopsis halleri and eight bacterial strains, isolated from the rhizosphere of A. halleri plants grown in a cadmium- and zinc-contaminated site, were analysed for shoot metal accumulation, shoot proteome, and the transcription of genes involved in plant metal homeostasis and hyperaccumulation. Cadmium and zinc concentrations were lower in the shoots of plants cultivated in the presence of these metals plus the selected bacterial strains compared with plants grown solely with these metals or, as previously reported, with plants grown with these metals plus the autochthonous rhizosphere-derived microorganisms. The shoot proteome of plants cultivated in the presence of these selected bacterial strains plus metals, showed an increased abundance of photosynthesis- and abiotic stress-related proteins (e.g. subunits of the photosynthetic complexes, Rubisco, superoxide dismutase, and malate dehydrogenase) counteracted by a decreased amount of plant defence-related proteins (e.g. endochitinases, vegetative storage proteins, and ?-glucosidase). The transcription of several homeostasis genes was modulated by the microbial communities and by Cd and Zn content in the shoot. Altogether these results highlight the importance of plant-microbe interactions in plant protein expression and metal accumulation and emphasize the possibility of exploiting microbial consortia for increasing or decreasing shoot metal content. PMID:21357773

  12. Mechanisms of lichen resistance to metallic pollution

    SciTech Connect

    Sarret, C.; Manceau, A.; Eybert-Berard, L.; Cuny, D.; Haluwyn, C. van; Deruelle, S.; Hazemann, J.L.; Menthonnex, J.J.; Soldo, Y.

    1998-11-01

    Some lichens have a unique ability to grow in heavily contaminated areas due to the development of adaptative mechanisms allowing a high tolerance to metals. Here the authors report on the chemical forms of Pb and Zn in the metal hyperaccumulator Diploschistes muscorum and of Pb in the metal tolerant lichen Xanthoria parietina. The speciation of Zn and Pb has been investigated by powder X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS) spectroscopy using the advanced third-generation synchrotron radiation source of the European synchrotron radiation facility (ESRF in Grenoble). This study reveals that in both lichens cells are protected from toxicity by complexation of heavy metals, but the strategies differ: in D. muscorum, Pb and Zn are accumulated through an enhanced synthesis of oxalate, which precipitates toxic elements as insoluble salts, whereas in X. parietina, Pb is complexed to carboxylic groups of the fungal cell walls. The authors conclude that hyperaccumulation of metals results from a reactive mechanism of organic acid production, whereas metallo-tolerance is achieved by a passive complexation to existing functional groups.

  13. Molecular Genetics of Metal Detoxification: Prospects for Phytoremediation

    SciTech Connect

    Ow, David W. ow@pgec.ams.usda.gov

    2000-09-01

    Unlike compounds that can be broken down, the remediation of most heavy metals and radionuclides requires physical extraction from contaminated sources. Plants can extract inorganics, but effective phytoextraction requires plants that produce high biomass, grow rapidly and possess high capacity-uptake for the inorganic substance. Either hyperaccumulator plants must be bred for increased growth and biomass or hyperaccumulation traits must be engineered into fast growing, high biomass plants. This latter approach requires fundamental knowledge of the molecular mechanisms in the uptake and storage of inorganics. Much has been learned in recent years on how plants and certain fungi chelate and transport selected heavy metals. This progress has been facilitated by the use of Schizosaccharomyces pombe as a model system. The use of a model organism for study permits rapid characterization of the molecular process. As target genes are identified in a model organism, their sequences can be modified for expression in a heterologous host or aid in the search of homologous genes in more complex organisms. Moreover, as plant nutrient uptake is intrinsically linked to the association with rhizospheric fungi, elucidating metal sequestration in this fungus permits additional opportunities for engineering rhizospheric microbes to assist in phytoextraction.

  14. Uptake and Fate of Ethephon ([2-Chloroethyl]phosphonic Acid) in Dormant Weed Seeds 1

    PubMed Central

    Goudey, J. Stephen; Saini, Hargurdeep S.; Spencer, Mary S.

    1987-01-01

    Although ethephon ([2-chloroethyl]phosphonic acid) is often used as a form of liquid ethylene in studies of seed germination, it is not known if ethylene evolved from ethephon in the seed is sufficient to elicit the desired response and/or if ethephon has a regulatory action that alone accounts for the response. For these reasons we studied the uptake and fate of [1,2-14C]ethephon in dormant seeds of Avena fatua, Sinapis arvensis, Thlaspi arvense, and Chenopodium album. The radioactivity within the seeds was separated into a labile carbon-labeled ethephon/ethylene fraction (64-87%) and, following extraction in methanol-chloroform-water (12:5:3), into fractions associated with insoluble (12-29%) and soluble (3-8%) seed constituents. The radioactivity associated with seed constituents was reduced 5 to 75% by hot alkaline hydrolysis (2.5 n KOH, 70° C for 1 hour). Although a small portion of the ethephon (or metabolite of ethephon/ethylene) taken up by the seeds is tightly bound to the tissues, our results indicate that, at the appropriate external concentrations of ethephon, the amount of ethylene evolved from ethephon within the seeds is sufficient to produce the desired ethylene mediated responses. However, factors affecting the decomposition of ethephon must be considered in the decision as to whether to use ethephon as a liquid supply of ethylene. PMID:16665648

  15. Cytological studies of Brassicaceae burn. (Cruciferae juss.) from Western Himalayas.

    PubMed

    Jeelani, S M; Rani, S; Kumar, S; Kumari, S; Gupta, R C

    2013-01-01

    Cytological studies have been carried out on 12 species of Brassicaceae Burn. on population basis from different geographical areas of Kashmir and Himachal Pradesh in the Western Himalayas. Variable chromosome reports for Barbaraea intermedia (n = 16), Cardamine loxostemonoides (n = 8), Nasturtium officinale (n = 8), Sisymbrium orientale (n = 14) on world-wide basis have been added to the previous reports of these species. The chromosome numbers in seven species as Barbaraea intermedia (n = 8), B. vulgaris (n = 8), Capsella bursa-pastoris (n = 8), Descuriania sophia (n = 10), Rorippa islandica (n = 8), Sisymbrium strictum (n = 7) and Thlaspi alpestre (n = 7) have been worked out for the first time from India. The meiotic course in the populations of seven species such as Barbaraea intermedia, Capsella bursa-pastoris, Coronopus didymus, Descuriania sophia, Nasturtium officinale, Sisymbrium orientale and S. strictum varies from normal to abnormal while all the populations of two species Barbaraea vulgaris and Sisymbrium irio show abnormal meiotic course. Meiotic abnormalities are in the form of cytomixis, chromosomal stickiness, unoriented bivalents, inter-bivalent connections, formation of laggards and bridges, all resulting into abnormal microsporogenesis. Heterogenous sized fertile pollen grains and reduced reproductive potentialities have invariably been observed in all the meiotically abnormal populations. However, the meiotic course in all the populations of Cardamine loxostemonoides, Rorippa islandica and Thalspi alpestre is found to be normal with high pollen fertility. PMID:23427609

  16. A comparative study of salt tolerance parameters in 11 wild relatives of Arabidopsis thaliana

    PubMed Central

    Orsini, Francesco; D'Urzo, Matilde Paino; Inan, Gunsu; Serra, Sara; Oh, Dong-Ha; Mickelbart, Michael V.; Consiglio, Federica; Jeong, Jae Cheol; Yun, Dae-Jin; Bohnert, Hans J.; Bressan, Ray A.; Maggio, Albino

    2010-01-01

    Salinity is an abiotic stress that limits both yield and the expansion of agricultural crops to new areas. In the last 20 years our basic understanding of the mechanisms underlying plant tolerance and adaptation to saline environments has greatly improved owing to active development of advanced tools in molecular, genomics, and bioinformatics analyses. However, the full potential of investigative power has not been fully exploited, because the use of halophytes as model systems in plant salt tolerance research is largely neglected. The recent introduction of halophytic Arabidopsis-Relative Model Species (ARMS) has begun to compare and relate several unique genetic resources to the well-developed Arabidopsis model. In a search for candidates to begin to understand, through genetic analyses, the biological bases of salt tolerance, 11 wild relatives of Arabidopsis thaliana were compared: Barbarea verna, Capsella bursa-pastoris, Hirschfeldia incana, Lepidium densiflorum, Malcolmia triloba, Lepidium virginicum, Descurainia pinnata, Sisymbrium officinale, Thellungiella parvula, Thellungiella salsuginea (previously T. halophila), and Thlaspi arvense. Among these species, highly salt-tolerant (L. densiflorum and L. virginicum) and moderately salt-tolerant (M. triloba and H. incana) species were identified. Only T. parvula revealed a true halophytic habitus, comparable to the better studied Thellungiella salsuginea. Major differences in growth, water transport properties, and ion accumulation are observed and discussed to describe the distinctive traits and physiological responses that can now be studied genetically in salt stress research. PMID:20595237

  17. A comparative study of salt tolerance parameters in 11 wild relatives of Arabidopsis thaliana.

    PubMed

    Orsini, Francesco; D'Urzo, Matilde Paino; Inan, Gunsu; Serra, Sara; Oh, Dong-Ha; Mickelbart, Michael V; Consiglio, Federica; Li, Xia; Jeong, Jae Cheol; Yun, Dae-Jin; Bohnert, Hans J; Bressan, Ray A; Maggio, Albino

    2010-08-01

    Salinity is an abiotic stress that limits both yield and the expansion of agricultural crops to new areas. In the last 20 years our basic understanding of the mechanisms underlying plant tolerance and adaptation to saline environments has greatly improved owing to active development of advanced tools in molecular, genomics, and bioinformatics analyses. However, the full potential of investigative power has not been fully exploited, because the use of halophytes as model systems in plant salt tolerance research is largely neglected. The recent introduction of halophytic Arabidopsis-Relative Model Species (ARMS) has begun to compare and relate several unique genetic resources to the well-developed Arabidopsis model. In a search for candidates to begin to understand, through genetic analyses, the biological bases of salt tolerance, 11 wild relatives of Arabidopsis thaliana were compared: Barbarea verna, Capsella bursa-pastoris, Hirschfeldia incana, Lepidium densiflorum, Malcolmia triloba, Lepidium virginicum, Descurainia pinnata, Sisymbrium officinale, Thellungiella parvula, Thellungiella salsuginea (previously T. halophila), and Thlaspi arvense. Among these species, highly salt-tolerant (L. densiflorum and L. virginicum) and moderately salt-tolerant (M. triloba and H. incana) species were identified. Only T. parvula revealed a true halophytic habitus, comparable to the better studied Thellungiella salsuginea. Major differences in growth, water transport properties, and ion accumulation are observed and discussed to describe the distinctive traits and physiological responses that can now be studied genetically in salt stress research. PMID:20595237

  18. Weathering and vegetation controls on nickel isotope fractionation in surface ultramafic environments (Albania)

    NASA Astrophysics Data System (ADS)

    Estrade, Nicolas; Cloquet, Christophe; Echevarria, Guillaume; Sterckeman, Thibault; Deng, Tenghaobo; Tang, YeTao; Morel, Jean-Louis

    2015-08-01

    The dissolved nickel (Ni) isotopic composition of rivers and oceans presents an apparent paradox. Even though rivers represent a major source of Ni in the oceans, seawater is more enriched in the heavier isotopes than river-water. Additional sources or processes must therefore be invoked to account for the isotopic budget of dissolved Ni in seawater. Weathering of continental rocks is thought to play a major role in determining the magnitude and sign of isotopic fractionation of metals between a rock and the dissolved product. We present a study of Ni isotopes in the rock-soil-plant systems of several ultramafic environments. The results reveal key insights into the magnitude and the control of isotopic fractionation during the weathering of continental ultramafic rocks. This study introduces new constraints on the influence of vegetation during the weathering process, which should be taken into account in interpretations of the variability of Ni isotopes in rivers. The study area is located in a temperate climate zone within the ophiolitic belt area of Albania. The serpentinized peridotites sampled present a narrow range of heavy Ni isotopic compositions (?60Ni = 0.25 ± 0.16 ‰, 2SD n = 2). At two locations, horizons within two soil profiles affected by different degrees of weathering all presented light isotopic compositions compared to the parent rock (?60Nisoil-rock up to - 0.63 ‰). This suggests that the soil pool takes up the light isotopes, while the heavier isotopes remain in the dissolved phase. By combining elemental and mineralogical analyses with the isotope compositions determined for the soils, the extent of fractionation was found to be controlled by the secondary minerals formed in the soil. The types of vegetation growing on ultramafic-derived soils are highly adapted and include both Ni-hyperaccumulating species, which can accumulate several percent per weight of Ni, and non-accumulating species. Whole-plant isotopic compositions were found to be isotopically heavier than the soil (?60Niwhole plant-soil up to 0.40‰). Fractions of Ni extracted by DTPA (diethylenetriaminepentaacetic acid) presented isotopically heavy compositions compared to the soil (?60NiDTPA-soil up to 0.89‰), supporting the hypothesis that the dissolved Ni fraction controlled by weathering has a heavy isotope signature. The non-hyperaccumulators (n = 2) were inclined to take up and translocate light Ni isotopes with a large degree of fractionation (?60Nileaves-roots up to - 0.60 ‰). For Ni-hyperaccumulators (n = 7), significant isotopic fractionation was observed in the plants in their early growth stages, while no fractionation occurred during later growth stages, when plants are fully loaded with Ni. This suggests that (i) the high-efficiency translocation process involved in hyperaccumulators does not fractionate Ni isotopes, and (ii) the root uptake process mainly controls the isotopic composition of the plant. In ultramafic contexts, vegetation composed of hyperaccumulators can significantly influence isotopic compositions through its remobilization in the upper soil horizon, thereby influencing the isotopic balance of Ni exported to rivers.

  19. Hormetic Responses of Lonicera Japonica Thunb. To Cadmium Stress

    PubMed Central

    Liu, Zhouli; Chen, Wei; Jia, Lian; Yu, Shuai; Zhao, Mingzhu

    2015-01-01

    The hormetic responses of Lonicera japonica Thunb. to cadmium (Cd) stress were investigated in a hydroponic experiment. The present results showed that root length and total biomass dry weight increased in comparison with the control at low concentrations Cd. The height of the plant exposed to 2.5 and 5 mg L-1 Cd increased significantly by 11.9% and 12.8% relative to the control, and with the increase of Cd concentrations in the medium, plant height began to decrease. The responses of photosynthetic pigments contents and relative water content to Cd stress had a similar trend, which all showed significantly an inverted U-shaped dose–response curve and confirmed that the stimulatory effect of low concentrations Cd occurred in the plant. Furthermore, L. japonica, as a new Cd-hyperaccumulator, could be considered as a new plant model to study the underlying mechanisms of the hormesis. PMID:26672952

  20. The ABC Transporter ABCG1 Is Required for Suberin Formation in Potato Tuber Periderm[W

    PubMed Central

    Landgraf, Ramona; Smolka, Ulrike; Altmann, Simone; Eschen-Lippold, Lennart; Senning, Melanie; Sonnewald, Sophia; Weigel, Benjamin; Frolova, Nadezhda; Strehmel, Nadine; Hause, Gerd; Scheel, Dierk; Böttcher, Christoph; Rosahl, Sabine

    2014-01-01

    The lipid biopolymer suberin plays a major role as a barrier both at plant-environment interfaces and in internal tissues, restricting water and nutrient transport. In potato (Solanum tuberosum), tuber integrity is dependent on suberized periderm. Using microarray analyses, we identified ABCG1, encoding an ABC transporter, as a gene responsive to the pathogen-associated molecular pattern Pep-13. Further analyses revealed that ABCG1 is expressed in roots and tuber periderm, as well as in wounded leaves. Transgenic ABCG1-RNAi potato plants with downregulated expression of ABCG1 display major alterations in both root and tuber morphology, whereas the aerial part of the ABCG1-RNAi plants appear normal. The tuber periderm and root exodermis show reduced suberin staining and disorganized cell layers. Metabolite analyses revealed reduction of esterified suberin components and hyperaccumulation of putative suberin precursors in the tuber periderm of RNA interference plants, suggesting that ABCG1 is required for the export of suberin components. PMID:25122151

  1. Efficiency of repeated phytoextraction of cadmium and zinc from an agricultural soil contaminated with sewage sludge.

    PubMed

    Luo, Kai; Ma, Tingting; Liu, Hongyan; Wu, Longhua; Ren, Jing; Nai, Fengjiao; Li, Rui; Chen, Like; Luo, Yongming; Christie, Peter

    2015-01-01

    Long-term application of sewage sludge resulted in soil cadmium (Cd) and zinc (Zn) contamination in a pot experiment conducted to phytoextract Cd/Zn repeatedly using Sedum plumbizincicola and Apium graceolens in monoculture or intercropping mode eight times. Shoot yields and soil physicochemical properties changed markedly with increasing number of remediation crops when the two plant species were intercropped compared with the unplanted control soil and the two monoculture treatments. Changes in soil microbial indices such as average well colour development, soil enzyme activity and soil microbial counts were also significantly affected by the growth of the remediation plants, especially intercropping with S. plumbizincicola and A. graveolens. The higher yields and amounts of Cd taken up indicated that intercropping of the hyperaccumulator and the vegetable species may be suitable for simultaneous agricultural production and soil remediation, with larger crop yields and higher phytoremediation efficiencies than under monoculture conditions. PMID:25747245

  2. Cotton cytochrome P450 CYP82D regulates systemic cell death by modulating the octadecanoid pathway

    PubMed Central

    Sun, Longqing; Zhu, Longfu; Xu, Li; Yuan, Daojun; Min, Ling; Zhang, Xianlong

    2014-01-01

    Plant oxylipins are derived from unsaturated fatty acids and play roles in plant growth and development as well as defence. Although recent studies have revealed that fatty acid metabolism is involved in systemic acquired resistance, the precise function of oxylipins in plant defence remains unknown. Here we report a cotton P450 gene SILENCE-INDUCED STEM NECROSIS (SSN), RNAi suppression of which causes a lesion mimic phenotype. SSN is also involved in jasmonate metabolism and the response to wounding. Fatty acid and oxylipin metabolite analysis showed that SSN overexpression causes hyperaccumulation of hydroxide and ketodiene fatty acids and reduced levels of 18:2 fatty acids, whereas silencing causes an imbalance in LOX (lipoxygenase) expression and excessive hydroperoxide fatty acid accumulation. We also show that an unknown oxylipin-derived factor is a putative mobile signal required for systemic cell death and hypothesize that SSN acts as a valve to regulate HR on pathogen infection. PMID:25371113

  3. Characterization and multiplexing of 21 microsatellite markers for the herb Noccaea caerulescens (Brassicaceae)1

    PubMed Central

    Mousset, Mathilde; Flaven, Elodie; Justy, Fabienne; Pouzadoux, Juliette; Gode, Cécile; Pauwels, Maxime; Gonneau, Cédric

    2015-01-01

    Premise of the study: Multiplexed microsatellite markers were developed for population genetic studies in the pseudometallophyte Noccaea caerulescens (Brassicaceae), a model species to investigate metal tolerance and hyperaccumulation in higher plants. Methods and Results: Microsatellite loci were isolated through pyrosequencing of an enriched DNA library. Three multiplexes combining four previously published and 17 newly designed markers were developed. The new markers were screened in metallicolous and nonmetallicolous populations from southern France. The total number of alleles per locus ranged from five to 18. The observed heterozygosity per locus and per population ranged from 0 to 0.83, and expected heterozygosity ranged from 0 to 0.89. Conclusions: The investigated loci showed reasonable to high levels of polymorphism at the regional scale. The multiplex set should be helpful in investigating genetic diversity, population structure, and demographic history in N. caerulescens at various spatial scales. PMID:26697274

  4. Reduction of Health Risks Due to Chromium(VI)Using Mesquite: A Potential Cr Phytoremediator

    SciTech Connect

    Gardea-Torresdey, Jorge L.; Aldrich, Mary V.; Peralta-Videa, Jose R.; Parsons, Jason G.

    2004-03-29

    Chromium is a transition metal extensively used in industry. Cr mining and industrial operations account for chromium wastes at Superfund sites in the United States. A study was performed to investigate the possibility of using mesquite (Prosopis spp.), which is an indigenous desert plant species, to remove Cr from contaminated sites. In this study, mesquite plants were grown in an agar-based medium containing 75 mg L-1 and 125 mg L-1 of Cr(VI). The Cr content of leaf tissue (992 mg kg-1 of dry weight, from 125 mg L-1 of Cr(VI)) indicated that mesquite could be classified as a chromium hyperaccumulator. X-ray absorption spectroscopy (XAS) studies performed to experimental samples showed that mesquite roots absorbed some of the supplied Cr(VI). However, the data analyses of plant tissues demonstrated that the absorbed Cr(VI) was fully reduced to Cr(III) in the leaf tissue.

  5. Tolerance of Portulaca grandiflora to individual and combined application of Ni, Pb and Zn.

    PubMed

    Mihailovic, N; Andreji?, G; Dželetovi?, Ž

    2015-01-01

    In the present study, metal accumulation capacity and tolerance of Portulaca grandiflora were investigated. Plants were grown under greenhouse conditions in pots on soil amended with Ni, Pb and Zn to the final concentration of 2 mmol kg(-1) for each metal. Results show considerable accumulating capacity and translocation of Ni and Zn, as well as significant accumulation of Pb in roots. A slight decrease of biomass with Zn and of chlorophyll content with Zn and Ni were observed, as well as an increase of proline content with each of the metals. Combinations of metals revealed mutual interference affecting both the uptake and translocation of the metals and their impact on physiological parameters. Results suggest that Portulaca grandiflora, although not a hyperaccumulator, shows a good tolerance and accumulation capacity for Ni, Pb and Zn, but, for the purposes of remediation, interference of the metals must be taken into account. PMID:25376966

  6. Cotton cytochrome P450 CYP82D regulates systemic cell death by modulating the octadecanoid pathway.

    PubMed

    Sun, Longqing; Zhu, Longfu; Xu, Li; Yuan, Daojun; Min, Ling; Zhang, Xianlong

    2014-01-01

    Plant oxylipins are derived from unsaturated fatty acids and play roles in plant growth and development as well as defence. Although recent studies have revealed that fatty acid metabolism is involved in systemic acquired resistance, the precise function of oxylipins in plant defence remains unknown. Here we report a cotton P450 gene SILENCE-INDUCED STEM NECROSIS (SSN), RNAi suppression of which causes a lesion mimic phenotype. SSN is also involved in jasmonate metabolism and the response to wounding. Fatty acid and oxylipin metabolite analysis showed that SSN overexpression causes hyperaccumulation of hydroxide and ketodiene fatty acids and reduced levels of 18:2 fatty acids, whereas silencing causes an imbalance in LOX (lipoxygenase) expression and excessive hydroperoxide fatty acid accumulation. We also show that an unknown oxylipin-derived factor is a putative mobile signal required for systemic cell death and hypothesize that SSN acts as a valve to regulate HR on pathogen infection. PMID:25371113

  7. Combined toxicity of mercury and plastic wastes to crustacean and gastropod inhabiting the waters in Kuwait.

    PubMed

    Bu-Olayan, A H; Thomas, B V

    2015-11-01

    The present study determined total mercury (T-Hg) in crustacean Portunus pelagicus (blue crab) and mollusc Tapes sulcarius (Furrowed Venus: Cockle) following suspected rise in beach plastic wastes and their effect on marine organisms. Live samples were collected from beaches representing six Kuwait Governorate areas and exposed to toxicity (96hr) and bio accumulation tests for 180 d with inclusion of plastic wastes and environmental conditions simulated in laboratory. Results revealed high T-Hg concentrations in T sulcarius (1.44ng l(-1)) compared to P. pelagicus (1.03ng l(-1)) during winter than summer, with bio accumulation factor (BAF) > 1 labelled these species as hyper-accumulators. Significantly, combination of T-Hg concentrations from plastic wastes and in seawater validated the possibilities of detrimental effects of other marine lives besides deteriorating the aesthetic values of scenic beaches and likelihood of invasive species in such coastal areas. PMID:26688963

  8. Silicon in Imperata cylindrica (L.) P. Beauv: content, distribution, and ultrastructure.

    PubMed

    Rufo, Lourdes; Franco, Alejandro; de la Fuente, Vicenta

    2014-07-01

    Silicon concentration, distribution, and ultrastructure of silicon deposits in the Poaceae Imperata cylindrica (L.) P. Beauv. have been studied. This grass, known for its medicinal uses and also for Fe hyperaccumulation and biomineralization capacities, showed a concentration of silicon of 13,705 ± 9,607 mg/kg dry weight. Silicon was found as an important constituent of cell walls of the epidermis of the whole plant. Silica deposits were found in silica bodies, endodermis, and different cells with silicon-collapsed lumen as bulliforms, cortical, and sclerenchyma cells. Transmission electron microscope observations of these deposits revealed an amorphous material of an ultrastructure similar to that previously reported in silica bodies of other Poaceae. PMID:24337803

  9. Phytoremediation potential of Cd and Zn by wetland plants, Colocasia esculenta L. Schott., Cyperus malaccensis Lam. and Typha angustifolia L. grown in hydroponics.

    PubMed

    Chayapan, P; Kruatrachue, M; Meetam, M; Pokethitiyook, P

    2015-09-01

    Cadmium and zinc phytoremediation potential of wetland plants, Colocasia esculenta, Cyperus malaccensis, and Typha angustifolia, was investigated. Plants were grown for 15 days in nutrient solutions containing various concentrations of Cd (0, 5, 10, 20, 50 mg l(-1)) and Zn (0, 10, 20, 50, 100 mg l(-1)). T angustifolia was tolerant to both metals as indicated by high RGR when grown in 50 mg I(-1) Cd and 100 mg I(-1) Zn solutions. All these plants accumulated more metals in their underground parts and > 100 mg kg(-1) in their aboveground with TF values < 1. Only C. esculenta could be considered a Zn hyperaccumulator because it could concentrate > 10,000 mg kg(-1) in its aboveground parts with TF > 1. T angustifolia exhibited highest biomass production and highest Cd and Zn uptake, confirming that this plant is a suitable candidate for treating of Cd contaminated soil/sediments. PMID:26521563

  10. Effect of lead on root growth

    PubMed Central

    Fahr, Mouna; Laplaze, Laurent; Bendaou, Najib; Hocher, Valerie; Mzibri, Mohamed El; Bogusz, Didier; Smouni, Abdelaziz

    2013-01-01

    Lead (Pb) is one of the most widespread heavy metal contaminant in soils. It is highly toxic to living organisms. Pb has no biological function but can cause morphological, physiological, and biochemical dysfunctions in plants. Plants have developed a wide range of tolerance mechanisms that are activated in response to Pb exposure. Pb affects plants primarily through their root systems. Plant roots rapidly respond either (i) by the synthesis and deposition of callose, creating a barrier that stops Pb entering (ii) through the uptake of large amounts of Pb and its sequestration in the vacuole accompanied by changes in root growth and branching pattern or (iii) by its translocation to the aboveground parts of plant in the case of hyperaccumulators plants. Here we review the interactions of roots with the presence of Pb in the rhizosphere and the effect of Pb on the physiological and biochemical mechanisms of root development. PMID:23750165

  11. Regulation of Starch Stores by a Ca(2+)-Dependent Protein Kinase Is Essential for Viable Cyst Development in Toxoplasma gondii.

    PubMed

    Uboldi, Alessandro D; McCoy, James M; Blume, Martin; Gerlic, Motti; Ferguson, David J P; Dagley, Laura F; Beahan, Cherie T; Stapleton, David I; Gooley, Paul R; Bacic, Antony; Masters, Seth L; Webb, Andrew I; McConville, Malcolm J; Tonkin, Christopher J

    2015-12-01

    Transmissible stages of Toxoplasma gondii store energy in the form of the carbohydrate amylopectin. Here, we show that the Ca(2+)-dependent protein kinase CDPK2 is a critical regulator of amylopectin metabolism. Increased synthesis and loss of degradation of amylopectin in CDPK2 deficient parasites results in the hyperaccumulation of this sugar polymer. A carbohydrate-binding module 20 (CBM20) targets CDPK2 to amylopectin stores, while the EF-hands regulate CDPK2 kinase activity in response to Ca(2+) to modulate amylopectin levels. We identify enzymes involved in amylopectin turnover whose phosphorylation is dependent on CDPK2 activity. Strikingly, accumulation of massive amylopectin granules in CDPK2-deficient bradyzoite stages leads to gross morphological defects and complete ablation of cyst formation in a mouse model. Together these data show that Ca(2+) signaling regulates carbohydrate metabolism in Toxoplasma and that the post-translational control of this pathway is required for normal cyst development. PMID:26651943

  12. Aquatic zooremediation: deploying animals to remediate contaminated aquatic environments.

    PubMed

    Gifford, Scott; Dunstan, R Hugh; O'Connor, Wayne; Koller, Claudia E; MacFarlane, Geoff R

    2007-02-01

    The ability of animals to act in a bioremediative capacity is not widely known. Animals are rarely considered for bioremediation initiatives owing to ethical or human health concerns. Nonetheless, specific examples in the literature reveal that some animal species are effective remediators of heavy metals, microbial contaminants, hydrocarbons, nutrients and persistent organic pollutants, particularly in an aquatic environment. Recent examples include deploying pearl oysters to remove metals and nutrients from aquatic ecosystems and the harvest of fish to remove polychlorinated biphenyls (PCBs) from the Baltic. It is probable that many animal taxa will possess attributes amenable to bioremediation. We introduce zoological equivalents of the definitions used in phytoremediation literature (zooextraction, zootransformation, zoostabilization and animal hyperaccumulation), to serve as useful benchmarks in the evaluation of candidate animal species for zooremediation initiatives, and propose that recognition of the concept of zooremediation would act to stimulate discussion and future research in this area. PMID:17173992

  13. Phytoremediation of Ionic and Methyl Mercury Pollution

    SciTech Connect

    Meagher, Richard B.

    2005-06-01

    Phytoremediation is defined as the use of plants to extract, resist, detoxify, and/or sequester toxic environmental pollutants. The long-term goal of the proposed research is to develop and test highly productive, field-adapted plant species that have been engineered for the phytoremediation of mercury. A variety of different genes, which should enable plants to clean mercury polluted sites are being tested as tools for mercury phytoremediation, first in model laboratory plants and then in potential field species. Several of these genes have already been shown to enhance mercury phytoremediation. Mercury pollution is a serious, world-wide problem affecting the health of human and wildlife populations. Environmentally, the most serious mercury threat is the production of methylmercury (CH3Hg+) by native bacteria at mercury contaminated wetland sites. Methylmercury is inherently more toxic than metallic (Hg(0)) or ionic (Hg(II)) mercury, and because methylmercury is prolifically biomagnified up the food chain, it poses the most immediate danger to animal populations. We have successfully engineered two model plants, Arabidopsis and tobacco, to use the bacterial merB gene to convert methylmercury to less toxic ionic mercury and to use the bacterial merA gene to further detoxify ionic mercury to the least toxic form of mercury, metallic mercury. Plants expressing both MerA and MerB proteins detoxify methylmercury in two steps to the metallic form. These plants germinate, grow, and set seed at normal growth rates on levels of methylmercury or ionic mercury that are lethal to normal plants. Our newest efforts involve engineering plants with several additional bacterial and plant genes that allow for higher levels of mercury resistance and mercury hyperaccumulation. The potential for these plants to hyperaccumulate mercury was further advanced by developing constitutive, aboveground, and root-specific gene expression systems. Our current strategy is to engineer plants to control the chemical speciation, electrochemical state, transport, and aboveground binding of mercury in order to manage this toxicant. To advance this mercury phytoremediation strategy, our planned research focuses on the following Specific Aims: (1) to increase the transport of mercury to aboveground tissue; (2) to identify small mercury binding peptides that enhance hyperaccumulation aboveground; (3) to test the ability of multiple genes acting together to enhance resistance and hyperaccumulation; (4) to construct a simple molecular system for creating male/female sterility, allowing engineered grass, shrub, and tree species to be released indefinitely at contaminated sites; (5) to test the ability of transgenic cottonwood and rice plants to detoxify ionic mercury and prevent methylmercury release from contaminated sediment; and (6) to initiate field testing with transgenic cottonwood and rice for the remediation of methylmercury and ionic mercury. The results of these experiments will enable the phytoremediation of methyl- and ionic mercury by a wide spectrum of deep-rooted, fast-growing plants adapted to diverse environments. We have made significant progress on all six of these specific aims as summarized below.

  14. Nitrates and Glucosinolates as Strong Determinants of the Nutritional Quality in Rocket Leafy Salads

    PubMed Central

    Cavaiuolo, Marina; Ferrante, Antonio

    2014-01-01

    Rocket is an important leafy vegetable crop and a good source of antioxidants and anticancer molecules such as glucosinolates and other sulfur compounds. Rocket is also a hyper-accumulator of nitrates which have been considered for long time the main factors that cause gastro-intestinal cancer. In this review, the content of these compounds in rocket tissues and their levels at harvest and during storage are discussed. Moreover, the effect of these compounds in preventing or inducing human diseases is also highlighted. This review provides an update to all the most recent studies carried out on rocket encouraging the consumption of this leafy vegetable to reduce the risk of contracting cancer and other cardiovascular diseases. PMID:24736897

  15. Repressor-mediated tissue-specific gene expression in plants

    DOEpatents

    Meagher, Richard B. (Athens, GA); Balish, Rebecca S. (Oxford, OH); Tehryung, Kim (Athens, GA); McKinney, Elizabeth C. (Athens, GA)

    2009-02-17

    Plant tissue specific gene expression by way of repressor-operator complexes, has enabled outcomes including, without limitation, male sterility and engineered plants having root-specific gene expression of relevant proteins to clean environmental pollutants from soil and water. A mercury hyperaccumulation strategy requires that mercuric ion reductase coding sequence is strongly expressed. The actin promoter vector, A2pot, engineered to contain bacterial lac operator sequences, directed strong expression in all plant vegetative organs and tissues. In contrast, the expression from the A2pot construct was restricted primarily to root tissues when a modified bacterial repressor (LacIn) was coexpressed from the light-regulated rubisco small subunit promoter in above-ground tissues. Also provided are analogous repressor operator complexes for selective expression in other plant tissues, for example, to produce male sterile plants.

  16. Polycyclic aromatic hydrocarbons in soils and lower-layer plants of the southern shrub tundra under technogenic conditions

    NASA Astrophysics Data System (ADS)

    Yakovleva, E. V.; Gabov, D. N.; Beznosikov, V. A.; Kondratenok, B. M.

    2014-06-01

    In soils and plants of the southern shrub tundra, 15 polycyclic aromatic hydrocarbons (PAHs) have been detected by high-performance liquid chromatography. Polyarenes in emissions, soil organic horizons, and plants mainly include low-molecular-weight PAHs: naphthalene, fluorine, and pyrene. The contents of the total PAHs in soils and plants exceed the background levels by 3-5 times. The distribution of polyarenes among the organs of the studied plants is nonuniform and depends on the plant species and technogenic load on the area. The studied plants include both hyperaccumulators of polyarenes ( Pleurozium schreberi) and indicators of PAHs in the soil ( Polytrichum commune). Pleurozium schreberi is the most abundant species in the areas under study, and it accumulates the largest mass fraction of PAHs. The differences in the accumulation of PAHs by the plants of the tundra and taiga zones have been revealed.

  17. Literature review: Phytoaccumulation of chromium, uranium, and plutonium in plant systems

    SciTech Connect

    Hossner, L.R.; Loeppert, R.H.; Newton, R.J.; Szaniszlo, P.J.

    1998-05-01

    Phytoremediation is an integrated multidisciplinary approach to the cleanup of contaminated soils, which combines the disciplines of plant physiology, soil chemistry, and soil microbiology. Metal hyperaccumulator plants are attracting increasing attention because of their potential application in decontamination of metal-polluted soils. Traditional engineering technologies may be too expensive for the remediation of most sites. Removal of metals from these soils using accumulator plants is the goal of phytoremediation. The emphasis of this review has been placed on chromium (Cr), plutonium (Pu), and uranium (U). With the exception of Cr, these metals and their decay products exhibit two problems, specifically, radiation dose hazards and their chemical toxicity. The radiation hazard introduces the need for special precautions in reclamation beyond that associated with non-radioactive metals. The uptake of beneficial metals by plants occurs predominantly by way of channels, pores, and transporters in the root plasma membrane. Plants characteristically exhibit a remarkable capacity to absorb what they need and exclude what they don`t need. But most vascular plants absorb toxic and heavy metals through their roots to some extent, though to varying degrees, from negligible to substantial. Sometimes absorption occurs because of the chemical similarity between beneficial and toxic metals. Some plants utilize exclusion mechanisms, where there is a reduced uptake by the roots or a restricted transport of the metal from root to shoot. At the other extreme, hyperaccumulator plants absorb and concentrate metals in both roots and shoots. Some plant species endemic to metalliferous soils accumulate metals in percent concentrations in the leaf dry matter.

  18. Orchestration of three transporters and distinct vascular structures in node for intervascular transfer of silicon in rice.

    PubMed

    Yamaji, Naoki; Sakurai, Gen; Mitani-Ueno, Namiki; Ma, Jian Feng

    2015-09-01

    Requirement of mineral elements in different plant tissues is not often consistent with their transpiration rate; therefore, plants have developed systems for preferential distribution of mineral elements to the developing tissues with low transpiration. Here we took silicon (Si) as an example and revealed an efficient system for preferential distribution of Si in the node of rice (Oryza sativa). Rice is able to accumulate more than 10% Si of the dry weight in the husk, which is required for protecting the grains from water loss and pathogen infection. However, it has been unknown for a long time how this hyperaccumulation is achieved. We found that three transporters (Lsi2, Lsi3, and Lsi6) located at the node are involved in the intervascular transfer, which is required for the preferential distribution of Si. Lsi2 was polarly localized to the bundle sheath cell layer around the enlarged vascular bundles, which is next to the xylem transfer cell layer where Lsi6 is localized. Lsi3 was located in the parenchyma tissues between enlarged vascular bundles and diffuse vascular bundles. Similar to Lsi6, knockout of Lsi2 and Lsi3 also resulted in decreased distribution of Si to the panicles but increased Si to the flag leaf. Furthermore, we constructed a mathematical model for Si distribution and revealed that in addition to cooperation of three transporters, an apoplastic barrier localized at the bundle sheath cells and development of the enlarged vascular bundles in node are also required for the hyperaccumulation of Si in rice husk. PMID:26283388

  19. Increased lead availability and enzyme activities in root-adhering soil of Lantana camara during phytoextraction in the presence of earthworms.

    PubMed

    Jusselme, My Dung; Miambi, Edouard; Mora, Philippe; Diouf, Michel; Rouland-Lefèvre, Corinne

    2013-02-15

    Earthworms are known to increase availability of heavy metals in soils and also play an important role in maintaining the structure and quality of soil. The introduction of earthworms into soils contaminated with metals in the presence of a potential hyperaccumulator has been suggested as an aid for phytoremediation processes. The present study was conducted to evaluate: (i) the effects of earthworms on lead availability in artificially contaminated soil at 500 and 1000 mg kg(-1) Pb in the presence of Lantana camara, a hyperaccumulator, (ii) the effects of earthworms and lead on soil properties such as pH, cation exchange capacity (CEC), organic matter (OM), total and available N, P and K and (iii) soil enzyme activities. Earthworms increased the bioavailable Pb in root-adhering soil by a factor of 2 to 3 in the contaminated soils at concentrations of 500 to 1000 mg Pb kg(-1), respectively. In lead contaminated soils, the presence of earthworms led to a significant decrease in soil pH by about 0.2 but increased CEC by 17% and OM by more than 30%. Earthworm activities also increased the activities of N-acetylglucosamidase, ?-glucosidase, cellulase, xylanase, alkaline and acid phosphatase, urease and fluorescein diacetate assay (FDA). These results indicate that the ecological context for phytoremediation should be broadened by considering plant-soil-earthworm interactions as they influence both plant health and absorption of heavy metals. They also showed that the enzyme activities monitored could serve as useful proxies for phytoremediation capability and, more generally, for soil quality as a whole. PMID:23321070

  20. Arsenic speciation in tissues of the hyperacumulator P. calomelanos var. austroamericana using x-ray absorption spectroscopy.

    SciTech Connect

    Heald, S. M.; Kachenko, A.; Graefe, M.; Singh, B.; X-Ray Science Division; Univ. of Sydney

    2010-06-15

    The fate and chemical speciation of arsenic (As) uptake, translocation and storage by the As hyperaccumulating fern Pityogramma calomelanos var. austroamericana (Pteridaceae) were examined using inductively coupled plasma-atomic emission spectrometry (ICP-AES) and synchrotron-based {mu}-X-ray absorption near edge structure ({mu}-XANES) and {mu}-X-ray fluorescence ({mu}-XRF) spectroscopies. Chemical analysis revealed total As concentration was ca. 6.5 times greater in young fronds (5845 mg kg {sup -1} dry weight) than in old frons (903 mg kg {sup -1} DW) pinnae, As concentration decreased from the base (6822 mg kg {sup -1} DW) to the apex (4301 mg kg {sup -1}DW) of the fronds. The results from {mu}-XANES and {mu}-XRF of living tissues suggested that more than 60% of arsenate (As{sup v}) absorbed was reduced to arsenite (As{sup III}) in roots, prior to transport through vascular tissues as As{sup v} and As{sup III}. In pinnules, As{sup III} was the predominate redox species (72-90%), presumably as solvated, oxygen coordinated compounds. The presence of putative As{sup III}-sulphide (S{sup -2}) coordinationthroughout the fern tissues (4-25%) suggests that S{sup 2-} functional groups may contribute in the biochemical reduction of As{sup v} to As{sup III} during uptake and transport at a whole plant level. Organic arsenicals and thiol-rich compounds were not detected in the species and are unlikely to play a role in As hyperaccumulation in this fern. The study provides important insights into homeostatic regulation of As following As uptake in P. calomelanos var. austroamericana.

  1. Testing the joint effects hypothesis of elemental defense using Spodoptera exigua.

    PubMed

    Cheruiyot, Dorothy J; Boyd, Robert S; Moar, William

    2015-02-01

    Metal hyperaccumulation may be an elemental defense, in which high concentrations of a metal in plant tissues decrease herbivore survival or growth rate. The Joint Effects Hypothesis suggests that a combination of metals, or a combination of a metal with an organic compound, may have an enhanced defensive effect. The enhancement may be additive or synergistic: in either case the concentration of a particular metal necessary to provide a defensive benefit for the plant is lowered. We tested the Joint Effects Hypothesis using Spodoptera exigua (beet armyworm) neonates fed artificial diets. Metal?+?metal experiments utilized diets amended with metal pairs, using four metals commonly hyperaccumulated by plants (Co, Cu, Ni, and Zn). We also conducted metal?+?organic compound experiments, pairing each metal with nicotine, mustard seed powder, or tannic acid. We tested for joint effects using both lethal (LC20 levels) and sublethal concentrations (10-25 % reduced larval weight) of the chemicals tested. For all experiments, either additive or synergistic effects were found. Of the metal?+?metal pairs tested, three (Co?+?Cu, Cu?+?Zn, and Ni?+?Zn) were synergistic in lethal concentration tests and only Co?+?Cu was synergistic in sublethal tests. For metal?+?organic combination lethal tests, synergism occurred for all combinations except for Co or Ni?+?nicotine, Ni?+?mustard seed powder, and Zn?+?nicotine. For sublethal tests, Zn?+?all three organic chemicals, Co?+?mustard seed powder or tannic acid, and Cu?+?nicotine, were synergistic. These results support the Joint Effects Hypothesis, suggesting that metals combined with other metals or organic compounds may be more effective against herbivores than individual metals. PMID:25712748

  2. Phytoremediation of Ionic and Methyl Mercury Pollution

    SciTech Connect

    Meagher, Richard B.

    2004-12-01

    Phytoremediation is defined as the use of plants to extract, resist, detoxify, and/or sequester toxic environmental pollutants. The long-term goal of the proposed research is to develop and test highly productive, field-adapted plant species that have been engineered for the phytoremediation of mercury. A variety of different genes, which should enable plants to clean mercury polluted sites are being tested as tools for mercury phytoremediation, first in model laboratory plants and then in potential field species. Several of these genes have already been shown to enhance mercury phytoremediation. Mercury pollution is a serious, world-wide problem affecting the health of human and wildlife populations. Environmentally, the most serious mercury threat is the production of methylmercury (CH3Hg+) by native bacteria at mercury contaminated wetland sites. Methylmercury is inherently more toxic than metallic (Hg(0)) or ionic (Hg(II)) mercury, and because methylmercury is prolifically biomagnified up the food chain, it poses the most immediate danger to animal populations. We have successfully engineered two model plants, Arabidopsis and tobacco, to use the bacterial merB gene to convert methylmercury to less toxic ionic mercury and to use the bacterial merA gene to further detoxify ionic mercury to the least toxic form of mercury, metallic mercury. Plants expressing both MerA and MerB proteins detoxify methylmercury in two steps to the metallic form. These plants germinate, grow, and set seed at normal growth rates on levels of methylmercury or ionic mercury that are lethal to normal plants. Our newest efforts involve engineering plants with several additional bacterial and plant genes that allow for higher levels of mercury resistance and mercury hyperaccumulation. The potential for these plants to hyperaccumulate mercury was further advanced by developing constitutive, aboveground, and root-specific gene expression systems.

  3. Phytoremediation of Ionic and Methyl Mercury Pollution

    SciTech Connect

    Meagher, Richard B.

    2005-06-01

    Phytoremediation is defined as the use of plants to extract, resist, detoxify, and/or sequester toxic environmental pollutants. The long-term goal of the proposed research is to develop and test highly productive, field-adapted plant species that have been engineered for the phytoremediation of mercury. A variety of different genes, which should enable plants to clean mercury polluted sites are being tested as tools for mercury phytoremediation, first in model laboratory plants and then in potential field species. Several of these genes have already been shown to enhance mercury phytoremediation. Mercury pollution is a serious, world-wide problem affecting the health of human and wildlife populations. Environmentally, the most serious mercury threat is the production of methylmercury (CH3Hg+) by native bacteria at mercury contaminated wetland sites. Methylmercury is inherently more toxic than metallic (Hg(0)) or ionic (Hg(II)) mercury, and because methylmercury is prolifically biomagnified up the food chain, it poses the most immediate danger to animal populations. We have successfully engineered two model plants, Arabidopsis and tobacco, to use the bacterial merB gene to convert methylmercury to less toxic ionic mercury and to use the bacterial merA gene to further detoxify ionic mercury to the least toxic form of mercury, metallic mercury. Plants expressing both MerA and MerB proteins detoxify methylmercury in two steps to the metallic form. These plants germinate, grow, and set seed at normal growth rates on levels of methylmercury or ionic mercury that are lethal to normal plants. Our newest efforts involve engineering plants with several additional bacterial and plant genes that allow for higher levels of mercury resistance and mercury hyperaccumulation. The potential for these plants to hyperaccumulate mercury was further advanced by developing constitutive, aboveground, and root-specific gene expression systems. Our current strategy is to engineer plants to control the chemical speciation, electrochemical state, transport, and aboveground binding of mercury in order to manage this toxicant.

  4. Evaluation of three endemic Mediterranean plant species Atriplex halimus, Medicago lupulina and Portulaca oleracea for Phytoremediation of Ni, Pb and Zn

    NASA Astrophysics Data System (ADS)

    Chami, Ziad Al; Amer, Nasser; Bitar, Lina Al; Mondelli, Donato; Dumontet, Stefano

    2013-04-01

    The success of phytoremediation depends upon the identification of suitable plants species that hyperaccumulate/tolerate heavy metals and produce large amounts of biomass. In this study, three endemic Mediterranean plant species Atriplex halimus, Medicago lupulina and Portulaca oleracea, were grown hydroponically to assess their potential use in phytoremediation of Ni, Pb and Zn and biomass production. The objective of this research is to improve phytoremediation procedures by searching for a new endemic Mediterranean plant species which can be used for phytoremediation of low/moderate contamination in the Mediterranean arid and semiarid conditions and bioenergy production. The hydroponics experiment was carried out in a growth chamber using half strength Hoagland's solution as control (CTR) and 5 concentrations for Pb and Zn (5, 10, 25, 50 and 100 mg L-1) and 3 concentrations for Ni (1, 2, and 5 mg L-1). Complete randomized design with five replications was adopted. Main growth parameters (shoot and root dry weight, shoot and root length and chlorophyll content) were determined. Shoots and roots were analyzed for their metals contents. Some interesting contributions of this research are: (i) plant metal uptake efficiency ranked as follows: A. halimus > M. lupulina > P. oleracea, whereas heavy metal toxicity ranked as follows: Ni > Zn > Pb, (ii) none of the plant species was identified as hyperaccumulator, (iii) Atriplex halimus and Medicago lupulina can accumulate Ni, Pb and Zn in their roots, (iv) translocate small fraction to their above ground biomass, and (v) indicate moderate pollution levels of the environment. In addition, as they are a good biomass producer, they can be used in phytostabilisation of marginal lands and their above ground biomass can be used for livestock feeding as well for bioenergy production.

  5. Improvement in phytoremediation potential of Solanum nigrum under cadmium contamination through endophytic-assisted Serratia sp. RSC-14 inoculation.

    PubMed

    Khan, Abdur Rahim; Ullah, Ihsan; Khan, Abdul Latif; Park, Gun-Seok; Waqas, Muhammad; Hong, Sung-Jun; Jung, Byung Kwon; Kwak, Yunyoung; Lee, In-Jung; Shin, Jae-Ho

    2015-09-01

    The growth of hyperaccumulator plants is often compromised by increased toxicity of metals like cadmium (Cd). However, extraction of such metals from the soil can be enhanced by endophytic microbial association. Present study was aimed to elucidate the potential of microbe-assisted Cd phytoextraction in hyperaccumulator Solanum nigrum plants and their interactions under varied Cd concentrations. An endophytic bacteria Serratia sp. RSC-14 was isolated from the roots of S. nigrum. In addition to Cd tolerance up to 4 mM, the RSC-14 exhibited phosphate solubilization and secreted plant growth-promoting phytohormones such as indole-3-acetic acid (54 ?g/mL). S. nigrum plants were inoculated with RSC-14 and were grown in different concentrations of Cd (0, 10, and 30 mg Cd kg(-1) sand). Results revealed that Cd treatment caused significant cessation in plant growth, biomass, and chlorophyll content, whereas significantly higher malondialdehyde (MDA) and electrolyte production in leaves were observed in a dose-dependent manner. Conversely, RSC-14 inoculation relived the toxic effects of Cd-induced stress by significantly increasing root/shoot growth, biomass production, and chlorophyll content and decreasing MDA and electrolytes contents. Ameliorative effects on host growth were also observed by the regulation of metal-induced oxidative stress enzymes such as catalase, peroxidase, and polyphenol peroxidase. Activities of these enzymes were significantly reduced in RSC-14 inoculated plants as compared to control plants under Cd treatments. The lower activities of stress responsive enzymes suggest modulation of Cd stress by RSC-14. The current findings support the beneficial uses of Serratia sp. RSC-14 in improving the phytoextraction abilities of S. nigrum plants in Cd contamination. PMID:25956518

  6. Growth and Cadmium Phytoextraction by Swiss Chard, Maize, Rice, Noccaea caerulescens, and Alyssum murale in Ph Adjusted Biosolids Amended Soils.

    PubMed

    Broadhurst, C Leigh; Chaney, Rufus L; Davis, Allen P; Cox, Albert; Kumar, Kuldip; Reeves, Roger D; Green, Carrie E

    2015-01-01

    Past applications of biosolids to soils at some locations added higher Cd levels than presently permitted. Cadmium phytoextraction would alleviate current land use constraints. Unamended farm soil, and biosolids amended farm and mine soils were obtained from a Fulton Co., IL biosolids management facility. Soils contained 0.16, 22.8, 45.3 mg Cd kg(-1) and 43.1, 482, 812 mg Zn kg(-1) respectively with initial pH 6.0, 6.1, 6.4. In greenhouse studies, Swiss chard (Beta vulgaris var. cicla), a Cd-accumulator maize (inbred B37 Zea mays) and a southern France Cd-hyperaccumulator genotype of Noccaea caerulescens were tested for Cd accumulation and phytoextraction. Soil pH was adjusted from ?5.5-7.0. Additionally 100 rice (Oryza sativa) genotypes and the Ni-hyperaccumulator Alyssum murale were screened for potential phytoextraction use. Chard suffered phytotoxicity at low pH and accumulated up to 90 mg Cd kg(-1) on the biosolids amended mine soil. The maize inbred accumulated up to 45 mg Cd kg(-1) with only mild phytotoxicity symptoms during early growth at pH>6.0. N. caerulescens did not exhibit phytotoxicity symptoms at any pH, and accumulated up to 235 mg Cd kg(-1) in 3 months. Reharvested N. caerulescens accumulated up to 900 mg Cd kg(-1) after 10 months. Neither Alyssum nor 90% of rice genotypes survived acceptably. Both N. caerulescens and B37 maize show promise for Cd phytoextraction in IL and require field evaluation; both plants could be utilized for nearly continuous Cd removal. Other maize inbreds may offer higher Cd phytoextraction at lower pH, and mono-cross hybrids higher shoot biomass yields. Further, maize grown only for biomass Cd maximum removal could be double-cropped. PMID:25174422

  7. Effects of Metal Phytoextraction Practices on the Indigenous Community of Arbuscular Mycorrhizal Fungi at a Metal-Contaminated Landfill

    PubMed Central

    Pawlowska, Teresa E.; Chaney, Rufus L.; Chin, Mel; Charvat, Iris

    2000-01-01

    Phytoextraction involves use of plants to remove toxic metals from soil. We examined the effects of phytoextraction practices with three plant species (Silene vulgaris, Thlaspi caerulescens, and Zea mays) and a factorial variation of soil amendments (either an ammonium or nitrate source of nitrogen and the presence or absence of an elemental sulfur supplement) on arbuscular mycorrhizal (AM) fungi (Glomales, Zygomycetes) at a moderately metal-contaminated landfill located in St. Paul, Minn. Specifically, we tested whether the applied treatments affected the density of glomalean spores and AM root colonization in maize. Glomalean fungi from the landfill were grouped into two morphotypes characterized by either light-colored spores (LCS) or dark-colored spores (DCS). Dominant species of the LCS morphotype were Glomus mosseae and an unidentified Glomus sp., whereas the DCS morphotype was dominated by Glomus constrictum. The density of spores of the LCS morphotype from the phytoremediated area was lower than the density of these spores in the untreated landfill soil. Within the experimental area, spore density of the LCS morphotype in the rhizosphere of mycorrhizal maize was significantly higher than in rhizospheres of nonmycorrhizal S. vulgaris or T. caerulescens. Sulfur supplement increased vesicular root colonization in maize and exerted a negative effect on spore density in maize rhizosphere. We conclude that phytoextraction practices, e.g., the choice of plant species and soil amendments, may have a great impact on the quantity and species composition of glomalean propagules as well as on mycorrhiza functioning during long-term metal-remediation treatments. PMID:10831433

  8. A Phytoremediation Strategy for Arsenic

    SciTech Connect

    Meagher, Richard B.

    2005-06-01

    A Phytoremediation Strategy for Arsenic Progress Report May, 2005 Richard B. Meagher Principal Investigator Arsenic pollution affects the health of several hundred millions of people world wide, and an estimated 10 million Americans have unsafe levels of arsenic in their drinking water. However, few environmentally sound remedies for cleaning up arsenic contaminated soil and water have been proposed. Phytoremediation, the use of plants to extract and sequester environmental pollutants, is one new technology that offers an ecologically sound solution to a devastating problem. We propose that it is less disruptive to the environment to harvest and dispose of several thousand pounds per acre of contaminated aboveground plant material, than to excavate and dispose of 1 to 5 million pounds of contaminated soil per acre (assumes contamination runs 3 ft deep). Our objective is to develop a genetics-based phytoremediation strategy for arsenic removal that can be used in any plant species. This strategy requires the enhanced expression of several transgenes from diverse sources. Our working hypothesis is that organ-specific expression of several genes controlling the transport, electrochemical state, and binding of arsenic will result in the efficient extraction and hyperaccumulation of arsenic into aboveground plant tissues. This hypothesis is supported by theoretical arguments and strong preliminary data. We proposed six Specific Aims focused on testing and developing this arsenic phytoremediation strategy. During the first 18 months of the grant we made significant progress on five Specific Aims and began work on the sixth as summarized below. Specific Aim 1: Enhance plant arsenic resistance and greatly expand sinks for arsenite by expressing elevated levels of thiol-rich, arsenic-binding peptides. Hyperaccumulation of arsenic depends upon making plants that are both highly tolerant to arsenic and that have the capacity to store large amounts of arsenic aboveground. Phytochelatins bind diverse thiol-reactive elements like As(III) and are synthesized from amino acids in a three-step enzymatic pathway utilizing three enzymes: ECS = gamma-glutamylcysteine synthetase; GS = GSH synthetase; and PS = phytochelatin synthase. We cloned each of the genes that encode these enzymes and used at least two different plant promoters to express them in transgenic Arabidopsis. We have shown that all three confer significant resistance to arsenic and allow rapid growth on a concentration of arsenic (300 micromolar) that kills wild-type seeds and plants.

  9. Lipid accumulation and biosynthesis genes response of the oleaginous Chlorella pyrenoidosa under three nutrition stressors

    PubMed Central

    2014-01-01

    Background Microalgae can accumulate considerable amounts of lipids under different nutrient-deficient conditions, making them as one of the most promising sustainable sources for biofuel production. These inducible processes provide a powerful experimental basis for fully understanding the mechanisms of physiological acclimation, lipid hyperaccumulation and gene expression in algae. In this study, three nutrient-deficiency strategies, viz nitrogen-, phosphorus- and iron-deficiency were applied to trigger the lipid hyperaccumulation in an oleaginous Chlorella pyrenoidosa. Regular patterns of growth characteristics, lipid accumulation, physiological parameters, as well as the expression patterns of lipid biosynthesis-related genes were fully analyzed and compared. Results Our results showed that all the nutrient stress conditions could enhance the lipid content considerably compared with the control. The total lipid and neutral lipid contents exhibit the most marked increment under nitrogen deficiency, achieving 50.32% and 34.29% of dry cell weight at the end of cultivation, respectively. Both photosynthesis indicators and reactive oxygen species parameters reveal that physiological stress turned up when exposed to nutrient depletions. Time-course transcript patterns of lipid biosynthesis-related genes showed that diverse expression dynamics probably contributes to the different lipidic phenotypes under stress conditions. By analyzing the correlation between lipid content and gene expression level, we pinpoint several genes viz. rbsL, me g6562, accA, accD, dgat g2354, dgat g3280 and dgat g7063, which encode corresponding enzymes or subunits of malic enzyme, ACCase and diacylglycerol acyltransferase in the de novo TAG biosynthesis pathway, are highly related to lipid accumulation and might be exploited as target genes for genetic modification. Conclusion This study provided us not only a comprehensive picture of adaptive mechanisms from physiological perspective, but also a number of targeted genes that can be used for a systematic metabolic engineering. Besides, our results also represented the feasibility of lipid production through trophic transition cultivation modes, throwing light on a two-stage microalgal lipid production strategy with which heterotrophy stage provides sufficient robust seed and nitrogen-starvation photoautotrophy stage enhances the overall lipid productivity. PMID:24479413

  10. Wild food plants used by the Tibetans of Gongba Valley (Zhouqu county, Gansu, China)

    PubMed Central

    2014-01-01

    Background The ethnobotany of Tibetans is a seriously under-studied topic. The aim of the study was to investigate knowledge and use of wild food plants in a valley inhabited by Tibetans in the Gannan Tibetan Autonomous Region. Methods The field research was carried out in a wooded mountain valley in 9 neighbouring villages the Zhouqu (Brugchu) county, and comprised 17 interviews with single informants and 14 group interviews, involving 122 people altogether. Results We recorded the use of 81 species of vascular plants from 41 families. Fruits formed the largest category, with 42 species, larger than the wild greens category, with 36 species. We also recorded the culinary use of 5 species of edible flowers, 7 species with underground edible organs and 5 taxa of fungi. On average, 16.2 edible taxa were listed per interview (median – 16). Green vegetables formed the largest category of wild foods (mean – 8.7 species, median – 9 species), but fruits were listed nearly as frequently (mean – 6.9, median – 6). Other categories were rarely mentioned: flowers (mean – 0.2, median – 0), underground edible parts (mean – 0.3, median – 0) and mushrooms (mean – 1.5, – median 1). Wild vegetables are usually boiled and/or fried and served as side-dishes (cai). They are often lacto-fermented. Wild fruits are mainly collected by children and eaten raw, they are not stored for further use. The most widely used wild vegetables are: Eleuterococcus spp., Pteridium aquilinum, Helwingia japonica, Aralia chinensis, Allium victorialis, Pteridium aquilinum, Ixeris chinensis, Thlaspi arvense and Chenopodium album. The culinary use of Caltha palustris as a green vegetable is very interesting. In its raw state, marsh marigold is a toxic plant, due to the presence of protoanemonin. In this area it is dried or lactofermented before use. The most commonly eaten fruits are: Pyrus xerophila, Prunus salicina, Berchemia sinica, Rubus spp. and Eleagnus umbellata. Conclusions The number of wild taxa eaten in the studied valley is relatively large compared to most studies from around the world. However, compared to the northern slope of the Qinling, in Shaanxi, the list is considerably shorter, in spite of the similar methodology applied and similar research effort involved. PMID:24502461

  11. Enhanced Heavy Metal Tolerance and Accumulation by Transgenic Sugar Beets Expressing Streptococcus thermophilus StGCS-GS in the Presence of Cd, Zn and Cu Alone or in Combination

    PubMed Central

    Liu, Dali; An, Zhigang; Mao, Zijun; Ma, Longbiao; Lu, Zhenqiang

    2015-01-01

    Phytoremediation is a promising means of ameliorating heavy metal pollution through the use of transgenic plants as artificial hyperaccumulators. A novel Streptococcus thermophilus ?-glutamylcysteine synthetase-glutathione synthetase (StGCS-GS) that synthesizes glutathione (GSH) with limited feedback inhibition was overexpressed in sugar beet (Beta vulgaris L.), yielding three transgenic lines (s2, s4 and s5) with enhanced tolerance to different concentrations of cadmium, zinc and copper, as indicated by their increased biomass, root length and relative growth compared with wild-type plants. Transgenic sugar beets accumulated more Cd, Zn and Cu ions in shoots than wild-type, as well as higher GSH and phytochelatin (PC) levels under different heavy metal stresses. This enhanced heavy metal tolerance and increased accumulation were likely due to the increased expression of StGCS-GS and consequent overproduction of both GSH and PC. Furthermore, when multiple heavy metal ions were present at the same time, transgenic sugar beets overexpressing StGCS-GS resisted two or three of the metal combinations (50 ?M Cd-Zn, Cd-Cu, Zn-Cu and Cd-Zn-Cu), with greater absorption in shoots. Additionally, there was no obvious competition between metals. Overall, the results demonstrate the explicit role of StGCS-GS in enhancing Cd, Zn and Cu tolerance and accumulation in transgenic sugar beet, which may represent a highly promising new tool for phytoremediation. PMID:26057126

  12. Role of transpiration and metabolism in translocation and accumulation of cadmium in tobacco plants (Nicotiana tabacum L.).

    PubMed

    Liu, Haiwei; Wang, Haiyun; Ma, Yibing; Wang, Haohao; Shi, Yi

    2016-02-01

    Tobacco plants grown in pots and in hydroponic culture accumulated cadmium (Cd) particularly: the Cd content of tobacco leaves exceeded 100 mg/kg and the enrichment factor (the ratio of Cd in leaves to that in soil) was more than 4. These high levels of accumulation identify tobacco as a hyperaccumulator of Cd. Two transpiration inhibitors (paraffin or CaCl2) and shade decreased the Cd content of tobacco leaves, and the decrease showed a linear relationship with the leaf transpiration rate. A metabolism inhibitor, namely 2,4-dinitrophenol (DNP), and low temperature (4 °C) also lowered the Cd content of tobacco leaves, but the inhibitory effect of low temperature was greater. In the half number of leaves that were shaded, the Cd content decreased to 26.5% of that in leaves that were not shaded in the same tobacco plants. These results suggests that translocation of Cd from the medium to the leaves is driven by the symplastic and the apoplastic pathways. Probably, of the two crucial steps in the translocation of Cd in tobacco plants, one, namely uptake from the medium to the xylem, is energy-dependent whereas the other, namely the transfer from the xylem to the leaves, is driven mainly by transpiration. PMID:26547876

  13. Progress toward clonable inorganic nanoparticles.

    PubMed

    Ni, Thomas W; Staicu, Lucian C; Nemeth, Richard S; Schwartz, Cindi L; Crawford, David; Seligman, Jeffrey D; Hunter, William J; Pilon-Smits, Elizabeth A H; Ackerson, Christopher J

    2015-10-15

    Pseudomonas moraviensis stanleyae was recently isolated from the roots of the selenium (Se) hyperaccumulator plant Stanleya pinnata. This bacterium tolerates normally lethal concentrations of SeO3(2-) in liquid culture, where it also produces Se nanoparticles. Structure and cellular ultrastructure of the Se nanoparticles as determined by cellular electron tomography shows the nanoparticles as intracellular, of narrow dispersity, symmetrically irregular and without any observable membrane or structured protein shell. Protein mass spectrometry of a fractionated soluble cytosolic material with selenite reducing capability identified nitrite reductase and glutathione reductase homologues as NADPH dependent candidate enzymes for the reduction of selenite to zerovalent Se nanoparticles. In vitro experiments with commercially sourced glutathione reductase revealed that the enzyme can reduce SeO3(2-) (selenite) to Se nanoparticles in an NADPH-dependent process. The disappearance of the enzyme as determined by protein assay during nanoparticle formation suggests that glutathione reductase is associated with or possibly entombed in the nanoparticles whose formation it catalyzes. Chemically dissolving the nanoparticles releases the enzyme. The size of the nanoparticles varies with SeO3(2-) concentration, varying in size form 5 nm diameter when formed at 1.0 ?M [SeO3(2-)] to 50 nm maximum diameter when formed at 100 ?M [SeO3(2-)]. In aggregate, we suggest that glutathione reductase possesses the key attributes of a clonable nanoparticle system: ion reduction, nanoparticle retention and size control of the nanoparticle at the enzyme site. PMID:26350616

  14. Assessment of bioaccumulation of heavy metals by different plant species grown on fly ash dump.

    PubMed

    Jambhulkar, Hemlata P; Juwarkar, Asha A

    2009-05-01

    A field experiment was conducted on a 10-hectare area on fly ash dump at Khaperkheda Thermal Power Plant, Nagpur, India, where different ecologically and economically important plant species were planted using bioremediation technology. The technology involves the use of organic amendment and selection of suitable plant species along with site-specific nitrogen-fixing strains of biofertilizers. The study was conducted to find out the metal accumulation potential of different plant species. The total heavy metal contents in fly ash were determined and their relative abundance was found in the order of Fe>Mn>Zn>Cu>Ni>Cr>Pb>Cd. Fly ash samples had acidic pH, low electrical conductivity, low level of organic carbon and trace amounts of N and P. Plantation of divergent species was done on fly ash dump using the bioremediation technique. After 3 years of plantation, luxuriant growth of these species was found covering almost the entire fly ash dump. The results of the metal analysis of these species indicated that iron accumulated to the greatest extent in vegetation followed by Mn, Ni, Zn, Cu, Cr and Pb. Cassia siamea was found to accumulate all metals at higher concentrations compared to other species. The experimental study revealed that C. siamea could be used as a hyper-accumulator plant for bioremediation of fly ash dump. PMID:19171381

  15. Organic acids, amino acids compositions in the root exudates and Cu-accumulation in castor (Ricinus communis L.) Under Cu stress.

    PubMed

    Huang, Guoyong; Guo, Guangguang; Yao, Shiyuan; Zhang, Na; Hu, Hongqing

    2016-01-01

    Ricinus communis L. is a hyperaccumulation plant newly discovered in an abandoned land of Cu mine in China. A hydroponic experiment was then carried out to determine the root exudates in the Cu-tolerant castor (Ricinus communis L.). Plants were grown in nutrient solution with increasing level of Cu doses (0, 100, 250, 500, and 750 ?mol/L Cu) in the form of CuSO4. Cu accumulation in the roots and shoots of castor, and root exudates collected from the castor were measured. The results indicated that the castor had a high Cu accumulation capacity and the Cu concentrations in the shoots and roots of the castor treated with 750 ?mol/L Cu were 177.1, 14586.7 mg/kg, respectively. Tartaric was the largest in the root exudates in terms of concentrations, which reached up to 329.13 ?mol/g (dry plant) in the level of 750 ?mol/L Cu. There was a significantly positive linear relationship between the Cu concentration in root and the concentration of succinic (R = 0.92, P < 0.05), tartaric (R = 0.96, P < 0.01), and citric (R = 0.89, P < 0.05). These results indicated that the difference in root exudation from castor could affect their Cu tolerance. What is more, significant is that the high tartaric and citric, the low oxalic and cysteine in the root exudation of castor contributed to toleration of high Cu concentrations. PMID:26220483

  16. Poplar maintains zinc homeostasis with heavy metal genes HMA4 and PCS1

    PubMed Central

    Adams, Joshua P.; Adeli, Ardeshir; Hsu, Chuan-Yu; Harkess, Richard L.; Page, Grier P.; dePamphilis, Claude W.; Schultz, Emily B.; Yuceer, Cetin

    2011-01-01

    Perennial woody species, such as poplar (Populus spp.) must acquire necessary heavy metals like zinc (Zn) while avoiding potential toxicity. Poplar contains genes with sequence homology to genes HMA4 and PCS1 from other species which are involved in heavy metal regulation. While basic genomic conservation exists, poplar does not have a hyperaccumulating phenotype. Poplar has a common indicator phenotype in which heavy metal accumulation is proportional to environmental concentrations but excesses are prevented. Phenotype is partly affected by regulation of HMA4 and PCS1 transcriptional abundance. Wild-type poplar down-regulates several transcripts in its Zn-interacting pathway at high Zn levels. Also, overexpressed PtHMA4 and PtPCS1 genes result in varying Zn phenotypes in poplar; specifically, there is a doubling of Zn accumulation in leaf tissues in an overexpressed PtPCS1 line. The genomic complement and regulation of poplar highlighted in this study supports a role of HMA4 and PCS1 in Zn regulation dictating its phenotype. These genes can be altered in poplar to change its interaction with Zn. However, other poplar genes in the surrounding pathway may maintain the phenotype by inhibiting drastic changes in heavy metal accumulation with a single gene transformation. PMID:21504875

  17. Betula pendula: A Promising Candidate for Phytoremediation of TCE in Northern Climates.

    PubMed

    Lewis, Jeffrey; Qvarfort, Ulf; Sjöström, Jan

    2015-01-01

    Betula pendula (Silver birch) trees growing on two contaminated sites were evaluated to assess their capacity to phytoscreen and phytoremediate chlorinated aliphatic compounds and heavy metals. Both locations are industrially-contaminated properties in central Sweden. The first was the site of a trichloroethylene (TCE) spill in the 1980s while the second was polluted with heavy metals by burning industrial wastes. In both cases, sap and sapwood from Silver birch trees were collected and analyzed for either chlorinated aliphatic compounds or heavy metals. These results were compared to analyses of the surface soil, vadose zone pore air and groundwater. Silver birch demonstrated the potential to phytoscreen and possibly phytoremediate TCE and related compounds, but it did not demonstrate the ability to effectively phytoextract heavy metals when compared with hyperaccumulator plants. The capacity of Silver birch to phytoremediate TCE appears comparable to tree species that have been employed in field-scale TCE phytoremediation efforts, such as Populus spp. and Eucalyptus sideroxylon rosea. PMID:25174420

  18. Potential of Mauritius Hemp (Furcraea gigantea Vent.) for the Remediation of Chromium Contaminated Soils.

    PubMed

    Ramana, Sivakoti; Biswas, Ashis K; Singh, Amar B; Ahirwar, Narendra K; Prasad, Ravulapalli D; Srivastava, Sanjay

    2015-01-01

    The present study was conducted to evaluate the ability of a high biomass producing, drought tolerant succulent plant Mauritius hemp (Furcraea gigantea Vent.) for its tolerance to different levels of Cr (0, 25, 50, 100 and 200 mg Cr kg soil(-1)) and its potential for phytoremediation purposes. Based on the data on inhibition of the growth of plants with Cr, tolerance index and grade of growth inhibition, it was observed that the plant could tolerate up to 50 mg Cr kg (-1) soil. Absorption of Cr from soil to plant and its translocation into plant tissues were discussed in terms of bio concentration factor (BCF), transfer factor (TF), and translocation efficiency (TE%). Cr was mainly accumulated in the roots and exclusion of Cr was found to be the principal physiological tolerance mechanism followed by a marked increase in proline, ascorbic acid, total free amino acids in the leaf tissue and malic acid in the rhizosphere samples to counter Cr stress. Based on the tissue concentration of Cr (< 300 ?g g(-1) in the leaves and TF<1), it was concluded that, Furcraea gigantea could not be considered a hyperaccumulator and therefore unsuitable for phytoextraction of Cr. Nevertheless, Furcraea gigantea could be a suitable candidate for phytostablization of Cr contaminated soils. PMID:25976885

  19. The Growth Reduction Associated with Repressed Lignin Biosynthesis in Arabidopsis thaliana Is Independent of Flavonoids[C

    PubMed Central

    Li, Xu; Bonawitz, Nicholas D.; Weng, Jing-Ke; Chapple, Clint

    2010-01-01

    Defects in phenylpropanoid biosynthesis arising from deficiency in hydroxycinnamoyl CoA:shikimate hydroxycinnamoyl transferase (HCT) or p-coumaroyl shikimate 3?-hydroxylase (C3?H) lead to reduced lignin, hyperaccumulation of flavonoids, and growth inhibition in Arabidopsis thaliana. It was previously reported that flavonoid-mediated inhibition of auxin transport is responsible for growth reduction in HCT-RNA interference (RNAi) plants. This conclusion was based on the observation that simultaneous RNAi silencing of HCT and chalcone synthase (CHS), an enzyme essential for flavonoid biosynthesis, resulted in less severe dwarfing than silencing of HCT alone. In an attempt to extend these results using a C3?H mutant (ref8) and a CHS null mutant (tt4-2), we found that the growth phenotype of the ref8 tt4-2 double mutant, which lacks flavonoids, is indistinguishable from that of ref8. Moreover, using RNAi, we found that the relationship between HCT silencing and growth inhibition is identical in both the wild type and tt4-2. We conclude from these results that the growth inhibition observed in HCT-RNAi plants and the ref8 mutant is independent of flavonoids. Finally, we show that expression of a newly characterized gene bypassing HCT and C3?H partially restores both lignin biosynthesis and growth in HCT-RNAi plants, demonstrating that a biochemical pathway downstream of coniferaldehyde, probably lignification, is essential for normal plant growth. PMID:20511296

  20. Emission and control characteristics for incineration of Sedum plumbizincicola biomass in a laboratory-scale entrained flow tube furnace.

    PubMed

    Wu, Longhua; Zhong, Daoxu; Du, Yingzhe; Lu, Shengyong; Fu, Dengqiang; Li, Zhu; Li, Xiaodong; Chi, Yong; Luo, Yongming; Yan, Jianhua

    2013-01-01

    Experiments were conducted to investigate and control pollutant emission from incineration of Sedum plumbizincicola plants on a laboratory scale using an entrained flow tube furnace. Without control technologies, the flue gas contained 0.101 mg Nm(-3) of Cd, 46.4 mg Nm(-3) of Zn, 553 mg Nm(-3) of NOx, 131 pg Nm(-3) of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/Fs) and 35.4 mg Nm(-3) of polycyclic aromatic hydrocarbons (PAHs). In pollutants control experiments. Al2O3, CaO, and kaolin were compared as adsorbents and activated carbon was used as an end-of-pipe method for the capture of pollutants. Kaolin, the most effective of the three adsorbents, removed 91.2% of the Cd in flue gas. While 97.6% of the Cd and 99.6% of the PAHs were removed by activated carbon. Incineration may therefore be regarded as a viable option for the safe disposal of the biomass of the zinc and cadmium hyperaccumulator species S. plumbizincicola. PMID:23488008

  1. Selenium Cycling Across Soil-Plant-Atmosphere Interfaces: A Critical Review

    PubMed Central

    Winkel, Lenny H.E.; Vriens, Bas; Jones, Gerrad D.; Schneider, Leila S.; Pilon-Smits, Elizabeth; Bañuelos, Gary S.

    2015-01-01

    Selenium (Se) is an essential element for humans and animals, which occurs ubiquitously in the environment. It is present in trace amounts in both organic and inorganic forms in marine and freshwater systems, soils, biomass and in the atmosphere. Low Se levels in certain terrestrial environments have resulted in Se deficiency in humans, while elevated Se levels in waters and soils can be toxic and result in the death of aquatic wildlife and other animals. Human dietary Se intake is largely governed by Se concentrations in plants, which are controlled by root uptake of Se as a function of soil Se concentrations, speciation and bioavailability. In addition, plants and microorganisms can biomethylate Se, which can result in a loss of Se to the atmosphere. The mobilization of Se across soil-plant-atmosphere interfaces is thus of crucial importance for human Se status. This review gives an overview of current knowledge on Se cycling with a specific focus on soil-plant-atmosphere interfaces. Sources, speciation and mobility of Se in soils and plants will be discussed as well as Se hyperaccumulation by plants, biofortification and biomethylation. Future research on Se cycling in the environment is essential to minimize the adverse health effects associated with unsafe environmental Se levels. PMID:26035246

  2. Stability of Tl(III) in the context of speciation analysis of thallium in plants.

    PubMed

    Sadowska, Monika; Biadu?, Ewa; Krasnod?bska-Ostr?ga, Beata

    2016-02-01

    The paper presents both "good" and "bad" results obtained during speciation analysis of thallium in plant tissues of a hyperaccumulator of this metal. The object was white mustard - Sinapis alba L. In this plant there were found traces of trivalent thallium. The crucial point of this study (especially in the case of so unstable thallium form as Tl(III)) was to prove that the presence of Tl(III) was not caused by the procedure of sample preparation itself, and that the whole analytical method provides reliable results. Choice of the method for conservation of the initial speciation, extraction with the highest efficiency and proving the correctness of the obtained data were the most difficult parts of the presented study. It was found that: both freezing and drying cause significant changes in the speciation of thallium; quantitative analysis could be performed only with fresh tissues of mustard plants; only short-term storage of an extract from fresh plant tissues is possible; the methodology is not the source of thallium (III); only the presence of DTPA can greatly limit the reduction of TI(III) to TI(I) (up to 1-3%); the UV irradiation results in disintegration of TI(III)DTPA in the presence of plant matrix (reduction up to 90%). PMID:26465967

  3. BjDHNs confer heavy-metal tolerance in plants.

    PubMed

    Xu, Jin; Zhang, Yu Xiu; Wei, Wei; Han, Lu; Guan, Zi Qiu; Wang, Zi; Chai, Tuan Yao

    2008-02-01

    Dehydrin gene transcript could be induced by heavy metals, and some dehydrins possess the ability to bind metals. However, the correlation between dehydrins and heavy-metal stress is unknown. In order to elucidate the contribution of dehydrins to heavy-metal stress tolerance in plants, we cloned two SK(2)-type dehydrin genes from heavy-metal hyperaccumulator Brassica juncea, and investigated their Cd/Zn tolerance in transgenic plants. Semi-quantitative RT-PCR analysis revealed that BjDHN2/BjDHN3 expressed in the leaves, stems and roots at a low level and were up-regulated by heavy metals. Antisense BjDHN3 Brassica juncea plants showed more electrolyte leakage and higher malondialdehyde production than the control plants when exposed to heavy metals, and the total amount of metals accumulated in the whole plant was reduced. Transgenic tobacco plants overexpressing BjDHN2/BjDHN3 showed lower electrolyte leakage and malondialdehyde production than the control plants when exposed to Cd/Zn. These results indicated that BjDHN2/BjDHN3 enhanced the tolerance for heavy metals by reducing lipid peroxidation and maintaining membrane stability in the plants. PMID:18219589

  4. Determining soil enzyme activities for the assessment of fungi and citric acid-assisted phytoextraction under cadmium and lead contamination.

    PubMed

    Mao, Liang; Tang, Dong; Feng, Haiwei; Gao, Yang; Zhou, Pei; Xu, Lurong; Wang, Lumei

    2015-12-01

    Microorganism or chelate-assisted phytoextraction is an effective remediation tool for heavy metal polluted soil, but investigations into its impact on soil microbial activity are rarely reported. Consequently, cadmium (Cd)- and lead (Pb)-resistant fungi and citric acid (CA) were introduced to enhance phytoextraction by Solanum nigrum L. under varied Cd and Pb pollution levels in a greenhouse pot experiment. We then determined accumulation of Cd and Pb in S. nigrum and the soil enzyme activities of dehydrogenase, phosphatase, urease, catalase, sucrase, and amylase. Detrended canonical correspondence analysis (DCCA) was applied to assess the interactions between remediation strategies and soil enzyme activities. Results indicated that the addition of fungi, CA, or their combination enhanced the root biomass of S. nigrum, especially at the high-pollution level. The combined treatment of CA and fungi enhanced accumulation of Cd about 22-47 % and of Pb about 13-105 % in S. nigrum compared with the phytoextraction alone. However, S. nigrum was not shown to be a hyperaccumulator for Pb. Most enzyme activities were enhanced after remediation. The DCCA ordination graph showed increasing enzyme activity improvement by remediation in the order of phosphatase, amylase, catalase, dehydrogenase, and urease. Responses of soil enzyme activities were similar for both the addition of fungi and that of CA. In summary, results suggest that fungi and CA-assisted phytoextraction is a promising approach to restoring heavy metal polluted soil. PMID:26286803

  5. Phytoremediation potential of indigenous plants from Thai Nguyen province, Vietnam.

    PubMed

    Anh, Bui Thi Kim; Kim, Dang Dinh; Tua, Tran Van; Kien, Nguyen Trung; Anh, Do Tuan

    2011-03-01

    This study was focused on determining Arsenic (As), Lead (Pb), Cadmium (Cd) and Zinc (Zn) in 33 indigenous plants and 12 soil in-situ plant samples in Thai Nguyen Province, Vietnam. The results showed that the soils of surveyed mining areas contained 181.2- 6754.3 mg kg(-1) As, 235.5-4337.2 mg kg(-1) Pb, 0.8- 419 mg kg(-1) Cd and 361.8-17565.1 mg kg(-1) Zn depending on the characteristics of each mining site. These values are much higher than those typical for normal soil. The heavy metal uptake into shoots and roots of 33 indigenous plant species was also determined. Two species of the plants investigated, Pteris vittata L. and Pityrogramma calomelanos L. were As hyperaccumulators, containing more than 0.1% heavy metals in their shoots. Eleusine indica L., Cynodon dactylon L., Cyperus rotundus L. and Equisetum ramosissimum (Vauch) accumulate very high Pb (0.15-0.65%) and Zn (0.22-1.56%) concentration in their roots. Additional experiments to clarify the potential of six these plants as good candidates for phytoremediation of heavy metal pollution soil are being carried out in our laboratory. PMID:21882664

  6. Targeted Disruption of Drosophila Roc1b Reveals Functional Differences in the Roc Subunit of Cullin-dependent E3 Ubiquitin Ligases

    PubMed Central

    Donaldson, Timothy D.; Noureddine, Maher A.; Reynolds, Patrick J.; Bradford, William; Duronio, Robert J.

    2004-01-01

    Cullin-dependent ubiquitin ligases regulate a variety of cellular and developmental processes by recruiting specific proteins for ubiquitin-mediated degradation. Cullin proteins form a scaffold for two functional modules: a catalytic module comprised of a small RING domain protein Roc1/Rbx1 and a ubiquitin-conjugating enzyme (E2), and a substrate recruitment module containing one or more proteins that bind to and bring the substrate in proximity to the catalytic module. Here, we present evidence that the three Drosophila Roc proteins are not functionally equivalent. Mutation of Roc1a causes lethality that cannot be rescued by expression of Roc1b or Roc2 by using the Roc1a promoter. Roc1a mutant cells hyperaccumulate Cubitus interruptus, a transcription factor that mediates Hedgehog signaling. This phenotype is not rescued by expression of Roc2 and only partially by expression of Roc1b. Targeted disruption of Roc1b causes male sterility that is partially rescued by expression of Roc1a by using the Roc1b promoter, but not by similar expression of Roc2. These data indicate that Roc proteins play nonredundant roles during development. Coimmunoprecipitation followed by Western or mass spectrometric analysis indicate that the three Roc proteins preferentially bind certain Cullins, providing a possible explanation for the distinct biological activities of each Drosophila Roc/Rbx. PMID:15331761

  7. Extensive Variation in Cadmium Tolerance and Accumulation among Populations of Chamaecrista fasciculata

    PubMed Central

    Henson, Tessa M.; Cory, Wendy; Rutter, Matthew T.

    2013-01-01

    Plant populations may vary substantially in their tolerance for and accumulation of heavy metals, and assessment of this variability is important when selecting species to use in restoration or phytoremediation projects. We examined the population variation in cadmium tolerance and accumulation in a leguminous pioneer species native to the eastern United States, the partridge pea (Chamaecrista fasciculata). We assayed growth, reproduction and patterns of cadmium accumulation in six populations of C. fasciculata grown on a range of cadmium-contaminated soils. In general, C. fasciculata exhibited tolerance in low to moderate soil cadmium concentrations. Both tolerance and accumulation patterns varied across populations. C. fasciculata exhibited many characteristics of a hyperaccumulator species, with high cadmium uptake in shoots and roots. However, cadmium was excluded from extrafloral nectar. As a legume with tolerance for moderate cadmium contamination, C. fasciculata has potential for phytoremediation. However, our findings also indicate the importance of considering the effects of genetic variation on plant performance when screening plant populations for utilization in remediation and restoration activities. Also, there is potential for cadmium contamination to affect other species through contamination of leaves, fruits, flowers, pollen and root nodules. PMID:23667586

  8. Studying the enhanced phytoremediation of lead contaminated soils via laser induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Hassan, M.; Sighicelli, M.; Lai, A.; Colao, F.; Ahmed, A. H. Hanafy; Fantoni, R.; Harith, M. A.

    2008-10-01

    Phytoremediation popularly known as 'green clean technology' is a new promising technology used for toxic contaminants removal from the environment such as heavy metals (HMs), adopting suitable plants. This concept is increasingly being adopted as it is a cost effective and environmentally friendly alternative to traditional methods of treatment. This study was focused on using scented geranium, Pelargonium zonale, as accumulator or hyperaccumulator plant for natural lead extraction from artificially contaminated soil with different Pb concentrations (0, 2000, 5000, 7000 ppm). Utilization of EDTA as a chelator, that would permit higher metal availability and uptake by the tested plants roots, was also tested. Laser Induced Breakdown Spectroscopy (LIBS) was used to follow up Pb concentrations in both soil and plant green harvestable parts known as shoots, before, during and after lead addition in soil. LIBS measurements were conducted in a microdestructive way by focusing a high energy Nd:YAG laser, emitting at 1064 nm, on plant and soil samples previously dried, homogenized and pressed in pellets. The emitted LIBS spectra were acquired by a gated CCD after dispersion on a monochromator and analyzed to retrieve relative concentrations of the selected HM both in the soil and on plants as a function of the time after doping and eventual chelator addition. EDTA was found to enhance Pb uptake from the soil which increased with time, good correlation was found between LIBS and ICP-OES results of plant tissues spectrochemical analysis.

  9. Arsenic tolerance, uptake, and accumulation by nonmetallicolous and metallicolous populations of Pteris vittata L.

    PubMed

    Wu, Fuyong; Deng, Dan; Wu, Shengchun; Lin, Xiangui; Wong, Ming Hung

    2015-06-01

    Although it is known that the first As hyperaccumulator identified, Pteris vittata L., could exist in As-contaminated as well as uncontaminated soils, intra-specific variation in As accumulation among metallicolous (from As-contaminated soils) and nonmetallicolous populations (from uncontaminated soils) of P. vittata has not been fully explored. Variations in As concentrations of fronds were observed in three nonmetallicolous populations and four metallicolous populations of P. vittata collected from southeast China. The kinetics study showed that the concentration-dependent influx of arsenate and arsenite observed followed Michaelis-Menten kinetics, and that the average V max for arsenate and arsenite was apparently larger in the three nonmetallicolous populations than that in the three metallicolous populations. The pot trials indicated that the nonmetallicolous populations had significantly (p?

  10. Ectopic expression of RNF168 and 53BP1 increases mutagenic but not physiological non-homologous end joining

    PubMed Central

    Zong, Dali; Callén, Elsa; Pegoraro, Gianluca; Lukas, Claudia; Lukas, Jiri; Nussenzweig, André

    2015-01-01

    DNA double strand breaks (DSBs) formed during S phase are preferentially repaired by homologous recombination (HR), whereas G1 DSBs, such as those occurring during immunoglobulin class switch recombination (CSR), are repaired by non-homologous end joining (NHEJ). The DNA damage response proteins 53BP1 and BRCA1 regulate the balance between NHEJ and HR. 53BP1 promotes CSR in part by mediating synapsis of distal DNA ends, and in addition, inhibits 5’ end resection. BRCA1 antagonizes 53BP1 dependent DNA end-blocking activity during S phase, which would otherwise promote mutagenic NHEJ and genome instability. Recently, it was shown that supra-physiological levels of the E3 ubiquitin ligase RNF168 results in the hyper-accumulation of 53BP1/BRCA1 which accelerates DSB repair. Here, we ask whether increased expression of RNF168 or 53BP1 impacts physiological versus mutagenic NHEJ. We find that the anti-resection activities of 53BP1 are rate-limiting for mutagenic NHEJ but not for physiological CSR. As heterogeneity in the expression of RNF168 and 53BP1 is found in human tumors, our results suggest that deregulation of the RNF168/53BP1 pathway could alter the chemosensitivity of BRCA1 deficient tumors. PMID:25916843

  11. Assessment of the root system of Brassica juncea (L.) czern. and Bidens pilosa L. exposed to lead polluted soils using rhizobox systems.

    PubMed

    Soledad Graziani, Natalia; Salazar, María Julieta; Pignata, María Luisa; Rodriguez, Judith Hebelen

    2016-03-01

    The purpose of this study was to compare the behavior of the root system of one of the most frequently cited species in phytoremediation Indian mustard [Brassica juncea (L.) Czern.] and a representative perennial herb (Bidens pilosa L.) native of Argentina, for different concentrations of lead in soils through chemical and visualization techniques of the rhizosphere. Lead polluted soils from the vicinity of a lead recycling plant in the locality of Bouwer, were used in juxtaposed rhizobox systems planted with seedlings of B. juncea and B. pilosa with homogeneous and heterogeneous soil treatments. Root development, pH changes in the rhizosphere, dry weight biomass, lead content of root and aerial parts and potential extraction of lead by rhizosphere exudates were determined. In both species lead was mainly accumulated in roots. However, although B. juncea accumulated more lead than B. pilosa at elevated concentrations in soils, the latter achieved greater root and aerial development. No changes in the pH of the rhizosphere associated to lead were observed, despite different extractive potentials of lead in the exudates of the species analyzed. Our results indicated that Indian mustard did not behave as a hyperaccumulator in the conditions of the present study. PMID:26292209

  12. Combined effects of cadmium and zinc on growth, tolerance, and metal accumulation in Chara australis and enhanced phytoextraction using EDTA.

    PubMed

    Clabeaux, Bernadette L; Navarro, Divina A; Aga, Diana S; Bisson, Mary A

    2013-12-01

    Chara australis (R. Br.) is a macrophytic alga that can grow in and accumulate Cd from artificially contaminated sediments. We investigated the effects of Zn independently and in combination with Cd on C. australis growth, metal tolerance, and uptake. Plant growth was reduced at concentrations ? 75 mg Zn (kg soil)?¹. Zn also increased the concentration of glutathione in the plant, suggesting alleviation of stress. Phytotoxic effects were observed at ? 250 mg added Zn (kg soil)?¹. At 1.5mg Zn (kg soil)?¹, the rhizoid bioconcentration factor (BCF) was >1.0 for both Cd and Zn. This is a criterion for hyperaccumulator status, a commonly used benchmark for utility in remediation of contaminated soils by phytoextraction. There was no significant interaction between Cd and Zn on accumulation, indicating that Chara should be effective at phytoextraction of mixed heavy metal contamination in sediments. The effects of the chelator, ethylenediaminetetraacetic acid (EDTA), were also tested. Moderate levels of EDTA increased Cd and Zn accumulation in rhizoids and Cd BCF of shoots, enhancing Chara's potential in phytoremediation. This study demonstrates for the first time the potential of macroalgae to remove metals from sediments in aquatic systems that are contaminated with a mixture of metals. PMID:24035462

  13. Phytotoxicity of cobalt ions on the duckweed Lemna minor - Morphology, ion uptake, and starch accumulation.

    PubMed

    Sree, K Sowjanya; Keresztes, Áron; Mueller-Roeber, Bernd; Brandt, Ronny; Eberius, Matthias; Fischer, Wolfgang; Appenroth, Klaus-J

    2015-07-01

    Cobalt (Co2+) inhibits vegetative growth of Lemna minor gradually from 1 ?M to 100 ?M. Fronds accumulated up to 21 mg Co2+ g(-1) dry weight at 10 ?M external Co2+ indicating hyperaccumulation. Interestingly, accumulation of Co2+ did not decrease the iron (Fe) content in fronds, highlighting L. minor as a suitable system for studying effects of Co2+ undisturbed by Fe deficiency symptoms unlike most other plants. Digital image analysis revealed the size distribution of fronds after Co2+ treatment and also a reduction in pigmentation of newly formed daughter fronds unlike the mother fronds during the 7-day treatment. Neither chlorophyll nor photosystem II fluorescence changed significantly during the initial 4d, indicating effective photosynthesis. During the later phase of the 7-day treatment, however, chlorophyll content and photosynthetic efficiency decreased in the Co2+-treated daughter fronds, indicating that Co2+ inhibits the biosynthesis of chlorophyll rather than leading to the destruction of pre-existing pigment molecules. In addition, during the first 4d of Co2+ treatment starch accumulated in the fronds and led to the transition of chloroplasts to chloro-amyloplasts and amylo-chloroplasts, while starch levels strongly decreased thereafter. PMID:25840119

  14. Aquatic arsenic: phytoremediation using floating macrophytes.

    PubMed

    Rahman, M Azizur; Hasegawa, H

    2011-04-01

    Phytoremediation, a plant based green technology, has received increasing attention after the discovery of hyperaccumulating plants which are able to accumulate, translocate, and concentrate high amount of certain toxic elements in their above-ground/harvestable parts. Phytoremediation includes several processes namely, phytoextraction, phytodegradation, rhizofiltration, phytostabilization and phytovolatilization. Both terrestrial and aquatic plants have been tested to remediate contaminated soils and waters, respectively. A number of aquatic plant species have been investigated for the remediation of toxic contaminants such as As, Zn, Cd, Cu, Pb, Cr, Hg, etc. Arsenic, one of the deadly toxic elements, is widely distributed in the aquatic systems as a result of mineral dissolution from volcanic or sedimentary rocks as well as from the dilution of geothermal waters. In addition, the agricultural and industrial effluent discharges are also considered for arsenic contamination in natural waters. Some aquatic plants have been reported to accumulate high level of arsenic from contaminated water. Water hyacinth (Eichhornia crassipes), duckweeds (Lemna gibba, Lemna minor, Spirodela polyrhiza), water spinach (Ipomoea aquatica), water ferns (Azolla caroliniana, Azolla filiculoides, and Azolla pinnata), water cabbage (Pistia stratiotes), hydrilla (Hydrilla verticillata) and watercress (Lepidium sativum) have been studied to investigate their arsenic uptake ability and mechanisms, and to evaluate their potential in phytoremediation technology. It has been suggested that the aquatic macrophytes would be potential for arsenic phytoremediation, and this paper reviews up to date knowledge on arsenic phytoremediation by common aquatic macrophytes. PMID:21435676

  15. Phytoaccumulation of Heavy Metals in Natural Vegetation at the Municipal Wastewater Site in Abbottabad, Pakistan.

    PubMed

    Irshad, Muhammad; Ruqia, Bibi; Hussain, Zahid

    2015-01-01

    Heavy metal accumulation in crops and soils from wastewater irrigation poses a significant threat to the human health. A study was carried out to investigate the removal potential of heavy metals (HM) by native plant species, namely Cannabis sativa L., Chenopodium album L., Datura stramonium L., Sonchus asper L., Amaranthus viridus L., Oenothera rosea (LHer), Xanthium stramonium L., Polygonum macalosa L., Nasturtium officinale L. and Conyza canadensis L. growing at the municipal wastewater site in Abbottabad city, Pakistan. The HM concentrations varied among plants depending on the species. Metal concentrations across species varied in the order iron (Fe) > zinc (Zn) > chromium (Cr) > nickel (Ni) > cadmium (Cd). Majority of the species accumulated more HM in roots than shoots. Among species, the concentrations (both in roots and shoots) were in the order C. sativa > C. album > X. stramonium > C. canadensis > A. viridus > N. officinale > P. macalosa > D. stramonium > S. asper > O. rosea. No species was identified as a hyperaccumulator. All species exhibited a translocation factor (TF) less than 1. Species like C. sativa, C. album and X. stramonium gave higher (> 1) biological concentration factor (BCF) and biological accumulation coefficient (BAC) especially for Fe, Cr and Cd than other species. Higher accumulation of heavy metals in these plant species signifies the general application of these species for phytostabilization and phytoextraction of HM from polluted soils. PMID:26366840

  16. Impacts of silver nanoparticles on bacterial species B. subtilis and E. coli and the major crop plant Z. mays

    NASA Astrophysics Data System (ADS)

    Doody, Michael A.

    This thesis examines the impacts of citrate-coated silver nanoparticles (c-AgNPs) on two species of bacteria (Bacillus subtilis and Escherichia coli), the major crop plant Zea mays, and the beneficial plant-microbe relationship between Z. mays and B. subtilis. AgNPs are an increasing component of antimicrobial consumer, industrial, and military products. This has led to widespread scientific concern for the ecological safety outside their intended use. An overview of their history, use, and toxicity was used to inform the design of experiments and resulting data. Growth inhibition and sub-lethal toxic effects were used to assess the effects of c-AgNP exposure to bacteria. Similar analytical methods were used to quantify the response of Z. mays to c-AgNP exposure. Results showed that exposure to c-AgNP significantly reduced the growth of bacterial populations and alters their growth kinetics. Z. mays experienced significant sub-lethal effects due to exposure, including reduced root length and biomass, and hyper-accumulated Ag in root tissues. Beneficial interactions between B. subtilis and Z. mays were reduced as both species suffered sub-lethal effects of exposure to c-AgNPs.

  17. Antimony in the Soil-Plant System in an Sb Mining/Smelting Area of Southwest China.

    PubMed

    Ning, Zengping; Xiao, Tangfu; Xiao, Enzong

    2015-01-01

    The distribution, bioavailability, and accumulation of antimony (Sb) at the interface of rhizospheric soils and indigenous plants from a large Sb mining/smelting area in Southwest China were explored. Results showed that the local soil was severely polluted by Sb, and the aluminum magnesium silicate minerals and the carbonate fraction may mainly contribute to bound Sb. The sequential extraction results of soil samples revealed that the portion of bioavailable Sb was low, but the bioavailable Sb concentration was up to 67.2 mg/kg, due to high total Sb concentrations in the soil. The Sb content in local plants showed a wide range, from 21 to 21148 mg/kg. The species of Chenopodium album Linn., Sedum emarginatum Migo, and Sedum lineare Thunb showed high accumulation of Sb at levels of above 1000 mg/kg. The Sb contents in the tissues for most plants decreased with the order of root > leaf > stem. The bioaccumulation coefficients and/or the biological transfer factors for most plants were less than 1. All of the studied plant species were not identified as Sb-hyperaccumulators, but the species of Chenopodium album Linn., Sedum emarginatum Migo, and Sedum lineare Thunb could be applied as alternative plants for phytoremediating Sb-polluted soils. PMID:26067424

  18. An abandoned copper mining site in cyprus and assessment of metal concentrations in plants and soil.

    PubMed

    Baycu, G; Tolunay, D; Ozden, H; Csatari, I; Karadag, S; Agba, T; Rognes, S E

    2015-01-01

    Mining is an important source of metal pollution in the environment and abandoned mines are extremely restricted habitats for plants. Some plant species growing on metalliferous soils around mine tailings and spoil-heaps are metal-tolerant and accumulate high concentrations of metals. In this investigation, we aimed to perform a research in the CMC-abandoned copper mining area in Lefke-North Cyprus to assess the recent metal pollution in soil and plant systems. We collected 16 soil samples and 25 plant species from 8 localities around the vicinity of tailing ponds. Some concentrations of metals in soil samples varied from 185 to 1023 mg kg(-1) Cu, 15.2 to 59.2 mg kg(-1) Ni, 2.3 to 73.6 mg kg(-1) Cd and metals for plants ranged from 0.135 to 283 mg kg(-1) Cu, 0.26 to 31.2 mg kg(-1) Ni, 0.143 to 277 mg kg(-1) Cd. Atriplex semibaccata, Acacia cyanophylla, Erodium spp., Inula viscosa, Juncus sp., Oxalis pes-caprea, Pistacia lentiscus, Senecio vulgaris and Tragopogon sinuatus accumulated higher concentrations. BCF for Atriplex semibaccata was found very high, for this reason this plant can tentatively be considered as a hyperaccumulator of Cu and Cd, but it needs further investigation for its potential in phytoremediation. PMID:25976876

  19. Novel Nickel Resistance Genes from the Rhizosphere Metagenome of Plants Adapted to Acid Mine Drainage? †

    PubMed Central

    Mirete, Salvador; de Figueras, Carolina G.; González-Pastor, Jose E.

    2007-01-01

    Metal resistance determinants have traditionally been found in cultivated bacteria. To search for genes involved in nickel resistance, we analyzed the bacterial community of the rhizosphere of Erica andevalensis, an endemic heather which grows at the banks of the Tinto River, a naturally metal-enriched and extremely acidic environment in southwestern Spain. 16S rRNA gene sequence analysis of rhizosphere DNA revealed the presence of members of five phylogenetic groups of Bacteria and the two main groups of Archaea mostly associated with sites impacted by acid mine drainage (AMD). The diversity observed and the presence of heavy metals in the rhizosphere led us to construct and screen five different metagenomic libraries hosted in Escherichia coli for searching novel nickel resistance determinants. A total of 13 positive clones were detected and analyzed. Insights about their possible mechanisms of resistance were obtained from cellular nickel content and sequence similarities. Two clones encoded putative ABC transporter components, and a novel mechanism of metal efflux is suggested. In addition, a nickel hyperaccumulation mechanism is proposed for a clone encoding a serine O-acetyltransferase. Five clones encoded proteins similar to well-characterized proteins but not previously reported to be related to nickel resistance, and the remaining six clones encoded hypothetical or conserved hypothetical proteins of uncertain functions. This is the first report documenting nickel resistance genes recovered from the metagenome of an AMD environment. PMID:17675438

  20. Molecular binding mechanisms of manganese to the root cell wall of Phytolacca americana L. using multiple spectroscopic techniques.

    PubMed

    Xu, Xianghua; Yang, Jianjun; Zhao, Xiaoyan; Zhang, Xuesong; Li, Renying

    2015-10-15

    The root cell wall (RCW) of Mn hyperaccumulator Phytolacca americana L. (P. americana) plays an important role in immobilizing and detoxifying excessive Mn, but the molecular binding mechanism of Mn to RCW has been little studied. This study investigated the effect of varied pH on Mn adsorption by the isolated RCW from P. americana in batch experiments, and explored the binding mechanisms of Mn to RCW using Fourier transform infrared spectroscopy (FTIR), synchrotron-based X-ray absorption near-edge structure (XANES), and extended X-ray fine structure spectroscopy (EXAFS). Results showed that Mn binding capacity depends on solution pH, with an optimal pH of 5.0-6.0. Experimental isotherm data could be successfully modeled by the Langmuir and Freundlich equations; the estimated maximum Mn adsorption capacity was 5.446 mg g(-1) according to the established Langmuir isotherm. FTIR spectroscopy demonstrated hydroxyl and carboxyl groups were probably involved in the Mn binding process. XANES results showed that Mn remained as Mn(II) after adsorption on RCW, without any change of oxidation state; EXAFS analysis further revealed that Mn was complexed to RCW via bidentate inner-sphere coordination with carboxyl, which provides new structure information of Mn adsorbed on biomaterials and accounted for high Mn accumulation on RCW of P. americana. PMID:25917696

  1. Removing heavy metals from synthetic effluents using "kamikaze" Saccharomyces cerevisiae cells.

    PubMed

    Ruta, Lavinia; Paraschivescu, Codruta; Matache, Mihaela; Avramescu, Sorin; Farcasanu, Ileana Cornelia

    2010-01-01

    One key step of the bioremediation processes designed to clean up heavy metal contaminated environments is growing resistant cells that accumulate the heavy metals to ensure better removal through a combination of biosorption and continuous metabolic uptake after physical adsorption. Saccharomyces cerevisiae cells can easily act as cation biosorbents, but isolation of mutants that are both hyperaccumulating and tolerant to heavy metals proved extremely difficult. Instead, mutants that are hypersensitive to heavy metals due to increased and continuous uptake from the environment were considered, aiming to use such mutants to reduce the heavy metal content of contaminated waters. In this study, the heavy metal hypersensitive yeast strain pmr1Delta was investigated for the ability to remove Mn2+, Cu2+, Co2+, or Cd2+ from synthetic effluents. Due to increased metal accumulation, the mutant strain was more efficient than the wild-type in removing Mn2+, Cu2+, or Co2+ from synthetic effluents containing 1-2 mM cations, with a selectivity and also in removing Mn2+ and Cd2+ from synthetic effluents containing 20-50 microM cations, with a selectivity Mn2+ > Cd2+. PMID:19795117

  2. Aluminium stress disrupts metabolic performance of Plantago almogravensis plantlets transiently.

    PubMed

    Grevenstuk, Tomás; Moing, Annick; Maucourt, Mickaël; Deborde, Catherine; Romano, Anabela

    2015-12-01

    Little is known about how tolerant plants cope with internalized aluminium (Al). Tolerant plants are known to deploy efficient detoxification mechanisms, however it is not known to what extent the primary and secondary metabolism is affected by Al. The aim of this work was to study the metabolic repercussions of Al stress in the tolerant plant Plantago almogravensis. P. almogravensis is well adapted to acid soils where high concentrations of free Al are found and has been classified as a hyperaccumulator. In vitro reared plantlets were used for this purpose in order to control Al exposure rigorously. The metabolome of P. almogravensis plantlets as well as its metabolic response to the supply of sucrose was characterized. The supply of sucrose leads to an accumulation of amino acids and secondary metabolites and consumption of carbohydrates that result from increased metabolic activity. In Al-treated plantlets the synthesis of amino acids and secondary metabolites is transiently impaired, suggesting that P. almogravensis is able to recover from the Al treatment within the duration of the trials. In the presence of Al the consumption of carbohydrate resources is accelerated. The content of some metabolic stress markers also demonstrates that P. almogravensis is highly adapted to Al stress. PMID:26433896

  3. The contribution of endophytic bacteria to Albizia lebbeck-mediated phytoremediation of tannery effluent contaminated soil.

    PubMed

    Manikandan, Muthu; Kannan, Vijayaraghavan; Mendoza, Ordetta Hannah; Kanimozhi, Mahalingam; Chun, Sechul; Paši?, Lejla

    2016-01-01

    Toxicity of chromium often impairs the remediation capacity of plants used in phytoremediation of polluted soils. In this study, we have identified Albizia lebbeck as a prospective chromium hyperaccumulator and examined cultivable diversity of endophytes present in chromium-treated and control saplings. High numbers (22-100%) of endophytic bacteria, isolated from root, stem, and leaf tissues, could tolerate elevated (1-3 mM) concentrations of K2CrO7. 16S rRNA gene sequence-based phylogenetic analysis showed that the 118 isolates obtained comprised of 17 operational taxonomic units affiliated with the proteobacterial genera Rhizobium (18%), Marinomonas (1%), Pseudomonas (16%), and Xanthomonas (7%) but also with members of Firmicutes genera, such as Bacillus (35%) and Salinococcus (3%). The novel isolates belonging to Salinococcus and Bacillus could tolerate high K2CrO7 concentrations (3 mM) and also showed elevated activity of chromate reductase. In addition, majority (%) of the endophytic isolates also showed production of indole-3-acetic acid. Taken together, our results indicate that the innate endophytic bacterial community assists plants in reducing heavy metal toxicity. PMID:26147743

  4. Effects of copper sulfate on seedlings of Prosopis pubescens (Screwbean mesquite)

    PubMed Central

    Zappala, Marian N.; Ellzey, Joanne T.; Bader, Julia; Peralta-Videa, Jose R.; Gardea-Torresdey, Jorge

    2013-01-01

    Phytoextraction is an established method of removal of heavy metals from contaminated soils worldwide. Phytoextraction is most efficient if local plants are used in the contaminated site. We propose that Prosopis pubescens (Screw bean mesquite) would be a successful phytoextractor of copper in our local soils. In order to determine the feasibility of using Screw bean mesquite, we utilized inductively coupled plasma-optical emission spectroscopy (ICP-OES) and elemental analysis to observe the uptake of copper and the effects on macro and micro nutrients within laboratory-grown seedlings. We have previously shown that pubescens is a hyperaccumulator of copper in soil-grown seedlings. Light and transmission electron microscopy demonstrated death of root cells and ultrastructural changes due to the presence of copper from 50 mg L-1 – 600 mg L-1. Ultrastructural changes included plasmolysis, starch accumulation, increased vacuolation and swollen chloroplasts with disarranged thylakoid membranes in cotyledons. Inductively coupled plasma-optical emission spectroscopy analyses of macro-and micro-nutrients revealed that the presence of copper sulfate in the growth mediium of Petri-dish grown Prosopis pubescens seedlings resulted in dramatic decreases of magnesium, potassium and phosphorus. At 500-600 mg L-1 of copper sulfate a substantial increase of sulfur was present in roots. PMID:24933900

  5. Catecholate-siderophore produced by As-resistant bacterium effectively dissolved FeAsO4 and promoted Pteris vittata growth.

    PubMed

    Liu, Xue; Yang, Guang-Mei; Guan, Dong-Xing; Ghosh, Piyasa; Ma, Lena Q

    2015-11-01

    The impact of siderophore produced by arsenic-resistant bacterium Pseudomonas PG12 on FeAsO4 dissolution and plant growth were examined. Arsenic-hyperaccumulator Pteris vittata was grown for 7 d in 0.2-strength Fe-free Hoagland solution containing FeAsO4 mineral and PG12-siderophore or fungal-siderophore desferrioxamine B (DFOB). Standard siderophore assays indicated that PG12-siderophore was catecholate-type. PG12-siderophore was more effective in promoting FeAsO4 dissolution, and Fe and As plant uptake than DFOB. Media soluble Fe and As in PG12 treatment were 34.6 and 3.07 ?M, 1.6- and 1.4-fold of that in DFOB. Plant Fe content increased from 2.93 to 6.24 g kg(-1) in the roots and As content increased from 14.3 to 78.5 mg kg(-1) in the fronds. Besides, P. vittata in PG12 treatment showed 2.6-times greater biomass than DFOB. While P. vittata fronds in PG12 treatment were dominated by AsIII, those in DFOB treatment were dominated by AsV (61-77%). This study showed that siderophore-producing arsenic-resistant rhizobacteria may have potential in enhancing phytoremediation of arsenic-contaminated soils. PMID:26247380

  6. Target or barrier? The cell wall of early- and later-diverging plants vs cadmium toxicity: differences in the response mechanisms.

    PubMed

    Parrotta, Luigi; Guerriero, Gea; Sergeant, Kjell; Cai, Giampiero; Hausman, Jean-Francois

    2015-01-01

    Increasing industrialization and urbanization result in emission of pollutants in the environment including toxic heavy metals, as cadmium and lead. Among the different heavy metals contaminating the environment, cadmium raises great concern, as it is ecotoxic and as such can heavily impact ecosystems. The cell wall is the first structure of plant cells to come in contact with heavy metals. Its composition, characterized by proteins, polysaccharides and in some instances lignin and other phenolic compounds, confers the ability to bind non-covalently and/or covalently heavy metals via functional groups. A strong body of evidence in the literature has shown the role of the cell wall in heavy metal response: it sequesters heavy metals, but at the same time its synthesis and composition can be severely affected. The present review analyzes the dual property of plant cell walls, i.e., barrier and target of heavy metals, by taking Cd toxicity as example. Following a summary of the known physiological and biochemical responses of plants to Cd, the review compares the wall-related mechanisms in early- and later-diverging land plants, by considering the diversity in cell wall composition. By doing so, common as well as unique response mechanisms to metal/cadmium toxicity are identified among plant phyla and discussed. After discussing the role of hyperaccumulators' cell walls as a particular case, the review concludes by considering important aspects for plant engineering. PMID:25814996

  7. Metallothionein 2 (SaMT2) from Sedum alfredii Hance Confers Increased Cd Tolerance and Accumulation in Yeast and Tobacco

    PubMed Central

    Zhang, Jie; Zhang, Min; Tian, Shengke; Lu, Lingli; Shohag, M. J. I.; Yang, Xiaoe

    2014-01-01

    Metallothioneins are cysteine-rich metal-binding proteins. In the present study, SaMT2, a type 2 metallothionein gene, was isolated from Cd/Zn co-hyperaccumulator Sedum alfredii Hance. SaMT2 encodes a putative peptide of 79 amino acid residues including two cysteine-rich domains. The transcript level of SaMT2 was higher in shoots than in roots of S. alfredii, and was significantly induced by Cd and Zn treatments. Yeast expression assay showed SaMT2 significantly enhanced Cd tolerance and accumulation in yeast. Ectopic expression of SaMT2 in tobacco enhanced Cd and Zn tolerance and accumulation in both shoots and roots of the transgenic plants. The transgenic plants had higher antioxidant enzyme activities and accumulated less H2O2 than wild-type plants under Cd and Zn treatment. Thus, SaMT2 could significantly enhance Cd and Zn tolerance and accumulation in transgenic tobacco plants by chelating metals and improving antioxidant system. PMID:25032704

  8. Long-term field phytoextraction of zinc/cadmium contaminated soil by Sedum plumbizincicola under different agronomic strategies.

    PubMed

    Deng, Lin; Li, Zhu; Wang, Jie; Liu, Hongyan; Li, Na; Wu, Longhua; Hu, Pengjie; Luo, Yongming; Christie, Peter

    2016-02-01

    In two long-term field experiments the zinc (Zn)/cadmium (Cd) hyperaccumulator Sedum plumbizincicola (S. plumbizincicola) was examined to optimize the phytoextraction of metal contaminated soil by two agronomic strategies of intercropping with maize (Zea mays) and plant densities. Soil total Zn and Cd concentrations decreased markedly after long-term phytoextraction. But shoot biomass and Cd and Zn concentrations showed no significant difference with increasing remediation time. In the intercropping experiment the phytoremediation efficiency in the treatment "S. plumbizincicola intercropped with maize" was higher than in S. plumbizincicola monocropping, and Cd concentrations of corn were below the maximum national limit. In the plant density experiment the phytoremediation efficiency increased with increasing plant density and 440,000 plants ha(-1) gave the maximum rate. These results indicated that S. plumbizincicola at an appropriate planting density and intercropped with maize can achieve high remediation efficiency to contaminated soil without affecting the cereal crop productivity. This cropping system combines adequate agricultural production with soil heavy metal phytoextraction. PMID:26445166

  9. Zinc and/or cadmium accumulation in Gynura pseudochina (L.) DC. studied in vitro and the effect on crude protein

    NASA Astrophysics Data System (ADS)

    Panitlertumpai, Natthawoot; Nakbanpote, Woranan; Sangdee, Aphidech; Thumanu, Kanjana; Nakai, Izumi; Hokura, Akiko

    2013-03-01

    Gynura pseudochina (L.) DC. is a zinc (Zn)/cadmium (Cd) hyperaccumulative plant. The aim of this study was to examine the tolerance of G. pseudochina (L.) DC. for Zn and/or Cd accumulation and protein expression. An in vitro tissue culture system was used to control the environment and effects of the microorganisms. Treatments with higher Zn and Cd concentrations increased chlorosis and the accumulation of metals in the root and shoot. Cd treatment at low levels induced the growth of the plant, and the translocation factor was high. A dual treatment with Cd and Zn decreased the metals' toxicity and demonstrated the plant's proclivity to accumulate Cd. The SDS-PAGE and FT-IR analyses showed the effect of the metals' toxicity on protein expression and secondary structure. Moreover, using XAFS techniques, it was demonstrated that treatment with a high Zn concentration (100 mg l-1) resulted in tetrahedral coordination with mixed S/O ligation in the protein extract as compared with Znsbnd O coordination in the protein extract from the control plant cultured in the presence of trace levels of Zn (0.04 mg l-1). This research suggested that G. pseudochina (L.) DC. had properties to tolerate a high Zn and Cd concentration, related to the sulphur proteins.

  10. Biosourced polymetallic catalysts: an efficient means to synthesize underexploited platform molecules from carbohydrates.

    PubMed

    Escande, Vincent; Olszewski, Tomasz K; Petit, Eddy; Grison, Claude

    2014-07-01

    Polymetallic hyperaccumulating plants growing on wastes from former mining activity were used as the starting material in the preparation of novel plant-based Lewis acid catalysts. The preparation of biosourced Lewis acid catalysts is a new way to make use of mining wastes. These catalysts were characterized by X-ray fluorescence, X-ray diffraction, inductively coupled plasma mass spectrometry, and direct infusion electrospray ionization mass spectrometry. These analyses revealed a complex composition of metal species, present mainly as polymetallic chlorides. The catalysts proved to be efficient and recyclable in a solid-state version of the Garcia Gonzalez reaction, which has been underexploited until now in efforts to use carbohydrates from biomass. This methodology was extended to various carbohydrates to obtain the corresponding polyhydroxyalkyl furans in 38-98% yield. These plant-based catalysts may be a better alternative to classical Lewis acid catalysts that were previously used for the Garcia Gonzalez reaction, such as ZnCl2 , FeCl3 , and CeCl3 , which are often unrecyclable, require aqueous treatments, or rely on metals, the current known reserves of which will be consumed in the coming decades. Moreover, the plant-based catalysts allowed novel control of the Garcia Gonzalez reaction, as two different products were obtained depending on the reaction conditions. PMID:25044809

  11. Tie-dyed2 Encodes a Callose Synthase That Functions in Vein Development and Affects Symplastic Trafficking within the Phloem of Maize Leaves12[C][W][OA

    PubMed Central

    Slewinski, Thomas L.; Baker, R. Frank; Stubert, Adam; Braun, David M.

    2012-01-01

    The tie-dyed2 (tdy2) mutant of maize (Zea mays) displays variegated green and yellow leaves. Intriguingly, the yellow leaf tissues hyperaccumulate starch and sucrose, the soluble sugar transported long distance through the phloem of veins. To determine the molecular basis for Tdy2 function, we cloned the gene and found that Tdy2 encodes a callose synthase. RNA in situ hybridizations revealed that in developing leaves, Tdy2 was most highly expressed in the vascular tissue. Comparative expression analysis with the vascular marker maize PINFORMED1a-yellow fluorescent protein confirmed that Tdy2 was expressed in developing vein tissues. To ascertain whether the defect in tdy2 leaves affected the movement of sucrose into the phloem or its long-distance transport, we performed radiolabeled and fluorescent dye tracer assays. The results showed that tdy2 yellow leaf regions were defective in phloem export but competent in long-distance transport. Furthermore, transmission electron microscopy of tdy2 yellow leaf regions showed incomplete vascular differentiation and implicated a defect in cell-to-cell solute movement between phloem companion cells and sieve elements. The disruption of sucrose movement in the phloem in tdy2 mutants provides evidence that the Tdy2 callose synthase functions in vascular maturation and that the vascular defects result in impaired symplastic trafficking into the phloem translocation stream. PMID:22932757

  12. Phytoremediation of wastewater with Limnocharis flava, Thalia geniculata and Typha latifolia in constructed wetlands.

    PubMed

    Anning, Alexander K; Korsah, Percy E; Addo-Fordjour, Patrick

    2013-01-01

    Phytoremediation is thought to be the most sustainable wastewater treatment option for developing countries. However, its application is often limited by unavailability of suitable candidate species. In the present study, the potentials of Limnocharis flava, Thalia geniculata and Typha latifolia for remediation of heavy metal contaminated wastewater with a constructed wetland system were evaluated. The wetland consisted of three treatment lines each planted with sufficient and equal number of a species. Duplicate plant and water samples were collected bi-monthly and analyzed for Fe, Cu, Zn, Pb, and Hg using the atomic absorption spectrophotometer over a six month period. Bioaccumulation rates generally increased over time and varied among plants for these metals, with Fe (456-1549 mg kg1 roots; 20-183 mg kg(-1) shoot) being the most sequestered and Pb (1.2-7.6 mg kg(-1) roots; 1.55-3.95 mg kg(-1) shoot) the least. Translocation factors differed among the species but generally remained stable over time. L flava showed potential for hyperaccumulating Hg. Removal efficiencies varied for the studied metals (approximately 20-77 %) and were generally related to metal uptake by the plants. These results demonstrate the suitability of the species for phytoremediation, and the usefulness of the technique as an option for improving irrigation water quality in Ghana. PMID:23488171

  13. [Mechanism of manganese binding to leaf cell wall of Phytolacca americana L].

    PubMed

    Xu, Xiang-Hua; Liu, Cui-Ying; Li, Ping; Lang, Man; Zhao, Xiao-Yan; Yang, Jian-Jun; Gong, Min

    2015-02-01

    Phytolacca americana L. (P. americana) is a manganese (Mn) hyperaccumulator and cell wall plays an important role in the accumulation and detoxicity of Mn. We studied the impact of pH and Mn initial concentration on the binding of Mn by the leaf cell wall of P. americana, and explored the binding mechanisms by Fourier Transform Infrared Spectroscopy (FTIR) and synchrotron-based X-ray Absorption Fine Structure (XAFS) Spectroscopy. The results show that the optimum pH of Mn bingding for the leaf cell wall is between 5 and 6. The adsorption behavior of leaf cell wall can be described by Langmuir equation (R2 = 0.978 5) and the maximum adsorption of Mn on the leaf cell wall is 62.50 ?mol x g(-1). Hydronyl and carbonyl groups are involved in the binding of Mn on the leaf cell wall. The Mn absorbed on the leaf cell wall is bonded by 6.3 oxygen around, and the bond length of Mn-O is 0.216 nm, which indicates the binding mechasnism of Mn to cell wall was inner-sphere complexation. PMID:26031102

  14. Transfer of heavy metals through terrestrial food webs: a review.

    PubMed

    Gall, Jillian E; Boyd, Robert S; Rajakaruna, Nishanta

    2015-04-01

    Heavy metals are released into the environment by both anthropogenic and natural sources. Highly reactive and often toxic at low concentrations, they may enter soils and groundwater, bioaccumulate in food webs, and adversely affect biota. Heavy metals also may remain in the environment for years, posing long-term risks to life well after point sources of heavy metal pollution have been removed. In this review, we compile studies of the community-level effects of heavy metal pollution, including heavy metal transfer from soils to plants, microbes, invertebrates, and to both small and large mammals (including humans). Many factors contribute to heavy metal accumulation in animals including behavior, physiology, and diet. Biotic effects of heavy metals are often quite different for essential and non-essential heavy metals, and vary depending on the specific metal involved. They also differ for adapted organisms, including metallophyte plants and heavy metal-tolerant insects, which occur in naturally high-metal habitats (such as serpentine soils) and have adaptations that allow them to tolerate exposure to relatively high concentrations of some heavy metals. Some metallophyte plants are hyperaccumulators of certain heavy metals and new technologies using them to clean metal-contaminated soil (phytoextraction) may offer economically attractive solutions to some metal pollution challenges. These new technologies provide incentive to catalog and protect the unique biodiversity of habitats that have naturally high levels of heavy metals. PMID:25800370

  15. Constitutively Elevated Salicylic Acid Levels Alter Photosynthesis and Oxidative State but Not Growth in Transgenic Populus[C][W

    PubMed Central

    Xue, Liang-Jiao; Guo, Wenbing; Yuan, Yinan; Anino, Edward O.; Nyamdari, Batbayar; Wilson, Mark C.; Frost, Christopher J.; Chen, Han-Yi; Babst, Benjamin A.; Harding, Scott A.; Tsai, Chung-Jui

    2013-01-01

    Salicylic acid (SA) has long been implicated in plant responses to oxidative stress. SA overproduction in Arabidopsis thaliana leads to dwarfism, making in planta assessment of SA effects difficult in this model system. We report that transgenic Populus tremula × alba expressing a bacterial SA synthase hyperaccumulated SA and SA conjugates without negative growth consequences. In the absence of stress, endogenously elevated SA elicited widespread metabolic and transcriptional changes that resembled those of wild-type plants exposed to oxidative stress-promoting heat treatments. Potential signaling and oxidative stress markers azelaic and gluconic acids as well as antioxidant chlorogenic acids were strongly coregulated with SA, while soluble sugars and other phenylpropanoids were inversely correlated. Photosynthetic responses to heat were attenuated in SA-overproducing plants. Network analysis identified potential drivers of SA-mediated transcriptome rewiring, including receptor-like kinases and WRKY transcription factors. Orthologs of Arabidopsis SA signaling components NON-EXPRESSOR OF PATHOGENESIS-RELATED GENES1 and thioredoxins were not represented. However, all members of the expanded Populus nucleoredoxin-1 family exhibited increased expression and increased network connectivity in SA-overproducing Populus, suggesting a previously undescribed role in SA-mediated redox regulation. The SA response in Populus involved a reprogramming of carbon uptake and partitioning during stress that is compatible with constitutive chemical defense and sustained growth, contrasting with the SA response in Arabidopsis, which is transient and compromises growth if sustained. PMID:23903318

  16. Sub-cellular metal imaging identifies dynamic sites of Cu accumulation in Chlamydomonas

    PubMed Central

    Hong-Hermesdorf, Anne; Miethke, Marcus; Gallaher, Sean D; Kropat, Janette; Dodani, Sheel C; Chan, Jefferson; Barupala, Dulmini; Domaille, Dylan W; Shirasaki, Dyna I; Loo, Joseph A; Weber, Peter K; Pett-Ridge, Jennifer; Stemmler, Timothy L; Chang, Christopher J; Merchant, Sabeeha S

    2014-01-01

    We identified a Cu accumulating structure with a dynamic role in intracellular Cu homeostasis. During Zn limitation, Chlamydomonas reinhardtii hyperaccumulated Cu, dependent on the nutritional Cu sensor CRR1, but was functionally Cu-deficient. Visualization of intracellular Cu revealed major Cu accumulation sites coincident with electron-dense structures that stained positive for low pH and polyphosphate, suggesting that they are lysosome-related organelles. NanoSIMS showed colocalization of Ca and Cu, and X-ray absorption spectroscopy (XAS) was consistent with Cu+ accumulation in an ordered structure. Zn resupply restored Cu homeostasis concomitant with reduced abundance of these structures. Cu isotope labeling demonstrated that sequestered Cu+ became bio-available for the synthesis of plastocyanin, and transcriptome profiling indicated that mobilized Cu became visible to CRR1. Cu trafficking to intracellular accumulation sites may be a strategy for preventing protein mis-metallation during Zn deficiency and enabling efficient cuproprotein (re)-metallation upon Zn resupply. PMID:25344811

  17. Effects of Phosphate on Arsenate Uptake and Translocation in Nonmetallicolous and Metallicolous Populations of Pteris Vittata L. Under Solution Culture.

    PubMed

    Wu, Fuyong; Wu, Shengchun; Deng, Dan; Wong, Ming Hung

    2015-01-01

    An arsenic hyperaccumulator, Pteris vittata L., is common in nature and could occur either on As-contaminated soils or on uncontaminated soils. However, it is not clear whether phosphate transporter play similar roles in As uptake and translocation in nonmetallicolous and metallicolous populations of P. vittata. Five populations were used to investigate effects of phosphate on arsenate uptake and translocation in the plants growing in 1.2 L 20% modified Hoagland's nutrient solution containing either 100 ?M phosphate or no phosphate and 10 ?M arsenate for 1, 2, 6, 12, 24 h, respectively. The results showed that the nonmetallicolous populations accumulated apparently more As in their fronds and roots than the metallicolous populations at both P supply levels. Phosphate significantly (P < 0.01) decreased frond and root concentrations of As during short time solution culture. In addition, the effects of phosphate on As translocation in P. vittata varied among different time-points during time-course hydroponics (1-24 h). The present results indicated that the inhibitory effect of phosphate on arsenate uptake was larger in the three nonmetallicolous populations than those in the two metallicolous populations of P. vittata. PMID:26083716

  18. Heavy metal removal and crude bio-oil upgrading from Sedum plumbizincicola harvest using hydrothermal upgrading process.

    PubMed

    Yang, Jian-guang

    2010-10-01

    The main aim of this study was to separate heavy metals and yield crude bio-oil from a heavy metals hyperaccumulator harvest, Sedum plumbizincicola, through hydrothermal upgrading process. Parameters such as granularity, temperature, pressure, and duration were examined for their effect on the removal efficiency of heavy metals and upgrading efficacy of crude bio-oil. Maximum heavy metal removal efficiency of >99% and crude bio-oil upgrading efficiency of >63% were attained with an 18 mesh (1 mm) granularity, and 22.1 MPa at 370 degrees C in the presence of 10 mg/L additives for 60 s. Under these optimized conditions, an oil phase (mostly composed of phenolic hydrocarbons and derivatives), a water phase raffinate containing Zn2+ (0.39 g/L), Pb2+ (0.10 g/L), Cu2+ (0.16 g/L), and a solid phase (the hydrothermal upgrading residue, which completely satisfies the limit set by China legislation related to biosolids disposal, were obtained). PMID:20578290

  19. Target or barrier? The cell wall of early- and later-diverging plants vs cadmium toxicity: differences in the response mechanisms

    PubMed Central

    Parrotta, Luigi; Guerriero, Gea; Sergeant, Kjell; Cai, Giampiero; Hausman, Jean-Francois

    2015-01-01

    Increasing industrialization and urbanization result in emission of pollutants in the environment including toxic heavy metals, as cadmium and lead. Among the different heavy metals contaminating the environment, cadmium raises great concern, as it is ecotoxic and as such can heavily impact ecosystems. The cell wall is the first structure of plant cells to come in contact with heavy metals. Its composition, characterized by proteins, polysaccharides and in some instances lignin and other phenolic compounds, confers the ability to bind non-covalently and/or covalently heavy metals via functional groups. A strong body of evidence in the literature has shown the role of the cell wall in heavy metal response: it sequesters heavy metals, but at the same time its synthesis and composition can be severely affected. The present review analyzes the dual property of plant cell walls, i.e., barrier and target of heavy metals, by taking Cd toxicity as example. Following a summary of the known physiological and biochemical responses of plants to Cd, the review compares the wall-related mechanisms in early- and later-diverging land plants, by considering the diversity in cell wall composition. By doing so, common as well as unique response mechanisms to metal/cadmium toxicity are identified among plant phyla and discussed. After discussing the role of hyperaccumulators’ cell walls as a particular case, the review concludes by considering important aspects for plant engineering. PMID:25814996

  20. Compromised virus-induced gene silencing in RDR6-deficient plants.

    PubMed

    Vaistij, Fabián E; Jones, Louise

    2009-03-01

    RNA silencing in plants serves as a potent antiviral defense mechanism through the action of small interfering RNAs (siRNAs), which direct RNA degradation. siRNAs can be derived directly from the viral genome or via the action of host-encoded RNA-dependent RNA polymerases (RDRs). Plant genomes encode multiple RDRs, and it has been demonstrated that plants defective for RDR6 hyperaccumulate several classes of virus. In this study, we compared the effectiveness of virus-induced gene silencing (VIGS) and RNA-directed DNA methylation (RdDM) in wild-type and RDR6-deficient Nicotiana benthamiana plants. For the potexvirus Potato virus X (PVX) and the potyvirus Plum pox virus (PPV), the efficiency of both VIGS and RdDM were compromised in RDR6-defective plants despite accumulating high levels of viral siRNAs similar to infection of wild-type plants. The reduced efficiency of VIGS and RdDM was unrelated to the size class of siRNA produced and, at least for PVX, was not dependent on the presence of the virus-encoded silencing suppressor protein, 25K. We suggest that primary siRNAs produced from PVX and PPV in the absence of RDR6 may not be good effectors of silencing and that RDR6 is required to produce secondary siRNAs that drive a more effective antiviral response. PMID:19129420

  1. Influence of Rapeseed Cake on Heavy Metal Uptake by a Subsequent Rice Crop After Phytoextraction Using Sedum plumbizincicola.

    PubMed

    Zhou, Liqiang; Wu, Longhua; Li, Zhu; Yang, Bingfan; Yin, Bin; Luo, Yongming; Christie, Peter

    2015-01-01

    A glasshouse pot experiment was conducted to study the effects of phytoextraction by Sedum plumbizincicola and application of rapeseed cake (RSC) on heavy metal accumulation by a subsequent rice (Oryza sativa L.) crop in a contaminated paddy soil collected from east China. After phytoextraction by S. plumbizincicola the soil and brown rice Cd concentrations effectively declined. After phytoextraction, RSC application reduced brown rice Cd concentrations in the subsequent rice crop to 0.23-0.28 mg kg(-1), almost down to the standard limit (0.2 mg kg(-1)). After phytoextraction and then application of RSC, the soil solution pH, dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) concentrations increased during early stages of rice growth resulting directly and indirectly in lowering the bioavailability of the heavy metals. Thus the grain yield of the subsequent rice crop increased and the heavy metals in the brown rice declined significantly. In this contaminated acid soil, growing the hyperaccumulator S. plumbizincicola and rice in rotation together with RSC application may therefore be regarded as a viable strategy for safe grain production and bioremediation. PMID:25174427

  2. Ca(2+) and CaM are involved in Al(3+) pretreatment-promoted fluoride accumulation in tea plants (Camellia sinesis L.).

    PubMed

    Zhang, Xian-Chen; Gao, Hong-Jian; Wu, Hong-Hong; Yang, Tian-Yuan; Zhang, Zheng-Zhu; Mao, Jing-Dong; Wan, Xiao-Chun

    2015-11-01

    Tea plant (Camellia sinensis (L.) O. kuntze) is known to be a fluoride (F) and aluminum (Al(3+)) hyper-accumulator. Previous study showed that pre-treatment of Al(3+) caused a significant increase of F accumulation in tea plants. However, less is known about the intricate network of Al(3+) promoted F accumulation in tea plants. In this study, the involvement of endogenous Ca(2+) and CaM in Al(3+) pretreatment-promoted F accumulation in tea plants was investigated. Our results showed that Al(3+) induced the inverse change of intracellular Ca(2+) fluorescence intensity and stimulated Ca(2+) trans-membrane transport in the mature zone of tea root. Also, a link between internal Ca(2+) and CaM was found in tea roots under the presence of Al(3+). In order to investigate whether Ca(2+) and CaM were related to F accumulation promoted by Al(3+) pretreatment, Ca(2+) chelator EGTA and CaM antagonists CPZ and TFP were used. EGTA, CPZ, and TFP pretreatment inhibited Al(3+)-induced increase of Ca(2+) fluorescence intensity and CaM content in tea roots, and also significantly reduced Al(3+)-promoted F accumulation in tea plants. Taken together, our results suggested that the endogenous Ca(2+) and CaM are involved in Al(3+) pretreatment-promoted F accumulation in tea roots. PMID:26318146

  3. Phosphorus solubilization and plant growth enhancement by arsenic-resistant bacteria.

    PubMed

    Ghosh, Piyasa; Rathinasabapathi, Bala; Ma, Lena Q

    2015-09-01

    Phosphorus is an essential nutrient, which is limited in most soils. The P solubilization and growth enhancement ability of seven arsenic-resistant bacteria (ARB), which were isolated from arsenic hyperaccumulator Pteris vittata, was investigated. Siderophore-producing ARB (PG4, 5, 6, 9, 10, 12 and 16) were effective in solubilizing P from inorganic minerals FePO4 and phosphate rock, and organic phytate. To reduce bacterial P uptake we used filter-sterilized Hoagland medium containing siderophores or phytase produced by PG12 or PG6 to grow tomato plants supplied with FePO4 or phytate. To confirm that siderophores were responsible for P release, we compared the mutants of siderophore-producing bacterium Pseudomonas fluorescens Pf5 (PchA) impaired in siderophore production with the wild type and test strains. After 7d of growth, mutant PchA solubilized 10-times less P than strain PG12, which increased tomato root biomass by 1.7 times. For phytate solubilization by PG6, tomato shoot biomass increased by 44% than control bacterium Pseudomonas chlororaphis. P solubilization by ARB from P. vittata may be useful in enhancing plant growth and nutrition in other crop plants. PMID:25880602

  4. Co-treatment of landfill leachate and municipal wastewater using the ZELIAC/zeolite constructed wetland system.

    PubMed

    Mojiri, Amin; Ziyang, Lou; Tajuddin, Ramlah Mohd; Farraji, Hossein; Alifar, Nafiseh

    2016-01-15

    Constructed wetland (CW) is a low-cost alternative technology to treat wastewater. This study was conducted to co-treat landfill leachate and municipal wastewater by using a CW system. Typha domingensis was transplanted to CW, which contains two substrate layers of adsorbents, namely, ZELIAC and zeolite. Response surface methodology and central composite design have been utilized to analyze experimental data. Contact time (h) and leachate-to-wastewater mixing ratio (%; v/v) were considered as independent variables. Colour, COD, ammonia, nickel, and cadmium contents were used as dependent variables. At optimum contact time (50.2 h) and leachate-to-wastewater mixing ratio (20.0%), removal efficiencies of colour, COD, ammonia, nickel, and cadmium contents were 90.3%, 86.7%, 99.2%, 86.0%, and 87.1%, respectively. The accumulation of Ni and Cd in the roots and shoots of T. domingensis was also monitored. Translocation factor (TF) was >1 in several runs; thus, Typha is classified as a hyper-accumulator plant. PMID:26496842

  5. A new method for antimony speciation in plant biomass and nutrient media using anion exchange cartridge.

    PubMed

    Tisarum, Rujira; Ren, Jing-Hua; Dong, Xiaoling; Chen, Hao; Lessl, Jason T; Ma, Lena Q

    2015-11-01

    A selective separation method based on anion exchange cartridge was developed to determine antimony (Sb) speciation in biological matrices by graphite furnace atomic absorption spectrophotometry (GFAAS). The selectivity of the cartridge towards antimonite [Sb(III)] and antimonate [Sb(V)] reversed in the presence of deionized (DI) water and 2mM citric acid. While Sb(V) was retained by the cartridge in DI water, Sb(III) was retained in citric acid media. At pH 6, Sb(III) and Sb(V) formed Sb(III)- and Sb(V)-citrate complexes, but the cartridge had higher affinity towards the Sb(III)-citrate complex. Separation of Sb(III) was tested at various concentrations in fresh and spent growth media and plant tissues. Our results showed that cartridge-based Sb speciation was successful in plant tissues, which was confirmed by HPLC-ICP-MS. The cartridge retained Sb(III) and showed 92-104% Sb(V) recovery from arsenic hyperaccumulator Pteris vittata roots treated with Sb(III) and Sb(V). The cartridge procedure is an effective alternative for Sb speciation, offering low cost, reproducible results, and simple Sb analysis using GFAAS. PMID:26452943

  6. Effects of extended growth periods on subcellular distribution, chemical forms, and the translocation of cadmium in Impatiens walleriana.

    PubMed

    Lai, Hung-Yu; Cai, Ming-Cyuan

    2016-03-01

    Impatiens walleriana plants accumulate sufficiently high concentrations of cadmium (Cd) for this species to be considered a potential Cd hyperaccumulator. Rooted cuttings were grown hydroponically for 25 and 50 days in solutions spiked with various Cd concentrations. The subcellular distribution and chemical forms of Cd in different organs were analyzed, and its upward translocation was also assessed. The plants accumulated large amounts of Cd; the Cd concentration in the roots and shoots reached 120-1900 and 60-1600 mg/kg, respectively. Regardless of the growth period, the Cd accumulated in the roots was primarily compartmentalized in the soluble fraction or ethanol and deionized water extractable chemical forms with high migration abilities. Translocation to the shoots was followed by an association of Cd mainly in the cell wall or with pectate and protein. The roots' Cd showed a high migration capacity for predicting the shoots' Cd concentrations. Different exposure periods significantly affected the subcellular distribution of Cd in the stems, and thus the upward translocation. PMID:26247535

  7. Cadmium removal by Euglena gracilis is enhanced under anaerobic growth conditions.

    PubMed

    Santiago-Martínez, M Geovanni; Lira-Silva, Elizabeth; Encalada, Rusely; Pineda, Erika; Gallardo-Pérez, Juan Carlos; Zepeda-Rodriguez, Armando; Moreno-Sánchez, Rafael; Saavedra, Emma; Jasso-Chávez, Ricardo

    2015-05-15

    The facultative protist Euglena gracilis, a heavy metal hyper-accumulator, was grown under photo-heterotrophic and extreme conditions (acidic pH, anaerobiosis and with Cd(2+)) and biochemically characterized. High biomass (8.5×10(6)cellsmL(-1)) was reached after 10 days of culture. Under anaerobiosis, photosynthetic activity built up a microaerophilic environment of 0.7% O?, which was sufficient to allow mitochondrial respiratory activity: glutamate and malate were fully consumed, whereas 25-33% of the added glucose was consumed. In anaerobic cells, photosynthesis but not respiration was activated by Cd(2+) which induced higher oxidative stress. Malondialdehyde (MDA) levels were 20 times lower in control cells under anaerobiosis than in aerobiosis, although Cd(2+) induced a higher MDA production. Cd(2+) stress induced increased contents of chelating thiols (cysteine, glutathione and phytochelatins) and polyphosphate. Biosorption (90%) and intracellular accumulation (30%) were the mechanisms by which anaerobic cells removed Cd(2+) from medium, which was 36% higher versus aerobic cells. The present study indicated that E. gracilis has the ability to remove Cd(2+) under anaerobic conditions, which might be advantageous for metal removal in sediments from polluted water bodies or bioreactors, where the O? concentration is particularly low. PMID:25698571

  8. Progress toward clonable inorganic nanoparticles

    NASA Astrophysics Data System (ADS)

    Ni, Thomas W.; Staicu, Lucian C.; Nemeth, Richard S.; Schwartz, Cindi L.; Crawford, David; Seligman, Jeffrey D.; Hunter, William J.; Pilon-Smits, Elizabeth A. H.; Ackerson, Christopher J.

    2015-10-01

    Pseudomonas moraviensis stanleyae was recently isolated from the roots of the selenium (Se) hyperaccumulator plant Stanleya pinnata. This bacterium tolerates normally lethal concentrations of SeO32- in liquid culture, where it also produces Se nanoparticles. Structure and cellular ultrastructure of the Se nanoparticles as determined by cellular electron tomography shows the nanoparticles as intracellular, of narrow dispersity, symmetrically irregular and without any observable membrane or structured protein shell. Protein mass spectrometry of a fractionated soluble cytosolic material with selenite reducing capability identified nitrite reductase and glutathione reductase homologues as NADPH dependent candidate enzymes for the reduction of selenite to zerovalent Se nanoparticles. In vitro experiments with commercially sourced glutathione reductase revealed that the enzyme can reduce SeO32- (selenite) to Se nanoparticles in an NADPH-dependent process. The disappearance of the enzyme as determined by protein assay during nanoparticle formation suggests that glutathione reductase is associated with or possibly entombed in the nanoparticles whose formation it catalyzes. Chemically dissolving the nanoparticles releases the enzyme. The size of the nanoparticles varies with SeO32- concentration, varying in size form 5 nm diameter when formed at 1.0 ?M [SeO32-] to 50 nm maximum diameter when formed at 100 ?M [SeO32-]. In aggregate, we suggest that glutathione reductase possesses the key attributes of a clonable nanoparticle system: ion reduction, nanoparticle retention and size control of the nanoparticle at the enzyme site.Pseudomonas moraviensis stanleyae was recently isolated from the roots of the selenium (Se) hyperaccumulator plant Stanleya pinnata. This bacterium tolerates normally lethal concentrations of SeO32- in liquid culture, where it also produces Se nanoparticles. Structure and cellular ultrastructure of the Se nanoparticles as determined by cellular electron tomography shows the nanoparticles as intracellular, of narrow dispersity, symmetrically irregular and without any observable membrane or structured protein shell. Protein mass spectrometry of a fractionated soluble cytosolic material with selenite reducing capability identified nitrite reductase and glutathione reductase homologues as NADPH dependent candidate enzymes for the reduction of selenite to zerovalent Se nanoparticles. In vitro experiments with commercially sourced glutathione reductase revealed that the enzyme can reduce SeO32- (selenite) to Se nanoparticles in an NADPH-dependent process. The disappearance of the enzyme as determined by protein assay during nanoparticle formation suggests that glutathione reductase is associated with or possibly entombed in the nanoparticles whose formation it catalyzes. Chemically dissolving the nanoparticles releases the enzyme. The size of the nanoparticles varies with SeO32- concentration, varying in size form 5 nm diameter when formed at 1.0 ?M [SeO32-] to 50 nm maximum diameter when formed at 100 ?M [SeO32-]. In aggregate, we suggest that glutathione reductase possesses the key attributes of a clonable nanoparticle system: ion reduction, nanoparticle retention and size control of the nanoparticle at the enzyme site. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04097c

  9. Overaccumulation of ?-Glutamylcysteine in a Jasmonate-Hypersensitive Arabidopsis Mutant Causes Jasmonate-Dependent Growth Inhibition1[OPEN

    PubMed Central

    Wei, Hsin-Ho; Rowe, Martha; Riethoven, Jean-Jack M.; Grove, Ryan; Adamec, Jiri; Jikumaru, Yusuke; Staswick, Paul

    2015-01-01

    Glutathione (GSH) is essential for many aspects of plant biology and is associated with jasmonate signaling in stress responses. We characterized an Arabidopsis (Arabidopsis thaliana) jasmonate-hypersensitive mutant (jah2) with seedling root growth 100-fold more sensitive to inhibition by the hormone jasmonyl-isoleucine than the wild type. Genetic mapping and genome sequencing determined that the mutation is in intron 6 of GLUTATHIONE SYNTHETASE2, encoding the enzyme that converts ?-glutamylcysteine (?-EC) to GSH. The level of GSH in jah2 was 71% of the wild type, while the phytoalexin-deficient2-1 (pad2-1) mutant, defective in GSH1 and having only 27% of wild-type GSH level, was not jasmonate hypersensitive. Growth defects for jah2, but not pad2, were also seen in plants grown to maturity. Surprisingly, all phenotypes in the jah2 pad2-1 double mutant were weaker than in jah2. Quantification of ?-EC indicated these defects result from hyperaccumulation of this GSH precursor by 294- and 65-fold in jah2 and the double mutant, respectively. ?-EC reportedly partially substitutes for loss of GSH, but growth inhibition seen here was likely not due to an excess of total glutathione plus ?-EC because their sum in jah2 pad2-1 was only 16% greater than in the wild type. Further, the jah2 phenotypes were lost in a jasmonic acid biosynthesis mutant background, indicating the effect of ?-EC is mediated through jasmonate signaling and not as a direct result of perturbed redox status. PMID:26282239

  10. Overexpression of the bZIP transcription factor OsbZIP79 suppresses the production of diterpenoid phytoalexin in rice cells.

    PubMed

    Miyamoto, Koji; Nishizawa, Yoko; Minami, Eiichi; Nojiri, Hideaki; Yamane, Hisakazu; Okada, Kazunori

    2014-09-16

    Phytoalexins are antimicrobial specialised metabolites that are produced by plants in response to pathogen attack. Momilactones and phytocassanes are major diterpenoid phytoalexins in rice that are synthesised from geranylgeranyl diphosphate that is derived from the methylerythritol phosphate (MEP) pathway. We have previously reported that rice cells overexpressing the basic leucine zipper (bZIP) transcription factor OsTGAP1 exhibit a hyperaccumulation of momilactones and phytocassanes, with hyperinductive expression of momilactone and phytocassane biosynthetic genes and MEP pathway genes, upon response to a chitin oligosaccharide elicitor. For a better understanding of OsTGAP1-mediated regulation of diterpenoid phytoalexin production, we identified OsTGAP1-interacting proteins using yeast two-hybrid screening. Among the OsTGAP1-interacting protein candidates, a TGA factor OsbZIP79 was investigated to verify its physical interaction with OsTGAP1 and involvement in the regulation of phytoalexin production. An in vitro pull-down assay demonstrated that OsTGAP1 and OsbZIP79 exhibited a heterodimeric as well as a homodimeric interaction. A bimolecular fluorescence complementation analysis also showed the interaction between OsTGAP1 and OsbZIP79 in vivo. Intriguingly, whereas OsbZIP79 transactivation activity was observed in a transient reporter assay, the overexpression of OsbZIP79 resulted in suppression of the elicitor-inducible expression of diterpenoid phytoalexin biosynthetic genes, and thus caused a decrease in the accumulation of phytoalexin in rice cells. These results suggest that OsbZIP79 functions as a negative regulator of phytoalexin production triggered by a chitin oligosaccharide elicitor in rice cells, although it remains open under which conditions OsbZIP79 can work with OsTGAP1. PMID:25462074

  11. The zinc homeostasis network of land plants.

    PubMed

    Sinclair, Scott Aleksander; Krämer, Ute

    2012-09-01

    The use of the essential element zinc (Zn) in the biochemistry of land plants is widespread, and thus comparable to that in other eukaryotes. Plants have evolved the ability to adjust to vast fluctuations in external Zn supply, and they can store considerable amounts of Zn inside cell vacuoles. Moreover, among plants there is overwhelming, but yet little explored, natural genetic diversity that phenotypically affects Zn homeostasis. This results in the ability of specific races or species to thrive in different soils ranging from extremely Zn-deficient to highly Zn-polluted. Zn homeostasis is maintained by a tightly regulated network of low-molecular-weight ligands, membrane transport and Zn-binding proteins, as well as regulators. Here we review Zn homeostasis of land plants largely based on the model plant Arabidopsis thaliana, for which our molecular understanding is most developed at present. There is some evidence for substantial conservation of Zn homeostasis networks among land pants, and this review can serve as a reference for future comparisons. Major progress has recently been made in our understanding of the regulation of transcriptional Zn deficiency responses and the role of the low-molecular-weight chelator nicotianamine in plant Zn homeostasis. Moreover, we have begun to understand how iron (Fe) and Zn homeostasis interact as a consequence of the chemical similarity between their divalent cations and the lack of specificity of the major root iron uptake transporter IRT1. The molecular analysis of Zn-hyperaccumulating plants reveals how metal homeostasis networks can be effectively modified. These insights are important for sustainable bio-fortification approaches. This article is part of a Special Issue entitled: Cell Biology of Metals. PMID:22626733

  12. Trichoderma reesei FS10-C enhances phytoremediation of Cd-contaminated soil by Sedum plumbizincicola and associated soil microbial activities

    PubMed Central

    Teng, Ying; Luo, Yang; Ma, Wenting; Zhu, Lingjia; Ren, Wenjie; Luo, Yongming; Christie, Peter; Li, Zhengao

    2015-01-01

    This study aimed to explore the effects of Trichoderma reesei FS10-C on the phytoremediation of Cd-contaminated soil by the hyperaccumulator Sedum plumbizincicola and on soil fertility. The Cd tolerance of T. reesei FS10-C was characterized and then a pot experiment was conducted to investigate the growth and Cd uptake of S. plumbizincicola with the addition of inoculation agents in the presence and absence of T. reesei FS10-C. The results indicated that FS10-C possessed high Cd resistance (up to 300 mg L-1). All inoculation agents investigated enhanced plant shoot biomass by 6–53% of fresh weight and 16–61% of dry weight and Cd uptake by the shoots by 10–53% compared with the control. All inoculation agents also played critical roles in increasing soil microbial biomass and microbial activities (such as biomass C, dehydrogenase activity and fluorescein diacetate hydrolysis activity). Two inoculation agents accompanied by FS10-C were also superior to the inoculation agents, indicating that T. reesei FS10-C was effective in enhancing both Cd phytoremediation by S. plumbizincicola and soil fertility. Furthermore, solid fermentation powder of FS10-C showed the greatest capacity to enhance plant growth, Cd uptake, nutrient release, microbial biomass and activities, as indicated by its superior ability to promote colonization by Trichoderma. The solid fermentation powder of FS10-C might serve as a suitable inoculation agent for T. reesei FS10-C to enhance both the phytoremediation efficiency of Cd-contaminated soil and soil fertility. PMID:26113858

  13. Fate of cadmium in the rhizosphere of Arabidopsis halleri grown in a contaminated dredged sediment.

    PubMed

    Huguet, Séphanie; Isaure, Marie-Pierre; Bert, Valérie; Laboudigue, Agnès; Proux, Olivier; Flank, Anne-Marie; Vantelon, Delphine; Sarret, Géraldine

    2015-12-01

    In regions impacted by mining and smelting activities, dredged sediments are often contaminated with metals. Phytotechnologies could be used for their management, but more knowledge on the speciation of metals in the sediment and on their fate after colonization by plant roots is needed. This work was focused on a dredged sediment from the Scarpe river (North of France), contaminated with Zn and Cd. Zn, Cd hyperaccumulating plants Arabidopsis halleri from metallicolous and non-metallicolous origin were grown on the sediment for five months in a pot experiment. The nature and extent of the modifications in Cd speciation with or without plant were determined by electron microscopy, micro X-ray fluorescence and bulk and micro X-ray absorption spectroscopy. In addition, changes in Cd exchangeable and bioavailable pools were evaluated, and Cd content in leachates was measured. Finally, Cd plant uptake and plant growth parameters were monitored. In the original sediment, Cd was present as a mixed Zn, Cd, Fe sulfide. After five months, although pots still contained reduced sulfur, Cd-bearing sulfides were totally oxidized in vegetated pots, whereas a minor fraction (8%) was still present in non-vegetated ones. Secondary species included Cd bound to O-containing groups of organic matter and Cd phosphates. Cd exchangeability and bioavailability were relatively low and did not increase during changes in Cd speciation, suggesting that Cd released by sulfide oxidation was readily taken up with strong interactions with organic matter and phosphate ligands. Thus, the composition of the sediment, the oxic conditions and the rhizospheric activity (regardless of the plant origin) created favorable conditions for Cd stabilization. However, it should be kept in mind that returning to anoxic conditions may change Cd speciation, so the species formed cannot be considered as stable on the long term. PMID:26233782

  14. Growth responses and cadmium accumulation of Mirabilis jalapa L. under interaction between cadmium and phosphorus.

    PubMed

    Yu, Zhiguo; Zhou, Qixing

    2009-08-15

    Based on the identification of Mirabilis jalapa L. as a new Cd-hyperaccumulating ornamental, the growth response of the plant to interaction between cadmium (Cd) and phosphorus (P), its effect on the Cd accumulation in the species and relevant mechanisms were further investigated by the pot-culture experiment with chemical analyses and the X-ray absorption near edge structure spectra (XANES). It showed that the leaf, shoot and root biomass (as dry matter) increased with an increase in P supplies from 20 to 100 mg kg(-1) at various tested Cd levels except 10 mg kg(-1). The Cd accumulation in the leaves and shoots significantly decreased with increasing P concentrations from 20 to 500 mg kg(-1) at the Cd concentrations from 10 to 50 mg kg(-1), except the Cd level at 100 mg kg(-1). It was also found that the translocation factor of Cd in M. jalapa L. reached the maximum at different tested Cd levels when the concentration of added P was 100 mg kg(-1), but the bioaccumulation factor of Cd decreased with increasing P. This changing law may be responsible for the mechanism of P immobilizing Cd. The investigation using the P-K edge XANES showed the spectra of adsorbed phosphate in the shoots exhibited a stronger white-line peak than that in the leaves and roots, and the oscillation near 2165eV was more intense. Besides, the P-K edge XANES spectra for M. jalapa L. indicated P may exist as Cd-phosphate. Thus, it can be inferred that the addition of P at appropriate contents may be a useful approach to enhance the plant growth and to immobilize Cd in the Cd-contaminated soil. Furthermore, P and Cd may form a deposit in plants to tolerate Cd toxicity for reducing the degree of the structural damage of the plant. PMID:19179005

  15. A chemical potentiator of copper-accumulation used to investigate the iron-regulons of Saccharomyces cerevisiae

    PubMed Central

    Foster, Andrew W; Dainty, Samantha J; Patterson, Carl J; Pohl, Ehmke; Blackburn, Hannah; Wilson, Clare; Hess, Corinna R; Rutherford, Julian C; Quaranta, Laura; Corran, Andy; Robinson, Nigel J

    2014-01-01

    The extreme resistance of Saccharomyces cerevisiae to copper is overcome by 2-(6-benzyl-2-pyridyl)quinazoline (BPQ), providing a chemical-biology tool which has been exploited in two lines of discovery. First, BPQ is shown to form a red (BPQ)2Cu(I) complex and promote Ctr1-independent copper-accumulation in whole cells and in mitochondria isolated from treated cells. Multiple phenotypes, including loss of aconitase activity, are consistent with copper-BPQ mediated damage to mitochondrial iron–sulphur clusters. Thus, a biochemical basis of copper-toxicity in S. cerevisiae is analogous to other organisms. Second, iron regulons controlled by Aft1/2, Cth2 and Yap5 that respond to mitochondrial iron–sulphur cluster status are modulated by copper-BPQ causing iron hyper-accumulation via upregulated iron-import. Comparison of copper-BPQ treated, untreated and copper-only treated wild-type and fra2? by RNA-seq has uncovered a new candidate Aft1 target-gene (LSO1) and paralogous non-target (LSO2), plus nine putative Cth2 target-transcripts. Two lines of evidence confirm that Fra2 dominates basal repression of the Aft1/2 regulons in iron-replete cultures. Fra2-independent control of these regulons is also observed but CTH2 itself appears to be atypically Fra2-dependent. However, control of Cth2-target transcripts which is independent of CTH2 transcript abundance or of Fra2, is also quantified. Use of copper-BPQ supports a substantial contribution of metabolite repression to iron-regulation. PMID:24895027

  16. Phytoremediation--a novel and promising approach for environmental clean-up.

    PubMed

    Suresh, B; Ravishankar, G A

    2004-01-01

    Phytoremediation is an eco friendly approach for remediation of contaminated soil and water using plants. Phytoremediation is comprised of two components, one by the root colonizing microbes and the other by plants themselves, which degrade the toxic compounds to further non-toxic metabolites. Various compounds, viz. organic compounds, xenobiotics, pesticides and heavy metals, are among the contaminants that can be effectively remediated by plants. Plant cell cultures, hairy roots and algae have been studied for their ability to degrade a number of contaminants. They exhibit various enzymatic activities for degradation of xenobiotics, viz. dehalogenation, denitrification leading to breakdown of complex compounds to simple and non-toxic products. Plants and algae also have the ability to hyper accumulate various heavy metals by the action of phytochelatins and metallothioneins forming complexes with heavy metals and translocate them into vacuoles. Molecular cloning and expression of heavy metal accumulator genes and xenobiotic degrading enzyme coding genes resulted in enhanced remediation rates, which will be helpful in making the process for large-scale application to remediate vast areas of contaminated soils. A few companies worldwide are also working on this aspect of bioremediation, mainly by transgenic plants to replace expensive physical or chemical remediation techniques. Selection and testing multiple hyperaccumulator plants, protein engineering ofphytochelatin and membrane transporter genes and their expression would enhance the rate of phytoremediation, making this process a successful one for bioremediation of environmental contamination. Recent years have seen major investments in the R&D, which have also resulted in competition of filing patents by several companies for economic gains. The details of science & technology related to phytoremediation have been discussed with a focus on future trends and prospects of global relevance. PMID:15493528

  17. Plants accumulating heavy metals in the Danube River wetlands

    PubMed Central

    2013-01-01

    Background We present herein our results regarding the accumulation of four heavy metals (copper, cadmium, lead, and zinc) in four aquatic species plants (Ceratophyllum demersum, Potamogeton pectinatus, Potamogeton lucens, Potamogeton perfoliatus) collected from the Danube River, South-Western part of Romania and their possible use as indicators of aquatic ecosystems pollution with heavy metals. Methods Elements concentration from the vegetal material was determined through Inductively Coupled Plasma – Mass Spectrometry. Results The species were chosen based on their previous use as bioindicators in aquatic ecosystems and due to the fact they are one of the most frequent aquatic plant species of the Danube River ecosystems within the Iron Gates Natural Park. Highest amounts are recorded for Ceratophyllum demersum (3.52 ?g/g for Cd; 22.71 ?g/g for Cu; 20.06 ?g/g for Pb; 104.23 ?g/g for Zn). Among the Potamogeton species, the highest amounts of heavy metals are recorded in Potamogeton perfoliatus (1.88 ?g/g for Cd; 13.14 ?g/g for Cu; 13.32 ?g/g for Pb; 57.96 ?g/g for Zn). The sequence for the bioconcentration factors (BCFs) calculated in order to describe the accumulation of the four metals is Cd >> Zn > Pb > Cu. Increase of the zinc concentration determines an increase of the cadmium concentration (Spearman rho=0.40, p=0.02). Conclusions Despite the low ambiental levels of heavy metals, the four aquatic plants have the ability to accumulate significant amounts, which make them useful as biological indicators. BCF value for Ceratophyllum demersum indicated this species as a cadmium hyperaccumulator. PMID:24359799

  18. Phytoremediation potential of weeds in heavy metal contaminated soils of the Bassa Industrial Zone of Douala, Cameroon.

    PubMed

    Lum, A Fontem; Ngwa, E S A; Chikoye, D; Suh, C E

    2014-01-01

    Phytoremediation is a promising option for reclaiming soils contaminated with toxic metals, using plants with high potentials for extraction, stabilization and hyperaccumulation. This study was conducted in Cameroon, at the Bassa Industrial Zone of Douala in 2011, to assess the total content of 19 heavy metals and 5 other elements in soils and phytoremediation potential of 12 weeds. Partial extraction was carried out in soil, plant root and shoot samples. Phytoremediation potential was evaluated in terms of the Biological Concentration Factor, Translocation Factor and Biological Accumulation Coefficient. The detectable content of the heavy metals in soils was Cu:70-179, Pb:8-130, Zn:200-971, Ni:74-296, Co:31-90, Mn:1983-4139, V:165-383, Cr:42-1054, Ba:26-239, Sc:21-56, Al:6.11-9.84, Th:7-22, Sr:30-190, La:52-115, Zr:111-341, Y:10-49, Nb:90-172 in mg kg(-1), and Ti:2.73-4.09 and Fe:12-16.24 in wt%. The contamination index revealed that the soils were slightly to heavily contaminated while the geoaccumulation index showed that the soils ranged from unpolluted to highly polluted. The concentration of heavy metals was ranked as Zn > Ni > Cu > V > Mn > Sc > Co > Pb and Cr in the roots and Mn > Zn > Ni > Cu > Sc > Co > V > Pb > Cr > Fe in the shoots. Dissotis rotundifolia and Kyllinga erecta had phytoextraction potentials for Pb and Paspalum orbicularefor Fe. Eleusine indica and K. erecta had phytostabilisation potential for soils contaminated with Cu and Pb, respectively. PMID:24912226

  19. Selenite-induced hormonal and signalling mechanisms during root growth of Arabidopsis thaliana L.

    PubMed

    Lehotai, Nóra; Kolbert, Zsuzsanna; Peto, Andrea; Feigl, Gábor; Ördög, Attila; Kumar, Devanand; Tari, Irma; Erdei, László

    2012-09-01

    Selenium excess can cause toxicity symptoms, e.g. root growth inhibition in non-hyperaccumulator plants such as Arabidopsis. Selenite-induced hormonal and signalling mechanisms in the course of development are poorly understood; therefore this study set out to investigate the possible hormonal and signalling processes using transgenic and mutant Arabidopsis plants. Significant alterations were observed in the root architecture of the selenite-treated plants, due to the loss of cell viability in the root apex. During mild selenite excess, the plants showed symptoms of the morphogenic response: primary root (PR) shortening and increased initiation of laterals, ensuring better nutrient and water uptake and stress acclimation. As well as lower meristem cell activity, the second reason for the Se-induced growth hindrance is the hormonal imbalance, since the in situ expression of the auxin-responsive DR5::GUS, and consequently the auxin levels, significantly decreased, while that of the cytokinin-inducible ARR5::GUS and the ethylene biosynthetic ACS8::GUS increased. It is assumed that auxin and ethylene might positively regulate selenium tolerance, since reduced levels of them resulted in sensitivity. Moreover, high cytokinin levels caused notable selenite tolerance. During early seedling development, nitric oxide (NO) contents decreased but hydrogen peroxide levels increased reflecting the antagonism between the two signal molecules during Se excess. High levels of NO in gsnor1-3, lead to selenite tolerance, while low NO production in nia1nia2 resulted in selenite sensitivity. Consequently, NO derived from the root nitrate reductase activity is responsible for the large-scale selenite tolerance in Arabidopsis. PMID:22988013

  20. Effects of selenite and selenate application on growth and shoot selenium accumulation of pak choi (Brassica chinensis L.) during successive planting conditions.

    PubMed

    Li, Jun; Liang, Dongli; Qin, Siyue; Feng, Puyang; Wu, Xiongping

    2015-07-01

    Selenate and selenite are two main kinds of inorganic selenium (Se) sources in soil, but these substances can pose threats to the environment. Phytoextraction is an emerging technology to remove Se from polluted soils by using a hyper-accumulator. In this study, a pot experiment was conducted to investigate Se phytoextraction potential of pak choi (Brassica chinensis L.) and to determine the effects of Se on growth and Se accumulation of pak choi under successive planting conditions (four crops). Results showed that Se concentration in pak choi shoots significantly increased as selenate and selenite rates increased. Se concentration increased in successive crops on soil treated with selenite; by contrast, Se concentration decreased in crops on soil treated with selenate. Se concentrations of pak choi on soil treated with selenate were higher than those on soil treated with selenite. The maximum Se accumulations amount in crops on selenite- and selenate-treated soil were 7818 and 8828 ?g · pot(-1), respectively. High bioconcentration factor (BCF) values indicated that pak choi could accumulate more Se from Se-contaminated soil. The Se phytoextraction efficiency of pak choi increased under successive planting conditions in selenite and selenate treatments; the maximum Se phytoextraction efficiencies of four successive crops of pak choi on selenite- and selenate-treated soil were 4.91 and 31.90 %, respectively. These differences between selenate and selenite treatments were attributed to the differences in Se forms in soil. Total and available Se contents in soil decreased significantly during repeated planting crops on soil treated with selenate; conversely, total and available Se contents decreased slightly in crops on soil treated with selenite. These results suggested that pak choi could highly tolerate and accumulate Se. Thus, pak choi may remove Se from contaminated soil; indeed, pak choi can be used in the phytoextraction of Se in polluted soil. PMID:25794583

  1. Nickel accumulation in leaves, floral organs and rewards varies by serpentine soil affinity

    PubMed Central

    Meindl, George A.; Bain, Daniel J.; Ashman, Tia-Lynn

    2014-01-01

    Serpentine soils are edaphically stressful environments that host many endemic plant species. In particular, serpentine soils are high in several heavy metals (e.g. nickel, cobalt and chromium) and these high heavy metal concentrations are thought, in part, to lead to varying levels of plant adaptation and soil affinities (i.e. endemic vs. non-endemic plant species). It is unclear, however, whether serpentine endemics vs. non-endemics differ with respect to heavy metal uptake into either vegetative or reproductive organs. Here, we use nickel as a model to determine whether plant heavy metal uptake varies with the level of endemism in several non-hyperaccumulating species. Under controlled greenhouse conditions, we grew seven plant species from the Brassicaceae family that vary in their degrees of affinity to serpentine soil from low (indifferent) to medium (indicator) and high (endemic) in soil that was nickel supplemented or not. We quantified nickel concentrations in leaves, pistils, anthers, pollen and nectar. While nickel concentrations did not vary across organs or affinities when grown in control soils, under conditions of nickel supplementation endemic species had the lowest tissue concentrations of nickel, particularly when considering leaves and pistils, compared with indifferent/indicator species. Species indifferent to serpentines incorporated higher concentrations of nickel into reproductive organs relative to leaves, but this was not the case for indicator species and endemics where nickel concentration was similar in these organs. Our findings suggest that endemic species possess the ability to limit nickel uptake into above-ground tissues, particularly in reproductive organs where it may interfere with survival and reproduction. Indifferent species accumulated significantly more nickel into reproductive organs compared with leaves, which may limit their reproductive potential relative to endemic species when growing on serpentine soils. Additional work determining the fitness consequences of these differences will further our understanding of edaphic endemism. PMID:24984875

  2. Heavy metal-induced glutathione accumulation and its role in heavy metal detoxification in Phanerochaete chrysosporium.

    PubMed

    Xu, Piao; Liu, Liang; Zeng, Guangming; Huang, Danlian; Lai, Cui; Zhao, Meihua; Huang, Chao; Li, Ningjie; Wei, Zhen; Wu, Haipeng; Zhang, Chen; Lai, Mingyong; He, Yibin

    2014-01-01

    Phanerochaete chrysosporium are known to be vital hyperaccumulation species for heavy metal removal with admirable intracellular bioaccumulation capacity. This study analyzes the heavy metal-induced glutathione (GSH) accumulation and the regulation at the intracellular heavy metal level in P. chrysosporium. P. chrysosporium accumulated high levels of GSH, accompanied with high intracellular concentrations of Pb and Cd. Pb bioaccumulation lead to a narrow range of fluctuation in GSH accumulation (0.72-0.84 ?mol), while GSH plummeted under Cd exposure at the maximum value of 0.37 ?mol. Good correlations between time-course GSH depletion and Cd bioaccumulation were determined (R (2) > 0.87), while no significant correlations have been found between GSH variation and Pb bioaccumulation (R (2) < 0.38). Significantly, concentration-dependent molar ratios of Pb/GSH ranging from 0.10 to 0.18 were observed, while molar ratios of Cd/GSH were at the scope of 1.53-3.32, confirming the dominant role of GSH in Cd chelation. The study also demonstrated that P. chrysosporium showed considerable hypertolerance to Pb ions, accompanied with demand-driven stimulation in GSH synthesis and unconspicuous generation of reactive oxygen stress. GSH plummeted dramatically response to Cd exposure, due to the strong affinity of GSH to Cd and the involvement of GSH in Cd detoxification mechanism mainly as Cd chelators. Investigations into GSH metabolism and its role in ameliorating metal toxicity can offer important information on the application of the microorganism for wastewater treatment. PMID:24723291

  3. Citric acid assisted phytoremediation of cadmium by Brassica napus L.

    PubMed

    Ehsan, Sana; Ali, Shafaqat; Noureen, Shamaila; Mahmood, Khalid; Farid, Mujahid; Ishaque, Wajid; Shakoor, Muhammad Bilal; Rizwan, Muhammad

    2014-08-01

    Phytoextraction is an eco-friendly and cost-effective technique for removal of toxins, especially heavy metals and metalloids from contaminated soils by the roots of high biomass producing plant species with subsequent transport to aerial parts. Lower metal bioavailability often limits the phytoextraction. Organic chelators can help to improve this biological technique by increasing metal solubility. The aim of the present study was to investigate the possibility of improving the phytoextraction of Cd by the application of citric acid. For this purpose, plants were grown in hydroponics under controlled conditions. Results indicated that Cd supply significantly decreased the plant growth, biomass, pigments, photosynthetic characteristics and protein contents which were accompanied by a significant increase in Cd concentration, hydrogen peroxide (H?O?), electrolyte leakage, malondialdehyde (MDA) accumulation and decrease in antioxidant capacity. The effects were dose dependent with obvious effects at higher Cd concentration. Application of CA significantly enhanced Cd uptake and its accumulation in plant roots, stems and leaves. Citric acid alleviated Cd toxicity by increasing plant biomass and photosynthetic and growth parameters alone and in combination with Cd and by reducing oxidative stress as observed by reduction in MDA and H?O? production and decreased electrolyte leakage induced by Cd stress. Application of CA also enhanced the antioxidant enzymes activity alone and under Cd stress. Thus, the data indicate that exogenous CA application can increase Cd uptake and minimize Cd stress in plants and may be beneficial in accelerating the phytoextraction of Cd through hyper-accumulating plants such as Brassica napus L. PMID:24840879

  4. The development dynamics of the maize root transcriptome responsive to heavy metal Pb pollution.

    PubMed

    Gao, Jian; Zhang, Yongzhong; Lu, Chaolong; Peng, Hua; Luo, Mao; Li, Gaoke; Shen, Yaou; Ding, Haiping; Zhang, Zhiming; Pan, Guangtang; Lin, Haijian

    2015-03-01

    Lead (Pb), as a heavy metal element, has become the most important metal pollutant of the environment. With allocating a relatively higher proportion of its biomass in roots, maize could be a potential important model to study the phytoremediation of Pb-contaminated soil. Here we analyzed the maize root transcriptome of inbred lines 9782 under heavy metal lead (Pb) pollution, which was identified as a non-hyperaccumulator for Pb in roots. In the present study, more than 98 millions reads were mapped to define gene structure and detect polymorphism, thereby to qualify transcript abundance along roots development under Pb treatment. A total of 17,707, 17,440, 16,998 and 16,586 genes were identified in maize roots at four developmental stages (0, 12 h, 24 h and 48 h) respectively and 2,825, 2,626, 2161 and 2260 stage-specifically expressed genes were also identified respectively. In addition, based on our RNA-Seq data, transcriptomic changes during maize root development responsive to Pb were investigated. A total of 384 differentially expressed genes (DEGs) (log2Ratio ? 1, FDR ? 0.001) were identified, of which, 36 genes with significant alteration in expression were detected in four developmental stages; 12 DEGs were randomly selected and successful validated by qRT-PCR. Additionally, many transcription factor families might act as the important regulators at different developmental stages, such as bZIP, ERF and GARP et al. These results will expand our understanding of the complex molecular and cellular events in maize root development and provide a foundation for future study on root development in maize under heavy metal pollution and other cereal crops. PMID:25645016

  5. Cadmium stress responses in Brassica juncea: hints from proteomics and metabolomics.

    PubMed

    D'Alessandro, Angelo; Taamalli, Manel; Gevi, Federica; Timperio, Anna Maria; Zolla, Lello; Ghnaya, Tahar

    2013-11-01

    Among heavy metal stressors, cadmium (Cd) pollution is one leading threat to the environment. In this view, research efforts have been increasingly put forward to promote the individuation of phytoextractor plants that are capable of accumulating and withstanding the toxic metals, including Cd, in the aerial parts. We hereby adopted the hyperaccumulator B. juncea (Indian mustard) as a model to investigate plant responses to Cd stress at low (25 ?M) and high (100 ?M) doses. Analytical strategies included mass-spectrometry-based determination of Cd and the assessment of its effect on the leaf proteome and metabolome. Results were thus integrated with routine physiological data. Taken together, physiology results highlighted the deregulation of photosynthesis efficiency, ATP synthesis, reduced transpiration, and the impairment of light-independent carbon fixation reactions. These results were supported at the proteomics level by the observed Cd-dependent alteration of photosystem components and the alteration of metabolic enzymes, including ATP synthase subunits, carbonic anhydrase, and enzymes involved in antioxidant responses (especially glutathione and phytochelatin homeostasis) and the Calvin cycle. Metabolomics results confirmed the alterations of energy-generating metabolic pathways, sulfur-compound metabolism (GSH and PCs), and Calvin cycle. Besides, metabolomics results highlighted the up-regulation of phosphoglycolate, a byproduct of the photorespiration metabolism. This was suggestive of the likely increased photorespiration rate as a means to cope with Cd-induced unbalance in stomatal conductance and deregulation of CO2 homeostasis, which would, in turn, promote CO2 depletion and O2 (and thus oxidative stress) accumulation under prolonged photosynthesis in the leaves from plants exposed to high doses of CdCl2. Overall, it emerges that Cd-stressed B. juncea might rely on photorespiration, an adaptation that would prevent the over-reduction of the photosynthetic electron transport chain and photoinhibition. PMID:24074147

  6. Phytoaccumulation of trace elements by wetland plants: 3. Uptake and accumulation of ten trace elements by twelve plant species

    SciTech Connect

    Qian, J.H.; Zayed, A.; Zhu, Y.L.; Yu, M.; Terry, N.

    1999-10-01

    Interest is increasing in using wetland plants in constructed wetlands to remove toxic elements from polluted wastewater. To identify those wetland plants that hyperaccumulate trace elements, 12 plant species were tested for their efficiency to bioconcentrate 10 potentially toxic trace elements including As, b, Cd, Cr, Cu, Pb, Mn, Hg, Ni, and Se. Individual plants were grown under carefully controlled conditions and supplied with 1 mg L{sup {minus}1} of each trace element individually for 10 d. Except B, all elements accumulated to much higher concentrations in roots than in shoots. Highest shoot tissue concentrations (mg kg{sup {minus}1} DW) of the various trace elements were attained by the following species: umbrella plant (Cyperus alternifolius L.) for Mn (198) and Cr (44); water zinnia (Wedelia trilobata Hitchc.) for Cd (148) and Ni (80); smartweed (Polygonum hydropiperoides Michx.) for Cu (95) and Pb (64); water lettuce (Pistia stratiotes L.) for Hg (92), As (34), and Se (39); and mare's tail (hippuris vulgaris L.) for B (1132). Whereas, the following species attained the highest root tissue concentrations (mg kg{sup {minus}1} DW); stripped rush (Baumia rubiginosa) for Mn (1683); parrot's feather (Myriophyllum brasiliense Camb.) for Cd (1426) and Ni (1077); water lettuce for Cu (1038), Hg (1217), and As (177); smartweed for Cr (2980) and Pb (1882); mare's tail for B (1277); and monkey flower (Mimulus guttatus Fisch.) for Se (384). From a phytoremediation perspective, smartweed was probably the best plant species for trace element removal from wastewater due to its faster growth and higher plant density.

  7. Arsenic(V) Removal in Wetland Filters Treating Drinking Water with Different Substrates and Plants

    PubMed Central

    Li, Qingyun; Tang, Xianqiang; Huang, Zhuo; Lin, Li; Scholz, Miklas

    2014-01-01

    Constructed wetlands are an attractive choice for removing arsenic (As) within water resources used for drinking water production. The role of substrate and vegetation in As removal processes is still poorly understood. In this study, gravel, zeolite (microporous aluminosilicate mineral), ceramsite (lightweight expanded clay aggregate) and manganese sand were tested as prospective substrates while aquatic Juncus effuses (Soft Rush or Common Rush) and terrestrial Pteris vittata L. (Chinese Ladder Brake; known as As hyperaccumulator) were tested as potential wetland plants. Indoor batch adsorption experiments combined with outdoor column experiments were conducted to assess the As removal performances and process mechanisms. Batch adsorption results indicated that manganese sand had the maximum As(V) adsorption rate of 4.55 h–1 and an adsorption capacity of 42.37 ?g/g compared to the other three aggregates. The adsorption process followed the pseudo-first-order kinetic model and Freundlich isotherm equations better than other kinetic and isotherm models. Film-diffusion was the rate-limiting step. Mean adsorption energy calculation results indicated that chemical forces, particle diffusion and physical processes dominated As adsorption to manganese sand, zeolite and gravel, respectively. During the whole running period, manganese sand-packed wetland filters were associated with constantly 90% higher As(V) reduction of approximate 500 ?g/L influent loads regardless if planted or not. The presence of P. vittata contributed to no more than 13.5% of the total As removal. In contrast, J. effuses was associated with a 24% As removal efficiency. PMID:24771958

  8. Transfer of rare earth elements from natural metalliferous (copper and cobalt rich) soils into plant shoot biomass of metallophytes from Katanga (Democratic Republic of Congo)

    NASA Astrophysics Data System (ADS)

    Pourret, Olivier; Lange, Bastien; Jitaru, Petru; Mahy, Grégory; Faucon, Michel-Pierre

    2014-05-01

    The geochemical behavior of rare earth elements (REE) is generally assessed for the characterization of the geological systems where these elements represent the best proxies of processes involving the occurrence of an interface between different media. REE behavior is investigated according to their concentrations normalized with respect to the upper continental crust. In this study, the geochemical fingerprint of REE in plant shoot biomass of an unique metallicolous flora (i.e., Crepidorhopalon tenuis and Anisopappus chinensis) was investigated. The plants originate from extremely copper and cobalt rich soils, deriving from Cu and Co outcrops in Katanga, Democratic Republic of Congo. Some of the species investigated in this study are able to accumulate high amounts of Cu and Co in shoot hence being considered as Cu and Co hyperaccumulators. Therefore, assessing the behavior of REE may lead to a better understanding of the mechanisms of metal accumulation by this flora. The data obtained in this study indicate that REE uptake by plants is not primarily controlled by their concentration and speciation in the soil as previously shown in the literature (Brioschi et al. 2013). Indeed, the REE patterns in shoots are relatively flat whereas soils patterns are Middle REE enriched. In addition, it is worth noting that Eu enrichments occur in aerial parts of the plants. These positive Eu anomalies suggest that Eu3 + can form stable organic complexes replacing Ca2 + in several biological processes as in xylem fluids associated with the general nutrient flux. Therefore, is is possible that the Eu mobility in these fluids is enhanced by its reductive speciation as Eu2 +. Eventually, the geochemical behavior of REE illustrates that metals accumulation in aerial parts of C. tenuis and A. chinensis is mainly driven by dissolved complexation. Brioschi, L., Steinmann, M., Lucot, E., Pierret, M., Stille, P., Prunier, J., Badot, P., 2013. Transfer of rare earth elements (REE) from natural soil to plant systems: implications for the environmental availability of anthropogenic REE. Plant and Soil, 366, 143-163.

  9. Influence of sulfur and cadmium on antioxidants, phytochelatins and growth in Indian mustard.

    PubMed

    Bashir, Humayra; Ibrahim, Mohamed M; Bagheri, Rita; Ahmad, Javed; Arif, Ibrahim A; Baig, M Affan; Qureshi, M Irfan

    2015-01-01

    Soils in many parts of the world are contaminated with heavy metals, leading to multiple, deleterious effects on plants and threats to world food production efficiency. Cadmium (Cd) is one such metal, being toxic at relatively low concentrations as it is readily absorbed and translocated in plants. Sulfur-rich compounds are critical to the impact of Cd toxicity, enabling plants to increase their cellular defence and/or sequester Cd into vacuoles mediated by phytochelatins (PCs). The influence of sulfur on Cd-induced stress was studied in the hyperaccumulator plant Indian mustard (Brassica juncea) using two sulfur concentrations (+S, 300 µM [Formula: see text] and S-deficient -S, [Formula: see text]) with and without the addition of Cd (100 µM CdCl2) at two different time intervals (7 and 14 days after treatment). Compared with control plants (+S/-Cd), levels of oxidative stress were higher in S-deficient (-S/-Cd) plants, and greatest in S-deficient Cd-treated (-S/+Cd) plants. However, additional S (+S/+Cd) helped plants cope with oxidative stress. Superoxide dismutase emerged as a key player against Cd stress under both -S and +S conditions. The activity of ascorbate peroxidase, glutathione reductase and catalase declined in Cd-treated and S-deficient plants, but was up-regulated in the presence of sulfur. Sulfur deficiency mediated a decrease in ascorbate and glutathione (GSH) content but changes in ascorbate (reduced : oxidized) and GSH (reduced : oxidized) ratios were alleviated by sulfur. Our data clearly indicate that a sulfur pool is needed for synthesis of GSH, non-protein thiols and PCs and is also important for growth. Sulfur-based defence mechanisms and the cellular antioxidant pathway, which are critical for tolerance and growth, collapsed as a result of a decline in the sulfur pool. PMID:25587194

  10. Integrated phytobial remediation for sustainable management of arsenic in soil and water.

    PubMed

    Roy, Madhumita; Giri, Ashok K; Dutta, Sourav; Mukherjee, Pritam

    2015-02-01

    Arsenic (As), cited as the most hazardous substance by the U.S. Agency for Toxic Substance and Disease Registry (ATSDR, 2005), is an ubiquitous metalloid which when ingested for prolonged periods cause extensive health effects leading to ultimate untimely death. Plants and microbes can help mitigate soil and groundwater As problem since they have evolved elaborate detoxification machineries against this toxic metalloid as a result of their coexistence with this since the origin of life on earth. Utilization of the phytoremediation and bioremediation potential of the plants and microbes, respectively, is now regarded as two innovative tools that encompass biology, geology, biotechnology and allied sciences with cutting edge applications for sustainable mitigation of As epidemic. Discovery of As hyperaccumulating plants that uptake and concentrate large amounts of this toxic metalloid in their shoots or roots offered new hope to As phytoremediation, solar power based nature's own green remediation. This review focuses on how phytoremediation and bioremediation can be merged together to form an integrated phytobial remediation which could synergistically achieve the goal of large scale removal of As from soil, sediment and groundwater and overcome the drawbacks of the either processes alone. The review also points to the feasibility of the introduction of transgenic plants and microbes that bring new hope for more efficient treatment of As. The review identifies one critical research gap on the importance of remediation of As contaminated groundwater not only for drinking purpose but also for irrigation purpose and stresses that more research should be conducted on the use of constructed wetland, one of the most suitable areas of application of phytobial remediation. Finally the review has narrowed down on different phytoinvestigation and phytodisposal methods, which constitute the most essential and the most difficult part of pilot scale and field scale applications of phytoremediation programs. PMID:25481297

  11. Capability of selected crop plants for shoot mercury accumulation from polluted soils: phytoremediation perspectives.

    PubMed

    Rodriguez, Luis; Rincón, Jesusa; Asencio, Isaac; Rodríguez-Castellanos, Laura

    2007-01-01

    High-biomass crops can be considered as an alternative to hyperaccumulator plants to phytoremediate soils contaminated by heavy metals. In order to assess their practical capability for the absorption and accumulation of Hg in shoots, barley, white lupine, lentil, and chickpea were tested in pot experiments using several growth substrates. In the first experimental series, plants were grown in a mixture of vermiculite and perlite spiked with 8.35 microg g(-1) d.w. of soluble Hg. The mercury concentration of the plants' aerial tissues ranged from 1.51 to 5.13 microg g(-1) d.w. with lentil and lupine showing the highest values. In a second experiment carried out using a Hg-polluted soil (32.16 microg g(-1) d.w.) collected from a historical mining area (Almadén, Spain), the crop plants tested only reached shoot Hg concentration up to 1.13 microg g(-1) d.w. In the third experimental series, the Almadén soil was spiked with 1 microg g(-1) d.w. of soluble Hg; as a result, mercury concentrations in the plant shoots increased approximately 6 times for lupine, 5 times for chickpea, and 3.5 times for barley and lentil, with respect to those obtained with the original soil without Hg added. This marked difference was attributed to the low availability of Hg in the original Almadin soil and its subsequent increase in the Hg-spiked soil. The low mercury accumulation yields obtained for all plants do not make a successful decontamination of the Almadén soils possible byphytoremediation using crop plants. However, since the crops tested can effectively decrease the plant-available Hg level in this soil, their use could, to some extent, reduce the environmental risk of Hg pollution in the area. PMID:18246711

  12. Phytoremediation of cadmium improved with the high production of endogenous phenolics and free proline contents in Parthenium hysterophorus plant treated exogenously with plant growth regulator and chelating agent.

    PubMed

    Ali, Nasir; Hadi, Fazal

    2015-09-01

    Pot experiments were conducted to evaluate the effects of gibberellic acid (GA3) and ethylenediaminetetraacetic acid (EDTA) on growth parameters, cadmium (Cd) phytoextraction, total phenolics, free proline and chlorophyll content of Parthenium hysterophorus plant grown in Cd-contaminated (100 mg/kg) soil. GA3 was applied as foliar spray (10(-2), 10(-4) and 10(-6) M) while EDTA (40 mg/kg soil) was added to soil as single and in split doses. Results showed decrease in growth parameters due to Cd stress but P. hysterophorus plant demonstrated Cd hyperaccumulator potential based on bioconcentration factor (BCF). Lower concentration of GA3 (10(-6) M) showed highest significant increase in the growth parameters while Cd concentration, accumulation (1.97?±?0.11 mg/DBM) and bioconcentration (9.75?±?0.34) was significantly higher in the treatment T11 (GA3 10(-2)?+?split doses of EDTA). Cadmium significantly increased the root free proline while total phenolic concentration was significantly high in all parts of the plant. Chlorophyll contents were significantly reduced by Cd. GA3 showed significant increase in phenolic and chlorophyll contents in plant. Cadmium accumulation in plant tissues showed positive correlation with free proline (R (2)?=?0.527, R (2)?=?0.630) and total phenolics (R (2)?=?0.554, R (2)?=?0.723) in roots and leaves, respectively. Cd contents negatively correlated with biomass, chlorophyll and total water contents. Proline and phenolic contents showed positive correlation with dry biomass of plant. These findings suggest further investigation to study the role of endogenous phenolics and proline in heavy metal phytoremediation. PMID:25940488

  13. Abcb1 gene expression pattern and function of copper detoxification in Fujian oyster, Crassostrea angulata.

    PubMed

    Shi, Bo; Xiang, Xu; Ke, Yizhou; Zhou, Long; Ke, Caihuan

    2015-12-01

    Oysters are considered hyper-accumulators of Cu, but the molecular mechanism by which they maintain Cu cell homeostasis is still unclear. ATP-binding cassette protein subfamily B member 1 (ABCB1, P-glycoprotein) can transport a variety of substrates across the cell membrane in aquatic animals. In this study, to provide insight into the roles of ABCB1 in resistance against Cu in oysters, complete cDNA of abcb1 gene in Crassostrea angulata was cloned and analyzed. The complete sequence of C. angulata ABCB1 showed high identity to ABCB1 from other bivalves and contained some classical motifs of ABCB transport proteins. Abcb1 was mainly expressed in the apical epithelial cell of gills and epithelia of mantles. Abcb1 expression and Cu accumulation were also studied in control oysters and oysters exposed to Cu (30, 100, 300?g/L Cu, 1-15days). Cu accumulation in the gill and mantle were measured after abcb1 gene interference. The complete sequence of C. angulata ABCB1 showed high identity to ABCB1 from other bivalves and contained some classical motifs of ABCB transport proteins. The mRNA transcript of abcb1 showed hypersensitivity to Cu exposure. A concentration-dependent highest abcb1 mRNA level (up to 5.61-fold to the control) in the gill and mantle existed across all Cu exposure concentrations after 3days of Cu exposure. The gill and mantle Cu concentration were significantly higher after the abcb1 mRNA interference. According to these results, it is here speculated that ABCB1 may underlie cell protection against Cu in C. angulata. PMID:26310361

  14. Proteomic analysis of eucalyptus leaves unveils putative mechanisms involved in the plant response to a real condition of soil contamination by multiple heavy metals in the presence or absence of mycorrhizal/rhizobacterial additives.

    PubMed

    Guarino, Carmine; Conte, Barbara; Spada, Valentina; Arena, Simona; Sciarrillo, Rosaria; Scaloni, Andrea

    2014-10-01

    Here we report on the growth, accumulation performances of, and leaf proteomic changes in Eucalyptus camaldulensis plants harvested for different periods of time in an industrial, heavy metals (HMs)-contaminated site in the presence or absence of soil microorganism (AMs/PGPRs) additives. Data were compared to those of control counterparts grown in a neighboring nonpolluted district. Plants harvested in the contaminated areas grew well and accumulated HMs in their leaves. The addition of AMs/PGPRs to the polluted soil determined plant growth and metal accumulation performances that surpassed those observed in the control. Comparative proteomics suggested molecular mechanisms underlying plant adaptation to the HMs challenge. Similarly to what was observed in laboratory-scale investigations on other metal hyperaccumulators but not on HMs-sensitive plants, eucalyptus grown in the contaminated areas showed an over-representation of enzymes involved in photosynthesis and the Calvin cycle. AMs/PGPRs addition to the soil increased the activation of these energetic pathways, suggesting the existence of signaling mechanisms that address the energy/reductive power requirement associated with augmented growth performances. HMs-exposed plants presented an over-representation of antioxidant enzymes, chaperones, and proteins involved in glutathione metabolism. While some antioxidant enzymes/chaperones returned to almost normal expression values in the presence of AMs/PGPRs or in plants exposed to HMs for prolonged periods, proteins guaranteeing elevated glutathione levels were constantly over-represented. These data suggest that glutathione (and related phytochelatins) could act as key molecules for ensuring the effective formation of HMs-chelating complexes that are possibly responsible for the observed plant tolerance to metal stresses. Overall, these results suggest potential genetic traits for further selection of phytoremediating plants based on dedicated cloning or breeding programs. PMID:25203592

  15. Phytoremediation: using green plants to clean up contaminate soil, groundwater, and wastewater

    SciTech Connect

    Negri, M.C.; Hinchman, R.R.; Gatliff, E.G.

    1996-07-01

    Phytoremediation, an emerging cleanup technology for contaminated soils, groundwater, and wastewater that is both low-tech and low-cost, is defined as the engineered use of green plants (including grasses, forbs, and woody species) to remove, contain, or render harmless such environmental contaminants as heavy metals, trace elements, organic compounds and radioactive compounds in soil or water. Our research includes a successful field demonstration of a plant bioreactor for processing the salty wastewater from petroleum wells; the demonstration is currently under way at a natural gas well site in Oklahoma, in cooperation with Devon Energy Corporation. A greenhouse experiment on zinc uptake in hybrid poplar (Populus sp.) was initiated in 1995. These experiments are being conducted to confirm and extend field data indicating high levels of zinc (4,200 ppm) in leaves of hybrid poplar growing as a cleanup system at a site with zinc contamination in the root zone of some of the trees. Analyses of soil water from experimental pots that had received several doses of zinc indicated that the zinc was totally sequestered by the plants in about 4 hours during a single pass through the root system. The data also showed concentrations of sequestered metal of >38,000 ppm Zn in the dry root tissue. These levels of sequestered zinc exceed the levels found in either roots or tops of many of the known ``hyperaccumulator`` species. Because the roots sequester most of the contaminant taken up in most plants, a major objective of this program is to determine the feasibility of root harvesting as a method to maximize the removal of contaminants from soils. Available techniques and equipment for harvesting plant roots, including young tree roots, are being evaluated and modified as necessary for use with phytoremediation plants.

  16. Nickel phytoremediation potential of the Mediterranean Alyssoides utriculata (L.) Medik.

    PubMed

    Roccotiello, Enrica; Serrano, Helena Cristina; Mariotti, Mauro Giorgio; Branquinho, Cristina

    2015-01-01

    This study investigated the accumulation and distribution of nickel in the leaves and roots of the Mediterranean shrub Alyssoides utriculata to assess its potential use in phytoremediation of Ni contaminated soils. Total (AAS and ICP-MS) Ni, Ca and Mg contents were analyzed in the plants and related to their bioavailability (in EDTA) in serpentine and non-serpentine soils. To find the relationships between the soil available Ni and the Ni content of this species, we also evaluated possible interactions with Ca and Mg. The bioaccumulation factor (BF) and the translocation factor (TF) were determined to assess the tolerance strategies developed by A. utriculata and to evaluate its potential for phytoextraction or phytostabilization. The leaf Ni is higher than 1000 ?g g(-1) which categorizes the species as a Ni-hyperaccumulator and a great candidate for Ni-phytoextraction purposes. In addition to the accumulation of Ni, the leaf Mg is also correlated with soil bioavailable concentrations. The Ca uptake and translocation were significantly lower in serpentine plants (higher Ni), as such, the leaf Ca is probably greatly influenced either by the soil's Ni or the soil Ca/Mg ratio. The BFs and TFs are strongly higher than 1 and generally did not significantly differed between plants from serpentine (higher Ni) and non-serpentine soils (lower Ni). The present study highlights for the first time that A. utriculata could be suitable for cleaning Ni-contaminated areas and provides a contribution to the very small volume of data available on the potential use of native Mediterranean plant species from contaminated sites in phytoremediation technologies. PMID:24630460

  17. [Continuous remediation of heavy metal contaminated soil by co-cropping system enhanced with chelator].

    PubMed

    Wei, Ze-Bin; Guo, Xiao-Fang; Wu, Qi-Tang; Long, Xin-Xian

    2014-11-01

    In order to elucidate the continuous effectiveness of co-cropping system coupling with chelator enhancement in remediating heavy metal contaminated soils and its environmental risk towards underground water, soil lysimeter (0.9 m x 0.9 m x 0.9 m) experiments were conducted using a paddy soil affected by Pb and Zn mining in Lechang district of Guangdong Province, 7 successive crops were conducted for about 2.5 years. The treatments included mono-crop of Sedum alfredii Hance (Zn and Cd hyperaccumulator), mono-crop of corn (Zea mays, cv. Yunshi-5, a low-accumulating cultivar), co-crop of S. alfredii and corn, and co-crop + MC (Mixture of Chelators, comprised of citric acid, monosodium glutamate waste liquid, EDTA and KCI with molar ratio of 10: 1:2:3 at the concentration of 5 mmol x kg(-1) soil). The changes of heavy metal concentrations in plants, soil and underground water were monitored. Results showed that the co-cropping system was suitable only in spring-summer seasons and significantly increased Zn and Cd phytoextraction. In autumn-winter seasons, the growth of S. alfredii and its phytoextraction of Zn and Cd were reduced by co-cropping and MC application. In total, the mono-crops of S. alfredii recorded a highest phytoextraction of Zn and Cd. However, the greatest reduction of soil Zn, Cd and Pb was observed with the co-crop + MC treatment, the reduction rates were 28%, 50%, and 22%, respectively, relative to the initial soil metal content. The reduction of this treatment was mainly attributed to the downwards leaching of metals to the subsoil caused by MC application. The continuous monitoring of leachates during 2. 5 year's experiment also revealed that the addition of MC increased heavy metal concentrations in the leaching water, but they did not significantly exceed the III grade limits of the underground water standard of China. PMID:25639110

  18. Arsenic extraction and speciation in plants: Method comparison and development.

    PubMed

    Zhao, Di; Li, Hong-Bo; Xu, Jia-Yi; Luo, Jun; Ma, Lena Qiying

    2015-08-01

    We compared four methods to extract arsenic (As) from three different plants containing different As levels for As speciation with the goal of developing a more efficient method, i.e., As-hyperaccumulator Pteris vittata at 459-7714mgkg(-1), rice seedling at 53.4-574mgkg(-1), and tobacco leaf at 0.32-0.35mgkg(-1). The four methods included heating with dilute HNO3, and sonication with phosphate buffered solution, methanol/water, and ethanol/water, with As being analyzed using high-performance liquid chromatography coupled with inductively-coupled plasma mass spectrometry (HPLC-ICP-MS). Among the four methods, the ethanol/water method produced the most satisfactory extraction efficiency (~80% for the roots and >85% for the fronds) without changing As species based on P. vittata. The lower extraction efficiency from P. vittata roots was attributed to its dominance by arsenate (82%) while arsenite dominated in the fronds (89%). The ethanol/water method used sample:solution ratio of 1:200 (0.05g:10mL) with 50% ethanol and 2h sonication. Based on different extraction times (0.5-2h), ethanol concentrations (25-100%) and sample:solution ratios (1:50-1:300), the optimized ethanol/water method used less ethanol (25%) and time (0.5h for the fronds and 2h for the roots). Satisfactory extraction was also obtained for tobacco leaf (78-92%) and rice seedlings (~70%) using the optimized method, which was better than the other three methods. Based on satisfactory extraction efficiency with little change in As species during extraction from three plants containing different As levels, the optimized method has the potential to be used for As speciation in other plants. PMID:25863504

  19. The role of plant-associated bacteria in the mobilization and phytoextraction of trace elements in contaminated soils

    PubMed Central

    Sessitsch, Angela; Kuffner, Melanie; Kidd, Petra; Vangronsveld, Jaco; Wenzel, Walter W.; Fallmann, Katharina; Puschenreiter, Markus

    2013-01-01

    Phytoextraction makes use of trace element-accumulating plants that concentrate the pollutants in their tissues. Pollutants can be then removed by harvesting plants. The success of phytoextraction depends on trace element availability to the roots and the ability of the plant to intercept, take up, and accumulate trace elements in shoots. Current phytoextraction practises either employ hyperaccumulators or fast-growing high biomass plants; the phytoextraction process may be enhanced by soil amendments that increase trace element availability in the soil. This review will focus on the role of plant-associated bacteria to enhance trace element availability in the rhizosphere. We report on the kind of bacteria typically found in association with trace element – tolerating or – accumulating plants and discuss how they can contribute to improve trace element uptake by plants and thus the efficiency and rate of phytoextraction. This enhanced trace element uptake can be attributed to a microbial modification of the absorptive properties of the roots such as increasing the root length and surface area and numbers of root hairs, or by increasing the plant availability of trace elements in the rhizosphere and the subsequent translocation to shoots via beneficial effects on plant growth, trace element complexation and alleviation of phytotoxicity. An analysis of data from literature shows that effects of bacterial inoculation on phytoextraction efficiency are currently inconsistent. Some key processes in plant–bacteria interactions and colonization by inoculated strains still need to be unravelled more in detail to allow full-scale application of bacteria assisted phytoremediation of trace element contaminated soils. PMID:23645938

  20. Effect of Inoculation with Glomus versiforme on Cadmium Accumulation, Antioxidant Activities and Phytochelatins of Solanum photeinocarpum

    PubMed Central

    Tan, Shi-Yun; Jiang, Qiu-Yun; Zhuo, Feng; Liu, Hui; Wang, Yu-Tao; Li, Shao-Shan; Ye, Zhi-Hong; Jing, Yuan-Xiao

    2015-01-01

    The plant growth, phosphate acquisition, Cd translocation, phytochelatins (PCs) production and antioxidant parameters [superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POD), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione (GSH), ascorbate (ASA) and malonaldehyde (MDA)] were investigated in Cd-hyperaccumulator Solanum photeinocarpum inoculated with Glomus versiforme BGC GD01C (Gv) in Cd-added soils (0, 5, 10, 20, 40 mg Cd kg-1 soil). Mycorrhizal colonization rates were generally high (from 77% to 94%), and hardly affected by Cd. Gv colonization significantly enhanced P acquisition, growth and total Cd uptakes in both shoots and roots of S. photeinocarpum at all Cd levels. Meanwhile, Gv symbiosis significantly increased Cd concentration in the roots, and decreased Cd concentration in the shoots at all Cd levels, which indicates that Gv could promote phytostabilization by enhancing Cd accumulation in the roots to inhibit its translocation to shoots and the “dilution effects” linked to an increase in plant dry matter yield and a reduced Cd partitioning to shoots. Moreover, the improvement of CAT, POD and APX activities in the leaves of mycorrhizal plants infers that Gv symbiosis helped S. photeinocarpum to relieve oxidative damage to biomolecules in Cd-contaminated soil. The evident decline of MDA content in the leaves of mycorrhizal plants indicates that Gv symbiosis evidently improved antioxidant activities, and the enhancement of PCs production in the leaves of mycorrhizal plants suggests that Gv-inoculated plant may be more efficient to relieve Cd phytotoxicity. Therefore, the possible mechanisms of Cd phytotoxicity alleviation by Gv can be concluded as the decline of Cd concentration in the shoots and the improvement of P acquisition, PCs production and activities of CAT, POD, APX in mycorrhizal plants. PMID:26176959

  1. Influence of sulfur and cadmium on antioxidants, phytochelatins and growth in Indian mustard

    PubMed Central

    Bashir, Humayra; Ibrahim, Mohamed M.; Bagheri, Rita; Ahmad, Javed; Arif, Ibrahim A.; Baig, M. Affan; Qureshi, M. Irfan

    2015-01-01

    Soils in many parts of the world are contaminated with heavy metals, leading to multiple, deleterious effects on plants and threats to world food production efficiency. Cadmium (Cd) is one such metal, being toxic at relatively low concentrations as it is readily absorbed and translocated in plants. Sulfur-rich compounds are critical to the impact of Cd toxicity, enabling plants to increase their cellular defence and/or sequester Cd into vacuoles mediated by phytochelatins (PCs). The influence of sulfur on Cd-induced stress was studied in the hyperaccumulator plant Indian mustard (Brassica juncea) using two sulfur concentrations (+S, 300 µM SO42? and S-deficient ?S, 30?MSO42?) with and without the addition of Cd (100 µM CdCl2) at two different time intervals (7 and 14 days after treatment). Compared with control plants (+S/?Cd), levels of oxidative stress were higher in S-deficient (?S/?Cd) plants, and greatest in S-deficient Cd-treated (?S/+Cd) plants. However, additional S (+S/+Cd) helped plants cope with oxidative stress. Superoxide dismutase emerged as a key player against Cd stress under both ?S and +S conditions. The activity of ascorbate peroxidase, glutathione reductase and catalase declined in Cd-treated and S-deficient plants, but was up-regulated in the presence of sulfur. Sulfur deficiency mediated a decrease in ascorbate and glutathione (GSH) content but changes in ascorbate (reduced : oxidized) and GSH (reduced : oxidized) ratios were alleviated by sulfur. Our data clearly indicate that a sulfur pool is needed for synthesis of GSH, non-protein thiols and PCs and is also important for growth. Sulfur-based defence mechanisms and the cellular antioxidant pathway, which are critical for tolerance and growth, collapsed as a result of a decline in the sulfur pool. PMID:25587194

  2. Optimization of plant mineral nutrition under growth-limiting conditions in a lunar greenhouse

    NASA Astrophysics Data System (ADS)

    Zaets, I.; Voznyuk, T.; Kovalchuk, M.; Rogutskyy, I.; Lukashov, D.; Mytrokhyn, O.; Mashkovska, S.; Foing, B.; Kozyrovska, N.

    It may be assumed that the first plants in a lunar base will play a main role in forming a protosoil of acceptable fertility needed for purposively growing second generation plants like wheat, rice, tulips, etc. The residues of the first-generation plants could be composted and transformed by microorganisms into a soil-like substrate within a loop of regenerative life support system. The lunar regolith may be used as a substrate for plant growth at the very beginning of a mission to reduce its cost. The use of microbial communities for priming plants will allow one to facilitate adaption to stressful conditions and to support the plant development under growth limiting conditions. Well-defined plant-associated bacteria were used for growing three cultivars to colonize French marigold (Tagetes patula L.) in anorthosite, a substrate of low bioavailability, analogous to a lunar rock. The consortium was composed of plant growth promoting rhizobacteria and the bacterium Paenibacillus sp. IMBG156 which stimulated seed germination, better plant development, and finally, the flowering of inoculated tagetes. In contrast, control plants grew poorly in the anorthosite and practically did not survive until flowering. Analysis of bacterial community composition showed that all species colonized plant roots, however, the rate of colonization depended on the allelopatic characteristics of marigold varieties. Bacteria of consortium were able to liberate some elements (Ca, Fe, Mn, Si, Ni, Cu, Zn) from substrate anorthosite. Plant colonization by mixed culture of bacterial strains resulted in the increase of accumulation of K, Mg, Mn by the plant and in the lowering of the level of toxic metal accumulation. It was assumed that a rationally assembled consortium of bacterial strains promoted germination of marygold seeds and supported the plant development under growth limiting conditions by means of bioleaching plant essential nutritional elements and by protecting the plant against hyperaccumulation of some toxic metals.

  3. Citric acid enhances the phytoextraction of chromium, plant growth, and photosynthesis by alleviating the oxidative damages in Brassica napus L.

    PubMed

    Afshan, Sehar; Ali, Shafaqat; Bharwana, Saima Aslam; Rizwan, Muhammad; Farid, Mujahid; Abbas, Farhat; Ibrahim, Muhammad; Mehmood, Muhammad Aamer; Abbasi, Ghulam Hasan

    2015-08-01

    Chromium (Cr) toxicity is widespread in crops grown on Cr-contaminated soils and has become a serious environmental issue which requires affordable strategies for the remediation of such soils. This study was performed to assess the performance of citric acid (CA) through growing Brassica napus in the phytoextraction of Cr from contaminated soil. Different Cr (0, 100, and 500 ?M) and citric acid (0, 2.5, and 5.0 mM) treatments were applied alone and in combinations to 4-week-old seedlings of B. napus plants in soil under wire house condition. Plants were harvested after 12 weeks of sowing, and the data was recorded regarding growth characteristics, biomass, photosynthetic pigments, malondialdehyde (MDA), electrolytic leakage (EL), antioxidant enzymes, and Cr uptake and accumulation. The results showed that the plant growth, biomass, chlorophyll contents, and carotenoid as well as soluble protein concentrations significantly decreased under Cr stress alone while these adverse effects were alleviated by application of CA. Cr concentration in roots, stem, and leaves of CA-supplied plant was significantly reduced while total uptake of Cr increased in all plant parts with CA application. Furthermore, in comparison with Cr treatments alone, CA supply reduced the MDA and EL values in both shoots and roots. Moreover, the activity of superoxide dismutase (SOD), guaiacol peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) in shoots and roots markedly increased by 100 ?M Cr exposure, while decreased at 500 ?M Cr stress. CA application enhanced the activities of antioxidant enzymes compared to the same Cr treatment alone. Thus, the data indicate that exogenous CA application can increase Cr uptake and can minimize Cr stress in plants and may be beneficial in accelerating the phytoextraction of Cr through hyper-accumulating plants such as B. napus. PMID:25850739

  4. Model optimization of cadmium and accumulation in switchgrass (Panicum virgatum L.): potential use for ecological phytoremediation in Cd-contaminated soils.

    PubMed

    Wang, Quanzhen; Gu, Muyu; Ma, Xiaomin; Zhang, Hongjuan; Wang, Yafang; Cui, Jian; Gao, Wei; Gui, Jing

    2015-11-01

    Soil pollution with heavy metals is an increasingly serious threat to the environment, food security, and human health. Therefore, it is urgent to develop economic and highly efficient soil restoration technology for environmental improvement; phytoremediation is an option that is safe, has low cost, and is environmentally friendly. However, in selecting hyperaccumulators or tolerant plants, theories and operation technologies for optimal restoration should be satisfied. In this study, the switchgrass growth response and performance of phytoextraction under the coupling effect of Cd and pH were investigated by evaluating seed germination, seedling growth, and the Cd content in the plant to evaluate the potential use of switchgrass as a phytoremediation plant in cadmium contaminated soil. This study conducted three sets of independent experiments with five levels of Cd concentrations, including two orthogonal matrix designs of combining Cd with pH values. The results showed that switchgrass was germinated well under all treatments (Cd concentration of 0-500 ?M), but the seedling growth was significantly affected by Cd and pH, as shown by multivariate regression analyses. Hormesis was found during the growth of switchgrass plants exposed to low Cd concentrations under hydroponic conditions, and switchgrass plants were capable of developing with a Cd concentration of 100-175 ?M and pH of 4.1-5.9. Mild acidic conditions can enhance the ability of Cd to accumulate in switchgrass. Switchgrass was moderately tolerant to Cd and may be used as a phytoremediation plant for Cd-contaminated soils in the future. Our results also suggest that hormetic effects should be taken into consideration in the phytoremediation of Cd-contaminated soils. We discuss the physiological and biochemical mechanisms contributing to the effective application of the plant for the phytoremediation of Cd-contaminated soils. PMID:26092360

  5. The pheromone-induced nuclear accumulation of the Fus3 MAPK in yeast depends on its phosphorylation state and on Dig1 and Dig2

    PubMed Central

    Blackwell, Ernest; Kim, Hye-Jin N; Stone, David E

    2007-01-01

    Background Like mammalian MAP kinases, the mating-specific Fus3 MAPK of yeast accumulates in the nuclei of stimulated cells. Because Fus3 does not appear to be subjected to active nucleo-cytoplasmic transport, it is not clear how its activation by mating pheromone effects the observed change in its localization. One possibility is that the activation of Fus3 changes its affinity for nuclear and cytoplasmic tethers. Results Dig1, Dig2, and Ste12 are nuclear proteins that interact with Fus3. We found that the pheromone-induced nuclear accumulation of a Fus3-GFP reporter is reduced in cells lacking Dig1 or Dig2, whereas Fus3T180AY182A-GFP localization was unaffected by the absence of these proteins. This suggests that Dig1 and Dig2 contribute to the retention of phosphorylated Fus3 in the nucleus. Moreover, overexpression of Ste12 caused the hyper-accumulation of Fus3-GFP (but not Fus3T180AY182A-GFP) in the nuclei of pheromone-treated cells, suggesting that Ste12 also plays a role in the nuclear retention of phosphorylated Fus3, either by directly interacting with it or by transcribing genes whose protein products are Fus3 tethers. We have previously reported that overexpression of the Msg5 phosphatase inhibits the nuclear localization of Fus3. Here we show that this effect depends on the phosphatase activity of Msg5, and provide evidence that both nuclear and cytoplasmic Msg5 can affect the localization of Fus3. Conclusion Our data are consistent with a model in which the pheromone-induced phosphorylation of Fus3 increases its affinity for nuclear tethers, which contributes to its nuclear accumulation and is antagonized by Msg5. PMID:17963515

  6. Bacterial ability in AsIII oxidation and AsV reduction: Relation to arsenic tolerance, P uptake, and siderophore production.

    PubMed

    Ghosh, Piyasa; Rathinasabapathi, Bala; Teplitski, Max; Ma, Lena Q

    2015-11-01

    The relationship between bacterial ability in arsenic transformation, siderophore production, and P uptake was investigated using six arsenic-resistant bacteria isolated from the rhizosphere of arsenic-hyperaccumulator Pteris vittata. Bacterial strains of PG5 and 12 were better arsenite (AsIII) oxidizers (31-46 vs. 6.2-21% of 1 mM AsIII) whereas PG 6, 9, 10 and 16 were better arsenate (AsV) reducers (58-95 vs. 7.5-46% of 1 mM AsV). Increase in AsV concentration from 0 to 1 mM induced 3.0-8.4 times more P uptake by bacteria but increase in P concentration from 0.1 to 1 mM reduced AsV uptake by 17-71%, indicating that P and AsV were taken up by P transporters. Bacteria producing more siderophores (PG5 and 12; >73 ?M equiv) showed greater AsIII oxidation and AsIII resistance than those producing less siderophore (PG 6, 9, 10 and 16; <23 ?M equiv). This observation was further supported by results obtained from mutants of Pseudomonas fluorescens impaired in siderophore production, as they were 23-25% less tolerant to AsIII than the wild-type. Arsenic-resistant bacteria increased their arsenic tolerance by retaining less arsenic in cells via efficient AsIII oxidation and AsV reduction, which were impacted by P uptake and siderophore production. PMID:25576133

  7. Phytofiltration of arsenic-contaminated groundwater using Pteris vittata L.: effect of plant density and nitrogen and phosphorus levels.

    PubMed

    Natarajan, Seenivasan; Stamps, Robert H; Saha, Uttam K; Ma, Lena Q

    2008-01-01

    This field-scale hydroponic experiment investigated the effects of plant density and nutrient levels on arsenic (As) removal by the As-hyperaccumulator Pteris vittata L. (Chinese brake fern). All ferns were grown in plastic tanks containing 30 L of As-contaminated groundwater (130 microg x L(-1) As) collected from South Florida. The treatments consisted of four plant densities (zero, one, two, or four plants per 30 L), two nitrogen (N) concentrations (50% or 100% of 0.25-strength Hoagland solution [HS]), and two phosphorous (P) concentrations (15% and 30% of 0.25 strength HS). While low P was more effective than high P for plant As removal initially, N levels showed little effect. At 15% P, it took 3 wk for the ferns at a plant density of four to reduce As to less than 10 microg L(-1) (USEPA and WHO standard), whereas it took 4-6 wk at plant densities of one or two. For reused ferns, established plants with more extensive roots than "first-time" ferns, a low plant density of one plant/30 L was more effective, reducing As in water to less than 10 microg L(-1) in 8 h. This translates to an As removal rate of 400 microg h(-l) plant(-1), which is the highest rate reported to date. Arsenic-concentration in tanks with no plants as a control remained high throughout the experiment. Using more established ferns supplemented with dilute nutrients (0.25 HS with 25% N and 15% P) with optimized plant density (one plant per 30 L) reduced interplant competition and secondary contamination from nutrients, and can be recommended for phytofiltration of As-contaminated groundwater. This study demonstrated that P. vittata is effective in remediating As-contaminated groundwater to meet recommended standards. PMID:18710097

  8. Biophysical Characterization of the Iron in Mitochondria from Atm1p-depleted Saccharomyces cerevisiae

    PubMed Central

    Miao, Ren; Kim, Hansoo; Koppolu, Uma Mahendra Kumar; Ellis, E. Ann; Scott, Robert A.; Lindahl, Paul A.

    2009-01-01

    Atm1p is an ABC transporter localized in the mitochondrial inner membrane; it functions to export an unknown species into the cytosol and is involved in cellular iron metabolism. Depletion or deletion of Atm1p causes Fe accumulation in mitochondria and a defect in cytosolic Fe/S cluster assembly, but reportedly not a defect in mitochondrial Fe/S cluster assembly. In this study the nature of the accumulated Fe was examined using Mössbauer spectroscopy, EPR, electronic absorption spectroscopy, X-ray absorption spectroscopy, and electron microscopy. The Fe that accumulated in aerobically grown cells was in the form of Fe(III) phosphate nanoparticles similar to that which accumulates in yeast frataxin Yfh1p-deleted or yeast ferredoxin Yah1p-depleted cells. Relative to WT mitochondria, Fe/S cluster and heme levels in Atm1p-depleted mitochondria from aerobic cells were significantly diminished. Atm1p-depletion also caused a build-up of nonheme Fe(II) ions in the mitochondria and an increase in oxidative damage. Atm1p-depleted mitochondria isolated from anaerobically grown cells exhibited WT levels of Fe/S clusters and hemes, and they did not hyper-accumulate Fe. Atm1p-depleted cells lacked Leu1p activity, regardless of whether they were grown aerobically or anaerobically. These results indicate that Atm1p does not participate in mitochondrial Fe/S cluster assembly, and that the species exported by Atm1p is required for cytosolic Fe/S cluster assembly. The Fe/S cluster defect and the Fe-accumulation phenotype, resulting from the depletion of Atm1p in aerobic cells (but not in anaerobic cells), may be secondary effects that are observed only when cells are exposed to oxygen during growth. Reactive oxygen species generated under these conditions might degrade iron-sulfur clusters and lower heme levels in the organelle. PMID:19761223

  9. Vps1 in the late endosome-to-vacuole traffic.

    PubMed

    Hayden, Jacob; Williams, Michelle; Granich, Ann; Ahn, Hyoeun; Tenay, Brandon; Lukehart, Joshua; Highfill, Chad; Dobard, Sarah; Kim, Kyoungtae

    2013-03-01

    Vacuolar protein sorting 1 (Vps1), the yeast homolog to human dynamin, is a GTP hydrolyzing protein, which plays an important role in protein sorting and targeting between the Golgi and late endosomal compartments. In this study, we assessed the functional significance of Vps1 in the membrane traffic towards the vacuole. We show here that vps1 delta cells accumulated FM4-64 to a greater extent than wild-type (WT))cells, suggesting slower endocytic degradation traffic toward the vacuole. In addition, we observed that two endosome-to-vacuole traffic markers, DsRed-FYVE and Ste2-GFP, were highly accumulated in Vps1-deficient cells, further supporting Vps1's implication in efficient trafficking of endocytosed materials to the vacuole. Noteworthy, a simultaneous imaging analysis in conjunction with FM4-64 pulse-chase experiment further revealed that Vps1 plays a role in late endosome to the vacuole transport. Consistently, our subcellular localization analysis showed that Vps1 is present at the late endosome. The hyperaccumulation of endosomal intermediates in the vps1 mutant cells appears to be caused by the disruption of integrity of HOPS tethering complexes, manifested by mislocalization of Vps39 to the cytoplasm. Finally, we postulate that Vps1 functions together with the Endosomal Sorting Complex Required for Transport (ESCRT) complex at the late endosomal compartments, based on the observation that the double mutants, in which VPS1 along with singular ESCRT I, II and III genes have been disrupted, exhibited synthetic lethality. Together, we propose that Vps1 is required for correct and efficient trafficking from the late endosomal compartments to the vacuole. PMID:23385815

  10. Arsenic accumulation by edible aquatic macrophytes.

    PubMed

    Falinski, K A; Yost, R S; Sampaga, E; Peard, J

    2014-01-01

    Edible aquatic macrophytes grown in arsenic (As)-contaminated soil and sediment were investigated to determine the extent of As accumulation and potential risk to humans when consumed. Nasturtium officinale (watercress) and Diplazium esculentum (warabi) are two aquatic macrophytes grown and consumed in Hawaii. Neither has been assessed for potential to accumulate As when grown in As-contaminated soil. Some former sugarcane plantation soils in eastern Hawaii have been shown to have concentrations of total As over 500 mg kg(-1). It was hypothesized that both species will accumulate more As in contaminated soils than in non-contaminated soils. N. officinale and D. esculentum were collected in areas with and without As-contaminated soil and sediment. High soil As concentrations averaged 356 mg kg(-1), while low soil As concentrations were 0.75 mg kg(-1). Average N. officinale and D. esculentum total As concentrations were 0.572 mg kg(-1) and 0.075 mg kg(-1), respectively, corresponding to hazard indices of 0.12 and 0.03 for adults. Unlike previous studies where watercress was grown in As-contaminated water, N. officinale did not show properties of a hyperaccumulator, yet plant concentrations in high As areas were more than double those in low As areas. There was a slight correlation between high total As in sediment and soil and total As concentrations in watercress leaves and stems, resulting in a plant uptake factor of 0.010, an order of magnitude higher than previous studies. D. esculentum did not show signs of accumulating As in the edible fiddleheads. Hawaii is unique in having volcanic ash soils with extremely high sorption characteristics of As and P that limit release into groundwater. This study presents a case where soils and sediments were significantly enriched in total As concentration, but the water As concentration was below detection limits. PMID:24210365

  11. Arsenic(V) Removal in Wetland Filters Treating Drinking Water with Different Substrates and Plants.

    PubMed

    Wu, Min; Li, Qingyun; Tang, Xianqiang; Huang, Zhuo; Lin, Li; Scholz, Miklas

    2014-05-01

    Constructed wetlands are an attractive choice for removing arsenic (As) within water resources used for drinking water production. The role of substrate and vegetation in As removal processes is still poorly understood. In this study, gravel, zeolite (microporous aluminosilicate mineral), ceramsite (lightweight expanded clay aggregate) and manganese sand were tested as prospective substrates while aquatic Juncus effuses (Soft Rush or Common Rush) and terrestrial Pteris vittata L. (Chinese Ladder Brake; known as As hyperaccumulator) were tested as potential wetland plants. Indoor batch adsorption experiments combined with outdoor column experiments were conducted to assess the As removal performances and process mechanisms. Batch adsorption results indicated that manganese sand had the maximum As(V) adsorption rate of 4.55 h(-1) and an adsorption capacity of 42.37 ?g/g compared to the other three aggregates. The adsorption process followed the pseudo-first-order kinetic model and Freundlich isotherm equations better than other kinetic and isotherm models. Film-diffusion was the rate-limiting step. Mean adsorption energy calculation results indicated that chemical forces, particle diffusion and physical processes dominated As adsorption to manganese sand, zeolite and gravel, respectively. During the whole running period, manganese sand-packed wetland filters were associated with constantly 90% higher As(V) reduction of approximate 500 ?g/L influent loads regardless if planted or not. The presence of P. vittata contributed to no more than 13.5% of the total As removal. In contrast, J. effuses was associated with a 24% As removal efficiency. PMID:24771958

  12. Ecological engineering alternatives for remediation and restoration of a drastically disturbed landscape

    SciTech Connect

    Nairn, R.W.; Hare, L.; Mercer, M.; Dresback, K.; Pepple, K.; Kirchner, A.; Cseak, D.; Lossing, J.; Durham, C.; Chen, B.

    1999-07-01

    As part of a Fall 1998 Environmental Science graduate seminar in Ecological Engineering at the University of Oklahoma, students were asked to submit a proposal for the holistic and sustainable restoration of the Tar Creek Superfund Site, Ottawa county, Oklahoma. the Tar Creek site is a portion of an abandoned lead and zinc mining area known as the Tri-State Mining District (OL, KS and MO) and includes approximately 104 square kilometers of disturbed land surface and contaminated water resources in extreme northeastern Oklahoma. Approximately 94 million cubic meters of contaminated water currently exist in the underground voids. In 1979, acidic, metal-rich waters began to discharge into Tar Creek from natural springs, bore holes and mine shafts. In addition, approximately 37 million cubic meters of processed mine waste materials (chat) litter their surface in large piles. Approximately 324 hectares of contaminated tailings settling ponds also exist on site. Student submitted proposals addressed the following four subject areas: passive treatment options for stream water quality improvement, surface reclamation and revegetation, stream habitat restoration and joint ecological and economic sustainability. Proposed designs for passive treatment of the contaminated mine drainage included unique constructed wetland designs that relief on a combination of biological and geochemical processes, use of microbial mats for luxury metal uptake, enhanced iron oxidation via windmill-based aeration and fly ash injection. proposed surface reclamation methods included minimal regrading following by biosolid, ash and other organic amendment applications and several phytoremediation techniques, especially the use of hyperaccumulators. The stream and riparian restoration portion of the proposals focused on chat removal, phytoremediation and species reintroduction. proposed joint ecological and economic sustainability ventures included development of recreational facilities, mining-based tourism and an Ecotechnology Research Park.

  13. Genotypic Variation in the Phytoremediation Potential of Indian Mustard for Chromium

    NASA Astrophysics Data System (ADS)

    Diwan, Hema; Ahmad, Altaf; Iqbal, Muhammad

    2008-05-01

    The term “phytoremediation” is used to describe the cleanup of heavy metals from contaminated sites by plants. This study demonstrates phytoremediation potential of Indian mustard ( Brasicca juncea (L.) Czern. & Coss.) genotypes for chromium (Cr). Seedlings of 10 genotypes were grown hydroponically in artificially contaminated water over a range of environmentally relevant concentrations of Cr (VI), and the responses of genotypes in the presence of Cr, with reference to Cr accumulation, its phytotoxity and anti-oxidative system were investigated. The Cr accumulation potential varied largely among Indian mustard genotypes. At 100 ?M Cr treatment, Pusa Jai Kisan accumulated the maximum amount of Cr (1680 ?g Cr g-1 DW) whereas Vardhan accumulated the minimum (107 ?g Cr g-1 DW). As the tolerance of metals is a key plant characteristic required for phytoremediation purpose, effects of various levels of Cr on biomass were evaluated as the gross effect. The extent of oxidative stress caused by Cr stress was measured as rate of lipid peroxidation. The level of thiobarbituric acid reactive substances (TBARS) was enhanced at all Cr treatments when compared to the control. Inductions of enzymatic and nonenzymatic antioxidants were monitored as metal-detoxifying responses. All the genotypes responded to Cr-induced oxidative stress by modulating nonenzymatic antioxidants [glutathione (GSH) and ascorbate (Asc)] and enzymatic antioxidants [superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR)]. The level of induction, however, differed among the genotypes, being at its maximum in Pusa Jai Kisan and its minimum in Vardhan. Pusa Jai Kisan was grown under natural field conditions with various Cr treatments, and Cr-accumulation capacity was studied. The results confirmed that Pusa Jai Kisan is a hyperaccumulator of Cr and hypertolerant to Cr-induced stress, which makes this genotype a viable candidate for use in the development of phytoremediation technology of Cr-contaminated sites.

  14. A greenhouse and field-based study to determine the accumulation of arsenic in common homegrown vegetables grown in mining-affected soils

    PubMed Central

    Ramirez-Andreotta, Monica D.; Brusseau, Mark L.; Artiola, Janick F.; Maier, Raina M.

    2012-01-01

    The uptake of arsenic by plants from contaminated soils presents a health hazard that may affect home gardeners neighboring contaminated environments. A controlled greenhouse study was conducted in parallel with a co-created citizen science program (home garden experiment) to characterize the uptake of arsenic by common homegrown vegetables near the Iron King Mine and Humboldt Smelter Superfund site in southern Arizona. The greenhouse and home garden arsenic soil concentrations varied considerably, ranging from 2.35 to 533 mg kg?1. In the greenhouse experiment four vegetables were grown in three different soil treatments and in the home garden experiment a total of 63 home garden produce samples were obtained from 19 properties neighboring the site. All vegetables accumulated arsenic in both the greenhouse and home garden experiments, ranging from 0.01 to 23.0 mg kg?1 dry weight. Bioconcentration factors were determined and show that arsenic uptake decreased in the order: Asteraceae > Brassicaceae > Amaranthaceae > Cucurbitaceae > Liliaceae > Solanaceae > Fabaceae. Certain members of the Asteraceae and Brassicaceae plant families have been previously identified as hyperaccumulator plants, and it can be inferred that members of these families have genetic and physiological capacity to accumulate, translocate, and resist high amounts of metals. Additionally, a significant linear correlation was observed between the amount of arsenic that accumulated in the edible portion of the plant and the arsenic soil concentration for the Asteraceae, Brassicaceae, Amaranthaceae, and Fabaceae families. The results suggest that home gardeners neighboring mining operations or mine tailings with elevated arsenic levels should be made aware that arsenic can accumulate considerably in certain vegetables, and in particular, it is recommended that gardeners limit consumption of vegetables from the Asteraceae and Brassicaceae plant families. PMID:23201696

  15. ZmGOLS2, a target of transcription factor ZmDREB2A, offers similar protection against abiotic stress as ZmDREB2A.

    PubMed

    Gu, Lei; Zhang, Yumin; Zhang, Mingshuai; Li, Tao; Dirk, Lynnette M A; Downie, Bruce; Zhao, Tianyong

    2016-01-01

    GALACTINOL SYNTHASE is the first committed enzyme in the raffinose biosynthetic pathway. We have previously characterized the maize (Zea mays) GALACTINOL SYNTHASE2 gene (ZmGOLS2) as abiotic stress induced. To further investigate the regulation of ZmGOLS2 gene expression, individual luciferase expression vectors,in which the luciferase gene was controlled by different lengths of the ZmGOLS2 promoter, were co-transfected into maize protoplasts with either a ZmDREB2A- or a GFP-expression vector. Over-expression of ZmDREB2A up-regulated both the expression of the luciferase gene controlled by the ZmGOLS2 promoter and the endogenous ZmGOLS2 gene in protoplasts. Only one of the two DRE elements in the ZmGOLS2 promoter was identified as necessary for this up-regulation. Expression vectors of GFP, ZmGOLS2 or ZmDREB2A were stably transformed into Arabidopsis. Expression of ZmDREB2A up-regulated the AtGOLS3 gene but only over-expression of ZmGOLS2 resulted in hyper-accumulation of galactinol and raffinose. Regardless, under drought-, heat shock-, high osmotic- or salinity-stress conditions, both the ZmGOLS2- and the ZmDREB2A- expressing plants had greater germination percentages, greater percentages of seedlings becoming autotropic, and/or greater survival percentages during/after stress than the control plants. Under normal growing conditions, transgenic Arabidopsis plants expressing the ZmGOLS2 gene had similar growth to that of untransformed wild type or GFP-expressing control plants, whereas ZmDREB2A over-expressing plants exhibited retarded growth relative to either of the controls. These data suggest that over-expression of ZmGOLS2, rather than the transcription factor ZmDREB2A, is a more practical target for generation of abiotic-stress tolerant crops. PMID:26584560

  16. Nickel-Resistant Bacteria from Anthropogenically Nickel-Polluted and Naturally Nickel-Percolated Ecosystems

    PubMed Central

    Stoppel, R.; Schlegel, H. G.

    1995-01-01

    DNA fragments harboring the nickel resistance determinants from bacteria isolated from anthropogenically polluted ecosystems in Europe and Zaire were compared with those harboring the nickel resistance determinants from bacteria isolated from naturally nickel-percolated soils from New Caledonia by DNA-DNA hybridization. The biotinylated DNA probes were derived from the previously described Alcaligenes eutrophus CH34, Alcaligenes xylosoxidans 31A, Alcaligenes denitrificans 4a-2, and Klebsiella oxytoca CCUG 15788 and four new nickel resistance-determining fragments cloned from strains isolated from soils under nickel-hyperaccumulating trees. Nine probes were hybridized with endonuclease-cleaved plasmid and total DNA samples from 56 nickel-resistant strains. Some of the New Caledonian strains were tentatively identified as Acinetobacter, Pseudomonas mendocina, Comamonas, Hafnia alvei, Burkholderia, Arthrobacter aurescens, and Arthrobacter ramosus strains. The DNA of most strains showed homologies to one or several of the following nickel resistance determinants: the cnr and ncc operons of the strains A. eutrophus CH34 and A. xylosoxidans 31A, respectively, the nre operon of strain 31A, and the nickel resistance determinants of K. oxytoca. On the basis of their hybridization reactions the nickel resistance determinants of the strains could be assigned to four groups: (i) cnr/ncc type, (ii) cnr/ncc/nre type, (iii) K. oxytoca type, and (iv) others. The majority of the strains were assigned to the known groups. Among the strains from Belgium and Zaire, exclusively the cnr/ncc and the cnr/ncc/nre types were found. Among the New Caledonian strains all four types were represented. Homologies to the nre operon were found only in combination with the cnr/ncc operon. The homologies to the cnr/ncc operon were the most abundant and were detected alone or together with homologies to the nre operon. Only the DNA of the strains isolated from soil in Scotland and the United States and that of five of the New Caledonian strains did not show any detectable homologies to any of our probes. The nickel resistance fragment isolated from Burkholderia strain 32W-2 was studied in some detail. This 15-kb BamHI fragment conferred resistance to 1 to 5 mM NiCl(inf2) to Escherichia coli and resistance to up to 25 mM NiCl(inf2) to A. eutrophus. It showed strong homologies to both the cnr/ncc operon and the nre operon and conferred strictly regulated (inducible) nickel resistance to A. eutrophus. PMID:16535048

  17. The evaluation of heavy metal accumulation and application of a comprehensive bio-concentration index for woody species on contaminated sites in Hunan, China.

    PubMed

    Zhao, Xiulian; Liu, Jianfeng; Xia, Xinli; Chu, Jianmin; Wei, Yuan; Shi, Shengqing; Chang, Ermei; Yin, Weilun; Jiang, Zeping

    2014-04-01

    Fast-growing metal-accumulating woody plants are considered potential candidates for phytoextraction of metals. Shuikoushan mining, one of the biggest Pb and Zn production bases in China, presents an important source of the pollution of environment during the last 100 years. Over 150 km(2) of fertile soil have been contaminated by the dust, slag, and tailings from this mining. The goal of the present work has been to determine the content of Pb, Zn, Cd, and Cu in wild woody plants (18 species) naturally growing in this area. Two hundred five plant and soil samples from 11 contaminated sites were collected and analyzed. In addition, to assess the ability of multi-metal accumulation of these trees, we proposed a predictive comprehensive bio-concentration index (CBCI) based on fuzzy synthetic assessment. Our data suggest some adult trees could also accumulate a large amount of metals. Pb concentrations in leaves of Paulownia fortunei (Seem.) Hemsl. (1,179 mg/kg) exceeded the hyperaccumulation threshold (1,000 mg/kg). Elevated Pb concentrations (973.38 mg/kg) were also found in the leaves of Broussonetia papyrifera (L.) Vent., with a Pb bio-concentration factor of up to 0.701. Endemic species, Zenia insignis Chun exhibited huge potential for Zn and Cd phytoextraction, with the highest concentrations of Zn (1,968 mg/kg) and Cd (44.40 mg/kg), characteristic root nodules, and fast growth rates in poor soils. As for multi-metal accumulation ability, native species B. papyrifera was calculated to have the most exceptional ability to accumulate various metals simultaneously (CBCI 2.93), followed by Amorpha fruticosa L. (CBCI 2.72) and Lagerstroemia indica L. (CBCI 2.53). A trend of increasing metal from trunks to leaves (trunks?

  18. The Effects of Soil Type and Chemical Treatment on Nickel Speciation in Refinery Enriched Soils: A Multi-Technique Investigation

    SciTech Connect

    McNear, Jr.,D.; Chaney, R.; Sparks, D.

    2007-01-01

    Aerial deposition of Ni from a refinery in Port Colborne, Ontario, Canada has resulted in the enrichment of 29 km{sup 2} of land with Ni concentrations exceeding the Canadian Ministry of the Environment's remedial action level of 200 mg kg{sup -1}. Several studies on these soils have shown that making the soils calcareous was effective at reducing chemically extractable Ni, as well as alleviating Ni phytotoxicity symptoms in vegetable crops grown in the vicinity of the refinery. Conversely, dolomitic limestone additions resulted in increased uptake of Ni in the Ni hyperaccumulator Alyssum murale 'Kotodesh', a plant whose use was proposed as a remediation strategy for this area. In this paper we use multiple techniques to directly assess the role soil type and lime treatments play in altering the speciation of Ni in the Welland loam and Quarry muck soils around the refinery and relate these findings to Ni mobility and bioavailability. Stirred-flow dissolution experiments using pH 4 HNO{sub 3} showed that Ni release from the limed Quarry muck and Welland loam soils was reduced ({approx}0.10%) relative to the unlimed soils ({approx}2.0%). Electron microprobe analysis (EMPA) identified approximately spherical NiO and Ni metal particles, which are associated with no other metals, and range from 5 to 50 {mu}m in diameter. Synchrotron micro-X-ray absorption fine structure and X-ray fluorescence spectroscopies showed that Ni and Al layered double hydroxide (Ni-Al LDH) phases were present in both the limed and unlimed mineral soils, with a tendency towards more stable (e.g., aged-LDH and phyllosilicate) Ni species in the limed soil, possibly aided by the solubilization of Si with increasing pH. In the muck soils, Ni-organic complexes (namely fulvic acid) dominated the speciation in both limed and unlimed soils. The results reported herein show that both soil type and treatment have a pronounced effect on the speciation of Ni in the soils surrounding the Port Colborne refinery. We provide the first evidence that Ni-Al LDH phases can form in anthropogenically enriched mineral field soils at circumneutral pH, and can lead to a reduction in Ni mobility. In the organic soils Ni is strongly complexed by soil organic matter; a property enhanced with liming. Interestingly, increased accumulation of Ni by A. murale grown in the limed muck and loam soils indicates that the plant may be capable of removing Ni from those fractions typically considered unavailable to most plants.

  19. Developing Seeds of Arabidopsis Store Different Minerals in Two Types of Vacuoles and in the Endoplasmic Reticulum

    PubMed Central

    Otegui, Marisa S.; Capp, Roberta; Staehelin, L. Andrew

    2002-01-01

    Mineral-accumulating compartments in developing seeds of Arabidopsis were studied using high-pressure-frozen/freeze-substituted samples. Developing seeds store minerals in three locations: in the protein storage vacuoles of the embryo, and transiently in the endoplasmic reticulum (ER) and vacuolar compartments of the chalazal endosperm. Energy dispersive x-ray spectroscopy and enzyme treatments suggest that the minerals are stored as phytic acid (myo-inositol-1,2,3,4,5,6-hexakisphosphate) salts in all three compartments, although they differ in cation composition. Whereas embryo globoids contain Mg, K, and Ca as cations, the chalazal ER deposits show high levels of Mn, and the chalazal vacuolar deposits show high levels of Zn. The appearance of the first Zn-phytate crystals coincides with the formation of network-like extensions of the chalazal vacuoles. The core of these networks consists of a branched network of tubular ER membranes, which are separated from the delineating tonoplast membranes by a layer of cytosolic material. Degradation of the networks starts with the loss of the cytosol and is followed by the retraction of the ER, generating a network of collapsed tonoplast membranes that are resorbed. Studies of fertilized fis2 seeds, which hyperaccumulate Zn-phytate crystals in the chalazal vacuolar compartments, suggest that only the intact network is active in mineral sequestration. Mineral determination analysis and structural observations showed that Zn and Mn are mobilized from the endosperm to the embryo at different developmental stages. Thus, Zn appears to be removed from the endosperm at the late globular stage, and Mn stores appear to be removed at the late bent-cotyledon stage of embryo development. The disappearance of the Mn-phytate from the endosperm coincides with the accumulation of two major Mn binding proteins in the embryo, the 33-kD protein from the oxygen-evolving complex of photosystem II and the Mn superoxide dismutase. The possible functions of transient heavy metal storage in the chalazal endosperm are discussed. A model showing how phytic acid, a potentially cytotoxic molecule, is transported from its site of synthesis, the ER, to the different mineral storage sites is presented. PMID:12084829

  20. Mapping of fluoride endemic area and assessment of F(-1) accumulation in soil and vegetation.

    PubMed

    Saini, Poonam; Khan, Suphiya; Baunthiyal, Mamta; Sharma, Vinay

    2013-02-01

    The prevalence of fluorosis is mainly due to the consumption of more fluoride (F(-1)) through drinking water, vegetables, and crops. The objective of the study was mapping of F(-1) endemic area of Newai Tehsil, Tonk district, Rajasthan, India. For the present study, water, soil (0-45 cm), and vegetation samples were collected from 17 villages. Fluoride concentration in water samples ranged from 0.3 to 9.8 mg/l. Out of 17 villages studied, the amounts of F(-1) content of eight villages were found to exceed the permissible limits. Labile F(-1) content and total F(-1) content in soil samples ranges 11.00-70.05 mg/l and 50.3-179.63 ?g g(-1), respectively. F(-1) content in tree species was found in this order Azadirachta indica 47.32-55.76 ?g g(-1) > Prosopis juliflora 40.16-49.63 ?g g(-1) > Acacia tortilis 34.39-43.60 ?g g(-1). While in case of leafy vegetables, F(-1) content order was Chenopodium album 54.23-98.42 ?g g(-1) > Spinacea oleracea 30.41-64.09 ?g g(-1) > Mentha arvensis 35.48-51.97 ?g g(-1). The order of F(-1) content in crops was found as 41.04 ?g g(-1) Pennisetum glaucum > 13.61 ?g g(-1) Brassica juncea > 7.98 ?g g(-1) Triticum sativum in Krishi Vigyan Kendra (KVK) farms. Among vegetation, the leafy vegetables have more F(-1) content. From the results, it is suggested that the people of KVK farms should avoid the use of highly F(-1) containing water for irrigation and drinking purpose. It has been recommended to the government authority to take serious steps to supply drinking water with low F(-1) concentration for the fluorosis affected villages. Further, grow more F(-1) hyperaccumulator plants in F(-1) endemic areas to lower the F(-1) content of the soils. PMID:22638723

  1. Dynamics of Zn in an urban wetland soil-plant system: Coupling isotopic and EXAFS approaches

    NASA Astrophysics Data System (ADS)

    Aucour, Anne-Marie; Bedell, Jean-Philippe; Queyron, Marine; Magnin, Valérie; Testemale, Denis; Sarret, Géraldine

    2015-07-01

    Plants play a key role in the stabilization of metals in contaminated environments. Studies have been performed on Zn uptake and storage mechanisms, mainly for Zn hyperaccumulating plants, though less is known about Zn stabilization in the rhizosphere of non-accumulating plants. This study was focused on the dynamics of Zn in a whole soil-litter-plant system and the processes controlling Zn mobilization and stabilization. The site studied was an infiltration basin receiving urban stormwater, in which Phalaris arundinacea (reed canary grass) developed spontaneously. A combination of chemical extractions (CaCl2, DTPA), EXAFS spectroscopy and Zn stable isotope measurements was applied for the water inlet, soil, plant organs and decaying biomass. Zn speciation changed from the water inlet to the soil. In the soil, Zn was present as Zn-layered double hydroxide (Zn-LDH), tetrahedral and octahedral sorbed Zn species. The formation of Zn-LDH participates in Zn stabilization. Tetrahedral Zn species, which were partly DTPA exchangeable, were enriched in heavy isotopes, whereas octahedral Zn (Zn-LDH and sorbed species) were enriched in light isotopes. Based on a linear model between ?66Zn and Zn speciation, ?66Zn for pure tetrahedral and octahedral end-members were estimated at ca. 0.33‰ and 0.04‰, respectively. In the plant, a mixture of octahedral Zn (attributed to aqueous Zn-organic acid complexes present in the symplasm), and tetrahedral Zn (attributed to apoplasmic Zn-cell wall complexes) was observed in all organs. Large enrichment in light isotopes from the soil to the plant ?66Zn (of ca. -0.6‰) was observed. The stem was enriched in light isotopes versus roots and, to a lesser extent, versus leaves. The results suggest that Zn was taken up via a low-affinity transport system and that Zn was sequestrated in the stem symplasm after transit through leaves. Finally, intense Zn exchanges were observed between the decaying biomass and the soil, with the sorption of heavy Zn from the soil to cell wall remains and release of light Zn to the soil. Overall, this study provides a complete overview of Zn cycling in an urban wetland soil-plant system, and describes several changes in Zn speciation with Zn isotopic fractionation processes in a complex system.

  2. Potential of MuS1 Transgenic Tobacco for Phytoremediation of the Urban Soils Contaminated with Cadmium

    NASA Astrophysics Data System (ADS)

    Kim, K. H.; Kim, Y. N.; Kim, S. H.

    2010-05-01

    Urban soils are prone to contamination by trace elements such as Cd, Cu, Pb and Zn. Phytoremediation is one of the attractive remediation methods for soils contaminated with trace elements due to its non-destructive and environmentally-friendly characteristic. Scientists have tried to find hyper-accumulator plants in nature or to develop transgenic plant through genetic engineering. This study was carried out to identify a potential of MuS1 transgenic tobacco for phytoremediation of the urban soils contaminated with Cd. MuS1 is known as a multiple stress related gene with several lines. The previous study using RT-PCR showed that the expression of MuS1 gene in tobacco plant induced tolerance to Cd stress. For this study, MuS1 transgenic tobacco and wild-type tobacco (control) were cultivated in a hydroponic system treated with Cd (0, 50, 100 and 200?M Cd) for 3 weeks. At harvest, both tobacco and nutrient solution were collected and were analyzed for Cd. Effect of Cd treatment on morphological change of the tobacco leaves was also observed by variable-pressure scanning electron microscopy (VP-SEM). The tolerance of MuS1 transgenic tobacco to Cd stress was better than that of wild-type tobacco at all Cd levels. Especially, wild-type tobacco showed chlorosis and withering with 200?M Cd treatment, whereas MuS1 transgenic tobacco gradually recovered from Cd damage. Wild-type tobacco accumulated more Cd (4.65mg per plant) than MuS1 transgenic tobacco (2.37mg per plant) with 200?M Cd treatment. Cd translocation rate from root to leaves was 81.8 % for wild-type tobacco compared to 37.1 % for MuS1 transgenic tobacco. Result of VP-SEM showed that the number of trichome in the leaves for wild-type tobacco increased in comparison with that for untreated samples after 3 weeks, while that for MuS1 transgenic tobacco was not changed by Cd treatment. Results showed that the mechanism of the recovery of the MuS1 tobacco plant was not by high level of Cd uptake and accumulation in the plant but by revealing resistance to Cd through inducing less Cd uptake and/or more Cd immobilization around roots, resulting in less translocation to shoot. In conclusion, this study showed a potential to use MuS1 transgenic tobacco for phytoremediation of the urban soils contaminated with Cd.

  3. Environmental hazards of aluminum to plants, invertebrates, fish, and wildlife

    USGS Publications Warehouse

    Sparling, D.W.; Lowe, T.P.

    1996-01-01

    Aluminum is extremely common throughout the world and is innocuous under circumneutral or alkaline conditions. However, in acidic environments, it can be a maJor limiting factor to many plants and aquatic organisms. The greatest concern for toxicity in North America occurs in areas that are affected by wet and dry acid deposition, such as eastern Canada and the northeastern U.S. Acid mine drainage, logging, and water treatment plant effluents containing alum can be other maJor sources of Al. In solution, the metal can combine with several different agents to affect toxicity. In general, Al hydroxides and monomeric Al are the most toxic forms. Dissolved organic carbons, F, PO(3)3- and SO(4)2- ameliorate toxicity by reducing bioavailability. Elevated metal levels in water and soil can cause serious problems for some plants. Algae tend to be both acid- and Al tolerant and, although some species may disappear with reduced pH, overall algae productivity and biomass are seldom affected if pH is above 3.0. Aluminum and acid toxicity tend to be additive to some algae when pH is less than 4.5. Because the metal binds with inorganic P, it may reduce P availability and reduce productivity. Forest die-backs in North America involving red spruce, Fraser fir, balsam fir, loblolly pine, slash pine, and sugar maples have been ascribed to Al toxicity, and extensive areas of European forests have died because of the combination of high soil Al and low pH. Extensive research on crops has produced Al-resistant cultivars and considerable knowledge about mechanisms of and defenses against toxicity. Very low Al levels may benefit some plants, although the metal is not recognized as an essential nutrient. Hyperaccumulator species of plants may concentrate Al to levels that are toxic to herbivores. Toxicity in aquatic invertebrates is also acid dependent. Taxa such as Ephemeroptera, Plecoptera, and Cladocera are sensitive and may perish when Al is less than 1 mg.L-1 whereas dipterans, molluscs, and isopods seem to be tolerant. In Al-sensitive species, elevated levels (approximately 500 micrograms.L-1) affect ion regulation and respiratory efficiency. Toxicity tends to be greatest near a species` threshold of pH sensitivity. At lower pHs, Al may have a slight ameliorative effect by interfering with H+ transport across membranes. Aquatic invertebrates can accumulate very high levels of Al, but most of this appears to be through adsorption rather than assimilation. Aluminum concentrations may be as high as 5000 mg.kg-1 in insects and greater than 17,000 mg.kg-1 in other invertebrates.

  4. DDE remediation and degradation.

    PubMed

    Thomas, John E; Ou, Li-Tse; All-Agely, Abid

    2008-01-01

    DDT and its metabolites, DDD and DDE, have been shown to be recalcitrant to degradation. The parent compound, DDT, was used extensively worldwide starting in 1939 and was banned in the United States in 1973. The daughter compound, DDE, may result from aerobic degradation, abiotic dehydrochlorination, or photochemical decomposition. DDE has also occurred as a contaminant in commercial-grade DDT. The p,p'-DDE isomer is more biologically active than the o,p-DDE, with a reported half-life of -5.7 years. However, when DDT was repeatedly applied to the soil, the DDE concentration may remain unchanged for more than 20 yr. Remediation of DDE-contaminated soil and water may be done by several techniques. Phytoremediation involves translocating DDT, DDD, and DDE from the soil into the plant, although some aquatic species (duckweed > elodea > parrot feather) can transform DDT into predominantly DDD with some DDE being formed. Of all the plants that can uptake DDE, Cucurbita pepo has been the most extensively studied, with translocation values approaching "hyperaccumulation" levels. Soil moisture, temperature, and plant density have all been documented as important factors in the uptake of DDE by Cucurbita pepo. Uptake may also be influenced positively by amendments such as biosurfactants, mycorrhizal inoculants, and low molecular weight organic acids (e.g., citric and oxalic acids). DDE microbial degradation by dehalogenases, dioxygenases, and hydrolases occurs under the proper conditions. Although several aerobic degradation pathways have been proposed, none has been fully verified. Very few aerobic pure cultures are capable of fully degrading DDE to CO2. Cometabolism of DDE by Pseudomonas sp., Alicaligens sp., and Terrabacter sp. grown on biphenyl has been reported; however, not all bacterial species that produce biphenyl dioxygenase degraded DDE. Arsenic and copper inhibit DDE degradation by aerobic microorganisms. Similarly, metal chelates such as EDTA inhibit the breakdown of DDE by the extracellular lignolytic enzymes produced by white rot fungi. The addition of adjutants such as sodium ion, surfactants, and cellulose increased the rate of DDT aerobic or anaerobic degradation but did little to enhance the rate of DDE disappearance under anaerobic conditions. Only in the past decade has it been demonstrated that DDE can undergo reductive dechlorination under methanogenic and sulfidogenic conditions to form the degradation product DDMU, 1-chloro-2,2'-bis-(4'-chlorophenyl)ethane. The only pure culture reported to degrade DDE under anaerobic conditions was the denitrifier Alcaligens denitrificans. The degradation of DDE by this bacterium was enhanced by glucose, whereas biphenyl fumes had no effect. Abiotic remediation by DDE volatilization was enhanced by flooding and irrigation and deepplowing inhibited the volatilization. The use of zero-valent iron and surfactants in flooded soils enhanced DDT degradation but did not significantly alter the rate of DDE removal. Other catalysts (palladized magnesium, palladium on carbon, and nickel/aluminum alloys) degraded DDT and its metabolites, including DDE. However, these systems are often biphasic or involve explosive gases or both. Safer abiotic alternatives use UV light with titanium oxide or visible light with methylene green to degrade DDT, DDD, and DDE in aqueous or mixed solvent systems. Remediation and degradation of DDE in soil and water by phytoextraction, aerobic and anaerobic microorganisms, or abiotic methods can be accomplished. However, success has been limited, and great care must be taken that the method does not transfer the contaminants to another locale (by volatilization, deep plowing, erosion, or runoff) or to another species (by ingestion of accumulating plants or contaminated water). Although the remediation of DDT-, DDD-, and DDE-contaminated soil and water is beset with myriad problems, there remain many open avenues of research. PMID:18069646

  5. Accumulation of mercury in selected plant species grown in soils contaminated with different mercury compounds

    SciTech Connect

    Su, Yi; Han, Fengxiang; Shiyab, Safwan; Chen, Jian; Monts, David L.

    2007-07-01

    The objective of our research is to screen and search for suitable plant species for phyto-remediation of mercury-contaminated soil. Currently our effort is specifically focused on mercury removal from the U.S. Department of Energy (DOE) sites, where mercury contamination is a major concern. In order to cost effectively implement mercury remediation efforts, it is necessary now to obtain an improved understanding of biological means of removing mercury and mercury compounds.. Phyto-remediation is a technology that uses various plants to degrade, extract, contain, or immobilize contaminants from soil and water. In particular, phyto-extraction is the uptake of contaminants by plant roots and translocation within the plants to shoots or leaves. Contaminants are generally removed by harvesting the plants. We have investigated phyto-extraction of mercury from contaminated soil by using some of the known metal-accumulating plants since no natural plant species with mercury hyper-accumulating properties has yet been identified. Different natural plant species have been studied for mercury uptake, accumulation, toxicity and overall mercury removal efficiency. Various mercury compounds, such as HgS, HgCl{sub 2}, and Hg(NO{sub 3}){sub 2}, were used as contaminant sources. Different types of soil were examined and chosen for phyto-remediation experiments. We have applied microscopy and diffuse reflectance spectrometry as well as conventional analytical chemistry to monitor the phyto-remediation processes of mercury uptake, translocation and accumulation, and the physiological impact of mercury contaminants on selected plant species. Our results indicate that certain plant species, such as beard grass (Polypogon monospeliensis), accumulated a very limited amount of mercury in the shoots (<65 mg/kg), even though root mercury accumulation is significant (maximum 2298 mg/kg). Consequently, this plant species may not be suitable for mercury phyto-remediation. Other plant species, such as Indian mustard (Brassica juncea), a well-studied metal accumulator, exhibited severe chlorosis symptoms during some experiments. Among all the plant species studied, Chinese brake fern (Pteris vittata) accumulated significant amount of mercury in both roots and shoots and hence may be considered as a potential candidate for mercury phyto-extraction. During one experiment, Chinese brake ferns accumulated 540 mg/kg and 1469 mg/kg in shoots after 18 days of growing in soils treated with 500 parts-per-million (ppm) and 1000 ppm HgCl{sub 2} powder, respectively; no visual stress symptoms were observed. We also studied mercury phyto-remediation using aged soils that contained HgS, HgCl{sub 2}, or Hg(NO{sub 3}){sub 2}. We have found that up to hundreds of ppm mercury can be accumulated in the roots of Indian mustard plants grown with soil contaminated by mercury sulfide; HgS is assumed to be the most stable and also the predominant mercury form in flood plain soils. We have also started to investigate different mercury uptake mechanisms, such as root uptake of soil contaminant and foliar mercury accumulation from ambient air. We have observed mercury translocation from roots to shoot for Chinese fern and two Indian mustard varieties. (authors)

  6. Phyto extraction and accumulation of mercury in selected plant species grown in soil contaminated with different mercury compounds

    SciTech Connect

    Su, Y.; Han, F.; Shiyab, S.; Monts, D.L.

    2007-07-01

    The objective of our research is to screen and search for suitable plant species for phyto-remediation of mercury-contaminated soil. Currently our effort is specifically focused on mercury removal from the U.S. Department of Energy's (DOE) Oak Ridge Site, where mercury contamination is a major concern in the Y-12 Watershed area. In order to cost effectively implement those remediation efforts currently planned for FY09, it is necessary now to obtain an improved understanding of biological means of removing mercury and mercury compounds from the Oak Ridge ecosystem. Phyto-remediation is a technology that uses various plants to degrade, extract, contain, or immobilize contaminants from soil and water. In particular, phyto-extraction is the uptake of contaminants by plant roots and translocation within the plants to shoots or leaves. Contaminants are generally removed by harvesting the plants. We have investigated phyto-extraction of mercury from contaminated soil by using some of the known metal accumulating wild plants since no natural plant species with mercury hyper-accumulating properties has yet been identified. Different natural plant species have been studied for mercury uptake, accumulation, toxicity and overall mercury removal efficiency. Various mercury compounds, such as HgS, HgCl{sub 2} and Hg(NO{sub 3}){sub 2}, were used as contaminant sources. Different types of soil were examined and chosen for phyto-remediation experiments. We have applied microscopy and diffuse reflectance spectrometry as well as conventional analytical chemistry to monitor the phyto-remediation processes of mercury uptake, translocation and accumulation; and the physiological impact of mercury contaminants on selected plant species. Our results indicate that certain plant species, such as beard grass (Polypogon monospeliensis), accumulated a very limited amount of mercury in the shoots (<65 mg/kg), even though root mercury accumulation is significant (maximum 2298 mg/kg). Consequently, this plant species may not be suitable for mercury phyto-remediation. Other plant species, such as Indian mustard (Brassica juncea), a well-studied metal accumulator, exhibited severe chlorosis symptoms during some experiments. Among all the plant species studied, Chinese brake fern (Pteris vittata) accumulated significant amount of mercury in both roots and shoots and hence may be considered as a potential candidate for mercury phyto-extraction. During one experiment, brake ferns accumulated 540 mg/kg and 1469 mg/kg in shoots after 18 days of growing in soils treated with 500 ppm and 1000 ppm HgCl{sub 2} powder, respectively; no visual stress symptoms were observed. We also studied mercury phyto-remediation using aged soils that contaminated HgS, HgCl{sub 2}, and Hg(NO{sub 3}){sub 2}. We have found that up to hundreds of ppm mercury can be accumulated in the roots of Indian mustard plants grown with soil contaminated by mercury sulfide; HgS is assumed to be the most stable and also the predominant mercury form in Oak Ridge flood plain soils. We have also started to investigate different mercury uptake mechanisms, such as root uptake of soil contaminant and foliar mercury accumulation from ambient air. (authors)

  7. Influence of fertilization on the capability of rice resistance to diseases

    NASA Astrophysics Data System (ADS)

    Hu, Xue-Feng; Chang, Yue-Ya; Jiang, Ying; Yan, Xiao-Juan; Luo, Fan

    2013-04-01

    Organic cultivation of rice requires no use of any agricultural chemicals during the entire period of growth, and so the rice's self-prevention of diseases and pests is vitally important. A field experiment was carried out to study the possible influence of different fertilization on the capability of rice resistance to diseases and pests. A rice variety used for this experiment is Jia-He 218. Four treatments (A, B, C and D) were designed: A is a control, without using any fertilizers; B, after manuring of green azolla, 0.67 kg/m2; C, after manuring of rapeseed cake, 0.30 kg/m2; D, after fertilizing of ammonium bicarbonate, 0.025 kg/m2, and urea, 0.025 kg/m2. The experiment plot is 66.7 m2, with three replicates. The results indicated that the fertilization patterns significantly influence the growth of rice seedlings: The heights by A, B, C and D are 37 cm, 40 cm , 42 cm and 45 cm on average, respectively; the spike numbers, 45, 65, 73 and 75, respectively; chlorophyll contents in leaves, 1.84 mg/g, 2.42 mg/g, 3.02 mg/g and 3.97 mg/g, respectively. The rice with the different fertilization also varies in nutrient concentration in leaves: NH4-N concentration in leaves by A, B, C and D is 47.5 mg/kg, 61.1 mg/kg, 74.7 mg/kg and 135.8 mg/kg on average, respectively; NO3-N in leaves, 138.9 mg/kg, 185.2 mg/kg, 154.3 mg/kg and 293.2 mg/kg, respectively. The fertilization patterns, moreover, show a significant influence on the incidence of diseases and pests to rice seedlings: The incidence of rice cnaphalocrocis medinalis by A, B, C and D is 1.33 %, 1.50 %, 1.75 % and 89.0 % on average, respectively; that of bacterial leaf blight, 0, 1.25 %, 1.75 % and 85.0 %, respectively; number of rice planthopper in each plant, 20, 21, 21 and 30, respectively. As a result, the yield of rice grain by A, B, C and D is 4540 kg/ha, 4606 kg/ha, 4503 kg/ha and 4092 kg/ha on average, respectively. In conclusion, the rice seedlings treated with chemical fertilizers grow large and tender, which makes it more vulnerable to diseases and pests, resulting in low grain yield. In addition, its immune system capability might be significantly reduced by hyper-accumulation of free nutrients in leaves or stems due to excessive application of chemical fertilizers, and thus leaving it more seriously attacked by diseases and pests.

  8. Soil and plant contamination by lead mining in Bellmunt (Western Mediterranean Area)

    NASA Astrophysics Data System (ADS)

    Bech, Jaume; Duran, Paola; Barceló, Juan; Roca, Núria; Tume, Pedro; Poschenrieder, Charlotte

    2010-05-01

    Galena has been mined in Bellmunt (Priorat, Western Mediterranean Area) since ancient times until 1972. While sediment pollution originated by the mining activity in the Ebro river passing the region has been investigated (Ferré, 2007), the local impact on soils and plants has received little attention. Here we report the first results on the concentrations of major metal contaminants and antimony in soils and representative plants from 5 selected sites with different pollutant burdens around the mining area. Both total (HNO3, HF, HClO4 digest) and extractable (EDTA) soil concentrations were studied. The range of total and extractable soil values in mgkg-1 is as follows: Sb 9.7-31 and 2.4-7.2; Cu: 89-823 and 20-62; Pb: 19-39 and 18-33; Zn: 318-989 and 79-287 mg•kg-1, respectively). Soils had alkaline pH (7.7-8.2), organic matter contents ranging from 0.8 to 2.4%, and a sandy-loam or a loamy-sand texture. All analysed plant species showed enhanced root and shoot concentrations of Pb, Cu, Zn and Sb when growing on the more polluted soils, and all but one restricted the translocation of metals from roots to shoots exhibiting shoot/root concentration ratios lower than unity. A notably exception was Moricandia moricandioides. This species of the Brassicaceae family exhibited higher Zn concentrations in the shoots than in the roots at all sampling sites yielding shoot/root concentration ratios up to 5.5. This metal accumulation pattern was only observed for Zn and not for other analysed metal contaminants. The concentrations of other, poorly mobile metals, like Pb or Cu were always higher in roots than in shoots (e.g. Pb shoot/root ratios ranged from 0.12 to 0.41). Taking into account the high Pb burden of the soil samples and these low shoot/root Pb ratios, it can be excluded that the particular Zn accumulation pattern of Moricandia moricandioides was biased by soil contamination of shoot samples. To the best of our knowledge, this is the first report of a Zn accumulation behaviour in a Moricandia species. The soil-to-shoot transfer factors (shoot Zn conc/total soil conc.) for this species were, however, relatively low ranging from 0.3 to 1.3. Two main reasons for this could be 1) the fact that real total Zn soil concentrations after HF attack and not pseudototal metal concentrations were analysed in the present study and 2) the relatively high pH of the soils which could considerably hamper Zn bioavailability. Further studies are required to confirm the possible Zn (hyper)accumulator character of Moricandia moricandioides (Boiss.) Heyw. [M. ramburii Webb]. Reference: Ferré, N. 2007 Nivells de metals pesants a la conca Catalana del riu Ebre. Avaluació del risc per la población i l'ecosistema. Universitat Rovira Virgili. ISBN 978-84-691-0371-5. Acknowledgement: Supported by BFU2007-60332/BFI