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Sample records for hyperaccumulator thlaspi caerulescens1w

  1. Constitutively Elevated Salicylic Acid Signals Glutathione-Mediated Nickel Tolerance in Thlaspi Nickel Hyperaccumulators1

    PubMed Central

    Freeman, John L.; Garcia, Daniel; Kim, Donggiun; Hopf, Amber; Salt, David E.

    2005-01-01

    Progress is being made in understanding the biochemical and molecular basis of nickel (Ni)/zinc (Zn) hyperaccumulation in Thlaspi; however, the molecular signaling pathways that control these mechanisms are not understood. We observed that elevated concentrations of salicylic acid (SA), a molecule known to be involved in signaling induced pathogen defense responses in plants, is a strong predictor of Ni hyperaccumulation in the six diverse Thlaspi species investigated, including the hyperaccumulators Thlaspi goesingense, Thlaspi rosulare, Thlaspi oxyceras, and Thlaspi caerulescens and the nonaccumulators Thlaspi arvense and Thlaspi perfoliatum. Furthermore, the SA metabolites phenylalanine, cinnamic acid, salicyloyl-glucose, and catechol are also elevated in the hyperaccumulator T. goesingense when compared to the nonaccumulators Arabidopsis (Arabidopsis thaliana) and T. arvense. Elevation of free SA levels in Arabidopsis, both genetically and by exogenous feeding, enhances the specific activity of serine acetyltransferase, leading to elevated glutathione and increased Ni resistance. Such SA-mediated Ni resistance in Arabidopsis phenocopies the glutathione-based Ni tolerance previously observed in Thlaspi, suggesting a biochemical linkage between SA and Ni tolerance in this genus. Intriguingly, the hyperaccumulator T. goesingense also shows enhanced sensitivity to the pathogen powdery mildew (Erysiphe cruciferarum) and fails to induce SA biosynthesis after infection. Nickel hyperaccumulation reverses this pathogen hypersensitivity, suggesting that the interaction between pathogen resistance and Ni tolerance and hyperaccumulation may have played a critical role in the evolution of metal hyperaccumulation in the Thlaspi genus. PMID:15734913

  2. Increased Glutathione Biosynthesis Plays a Role in Nickel Tolerance in Thlaspi Nickel HyperaccumulatorsW?

    PubMed Central

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

    2004-01-01

    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

  3. 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

  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. 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...

  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. 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...

  8. 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...

  9. 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.

  10. Bacterial Communities Associated with Flowering Plants of the Ni Hyperaccumulator Thlaspi goesingense

    PubMed Central

    Idris, Rughia; Trifonova, Radoslava; Puschenreiter, Markus; Wenzel, Walter W.; Sessitsch, Angela

    2004-01-01

    Thlaspi goesingense is able to hyperaccumulate extremely high concentrations of Ni when grown in ultramafic soils. Recently it has been shown that rhizosphere bacteria may increase the heavy metal concentrations in hyperaccumulator plants significantly, whereas the role of endophytes has not been investigated yet. In this study the rhizosphere and shoot-associated (endophytic) bacteria colonizing T. goesingense were characterized in detail by using both cultivation and cultivation-independent techniques. Bacteria were identified by 16S rRNA sequence analysis, and isolates were further characterized regarding characteristics that may be relevant for a beneficial plant-microbe interactionNi tolerance, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase and siderophore production. In the rhizosphere a high percentage of bacteria belonging to the Holophaga/Acidobacterium division and ?-Proteobacteria were found. In addition, high-G+C gram-positive bacteria, Verrucomicrobia, and microbes of the Cytophaga/Flexibacter/Bacteroides division colonized the rhizosphere. The community structure of shoot-associated bacteria was highly different. The majority of clones affiliated with the Proteobacteria, but also bacteria belonging to the Cytophaga/Flexibacter/Bacteroides division, the Holophaga/Acidobacterium division, and the low-G+C gram-positive bacteria, were frequently found. A high number of highly related Sphingomonas 16S rRNA gene sequences were detected, which were also obtained by the cultivation of endophytes. Rhizosphere isolates belonged mainly to the genera Methylobacterium, Rhodococcus, and Okibacterium, whereas the majority of endophytes showed high levels of similarity to Methylobacterium mesophilicum. Additionally, Sphingomonas spp. were abundant. Isolates were resistant to Ni concentrations between 5 and 12 mM; however, endophytes generally tolerated higher Ni levels than rhizosphere bacteria. Almost all bacteria were able to produce siderophores. Various strains, particularly endophytes, were able to grow on ACC as the sole nitrogen source. PMID:15128517

  11. Bacterial communities associated with flowering plants of the Ni hyperaccumulator Thlaspi goesingense.

    PubMed

    Idris, Rughia; Trifonova, Radoslava; Puschenreiter, Markus; Wenzel, Walter W; Sessitsch, Angela

    2004-05-01

    Thlaspi goesingense is able to hyperaccumulate extremely high concentrations of Ni when grown in ultramafic soils. Recently it has been shown that rhizosphere bacteria may increase the heavy metal concentrations in hyperaccumulator plants significantly, whereas the role of endophytes has not been investigated yet. In this study the rhizosphere and shoot-associated (endophytic) bacteria colonizing T. goesingense were characterized in detail by using both cultivation and cultivation-independent techniques. Bacteria were identified by 16S rRNA sequence analysis, and isolates were further characterized regarding characteristics that may be relevant for a beneficial plant-microbe interaction-Ni tolerance, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase and siderophore production. In the rhizosphere a high percentage of bacteria belonging to the Holophaga/Acidobacterium division and alpha-Proteobacteria were found. In addition, high-G+C gram-positive bacteria, Verrucomicrobia, and microbes of the Cytophaga/Flexibacter/Bacteroides division colonized the rhizosphere. The community structure of shoot-associated bacteria was highly different. The majority of clones affiliated with the Proteobacteria, but also bacteria belonging to the Cytophaga/Flexibacter/Bacteroides division, the Holophaga/Acidobacterium division, and the low-G+C gram-positive bacteria, were frequently found. A high number of highly related Sphingomonas 16S rRNA gene sequences were detected, which were also obtained by the cultivation of endophytes. Rhizosphere isolates belonged mainly to the genera Methylobacterium, Rhodococcus, and Okibacterium, whereas the majority of endophytes showed high levels of similarity to Methylobacterium mesophilicum. Additionally, Sphingomonas spp. were abundant. Isolates were resistant to Ni concentrations between 5 and 12 mM; however, endophytes generally tolerated higher Ni levels than rhizosphere bacteria. Almost all bacteria were able to produce siderophores. Various strains, particularly endophytes, were able to grow on ACC as the sole nitrogen source. PMID:15128517

  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. Nickel and Cobalt Resistance Engineered in Escherichia coli by Overexpression of Serine Acetyltransferase from the Nickel Hyperaccumulator Plant Thlaspi goesingense

    PubMed Central

    Freeman, John L.; Persans, Michael W.; Nieman, Ken; Salt, David E.

    2005-01-01

    The overexpression of serine acetyltransferase from the Ni-hyperaccumulating plant Thlaspi goesingense causes enhanced nickel and cobalt resistance in Escherichia coli. Furthermore, overexpression of T. goesingense serine acetyltransferase results in enhanced sensitivity to cadmium and has no significant effect on resistance to zinc. Enhanced nickel resistance is directly related to the constitutive overactivation of sulfur assimilation and glutathione biosynthesis, driven by the overproduction of O-acetyl-l-serine, the product of serine acetyltransferase and a positive regulator of the cysteine regulon. Nickel in the serine acetyltransferase-overexpressing strains is not detoxified by coordination or precipitation with sulfur, suggesting that glutathione is involved in reducing the oxidative damage imposed by nickel. PMID:16332856

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hyperaccumulation was a term first coined by Brooks for plants that are endemic to metalliferous soils and are able to tolerate and accumulate large amounts of metals in their above ground tissues. Of the nearly 90 metal hyperaccumulating species in the Brassicaceae family, two species in particula...

  15. Colonisation of a Zn, Cd and Pb hyperaccumulator Thlaspi praecox Wulfen with indigenous arbuscular mycorrhizal fungal mixture induces changes in heavy metal and nutrient uptake.

    PubMed

    Vogel-Mikus, Katarina; Pongrac, Paula; Kump, Peter; Necemer, Marijan; Regvar, Marjana

    2006-01-01

    Plants of the Zn, Cd and Pb hyperaccumulator Thlaspi praecox Wulfen (Brassicaceae) inoculated or not with indigenous arbuscular mycorrhizal (AM) fungal mixture were grown in a highly Cd, Zn and Pb contaminated substrate in order to evaluate the functionality of symbiosis and assess the possible impact of AM colonisation on heavy metal uptake and tolerance. The results suggest AM development in the metal hyperaccumulating T. praecox is favoured at elevated nutrient demands, e.g. during the reproductive period. AM colonisation parameters positively correlated with total soil Cd and Pb. Colonised plants showed significantly improved nutrient and a decreased Cd and Zn uptake as revealed by TRXRF, thus confirming the functionality of the symbiosis. Reduced heavy metal uptake, especially at higher soil metal contents, indicates a changed metal tolerance strategy in colonised T. praecox plants. This is to our knowledge the first report on AM colonisation of the Zn, Cd and Pb hyperaccumulator T. praecox in a greenhouse experiment. PMID:15998561

  16. Influence of Iron Status on Cadmium and Zinc Uptake by Different Ecotypes of the Hyperaccumulator Thlaspi caerulescens1

    PubMed Central

    Lombi, Enzo; Tearall, Kathryn L.; Howarth, Jonathan R.; Zhao, Fang-Jie; Hawkesford, Malcolm J.; McGrath, Steve P.

    2002-01-01

    We have previously identified an ecotype of the hyperaccumulator Thlaspi caerulescens (Ganges), which is far superior to other ecotypes (including Prayon) in Cd uptake. In this study, we investigated the effect of Fe status on the uptake of Cd and Zn in the Ganges and Prayon ecotypes, and the kinetics of Cd and Zn influx using radioisotopes. Furthermore, the T. caerulescens ZIP (Zn-regulated transporter/Fe-regulated transporter-like protein) genes TcZNT1-G and TcIRT1-G were cloned from the Ganges ecotype and their expression under Fe-sufficient and -deficient conditions was analyzed. Both short- and long-term studies revealed that Cd uptake was significantly enhanced by Fe deficiency only in the Ganges ecotype. The concentration-dependent kinetics of Cd influx showed that the Vmax of Cd was 3 times greater in Fe-deficient Ganges plants compared with Fe-sufficient plants. In Prayon, Fe deficiency did not induce a significant increase in Vmax for Cd. Zn uptake was not influenced by the Fe status of the plants in either of the ecotypes. These results are in agreement with the gene expression study. The abundance of ZNT1-G mRNA was similar between the Fe treatments and between the two ecotypes. In contrast, abundance of the TcIRT1-G mRNA was greatly increased only in Ganges root tissue under Fe-deficient conditions. The present results indicate that the stimulatory effect of Fe deficiency on Cd uptake in Ganges may be related to an up-regulation in the expression of genes encoding for Fe2+ uptake, possibly TcIRT1-G. PMID:11950984

  17. Influence of the zinc hyperaccumulator Thlaspi caerulescens J. & C. Presl. and the nonmetal accumulator Trifolium pratense L. on soil microbial populations.

    PubMed

    Delorme, T A; Gagliardi, J V; Angle, J S; Chaney, R L

    2001-08-01

    Metal hyperaccumulator plants like Thlaspi caerulescens J. & C. Presl. are used for phytoremediation of contaminated soils. Since little is known about the rhizosphere of hyperaccumulators, the influence of T. caerulescens was compared with the effects of Trifolium pratense L. on soil microbes. High- and low-metal soils were collected near a zinc smelter in Palmerton, Penn. Soil pH was adjusted to 5.8 and 6.8 by the addition of Ca(OH)2. Liming increased bacterial populations and decreased metal toxicity to levels allowing growth of both plants. The effects of the plants on total (culturable) bacteria, total fungi, as well as cadmium- and zinc-resistant populations were assessed in nonrhizosphere and rhizosphere soil. Both plants increased microbial populations in rhizosphere soil compared with nonrhizosphere soil. Microbial populations were higher in soils planted with T. pratense, but higher ratios of metal-resistant bacteria were found in the presence of T. caerulescens. We hypothesize that T. caerutescens acidifies its rhizosphere. Soil acidification in the rhizosphere of T. caerulescens would affect metal uptake by increasing available metals around the roots and consequently, increase the selection for metal-resistant bacteria. Soil acidification may be part of the hyperaccumulation process enhancing metal uptake from soil. PMID:11575505

  18. [Stoichiometry of multi-elements in the zinc-cadmium hyperaccumulator Thlaspi caerulescens grown hydroponically under different zinc concentrations determined by ICP-AES].

    PubMed

    Han, Wen-xuan; Xu, Yi-ming; Du, Wei; Tang, Ao-han; Jiang, Rong-feng

    2009-09-01

    Thlaspi caerulescens is commonly known as a zinc (Zn) and cadmium (Cd) hyperaccumulator, which can be used to clean up the Zn- and/or Cd-contaminated soil. However, it is unclear whether high soil Zn concentrations will stimulate undue accumulations of other elements to such an extent as to cause the nutrient unbalance in the soil. To address this question, the inductively coupled plasma-atomic emission spectrometry (ICP-AES) was employed to investigate the effect of Zn on the stoichiometry of Zn, Cd, K, P, Mg, Ca, Fe, Mn and Cu in T. caerulescens (Ganges ecotype) exposed to low, middle and high Zn concentrations (5, 50 and 500 micromol x L(-1), respectively) in a hydroponic experiment. The results showed that there were no significant variations in contents of Cd, K, P, Mg, Ca, Fe, Mn and Cu in the shoot of T. caerulescens, however, the Zn content in the shoot and root with 500 mciromol x L(-1) Zn treatment increased as much as 13 times higher than that with low Zn exposure, indicating that the plant is capable of Zn hyperaccumulating. The authors' study suggests that it is improbable to induce soil nutrient unbalance when T. caerulescensis (Ganges) is used for phytoremediation of Zn-contaminated soil, in that over-uptake of nutrient elements from the soil other than Zn was not observed, at least for the elements K, P, Mg, Ca, Fe, Mn and Cu. PMID:19950676

  19. 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...

  20. TcYSL3, a member of the YSL gene family from the hyper-accumulator Thlaspi caerulescens, encodes a nicotianamine-Ni/Fe transporter.

    PubMed

    Gendre, Delphine; Czernic, Pierre; Conéjéro, Geneviève; Pianelli, Katia; Briat, Jean-François; Lebrun, Michel; Mari, Stéphane

    2007-01-01

    The two main features of plant hyper-accumulator species are the massive translocation of heavy metal ions to the aerial parts and their tolerance to such high metal concentrations. Recently, several lines of evidence have indicated a role for nicotianamine (NA) in metal homeostasis, through the chelation and transport of NA-metal complexes. The function of transport of NA-metal chelates, required for the loading and unloading of vessels, has been assigned to the Yellow Stripe 1 (YSL)-Like family of proteins. We have characterized three YSL genes in Thlaspi caerulescens in the context of hyper-accumulation. The three YSL genes are expressed at high rates compared with their Arabidopsis thaliana homologs but with distinct patterns. While TcYSL7 was highly expressed in the flowers, TcYSL5 was more highly expressed in the shoots, and the expression of TcYSL3 was equivalent in all the organs tested. In situ hybridizations have shown that TcYSL7 and TcYSL5 are expressed around the vasculature of the shoots and in the central cylinder in the roots. The exposure to heavy metals (Zn, Cd, Ni) does not affect the high and constitutive expression of the TcYSL genes. Finally, we have demonstrated by mutant yeast complementation and uptake measurements that TcYSL3 is an Fe/Ni-NA influx transporter. This work provides therefore molecular, histological and biochemical evidence supporting a role for YSL transporters in the overall scheme of NA and NA-metal, particularly NA-Ni, circulation in a metal hyper-accumulator plant. PMID:17144893

  1. 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.

  2. Cd induced redistribution of elements within leaves of the Cd/Zn hyperaccumulator Thlaspi praecox as revealed by micro-PIXE

    NASA Astrophysics Data System (ADS)

    Pongrac, Paula; Vogel-Miku, Katarina; Vavpeti?, Primo; Tratnik, Janja; Regvar, Marjana; Sim?i?, Jurij; Grlj, Nataa; Pelicon, Primo

    2010-06-01

    A detailed localisation of elements within leaf tissues of hydroponically grown Cd/Zn hyperaccumulator Thlaspi praecox (Brassicaceae) was determined by micro-PIXE at Joef Stefan Institute (Ljubljana, Slovenia) in order to study accumulation patterns of Cd and other elements in the case of a single metal (Cd) pollution. Plants were treated with increasing concentrations of Cd in the solution (0 (control), 1, 10 and 100 ?M). As expected, concentration of Cd in the leaves gradually increased with Cd concentration in the solution. In order to reveal the main Cd storage compartment space within the leaves a relative element distribution (pool) was calculated based on concentrations of elements in specific leaf tissues and their weight portions. Where present at detectable levels, Cd accumulated in the epidermal tissues (at 10 ?M), but the contribution of epidermal pool decreased with increasing Cd concentration in solution (at 100 ?M). The opposite was observed for the mesophyll pool. In addition, in Cd treated plants, a significant decrease in mesophyll Fe pool and an increase in the epidermal Fe pool were observed. Similar effect was seen for Mn pool at 100 ?M Cd treatment accompanied by increasing Zn epidermal pool with increasing Cd in nutrient solution. Altogether these results indicate repartitioning of essential mesophyll cation pools (e.g., Fe, Mn and possibly Zn) when increasing Cd contents, that are instead more intensively stored in the epidermal cells. These results confirmed micro-PIXE as effective and powerful technique providing essential information on metal localisation, repartitioning and major elemental stores in plants on the tissue levels that were not accessible using classical analytical techniques and thus complementing our current understanding of plant metal tolerance mechanisms as a whole.

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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.'

  10. Metal Hyperaccumulation Armors Plants against Disease

    PubMed Central

    Fones, Helen; Davis, Calum A. R.; Rico, Arantza; Fang, Fang; Smith, J. Andrew C.; Preston, Gail M.

    2010-01-01

    Metal hyperaccumulation, in which plants store exceptional concentrations of metals in their shoots, is an unusual trait whose evolutionary and ecological significance has prompted extensive debate. Hyperaccumulator plants are usually found on metalliferous soils, and it has been proposed that hyperaccumulation provides a defense against herbivores and pathogens, an idea termed the elemental defense hypothesis. We have investigated this hypothesis using the crucifer Thlaspi caerulescens, a hyperaccumulator of zinc, nickel, and cadmium, and the bacterial pathogen Pseudomonas syringae pv. maculicola (Psm). Using leaf inoculation assays, we have shown that hyperaccumulation of any of the three metals inhibits growth of Psm in planta. Metal concentrations in the bulk leaf and in the apoplast, through which the pathogen invades the leaf, were shown to be sufficient to account for the defensive effect by comparison with in vitro doseresponse curves. Further, mutants of Psm with increased and decreased zinc tolerance created by transposon insertion had either enhanced or reduced ability, respectively, to grow in high-zinc plants, indicating that the metal affects the pathogen directly. Finally, we have shown that bacteria naturally colonizing T. caerulescens leaves at the site of a former leadzinc mine have high zinc tolerance compared with bacteria isolated from non-accumulating plants, suggesting local adaptation to high metal. These results demonstrate that the disease resistance observed in metal-exposed T. caerulescens can be attributed to a direct effect of metal hyperaccumulation, which may thus be functionally analogous to the resistance conferred by antimicrobial metabolites in non-accumulating plants. PMID:20838462

  11. 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...

  12. Characterization of the high affinity Zn transporter from Noccaea caerulescens, NcZNT1, and dissection of its promoter for its role in Zn uptake and hyperaccumulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this paper, we conducted a detailed analysis of the ZIP family transporter, NcZNT1, in the Zn/Cd hyperaccumulating plant species, Noccaea caerulescens, formerly known as Thlaspi caerulescens. NcZNT1 was previously suggested to be the primary root Zn/Cd uptake transporter. Both a characterization ...

  13. Comparative transcriptome analysis of the metal hyperaccumulator Noccaea caerulescens

    PubMed Central

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

  14. 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.'

  15. Evolutionary aspects of elemental hyperaccumulation.

    PubMed

    Cappa, Jennifer J; Pilon-Smits, Elizabeth A H

    2014-02-01

    Hyperaccumulation is the uptake of one or more metal/metalloids to concentrations greater than 50-100 those of the surrounding vegetation or 100-10,000mg/kg dry weight depending on the element. Hyperaccumulation has been documented in at least 515 taxa of angiosperms. By mapping the occurrence of hyperaccumulators onto the angiosperm phylogeny, we show hyperaccumulation has had multiple origins across the angiosperms. Even within a given order, family or genus, there are typically multiple origins of hyperaccumulation, either for the same or different elements. We address which selective pressures may have led to the evolution of hyperaccumulation and whether there is evidence for co-evolution with ecological partners. Considerable evidence supports the elemental-defense hypothesis, which states that hyperaccumulated elements protect the plants from herbivores and pathogens. There is also evidence that hyperaccumulation can result in drought stress protection, allelopathic effects or physiological benefits. In many instances, ecological partners of hyperaccumulators have evolved resistance to the hyperaccumulated element, indicating co-evolution. Studies on the molecular evolution of hyperaccumulation have pinpointed gene duplication as a common cause of increased metal transporter abundance. Hypertolerance to the hyperaccumulated element often relies upon chelating agents, such as organic acids (e.g., malate, citrate) or peptide/protein chelators that can facilitate transport and sequestration. We conclude the review with a summary and suggested future directions for hyperaccumulator research. PMID:24463931

  16. 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.

  17. Nickel, Zn and Cd localisation in seeds of metal hyperaccumulators using ?-PIXE spectroscopy

    NASA Astrophysics Data System (ADS)

    Kachenko, Anthony G.; Bhatia, Naveen P.; Siegele, Rainer; Walsh, Kerry B.; Singh, Balwant

    2009-06-01

    Metal hyperaccumulators are a rare group of plant species that accumulate exceptionally high concentrations of metals in above ground tissues without showing symptoms of phytotoxicity. Quantitative localisation of the accumulated metals in seed tissues is of considerable interest to help understand the eco-physiology of these unique plant species. We investigated the spatial localisation of metals within seeds of Ni hyperaccumulating Hybanthus floribundus subsp. adpressus, H. floribundus subsp. floribundus and Pimelea leptospermoides and dual-metal (Cd and Zn) hyperaccumulating Thlaspi caerulescens using quantitative micro-proton induced X-ray emission (?-PIXE) spectroscopy. Intact seeds were hand-sectioned, sandwiched between Formvar films and irradiated using the 3 MeV high energy heavy ion microprobe at ANSTO. Elemental maps of whole H. floribundus subsp. adpressus seeds showed an average Ni concentration of 5.1 10 3 mg kg -1 dry weight (DW) with highest Ni concentration in cotyledonary tissues (7.6 10 3 mg kg -1 DW), followed by the embryonic axis (4.4 10 3 mg kg -1 DW). Nickel concentration in whole H. floribundus subsp. floribundus seeds was 3.5 10 2 mg kg -1 DW without a clear pattern of Ni localisation. The average Ni concentration in whole P. leptospermoides seeds was 2.6 10 2 mg kg -1 DW, and Ni was preferentially localised in the embryonic axis (4.3 10 2 mg kg -1 DW). In T. caerulescens, Cd concentrations were similar in cotyledon (4.5 10 3 mg kg -1 DW) and embryonic axis (3.3 10 3 mg kg -1 DW) tissues, whereas Zn was highest in cotyledonary tissues (1.5 10 3 mg kg -1 DW). In all species, the presence of the accumulated metal within the cotyledonary and embryonic axis tissues indicates that the accumulated metal was able to move apoplastically within the seed.

  18. 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 ...

  19. 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

  20. 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

  1. PHYTOEXTRACTION OF HEAVY METALS WITH HYPERACCUMULATOR PLANTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    When soils contain metals at high enough levels to comprise risk thru food-chain or soil ingestion, some methods must be applied to alleviate the risk, or the land use must be constrained. One approach to remediate risks from some metals is phytoextraction using hyperaccumulator plants. These remark...

  2. Thermoinductive regulation of gibberellin metabolism in Thlaspi arvense L

    SciTech Connect

    Hazebroek, J.P.; Metzger, J.D. )

    1990-09-01

    Field pennycress (Thlaspi arvense L.) is a winter annual crucifer with a cold requirement for stem elongation and flowering. In the present study, the metabolism of exogenous ({sup 2}H)-ent-kaurenoic acid (KA) and ({sup 14}C)-gibberellin A{sub 12}-aldehyde (GA{sub 12}-aldehyde) was compared in thermo- and noninduced plants. Thermoinduction greatly altered both quantitative and qualitative aspects of ({sup 2}H)-KA metabolism in the shoot tips. The rate of disappearance of the parent compound was much greater in thermoinduced shoot tips. These results are consistent with the suggestion that the conversion of KA in to GAs is under thermoinductive control only in the shoot tip, the site of perception for thermoinductive temperatures in field pennycress. There were essentially no differences in the qualitative or quantitative distribution of metabolites formed following the application of ({sup 14}C)GA{sub 12}-aldehyde to the shoot tips of thermo- or noninduced plants. Thus, the apparent thermoinductive regulation of the KA metabolism into GAs is probably limited to the two metabolic steps involved in converting KA to GA{sub 12}-aldehyde.

  3. Registration of Katelyn Thlaspi arvense L. (Pennycress) with improved nondormant traits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Katelyn (Reg. No. GP-35, PI 673443) pennycress (Thlaspi arvense L.) was publicly released by the USDA-ARS in 2014 as part of a new crop improvement program. Katelyn was developed by two generations of mass selection based on the germination response of freshly harvested pennycress seeds. The origina...

  4. 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...

  5. Preparation, composition and functional properties of pennycress (Thlaspi arvense L.) seed protein isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study evaluated two methods, saline extraction (SE) and conventional acid precipitation (AP), to recover proteins from pennycress (Thlaspi arvense L.) seed meal. SE was done using 0.1 M NaCl at 50ºC while AP involved alkaline extraction (pH 10) first followed by protein precipitation at pH 4. C...

  6. 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...

  7. 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...

  8. Enrichment of erucic acid from pennycress (Thlaspi arvense L.) seed oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress (Thlaspi arvense) is a winter annual that has a wide geographic distribution and a growth habitat that makes it suitable for an off-season rotation between corn and soybeans in much of the Midwestern United States. Pennycress seed contains 36% oil with 36.6% erucic acid content. There are...

  9. Extraction, composition and functional properties of pennycress (Thlaspi arvense L.) press cake protein

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study compared two methods for extracting the protein in pennycress (Thlaspi arvense L.) press cake and determined the composition and functional properties of the protein products. Proteins in pennycress press cake were extracted by using the conventional alkali solubilization-acid precipitati...

  10. Composition and Physical Properties of Cress (Lepidium sativum L.) and Field Pennycress (Thlaspi arvense L.) Oils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fatty acid profile and tocopherol, and phytosterol contents of crude cress (Lepidium sativum L.) and field pennycress (Thlaspi arvense L.) oils are reported, along with yields from the corresponding seeds. The physical properties of these oils were also determined, which included oxidative stab...

  11. Biofumigant compounds released by field pennycress (Thlaspi arvense) seedmeal.

    PubMed

    Vaughn, Steven F; Isbell, Terry A; Weisleder, David; Berhow, Mark A

    2005-01-01

    Defatted field pennycress (Thlaspi arvense L.) seedmeal was found to completely inhibit seedling germination/emergence when added to a sandy loam soil containing wheat (Triticum aestivum L.) and arugula [Eruca vesicaria (L.) Cav. subsp. sativa (Mill.) Thell.] seeds at levels of 1.0% w/w or higher. Covering the pots with Petri dishes containing the soil-seedmeal mixture decreased germination of both species at the lowest application rate (0.5% w/w), suggesting that the some of the phytotoxins were volatile. CH2Cl2, MeOH, and water extracts of the wetted seedmeal were bioassayed against wheat and sicklepod (Senna obtusifolia (L.) H. S. Irwin & Barneby) radicle elongation. Only the CH2Cl2 extract was strongly inhibitory to both species. Fractionation of the CH2Cl2 extract yielded two major phytotoxins, identified by gas chromatography-mass spectrometry and NMR as 2-propen-1-yl (allyl) isothiocyanate (AITC) and allyl thiocyanate (ATC), which constituted 80.9 and 18.8%, respectively, of the active fraction. When seeds of wheat, arugula and sicklepod were exposed to volatilized AITC and ATC, germination of all three species was completely inhibited by both compounds at concentrations of 5 ppm or less. In field studies, where seedmeal was applied at 0.50, 1.25, and 2.50 kg/m2 and tarped with black plastic mulch, all of the treatments significantly reduced dry weight of bioassay plants compared to the tarped control, with the highest seedmeal rate decreasing dry matter to less than 10% of the control 30 d after seedmeal application. Field pennycress seedmeal appears to offer excellent potential as a biofumigant for high-value horticultural crops for both conventional and organic growers. PMID:15839488

  12. 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...

  13. 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

  14. 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, ...

  15. Growth environment but not seed position on the parent plant affect seed germination of two Thlaspi arvense L. populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thlaspi arvense L. is a common weed found in most temperate regions throughout the world that also shows excellent potential for domestication as an oilseed crop. The complexity of T. arvense seed dormancy presently makes it difficult to manage as a weed or oilseed crop. Therefore, a better understa...

  16. 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...

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

    PubMed

    Becerra-Castro, C; Prieto-Fernndez, 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

  18. Plant homeostasis of foliar manganese sinks: specific variation in hyperaccumulators.

    PubMed

    Fernando, Denise R; Woodrow, Ian E; Baker, Alan J M; Marshall, Alan T

    2012-11-01

    Plant manganese (Mn) hyperaccumulation provides unusual insight into homeostasis of this essential micronutrient, in particular its excessive storage in shoot tissues. The compartmentation of hyperaccumulated foliar Mn appears exceptional among metal hyperaccumulators, since it occurs via specific microdistribution patterns. Here, three associated Mn hyperaccumulators, Virotia neurophylla, Maytenus fournieri, and Garcinia amplexicaulis exhibiting distinctly different Mn detoxification strategies were examined. Non-invasive sample preparation in conjunction with cryo scanning electron microscopy (SEM) was used to obtain in vivo quantitative microprobe X-ray and anatomical data from fully hydrated cells. Highly vacuolated large palisade mesophyll cells in V. neurophylla leaves were found to contain around 650mM Mn. The large non-photosynthetic hypodermal cells of M. fournieri leaves, also with high vacuolar content, and the main site for Mn disposal, had an estimated mean vacuolar Mn concentration of around 600mM. Previous qualitative X-ray mapping had shown Mn to be almost evenly sequestered across the entire leaf cross section of G. amplexicaulis. However, quantitative data obtained here showed a marked variation in localised concentrations that ranged between~15 and>800mM. Notable among these were mean values of>600mM in spongy mesophyll cells, and~800mM within cells of a narrow sub epidermal layer preceding the palisade mesophyll. This study demonstrated the extraordinary Mn carrying capacities of different types of leaf cell vacuoles. PMID:22772585

  19. 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...

  20. Selenium hyperaccumulation offers protection from cell disruptor herbivores.

    TOXLINE Toxicology Bibliographic Information

    Quinn CF; Freeman JL; Reynolds RJ; Cappa JJ; Fakra SC; Marcus MA; Lindblom SD; Quinn EK; Bennett LE; Pilon-Smits EA

    2010-01-01

    BACKGROUND: Hyperaccumulation, the rare capacity of certain plant species to accumulate toxic trace elements to levels several orders of magnitude higher than other species growing on the same site, is thought to be an elemental defense mechanism against herbivores 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 periphery, making them potentially more susceptible to some herbivore feeding modes than others. In this study we investigate the protective function of Se in the Se hyperaccumulators Stanleya pinnata and Astragalus bisulcatus against two cell disrupting herbivores, the western flower thrips (Frankliniella occidentalis) and the two-spotted spider mite (Tetranychus urticae).RESULTS: Astragalus bisulcatus and S. pinnata with high Se concentrations (greater than 650 mg Se kg(-1)) were less subject to thrips herbivory than plants with low Se levels (less than 150 mg Se kg(-1)). Furthermore, in plants containing elevated Se levels, leaves with higher concentrations of Se suffered less herbivory than leaves with less Se. Spider mites also preferred to feed on low-Se A. bisulcatus and S. pinnata plants rather than high-Se plants. Spider mite populations on A. bisulcatus decreased after plants were given a higher concentration of Se. Interestingly, spider mites could colonize A. bisulcatus plants containing up to 200 mg Se kg(-1) dry weight, concentrations which are toxic to many other herbivores. Selenium distribution and speciation studies using micro-focused X-ray fluorescence (?XRF) mapping and Se K-edge X-ray absorption spectroscopy revealed that the spider mites accumulated primarily methylselenocysteine, the relatively non-toxic form of Se that is also the predominant form of Se in hyperaccumulators.CONCLUSIONS: This is the first reported study investigating the protective effect of hyperaccumulated Se against cell-disrupting herbivores. The finding that Se protected the two hyperaccumulator species from both cell disruptors lends further support to the elemental defense hypothesis and increases the number of herbivores and feeding modes against which Se has shown a protective effect. Because western flower thrips and two-spotted spider mites are widespread and economically important herbivores, the results from this study also have potential applications in agriculture or horticulture, and implications for the management of Se-rich crops.

  1. Selenium hyperaccumulation offers protection from cell disruptor herbivores

    PubMed Central

    2010-01-01

    Background Hyperaccumulation, the rare capacity of certain plant species to accumulate toxic trace elements to levels several orders of magnitude higher than other species growing on the same site, is thought to be an elemental defense mechanism against herbivores 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 periphery, making them potentially more susceptible to some herbivore feeding modes than others. In this study we investigate the protective function of Se in the Se hyperaccumulators Stanleya pinnata and Astragalus bisulcatus against two cell disrupting herbivores, the western flower thrips (Frankliniella occidentalis) and the two-spotted spider mite (Tetranychus urticae). Results Astragalus bisulcatus and S. pinnata with high Se concentrations (greater than 650 mg Se kg-1) were less subject to thrips herbivory than plants with low Se levels (less than 150 mg Se kg-1). Furthermore, in plants containing elevated Se levels, leaves with higher concentrations of Se suffered less herbivory than leaves with less Se. Spider mites also preferred to feed on low-Se A. bisulcatus and S. pinnata plants rather than high-Se plants. Spider mite populations on A. bisulcatus decreased after plants were given a higher concentration of Se. Interestingly, spider mites could colonize A. bisulcatus plants containing up to 200 mg Se kg-1 dry weight, concentrations which are toxic to many other herbivores. Selenium distribution and speciation studies using micro-focused X-ray fluorescence (μXRF) mapping and Se K-edge X-ray absorption spectroscopy revealed that the spider mites accumulated primarily methylselenocysteine, the relatively non-toxic form of Se that is also the predominant form of Se in hyperaccumulators. Conclusions This is the first reported study investigating the protective effect of hyperaccumulated Se against cell-disrupting herbivores. The finding that Se protected the two hyperaccumulator species from both cell disruptors lends further support to the elemental defense hypothesis and increases the number of herbivores and feeding modes against which Se has shown a protective effect. Because western flower thrips and two-spotted spider mites are widespread and economically important herbivores, the results from this study also have potential applications in agriculture or horticulture, and implications for the management of Se-rich crops. PMID:20799959

  2. 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.

  3. Arsenic speciation, and arsenic and phosphate distribution in arsenic hyperaccumulator Pteris vittata L. and non-hyperaccumulator Pteris ensiformis L.

    PubMed

    Singh, Nandita; Ma, Lena Q

    2006-05-01

    This study 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 Brake fern), a non-arsenic hyperaccumulator. After growing in 20% Hoagland solution containing 0, 133 or 267 microM of sodium arsenate for 1, 5 or 10 d, the plants were separated into fronds, rhizomes, and roots. They were analyzed for biomass, and concentrations of arsenate (AsV), arsenite (AsIII) and phosphorus. Arsenic in the fronds of P. vittata was up to 20 times greater than that of P. ensiformis, yet showing no toxicity symptoms as did in P. ensiformis. While arsenic was concentrated primarily in the fronds of P. vittata as arsenite it was mainly concentrated in the roots of P. ensiformis as arsenate. Arsenic reduction in the plants took longer than 1-d. P. vittata maintained greater P in the roots while P. ensiformis in the fronds. The high arsenic tolerance of the hyperaccumulator P. vittata may be attributed to its ability to effectively reduce arsenate to arsenite in the fronds, translocate arsenic from the roots to fronds, and maintain a greater ratio of P/As in the roots. PMID:16257102

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

    PubMed

    DeTar, Rachael Ann; Alford, lan 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

  5. Effects of cold-pressing and seed cooking on functional properties of protein in pennycress (Thlaspi arvense L.) seed and press cakes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current interest in pennycress (Thlaspi arvense L.) comes from its seed oil, which is being evaluated for biofuel production. The seed also has notable protein content (27% moisture-free, oil-free basis). The effects of oil processing conditions on functionality of pennycress seed proteins were dete...

  6. 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

  7. 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

  8. 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.

  9. Nopalea cochenillifera, a potential chromium (VI) hyperaccumulator plant.

    PubMed

    Adki, Vinayak S; Jadhav, Jyoti P; Bapat, Vishwas A

    2013-02-01

    Hexavalant chromium [Cr(VI)] tolerance and accumulation in in vitro grown Nopalea cochenillifera Salm. Dyck. plants was investigated. A micropropagation protocol was establish for a rapid multiplication of N. cochenillifera and [Cr(VI)] tolerance and accumulation was studied in in vitro grown cultures. Cr concentration was estimated by atomic absorption spectroscopy in roots and shoots to confirm plant's hyperaccumulation capacity. Plants showed tolerance up to 100 μM K(2)Cr(2)O(7) without any significant changes in root growth after 16 days treatment; whereas, chlorophyll content in plants treated with 1 and 10 μM K(2)Cr(2)O(7) were not so different than the control plant. The levels of lipid peroxidation and protein oxidation increased significantly (p < 0.01) with increasing concentration of chromium. Exposures of N. cochenillifera to lower concentrations of K(2)Cr(2)O(7) (≤ 10 μM) induced catalase (CAT) and superoxide dismutase (SOD) significantly (p < 0.001) but higher concentrations of K(2)Cr(2)O(7) (>100 μM) inhibited the activities of CAT and SOD. Roots accumulated a maximum of 25,263.396 ± 1,722.672 mg Cr Kg(-1) dry weight (DW); while the highest concentration of Cr in N. cochenillifera shoots was 705.714 ± 32.324 mg Cr Kg(-1) DW. N. cochenillifera could be a prospective hyperaccumulator plant of Cr(VI) and a promising candidate for phytoremediation purposes. PMID:22914913

  10. 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

  11. Prosopis pubescens (screw bean mesquite) seedlings are hyperaccumulators of copper.

    PubMed

    Zappala, Marian N; Ellzey, Joanne T; Bader, Julia; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge

    2013-08-01

    Due to health reasons, toxic metals must be removed from soils contaminated by mine tailings and smelter activities. The phytoremediation potential of Prosopis pubescens (screw bean mesquite) was examined by use of inductively-coupled plasma optical emission spectroscopy. Transmission electron microscopy was used to observe ultrastructural changes of parenchymal cells of leaves in the presence of copper. Elemental analysis was used to localize copper within leaves. A 600-ppm copper sulfate exposure to seedlings for 24 days resulted in 31,000 ppm copper in roots, 17,000 ppm in stems, 11,000 in cotyledons and 20 ppm in the true leaves. For a plant to be considered a hyperaccumulator, the plant must accumulate a leaf-to-root ratio <1. Screw bean mesquite exposed to copper had a leaf-to-root ratio of 0.355 when cotyledons were included. We showed that P. pubescens grown in soil is a hyperaccumulator of copper. We recommend that this plant should be field tested. PMID:23612918

  12. A newly found manganese hyperaccumulator-Polygonum lapathifolium Linn.

    PubMed

    Liu, Kehui; Yu, Fangming; Chen, Menglin; Zhou, Zhenming; Chen, Chaoshu; Li, Ming Shun; Zhu, Jing

    2016-04-01

    In the present work, both field investigation and laboratory experiment were carried out to testify whether Polygonum lapathifolium L. is a potential manganese (Mn) hyperaccumulator. Results from field investigation showed that P. lapathifolium had great tolerance and accumulation to Mn. Mn concentrations in leaves were the highest, varied from 6889.2 mg kg-1 dry weight (DW) to18841.7 mg kg(-1) DW with the average of 12180.6 mg kg(-1). The values of translocation factor (the concentrations of Mn in leaf to that in root) ranged from 5.72 to 9.53. Results from laboratory experiment illuminated that P. lapathifolium could grow well and show no toxic symptoms even under high Mn stress (16 mmol L(-1)). Although the changes of antioxidant enzymes activities were triggered under Mn stress, the alterations of pigments were not significant (P > 0.05) as compared with control. Total plant biomass and plant height increased with increasing Mn supply. Mn concentrations in leaves and stems were constantly greater than those in roots, the ratio of concentrations in leaves to that in roots were 2.58-6.72 and the corresponding values in stems to that in roots were 1.45-3.18. The results showed that P. lapathifolium is a Mn-hyperaccumulator. PMID:26514228

  13. The role of phytochelatins in constitutive and adaptive heavy metal tolerances in hyperaccumulator and non-hyperaccumulator metallophytes.

    PubMed

    Schat, Henk; Llugany, Merc; Vooijs, Riet; Hartley-Whitaker, Jeanette; Bleeker, Petra M

    2002-12-01

    Using the gamma-glutamylcysteine synthetase inhibitor, L-buthionine-[S,R]-sulphoximine (BSO), the role for phytochelatins (PCs) was evaluated in Cu, Cd, Zn, As, Ni, and Co tolerance in non-metallicolous and metallicolous, hypertolerant populations of Silene vulgaris (Moench) Garcke, Thlaspi caerulescens J.&C. Presl., Holcus lanatus L., and Agrostis castellana Boiss. et Reuter. Based on plant-internal PC-thiol to metal molar ratios, the metals' tendency to induce PC accumulation decreased in the order As/Cd/Cu > Zn > Ni/Co, and was consistently higher in non-metallicolous plants than in hypertolerant ones, except for the case of As. The sensitivities to Cu, Zn, Ni, and Co were consistently unaffected by BSO treatment, both in non-metallicolous and hypertolerant plants, suggesting that PC-based sequestration is not essential for constitutive tolerance or hypertolerance to these metals. Cd sensitivity was considerably increased by BSO, though exclusively in plants lacking Cd hypertolerance, suggesting that adaptive cadmium hypertolerance is not dependent on PC-mediated sequestration. BSO dramatically increased As sensitivity, both in non-adapted and As-hypertolerant plants, showing that PC-based sequestration is essential for both normal constitutive tolerance and adaptive hypertolerance to this metalloid. The primary function of PC synthase in plants and algae remains elusive. PMID:12432030

  14. Sulfur-selenium-molybdenum interactions distinguish selenium hyperaccumulator Stanleya pinnata from non-hyperaccumulator Brassica juncea (Brassicaceae).

    PubMed

    Harris, Jonathan; Schneberg, Kathryn A; Pilon-Smits, Elizabeth A H

    2014-02-01

    Long-term sulfate, selenate and molybdate accumulation and translocation were investigated in two ecotypes of Stanleya pinnata and non-hyperaccumulator Brassica juncea under different levels of applied sulfate and selenate. Morphological differences were observed between the ecotypes of S. pinnata, but few differences in selenium (Se) and sulfur (S) accumulation were measured. Se-to-S ratios were nearly identical between the ecotypes under all treatments. When compared with B. juncea, several unique trends were observed in the hyperaccumulators. While both S. pinnata ecotypes showed no significant effect on Se content of young leaves when the supplied sulfate in the growth medium was increased tenfold (from 0.5 to 5 mM), the Se levels in B. juncea decreased 4- to 12-fold with increased sulfate in the growth medium. Furthermore, S. pinnatas S levels decreased slightly with high levels of supplied Se, suggesting competitive inhibition of uptake, while B. juncea showed higher S levels with increasing Se, possibly due to up-regulation of sulfate transporters. Both ecotypes of S. pinnata showed much larger Se concentrations in young leaves, while B. juncea showed slightly higher levels of Se in older leaves relative to young. Molybdenum (Mo) levels significantly decreased in S. pinnata with increasing sulfate and selenate in the medium; B. juncea did not show the same trends. These findings support the hypothesis that S. pinnata contains a modified sulfate transporter with a higher specificity for selenate. PMID:24233101

  15. 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.

  16. Microbeam methodologies as powerful tools in manganese hyperaccumulation research: present status and future directions

    PubMed Central

    Fernando, Denise R.; Marshall, Alan; Baker, Alan J. M.; Mizuno, Takafumi

    2013-01-01

    Microbeam studies over the past decade have garnered unique insight into manganese (Mn) homeostasis in plant species that hyperaccumulate this essential mineral micronutrient. Electron- and/or proton-probe methodologies employed to examine tissue elemental distributions have proven highly effective in illuminating excess foliar Mn disposal strategies, some apparently unique to Mn hyperaccumulating plants. When applied to samples prepared with minimal artefacts, these are powerful tools for extracting true snapshot data of living systems. For a range of reasons, Mn hyperaccumulation is particularly suited to in vivo interrogation by this approach. Whilst microbeam investigation of metallophytes is well documented, certain methods originally intended for non-biological samples are now widely applied in biology. This review examines current knowledge about Mn hyperaccumulators with reference to microbeam methodologies, and discusses implications for future research into metal transporters. PMID:23970891

  17. 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

  18. Heavy metal tolerance in metal hyperaccumulator plant, Salvinia natans.

    PubMed

    Dhir, B; Srivastava, S

    2013-06-01

    Metal tolerance capacity of Salvinia natans, a metal hyperaccumulator, was evaluated. Plants were exposed to 10, 30 and 50 mg L? of Zn, Cd, Co, Cr, Fe, Cu, Pb, and Ni. Plant biomass, photosynthetic efficiency, quantum yield, photochemical quenching, electron transport rate and elemental (%C, H and N) constitution remained unaffected in Salvinia exposed to 30 mg L? of heavy metals, except for Cu and Zn exposed plants, where significant reductions were noted in some of the measured parameters. However, a significant decline was noted in most of the measured parameters in plants exposed to 50 mg L? of metal concentration. Results suggest that Salvinia has fairly high levels of tolerance to all the metals tested, but the level of tolerance varied from metal to metal. PMID:23553503

  19. Mechanisms of efficient arsenite uptake by arsenic hyperaccumulator Pteris vittata.

    PubMed

    Wang, Xin; Ma, Lena Q; Rathinasabapathi, Bala; Cai, Yong; Liu, Yun Guo; Zeng, Guang Ming

    2011-11-15

    Arsenate (AsV) and arsenite (AsIII) are two dominant arsenic species in the environment. While arsenate uptake is via phosphate transporter in plants, including arsenic hyperaccumulator Pteris vittata , AsIII uptake mechanisms by P. vittata are unclear. In this study, we investigated AsIII uptake by P. vittata involving root radial transport from external medium to cortical cells and xylem loading. In the root symplastic solution, AsIII was the predominant species (90-94%) and its concentrations were 1.6-21 times those in the medium. AsIII influx into root symplast followed Michaelis-Menten kinetics with K(m) of 77.7 ?M at external AsIII concentrations of 2.6-650 ?M. In the presence of metabolic inhibitor 2,4-dinitrophenol (DNP), arsenic concentrations in the root symplast were reduced to the levels lower than in the medium, indicating that a transporter-mediated active process was mainly responsible for AsIII influx into P. vittata roots. Unlike radial transport, AsIII loading into xylem involved both high- and low-affinity systems with K(m) of 8.8 ?M and 70.4 ?M, respectively. As indicated by the effect of 2,4-DNP, passive diffusion became more important in arsenic loading into xylem at higher external AsIII. The unique AsIII uptake system in P. vittata makes it a valuable model to understand the mechanisms of arsenic hyperaccumulation in the plant kingdom. PMID:22029254

  20. Analysis of selenium accumulation, speciation and tolerance of potential selenium hyperaccumulator Symphyotrichum ericoides.

    PubMed

    El Mehdawi, Ali F; Reynolds, Ray Jason B; Prins, Christine N; Lindblom, Stormy D; Cappa, Jennifer J; Fakra, Sirine C; Pilon-Smits, Elizabeth A H

    2014-09-01

    Symphyotrichum ericoides was shown earlier to contain hyperaccumulator levels of selenium (Se) in the field (>1000 mg kg(-1) dry weight (DW)), but only when growing next to other Se hyperaccumulators. It was also twofold larger next to hyperaccumulators and suffered less herbivory. This raised two questions: whether S. ericoides is capable of hyperaccumulation without neighbor assistance, and whether its Se-derived benefit is merely ecological or also physiological. Here, in a comparative greenhouse study, Se accumulation and tolerance of S. ericoides were analyzed in parallel with hyperaccumulator Astragalus bisulcatus, Se accumulator Brassica juncea and related Asteraceae Machaeranthera tanacetifolia. Symphyotrichum ericoides and M. tanacetifolia accumulated Se up to 3000 and 1500 mg Se kg(-1) DW, respectively. They were completely tolerant to these Se levels and even grew 1.5- to 2.5-fold larger with Se. Symphyotrichum ericoides showed very high leaf Se/sulfur (S) and shoot/root Se concentration ratios, similar to A. bisulcatus and higher than M. tanacetifolia and B. juncea. Se X-ray absorption near-edge structure spectroscopy showed that S. ericoides accumulated Se predominantly (86%) as C-Se-C compounds indistinguishable from methyl-selenocysteine, which may explain its Se tolerance. Machaeranthera tanacetifolia accumulated 55% of its Se as C-Se-C compounds; the remainder was inorganic Se. Thus, in this greenhouse study S. ericoides displayed all of the characteristics of a hyperaccumulator. The larger size of S. ericoides when growing next to hyperaccumulators may be explained by a physiological benefit, in addition to the ecological benefit demonstrated earlier. PMID:24423113

  1. 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...

  2. Transient Influx of Nickel in Root Mitochondria Modulates Organic Acid and Reactive Oxygen Species Production in Nickel Hyperaccumulator Alyssum murale*

    PubMed Central

    Agrawal, Bhavana; Czymmek, Kirk J.; Sparks, Donald L.; Bais, Harsh P.

    2013-01-01

    Mitochondria are important targets of metal toxicity and are also vital for maintaining metal homeostasis. Here, we examined the potential role of mitochondria in homeostasis of nickel in the roots of nickel hyperaccumulator plant Alyssum murale. We evaluated the biochemical basis of nickel tolerance by comparing the role of mitochondria in closely related nickel hyperaccumulator A. murale and non-accumulator Alyssum montanum. Evidence is presented for the rapid and transient influx of nickel in root mitochondria of nickel hyperaccumulator A. murale. In an early response to nickel treatment, substantial nickel influx was observed in mitochondria prior to sequestration in vacuoles in the roots of hyperaccumulator A. murale compared with non-accumulator A. montanum. In addition, the mitochondrial Krebs cycle was modulated to increase synthesis of malic acid and citric acid involvement in nickel hyperaccumulation. Furthermore, malic acid, which is reported to form a complex with nickel in hyperaccumulators, was also found to reduce the reactive oxygen species generation induced by nickel. We propose that the interaction of nickel with mitochondria is imperative in the early steps of nickel uptake in nickel hyperaccumulator plants. Initial uptake of nickel in roots results in biochemical responses in the root mitochondria indicating its vital role in homeostasis of nickel ions in hyperaccumulation. PMID:23322782

  3. Using Chelator-Buffered Nutrient Solutions to Induce Ni-Deficiency in the Ni-Hyperaccumulator Alyssum murale

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ni is essential for all plants due to its role in urease. Many Alyssum species are known to hyperaccumulate Ni to over 20 g kg-1 dry weight (DW) while normal plants require only about 0.1 mg kg-1 DW. As part of our research on Ni hyperaccumulation by plants, we conducted experiments to measure the...

  4. 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...

  5. Recent advances in the analysis of metal hyperaccumulation and hypertolerance in plants using proteomics

    PubMed Central

    DalCorso, Giovanni; Fasani, Elisa; Furini, Antonella

    2013-01-01

    Hyperaccumulator/hypertolerant plant species have evolved strategies allowing them to grow in metal-contaminated soils, where they accumulate high concentrations of heavy metals in their shoots without signs of toxicity. The mechanisms that allow enhanced metal uptake, root-to-shoot translocation and detoxification in these species are not fully understood. Complementary approaches such as transcriptomic-based DNA microarrays and proteomics have recently been used to gain insight into the molecular pathways evolved by metal hyperaccumulator/hypertolerant species. Proteomics has the advantage of focusing on the translated portion of the genome and it allows to analyze complex networks of proteins. This review discusses the recent analysis of metal hyperaccumulator/hypertolerant plant species using proteomics. Changes in photosynthetic proteins, sulfur, and glutathione metabolism, transport, biotic and xenobiotic defenses as well as the differential regulation of proteins involved in signaling and secondary metabolism are discussed in relation to metal hyperaccumulation. We also consider the potential contribution of several proteins to the hyperaccumulation phenotype. PMID:23898342

  6. 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

  7. 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

  8. 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

  9. 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.

  10. 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.

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

    PubMed

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

    2015-04-01

    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 crystal structure of the thiocyanate-forming protein from Thlaspi arvense, a kelch protein involved in glucosinolate breakdown.

    PubMed

    Gumz, Frauke; Krausze, Joern; Eisenschmidt, Daniela; Backenkhler, Anita; Barleben, Leif; Brandt, Wolfgang; Wittstock, Ute

    2015-09-01

    Kelch repeat-containing proteins are involved in diverse cellular processes, but only a small subset of plant kelch proteins has been functionally characterized. Thiocyanate-forming protein (TFP) from field-penny cress, Thlaspi arvense (Brassicaceae), is a representative of specifier proteins, a group of kelch proteins involved in plant specialized metabolism. As components of the glucosinolate-myrosinase system of the Brassicaceae, specifier proteins determine the profile of bioactive products formed when plant tissue is disrupted and glucosinolates are hydrolyzed by myrosinases. Here, we describe the crystal structure of TaTFP at a resolution of 1.4 . TaTFP crystallized as homodimer. Each monomer forms a six-blade ?-propeller with a wide "top" and a narrower "bottom" opening with distinct strand-connecting loops protruding far beyond the lower propeller surface. Molecular modeling and mutational analysis identified residues for glucosinolate aglucone and Fe(2+) cofactor binding within these loops. As the first experimentally determined structure of a plant kelch protein, the crystal structure of TaTFP not only enables more detailed mechanistic studies on glucosinolate breakdown product formation, but also provides a new basis for research on the diverse roles and mechanisms of other kelch proteins in plants. PMID:26260516

  13. The effect of nitrogen form on rhizosphere soil pH and zinc phytoextraction by Thlaspi caerulescens.

    PubMed

    Monsant, A C; Tang, C; Baker, A J M

    2008-10-01

    The phytoextraction of Zn may be improved by applying N fertilizers to increase the biomass and Zn content of shoots. Rhizosphere-pH change from uptake of different N forms will affect Zn phyto-availability in the rhizosphere and Zn phytoextraction. This glasshouse study examined the effect of N form on Zn phytoextraction by Thlaspi caerulescens (Prayon). The plants were grown in a Zn-contaminated soil (total Zn 250 mg kg-1 soil; pHwater 5.7) and supplied with (NH4)2SO4, Ca(NO3)2 or urea [(NH2)2CO]. The form was maintained by applying the nitrification inhibitor dicyandiamide. A biodegradable chelator ethylenediaminedisuccinic acid (EDDS) was included for comparison. The addition of N doubled the shoot biomass. The highest shoot Zn content occurred in the Ca(NO3)2 treatment and was associated with the highest rhizosphere pH. The lowest shoot dry weight occurred in the EDDS treatment. The Zn concentration in the shoots increased as the rhizosphere pH increased. A significant correlation occurred between Ca and Zn concentrations in the shoots. This study demonstrated that Ca(NO3)2 is a more effective treatment than , urea or EDDS for enhancing Zn phytoextraction in a mildly acidic soil. PMID:18752830

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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...

  19. PROGRESS REPORT. MOLECULAR DISSECTION OF THE CELLULAR MECHANISMS INVOLVED IN NICKEL HYPERACCUMULATION

    EPA Science Inventory

    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 advanta...

  20. FINAL REPORT. MOLECULAR DISSECTION OF THE CELLULAR MECHANISMS INVOLVED IN NICKEL HYPERACCUMULATION

    EPA Science Inventory

    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 advanta...

  1. 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...

  2. The metal hyperaccumulators from New Caledonia can broaden our understanding of nickel accumulation in plants.

    PubMed

    Jaffr, Tanguy; Pillon, Yohan; Thomine, Sbastien; Merlot, Sylvain

    2013-01-01

    While an excess of metals such as zinc, cadmium or nickel (Ni) is toxic for most plants, about 500 plant species called hyperaccumulators are able to accumulate high amounts of these metals. These plants and the underlying mechanisms are receiving an increasing interest because of their potential use in sustainable biotechnologies such as biofortification, phytoremediation, and phytomining. Among hyperaccumulators, about 400 species scattered in 40 families accumulate Ni. Despite this wide diversity, our current knowledge of the mechanisms involved in Ni accumulation is still limited and mostly restricted to temperate herbaceous Brassicaceae. New Caledonia is an archipelago of the tropical southwest pacific with a third of its surface (5500 km(2)) covered by Ni-rich soils originating from ultramafic rocks. The rich New Caledonia flora contains 2145 species adapted to these soils, among which 65 are Ni hyperaccumulators, including lianas, shrubs or trees, mostly belonging to the orders Celastrales, Oxalidales, Malpighiales, and Gentianales. We present here our current knowledge on Ni hyperaccumulators from New Caledonia and the latest molecular studies developed to better understand the mechanisms of Ni accumulation in these plants. PMID:23898341

  3. 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

  4. Transcriptomic analysis of cadmium stress response in the heavy metal hyperaccumulator Sedum alfredii Hance.

    PubMed

    Gao, Jun; Sun, Ling; Yang, Xiaoe; Liu, Jian-Xiang

    2014-01-01

    The Sedum alfredii Hance hyperaccumulating ecotype (HE) has the ability to hyperaccumulate cadmium (Cd), as well as zinc (Zn) and lead (Pb) in above-ground tissues. Although many physiological studies have been conducted with these plants, the molecular mechanisms underlying their hyper-tolerance to heavy metals are largely unknown. Here we report on the generation of 9.4 gigabases of adaptor-trimmed raw sequences and the assembly of 57,162 transcript contigs in S. alfredii Hance (HE) shoots by the combination of Roche 454 and Illumina/Solexa deep sequencing technologies. We also have functionally annotated the transcriptome and analyzed the transcriptome changes upon Cd hyperaccumulation in S. alfredii Hance (HE) shoots. There are 110 contigs and 123 contigs that were up-regulated (Fold Change ? 2.0) and down-regulated (Fold Change hyperaccumulating ecotype (NHE). Our results demonstrated that several genes involved in cell wall modification, metal translocation and remobilization were more induced or constitutively expressed at higher levels in HE shoots than that in NHE shoots in response to Cd exposure. Together, our study provides large-scale expressed sequence information and genome-wide transcriptome profiling of Cd responses in S. alfredii Hance (HE) shoots. PMID:23755133

  5. Transcriptomic Analysis of Cadmium Stress Response in the Heavy Metal Hyperaccumulator Sedum alfredii Hance

    PubMed Central

    Yang, Xiaoe; Liu, Jian-Xiang

    2013-01-01

    The Sedum alfredii Hance hyperaccumulating ecotype (HE) has the ability to hyperaccumulate cadmium (Cd), as well as zinc (Zn) and lead (Pb) in above-ground tissues. Although many physiological studies have been conducted with these plants, the molecular mechanisms underlying their hyper-tolerance to heavy metals are largely unknown. Here we report on the generation of 9.4 gigabases of adaptor-trimmed raw sequences and the assembly of 57,162 transcript contigs in S. alfredii Hance (HE) shoots by the combination of Roche 454 and Illumina/Solexa deep sequencing technologies. We also have functionally annotated the transcriptome and analyzed the transcriptome changes upon Cd hyperaccumulation in S. alfredii Hance (HE) shoots. There are 110 contigs and 123 contigs that were up-regulated (Fold Change ≧2.0) and down-regulated (Fold Change ≦0.5) by chronic Cd treatment in S. alfredii Hance (HE) at q-value cutoff of 0.005, respectively. Quantitative RT-PCR was employed to compare gene expression patterns between S. alfredii Hance (HE) and non-hyperaccumulating ecotype (NHE). Our results demonstrated that several genes involved in cell wall modification, metal translocation and remobilization were more induced or constitutively expressed at higher levels in HE shoots than that in NHE shoots in response to Cd exposure. Together, our study provides large-scale expressed sequence information and genome-wide transcriptome profiling of Cd responses in S. alfredii Hance (HE) shoots. PMID:23755133

  6. Uncoupling of reactive oxygen species accumulation and defence signalling in the metal hyperaccumulator plant Noccaea caerulescens.

    PubMed

    Fones, Helen N; Eyles, Chris J; Bennett, Mark H; Smith, J Andrew C; Preston, Gail M

    2013-09-01

    The metal hyperaccumulator plant Noccaea caerulescens is protected from disease by the accumulation of high concentrations of metals in its aerial tissues, which are toxic to many pathogens. As these metals can lead to the production of damaging reactive oxygen species (ROS), metal hyperaccumulator plants have developed highly effective ROS tolerance mechanisms, which might quench ROS-based signals. We therefore investigated whether metal accumulation alters defence signalling via ROS in this plant. We studied the effect of zinc (Zn) accumulation by N.caerulescens on pathogen-induced ROS production, salicylic acid accumulation and downstream defence responses, such as callose deposition and pathogenesis-related (PR) gene expression, to the bacterial pathogen Pseudomonas syringae pv. maculicola. The accumulation of Zn caused increased superoxide production in N.caerulescens, but inoculation with P.syringae did not elicit the defensive oxidative burst typical of most plants. Defences dependent on signalling through ROS (callose and PR gene expression) were also modified or absent in N.caerulescens, whereas salicylic acid production in response to infection was retained. These observations suggest that metal hyperaccumulation is incompatible with defence signalling through ROS and that, as metal hyperaccumulation became effective as a form of elemental defence, normal defence responses became progressively uncoupled from ROS signalling in N.caerulescens. PMID:23758201

  7. Organic acids rather than histidine predominate in Ni chelation in Alyssum hyperaccumulator xylem exudate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A better understanding of Ni uptake mechanisms by hyperaccumulator plants is necessary to improve Ni uptake efficiency for phytoremediation technologies i.e. phytomining. It is known that an important aspect of Ni translocation involves Ni chelation with organic ligands. However, it is still not cle...

  8. The metal hyperaccumulators from New Caledonia can broaden our understanding of nickel accumulation in plants

    PubMed Central

    Jaffr, Tanguy; Pillon, Yohan; Thomine, Sbastien; Merlot, Sylvain

    2013-01-01

    While an excess of metals such as zinc, cadmium or nickel (Ni) is toxic for most plants, about 500 plant species called hyperaccumulators are able to accumulate high amounts of these metals. These plants and the underlying mechanisms are receiving an increasing interest because of their potential use in sustainable biotechnologies such as biofortification, phytoremediation, and phytomining. Among hyperaccumulators, about 400 species scattered in 40 families accumulate Ni. Despite this wide diversity, our current knowledge of the mechanisms involved in Ni accumulation is still limited and mostly restricted to temperate herbaceous Brassicaceae. New Caledonia is an archipelago of the tropical southwest pacific with a third of its surface (5500 km2) covered by Ni-rich soils originating from ultramafic rocks. The rich New Caledonia flora contains 2145 species adapted to these soils, among which 65 are Ni hyperaccumulators, including lianas, shrubs or trees, mostly belonging to the orders Celastrales, Oxalidales, Malpighiales, and Gentianales. We present here our current knowledge on Ni hyperaccumulators from New Caledonia and the latest molecular studies developed to better understand the mechanisms of Ni accumulation in these plants. PMID:23898341

  9. High-throughput fluorescence-activated cell sorting for lipid hyperaccumulating Chlamydomonas reinhardtii mutants.

    PubMed

    Xie, Bo; Stessman, Dan; Hart, Jason H; Dong, Haili; Wang, Yingjun; Wright, David A; Nikolau, Basil J; Spalding, Martin H; Halverson, Larry J

    2014-09-01

    The genetically tractable microalga Chlamydomonas reinhardtii has many advantages as a model for renewable bioproducts and/or biofuels production. However, one limitation of C.reinhardtii is its relatively low-lipid content compared with some other algal species. To overcome this limitation, we combined ethane methyl sulfonate mutagenesis with fluorescence-activated cell sorting (FACS) of cells stained with the lipophilic stain Nile Red to isolate lipid hyperaccumulating mutants of C.reinhardtii. By manipulating the FACS gates, we sorted mutagenized cells with extremely high Nile Red fluorescence signals that were rarely detected in nonmutagenized populations. This strategy successfully isolated several putative lipid hyperaccumulating mutants exhibiting 23% to 58% (dry weight basis) higher fatty acid contents than their progenitor strains. Significantly, for most mutants, nitrogen starvation was not required to attain high-lipid content nor was there a requirement for a deficiency in starch accumulation. Microscopy of Nile Red stained cells revealed that some mutants exhibit an increase in the number of lipid bodies, which correlated with TLC analysis of triacyglycerol content. Increased lipid content could also arise through increased biomass production. Collectively, our findings highlight the ability to enhance intracellular lipid accumulation in algae using random mutagenesis in conjunction with a robust FACS and lipid yield verification regime. Our lipid hyperaccumulating mutants could serve as a genetic resource for stacking additional desirable traits to further increase lipid production and for identifying genes contributing to lipid hyperaccumulation, without lengthy lipid-induction periods. PMID:24702864

  10. SPECTROMICROSCOPIC INVESTIGATION OF CO SPECIATION IN A NI/CO HYPERACCUMULATOR PLANT USED FOR PHYTOREMEDIATION AND PHYTOMINING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metal contamination of surface and subsurface environments is a worldwide concern. Unique metallophyte plants (hyperaccumulators) accumulate high concentrations of trace metals in their harvestable biomass, and thereby offer a sustainable method for treatment of metal-contaminated sites (phytoremed...

  11. 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

  12. 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

  13. Rinorea niccolifera (Violaceae), a new, nickel-hyperaccumulating species from Luzon Island, Philippines

    PubMed Central

    Fernando, Edwino S.; Quimado, Marilyn O.; Doronila, Augustine I.

    2014-01-01

    Abstract A new, nickel-hyperaccumulating species of Rinorea (Violaceae), Rinorea niccolifera Fernando, from Luzon Island, Philippines, is described and illustrated. This species is most similar to the widespread Rinorea bengalensis by its fasciculate inflorescences and smooth subglobose fruits with 3 seeds, but it differs by its glabrous ovary with shorter style (5 mm long), the summit of the staminal tube sinuate to entire and the outer surface smooth, generally smaller leaves (3–8 cm long × 2–3 cm wide), and smaller fruits (0.6–0.8 cm diameter). Rinorea niccolifera accumulates to >18,000 µg g-1 of nickel in its leaf tissues and is thus regarded as a Ni hyperaccumulator. PMID:24843295

  14. 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

  15. 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

  16. Application of rhizosphere interaction of hyperaccumulator Noccaea caerulescens to remediate cadmium-contaminated agricultural soil.

    PubMed

    Yang, Yong; Jiang, Rong-Feng; Wang, Wei; Li, Hua-Fen

    2011-10-01

    There is an urgent requirement for selecting appropriate technologies to solve food safety problems due to soil contamination. In this study, the hyperaccumulator Noccaea caerulescens and a high Cd accumulator pakchoi cultivar (Brassica rapa L. spp. Chinenesis cv.) were grown in a moderately Cd-contaminated soil with three planting systems (monocrop, inter-crop, and crop-rotation) and three growing durations (25, 50, and 75 days) to study the role of rhizosphere interaction of both species on the uptake of Cd. The Cd accumulations in the shoot of pakchoi were significantly reduced in the inter-crop treatment, also the decreased percentage increased with rhizosphere interaction between the two species. In the inter-crop systems of 75 days, the Cd concentration and amount in the shoot of pakchoi represented 54% and 83% reduction, respectively, while the total depletion of Cd decreased by approximate 19%. Although the Cd concentration and amount in the shoot of pakchoi were significantly reduced by 52% and 44%, respectively, in the crop-rotation treatment, the decreased percentage were markedly lower than in the inter-crop treatment. Therefore, the rhizosphere interaction of hyperaccumulator with non-hyperaccumulator may reduce the risk of vegetable contamination during making full use of or remediating the contaminated soil. PMID:21972514

  17. 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

  18. Root and shoot transcriptome analysis of two ecotypes of Noccaea caerulescens uncovers the role of NcNramp1 in Cd hyperaccumulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Zn/Cd hyperaccumulator, Noccaea caerulescens, has been studied extensively for its ability to accumulate Zn and Cd in its leaves to extremely high levels. Previous studies have indicated that the Zn and Cd hyperaccumulation trait exhibited by this species involves different transport and toleran...

  19. Synergistic effects of arbuscular mycorrhizal fungi and phosphate rock on heavy metal uptake and accumulation by an arsenic hyperaccumulator.

    PubMed

    Leung, H M; Wu, F Y; Cheung, K C; Ye, Z H; Wong, M H

    2010-09-15

    The effects of arbuscular mycorrhizal (AM) fungi and phosphate rock on the phytorextraction efficiency of a hyperaccumulator (Pteris vittata) and a non-hyperaccumulator (Cynodon dactylon) plant were studied. Both seedlings were planted in As contaminated soil under different treatments [(1) control (contaminated soil only), (2) indigenous mycorrhizas (IM), (3) mixed AM inoculum [indigenous mycorrhiza + Glomus mosseae (IM/Gm)] and (4) IM/Gm + phosphate rock (P rock)] with varying intensities (40%, 70% and 100%) of water moisture content (WMC). Significant As reduction in soil (23.8% of soil As reduction), increase in plant biomass (17.8 g/pot) and As accumulation (2054 mg/kg DW) were observed for P. vittata treated with IM/Gm + PR at 100% WMC level. The overall results indicated that the synergistic effect of mycorrhiza and P rock affected As subcellular distribution of the hyperaccumulator and thereby altered its As removal efficiency under well-watered conditions. PMID:20541316

  20. 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

  1. 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

  2. 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

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

    PubMed Central

    Freeman, John L.; Tamaoki, Masanori; Stushnoff, Cecil; Quinn, Colin F.; Cappa, Jennifer J.; Devonshire, Jean; Fakra, Sirine C.; Marcus, Matthew A.; McGrath, Steve P.; Van Hoewyk, Doug; Pilon-Smits, Elizabeth A.H.

    2010-01-01

    The molecular mechanisms responsible for selenium (Se) tolerance and hyperaccumulation were studied in the Se hyperaccumulator Stanleya pinnata (Brassicaceae) by comparing it with the related secondary Se accumulator Stanleya albescens using a combination of physiological, structural, genomic, and biochemical approaches. S. pinnata accumulated 3.6-fold more Se and was tolerant to 20 μm selenate, while S. albescens suffered reduced growth, chlorosis and necrosis, impaired photosynthesis, and high levels of reactive oxygen species. Levels of ascorbic acid, glutathione, total sulfur, and nonprotein thiols were higher in S. pinnata, suggesting that Se tolerance may in part be due to increased antioxidants and up-regulated sulfur assimilation. S. pinnata had higher selenocysteine methyltransferase protein levels and, judged from liquid chromatography-mass spectrometry, mainly accumulated the free amino acid methylselenocysteine, while S. albescens accumulated mainly the free amino acid selenocystathionine. S. albescens leaf x-ray absorption near-edge structure scans mainly detected a carbon-Se-carbon compound (presumably selenocystathionine) in addition to some selenocysteine and selenate. Thus, S. albescens may accumulate more toxic forms of Se in its leaves than S. pinnata. The species also showed different leaf Se sequestration patterns: while S. albescens showed a diffuse pattern, S. pinnata sequestered Se in localized epidermal cell clusters along leaf margins and tips, concentrated inside of epidermal cells. Transcript analyses of S. pinnata showed a constitutively higher expression of genes involved in sulfur assimilation, antioxidant activities, defense, and response to (methyl)jasmonic acid, salicylic acid, or ethylene. The levels of some of these hormones were constitutively elevated in S. pinnata compared with S. albescens, and leaf Se accumulation was slightly enhanced in both species when these hormones were supplied. Thus, defense-related phytohormones may play an important signaling role in the Se hyperaccumulation of S. pinnata, perhaps by constitutively up-regulating sulfur/Se assimilation followed by methylation of selenocysteine and the targeted sequestration of methylselenocysteine. PMID:20498337

  4. 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

  5. Rhizosphere microbial densities and trace metal tolerance of the nickel hyperaccumulator Alyssum serpyllifolium subsp. lusitanicum.

    PubMed

    Becerra-Castro, C; Monterroso, C; Garca-Lestn, M; Prieto-Fernndez, A; Acea, M J; Kidd, P S

    2009-08-01

    In this study we determine culturable microbial densities (total heterotrophs, ammonifiers, amylolytics and cellulolytics) and bacterial resistance to Co, Cr, and Ni in bulk and rhizosphere soils of three populations of the Ni-hyperaccumulator Alyssum serpyllifolium subsp. lusitanicum and the excluder Dactylis glomerata from ultramafic sites (two populations in Northeast (NE) Portugal (Samil (S), Morais (M)) and one population in Northwest (NW) Spain (Melide (L)). The relationship between bioavailable metal concentrations (H2O-soluble) and microbial densities were analysed. Significant differences in microbial densities and metal-resistance were observed between the two species and their three populations. The hyperaccumulator showed higher microbial densities (except cellulolytics) and a greater rhizosphere effect, but this was only observed in S and M populations. These populations of A. serpyllifolium also showed selective enrichment of Ni-tolerant bacteria at the rhizosphere where Ni solubility was enhanced (densities of Ni-resistant bacteria were positively correlated with H2O-soluble Ni). These rhizobacteria could solubilise Ni in the soil and potentially improve phytoextraction strategies. PMID:19810353

  6. Extreme nickel hyperaccumulation in the vascular tracts of the tree Phyllanthus balgooyi from Borneo.

    PubMed

    Mesjasz-Przybylowicz, Jolanta; Przybylowicz, Wojciech; Barnabas, Alban; van der Ent, Antony

    2016-03-01

    Phyllanthus balgooyi (Phyllanthaceae), one of > 20 nickel (Ni) hyperaccumulator plant species known in Sabah (Malaysia) on the island of Borneo, is remarkable because it contains > 16 wt% Ni in its phloem sap, the second highest concentration of Ni in any living material in the world (after Pycnandra acuminata (Sapotaceae) from New Caledonia with 25 wt% Ni in latex). This study focused on the tissue-level distribution of Ni and other elements in the leaves, petioles and stem of P. balgooyi using nuclear microprobe imaging (micro-PIXE). The results show that in the stems and petioles of P. balgooyi Ni concentrations were very high in the phloem, while in the leaves there was significant enrichment of this element in the major vascular bundles. In the leaves, cobalt (Co) was codistributed with Ni, while the distribution of manganese (Mn) was different. The highest enrichment of calcium (Ca) in the stems was in the periderm, the epidermis and subepidermis of the petiole, and in the palisade mesophyll of the leaf. Preferential accumulation of Ni in the vascular tracts suggests that Ni is present in a metabolically active form. The elemental distribution of P. balgooyi differs from those of many other Ni hyperaccumulator plant species from around the world where Ni is preferentially accumulated in leaf epidermal cells. PMID:26508435

  7. Organic amendments for improving biomass production and metal yield of Ni-hyperaccumulating plants.

    PubMed

    Álvarez-López, V; Prieto-Fernández, Á; Cabello-Conejo, M I; Kidd, P S

    2016-04-01

    Ni phytomining is a promising technology for Ni recovery from low-grade ores such as ultramafic soils. Metal-hyperaccumulators are good candidates for phytomining due to their extraordinary capacity for Ni accumulation. However, many of these plants produce a low biomass, which makes the use of agronomic techniques for improving their growth necessary. In this study, the Ni hyperaccumulators Alyssum serpyllifolium ssp. lusitanicum, A. serpyllifolium ssp. malacitanum, Alyssum bertolonii and Noccaea goesingense were evaluated for their Ni phytoextraction efficiency from a Ni-rich serpentine soil. Effects of soil inorganic fertilisation (100:100:125kgNPKha(-1)) and soil organic amendment addition (2.5, 5 or 10% compost) on plant growth and Ni accumulation were determined. All soil treatments greatly improved plant growth, but the highest biomass production was generally found after addition of 2.5 or 5% compost (w/w). The most pronounced beneficial effects were observed for N. goesingense. Total Ni phytoextracted from soils was significantly improved using both soil treatments (inorganic and organic), despite the decrease observed in soil Ni availability and shoot Ni concentrations in compost-amended soils. The most promising results were found using intermediate amount of compost, indicating that these types of organic wastes can be incorporated into phytomining systems. PMID:26803735

  8. 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.

  9. 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

  10. Arsenic complexes in the arsenic hyperaccumulator Pteris vittata (Chinese brake fern).

    PubMed

    Zhang, Weihua; Cai, Yong; Downum, Kelsey R; Ma, Lena Q

    2004-07-23

    Pteris vittata (Chinese brake fern), the first reported arsenic (As) hyperaccumulating plant, can be potentially applied in the phytoremediation As-contaminated sites. Understanding the mechanisms of As tolerance and detoxification in this plant is critical to further enhance its capability of As hyperaccumulation. In this study, an unknown As species, other than arsenite (AsIII) or arsenate (AsV) was found in leaflets by using anion-exchange chromatography-hydride generation-atomic fluorescence spectroscopy and size-exclusion chromatography-atomic fluorescence spectrometry. The chromatographic behavior of this unknown As species and its stability suggest that it is likely an As complex. Although phytochelatin with two subunits (PC2) was the only major thiol in P. vittata under As exposure, this unknown As complex was unlikely to be an AsIII-PC2 complex by comparison of their chromatographic behaviors, stability at different pHs and charge states. The complex is sensitive to temperature and metal ions, but relatively insensitive to pH. In buffer solution of pH 5.9, it is present in a neutral form. PMID:15330099

  11. 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

  12. Screening of a new cadmium hyperaccumulator, Galinsoga parviflora, from winter farmland weeds using the artificially high soil cadmium concentration method.

    PubMed

    Lin, Lijin; Jin, Qian; Liu, Yingjie; Ning, Bo; Liao, Ming'an; Luo, Li

    2014-11-01

    A new method, the artificially high soil cadmium (Cd) concentration method, was used to screen for Cd hyperaccumulators among winter farmland weeds. Galinsoga parviflora was the most promising remedial plant among 5 Cd accumulators or hyperaccumulators. In Cd concentration gradient experiments, as soil Cd concentration increased, root and shoot biomass decreased, and their Cd contents increased. In additional concentration gradient experiments, superoxide dismutase and peroxidase activities increased with soil Cd concentrations up to 75?mg?kg(-1) , while expression of their isoenzymes strengthened. Catalase (CAT) activity declined and CAT isoenzyme expression weakened at soil Cd concentrations less than 50?mg?kg(-1) . The maxima of Cd contents in shoots and roots were 137.63?mg?kg(-1) and 105.70?mg?kg(-1) , respectively, at 100?mg?kg(-1) Cd in soil. The root and shoot bioconcentration factors exceeded 1.0, as did the translocation factor. In a field experiment, total extraction of Cd by shoots was 1.35?mg?m(-2) to 1.43?mg?m(-2) at soil Cd levels of 2.04?mg?kg(-1) to 2.89?mg?kg(-1) . Therefore, the artificially high soil Cd concentration method was effective for screening Cd hyperaccumulators. Galinsoga parviflora is a Cd hyperaccumulator that could be used to efficiently remediate Cd-contaminated farmland soil. PMID:25053512

  13. 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...

  14. 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...

  15. 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...

  16. 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 didnt reach the standard, species mentioned above were primarily believed to be potential hyperaccumulators.

  17. 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...

  18. 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...

  19. 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...

  20. 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.

  1. 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

  2. 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

  3. Selenium uptake by edible oyster mushrooms (Pleurotus sp.) from selenium-hyperaccumulated wheat straw.

    PubMed

    Bhatia, Poonam; Prakash, Ranjana; Prakash, N Tejo

    2013-01-01

    In an effort to produce selenium (Se)-fortifying edible mushrooms, five species of oyster mushroom (Pleurotus sp.), were cultivated on Se-rich wheat straw collected from a seleniferous belt of Punjab, India. Total selenium was analyzed in the selenium hyperaccumulated wheat straw and the fruiting bodies. Significantly high levels (p<0.0001) of Se uptake were observed in fruiting bodies of all mushrooms grown on Se-rich wheat straw. To the best of our knowledge, accumulation and quantification of selenium in mushrooms has hitherto not been reported with substrates naturally enriched with selenium. The results demonstrate the potential of selenium-rich agricultural residues as substrates for production of Se-enriched mushrooms and the ability of different species of oyster mushrooms to absorb and fortify selenium. The study envisages potential use of selenium-rich agricultural residues towards cultivation of Se-enriched mushrooms for application in selenium supplementation or neutraceutical preparations. PMID:23535542

  4. 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

  5. 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.

  6. Nickel localization on tissues of hyperaccumulator species of phyllanthus L. (Euphorbiaceae) from ultramafic areas of Cuba.

    PubMed

    Berazan, R; de la Fuente, V; Snchez-Mata, D; Rufo, L; Rodrguez, N; Amils, R

    2007-01-01

    Two species of perennial Phyllanthus (Euphorbiaceae) (Phyllanthus orbicularis and Phyllanthus discolor, both endemic to ultramafic areas of Cuba, and their natural hybrid, Phyllanthus xpallidus) were selected for metal localization microanalysis. Different plant tissues were analyzed by X-ray fluorescence, inductively coupled plasma-atomic emission spectroscopy, and scanning electron microscopy coupled with an energy-dispersive X-ray probe. All of the studied taxa are nickel (Ni) hyperaccumulators and significant concentrations of this element were found in different leaf and stem tissues. The highest Ni content was found in the laticifer tubes, whereas leaf epidermis Ni content resulted to be much more relevant in terms of total metal storage. Calcium and magnesium were found more evenly distributed in leaf and stem tissues. PMID:17406075

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

    PubMed

    Moradi, Ahmad B; Conesa, Hctor 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

  8. Phytoremediation of uranium-contaminated soils: Role of organic acids in triggering uranium hyperaccumulation in plants

    SciTech Connect

    Huang, J.W.; Blaylock, M.J.; Kapulnik, Y.; Ensley, B.D.

    1998-07-01

    Uranium phytoextraction, the use of plants to extract U from contaminated soils, is an emerging technology. The authors report on the development of this technology for the cleanup of U-contaminated soils. In this research, they investigated the effects of various soil amendments on U desorption from soil to soil solution, studied the physiological characteristics of U uptake and accumulation in plants, and developed techniques to trigger U hyperaccumulation in plants. A key to the success of U phytoextraction is to increase soil U availability to plants. The authors have found that some organic acids can be added to soils to increase U desorption from soil to soil solution and to trigger a rapid U accumulation in plants. Of the organic acids (acetic acid, citric acid, and malic acid) tested, citric acid was the most effective in enhancing U accumulation in plants. Shoot U concentrations of Brassica juncea and Brassica chinensis grown in a U-contaminated soil increased from less than 5 mg kg{sup {minus}1} to more than 5,000 mg kg{sup {minus}1} in citric acid-treated soils. To their knowledge, this is the highest shoot U concentration reported for plants grown on U-contaminated soils. Using this U hyperaccumulation technique, they are now able to increase U accumulation in shoots of selected plant species grown in two U-contaminated soils by more than 1,000-fold within a few days. The results suggest that U phytoextraction may provide an environmentally friendly alternative for the cleanup of U-contaminated soils.

  9. Influence of nitrogen form on the phytoextraction of cadmium by a newly discovered hyperaccumulator Carpobrotus rossii.

    PubMed

    Liu, Wuxing; Zhang, Chengjun; Hu, Pengjie; Luo, Yongming; Wu, Longhua; Sale, Peter; Tang, Caixian

    2016-01-01

    Using hyperaccumulator plants is an important method to remove heavy metals from contaminated land. Carpobrotus rossii, a newly found Cd hyperaccumulator, has shown potential to remediate Cd-contaminated soils. This study examined the effect of nitrogen forms on Cd phytoextraction by C. rossii. The plants were grown for 78days in an acid soil spiked with 20mgCdkg(-1) and supplied with (NH4)2SO4, Ca(NO3)2, urea, and chicken manure as nitrogen (N) fertilizers. Nitrification inhibitor dicyandiamide (DCD) was applied to maintain the ammonium (NH4 (+)) form. Nitrogen fertilization increased shoot biomass but decreased root biomass with the highest shoot biomass occurring in the manure treatment. Compared to the no-N control, urea application did not affect shoot Cd concentration, but increased Cd content by 17% due to shoot biomass increase. Chicken manure significantly decreased CaCl2-extractable Cd in soil, and the Cd concentration and total Cd uptake in the plant. Rhizosphere pH was the highest in the manure treatment and the lowest in the NH4 (+) treatments. The manure and nitrate (NO3 (-)) treatments tended to have higher rhizosphere pH than their respective bulk soil pH, whereas the opposite was observed for urea and NH4 (+) treatments. Furthermore, the concentrations of extractable Cd in soil and Cd in the plant correlated negatively with rhizosphere pH. The study concludes that urea significantly enhanced the Cd phytoaccumulation by C. rossii while chicken manure decreased Cd availability in soil and thus the phytoextraction efficiency. PMID:26358206

  10. 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

  11. 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

  12. Characterization of Zinc and Cadmium Hyperaccumulation in Three Noccaea (Brassicaceae) Populations from Non-metalliferous Sites in the Eastern Pyrenees

    PubMed Central

    Martos, Soledad; Gallego, Berta; Sáez, Llorenç; López-Alvarado, Javier; Cabot, Catalina; Poschenrieder, Charlotte

    2016-01-01

    The Southern slope of the Pyrenees is the meridional limit for the distribution of several Noccaea populations. However, the systematic description of these populations and their hyperaccumulation mechanisms are not well established. Morphological and genetic analysis (ITS and 3 chloroplast regions) were used to identify Noccaea populations localized on non-metallicolous soils during a survey in the Catalonian Pyrenees. Cd and Zn concentrations were analyzed in soils and plants both sampled in the field and grown hydroponically. The expression of selected metal transporter genes was assessed by quantitative PCR. The populations were identified as Noccaea brachypetala (Jord.) F.K. Mey by conspicuous morphological traits. Principal component analysis provided a clear separation among N. brachypetala, Noccaea caerulescens J. Presl & C. Presl and Noccaea occitanica (Jord.) F.K. Mey., three Noccaea species reported in the Pyrenees. Contrastingly, ITS and cpDNA analyses were unable to clearly differentiate these taxa. Differences in the expression of the metal transporter genes HMA3, HMA4, and MTP1 between N. caerulescens and N. brachypetala, and those amongst the N. brachypetala populations suggest differences in the strategies for handling enhanced Cd and Zn availability. This is the first report demonstrating Cd and Zn hyperaccumulation by N. brachypetala both in the field and in hydroponics. This comprehensive study based on taxonomic, molecular, and physiological data allows both the correct identification of this species and the characterization of population differences in hyperaccumulation and tolerance of Zn and Cd. PMID:26904085

  13. Characterization of Zinc and Cadmium Hyperaccumulation in Three Noccaea (Brassicaceae) Populations from Non-metalliferous Sites in the Eastern Pyrenees.

    PubMed

    Martos, Soledad; Gallego, Berta; Sáez, Llorenç; López-Alvarado, Javier; Cabot, Catalina; Poschenrieder, Charlotte

    2016-01-01

    The Southern slope of the Pyrenees is the meridional limit for the distribution of several Noccaea populations. However, the systematic description of these populations and their hyperaccumulation mechanisms are not well established. Morphological and genetic analysis (ITS and 3 chloroplast regions) were used to identify Noccaea populations localized on non-metallicolous soils during a survey in the Catalonian Pyrenees. Cd and Zn concentrations were analyzed in soils and plants both sampled in the field and grown hydroponically. The expression of selected metal transporter genes was assessed by quantitative PCR. The populations were identified as Noccaea brachypetala (Jord.) F.K. Mey by conspicuous morphological traits. Principal component analysis provided a clear separation among N. brachypetala, Noccaea caerulescens J. Presl & C. Presl and Noccaea occitanica (Jord.) F.K. Mey., three Noccaea species reported in the Pyrenees. Contrastingly, ITS and cpDNA analyses were unable to clearly differentiate these taxa. Differences in the expression of the metal transporter genes HMA3, HMA4, and MTP1 between N. caerulescens and N. brachypetala, and those amongst the N. brachypetala populations suggest differences in the strategies for handling enhanced Cd and Zn availability. This is the first report demonstrating Cd and Zn hyperaccumulation by N. brachypetala both in the field and in hydroponics. This comprehensive study based on taxonomic, molecular, and physiological data allows both the correct identification of this species and the characterization of population differences in hyperaccumulation and tolerance of Zn and Cd. PMID:26904085

  14. 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.

  15. 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 M 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

  16. The variation of root exudates from the hyperaccumulator Sedum alfredii under cadmium stress: metabonomics analysis.

    PubMed

    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 M 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

  17. Bacteria-mediated arsenic oxidation and reduction in the growth media of arsenic hyperaccumulator Pteris vittata.

    PubMed

    Wang, Xin; Rathinasabapathi, Bala; de Oliveira, Letuzia Maria; Guilherme, Luiz R G; Ma, Lena Q

    2012-10-16

    Microbes play an important role in arsenic transformation and cycling in the environment. Microbial arsenic oxidation and reduction were demonstrated in the growth media of arsenic hyperaccumulator Pteris vittata L. All arsenite (AsIII) at 0.1 mM in the media was oxidized after 48 h incubation. Oxidation was largely inhibited by antibiotics, indicating that bacteria played a dominant role. To identify AsIII oxidizing bacteria, degenerate primers were used to amplify ?500 bp of the AsIII oxidase gene aioA (aroA) using DNA extracted from the media. One aioA (aroA)-like sequence (MG-1, tentatively identified as Acinetobacter sp.) was amplified, exhibiting 82% and 91% identity in terms of gene and deduced protein sequence to those from Acinetobacter sp. 33. In addition, four bacterial strains with different arsenic tolerance were isolated and identified as Comamonas sp.C-1, Flavobacterium sp. C-2, Staphylococcus sp. C-3, and Pseudomonas sp. C-4 using carbon utilization, fatty acid profiles, and/or sequencing 16s rRNA gene. These isolates exhibited dual capacity for both AsV reduction and AsIII oxidation under ambient conditions. Arsenic-resistant bacteria with strong AsIII oxidizing ability may have potential to improve bioremediation of AsIII-contaminated water using P. vittata and/or other biochemical strategies. PMID:22994133

  18. Arsenic enhanced plant growth and altered rhizosphere characteristics of hyperaccumulator Pteris vittata.

    PubMed

    Xu, Jia Yi; Li, Hong Bo; Liang, Shuang; Luo, Jun; Ma, Lena Q

    2014-11-01

    We investigated the effects of arsenic species on As accumulation, plant growth and rhizospheric changes in As-hyperaccumulator Pteris vittata (PV). PV was grown for 60-d in a soil spiked with 200mgkg(-1) arsenate (AsV-soil) or arsenite (AsIII-soil). Diffusive gradients in thin-films technique (DGT) were used to monitor As uptake by PV. Interestingly AsIII-soil produced the highest PV biomass at 8.6gplant(-1), 27% and 46% greater than AsV-soil and the control. Biomass increase was associated with As-induced P uptake by PV. Although AsIII was oxidized to AsV during the experiment, As species impacted As accumulation by PV, with 17.5% more As in AsIII-soil than AsV-soil (36 vs. 31mgplant(-1)). As concentration in PV roots was 30% higher in AsV-soil whereas As concentration in PV fronds was 7.9% greater in AsIII-soil, suggesting more rapid translocation of AsIII than AsV. These findings were important to understand the mechanisms of As uptake, accumulation and translocation by PV. PMID:25103044

  19. Evaluation of novel starch-deficient mutants of Chlorella sorokiniana for hyper-accumulation of lipids

    PubMed Central

    Vonlanthen, Sofie; Dauvillée, David; Purton, Saul

    2015-01-01

    When green algae are exposed to physiological stresses such as nutrient deprivation, growth is arrested and the cells channel fixed carbon instead into storage compounds, accumulating first starch granules and then lipid bodies containing triacylglycerides. In recent years there has been significant interest in the commercial exploitation of algal lipids as a sustainable source of biodiesel. Since starch and lipid biosynthesis involves the same C3 precursor pool, it has been proposed that mutations blocking starch accumulation should result in increased lipid yields, and indeed several studies have supported this. The fast-growing, thermotolerant alga Chlorella sorokiniana represents an attractive strain for industrial cultivation. We have therefore generated and characterized starch-deficient mutants of C. sorokiniana and determined whether lipid levels are increased in these strains under stress conditions. One mutant (ST68) is shown to lack isoamylase, whilst two others (ST3 and ST12) are defective in starch phosphorylase. However, we find no significant change in the accumulation or profile of fatty acids in these mutants compared to the wild-type, suggesting that a failure to accumulate starch per se is not sufficient for the hyper-accumulation of lipid, and that more subtle regulatory steps underlie the partitioning of carbon to the two storage products. PMID:26865991

  20. Effects of grafting on the cadmium accumulation characteristics of the potential Cd-hyperaccumulator Solanum photeinocarpum.

    PubMed

    Lin, Lijin; Yang, Daiyu; Wang, Xun; Liao, Ming'an; Wang, Zhihui; Lv, Xiulan; Tang, Fuyi; Liang, Dong; Xia, Hui; Lai, Yunsong; Tang, Yi

    2016-02-01

    The effects of grafting on the cadmium (Cd) accumulation characteristics of the potential Cd-hyperaccumulator Solanum photeinocarpum were studied under Cd stress in our experiment. Four treatments were used in the experiment: ungrafted (UG), self-rooted grafting by the same S. photeinocarpum seedling (SG), self-rooted grafting by two different development stages of S. photeinocarpum seedlings (DG), and grafting on the rootstock of wild potato (PG). SG and DG decreased the root, scion stem, leaf, whole shoot, and whole plant biomasses compared with UG, but increased the rootstock stem biomass, while only PG increased the root and whole plant biomasses. SG and DG increased the Cd contents in the different organs of S. photeinocarpum compared with UG, while PG decreased the Cd content compared with UG. The Cd extraction by the whole plant of S. photeinocarpum was ranked as DG?>?SG?>?UG?>?PG. Additionally, the antioxidant enzyme activities in SG and DG were enhanced compared with UG, while that of PG was reduced compared with UG. The grafting increased the DNA methylation levels and changed the methylation patterns of S. photeinocarpum compared with UG. Therefore, SG and DG can increase the Cd accumulation in S. photeinocarpum, which can be used for the phytoremediation of Cd-contaminated soil. PMID:26739012

  1. 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?L?L(-1)) or elevated (800?L?L(-1)) CO2 . Elevated CO2 significantly (P?

  2. 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

  3. 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 500M arsenate (AsV) for 28d. 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 10M AsV, but high AsIII efflux (36-76%) was observed at 200 and 500M AsV, with 1987-2397mgkg(-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

  4. Accumulation and distribution characteristics of zinc and cadmium in the hyperaccumulator plant Sedum plumbizincicola.

    PubMed

    Cao, Dong; Zhang, Hongzheng; Wang, Yaodong; Zheng, Leina

    2014-08-01

    Accumulation and distribution of Zn and Cd in the hyperaccumulator plant Sedum plumbizincicola were investigated in a hydroponic experiment. Mean Cd and Zn concentrations in shoots (7,010 and 18,400 mg kg(-1)) were about sevenfold and fivefold higher than those in roots (840 and 3,000 mg kg(-1)) after exposure to 100 ?M CdSO4 and 600 ?M ZnSO4, respectively. Cd and Zn concentrations in young leaves (4,330 and 9,820 mg kg(-1)) were about sixfold and twofold higher than those in mature leaves (636 and 2,620 mg kg(-1)), respectively. MicroPIXE analysis showed that Zn was predominantly localized in epidermal cells in both young and mature leaves, but large amounts of Zn occurred in mesophyll cells in young leaves. Leaf tissue fractionation showed that soluble and cell wall fractions were different at the two stages of leaf growth. Young and mature leaves of S. plumbizincicola also showed different accumulation and distribution characteristics for Zn and Cd. PMID:24789526

  5. 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

  6. Lewis acid catalysis and Green oxidations: sequential tandem oxidation processes induced by Mn-hyperaccumulating plants.

    PubMed

    Escande, Vincent; Renard, Brice-Loc; Grison, Claude

    2015-04-01

    Among the phytotechnologies used for the reclamation of degraded mining sites, phytoextraction aims to diminish the concentration of polluting elements in contaminated soils. However, the biomass resulting from the phytoextraction processes (highly enriched in polluting elements) is too often considered as a problematic waste. The manganese-enriched biomass derived from native Mn-hyperaccumulating plants of New Caledonia was presented here as a valuable source of metallic elements of high interest in chemical catalysis. The preparation of the catalyst Eco-Mn1 and reagent Eco-Mn2 derived from Grevillea exul exul and Grevillea exul rubiginosa was investigated. Their unusual polymetallic compositions allowed to explore new reactivity of low oxidative state of manganese-Mn(II) for Eco-Mn1 and Mn(IV) for Eco-Mn2. Eco-Mn1 was used as a Lewis acid to catalyze the acetalization/elimination of aldehydes into enol ethers with high yields; a new green and stereoselective synthesis of (-)-isopulegol via the carbonyl-ene cyclization of (+)-citronellal was also performed with Eco-Mn1. Eco-Mn2 was used as a mild oxidative reagent and controlled the oxidation of aliphatic alcohols into aldehydes with quantitative yields. Oxidative cleavage was interestingly noticed when Eco-Mn2 was used in the presence of a polyol. Eco-Mn2 allowed direct oxidative iodination of ketones without using iodine, which is strongly discouraged by new environmental legislations. Finally, the combination of the properties in the Eco-Mn catalysts and reagents gave them an unprecedented potential to perform sequential tandem oxidation processes through new green syntheses of p-cymene from (-)-isopulegol and (+)-citronellal; and a new green synthesis of functionalized pyridines by in situ oxidation of 1,4-dihydropyridines. PMID:25263417

  7. Daclatasvir inhibits hepatitis C virus NS5A motility and hyper-accumulation of phosphoinositides

    PubMed Central

    Chukkapalli, Vineela; Berger, Kristi L.; Kelly, Sean M.; Thomas, Meryl; Deiters, Alexander; Randall, Glenn

    2014-01-01

    Combinations of direct-acting antivirals (DAAs) against the hepatitis C virus (HCV) have the potential to revolutionize the HCV therapeutic regime. An integral component of DAA combination therapies are HCV NS5A inhibitors. It has previously been proposed that NS5A DAAs inhibit two functions of NS5A: RNA replication and virion assembly. In this study, we characterize the impact of a prototype NS5A DAA, daclatasvir (DCV), on HCV replication compartment formation. DCV impaired HCV replicase localization and NS5A motility. In order to characterize the mechanism behind altered HCV replicase localization, we examined the impact of DCV on the interaction of NS5A with its essential cellular cofactor, phosphatidylinositol-4-kinase III ? (PI4KA). We observed that DCV does not inhibit PI4KA directly, nor does it impair early events of the NS5A-PI4KA interaction that can occur when NS5A is expressed alone. NS5A functions that are unaffected by DCV include PI4KA binding, as determined by co-immunoprecipitation, and a basal accumulation of the PI4KA product, PI4P. However, DCV impairs late steps in PI4KA activation that requires NS5A expressed in the context of the HCV polyprotein. These NS5A functions include hyper-stimulation of PI4P levels and appropriate replication compartment formation. The data are most consistent with a model wherein DCV inhibits conformational changes in the NS5A protein or protein complex formations that occur in the context of HCV polyprotein expression and stimulate PI4P hyper-accumulation and replication compartment formation. PMID:25546252

  8. 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 CrVI₀.₁₀, and 5100 and 3500 mg/kg P in the fronds and roots at P₀.₂₅. 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, Cr₂O₃ 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

  9. Characterization of three distinct metallothionein genes of the Ag-hyperaccumulating ectomycorrhizal fungus Amanita strobiliformis.

    PubMed

    Hlokov, Kate?ina; Mat?nov, Michaela; ?kov, Petra; Strnad, Hynek; Hrelov, Hana; Hroudov, Milue; Kotrba, Pavel

    2016-03-01

    Mechanisms evolved in eukaryotes to handle heavy metals involve cytosolic, metal-binding metallothioneins (MTs). We have previously documented that the sequestration of silver (Ag) in the Ag-hyperaccumulating Amanita strobiliformis is dominated by 34-amino-acid (AA) AsMT1a, 1b, and 1c isoforms. Here we show that in addition to AsMT1a, 1b, and 1c isogenes, the fungus has two other MT genes: AsMT2 encoding a 34-AA AsMT2 similar to MTs known from other species, but unrelated to AsMT1s; AsMT3 coding for a 62-AA AsMT3 that shares substantial identity with as-yet-uncharacterized conserved peptides predicted in agaricomycetes. Transcription of AsMT1s and AsMT3 in the A. strobiliformis mycelium was specifically inducible by treatments with Ag or copper (Cu) and zinc (Zn) or cadmium (Cd), respectively; AsMT2 showed a moderate upregulation in the presence of Cd. Expression of AsMTs in the metal-sensitive Saccharomyces cerevisiae revealed that all AsMTs confer increased Cd tolerance (AsMT3 proved the most effective) and that, unlike AsMT1 and AsMT2, AsMT3 can protect the yeasts against Zn toxicity. The highest level of Cu tolerance was observed with yeasts expressing AsMT1a. Our data indicate that A. strobiliformis can specifically employ different MT genes for functions in the cellular handling of Ag and Cu (AsMT1s) and Zn (AsMT3). PMID:26895864

  10. 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

  11. Characterization of a selenium-tolerant rhizosphere strain from a novel Se-hyperaccumulating plant Cardamine hupingshanesis.

    PubMed

    Tong, Xinzhao; 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

  12. 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

  13. Micro-PIXE as a technique for studying nickel localization in leaves of the hyperaccumulator plant Alyssum lesbiacum

    NASA Astrophysics Data System (ADS)

    Krmer, U.; Grime, G. W.; Smith, J. A. C.; Hawes, C. R.; Baker, A. J. M.

    1997-07-01

    Certain terrestrial plants are able to accumulate metals such as zinc, manganese, nickel, cobalt, or copper in their above-ground biomass. The largest group of these so-called "metal hyperaccumulators" is to be found among certain species in the family Brassicaceae endemic to ultramafic soils. For example, nickel concentrations in members of the genus Alyssum can reach 3% of the leaf dry biomass. However, nickel levels in the root tissue of these plants are low, suggesting that hyperaccumulation is associated with effective metal translocation from root to shoot and sequestration of the metal in non-toxic form within the leaves. To investigate the sites of nickel localization within A. lesbiacum, leaf cross-sections were examined by nuclear microscopy using PIXE and RBS on the Oxford Scanning Proton Microprobe (SPM) with a spatial resolution of 1 ?m. This paper describes the sample preparation and analysis methods and presents some preliminary results indicating that nickel is sequestered to a considerable degree within the epidermal trichomes on the leaf surface.

  14. Complexation with dissolved organic matter and mobility control of heavy metals in the rhizosphere of hyperaccumulator Sedum alfredii.

    PubMed

    Li, Tingqiang; Tao, Qi; Liang, Chengfeng; Shohag, M J I; Yang, Xiaoe; Sparks, Donald L

    2013-11-01

    The complexation of Zn, Cd and Pb with dissolved organic matter (DOM) in the rhizosphere of hyperaccumulating ecotype (HE) and a non-hyperaccumulating ecotype (NHE) of Sedum alfredii was measured using resin equilibration method. After the growth of HE S. alfredii, the rhizosphere soil pH was reduced by 0.27-0.33 units, due to enhanced DOM derived from root exudation. For both ecotypes of S. alfredii, the fraction of free metal as a percentage of soluble metal varied from 22.1 to 42.5% for Zn(2+), from 8.1 to 15.5% for Cd(2+), and from 4.5 to 10.4% for Pb(2+). Resin equilibration experiment results indicated that HE-DOM had greater ability to form complexes with Zn, Cd and Pb than NHE-DOM, Visual MINTEQ model gave excellent predictions of the complexation of Zn and Cd by DOM (R(2) > 0.97). DOM in the rhizosphere of HE S. alfredii could significantly increase metal mobility through the formation of soluble DOM-metal complexes. PMID:23938448

  15. 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

  16. Tonoplast- and Plasma Membrane-Localized Aquaporin-Family Transporters in Blue Hydrangea Sepals of Aluminum Hyperaccumulating Plant

    PubMed Central

    Negishi, Takashi; Oshima, Kenshiro; Hattori, Masahira; Kanai, Masatake; Mano, Shoji; Nishimura, Mikio; Yoshida, Kumi

    2012-01-01

    Hydrangea (Hydrangea macrophylla) is tolerant of acidic soils in which toxicity generally arises from the presence of the soluble aluminum (Al) ion. When hydrangea is cultivated in acidic soil, its resulting blue sepal color is caused by the Al complex formation of anthocyanin. The concentration of vacuolar Al in blue sepal cells can reach levels in excess of approximately 15 mM, suggesting the existence of an Al-transport and/or storage system. However, until now, no Al transporter has been identified in Al hyperaccumulating plants, animals or microorganisms. To identify the transporter being responsible for Al hyperaccumulation, we prepared a cDNA library from blue sepals according to the sepal maturation stage, and then selected candidate genes using a microarray analysis and an in silico study. Here, we identified the vacuolar and plasma membrane-localized Al transporters genes vacuolar Al transporter (VALT) and plasma membrane Al transporter 1 (PALT1), respectively, which are both members of the aquaporin family. The localization of each protein was confirmed by the transient co-expression of the genes. Reverse transcription-PCR and immunoblotting results indicated that VALT and PALT1 are highly expressed in sepal tissue. The overexpression of VALT and PALT1 in Arabidopsis thaliana conferred Al-tolerance and Al-sensitivity, respectively. PMID:22952644

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

    PubMed

    Rees, Frdric; 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

  18. Tonoplast- and plasma membrane-localized aquaporin-family transporters in blue hydrangea sepals of aluminum hyperaccumulating plant.

    PubMed

    Negishi, Takashi; Oshima, Kenshiro; Hattori, Masahira; Kanai, Masatake; Mano, Shoji; Nishimura, Mikio; Yoshida, Kumi

    2012-01-01

    Hydrangea (Hydrangea macrophylla) is tolerant of acidic soils in which toxicity generally arises from the presence of the soluble aluminum (Al) ion. When hydrangea is cultivated in acidic soil, its resulting blue sepal color is caused by the Al complex formation of anthocyanin. The concentration of vacuolar Al in blue sepal cells can reach levels in excess of approximately 15 mM, suggesting the existence of an Al-transport and/or storage system. However, until now, no Al transporter has been identified in Al hyperaccumulating plants, animals or microorganisms. To identify the transporter being responsible for Al hyperaccumulation, we prepared a cDNA library from blue sepals according to the sepal maturation stage, and then selected candidate genes using a microarray analysis and an in silico study. Here, we identified the vacuolar and plasma membrane-localized Al transporters genes vacuolar Al transporter (VALT) and plasma membrane Al transporter 1 (PALT1), respectively, which are both members of the aquaporin family. The localization of each protein was confirmed by the transient co-expression of the genes. Reverse transcription-PCR and immunoblotting results indicated that VALT and PALT1 are highly expressed in sepal tissue. The overexpression of VALT and PALT1 in Arabidopsis thaliana conferred Al-tolerance and Al-sensitivity, respectively. PMID:22952644

  19. Sulfate and chromate increased each other's uptake and translocation in As-hyperaccumulator Pteris vittata.

    PubMed

    de Oliveira, Letúzia M; Gress, Julia; De, Jaysankar; Rathinasabapathi, Bala; Marchi, Giuliano; Chen, Yanshan; Ma, Lena Q

    2016-03-01

    We investigated the effects of chromate (CrVI) and sulfate on their uptake and translocation in As-hyperaccumulator Pteris vittata. Plants were exposed to 1) 0.1 mM CrVI and 0, 0.25, 1.25 or 2.5 mM sulfate or 2) 0.25 mM sulfate and 0, 0.5, 2.5 or 5.0 mM CrVI for 1 d in hydroponics. P. vittata accumulated 26 and 1261 mg kg(-1) Cr in the fronds and roots at CrVI0.1, and 2197 and 1589 mg kg(-1) S in the fronds and roots at S0.25. Increasing sulfate concentrations increased Cr root concentrations by 16-66% and helped CrVI reduction to CrIII whereas increasing CrVI concentrations increased frond sulfate concentrations by 3-27%. Increasing sulfate concentrations enhanced TBARS concentrations in the biomass, indicating oxidative stress caused lipid peroxidation in plant cell membranes. However, addition of 0.25-2.5 mM sulfate alleviated CrVI's toxic effects and decreased TBARS from 23.5 to 9.46-12.3 μmol g(-1) FW. Though CrVI was supplied, 78-96% of CrIII was in the biomass, indicating efficient CrVI reduction to CrIII by P. vittata. The data indicated the amazing ability of P. vittata in Cr uptake at 289 mg kg(-1) h(-1) with little translocation to the fronds. These results indicated that P. vittata had potential in Cr phytoremediation in contaminated sites but further studies are needed to evaluate this potential. The facts that CrVI and sulfate helped each other in uptake by P. vittata suggest that CrVI was not competing with sulfate uptake in P. vittata. However, the mechanisms of how sulfate and CrVI enhance each other's accumulation in P. vittata need further investigation. PMID:26761595

  20. Elevated CO2 concentration increase the mobility of Cd and Zn in the rhizosphere of hyperaccumulator Sedum alfredii.

    PubMed

    Li, Tingqiang; Tao, Qi; Liang, Chengfeng; Yang, Xiaoe

    2014-05-01

    The effects of elevated CO2 on metal species and mobility in the rhizosphere of hyperaccumulator are not well understood. We report an experiment designed to compare the effects of elevated CO2 on Cd/Zn speciation and mobility in the rhizosphere of hyperaccumulating ecotype (HE) and a non-hyperaccumulating ecotype (NHE) of Sedum alfredii grown under ambient (350?ll(-1)) or elevated (800?ll(-1)) CO2 conditions. No difference in solution pH of NHE was observed between ambient and elevated CO2 treatments. For HE, however, elevated CO2 reduced soil solution pH by 0.22 unit, as compared to ambient CO2 conditions. Elevated CO2 increased dissolved organic carbon (DOC) and organic acid levels in soil solution of both ecotypes, but the increase in HE solution was much greater than in NHE solution. After the growth of HE, the concentrations of Cd and Zn in soil solution decreased significantly regardless of CO2 level. The visual MINTEQ speciation model predicted that Cd/Zn-DOM complexes were the dominant species in soil solutions, followed by free Cd(2+) and Zn(2+) species for both ecotypes. However, Cd/Zn-DOM complexes fraction in soil solution of HE was increased by the elevated CO2 treatment (by 8.01% for Cd and 8.47% for Zn, respectively). Resin equilibration experiment results indicated that DOM derived from the rhizosphere of HE under elevated CO2 (HE-DOM-E) (90% for Cd and 73% for Zn, respectively) showed greater ability to form complexes with Cd and Zn than those under ambient CO2 (HE-DOM-A) (82% for Cd and 61% for Zn, respectively) in the undiluted sample. HE-DOM-E showed greater ability to extract Cd and Zn from soil than HE-DOM-A. It was concluded that elevated CO2 could increase the mobility of Cd and Zn due to the enhanced formation of DOM-metal complexes in the rhizosphere of HE S. alfredii. PMID:24453019

  1. 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

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

    PubMed

    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 Se(VI), but a combination of passive and direct absorption occurred when supplemented with Se(IV) due to the partial oxidation of Se(IV) to Se(VI) in the rhizosphere. Higher molecular weight selenium species were more prevalent in the roots of plants supplemented with Se(IV), but in the leaves of plants supplemented with Se(VI) due to an increased translocation rate. When supplemented as As(III), arsenic is proposed to be passively absorbed as As(III) and partially oxidized to As(V) 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

  3. 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

  4. 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.

  5. 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.

  6. [Effects of Soil Moisture on Phytoremediation of As-Containinated Soils Using As-Hyperaccumulator Pteris vittata L].

    PubMed

    Liu, Qiu-xin; Yan, Xiu-lan; Liao, Xiao-yong; Lin, Long-yong; Yang, Jing

    2015-08-01

    A pot experiment was carried out to study the effects of soil moisture on the growth and arsenic uptake of As-hyperaccumulator Pteris vittata L. The results showed that the remediation efficiency of As was the highest when the soil moisture was between 35%-45%. P. vittata grew best under 45% water content, and its aboveground and underground plant dry weights were 2.95 g x plant(-1) and 11.95 g x plant(-1), respectively; the arsenic concentration in aboveground and roots was the highest under 35% water content, and 40% content was the best for accumulation of arsenic in P. vittata. Moreover, controlling the soil moisture to 35%-45% enhanced the conversion of As(V) to As(III) in aboveground plant, and promoted arsenic detoxification in P. vittata. These above results showed that soil moisture played an important role in the absorption and transport of arsenic by P. vittata. The results of this study can provide important guidance for the large-scale planting of P. vittata and the moisture management measures in engineering application. PMID:26592040

  7. 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

  8. Arsenic-induced plant growth of arsenic-hyperaccumulator Pteris vittata: Impact of arsenic and phosphate rock.

    PubMed

    Han, Yong-He; Yang, Guang-Mei; Fu, Jing-Wei; Guan, Dong-Xing; Chen, Yanshan; Ma, Lena Q

    2016-04-01

    Phosphate rock (PR) has been shown to promote plant growth and arsenic (As) uptake by As-hyperaccumulator Pteris vittata (PV). However, little is known about its behaviors in agricultural soils. In this study, impact of 50 mg kg(-1) As and/or 1.5% PR amendment on plant As accumulation and growth was investigated by growing PV for 90 d in three agricultural soils. While As amendment significantly increased plant As uptake and substantially promoted PV growth, the opposite was observed with PR amendment. Arsenic amendment increased plant frond As from 16.9-265 to 961-6017 mg kg(-1),whereas PR amendment lowered frond As to 10.2-216 mg kg(-1). The As-induced plant growth stimulation was 69-71%. While PR amendment increased plant Ca and P uptake, As amendment showed opposite results. The PV biomass was highly correlated with plant As at r = 0.82, but with weak correlations with plant Ca or P at r < 0.30. This study confirmed that 1) As significantly promoted PV growth, probably independent of Ca or P uptake, 2) PR amendment didn't enhance plant growth or As uptake by PV in agricultural soils with adequate available P, and 3) PV effluxed arsenite (AsIII) growing in agricultural soils. PMID:26874625

  9. 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.

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

    PubMed

    de Oliveira, Letzia Maria; Ma, Lena Q; Santos, Jorge A G; Guilherme, Luiz R G; Lessl, Jason T

    2014-01-01

    We investigated effects of arsenate (AsV), chromate (CrVI) and sulfate on As and Cr uptake and translocation by arsenic hyperaccumulator Pteris vittata (PV), which was exposed to AsV, CrVI and sulfate at 0, 0.05, 0.25 or 1.25mM for 2-wk in hydroponic system. PV was effective in accumulating large amounts of As (4598 and 1160mg/kg in the fronds and roots at 0.05mM AsV) and Cr (234 and 12,630mg/kg in the fronds and roots at 0.05mM CrVI). However, when co-present, AsV and CrVI acted as inhibitors, negatively impacting their accumulation in PV. Arsenic accumulation in the fronds was reduced by 92% and Cr by 26%, indicating reduced As and Cr translocation. However, addition of sulfate increased uptake and translocation of As by 26-28% and Cr by 1.63 fold. This experiment demonstrated that As and Cr inhibited each other in uptake and translocation by PV but sulfate enhanced As and Cr uptake and translocation by PV. PMID:24056188

  11. 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 200mgkg(-1) arsenate (AsV). They were isolated in presence of 10mM 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. 18.3mgL(-1)). In presence of 10mM 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

  12. Development of suitable hydroponics system for phytoremediation of arsenic-contaminated water using an arsenic hyperaccumulator plant Pteris vittata.

    PubMed

    Huang, Yi; Miyauchi, Keisuke; Inoue, Chihiro; Endo, Ginro

    2016-03-01

    In this study, we found that high-performance hydroponics of arsenic hyperaccumulator fern Pteris vittata is possible without any mechanical aeration system, if rhizomes of the ferns are kept over the water surface level. It was also found that very low-nutrition condition is better for root elongation of P. vittata that is an important factor of the arsenic removal from contaminated water. By the non-aeration and low-nutrition hydroponics for four months, roots of P. vittata were elongated more than 500 mm. The results of arsenate phytofiltration experiments showed that arsenic concentrations in water declined from the initial concentrations (50 μg/L, 500 μg/L, and 1000 μg/L) to lower than the detection limit (0.1 μg/L) and about 80% of arsenic removed was accumulated in the fern fronds. The improved hydroponics method for P. vittata developed in this study enables low-cost phytoremediation of arsenic-contaminated water and high-affinity removal of arsenic from water. PMID:26549187

  13. Impaired leaf CO2 diffusion mediates Cd-induced inhibition of photosynthesis in the Zn/Cd hyperaccumulator Picris divaricata.

    TOXLINE Toxicology Bibliographic Information

    Tang L; Ying RR; Jiang D; Zeng XW; Morel JL; Tang YT; Qiu RL

    2013-12-01

    Mechanisms of cadmium (Cd)-induced inhibition of photosynthesis in the Zn/Cd hyperaccumulator Picris divaricata were investigated using photosynthesis limitation analysis. P.divaricata seedlings were grown in nutrient solution containing 0, 5, 10, 25, 50, or 75?M Cd for 2 weeks. Total limitations to photosynthesis (TL) increased from 0% at 5?M Cd to 68.8% at 75?M Cd. CO2 diffusional limitation (DL) made the largest contribution to TL, accounting for 93-98% of TL in the three highest Cd treatments, compared to just 2-7% of TL attributable to biochemical limitation (BL). Microscopic imaging revealed significantly decreased stomatal density and mesophyll thickness in the three highest Cd treatments. Chlorophyll fluorescence parameters related to photosynthetic biochemistry (Fv/Fm, NPQ, ?PSII, and qP) were not significantly decreased by increased Cd supply. Our results suggest that increased DL in leaves is the main cause of Cd-induced inhibition of photosynthesis in P.divaricata, possibly due to suppressed function of mesophyll and stomata. Analysis of chlorophyll fluorescence showed that Cd supply had little effect on photochemistry parameters, suggesting that the PSII reaction centers are not a main target of Cd inhibition of photosynthesis in P.divaricata.

  14. Impaired leaf CO2 diffusion mediates Cd-induced inhibition of photosynthesis in the Zn/Cd hyperaccumulator Picris divaricata.

    PubMed

    Tang, Lu; Ying, Rong-Rong; Jiang, Dan; Zeng, Xiao-Wen; Morel, Jean-Louis; Tang, Ye-Tao; Qiu, Rong-Liang

    2013-12-01

    Mechanisms of cadmium (Cd)-induced inhibition of photosynthesis in the Zn/Cd hyperaccumulator Picris divaricata were investigated using photosynthesis limitation analysis. P.divaricata seedlings were grown in nutrient solution containing 0, 5, 10, 25, 50, or 75?M Cd for 2 weeks. Total limitations to photosynthesis (TL) increased from 0% at 5?M Cd to 68.8% at 75?M Cd. CO2 diffusional limitation (DL) made the largest contribution to TL, accounting for 93-98% of TL in the three highest Cd treatments, compared to just 2-7% of TL attributable to biochemical limitation (BL). Microscopic imaging revealed significantly decreased stomatal density and mesophyll thickness in the three highest Cd treatments. Chlorophyll fluorescence parameters related to photosynthetic biochemistry (Fv/Fm, NPQ, ?PSII, and qP) were not significantly decreased by increased Cd supply. Our results suggest that increased DL in leaves is the main cause of Cd-induced inhibition of photosynthesis in P.divaricata, possibly due to suppressed function of mesophyll and stomata. Analysis of chlorophyll fluorescence showed that Cd supply had little effect on photochemistry parameters, suggesting that the PSII reaction centers are not a main target of Cd inhibition of photosynthesis in P.divaricata. PMID:24077231

  15. 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

  16. 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 37.5mgkg(-1) AsV, As concentrations in the fronds and roots were 3655-5389 (89-91% AsIII) and 971-1467mgkg(-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 (120gg(-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

  17. Mixed arbuscular mycorrhizal (AM) fungal application to improve growth and arsenic accumulation of Pteris vittata (As hyperaccumulator) grown in As-contaminated soil.

    PubMed

    Leung, H M; Leung, A O W; Ye, Z H; Cheung, K C; Yung, K K L

    2013-08-01

    A greenhouse pot experiment was conducted to study the effects of three types of single inoculum [indigenous mycorrhizas (IM) isolated from As mine, Glomus mosseae (GM) and Glomus intraradices (GI)] and two types of mixed inoculum (mixed with IM and either GM or GI) on the growth response of Pteris vittata (hyperaccumulator) and Cynodon dactylon (non-hyperaccumulator) at three levels of As concentrations (0, 100 and 200mgkg(-1)). Both mycorrhizal plants exhibited significantly higher biomass, and N and P accumulation in its tissue than the control. Among the mycorrhizal inoculum, the mixed inoculum IM/GM promoted substantially higher mycorrhizal colonization and arsenate reductase activity in P. vittata than C. dactylon, among all As levels. The portion of Paris arbuscular mycorrhizal structure (observed in colonized roots) together with the highest As translocation factor of 10.2 in P. vittata inoculated with IM/GM was also noted. It was deduced that IM/GM inoculum may be the best choice for field inoculation at any contaminated lands as the inoculum exhibited better adaptation to variable environmental conditions and hence benefited the host plants. PMID:23755987

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

    PubMed

    Tlusto, Pavel; B?endov, Kate?ina; Szkov, Ji?ina; Najmanov, Jana; Koubov, 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 2.9kg ha(-1) (N. caerulescens) and up to 0.15kg ha(-1) (A. halleri), and in the case of Zn from 0.2 to 6.4kg ha(-1) (N. caerulescens) and up to 13.8kg.ha(-1) (A. halleri). Taking into account the 20cm 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

  19. 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

  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, Stphanie; Meyer, Claire-Lise; Castillo-Michel, Hiram; Testemale, Denis; Vantelon, Delphine; Saumitou-Laprade, Pierre; Verbruggen, Nathalie; Sarret, Graldine

    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. 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 : 1ω7c, 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

  2. 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, Ins; 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

  3. Expression of the ZNT1 Zinc Transporter from the Metal Hyperaccumulator Noccaea caerulescens Confers Enhanced Zinc and Cadmium Tolerance and Accumulation to Arabidopsis thaliana

    PubMed Central

    Schat, Henk; Aarts, Mark G. M.

    2016-01-01

    Prompt regulation of transition metal transporters is crucial for plant zinc homeostasis. NcZNT1 is one of such transporters, found in the metal hyperaccumulator Brassicaceae species Noccaea caerulescens. It is orthologous to AtZIP4 from Arabidopsis thaliana, an important actor in Zn homeostasis. We examined if the NcZNT1 function contributes to the metal hyperaccumulation of N. caerulescens. NcZNT1 was found to be a plasma-membrane located metal transporter. Constitutive overexpression of NcZNT1 in A. thaliana conferred enhanced tolerance to exposure to excess Zn and Cd supply, as well as increased accumulation of Zn and Cd and induction of the Fe deficiency response, when compared to non-transformed wild-type plants. Promoters of both genes were induced by Zn deficiency in roots and shoots of A. thaliana. In A. thaliana, the AtZIP4 and NcZNT1 promoters were mainly active in cortex, endodermis and pericycle cells under Zn deficient conditions. In N. caerulescens, the promoters were active in the same tissues, though the activity of the NcZNT1 promoter was higher and not limited to Zn deficient conditions. Common cis elements were identified in both promoters by 5’ deletion analysis. These correspond to the previously determined Zinc Deficiency Responsive Elements found in A. thaliana to interact with two redundantly acting transcription factors, bZIP19 and bZIP23, controlling the Zn deficiency response. In conclusion, these results suggest that NcZNT1 is an important factor in contributing to Zn and Cd hyperaccumulation in N. caerulescens. Differences in cis- and trans-regulators are likely to account for the differences in expression between A. thaliana and N. caerulescens. The high, constitutive NcZNT1 expression in the stele of N. caerulescens roots implicates its involvement in long distance root-to-shoot metal transport by maintaining a Zn/Cd influx into cells responsible for xylem loading. PMID:26930473

  4. 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.

  5. 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.

  6. A comparison of the dietary arsenic exposures from ingestion of contaminated soil and hyperaccumulating Pteris ferns used in a residential phytoremediation project.

    PubMed

    Ebbs, Stephen; Hatfield, Sarah; Nagarajan, Vinay; Blaylock, Michael

    2010-01-01

    Arsenic (As) hyperaccumulating ferns are used to phytoremediate As-contaminated soils, including soils in residential areas. This use may pose a health risk if children were to ingest these plants. Spider brake (Pteris cretica L.) plants were grown in sand spiked with arsenate, to produce tissue As concentrations (2000-4500 mg kg DW(-1)) typical of those observed in plants deployed for As phytoremediation. The fronds were subjected to a physiologically-based extraction test to estimate As bioaccessibility, which ranged from 3.4-20.5%. A scenario for human dietary exposure to As in an urban setting was then estimated for a child consuming 0.25 g DW of tissue. The calculation of dietary exposure took into account the As concentration in the fern pinnae, the bioaccessibility of As in the tissue, and the typical absorption of inorganic As by the gastrointestinal tract. The pinnae As concentrations and the calculated dietary exposures were used to create a non-linear regression model relating tissue As concentration to dietary exposure. Data from a phytoremediation project in a residential area using Pteris cretica and Pteris vittata (L.) were input into this model to project dietary As exposure in a residential phytoremediation setting. These exposures were compared to estimates of dietary As exposure from the consumption of soil. The results showed that dietary exposures to As from consumption of soil or pinnae tissue were similar and that estimates of dietary exposure were below the LOAEL value of 14 microg As kg(-1) d(-1). The results suggest that the hyperaccumulation of As in Pteris ferns during growth in moderately contaminated residential soils (e.g., < or = 100 mg As kg DW(-1)) does not represent an inherent risk or a risk substantially different from that posed by accidental ingestion of contaminated soil. PMID:20734633

  7. A comparison of the dietary arsenic exposures from ingestion of contaminated soil and hyperaccumulating Pteris ferns used in a residential phytoremediation project.

    TOXLINE Toxicology Bibliographic Information

    Ebbs S; Hatfield S; Nagarajan V; Blaylock M

    2010-01-01

    Arsenic (As) hyperaccumulating ferns are used to phytoremediate As-contaminated soils, including soils in residential areas. This use may pose a health risk if children were to ingest these plants. Spider brake (Pteris cretica L.) plants were grown in sand spiked with arsenate, to produce tissue As concentrations (2000-4500 mg kg DW(-1)) typical of those observed in plants deployed for As phytoremediation. The fronds were subjected to a physiologically-based extraction test to estimate As bioaccessibility, which ranged from 3.4-20.5%. A scenario for human dietary exposure to As in an urban setting was then estimated for a child consuming 0.25 g DW of tissue. The calculation of dietary exposure took into account the As concentration in the fern pinnae, the bioaccessibility of As in the tissue, and the typical absorption of inorganic As by the gastrointestinal tract. The pinnae As concentrations and the calculated dietary exposures were used to create a non-linear regression model relating tissue As concentration to dietary exposure. Data from a phytoremediation project in a residential area using Pteris cretica and Pteris vittata (L.) were input into this model to project dietary As exposure in a residential phytoremediation setting. These exposures were compared to estimates of dietary As exposure from the consumption of soil. The results showed that dietary exposures to As from consumption of soil or pinnae tissue were similar and that estimates of dietary exposure were below the LOAEL value of 14 microg As kg(-1) d(-1). The results suggest that the hyperaccumulation of As in Pteris ferns during growth in moderately contaminated residential soils (e.g., < or = 100 mg As kg DW(-1)) does not represent an inherent risk or a risk substantially different from that posed by accidental ingestion of contaminated soil.

  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. The Pb-hyperaccumulator aquatic fern Salvinia minima Baker, responds to Pb(2+) by increasing phytochelatins via changes in SmPCS expression and in phytochelatin synthase activity.

    PubMed

    Estrella-Gmez, N; Mendoza-Czatl, D; Moreno-Snchez, R; Gonzlez-Mendoza, D; Zapata-Prez, O; Martnez-Hernndez, A; Santamara, J M

    2009-03-01

    The relationship between accumulation of Pb(2+) and the activation of chelation and metal sequestration mechanisms mediated by phytochelatins (PC) was analyzed in the Pb(2+) hyperaccumulator aquatic fern Salvinia minima, after exposure to 40microM Pb(NO(3))(2). The tissue accumulation pattern of lead and the phytochelatin biosynthesis responses were analyzed in both, S. minima submerged root-like modified fronds (here named "roots"), and in its aerial leaf-like fronds ("leaves"). S. minima roots accumulated a significantly higher concentrations of Pb(+2) than leaves did. Accumulation of Pb(2+) in roots was bi-phasic with a first uptake phase reached after 3h exposure and a second higher uptake phase reached after 24h exposure. In leaves, a single delayed, smaller uptake phase was attained only after 9h of exposure. In roots lead accumulation correlated with an increased phytochelatin synthase (PCS) activity and an enhanced PC production. A higher proportion of polymerized PC(4) was observed in both tissues of exposed S. minima plants relative to unexposed ones, although a higher concentration of PC(4) was found in roots than in leaves. PCS activity and Pb(2+) accumulation was also higher in roots than in leaves. The expression levels of the S. minima PCS gene (SmPCS), in response to Pb(2+) treatment, were also evaluated. In S. minima leaves, the accumulation of Pb(2+) correlated with a marked increase in expression of SmPCS, suggesting a transcriptional regulation in the PCS activation and PC accumulation in this S. minima tissue. However, in roots, the basal expression of SmPCS was down-regulated after Pb(2+) treatment. This fact did not correlate with the later but strong increase in both, PCS activity and PC production; suggesting that the PC biosynthesis activation in S. minima roots occurs only by post-translational activation of PCS. Taken together, our data suggest that the accumulation of PC in S. minima is a direct response to Pb(2+) accumulation, and phytochelatins do participate as one of the mechanism to cope with Pb(2+) of this Pb-hyperaccumulator aquatic fern. PMID:19110323

  10. "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...

  11. Micropropagation of Myriophyllum alterniflorum (Haloragaceae) for stream rehabilitation: first in vitro culture and reintroduction assays of a heavy-metal hyperaccumulator immersed macrophyte.

    PubMed

    Delmail, David; Labrousse, Pascal; Hourdin, Philippe; Larcher, Laure; Moesch, Christian; Botineau, Michel

    2013-01-01

    Nowadays, submersed aquatic macrophytes play a key role in stream ecology and they are often used as biomonitors of freshwater quality. So, these plants appear as natural candidates to stream rehabilitation experiments. Among them, the stream macrophyte Myriophyllum alterniflorum is used recently as biomonitor and is potentially useful for the restoration of heavy-metal contaminated localities. The best way to obtain a mass production of watermilfoil plants is micropropagation. We developed in vitro culture of M. alterniflorum and the effects of five media on the plant development were assessed. Five morphological and four physiological endpoints were examined leading to the recommendation of the Murashige and Skoog medium for ecotoxicological studies on chlorophyllous parts, and of the Gaudet medium for root cytotoxicity and phytoremediation studies. Micropropagated clones were acclimatized in a synthetic medium and in situ reintroduction was performed efficiently. This is the first report of micropropagated plants transplantation in streams. The successful establishment of watermilfoil beds even in polluted areas strongly suggested that ecological restoration using micropropagated watermilfoil is a promising biotechnology for phytoremediation and rehabilitation of degraded areas. Moreover, high bioconcentration factors evidenced that watermilfoil hyperaccumulates Cd and Cu, and could be potentially used in phytoremediation studies. PMID:23819265

  12. 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

  13. 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

  14. Cadmium Sorption Characteristics of Soil Amendments and its Relationship with the Cadmium Uptake by Hyperaccumulator and Normal Plants in Amended Soils

    PubMed Central

    Sun, Yan; Wu, Qi-Tang; Lee, Charles C.C.; Li, Baoqin; Long, Xinxian

    2013-01-01

    In order to select appropriate amendments for cropping hyperaccumulator or normal plants on contaminated soils and establish the relationship between Cd sorption characteristics of soil amendments and their capacity to reduce Cd uptake by plants, batch sorption experiments with 11 different clay minerals and organic materials and a pot experiment with the same amendments were carried out. The pot experiment was conducted with Sedum alfredii and maize (Zea mays) in a co-cropping system. The results showed that the highest sorption amount was by montmorillonite at 40.82 mg/g, while mica was the lowest at only 1.83 mg/g. There was a significant negative correlation between the n value of Freundlich equation and Cd uptake by plants, and between the logarithm of the stability constant K of the Langmuir equation and plant uptake. Humic acids (HAs) and mushroom manure increased Cd uptake by S. alfredii, but not maize, thus they are suitable as soil amendments for the co-cropping S. alfredii and maize. The stability constant K in these cases was 0.14–0.16 L/mg and n values were 1.51–2.19. The alkaline zeolite and mica had the best fixation abilities and significantly decreased Cd uptake by the both plants, with K ≥ 1.49 L/mg and n ≥ 3.59. PMID:24912231

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    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.

  16. Effect of CO, NOx and SO2 on ROS production, photosynthesis and ascorbate-glutathione pathway to induce Fragariaannasa as a hyperaccumulator.

    PubMed

    Muneer, Sowbiya; Kim, Tae Hwan; Choi, Byung Chul; Lee, Beom Seon; Lee, Jeong Hyun

    2013-12-17

    A study was conducted to determine the effect of carbon monoxide (CO), nitroxide (NOx) and sulfur dioxide (SO2) on ROS production, photosynthesis and ascorbate-glutathione pathway in strawberry plants. The results showed that both singlet oxygen (O2(-1)) and hydrogen peroxide (H2O2) content increased in CO, NOx and SO2 treated strawberry leaves. A drastic reduction of primary metabolism of plants (photosynthesis), with the closure of stomata, resulted in a reduction of protein, carbohydrate and sucrose content due to production of reactive oxygen species (ROS) under prolonged exposure of gas stress. The resulting antioxidant enzymes were increased under a low dose of gas stress, whereas they were decreased due to a high dose of gas stress. Our results indicate that increased ROS may act as a signal to induce defense responses to CO, NOx and SO2 gas stress. The increased level of antioxidant enzymes plays a significant role in plant protection due to which strawberry plants can be used as a hyperaccumulator to maintain environmental pollution, however, the defense capacity cannot sufficiently alleviate oxidative damage under prolonged exposure of CO, NOx and SO2 stress. PMID:25460723

  17. Disruption of a rice gene for ?-glucan water dikinase, OsGWD1, leads to hyperaccumulation of starch in leaves but exhibits limited effects on growth

    PubMed Central

    Hirose, Tatsuro; Aoki, Naohiro; Harada, Yusuke; Okamura, Masaki; Hashida, Yoichi; Ohsugi, Ryu; Akio, Miyao; Hirochika, Hirohiko; Terao, Tomio

    2013-01-01

    To identify potential regulators of photoassimilate partitioning, we screened for rice mutant plants that accumulate high levels of starch in the leaf blades, and a mutant line leaf starch excess 1 (LSE1) was obtained and characterized. The starch content in the leaf blades of LSE1 was more than 10-fold higher than that in wild-type plants throughout the day, while the sucrose content was unaffected. The gene responsible for the LSE1 phenotype was identified by gene mapping to be a gene encoding ?-glucan water dikinase, OsGWD1 (Os06g0498400), and a 3.4-kb deletion of the gene was found in the mutant plant. Despite the hyperaccumulation of starch in their leaf blades, LSE1 plants exhibited no significant change in vegetative growth, presenting a clear contrast to the reported mutants of Arabidopsis thaliana and Lotus japonicus in which disruption of the genes for ?-glucan water dikinase leads to marked inhibition of vegetative growth. In reproductive growth, however, LSE1 exhibited fewer panicles per plant, lower percentage of ripened grains and smaller grains; consequently, the grain yield was lower in LSE1 plants than in wild-type plants by 20~40%. Collectively, although ?-glucan water dikinase was suggested to have universal importance in leaf starch degradation in higher plants, the physiological priority of leaf starch in photoassimilate allocation may vary among plant species. PMID:23750161

  18. A Vacuolar Arsenite Transporter Necessary for Arsenic Tolerance in the Arsenic Hyperaccumulating Fern Pteris vittata Is Missing in Flowering Plants[W][OA

    PubMed Central

    Indriolo, Emily; Na, GunNam; Ellis, Danielle; Salt, David E.; Banks, Jo Ann

    2010-01-01

    The fern Pteris vittata tolerates and hyperaccumulates exceptionally high levels of the toxic metalloid arsenic, and this trait appears unique to the Pteridaceae. Once taken up by the root, arsenate is reduced to arsenite as it is transported to the lamina of the frond, where it is stored in cells as free arsenite. Here, we describe the isolation and characterization of two P. vittata genes, ACR3 and ACR3;1, which encode proteins similar to the ACR3 arsenite effluxer of yeast. Pv ACR3 is able to rescue the arsenic-sensitive phenotypes of yeast deficient for ACR3. ACR3 transcripts are upregulated by arsenic in sporophyte roots and gametophytes, tissues that directly contact soil, whereas ACR3;1 expression is unaffected by arsenic. Knocking down the expression of ACR3, but not ACR3;1, in the gametophyte results in an arsenite-sensitive phenotype, indicating that ACR3 plays a necessary role in arsenic tolerance in the gametophyte. We show that ACR3 localizes to the vacuolar membrane in gametophytes, indicating that it likely effluxes arsenite into the vacuole for sequestration. Whereas single-copy ACR3 genes are present in moss, lycophytes, other ferns, and gymnosperms, none are present in angiosperms. The duplication of ACR3 in P. vittata and the loss of ACR3 in angiosperms may explain arsenic tolerance in this unusual group of ferns while precluding the same trait in angiosperms. PMID:20530755

  19. 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

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

    PubMed Central

    Vondráčková, Stanislava; Száková, Jiřina; Drábek, Ondřej; 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

  1. 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

  2. Unveiling Zn hyperaccumulation in Juncus acutus: implications on the electronic energy fluxes and on oxidative stress with emphasis on non-functional Zn-chlorophylls.

    PubMed

    Santos, D; Duarte, B; Caador, I

    2014-11-01

    Juncus acutus arises as possible hyperaccumulator specie, tolerating exogenous Zn concentrations as high as 60 mM. Zinc concentrations here detected in seedlings germinated in the presence high Zn concentrations, were above the described upper toxic levels for higher plants. Even at the highest Zn concentration, growth inhibition only accounted to approximately 30% of control seedlings biomass, presenting an EC?? value in the range of 10-20 mM of metal. PSII quantum yields showed a marked decline, reflection of changes in the thylakoid structure on the PSII electron donor sites. In fact, the electron transport rate was severely affected by Zn in seedlings exposed to higher Zn concentrations leading to a decrease in their maximum electronic transport rate and consequently presenting lower light saturation and lower photosynthetic efficiencies. Although light absorption capacity was not affected by Zn exposure and uptake, energy trapping flux in the photosynthetic apparatus and transport throughout the electronic chain was severely impaired. This lack of efficiency is related with non-functional Zn-chlorophylls formation. There was a strong linear correlation between exogenous Zn concentration applied and the concentration actually verified in the seedlings tissue with the concentration of both ZnChl a and b. There was also a gradual loss of connectivity between the antennae of the PSII units being this more evident at the higher Zn concentrations and thus impairing the energetic transport. The reduction in light harvesting efficiency, leads inevitably to the accumulation of redox energy inside the cells. To counteract ROS generation, all anti-oxidant enzymatic activities (except catalase) showed a proportional response to exogenous and in vivo Zn concentrations. Not only this plant appears to be highly tolerant to high Zn concentrations, but also it can overcome efficiently the damage produced during this uptake by efficiently dissipating the excessive cellular redox potential accumulated, essentially due to Zn incorporation into the chlorophyll molecule. PMID:25173758

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

    PubMed

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

    2015-09-01

    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 calcium(2+)/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

  4. LC-MS and GC-MS metabolite profiling of nickel(II) complexes in the latex of the nickel-hyperaccumulating tree Sebertia acuminata and identification of methylated aldaric acid as a new nickel(II) ligand.

    PubMed

    Callahan, Damien L; Roessner, Ute; Dumontet, Vincent; Perrier, Nicolas; Wedd, Anthony G; O'Hair, Richard A J; Baker, Alan J M; Kolev, Spas D

    2008-01-01

    Targeted liquid chromatography-mass spectrometry (LC-MS) technology using size exclusion chromatography and metabolite profiling based on gas chromatography-mass spectrometry (GC-MS) were used to study the nickel-rich latex of the hyperaccumulating tree Sebertia acuminata. More than 120 compounds were detected, 57 of these were subsequently identified. A methylated aldaric acid (2,4,5-trihydroxy-3-methoxy-1,6-hexan-dioic acid) was identified for the first time in biological extracts and its structure was confirmed by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. After citric acid, it appears to be one of the most abundant small organic molecules present in the latex studied. Nickel(II) complexes of stoichiometry NiII:acid=1:2 were detected for these two acids as well as for malic, itaconic, erythronic, galacturonic, tartaric, aconitic and saccharic acids. These results provide further evidence that organic acids may play an important role in the transport and possibly in the storage of metal ions in hyperaccumulating plants. PMID:17765935

  5. Selective uptake, distribution, and redistribution of (109)Cd, (57)Co, (65)Zn, (63)Ni, and (134)Cs via xylem and phloem in the heavy metal hyperaccumulator Solanum nigrum L.

    PubMed

    Wei, Shuhe; Anders, Iwona; Feller, Urs

    2014-06-01

    The focus of this article was to explore the translocation of (109)Cd, (57)Co, (65)Zn, (63)Ni, and (134)Cs via xylem and phloem in the newly found hyperaccumulator Solanum nigrum L. Two experiments with the uptake via the roots and transport of (109)Cd, (57)Co, and (65)Zn labeled by roots, and the redistribution of (109)Cd, (65)Zn, (57)Co, (63)Ni, and (134)Cs using flap label in S. nigrum in a hydroponic culture with a standard nutrient solution were conducted. The results showed that (109)Cd added for 24h to the nutrient medium of young plants was rapidly taken up, transferred to the shoot, and accumulated in the cotyledons and the oldest leaves but was not efficiently redistributed within the shoot afterward leading to a rather low content in the fruits. In contrast, (57)Co was more slowly taken up and released to the shoot, but afterward, this element was redistributed from older leaves to younger leaves and maturing fruits. (65)Zn was rapidly taken up and transferred to the shoot (mainly to the youngest leaves and not to the cotyledons). Afterward, this radionuclide was redistributed within the shoot to the youngest organs and finally accumulated in the maturing fruits. After flap labeling, all five heavy metals tested ((109)Cd, (57)Co, (65)Zn, (63)Ni, (134)Cs) were exported from the labeled leaf and redistributed within the plant. The accumulation in the fruits was most pronounced for (63)Ni and (65)Zn, while a relatively high percentage of (57)Co was finally found in the roots. (134)Cs was roughly in the middle of them. The transport of (109)Cd differed from that previously reported for wheat or lupin and might be important for the potential of S. nigrum to hyperaccumulate cadmium. PMID:24604268

  6. 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

  7. 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

  8. Thlaspi arvense (Pennycress) germination, development and yield potential

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress is being developed as an off-season rotation crop which precedes an annual soybean production. This rotation scheme may offer distinct advantages to farmers by providing additional farm income from an otherwise fallow season, with little impact on the subsequent soybean production. Penn...

  9. Thlaspi arvense (Pennycress) germination, bolting and mechanical harvest seed loss

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress is being developed as an off-season rotation crop between annual corn and soybean production. This rotation scheme may offer distinct advantages to farmers by providing additional farm income from an otherwise fallow season with little impact on the subsequent soybean production. The seed...

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. Phytoremediation of heavy metal polluted soils and water: progresses and perspectives.

    PubMed

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

    2008-03-01

    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

  15. Isolation and enrichment of the erucic acid from Thlaspi Arvense (Pennycress) oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress is being developed as an off-season rotation crop between annual corn and soybean production. This rotation scheme may offer distinct advantages to farmers by providing additional farm income from an otherwise fallow season with little impact on the subsequent soybean production. The seed...

  16. 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...

  17. Thlaspi arvense (Pennycress): An off-season energy crop within the corn-soybean rotation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress is being developed as an off-season rotation crop between annual corn and soybean production. This rotation scheme may offer distinct advantages to farmers by providing additional farm income from an otherwise fallow season with little impact on the subsequent soybean production. The seed...

  18. Thlaspi arvense (Pennycress) as a biodiesel in a one year-two crop rotation with soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increased demand for energy has generated renewed interest in the development of oilseed crops. The short term answer to biodiesel has always been soybean. Unfortunately, soybean oil has several shortcomings in its effort to supply the U.S. market. First, and foremost, is the fact that if all curr...

  19. Development of a non-dormant germplasm from Thlaspi Arvense (Pennycress)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress is being developed as an off-season rotation crop between annual corn and soybean production. This rotation scheme may offer distinct advantages to farmers by providing additional farm income from an otherwise fallow season with little impact on the subsequent soybean production. The seed...

  20. 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...

  1. 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...

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

    PubMed

    Keller, Catherine; Ludwig, Christian; Davoli, Frdric; Wochele, Jrg

    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

  3. 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 (Miscanthusנgiganteus) 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

  4. 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.

  5. 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.

  6. Bioenergy crops grown for hyperaccumulation of phosphorus in the delmarva peninsula and their biofuels potential

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Herbaceous bioenergy crops, including sorghum, switchgrass, and miscanthus, were evaluated for their potential as phytoremedators for the uptake of phosphorus in the Delmarva Peninsula and their subsequent conversion to biofuel intermediates (bio-oil) by fast pyrolysis using pyrolysis-gas chromatogr...

  7. 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...

  8. Predicting arsenic bioavailability to hyperaccumulator Pteris vittata in arsenic-contaminated soils.

    PubMed

    Gonzaga, Maria Isidria Silva; Ma, Lena Q; Pacheco, Edson Patto; dos Santos, Wallace Melo

    2012-12-01

    Using chemical extraction to evaluate plant arsenic availability in contaminated soils is important to estimate the time frame for site cleanup during phytoremediation. It is also of great value to assess As mobility in soil and its risk in environmental contamination. In this study, four conventional chemical extraction methods (water, ammonium sulfate, ammonium phosphate, and Mehlich III) and a new root-exudate based method were used to evaluate As extractability and to correlate it with As accumulation in P. vittata growing in five As-contaminated soils under greenhouse condition. The relationship between different soil properties, and As extractability and plant As accumulation was also investigated. Arsenic extractability was 4.6%, 7.0%, 18%, 21%, and 46% for water, ammonium sulfate, organic acids, ammonium phosphate, and Mehlich III, respectively. Root exudate (organic acids) solution was suitable for assessing As bioavailability (81%) in the soils while Mehlich III (31%) overestimated the amount of As taken up by plants. Soil organic matter, P and Mg concentrations were positively correlated to plant As accumulation whereas Ca concentration was negatively correlated. Further investigation is needed on the effect of Ca and Mg on As uptake by P. vittata. Moreover, additional As contaminated soils with different properties should be tested. PMID:22908656

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

    PubMed

    Mathews, Shiny; Ma, Lena Q; Rathinasabapathi, Bala; Natarajan, Seenivasan; Saha, Uttam K

    2010-11-01

    This study determined the role of plant and microbes in arsenite (AsIII) oxidation in the growth media and the location of AsIII oxidation and arsenate (AsV) reduction in Pteris vittata tissues. P. vittata grew in 0.10-0.27mM AsV or AsIII solution under aerated or sterile condition for 1h to 14d. Arsenic speciation was conducted in the growth media, biomass (roots, rhizomes, rachis, pinnae, and fronds), and sap (rhizomes and fronds). Arsenite was rapidly oxidized in the growth media by microbes (18-67% AsV after 1d) and was then further oxidized in the roots of P. vittata (35% AsV in the roots growing in AsIII media). While limited reduction occurred in the roots (7-8% as AsIII), AsV reduction mostly occurred in the rhizomes (68-71% as AsIII) and pinnae (>90% as AsIII) of P. vittata. Regardless AsIII or AsV was supplied, AsV dominated in the roots while AsIII dominated in the rhizomes and fronds. AsIII translocation from the roots to the fronds was more rapid than AsV. This study shed new insights into arsenic transformation in the growth media and P. vittata biomass and raise new question into the tissue distribution of arsenic reducing and oxidizing enzymes in P. vittata. PMID:20566284

  10. The major parameters on biomass pyrolysis for hyperaccumulative plants - A review.

    PubMed

    Dilks, R T; Monette, F; Glaus, M

    2016-03-01

    Phytoextraction is one of the main phytoremediation techniques and it has often been described as a potentially feasible in situ soil decontamination method of large amounts of heavy metals, organic pollutants and explosive compounds. As this remediation technique is approaching extensive on-field experimentation and commercialization, research focus is on investigating new ways to achieve the valorisation of its by-products. Biomass pyrolysis represents a key step to numerous valorisation options and it is characterized by differential output products that are determined by the operating conditions of the process and the characteristics of the input. However, when used to valorise plants that have undergone significant metal uptake, this strategy involves some new aspects related to harvest, procedure and final product reutilization. This paper reviews the studies made on biomass pyrolysis of plants with emphasis on the differential quality and distribution of pyrolysis products in relation with the variables of the process and the metal-rich phytoextraction feedstock properties. By investigating these parameters, this survey provides indications on ways to optimize the valorisation of phytoremediation by-products through biomass pyrolysis. PMID:26741543

  11. 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...

  12. 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 ...

  13. Zinc Hyperaccumulation in Squirrelfish (Holocentrus adscenscionis) and Its Role in Embryo Viability

    PubMed Central

    Glover, Chris N.; Capo, Tom; Walsh, Patrick J.; Hogstrand, Christer

    2012-01-01

    Female squirrelfish (Fam. Holocentridae) can accumulate and temporarily sequester copious amounts of zinc (Zn) in their livers. There, it is initially compartmentalized before a subsequent, estrogen-triggered redistribution to the ovaries. Here we show that cellular uptake of Zn is also influenced by estrogen signaling, and that estrogen increases concentrations of the plasma Zn-binding protein vitellogenin (VTG). However, estrogen-mediated increases in VTG are not sufficient to accommodate the magnitude of hepato-ovarian Zn transfer in female squirrelfish (Holocentrus adscensionis). These findings suggest that holocentrids have acquired the ability to use hormonal cues to drive hepatic uptake and storage of Zn, signal for its physiological redistribution, and influence the capacity for systemic transport of Zn beyond the mediation of increased plasma VTG concentrations. Such specific adaptations suggest an advantage for the oocyte, which is corroborated in further studies where we determined that oocyte Zn concentrations are positively correlated with egg viability in captive-spawned squirrelfish. The novel nature of these findings underlies the importance of Zn in squirrelfish reproductive biology. PMID:23056248

  14. A new process for nickel ammonium disulfate production from ash of the hyperaccumulating plant Alyssum murale.

    PubMed

    Barbaroux, R; Plasari, E; Mercier, G; Simonnot, M O; Morel, J L; Blais, J F

    2012-04-15

    The extraction of nickel (Ni) from ultramafic soils by phytomining can be achieved using Alyssum murale cultures. This study presents a new process for the valorization of Ni accumulated by this plant through the production of a Ni ammonium disulfate salt (Ni(NH(4))(2)(SO(4))(2).6H(2)O). The process comprises an initial leaching of the ashes of A. murale with a sulphuric acid solution (1.9 M H(2)SO(4), T=95 C, t=240 min, TS=150 g ash L(-1)), producing a leachate rich in Ni (10.2 g Ni L(-1); 96% Ni solubilisation), Mg, P, K, Fe, Ca and Al. The pH of the acid leachate is increased to 5.0 with NaOH (5M), followed by an evaporation step which produced a purified solution rich in Ni (21.3 g NiL(-1)) and an iron hydroxide precipitate. The cold crystallization (T=2 C, t=6h) of this solution by the stoichiometric addition ( 1.2) of ammonium sulfate generates a Ni ammonium disulfate salt, containing 13.2% Ni, that is potentially valuable to industry. PMID:22405560

  15. Comparison of sup 14 C-GA sub 12 - aldehyde metabolism in thermo- and non-induced shoot tips of Thlaspi arvense L

    SciTech Connect

    Hazebroek, J.P.; Metzger, J.D. )

    1989-04-01

    The metabolism of exogenous {sup 14}C-GA{sub 12}-aldehyde by the shoot tips of induced and noninduced field pennycress plants was compared. Both the rate of metabolism and the qualitative pattern of metabolites produced six hours after application were similar in induced and noninduced plants. The 2 major metabolites were identified by GC-MS as GA{sub 12} and an isomer of GA{sub 19}. This latter compound, however, does not appear to be native to field pennycress. Small amounts of {sup 14}C-GA{sub 12}-aldehyde were also incorporated into GA{sub 19, 20} and {sub 44}. In addition, a radioactive compound with chromatographic properties similar to GA{sub 9} was observed in plants from both treatments. These results coupled with our previous studies on kaurenoic acid metabolism indicate that the limiting step(s) in GA biosynthesis in noninduced field penny cress shoot tips lies between kaurenoic acid and GA{sub 12}-aldehyde.

  16. Identifying root exudates in field contaminated soil systems

    NASA Astrophysics Data System (ADS)

    Rosenfeld, C.; Martinez, C. E.

    2012-12-01

    Carbon (C) compounds exuded from plant roots comprise a significant and reactive fraction of belowground C pools. These exudates substantially alter the soil directly surrounding plant roots and play a vital role in the global C cycle, soil ecology, and ecosystem mobility of both nutrients and contaminants. In soils, the solubility and bioavailability of metals such as iron, zinc, and cadmium are intricately linked to the quantity and chemical characteristics of the C compounds allocated to the soil by plants. Cadmium (Cd), a toxic heavy metal, forms stronger bonds with reduced S- and N-containing compounds than with carboxylic acids, which may influence exudate composition in hyperaccumulator and tolerant plants grown in Cd contaminated soils. We hypothesize that hyperaccumulator plants will exude a larger quantity of aromatic N and chelating di- and tri-carboxylic acid molecules, while plants that exclude heavy metals from uptake will exude a larger proportion of reduced S containing molecules. This study examines how a variety of techniques can measure the low concentrations of complex organic mixtures exuded by hyperaccumulator and non-hyperaccumulator plants grown in Cd-contaminated soils. Two congeneric plants, Thlaspi caerulescens (Ganges ecotype), and T. caerulescens (Prayon ecotype) were grown in 0.5 kg pots filled with Cd-contaminated field soils from Chicago, IL. Field soils were contaminated as a result of the application of contaminated biosolids in the 1960's and 1970's. Pots were fitted for rhizon soil moisture samplers, micro-lysimeters developed for in situ collection of small volumes in unsaturated soils, prior to planting. Plants were grown for 8 weeks before exudate collection. After the 8 weeks of growth, a pulse-chase isotope tracer method using the C stable isotope, 13C, was employed to differentiate plant-derived compounds from background soil and microbial-derived compounds. Plants were placed in a CO2 impermeable chamber, and the soil surface was covered by CO2 impermeable sheets to ensure that all 13C in the soil results from photoassimilated C released by roots and not soil-atmosphere gas exchange. Ambient CO2 was drawn down in the system until the CO2 concentration within the tent was less than 50 ppm, after which the labeled 13CO2 was introduced, returning the CO2 concentration to the ambient level (~375 ppm). The CO2 pulse lasted for 60 minutes to allow enough time for 13C assimilation within the plants. In order to determine the ideal sampling time, soil pore water samples were extracted every 1-2 hours following the 13C pulse application, over the course of 24 hours. Samples were analyzed for delta 13C as well as %C, and results indicate that the greatest plant-derived dissolved organic C is present at about 6 hours following the 13C pulse. A second experiment will also be conducted using a combination of NMR and mass spectrometry methods to obtain detailed information regarding chemical structures within exudate samples.

  17. 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.

  18. Chelant-assisted phytoextraction and accumulation of Zn by Zea mays.

    PubMed

    Gheju, M; Stelescu, I

    2013-10-15

    Zea mays plants were exposed to soils with concentrations of Zn ranging from 64 to 1800 mg kg(-1) dw, and the efficiency of three selected chelating agents (trisodium citrate (CI), disodium oxalate (OX) and disodium dihydrogen ethylene-diamine-tetraacetate (EDTA)) in enhancing metal phytoextraction was compared. Zn concentration in plant tissues increased in conjunction with the metal concentration of the soil. EDTA was found to be the most efficient chelating amendment, increasing concentrations of Zn in shoots from 88 mg kg(-1) dw, at 64 mg kg(-1) dw soil, to 8026 mg kg(-1) dw at 1800 mg kg(-1) dw soil. The overall orders of BCFs and TFs which resulted from this study are: EDTA > H2O > OX > CI, and EDTANa2 > OX > CI > H2O, respectively. The more effective uptake of Zn by plants for the control treatment (distilled water only) than for CI and OX was attributed to the neutral or slightly alkaline pH of the two chelant irrigation solutions. Instead, EDTA had a favorable effect on Zn uptake from soil due to its additive chelating and acidifying properties. Among the three chelants, only EDTA significantly increased the Zn phytoextraction potential of Z. mays, while CI and OX induced a low metal uptake from soil by plants. Although Z. mays has a lower Zn accumulation capacity than the hyperaccumulator Thlaspi caerulescens, it could be considered as a potential phytoremediator of soils with elevated Zn concentrations, especially when metal pollution extends to depths greater than 20 cm. PMID:23845956

  19. 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

  20. 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

  1. Refeeding-Induced Brown Adipose Tissue Glycogen Hyper-Accumulation in Mice Is Mediated by Insulin and Catecholamines

    PubMed Central

    Carmean, Christopher M.; Bobe, Alexandria M.; Yu, Justin C.; Volden, Paul A.; Brady, Matthew J.

    2013-01-01

    Brown adipose tissue (BAT) generates heat during adaptive thermogenesis through a combination of oxidative metabolism and uncoupling protein 1-mediated electron transport chain uncoupling, using both free-fatty acids and glucose as substrate. Previous rat-based work in 1942 showed that prolonged partial fasting followed by refeeding led to a dramatic, transient increase in glycogen stores in multiple fat depots. In the present study, the protocol was replicated in male CD1 mice, resulting in a 2000-fold increase in interscapular BAT (IBAT) glycogen levels within 4–12 hours (hr) of refeeding, with IBAT glycogen stores reaching levels comparable to fed liver glycogen. Lesser effects occurred in white adipose tissues (WAT). Over the next 36 hr, glycogen levels dissipated and histological analysis revealed an over-accumulation of lipid droplets, suggesting a potential metabolic connection between glycogenolysis and lipid synthesis. 24 hr of total starvation followed by refeeding induced a robust and consistent glycogen over-accumulation similar in magnitude and time course to the prolonged partial fast. Experimentation demonstrated that hyperglycemia was not sufficient to drive glycogen accumulation in IBAT, but that elevated circulating insulin was sufficient. Additionally, pharmacological inhibition of catecholamine production reduced refeeding-induced IBAT glycogen storage, providing evidence of a contribution from the central nervous system. These findings highlight IBAT as a tissue that integrates both canonically-anabolic and catabolic stimulation for the promotion of glycogen storage during recovery from caloric deficit. The preservation of this robust response through many generations of animals not subjected to food deprivation suggests that the over-accumulation phenomenon plays a critical role in IBAT physiology. PMID:23861810

  2. 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

  3. 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

  4. Effect of fertilizers on Cd uptake of Amaranthus hypochondriacus, a high biomass, fast growing and easily cultivated potential Cd hyperaccumulator.

    PubMed

    Li, Ning Yu; Fu, Qing Lin; Zhuang, Ping; Guo, Bing; Zou, Bi; Li, Zhi An

    2012-02-01

    In a greenhouse pot experiment, we assessed the phytoextraction potential for Cd of three amaranth cultivars (Amaranthus hypochondriacus L. Cvs. K112, R104, and K472) and the effect of application of N, NP, and NPK fertilizer on Cd uptake of the three cultivars from soil contaminated with 5 mg kg(-1) Cd. All three amaranth cultivars had high levels of Cd concentration in their tissues, which ranged from 95.1 to 179.1 mg kg(-1) in leaves, 58.9 to 95.4 mg kg(-1) in stems, and 62.4 to 107.2 mg kg(-1) in roots, resulting in average bioaccumulation factors ranging from 17.7 to 29.7. Application of N, NP, or NPK fertilizers usually increased Cd content in leaves but decreased Cd content in stem and root. Fertilizers of N or NP combined did not substantially increase dry biomass of the 3 cultivars, leading to a limited increment of Cd accumulation. NPK fertilizer greatly increased dry biomass, by a factor of 2.7-3.8, resulting in a large increment of Cd accumulation. Amaranth cultivars (K112, R104, and K472) have great potential in phytoextraction of Cd contaminated soil. They have the merits of high Cd content in tissues, high biomass, easy cultivation and little effect on Cd uptake by fertilization. PMID:22567702

  5. Accumulation and tolerance characteristics of cadmium in Chlorophytum comosum: a popular ornamental plant and potential Cd hyperaccumulator.

    PubMed

    Wang, Youbao; Yan, Aolei; Dai, Jie; Wang, NanNan; Wu, Dan

    2012-01-01

    The effects on the growth, physiological indexes and the cadmium (Cd) accumulation in Chlorophytum comosum under Cd stress were examined by pot-planting. The results showed that the tolerance index (TI) of C. comosum were all above 100 in soil Cd concentration of 100 mg kg(-1). The O(2?)? production rate and electrical conductivity of C. comosum were significantly positively correlated to Cd adding-concentration while the MDA content increased and had significant differences with the control. The activities of SOD, CAT, and POD all rose significantly in lower Cd concentration and the Cd threshold of them were around 10, 50 and 20 mg kg(-1), respectively. The Cd in C. comosum root and aboveground part reached 1,522 and 8655 mg kg(-1), respectively, in Cd concentration of soil up to 200 mg kg(-1). For the advantages of high tolerance, high accumulation, and high ornamental value, C. comosum may have tremendous application value in the treatment of Cd-contaminated soils. PMID:21625926

  6. Lead accumulation reduces photosynthesis in the lead hyper-accumulator Salvinia minima Baker by affecting the cell membrane and inducing stomatal closure.

    PubMed

    Leal-Alvarado, Daniel A; Espadas-Gil, Francisco; Senz-Carbonell, Luis; Talavera-May, Carlos; Santamara, Jorge M

    2016-02-01

    Salvinia minima Baker accumulates a fair amount of lead in its tissues; however, no studies have investigated the effect of lead on the physiological processes that affect photosynthesis in this species. The objective of the present study was to assess whether the high amounts of lead accumulated by S. minima can affect its photosynthetic apparatus. The physiological changes in the roots and leaves in response to lead accumulation were analyzed. An exposure to 40?M Pb(NO3)2 for 24h (first stage) was sufficient to reduce the photosynthetic rate (Pn) by 44%. This reduction in Pn was apparently the result of processes at various levels, including damage to the cell membranes (mainly in roots). Interestingly, although the plants were transferred to fresh medium without lead for an additional 24h (second stage), Pn not only remained low, but was reduced even further, which was apparently related to stomatal closure, and may have led to reduced CO2 availability. Therefore, it can be concluded that lead exposure first decreases the photosynthetic rate by damaging the root membrane and then induces stomatal closure, resulting in decreased CO2 availability. PMID:26742090

  7. 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

  8. Bioaccessibility versus bioavailability of essential (Cu, Fe, Mn, and Zn) and toxic (Pb) elements from phyto hyperaccumulator Pistia stratiotes: potential risk of dietary intake.

    PubMed

    ?adkov, Zuzana; Szkov, Ji?ina; Miholov, Daniela; Horkov, Barbora; Kopeck, Old?ich; K?ivsk, Daniela; Langrov, Iva; Tlusto, Pavel

    2015-03-01

    Aquatic weeds are widely used as animal feed in developing countries. However, information about element bioavailability from these plants is lacking. A combination of an in vitro method [physiologically based extraction test (PBET)] and an in vivo feeding trial was used in this study to investigate potential element bioaccessibility and estimated bioavailability of Pistia stratiotes (PS). Cu, Fe, Mn, Zn, and Pb concentrations in PS biomass, artificial gastrointestinal fluids, and rat tissues were determined using atomic absorption spectrometry with electrothermal atomization and inductively coupled plasma-atomic emission spectrometry. PS exhibited elevated Fe, Mn, and Pb levels. The PBET revealed high bioaccessibility of all monitored elements from PS biomass. The results of the in vivo trial were inconsistent with those of the PBET, because animals fed PS exhibited low levels of essential elements in the tissues. The consumption of a PS-supplemented diet significantly decreased total Fe levels and increased the total level of accumulation of Pb in exposed animals. Significantly reduced amounts of essential elements in the intestinal walls indicated a potential disruption in nutrient gastrointestinal absorption in animals fed PS. PMID:25664561

  9. Removal of Ni(II) and Cu(II) ions using native and acid treated Ni-hyperaccumulator plant Alyssum discolor from Turkish serpentine soil.

    PubMed

    Bayramoglu, Gulay; Arica, M Yakup; Adiguzel, Nezaket

    2012-09-01

    Alyssum discolor biomass was collected from serpentine soil and was used for removal of metal ions. The plant species grown on serpentine soils are known to be rich with metals ions and thus have more capability for accumulating heavy metals. Native and acid-treated biomass of A. discolor (A. discolor) were utilized for the removal of Ni(II) and Cu(II) ions from aqueous solutions. The effects of contact time, initial concentration, and pH on the biosorption of Ni(II) and Cu(II) ions were investigated. Biosorption equilibrium was established in about 60 min. The surface properties of the biomass preparations were varied with pH, and the maximum amounts of Ni(II) and Cu(II) ions on both A. discolor biomass preparations were adsorbed at pH 5.0. The maximum biosorption capacities of the native, and acid-treated biomass preparations for Ni(II) were 13.1 and 34.7 mgg(-1) and for Cu(II) 6.15 and 17.8 mgg(-1) dry biomass, respectively. The biosorption of Ni(II) and Cu(II) ions from single and binary component systems can be successfully described by Langmuir and Freundlich isotherms. When the heavy metal ions were in competition, the amounts of biosorbed metal ions on the acid treated plant biomass were found to be 0.542 mmolg(-1) for Ni(II) and 0.162 mmolg(-1) for Cu(II), the A. discolor biomass was significantly selective for Ni(II) ions. The information gained from these studies was expected to indicate whether the native, and acid-treated forms can have the potential to be used for the removal and recovery of Ni(II) ions from wastewaters. PMID:22608134

  10. 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.

  11. 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.

  12. Zn-bis-glutathionate is the best co-substrate of the monomeric phytochelatin synthase from the photosynthetic heavy metal-hyperaccumulator Euglena gracilis.

    PubMed

    García-García, Jorge D; Girard, Lourdes; Hernández, Georgina; Saavedra, Emma; Pardo, Juan P; Rodríguez-Zavala, José S; Encalada, Rusely; Reyes-Prieto, Adrián; Mendoza-Cózatl, David G; Moreno-Sánchez, Rafael

    2014-03-01

    The phytochelatin synthase from photosynthetic Euglena gracilis (EgPCS) was analyzed at the transcriptional, kinetic, functional, and phylogenetic levels. Recombinant EgPCS was a monomeric enzyme able to synthesize, in the presence of Zn(2+) or Cd(2+), phytochelatin2-phytochelatin4 (PC2-PC4) using GSH or S-methyl-GS (S-methyl-glutathione), but not γ-glutamylcysteine or PC2 as a substrate. Kinetic analysis of EgPCS firmly established a two-substrate reaction mechanism for PC2 synthesis with Km values of 14-22 mM for GSH and 1.6-2.5 μM for metal-bis-glutathionate (Me-GS2). EgPCS showed the highest Vmax and catalytic efficiency with Zn-(GS)2, and was inactivated by peroxides. The EgPCS N-terminal domain showed high similarity to that of other PCSases, in which the typical catalytic core (Cys-70, His-179 and Asp-197) was identified. In contrast, the C-terminal domain showed no similarity to other PCSases. An EgPCS mutant comprising only the N-terminal 235 amino acid residues was inactive, suggesting that the C-terminal domain is essential for activity/stability. EgPCS transcription in Euglena cells was not modified by Cd(2+), whereas its heterologous expression in ycf-1 yeast cells provided resistance to Cd(2+) stress. Phylogenetic analysis of the N-terminal domain showed that EgPCS is distant from plants and other photosynthetic organisms, suggesting that it evolved independently. Although EgPCS showed typical features of PCSases (constitutive expression; conserved N-terminal domain; kinetic mechanism), it also exhibited distinct characteristics such as preference for Zn-(GS)2 over Cd-(GS)2 as a co-substrate, a monomeric structure, and ability to solely synthesize short-chain PCs, which may be involved in conferring enhanced heavy-metal resistance. PMID:24464102

  13. 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 ...

  14. A member of the Phosphate transporter 1 (Pht1) family from the arsenic-hyperaccumulating fern Pteris vittata is a high-affinity arsenate transporter.

    PubMed

    DiTusa, Sandra Feuer; Fontenot, Elena B; Wallace, Robert W; Silvers, Molly A; Steele, Thomas N; Elnagar, Alia H; Dearman, Kelsey M; Smith, Aaron P

    2016-01-01

    Pteris vittata exhibits enhanced arsenic uptake, but the corresponding mechanisms are not well known. The prevalent form of arsenic in most soils is arsenate, which is a phosphate analog and a substrate for Phosphate transporter 1 (Pht1) transporters. Herein we identify and characterize three P. vittata Pht1 transporters. Pteris vittata Pht1 cDNAs were isolated and characterized via heterologous expression in Saccharomyces cerevisiae (yeast) and Nicotiana benthamiana leaves. Expression of the PvPht1 loci in P. vittata gametophytes was also examined in response to phosphate deficiency and arsenate exposure. Expression of each of the PvPht1 cDNAs complemented the phosphate uptake defect of a yeast mutant. Compared with yeast cells expressing Arabidopsis thaliana Pht1;5, cells expressing PvPht1;3 were more sensitive to arsenate, and accumulated more arsenic. Uptake assays with yeast cells and radiolabeled (32) P revealed that PvPht1;3 and AtPht1;5 have similar affinities for phosphate, but the affinity of PvPht1;3 for arsenate is much greater. In P. vittata gametophytes, PvPht1;3 transcript levels increased in response to phosphate (Pi) deficiency and arsenate exposure. PvPht1;3 is induced by Pi deficiency and arsenate, and encodes a phosphate transporter that has a high affinity for arsenate. PvPht1;3 probably contributes to the enhanced arsenate uptake capacity and affinity exhibited by P. vittata. PMID:26010225

  15. 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...

  16. 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...

  17. 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 ...

  18. 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...

  19. 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...

  20. Advancements of pennycress as a biofuel and the synthesis of estolides thereof

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress (Thlaspi arvense L.) is being developed as an off-season rotation crop between annual corn and soybean production. This rotation scheme may offer distinct advantages to farmers by providing additional farm income from an otherwise fallow season with little impact on the subsequent soybean...

  1. Synthesis and physical properties of pennycress estolide 2-ethylhexyl esters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress (Thlaspi arvense L.) is a new crop that is currently being developed as an off-season rotation crop between annual corn and soybean production in Central Illinois by USDA-NCAUR. This rotation scheme may offer distinct advantages to farmers by providing additional farm income from an other...

  2. Lubrication properties of new crop oils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oils from new crops such as lesquerella (Lesquerella fendleri), field pennycress (Thlaspi arvense L.), meadowfoam (Limnanthes alba L.), and cuphea PSR-23 (Cuphea viscosissima Cuphea lanceolata) were investigated and compared with vegetable oils from commodity crops such as castor, corn, and soybea...

  3. 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 ...

  4. 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...

  5. Effects of planting depth on field establishment of pennycress and light conditions on seed germination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress (Thlaspi arvense), is a promising oilseed (36% oil) with potential for biofuels and another industrial uses. A winter annual, it may be feasible for use in Midwestern double cropping systems. However, agronomic and biological issues should be studied in order to understand and overcome pr...

  6. Seed oil development of pennycress under field conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress (Thlaspi sp) has been targeted as a potential oilseed for the biofuels industry. Its seeds contain ~36% oil, where erucic acid is the major fatty acid presented with 38.1%. Additionally, the physical proprieties of the methyl esters are in the range to satisfy the needs of the biodiesel m...

  7. Extraction of proteins from pennycress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress (Thlaspi arvense L.)has recently been found to have value as a source of biodiesel. Not only does it provide a high yield of quality oil, but perhaps more importantly, it can be planted after the harvest of traditional crops. It will grow through the winter (on days warmer than 0 C) and...

  8. 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...

  9. 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...

  10. 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...

  11. 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 ...

  12. 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...

  13. 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

  14. 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

    Po?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

  15. 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

  16. Classification and identification of metal-accumulating plant species by cluster analysis.

    PubMed

    Yang, Wenhao; Li, He; Zhang, Taoxiang; Sen, Lin; Ni, Wuzhong

    2014-09-01

    Identification and classification of metal-accumulating plant species is essential for phytoextraction. Cluster analysis is used for classifying individuals based on measured characteristics. In this study, classification of plant species for metal accumulation was conducted using cluster analysis based on a practical survey. Forty plant samples belonging to 21 species were collected from an ancient silver-mining site. Five groups such as hyperaccumulator, potential hyperaccumulator, accumulator, potential accumulator, and normal accumulating plant were graded. For Cd accumulation, the ancient silver-mining ecotype of Sedum alfredii was treated as a Cd hyperaccumulator, and the others were normal Cd-accumulating plants. For Zn accumulation, S. alfredii was considered as a potential Zn hyperaccumulator, Conyza canadensis and Artemisia lavandulaefolia were Zn accumulators, and the others were normal Zn-accumulating plants. For Pb accumulation, S. alfredii and Elatostema lineolatum were potential Pb hyperaccumulators, Rubus hunanensis, Ajuga decumbens, and Erigeron annuus were Pb accumulators, C. canadensis and A. lavandulaefolia were potential Pb accumulators, and the others were normal Pb-accumulating plants. Plant species with the potential for phytoextraction were identified such as S. alfredii for Cd and Zn, C. canadensis and A. lavandulaefolia for Zn and Pb, and E. lineolatum, R. hunanensis, A. decumbens, and E. annuus for Pb. Cluster analysis is effective in the classification of plant species for metal accumulation and identification of potential species for phytoextraction. PMID:24888623

  17. The potential for heavy metal decontamination

    SciTech Connect

    Baker, A.J.M.; McGrath, S.P.; Sidoli, C.M.D.; Reeves, R.D.

    1996-12-31

    Preliminary trials to assess the ability of plant species to extract metals are presented. A range of zinc and nickel hyperaccumulator plants from the Brassicaceae family, collected from diverse populations in Europe, were grown on plots along with nonaccumulating crop plants from the same family. Extraction efficiencies and the number of croppings required to reduce the total zinc in the soil to a concentration of 300 mg/kg are tabulated. Zinc accumulation remained high over a wide range of soil metal concentration. However, the concentration of nickel in the hyperaccumulators increased in accordance with increasing total nickel concentrations in the soil. Calculations suggest that there is an excellent potential for using hyperaccumulator species to remove metals from the rhizosphere where remediation can be considered over a period of years and multiple cropping is a viable option.

  18. Regulation of gemma formation in the copper moss Scopelophila cataractae by environmental copper concentrations.

    PubMed

    Nomura, Toshihisa; Hasezawa, Seiichiro

    2011-09-01

    Considerable attention has recently been focused on the use of hyperaccumulator plants for the phytoremediation of soils contaminated with heavy metals. The moss, Scopelophila cataractae (Mitt.) Broth., is a typical hyperaccumulator that is usually observed only in copper-rich environments and which accumulates high concentrations of copper in its tissues. However, many of the physiological processes and mechanisms for metal hyperaccumulation in S. cataractae remain unknown. To address this issue, we examined the mechanisms regulating gemma formation, which is considered the main strategy by which S. cataractae relocates to new copper-rich areas. From this study we found that treatment of S. cataractae with high concentrations of copper suppressed gemma formation but promoted protonemal growth. The suppressive effect was not observed by treatment with heavy metals other than copper. These results suggest the importance of copper-sensitive asexual reproduction in the unique life strategy of the copper moss, S. cataractae. PMID:21082328

  19. Characterization of selenium and sulfur accumulation across the genus Stanleya (Brassicaceae): A field survey and common-garden experiment.

    PubMed

    Cappa, Jennifer J; Cappa, Patrick J; El Mehdawi, Ali F; McAleer, Jenna M; Simmons, Mark P; Pilon-Smits, Elizabeth A H

    2014-04-21

    Premise of study: Selenium (Se) hyperaccumulation, the capacity to concentrate the toxic element Se above 1000 mgkg(-1)dry mass, is found in relatively few taxa native to seleniferous soils. While Se hyperaccumulation has been shown to likely be an adaptation that protects plants from herbivory, its evolutionary history remains unstudied. Stanleya (Brassicaceae) is a small genus comprising seven species endemic to the western United States. Stanleya pinnata is a hyperaccumulator of selenium (Se). In this study we investigated to what extent other Stanleya taxa accumulate Se both in the field and a greenhouse setting on seleniferous soil. Methods: We collected multiple populations of six of the seven species and all four varieties of S. pinnata. We tested leaves, fruit, and soil for in situ Se and sulfur (S) concentrations. The seeds collected in the field were used for a common garden study in a greenhouse. Key results: We found that S. pinnata var. pinnata is the only hyperaccumulator of Se. Within S. pinnata var. pinnata, we found a geographic pattern related to Se hyperaccumulation where the highest accumulating populations are found on the eastern side of the continental divide. We also found differences in genome size within the S. pinnata species complex. Conclusions: The S. pinnata species complex has a range of physiological properties making it an attractive system to study the evolution of Se hyperaccumulation. Beyond the basic scientific value of understanding the evolution of this fascinating trait, we can potentially use S. pinnata or its genes for environmental cleanup and/or nutrient-enhanced dietary material. PMID:24752889

  20. Replication and encapsidation of the viroid-like satellite RNA of lucerne transient streak virus are supported in divergent hosts by cocksfoot mottle virus and turnip rosette virus.

    PubMed

    Sehgal, O P; Sinha, R C; Gellatly, D L; Ivanov, I; AbouHaidar, M G

    1993-04-01

    Cocksfoot mottle sobemovirus supports replication and encapsidation of the viroid-like satellite RNA (sat-RNA) of lucerne transient streak virus (LTSV) in two monocotyledonous species, Triticum aestivum and Dactylis glomerata. Additionally, LTSV sat-RNA replicates effectively in the presence of turnip rosette sobemovirus in Brassica rapa, Raphanus raphanistrum and Sinapsis arvensis, but not in Thlaspi arvense or Nicotiana bigelovii, indicating that host species markedly influence this interaction. Previous reports of the association between LTSV sat-RNA and helper sobemoviruses were limited to dicotyledonous hosts. Our results demonstrate that the biological interaction between these two entities spans divergent dicotyledonous and monocotyledonous species. PMID:7682254

  1. 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.

  2. Histidine promotes the loading of nickel and zinc, but not of cadmium, into the xylem in Noccaea caerulescens

    PubMed Central

    Kozhevnikova, Anna D; Seregin, Ilya V; Verweij, Rudo; Schat, Henk

    2014-01-01

    Histidine is known to be involved in Ni hyperaccumulation. Recently, histidine-dependent xylem loading of Ni and Zn has been demonstrated in the Zn/Ni/Cd hyperaccumulator, Noccaea caerulescens. Here we tested the hypothesis whether Cd xylem loading is histidine-dependent, too. In contrast to that of Ni and Zn, the xylem loading of Cd was not affected by exogenous histidine. Histidine accumulation in root cells appears to facilitate the radial transport of Ni and Zn, but not Cd, across the roots. This may be due to the relatively high preference of Cd for coordination with sulfur over coordination with nitrogen, in comparison with Ni and Zn. PMID:25763695

  3. 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

  4. Selenium Accumulation in Flowers and its Effects on Pollination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selenium, both an essential micronutrient and a potential toxin, is hyperaccumulated by some plants up to 1% of dry weight. The functional significance of this rare phenomenon may be an elemental defense against herbivores and pathogens. In this first of its kind study, we investigate Se distributio...

  5. Draft Genome Sequence of Stenotrophomonas maltophilia SeITE02, a Gammaproteobacterium Isolated from Selenite-Contaminated Mining Soil

    PubMed Central

    Bertolini, Cristina; van Aerle, Ronny; Lampis, Silvia; Moore, Karen A.; Paszkiewicz, Konrad; Butler, Clive S.

    2014-01-01

    Stenotrophomonas maltophilia strain SeITE02 was isolated from the rhizosphere of the selenium-hyperaccumulating legume Astragalus bisculcatus. In this report, we provide the 4.56-Mb draft genome sequence of S.maltophilia SeITE02, a gammaproteobacterium that can withstand high concentrations of selenite and reduce these to elemental selenium. PMID:24812214

  6. 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...

  7. 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...

  8. Root-Secreted Nicotianamine from Arabidopsis halleri Facilitates Zinc Hypertolerance by Regulating Zinc Bioavailability1[W][OPEN

    PubMed Central

    Tsednee, Munkhtsetseg; Yang, Shun-Chung; Lee, Der-Chuen; Yeh, Kuo-Chen

    2014-01-01

    Hyperaccumulators tolerate and accumulate extraordinarily high concentrations of heavy metals. Content of the metal chelator nicotianamine (NA) in the root of zinc hyperaccumulator Arabidopsis halleri is elevated compared with nonhyperaccumulators, a trait that is considered to be one of the markers of a hyperaccumulator. Using metabolite-profiling analysis of root secretions, we found that excess zinc treatment induced secretion of NA in A. halleri roots compared with the nonhyperaccumulator Arabidopsis thaliana. Metal speciation analysis further revealed that the secreted NA forms a stable complex with Zn(II). Supplying NA to a nonhyperaccumulator species markedly increased plant zinc tolerance by decreasing zinc uptake. Therefore, NA secretion from A. halleri roots facilitates zinc hypertolerance through forming a Zn(II)-NA complex outside the roots to achieve a coordinated zinc uptake rate into roots. Secretion of NA was also found to be responsible for the maintenance of iron homeostasis under excess zinc. Together our results reveal root-secretion mechanisms associated with hypertolerance and hyperaccumulation. PMID:25118254

  9. What about the rare-earth elements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is insufficient understanding of the nutritional physiology of pecan trees and orchards; thus, affecting nutmeat yield and quality, disease resistance and alternate bearing. An analysis of the rare-earth element composition of pecan and related hickory cousins found that they hyperaccumulate ...

  10. 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...

  11. Identification of a novel pathway involving a GATA transcription factor in yeast and possibly plant Zn uptake and homeostasis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To gain a better understanding of the regulation of Zn homeostasis in plants and the degree of conservation of Zn homeostasis between plants and yeast, a cDNA library from the Zn/Cd hyperaccumulating plant species, Nocceae caerulescens, was screened for its ability to restore growth under Zn limitin...

  12. 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...

  13. 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...

  14. 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...

  15. 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 ...

  16. 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...

  17. 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.

  18. 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...

  19. 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) ...

  20. Wounding of Arabidopsis halleri leaves enhances cadmium accumulation that acts as a defense against herbivory.

    PubMed

    Plaza, Sonia; Weber, Johann; Pajonk, Simone; Thomas, Jrme; Talke, Ina N; Schellenberg, Maja; Pradervand, Sylvain; Burla, Bo; Geisler, Markus; Martinoia, Enrico; Krmer, Ute

    2015-06-01

    Approximately 0.2% of all angiosperms are classified as metal hyperaccumulators based on their extraordinarily high leaf metal contents, for example >1% zinc, >0.1% nickel or >0.01% cadmium (Cd) in dry biomass. So far, metal hyperaccumulation has been considered to be a taxon-wide, constitutively expressed trait, the extent of which depends solely on available metal concentrations in the soil. Here we show that in the facultative metallophyte Arabidopsis halleri, both insect herbivory and mechanical wounding of leaves trigger an increase specifically in leaf Cd accumulation. Moreover, the Cd concentrations accumulated in leaves can serve as an elemental defense against herbivory by larvae of the Brassicaceae specialist small white (Pieris rapae), thus allowing the plant to take advantage of this non-essential trace element and toxin. Metal homeostasis genes are overrepresented in the systemic transcriptional response of roots to the wounding of leaves in A. halleri, supporting that leaf Cd accumulation is preceded by systemic signaling events. A similar, but quantitatively less pronounced transcriptional response was observed in A. thaliana, suggesting that the systemically regulated modulation of metal homeostasis in response to leaf wounding also occurs in non-hyperaccumulator plants. This is the first report of an environmental stimulus influencing metal hyperaccumulation. PMID:25753945

  1. Effects of arsenic species and concentrations on arsenic accumulation by different fern species in a hydroponic system.

    PubMed

    Fayiga, A O; Ma, L Q; Santos, Jorge; Rathinasabapathi, B; Stamps, B; Littell, R C

    2005-01-01

    Two hydroponic experiments were conducted to evaluate factors affecting plant arsenic (As) hyperaccumulation. In the first experiment; two As hyperaccumulators (Pteris vittata and P. cretica mayii) were exposed to 1 and 10 mg L(-1) arsenite (AsIII) and monomethyl arsenic acid (MMA) for 4 wk. Total As concentrations in plants (fronds and roots) and solution were determined In the second experiment P. vittata and Nephrolepis exaltata (a non-As hyperaccumulator) were exposed to 5 mgL(-1) arsenate (AsV) and 20 mgL(-1) AsIIIfor 1 and 15 d. Total As and AsIII concentrations in plants were determined Compared to P. cretica mayii, P. vittata was more efficient in arsenic accumulation (1075-1666 vs. 249-627mg kg(-1) As in the fronds) partially because it is more efficient in As translocation. As translocation factor (As concentration ratio in fronds to roots) was 3.0-5.6 for P. vittata compared to 0.1 to 4.8 for P. cretica. Compared to N. exaltata, P. vittata was significantly more efficient in arsenic accumulation (38-542 vs. 4.8-71 mg kg(-1) As in thefronds) as well asAs translocation (1.3-5.6 vs. 0.2-0.5). In addition, P. vittata was much more efficient in As reduction from AsV to AsIII (83-84 vs. 13-24% AsIII in the fronds). Little As reduction occurred after 1-d exposure to AsV in both species indicates that As reduction was not instantaneous even in an As hyperaccumulator. Our data were consistent with the hypothesis that both As translocation and As reduction are important for plant As hyperaccumulation. PMID:16285413

  2. 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

  3. 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.

  4. 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.

  5. Shining light on metals in the environment

    SciTech Connect

    McNear, Jr., D.H.; Tappero, R.; Sparks, D.L.

    2010-07-20

    Elucidating the speciation of heavy metals in the environment is paramount to understanding their potential mobility and bioavailability. Cutting-edge synchrotron-based techniques such as microfocused X-ray absorption fine-structure (XAFS) and X-ray fluorescence (XRF) spectroscopy and microtomography have revolutionized the way metal reactions and processes in natural systems are studied. In this article, we apply these intense-light tools to decipher metal forms (species) and associations in contaminated soils and metal-hyperaccumulating plants.

  6. Use of synchrotron radiation to characterize metals in plants: the case of Cd in the hyperacumulator Arabidopsis halleri

    NASA Astrophysics Data System (ADS)

    Isaure, M.; Sarret, G.; Verbruggen, N.

    2010-12-01

    Phytoremediation uses plants to extract (phytoextraction) or stabilize (phytostabilization) metals accumulated in soils, and can be an alternative to invasive physico-chemical remediation techniques. Its development requires the knowledge of the mechanisms involved in metal tolerance and accumulation in plants, and particularly the way that plants transfer and store metals. In that context, synchrotron radiation based techniques such as micro-focused X-Ray Fluorescence (µXRF), and micro-focused X-ray Absorption Spectroscopy, including Extended X-ray Absorption Fine Structure and X-ray Absorption Near Edge Structure, are particularly suited to determine the localization and the chemical forms of metals in the different tissues, cells and sub-cellular compartments. Arabidopsis halleri is a Zn, Cd hyperaccumulating plant, naturally growing on contaminated sites, and is a model plant to investigate metal hyperaccumulation. This work presents the application of µXRF and Cd µXANES to determine the distribution and speciation of Cd in this species. Results showed that Cd was mainly located in the mesophyll and veins of leaves. It is bound to S ligands in some leaves and to O/N ligands in other ones, and the observed variations may be related to the age of the leaves. Cd speciation seems to differ from other metals, and particularly Zn, generally encountered in hyperaccumulators. High local Cd concentrations were also detected at the base of trichomes, epidermal hairs of leaves, associated to O/N ligands, probably to the cell wall. This phenomenon was also observed on non-hyperaccumulators and is clearly not the major sink for Cd, but trichomes might play a role in the detoxification process. This study illustrates the suitability of synchrotron radiation based techniques to investigate metal distribution and speciation in plants.

  7. Analysis of sulfur and selenium assimilation in Astragalus plants with varying capacities to accumulate selenium.

    PubMed

    Sors, Thomas G; Ellis, Danielle R; Na, Gun Nam; Lahner, Brett; Lee, Sangman; Leustek, Thomas; Pickering, Ingrid J; Salt, David E

    2005-06-01

    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. PMID:15941393

  8. Lithium, Vanadium and Chromium Uptake Ability of Brassica juncea from Lithium Mine Tailings.

    PubMed

    Elektorowicz, M; Keropian, Z

    2015-01-01

    The potential for phytoremediation and phytostabilization of lithium in lieu with vanadium and chromium on a formulated acidic heterogeneous growth media engineered around lithium mine tailings, was investigated in four phases: (1) overall efficiency of the removal of the three metals, (2) bioaccumulation ratios of the three metals, (3) overall relative growth rate, and (4) translocation index of the three metals in the physiology of the hyperaccumulator plant. A pot study was conducted to assess the suitability of Brassica juncea (Indian mustard) in a phytoremediation process whereby it was lingered for eighty-six days under homogeneous growth conditions and irrigated bidaily with organic fertilizer amended with LiCl. A post harvest data analysis was achieved through ashing and the implementation of cold digestion procedure in a concentrated hydrochloric acidic matrix. In physiological efficiency parameters, the hyperaccumulator plant was twice as able to phytostabilize chromium and four times was able to phytostabilize vanadium in comparison to lithium. Moreover, it was extremely efficient in translocating and accumulating lithium inside its upper physiological sites, more so than chromium and vanadium, thereby demonstrating Indian mustard, as a hyperaccumulator plant, for phytoextraction and phytostabilization in an acidic heterogeneous rhizosphere, with an extremely low relative growth rate. PMID:25747238

  9. Cd and Zn accumulation in plants from the Padaeng zinc mine area.

    PubMed

    Phaenark, C; Pokethitiyook, P; Kruatrachue, M; Ngernsansaruay, C

    2009-07-01

    Significant cadmium (Cd) contamination In soil and rice has been discovered in Mae Sot, Tak province, Thailand where the rice-based agricultural systems are established in the vicinity of a zinc mine. The prolonged consumption of Cd contaminated rice has potential risks to public health and health impacts of Cd exposed populations in Mae Sot have been demonstrated. The Thai government has prohibited rice cultivation in the area as an effort to prevent further exposure. Phytoextraction, the use of plants to remove contaminants from soil, is a potential option to manage Cd-contaminated areas. However, successful phytoextraction depends on first identifying effective hyperaccumulator plants appropriate for local climatic conditions. Five sampling sites at Padaeng Zinc mine, Tak province were selected to collect plant and soil samples. Total Cd and Zn concentrations in sediments or soils were approximately 596 and 20,673 mg kg(-1) in tailing pond area, 543 and 20,272 mg kg(-1) in open pit area, 894 and 31,319 mg kg(-1) in stockpile area, 1458 and 57,012 mg kg(-1) in forest area and 64 and 2733 mg kg(-1) in Cd contaminated rice field. Among a total of 36 plant species from 16 families, four species (Chromolaena odoratum, Gynura pseudochina, Impatiens violaeflora and Justicia procumbens) could be considered as Cd hyperaccumulators since their shoot Cd concentrations exceeded 100 mg Cd kg(-1) dry mass and they showed a translocation factor >1. Only Justicia procumbens could be considered as a Zn hyperaccumulator (Zn concentration in its shoot more than 10,000 mg Zn kg(-1) dry mass with the translocation factor >1). PMID:19810350

  10. Nickel accumulation by Streptanthus polygaloides (Brassicaceae) reduces floral visitation rate.

    PubMed

    Meindl, George A; Ashman, Tia-Lynn

    2014-02-01

    Hyperaccumulation is the phenomenon whereby plants take up and sequester in high concentrations elements that generally are excluded from above-ground tissues. It largely is unknown whether the metals taken up by these plants are transferred to floral rewards (i.e., nectar and pollen) and, if so, whether floral visitation is affected. We grew Streptanthus polygaloides, a nickel (Ni) hyperaccumulator, in short-term Ni supplemented soils and control soils to determine whether Ni is accumulated in floral rewards and whether floral visitation is affected by growth in Ni-rich soils. We found that while supplementation of soils with Ni did not alter floral morphology or reward quantity (i.e., anther size or nectar volume), Ni did accumulate in the nectar and pollen-filled anthers-providing the first demonstration that Ni is accumulated in pollinator rewards. Further, S. polygaloides grown in Ni-supplemented soils received fewer visits per flower per hour from both bees and flies (both nave to Ni-rich floral resources in the study area) relative to plants grown in control soils, although the probability a plant was visited initially was unaffected by Ni treatment. Our findings show that while Ni-rich floral rewards decrease floral visitation, floral visitors are not completely deterred, so some floral visitors may collect and ingest potentially toxic resources from metal-hyperaccumulating plants. In addition to broadening our understanding of the effects of metal accumulation on ecological interactions in natural populations, these results have implications for the use of insect-pollinated plants in phytoremediation. PMID:24477333

  11. Biotechnological applications of serpentine soil bacteria for phytoremediation of trace metals.

    PubMed

    Rajkumar, Mani; Vara Prasad, Majeti Narasimha; Freitas, Helena; Ae, Noriharu

    2009-01-01

    Serpentine or ultramafic soils are produced by weathering and pedogenesis of ultramafic rocks that are characterized by high levels of Ni, Cr, and sometimes Co, but contain low levels of essential nutrients such as N, P, K, and Ca. A number of plant species endemic to serpentine soils are capable of accumulating exceptionally high concentrations of Ni, Zn, and Co. These plants are known as metal "hyperaccumulators." The function of hyperaccumulation depends not only on the plant, but also on the interaction of the plant roots with rhizosphere microbes and the concentrations of bioavailable metals in the soil. The rhizosphere provides a complex and dynamic microenvironment where microorganisms, in association with roots, form unique communities that have considerable potential for the detoxification of hazardous materials. The rhizosphere bacteria play a significant role on plant growth in serpentine soils by various mechanisms, namely, fixation of atmospheric nitrogen, utilization of 1-aminocyclopropane-1-carboxylic acid (ACC) as the sole N source, production of siderophores, or production of plant growth regulators (hormones). Further, many microorganisms in serpentine soil are able to solubilize "unavailable" forms of heavy metal-bearing minerals by excreting organic acids. In addition, the metal-resistant serpentine isolates increase the efficiency of phytoextraction directly by enhancing the metal accumulation in plant tissues and indirectly by promoting the shoot and root biomass of hyperaccumulators. Hence, isolation of the indigenous and stress-adapted beneficial bacteria serve as a potential biotechnological tool for inoculation of plants for the successful restoration of metal-contaminated ecosystems. In this study, we highlight the diversity and beneficial features of serpentine bacteria and discuss their potential in phytoremediation of serpentine and anthropogenically metal-contaminated soils. PMID:19514893

  12. Small RNA and degradome sequencing reveals important microRNA function in Astragalus chrysochlorus response to selenium stimuli.

    PubMed

    Cakir, Ozgur; Candar-Cakir, Bilgin; Zhang, Baohong

    2016-02-01

    Selenium (Se), an essential element, plays important roles in human health as well as environmental sustainability. Se hyperaccumulating plants are thought as an alternative selenium resource, recently. Astragalus species are known as hyperaccumulator of Se by converting it to nonaminoacid compounds. However, Se-metabolism-related hyperaccumulation is not elucidated in plants yet. MicroRNAs (miRNAs) are key molecules in many biological and metabolic processes via targeting mRNAs, which may also play an important role in Se accumulation in plants. In this study, we identified 418 known miRNAs, belonging to 380 families, and 151 novel miRNAs induced by Se exposure in Astragalus chyrsochlorus callus. Among known miRNAs, the expression of 287 families was common in both libraries, besides 71 families were expressed only in Se-treated sample, whereas 60 conserved families were expressed in control tissue. miR1507a, miR1869 and miR2867-3p were mostly up-regulated, whereas miR1507-5p and miR8781b were significantly down-regulated by Se exposure. Computational analysis shows that the targets of miRNAs are involved in different types of biological mechanisms including 47 types of cellular component, 103 types of molecular function and 144 types of biological process. Degradome analysis shows that 1256 mRNAs were targeted by 499 miRNAs. We conclude that some known and novel miRNAs such as miR167a, miR319, miR1507a, miR4346, miR7767-3p, miR7800, miR9748 and miR-n93 target transcription factors, disease resistance proteins and some specific genes like cysteine synthase and might be related to plant hormone signal transduction, plant-pathogen interaction and sulphur metabolism pathways. PMID:25998129

  13. Utilization of a Model for Uptake of Cadmium by Plants as a Phytoremediation Assessment Tool

    NASA Astrophysics Data System (ADS)

    Takahashi, M.; Furbish, D. J.; Clarke, J.

    2008-12-01

    Some traditional methods of environmental remediation, such as removal and disposal of contaminated soil, are loosing economic favor and public acceptance, while others, such as in situ phytoremediation, are being carefully examined because of their attractiveness as environmentally friendly, low-cost solutions to site clean-up. The success of phytoremediation strategies, however, hinges on the ability of selected plants, or plant communities, to effectively uptake, accumulate and tolerate targeted contaminants. Heavy metals, specifically cadmium (Cd), are not essential nutrients to plants. However, chemically similar zinc (Zn) is a micronutrient and is actively taken up by hyperaccumulators. For this reason, the mechanisms involved in uptake of Cd parallel those of Zn. Ideally, Cd would be allocated to the stem, leaf, and/or flower, where it becomes harvestable. Our modeling work simulates the uptake and the storage of Cd in a growing hyperaccumulator. After uptake, Cd is partitioned between adsorption to plant tissue and upward movement to leaves driven by transpiration. Uptake, adsorption and transport are also regulated by phytotoxicity. Simulations suggest that a young plant with small biomass can quickly reach phytotoxicity, which shuts down the normal operation of the plant. Conversely, mature plants on a mildly contaminated site, if harvested before the plants die due to phytotoxicity or natural cause, not only survive but may occasionally thrive. The immediate aim is to estimate the effectiveness and limitations of Cd uptake by hyperaccumulators. The eventual goal of this study is to expand the model in spatial and temporal scales, from individual plants to the community scale, and from one harvest interval to several generations. Understanding the interface between physical and biological processes, specifically the uptake and release of contaminants, provides scientists and engineers tools to assess whether phytoremediation is a reasonable strategy for a given environment.

  14. 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

  15. Cloning and characterization of the nicotianamine synthase gene in Eruca vesicaria subsp sativa.

    PubMed

    Huang, B L; Cheng, C; Zhang, G Y; Su, J J; Zhi, Y; Xu, S S; Cai, D T; Zhang, X K; Huang, B Q

    2015-01-01

    Nicotianamine (NA) is a ubiquitous metabolite in plants that bind heavy metals, is crucial for metal homeostasis, and is also an important metal chelator that facilitates long-distance metal transport and sequestration. NA synthesis is catalyzed by the enzyme nicotianamine synthase (NAS). Eruca vesicaria subsp sativa is highly tolerant to Ni, Pb, and Zn. In this study, a gene encoding EvNAS was cloned and characterized in E. vesicaria subsp sativa. The full-length EvNAS cDNA sequence contained a 111-bp 5'-untranslated region (UTR), a 155-bp 3'-UTR, and a 966-bp open reading frame encoding 322-amino acid residues. The EvNAS genomic sequence contained no introns, which is similar to previously reported NAS genes. The deduced translation of EvNAS contained a well-conserved NAS domain (1-279 amino acids) and an LIKI-CGEAEG box identical to some Brassica NAS and to the LIRL-box in most plant NAS, which is essential for DNA binding. Phylogenetic analysis indicated that EvNAS was most closely related to Brassica rapa NAS3 within the Cruciferae, followed by Thlaspi NAS1, Camelina NAS3, and Arabidopsis NAS3. A reverse transcription-polymerase chain reaction indicated that EvNAS expression was greatest in the leaves, followed by the flower buds and hypocotyls. EvNAS was moderately expressed in the roots. PMID:26782459

  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. Roles of plant metal tolerance proteins (MTP) in metal storage and potential use in biofortification strategies

    PubMed Central

    Ricachenevsky, Felipe K.; Menguer, Paloma K.; Sperotto, Raul A.; Williams, Lorraine E.; Fett, Janette P.

    2013-01-01

    Zinc (Zn) is an essential micronutrient for plants, playing catalytic or structural roles in enzymes, transcription factors, ribosomes, and membranes. In humans, Zn deficiency is the second most common mineral nutritional disorder, affecting around 30% of the world's population. People living in poverty usually have diets based on milled cereals, which contain low Zn concentrations. Biofortification of crops is an attractive cost-effective solution for low mineral dietary intake. In order to increase the amounts of bioavailable Zn in crop edible portions, it is necessary to understand how plants take up, distribute, and store Zn within their tissues, as well as to characterize potential candidate genes for biotechnological manipulation. The metal tolerance proteins (MTP) were described as metal efflux transporters from the cytoplasm, transporting mainly Zn2+ but also Mn2+, Fe2+, Cd2+, Co2+, and Ni2+. Substrate specificity appears to be conserved in phylogenetically related proteins. MTPs characterized so far in plants have a role in general Zn homeostasis and tolerance to Zn excess; in tolerance to excess Mn and also in the response to iron (Fe) deficiency. More recently, the first MTPs in crop species have been functionally characterized. In Zn hyperaccumulator plants, the MTP1 protein is related to hypertolerance to elevated Zn concentrations. Here, we review the current knowledge on this protein family, as well as biochemical functions and physiological roles of MTP transporters in Zn hyperaccumulators and non-accumulators. The potential applications of MTP transporters in biofortification efforts are discussed. PMID:23717323

  19. Uptake of metals and metalloids by plants growing in a lead-zinc mine area, Northern Vietnam.

    PubMed

    Nguyen, Thi Hoang Ha; Sakakibara, Masayuki; Sano, Sakae; Mai, Trong Nhuan

    2011-02-28

    This study was conducted to evaluate the phytoremediation and phytomining potential of 10 plant species growing naturally at one of the largest lead-zinc mines in Northern Vietnam. Total concentrations of heavy metals and arsenic were determined in the plant and in associated soil and water in and outside of the mine area. The results indicate that hyperaccumulation levels (mg kg(-1) dry weight) were obtained in Houttuynia cordata Thunb. (1140) and Pteris vittata L. (3750) for arsenic, and in Ageratum houstonianum Mill. (1130), Potamogeton oxyphyllus Miq. (4210), and P. vittata (1020) for lead. To the best of our knowledge, the present paper is the first report on metal accumulation and hyperaccumulation by H. cordata, A. houstonianum, and P. oxyphyllus. Based on the obtained concentrations of metals, bioconcentration and translocation factors, as well as the biomass of these plants, the two latter species and P. vittata are good candidates for phytoremediation of sites contaminated with arsenic and multi-metals. None of the collected plants was suitable for phytomining, given their low concentrations of useful metals (e.g., silver, gallium, and indium). PMID:21227580

  20. Accumulation of cadmium and zinc in Evodiopanax innovans.

    PubMed

    Takenaka, Chisato; Kobayashi, Motoharu; Kanaya, Shotaro

    2009-12-01

    The use of tree species for phytoremediation of contaminated soil offers the advantage of a large biomass in which to store contaminants. We investigated the cadmium (Cd) and zinc (Zn) accumulation ability of Evodiopanax innovans, a common deciduous tree species belonging to the Araliaceae family and widely found in secondary forests in Japan. Sampling was conducted at an old silver mine. Leaf samples were collected from nine tree species, including E. innovans. The seasonal variation of metal concentrations in the leaves and the detailed distribution of metals in the leaves and twigs of E. innovans were measured. We also analyzed the contents of organic acids in the leaves. The highest concentration of Cd in the leaves of E. innovans was 118 ?g/g, which exceeds the threshold level for being considered a Cd hyperaccumulator (100 ?g/g). For Zn, the highest value was 1040 ?g/g in leaves, which is less than required to qualify as a Zn hyperaccumulator. Both Cd and Zn were found to accumulate in the petioles and veins of leaves and the bark of twigs. Since the oxalic acid content of leaves showed a weak correlation with Cd concentration, oxalic acid may play an important role in the accumulation of Cd. Taking both the Cd concentration level and the biomass of this woody plant into consideration, it may be possible to use E. innovans for the phytoremediation of Cd-contaminated soils. PMID:18850317

  1. Effects of selenium accumulation on reproductive functions in Brassica juncea and Stanleya pinnata

    PubMed Central

    Prins, Christine N.; Hantzis, Laura J.; Quinn, Colin F.; Pilon-Smits, Elizabeth A. H.

    2011-01-01

    Selenium (Se) is an essential micronutrient for many organisms, but is also a toxin and environmental pollutant at elevated levels. Due to its chemical similarity to sulphur, most plants readily take up and assimilate Se. Se accumulators such as Brassica juncea can accumulate Se between 0.01% and 0.1% of dry weight (DW), and Se hyperaccumulators such as Stanleya pinnata (Brassicaeae) contain between 0.1% and 1.5% DW of Se. While Se accumulation offers the plant a variety of ecological benefits, particularly protection from herbivory, its potential costs are still unexplored. This study examines the effects of plant Se levels on reproductive functions. In B. juncea, Se concentrations >0.050.1% caused decreases in biomass, pollen germination, individual seed and total seed weight, number of seeds produced, and seed germination. In S. pinnata there was no negative effect of increased Se concentration on pollen germination. In cross-pollination of B. juncea plants with different Se levels, both the maternal and paternal Se level affected reproduction, but the maternal Se concentration had the most pronounced effect. Interestingly, high-Se maternal plants were most efficiently pollinated by Se-treated paternal plants. These data provide novel insights into the potential reproductive costs of Se accumulation, interactive effects of Se in pollen grains and in the pistil, and the apparent evolution of physiological tolerance mechanisms in hyperaccumulators to avoid reproductive repercussions. PMID:21841173

  2. Effect of zinc and glucosinolates on nutritional quality of Noccaea caerulescens and infestation by Aleyrodes proletella.

    PubMed

    Asad, Saeed Ahmad; Young, Scott D; West, Helen M

    2015-04-01

    The Zn hyperaccumulating plant, Noccaea caerulescens, was grown under controlled conditions at a range of Zn concentrations (0-1000 mg kg(-1) dwt. soil) to determine the effectiveness of hyperaccumulation in deterring the cabbage whitefly, Aleyrodes proletella, and to establish the relationship between levels of foliar Zn and glucosinolates (organic defence compounds). Two weeks after introducing A. proletella adults to the plants, next generation nymphs were quantified. This sucking insect caused minimal damage to plant tissue and did not affect foliar glucosinolate levels. Foliar Zn concentrations increased with increasing soil Zn application and reached a maximum of ~7000 mg kg(-1). More whitefly nymphs were observed on plants as the foliar Zn concentration increased (up to ~3000 mg kg(-1)) after which numbers declined. Zn was an explanatory variable in accumulated generalised linear regression after the variation in the data due to C/N ratio had been accounted for. Nymph numbers declined with increasing C/N ratio and increased with increasing N concentration. The highest glucosinolate concentrations were in shoots with the lowest Zn concentrations; this is consistent with the 'trade-off' hypothesis which states that elemental defence mechanisms allow for lowered organic defences. PMID:25525711

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

    PubMed

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

    2015-07-01

    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

  4. Phenotypic and molecular consequences of overexpression of metal-homeostasis genes

    PubMed Central

    Antosiewicz, Danuta M.; Barabasz, Anna; Siemianowski, Oskar

    2014-01-01

    Metal hyperaccumulating plants are able to store very large amounts of metals in their shoots. There are a number of reasons why it is important to be able to introduce metal hyperaccumulation traits into non-accumulating species (e.g., phytoremediation or biofortification in minerals) and to engineer a desired level of accumulation and distribution of metals. Metal homeostasis genes have therefore been used for these purposes. Engineered accumulation levels, however, have often been far from expected, and transgenic plants frequently display phenotypic features not related to the physiological function of the introduced gene. In this review, we focus on an aspect often neglected in research on plants expressing metal homeostasis genes: the specific regulation of endogenous metal homeostasis genes of the host plant in response to the transgene-induced imbalance of the metal status. These modifications constitute one of the major mechanisms involved in the generation of the plant's phenotype, including unexpected characteristics. Interestingly, activation of so-called metal cross-homeostasis has emerged as a factor of primary importance. PMID:24639682

  5. Selenium accumulation in flowers and its effects on pollination.

    PubMed

    Quinn, Colin F; Prins, Christine N; Freeman, John L; Gross, Amanda M; Hantzis, Laura J; Reynolds, Ray J B; Yang, Soo in; Covey, Paul A; Bauelos, Gary S; Pickering, Ingrid J; Fakra, Sirine C; Marcus, Matthew A; Arathi, H S; Pilon-Smits, Elizabeth A H

    2011-11-01

    Selenium (Se) hyperaccumulation has a profound effect on plant-arthropod interactions. Here, we investigated floral Se distribution and speciation in flowers and the effects of floral Se on pollen quality and plant-pollinator interactions. Floral Se distribution and speciation were compared in Stanleya pinnata, an Se hyperaccumulator, and Brassica juncea, a comparable nonhyperaccumulator. Pollen germination was measured from plants grown with varying concentrations of Se and floral visitation was compared between plants with high and low Se. Stanleya pinnata preferentially allocated Se to flowers, as nontoxic methyl-selenocysteine (MeSeCys). Brassica juncea had higher Se concentrations in leaves than flowers, and a lower fraction of MeSeCys. For B. juncea, high floral Se concentration impaired pollen germination; in S. pinnata Se had no effect on pollen germination. Floral visitors collected from Se-rich S. pinnata contained up to 270 ?g g(-1), concentrations toxic to many herbivores. Indeed, floral visitors showed no visitation preference between high- and low-Se plants. Honey from seleniferous areas contained 0.4-1 ?g Se g(-1), concentrations that could provide human health benefits. This study is the first to shed light on the possible evolutionary cost, through decreased pollen germination in B. juncea, of Se accumulation and has implications for the management of seleniferous areas. PMID:21793829

  6. Effects of selenium accumulation on reproductive functions in Brassica juncea and Stanleya pinnata.

    PubMed

    Prins, Christine N; Hantzis, Laura J; Quinn, Colin F; Pilon-Smits, Elizabeth A H

    2011-11-01

    Selenium (Se) is an essential micronutrient for many organisms, but is also a toxin and environmental pollutant at elevated levels. Due to its chemical similarity to sulphur, most plants readily take up and assimilate Se. Se accumulators such as Brassica juncea can accumulate Se between 0.01% and 0.1% of dry weight (DW), and Se hyperaccumulators such as Stanleya pinnata (Brassicaeae) contain between 0.1% and 1.5% DW of Se. While Se accumulation offers the plant a variety of ecological benefits, particularly protection from herbivory, its potential costs are still unexplored. This study examines the effects of plant Se levels on reproductive functions. In B. juncea, Se concentrations >0.05-0.1% caused decreases in biomass, pollen germination, individual seed and total seed weight, number of seeds produced, and seed germination. In S. pinnata there was no negative effect of increased Se concentration on pollen germination. In cross-pollination of B. juncea plants with different Se levels, both the maternal and paternal Se level affected reproduction, but the maternal Se concentration had the most pronounced effect. Interestingly, high-Se maternal plants were most efficiently pollinated by Se-treated paternal plants. These data provide novel insights into the potential reproductive costs of Se accumulation, interactive effects of Se in pollen grains and in the pistil, and the apparent evolution of physiological tolerance mechanisms in hyperaccumulators to avoid reproductive repercussions. PMID:21841173

  7. 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.

  8. 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

  9. 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.

  10. Metabolic phenotypes of Saccharomyces cerevisiae mutants with altered trehalose 6-phosphate dynamics.

    PubMed

    Walther, Thomas; Mtimet, Narjes; Alkim, Ceren; Vax, Amlie; Loret, Marie-Odile; Ullah, Azmat; Gancedo, Carlos; Smits, Gertien J; Franois, Jean Marie

    2013-09-01

    In Saccharomyces cerevisiae, synthesis of T6P (trehalose 6-phosphate) is essential for growth on most fermentable carbon sources. In the present study, the metabolic response to glucose was analysed in mutants with different capacities to accumulate T6P. A mutant carrying a deletion in the T6P synthase encoding gene, TPS1, which had no measurable T6P, exhibited impaired ethanol production, showed diminished plasma membrane H?-ATPase activation, and became rapidly depleted of nearly all adenine nucleotides which were irreversibly converted into inosine. Deletion of the AMP deaminase encoding gene, AMD1, in the tps1 strain prevented inosine formation, but did not rescue energy balance or growth on glucose. Neither the 90%-reduced T6P content observed in a tps1 mutant expressing the Tps1 protein from Yarrowia lipolytica, nor the hyperaccumulation of T6P in the tps2 mutant had significant effects on fermentation rates, growth on fermentable carbon sources or plasma membrane H?-ATPase activation. However, intracellular metabolite dynamics and pH homoeostasis were strongly affected by changes in T6P concentrations. Hyperaccumulation of T6P in the tps2 mutant caused an increase in cytosolic pH and strongly reduced growth rates on non-fermentable carbon sources, emphasizing the crucial role of the trehalose pathway in the regulation of respiratory and fermentative metabolism. PMID:23763276

  11. Chemically Induced Conditional Rescue of the Reduced Epidermal Fluorescence8 Mutant of Arabidopsis Reveals Rapid Restoration of Growth and Selective Turnover of Secondary Metabolite Pools1[C][OPEN

    PubMed Central

    Kim, Jeong Im; Ciesielski, Peter N.; Donohoe, Bryon S.; Chapple, Clint; Li, Xu

    2014-01-01

    The phenylpropanoid pathway is responsible for the biosynthesis of diverse and important secondary metabolites including lignin and flavonoids. The reduced epidermal fluorescence8 (ref8) mutant of Arabidopsis (Arabidopsis thaliana), which is defective in a lignin biosynthetic enzyme p-coumaroyl shikimate 3′-hydroxylase (C3′H), exhibits severe dwarfism and sterility. To better understand the impact of perturbation of phenylpropanoid metabolism on plant growth, we generated a chemically inducible C3′H expression construct and transformed it into the ref8 mutant. Application of dexamethasone to these plants greatly alleviates the dwarfism and sterility and substantially reverses the biochemical phenotypes of ref8 plants, including the reduction of lignin content and hyperaccumulation of flavonoids and p-coumarate esters. Induction of C3′H expression at different developmental stages has distinct impacts on plant growth. Although early induction effectively restored the elongation of primary inflorescence stem, application to 7-week-old plants enabled them to produce new rosette inflorescence stems. Examination of hypocotyls of these plants revealed normal vasculature in the newly formed secondary xylem, presumably restoring water transport in the mutant. The ref8 mutant accumulates higher levels of salicylic acid than the wild type, but depletion of this compound in ref8 did not relieve the mutant’s growth defects, suggesting that the hyperaccumulation of salicylic acid is unlikely to be responsible for dwarfism in this mutant. PMID:24381065

  12. 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

  13. 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, Ccile; Carnol, Monique; Bosman, Bernard; Krmer, 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

  14. Variation in arsenic, lead and zinc tolerance and accumulation in six populations of Pteris vittata L. from China.

    PubMed

    Wu, F Y; Leung, H M; Wu, S C; Ye, Z H; Wong, M H

    2009-01-01

    Arsenic, Pb and Zn tolerance and accumulation were investigated in six populations of Pteris vittata collected from As-contaminated and uncontaminated sites in southeast China compared with Pteris semipinnata (a non-As hyperaccumulator) in hydroponics and on As-contaminated soils. The results showed that both metallicolous and nonmetallicolous population of P. vittata possessed high-level As tolerance, and that the former exhibited higher As tolerance (but not Pb and Zn tolerance) than the latter. In hydroponic culture, nonmetallicolous population clearly showed significantly higher As concentrations in fronds than those in metallicolous populations. In pot trials, As concentrations in fronds of nonmetallicolous population ranged from 1060 to 1639 mg kg(-1), about 2.6- to 5.4-folds as those in metallicolous populations. It was concluded that As tolerance in P. vittata resulted from both constitutive and adaptive traits, Pb and Zn tolerances were constitutive properties, and that nonmetallicolous population possesses more effective As hyperaccumulation than metallicolous populations. PMID:19371990

  15. Candidate gene analysis of organ pigmentation loci in the Solanaceae

    PubMed Central

    Thorup, T. A.; Tanyolac, B.; Livingstone, K. D.; Popovsky, S.; Paran, I.; Jahn, Molly

    2000-01-01

    Ten structural genes from the Capsicum (pepper) carotenoid biosynthetic pathway have been localized on a (Capsicum annuum Capsicum chinense)F2 genetic map anchored in Lycopersicon (tomato). The positions of these genes were compared with positions of the same genes in tomato when known, and with loci from pepper, potato, and tomato that affect carotenoid levels in different tissues. C2, one of three phenotypically defined loci determining pepper fruit color, cosegregated with phytoene synthase. The capsanthincapsorubin synthase (Ccs) locus, shown previously to cosegregate with Y, another pepper fruit color locus, mapped to pepper chromosome 6. Other structural genes in pepper corresponded to loci affecting carotenoid production as follows: Ccs in pepper and the B locus for hyperaccumulation of ?-carotene in tomato fruit mapped to homeologous regions; the position of the lycopene ?-cyclase gene in pepper may correspond to the lutescent-2 mutation in tomato; and the lycopene ?-cyclase locus in pepper corresponded to the lycopene ?-cyclase locus/Del mutation for hyperaccumulation of ?-carotene in tomato fruit. Additional associations were seen between the structural genes and previously mapped loci controlling quantitative variation in pepper and tomato fruit color. These results demonstrate that comparative analyses using candidate genes may be used to link specific metabolic phenotypes and loci that affect these phenotypes in related species. PMID:11027328

  16. Constitutive camalexin production and environmental stress response variation in Arabidopsis populations from the Iberian Peninsula.

    PubMed

    Zhang, Nana; Lariviere, Andy; Tonsor, Stephen J; Traw, M Brian

    2014-08-01

    Optimal defense theory predicts that induction of defensive secondary metabolites in plants will be inversely correlated with constitutive expression of those compounds. Here, we asked whether camalexin, an important defense against fungal and bacterial pathogens, support this prediction in structured natural populations of Arabidopsis thaliana from the Iberian Peninsula. In common garden experiments, we found that genotypes from the VIE population constitutively hyper-accumulated camalexin. Camalexin concentrations were not induced significantly when plants were exposed to a temperature of 10C for 48h. However, they were induced when plants were exposed to 48h of infection by the virulent bacterial pathogen, Pseudomonas syringae pv. tomato DC3000. Genotypes from the VIE population with the hyper-accumulation of camalexin were significantly more resistant to bacterial growth. Induction of camalexin was negatively correlated with constitutive camalexin concentrations following log transformation and two different corrections for autocorrelation, thus supporting the tradeoff predicted by optimal defense theory. Constitutive overexpression of camalexin was not explained by the only known natural genetic polymorphism at the Accelerated Cell Death 6, ACD6, locus. Collectively, the results support an important role of camalexin in defense against P. syringae as well as significant structured variation in defense levels within wild populations. PMID:25017162

  17. Manganese accumulation in the leaf mesophyll of four tree species: a PIXE/EDAX localization study.

    PubMed

    Fernando, D R; Bakkaus, E J; Perrier, N; Baker, A J M; Woodrow, I E; Batianoff, G N; Collins, R N

    2006-01-01

    Little is known about the spatial distribution of excess manganese (Mn) in the leaves of tolerant plants. Recently, the first such study of a Mn hyperaccumulator showed that the highest localized Mn concentrations occur in the photosynthetic tissue. This is in contrast to reports based on localization of foliar accumulation of other heavy metals. Here, four tree species, Gossia bidwillii, Virotia neurophylla, Macadamia integrifolia and Macadamia tetraphylla, which hyperaccumulate or strongly accumulate Mn, were studied. Cross-sectional foliar Mn localization was carried out in situ using proton-induced X-ray emission/energy dispersive X-ray analysis (PIXE/EDAX). All four species contained photosynthetic tissues with multiple palisade layers. These were shown to be the primary sequestration sites for Mn. Mn was not detected in the epidermal tissues. The findings of this study demonstrate a concurrence of three traits in four tree species, that is, accumulation of excess Mn in the leaves, its primary sequestration in the photosynthetic tissues, and multiple-layer palisade mesophyll. PMID:16918546

  18. Copper phytoremediation potential of Calandula officinalis L. and the role of antioxidant enzymes in metal tolerance.

    PubMed

    Goswami, Sunayana; Das, Suchismita

    2016-04-01

    Cu phytoremediation potential of an ornamental plant, Calandula officinalis, was explored in terms of growth responses, photosynthetic activities and antioxidant enzymes such as SOD, CAT and GPX. The results showed that this plant had high Cu tolerance of up to 400mg/kg, which is far above the phytotoxic range for non hyperaccumulators. It grew normally in soils at all the doses (150-400mg/kg) without showing external signs of phytotoxicity. At 150mg/kg, flowering was augmented; root and shoot biomass, root lengths and leaf soluble protein contents remained same as that of the control. However, chlorophyll and carotenoid pigment contents declined significantly along with significant elevations in lipid peroxidation, at all the doses. Elevations of antioxidant enzymes reflected stress as well as probable mitigation of reactive oxygen species due to Cu stress. Except for the highest conc. (400mg/kg), leaf accumulation of Cu was higher than root accumulations. The Cu accumulation peaked at 300mg/kg Cu in soil, with leaf and root accumulations to be respectively, 4675 and 3995µg/g dry wt., far more than the minimum of 1000µg/g dry wt. for a Cu hyperaccumulator. The plant root at all the doses tolerated Cu, with the tolerance index ranging from 94-62.7. The soil to plant metal uptake capacity, indicated by extraction coefficient and the root to shoot translocation, indicated by translocation factor, at all the doses of Cu were >1, pointed towards efficient phytoremediation potential. PMID:26773830

  19. 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 (δ60Ni = 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 (Δ60Nisoil-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 (Δ60Niwhole plant-soil up to 0.40‰). Fractions of Ni extracted by DTPA (diethylenetriaminepentaacetic acid) presented isotopically heavy compositions compared to the soil (Δ60NiDTPA-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 (Δ60Nileaves-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.

  20. Transcriptome analyses of Populus x euramericana clone I-214 leaves exposed to excess zinc.

    PubMed

    Di Baccio, Daniela; Galla, Giulio; Bracci, Tania; Andreucci, Andrea; Barcaccia, Gianni; Tognetti, Roberto; Sebastiani, Luca

    2011-12-01

    Zinc (Zn) is an essential element for plant growth and development, but at high levels this metal can become toxic. Hyperaccumulator species are often not suitable for phytoremediation technologies because they need to be fast growing and have high biomass production, such as those of the Populus genus. Comparative genomics studies of poplars subjected to stress conditions such as heavy metal contamination have generated resources useful for improving the annotation of genes and have provided novel insights in the defense/tolerance mechanisms governing adaptation in non-hyperaccumulator plants. Using a microarray-based comparative analysis, we identified functional gene sets that are differentially regulated in the leaves of Populus × euramericana clone I-214 subjected to an excess but sub-lethal dose of Zn (1 mM). Eco-physiological and chemical analyses confirmed the results obtained in previous similar experiments. A total of 3861 expressed sequence tags (ESTs) were differentially expressed and grouped into two distinct libraries of up-regulated (40%) and down-regulated (60%) putative genes. The annotation of genes and gene products according to the Gene Ontology vocabularies was performed using Blast2GO software. The two transcriptome data sets were used to query all known Kyoto Encyclopedia of Genes and Genomes (KEGG) biosynthetic pathways of the genes identified in this study. The most represented molecular functions and biological processes were nucleotide binding and transcription, transport and response to stress and abiotic and biotic stimuli. The chloroplast, mitochondrion and their membrane systems were the cellular components most affected by excess Zn, as well as the photosynthetic, defense, sulfur and glutathione (GSH) metabolic pathways. The most up-regulated genes encoded electron carriers associated with ferrodoxin, the small subunit of ribulose-bisphosphate carboxylase oxygenase, and enzymes involved in GSH metabolism. This study is the most in-depth transcriptome and gene-annotation analysis of a hybrid poplar to date. The results are presented and critically discussed in terms of poplar response/tolerance to Zn stress for the characterization of non-hyperaccumulator phenotypes and the identification of candidate genes in perennial plants. These genetic findings provide useful information on tree species' adaptation to metal stress and provide powerful tools for the selection and/or genetic manipulation of stress-tolerant poplar clones. PMID:22038866

  1. 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

  2. Increase of free cysteine and citric acid in plant cells exposed to cobalt ions.

    PubMed

    Oven, Matjaz; Grill, Erwin; Golan-Goldhirsh, Avi; Kutchan, Toni M; Zenk, Meinhart H

    2002-07-01

    Cobalt complexation was investigated in a suspension cell culture of the cobalt hyperaccumulator Crotalaria cobalticola. C. cobalticola cells were more tolerant towards cobalt ions than the suspension cells of the non-accumulators Rauvolfia serpentina and Silene cucubalus. While the concentration of various compounds increased in cells of C. cobalticola challenged with cobalt ions, phytochelatin biosynthesis was not induced. Instead, the exposure to cobalt ions resulted in the increase of citrate and cysteine in cells. Size exclusion chromatography demonstrated the co-elution of cobalt and cysteine in C. cobalticola cell extracts. A significant increase in cysteine was observed also in cells of R. serpentina and S. cucubalus when they were exposed to cobalt ions. These results suggest that free cysteine is involved in cobalt ion complexation in plant cells. PMID:12052512

  3. 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

  4. Contaminated soils salinity, a threat for phytoextraction?

    PubMed

    Sirguey, Catherine; Ouvrard, Stphanie

    2013-04-01

    Phytoremediation, given the right choice of plant, may be theoretically applicable to multi-contamination. Laboratory and some field trials have proven successful, but this ideal technique is in all cases dependent on plant growth ability on (generally) low-fertility soil or media. While contaminant concentration has often been proposed as an explanation for plant growth limitation, other factors, commonly occurring in industrial soils, such as salinity, should be considered. The present work highlights the fact that besides contaminants (trace elements and PAH), soil salinity may strongly affect germination and growth of the hyperaccumulator Noccaea caerulescens. Elevated concentrations of nitrate proved highly toxic for seed germination. At the growth stage the salt effect (sulfate) seemed less significant and the limited biomass production observed could be attributed mostly to organic contamination. PMID:23245576

  5. Seasonal effects on accumulation of microbial indicator organisms by Mercenaria mercenaria.

    PubMed

    Burkhardt, W; Watkins, W D; Rippey, S R

    1992-03-01

    The ability of hard-shelled clams (Mercenaria mercenaria) to accumulate fecal coliforms and other microorganisms (Escherichia coli, Clostridium perfringens, and male-specific bacteriophages) was determined over a 1-year period. Twenty separate trails were conducted during different seasons to encompass a wide range of water temperatures. The greatest accumulation of microorganisms in hard-shelled clams occurred during certain periods in the spring, at temperatures ranging from 11.5 to 21.5 degrees C. These periods of hyperaccumulation did not always coincide for all organisms; the accumulation of bacteriophages was not predicted by the accumulation of either fecal coliforms or C. perfringens. Bacteriophages and C. perfringens showed significantly higher rates of accumulation than either the fecal coliform group or E. coli, especially during the spring. The higher incidence of human viral gastroenteritis associated with the consumption of shellfish during this period may be a result of the extraordinary concentration of certain microorganisms, including enteric viral pathogens. PMID:1575484

  6. Transgenic plants in phytoremediation: recent advances and new possibilities.

    PubMed

    Cherian, Sam; Oliveira, M Margarida

    2005-12-15

    Phytoremediation, the use of plants and their associated microbes to remedy contaminated soils, sediments, and groundwater, is emerging as a cost-effective and environmentally friendly technology. Due in large part to its aesthetic appeal, this technology has gained increasing attention over the past 10 years. Phytoremediation uses different plant processes and mechanisms normally involved in the accumulation, complexation, volatilization, and degradation of organic and inorganic pollutants. Certain plants, called hyperaccumulators, are good candidates in phytoremediation, particularly for the removal of heavy metals. Phytoremediation efficiency of plants can be substantially improved using genetic engineering technologies. Recent research results, including overexpression of genes whose protein products are involved in metal uptake, transport, and sequestration, or act as enzymes involved in the degradation of hazardous organics, have opened up new possibilities in phytoremediation. This paper provides a critical review of the recent progress made toward the development of transgenic plants with improved phytoremediation capabilities and their potential use in environmental cleanup. PMID:16475312

  7. The tolerance efficiency of Panicum maximum and Helianthus annuus in TNT-contaminated soil and nZVI-contaminated soil.

    PubMed

    Jiamjitrpanich, Waraporn; Parkpian, Preeda; Polprasert, Chongrak; Laurent, Franois; Kosanlavit, Rachain

    2012-01-01

    This study was designed to compare the initial method for phytoremediation involving germination and transplantation. The study was also to determine the tolerance efficiency of Panicum maximum (Purple guinea grass) and Helianthus annuus (Sunflower) in TNT-contaminated soil and nZVI-contaminated soil. It was found that the transplantation of Panicum maximum and Helianthus annuus was more suitable than germination as the initiate method of nano-phytoremediation potting test. The study also showed that Panicum maximum was more tolerance than Helianthus annuus in TNT and nZVI-contaminated soil. Therefore, Panicum maximum in the transplantation method should be selected as a hyperaccumulated plant for nano-phytoremediation potting tests. Maximum tolerance dosage of Panicum maximum to TNT-concentration soil was 320 mg/kg and nZVI-contaminated soil was 1000 mg/kg in the transplantation method. PMID:22702809

  8. Effect of lead on root growth.

    PubMed

    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

  9. Assessment of bioaccumulation of heavy metal by Pteris vittata L. growing in the vicinity of fly ash.

    PubMed

    Kumari, Alka; Lal, Brij; Pakade, Yogesh B; Chand, Piar

    2011-09-01

    Pteris vittata L. subsp. vittata, a potential arsenic hyperaccumulator fern, growing naturally in the vicinity offly ash was analyzed for the concentration of nine heavy metals (Fe, Cu, Zn Ni, Al, Cr, Pb, Si, and As) from five different sites around of Kanti Thermal Power Station at Muzaffarpur in Bihar State, India. Metal accumulation in P. vittata was correlated with the level of pollution at five selected sampling sites. The results revealed significantly more accumulation of these metals in the above ground parts of the plant than the parts below ground. Statistical parameters such as the coefficient of variation (CV%) showed a higher for As, Cu, Cr, and a lower one for Fe, Ni, Al. There was high spatial variability in the total metal concentration at different sites. The present study confirmed that P. vittata is a heavy metals accumulator and that it is a highly suitable candidate for phytoremediation of metal contaminated wastelands. PMID:21972518

  10. Phytoremediation potential of paragrass--an in situ approach for chromium contaminated soil.

    PubMed

    Mohanty, Monalisa; Patra, Hemanta Kumar

    2012-09-01

    The present in situ phytoextraction approach uses paragrass (Brachiaria mutica (Forssk) Stapf) as a hyper accumulator for attenuation of chromium level in soil and mine waste water at South Kaliapani chromite mine area of Orissa. The bioconcentration factor (BCF) for Cr was maximum (0.334) in 100 days grown paragrass weeds. Transportation index (Ti) i.e. 6.16 and total accumulation rate (TAR) i.e. 8.2 mg kg(-1)day(-1) was maximum in 125 days old paragrass grown in Cr contaminated experimental cultivated plots. Cr bioaccumulation in roots was nearly 1000 times more than shoots. Paragrass showed luxuriant growth with massive fibrous roots when grown over Cr contaminated soils (11,170 mg/ kg dry soil). Cr bioaccumulation varies significantly with plant age, biomass and level of Cr contamination in irrigated mine waste water and soil. Paragrass could be used as hyperaccumulators as it showed rapid massive growth with a high tolerance to Cr. PMID:22908645

  11. Phytoremediation potential of paragrass--an in situ approach for chromium contaminated soil.

    TOXLINE Toxicology Bibliographic Information

    Mohanty M; Patra HK

    2012-09-01

    The present in situ phytoextraction approach uses paragrass (Brachiaria mutica (Forssk) Stapf) as a hyper accumulator for attenuation of chromium level in soil and mine waste water at South Kaliapani chromite mine area of Orissa. The bioconcentration factor (BCF) for Cr was maximum (0.334) in 100 days grown paragrass weeds. Transportation index (Ti) i.e. 6.16 and total accumulation rate (TAR) i.e. 8.2 mg kg(-1)day(-1) was maximum in 125 days old paragrass grown in Cr contaminated experimental cultivated plots. Cr bioaccumulation in roots was nearly 1000 times more than shoots. Paragrass showed luxuriant growth with massive fibrous roots when grown over Cr contaminated soils (11,170 mg/ kg dry soil). Cr bioaccumulation varies significantly with plant age, biomass and level of Cr contamination in irrigated mine waste water and soil. Paragrass could be used as hyperaccumulators as it showed rapid massive growth with a high tolerance to Cr.

  12. Biological and ecophysiological reactions of white wall rocket (Diplotaxis erucoides L.) grown on sewage sludge compost.

    PubMed

    Korboulewsky, Nathalie; Bonin, Gilles; Massiani, Catherine

    2002-01-01

    We studied the effects of sewage sludge compost on white wall rocket (Diplotaxis erucoides L.) compared with mineral fertilization and control (without any fertilizer) in a greenhouse experiment. The plants grown on the compost-amended soil showed a different growth dynamic: a significant delay in flowering and a bigger root system. Both the compost and the fertilization treatments increased biomass and seed yield. Heavy metal (Cu, Cd, Zn, Ni) distribution within the plant was in the following order: roots > leaves > stems, except for zinc which was homogeneously distributed. The balance of mineral nutrition was not affected by treatments. Zinc was the trace element which was most taken up. Unlike many species of Brassicaceae, white wall rocket is not a hyperaccumulator. Although sewage sludge compost improved plant growth, delay in flowering shows that it is necessary to take precautions when spreading sewage sludge in natural areas. PMID:11916052

  13. [Plant sulfate assimilation and regulation of the activity of related enzymes under cadmium stress].

    PubMed

    Sun, Xue-Mei; Yang, Zhi-Min

    2006-02-01

    The complexation and sequestration of heavy metal ions (e.g. Cd) by the cysteine-rich polypeptides known as phytochelatins (PC) are thought to confer heavy metal hyperaccumulation and tolerance in some plant species. PC is synthesized enzymatically from glutathione. The tripeptide glutathione is a product of primary sulfur metabolism. A variety of enzymes or proteins are involved in sulfur assimilation including sulfate transporters (STs), ATP sulfurylase (ATPS), APS reductase (APSR), sulfite reductase (SiR), glutathione synthetase (GS) and phytochelatin synthesis (PCS). These enzymes or proteins are upstream-regulated by Cd at either the metabolic or the genetic level under metal stress. Increasing evidence shows that enhancement of sulfate uptake and reduction occurs with the production of PC in plants under heavy metal stress. In this article, the key aspects of our recent understanding of regulatory mechanisms involved in the relation between the sulfate assimilation and phytochelatin synthesis are described. PMID:16477125

  14. 2D DIGE proteomic analysis highlights delayed postnatal repression of ?-fetoprotein expression in homocystinuria model mice.

    PubMed

    Kamata, Shotaro; Akahoshi, Noriyuki; Ishii, Isao

    2015-01-01

    Cystathionine ?-synthase-deficient (Cbs (-/-)) mice, an animal model for homocystinuria, exhibit hepatic steatosis and juvenile semilethality via as yet unknown mechanisms. The plasma protein profile of Cbs (-/-) mice was investigated by proteomic analysis using two-dimensional difference gel electrophoresis and matrix-assisted laser desorption/ionization-time of flight/mass spectrometry. We found hyperaccumulation of ?-fetoprotein (AFP) and downregulation of most other plasma proteins. AFP was highly expressed in fetal liver, but its expression declined dramatically via transcriptional repression after birth in both wild-type and Cbs (-/-) mice. However, the repression was delayed in Cbs (-/-) mice, causing high postnatal AFP levels, which may relate to transcriptional repression of most plasma proteins originating from liver and the observed hepatic dysfunction. PMID:26199862

  15. 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

  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. 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 doseresponse 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

  18. Arsenic uptake by Lemna minor in hydroponic system.

    PubMed

    Goswami, Chandrima; Majumder, Arunabha; Misra, Amal Kanti; Bandyopadhyay, Kaushik

    2014-01-01

    Arsenic is hazardous and causes several ill effects on human beings. Phytoremediation is the use of aquatic plants for the removal of toxic pollutants from external media. In the present research work, the removal efficiency as well as the arsenic uptake capacity of duckweed Lemna minor has been studied. Arsenic concentration in water samples and plant biomass were determined by AAS. The relative growth factor of Lemna minor was determined. The duckweed had potential to remove as well as uptake arsenic from the aqueous medium. Maximum removal of more than 70% arsenic was achieved atinitial concentration of 0.5 mg/1 arsenic on 15th day of experimental period of 22 days. Removal percentage was found to decrease with the increase in initial concentration. From BCF value, Lemna minor was found to be a hyperaccumulator of arsenic at initial concentration of 0.5 mg/L, such that accumulation decreased with increase in initial arsenic concentration. PMID:24933913

  19. 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

  20. 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, Ccile; Pauwels, Maxime; Gonneau, Cdric

    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

  1. The ABC transporter ABCG1 is required for suberin formation in potato tuber periderm.

    PubMed

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

    2014-08-01

    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

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

    PubMed

    Mihailovic, N; Andreji?, G; Deletovi?,

    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

  3. 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

  4. 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

  5. Seasonal effects on accumulation of microbial indicator organisms by Mercenaria mercenaria.

    PubMed Central

    Burkhardt, W; Watkins, W D; Rippey, S R

    1992-01-01

    The ability of hard-shelled clams (Mercenaria mercenaria) to accumulate fecal coliforms and other microorganisms (Escherichia coli, Clostridium perfringens, and male-specific bacteriophages) was determined over a 1-year period. Twenty separate trails were conducted during different seasons to encompass a wide range of water temperatures. The greatest accumulation of microorganisms in hard-shelled clams occurred during certain periods in the spring, at temperatures ranging from 11.5 to 21.5 degrees C. These periods of hyperaccumulation did not always coincide for all organisms; the accumulation of bacteriophages was not predicted by the accumulation of either fecal coliforms or C. perfringens. Bacteriophages and C. perfringens showed significantly higher rates of accumulation than either the fecal coliform group or E. coli, especially during the spring. The higher incidence of human viral gastroenteritis associated with the consumption of shellfish during this period may be a result of the extraordinary concentration of certain microorganisms, including enteric viral pathogens. PMID:1575484

  6. 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

  7. Tolerance of Ornamental Succulent Plant Crown of Thorns (Euphorbia milli) to Chromium and its Remediation.

    PubMed

    Ramana, Sivakoti; Biswas, Ashis Kumar; Singh, Amar Bahadur; Ajay; Ahirwar, Narendar Kumar; Subba Rao, Annangi

    2015-01-01

    The potential of an ornamental shrub Crown of thorns (Euphorbia milli) was evaluated for remediation of soil contaminated with Cr. The plant is one of the rare succulent ornamental shrubs with a slow to moderate growth rate and is capable of blooming almost year-round. The plant could tolerate well up to 75 mg of applied Cr and beyond that there was mortality of plants. Though the plant could not be classified as a hyperaccumulator, the plant was still very efficient in translocating Cr from roots to shoots as evident from the data on uptake and translocation efficiency values. The translocation efficiency of over 80% in our study demonstrates that a large proportion of Cr has been translocated to the harvestable biomass of the plant and therefore, this plant could be effectively recommended for the remediation of soils contaminated with low to medium level of contamination i.e., up to 50 mg/kg soil. PMID:25409249

  8. Heavy metals concentration in plants growing on mine tailings in Central Mexico.

    PubMed

    Franco-Hernndez, M O; Vsquez-Murrieta, M S; Patio-Siciliano, A; Dendooven, L

    2010-06-01

    Metal concentrations were measured in plants growing on heavily contaminated tailings from a mine active since about 1800 in San Luis Potos (Mexico). Viguiera dentata (Cav.) Spreng., Parthenium bipinnatifidum (Ort.) Rollins, Flaveria angustifolia (Cav.) Pers., F. trinervia (Spreng.) C. Mohr. and Sporobolusindicus (L.) R. Br. were tolerant to high As, Cu, Pb and Zn concentrations. Of those, S.indicus excluded heavy metals from its shoots, while P. bipinnatifidum and F. angustifolia accumulated them. V. dentata and P. bipinnatifidum were accumulators of As, but not hyperaccumulators. It was found that V. dentata,P. bipinnatifidum, F. angustifolia, F. trinervia and S.indicus, could be used to vegetate soils contaminated with As, Cu, Pb and Zn. Ambrosiaartemisifolia could be used to remediate soils contaminated with Zn, S. amplexicaulis those with Cu and F. angustifolia and F. trinervia those with As, as they have a strong capacity to accumulate those metals. PMID:20116240

  9. 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.

  10. Phytoremediation potential of aquatic macrophyte, Azolla.

    PubMed

    Sood, Anjuli; Uniyal, Perm L; Prasanna, Radha; Ahluwalia, Amrik S

    2012-03-01

    Aquatic macrophytes play an important role in the structural and functional aspects of aquatic ecosystems by altering water movement regimes, providing shelter to fish and aquatic invertebrates, serving as a food source, and altering water quality by regulating oxygen balance, nutrient cycles, and accumulating heavy metals. The ability to hyperaccumulate heavy metals makes them interesting research candidates, especially for the treatment of industrial effluents and sewage waste water. The use of aquatic macrophytes, such as Azolla with hyper accumulating ability is known to be an environmentally friendly option to restore polluted aquatic resources. The present review highlights the phytoaccumulation potential of macrophytes with emphasis on utilization of Azolla as a promising candidate for phytoremediation. The impact of uptake of heavy metals on morphology and metabolic processes of Azolla has also been discussed for a better understanding and utilization of this symbiotic association in the field of phytoremediation. PMID:22396093

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

    PubMed

    Liu, Zhouli; Chen, Wei; He, Xingyuan; 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

  12. 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

  13. 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.

  14. Flame atomic absorption spectrometric determination of Pb, Cd, and Cu in Pinus nigra L. and Eriobotrya japonica leaves used as biomonitors in environmental pollution.

    PubMed

    Kaya, Gokce; Ozcan, Cemile; Yaman, Mehmet

    2010-02-01

    The assessment of trace metal pollution in Gaziantep city-Turkey has been studied using plant leaves of Pinus nigra L. and Eriobotrya japonica as biomonitor. The concentrations up to 3,056 mg Pb kg(-1) in the needles of Pinus nigra L., and 367 ng Cd g(-1) in the leaves of Eriobotrya japonica were determined. The observed Cu concentrations were in range of 1.6-7.1 mg kg(-1). The Pb, Cd, and Cu levels in soils were determined to be in the range of 17-602, 0.142-0.656, and 12-38 mg kg(-1), respectively. It was concluded that Pinus nigra L. can be considered as both biomonitor of atmospheric Pb pollution and hyperaccumulator plant. PMID:19784536

  15. 2D DIGE proteomic analysis highlights delayed postnatal repression of ?-fetoprotein expression in homocystinuria model mice

    PubMed Central

    Kamata, Shotaro; Akahoshi, Noriyuki; Ishii, Isao

    2015-01-01

    Cystathionine ?-synthase-deficient (Cbs?/?) mice, an animal model for homocystinuria, exhibit hepatic steatosis and juvenile semilethality via as yet unknown mechanisms. The plasma protein profile of Cbs?/? mice was investigated by proteomic analysis using two-dimensional difference gel electrophoresis and matrix-assisted laser desorption/ionization-time of flight/mass spectrometry. We found hyperaccumulation of ?-fetoprotein (AFP) and downregulation of most other plasma proteins. AFP was highly expressed in fetal liver, but its expression declined dramatically via transcriptional repression after birth in both wild-type and Cbs?/? mice. However, the repression was delayed in Cbs?/? mice, causing high postnatal AFP levels, which may relate to transcriptional repression of most plasma proteins originating from liver and the observed hepatic dysfunction. PMID:26199862

  16. Metal and metalloid containing natural products and a brief overview of their applications in biology, biotechnology and biomedicine.

    PubMed

    Dias, Daniel A; Kouremenos, Konstantinos A; Beale, David J; Callahan, Damien L; Jones, Oliver A H

    2016-02-01

    Bioinorganic natural product chemistry is a relatively unexplored but rapidly developing field with enormous potential for applications in biology, biotechnology (especially in regards to nanomaterial development, synthesis and environmental cleanup) and biomedicine. In this review the occurrence of metals and metalloids in natural products and their synthetic derivatives are reviewed. A broad overview of the area is provided followed by a discussion on the more common metals and metalloids found in natural sources, and an overview of the requirements for future research. Special attention is given to metal hyperaccumulating plants and their use in chemical synthesis and bioremediation, as well as the potential uses of metals and metalloids as therapeutic agents. The potential future applications and development in the field are also discussed. PMID:26553050

  17. 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

  18. 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

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

    DOEpatents

    Meagher, Richard B.; Balish, Rebecca S.; Tehryung, Kim; McKinney, Elizabeth C.

    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.

  20. Arbuscular mycorrhiza and heavy metal tolerance.

    PubMed

    Hildebrandt, Ulrich; Regvar, Marjana; Bothe, Hermann

    2007-01-01

    Arbuscular mycorrhizal fungi (AMF) have repeatedly been demonstrated to alleviate heavy metal stress of plants. The current manuscript summarizes results obtained to date on the colonization of plants by AMF in heavy metal soils, the depositions of heavy metals in plant and fungal structures and the potential to use AMF-plant combinations in phytoremediation, with emphasis on pennycresses (Thlaspi ssp.). The focus of this manuscript is to describe and discuss studies on the expression of genes in plants and fungi under heavy metal stress. The summary is followed by data on differential gene expression in extraradical mycelia (ERM) of in vitro cultured Glomus intraradices Sy167 supplemented with different heavy metals (Cd, Cu or Zn). The expression of several genes encoding proteins potentially involved in heavy metal tolerance varied in their response to different heavy metals. Such proteins included a Zn transporter, a metallothionein, a 90 kD heat shock protein and a glutathione S-transferase (all assignments of protein function are putative). Studies on the expression of the selected genes were also performed with roots of Medicago truncatula grown in either a natural, Zn-rich heavy metal "Breinigerberg" soil or in a non-polluted soil supplemented with 100 microM ZnSO(4). The transcript levels of the genes analyzed were enhanced up to eight fold in roots grown in the heavy metal-containing soils. The data obtained demonstrate the heavy metal-dependent expression of different AMF genes in the intra- and extraradical mycelium. The distinct induction of genes coding for proteins possibly involved in the alleviation of damage caused by reactive oxygen species (a 90 kD heat shock protein and a glutathione S-transferase) might indicate that heavy metal-derived oxidative stress is the primary concern of the fungal partner in the symbiosis. PMID:17078985

  1. 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

  2. Annual plants under cyclic disturbance regime: better understanding through model aggregation.

    PubMed

    Pagel, Jrn; Fritzsch, Katrin; Biedermann, Robert; Schrder, Boris

    2008-12-01

    In their application for conservation ecology, "classical" analytical models and individual-based simulation models (IBMs) both entail their specific strengths and weaknesses, either in providing a detailed and realistic representation of processes or in regard to a comprehensive model analysis. This well-known dilemma may be resolved by the combination of both approaches when tackling certain problems of conservation ecology. Following this idea, we present the complementary use of both an IBM and a matrix population model in a case study on grassland conservation management. First, we develop a spatially explicit IBM to simulate the long-term response of the annual plant Thlaspi perfoliatum (Brassicaceae), claspleaf pennycress, to different management schemes (annual mowing vs. infrequent rototilling) based on field experiments. In order to complement the simulation results by further analyses, we aggregate the IBM to a spatially nonexplicit deterministic matrix population model. Within the periodic environment created by management regimes, population dynamics are described by periodic products of annual transition matrices. Such periodic matrix products provide a very conclusive framework to study the responses of species to different management return intervals. Thus, using tools of matrix model analysis (e.g., loop analysis), we can both identify dormancy within the age-structured seed bank as the pivotal strategy for persistence under cyclic disturbance regimes and reveal crucial thresholds in some less certain parameters. Results of matrix model analyses are therefore successfully tested by comparing their results to the respective IBM simulations. Their implications for an enhanced scientific basis for management decisions are discussed as well as some general benefits and limitations of the use of aggregating modeling approaches in conservation. PMID:19263893

  3. [Promotion effects of microorganisms on phytoremediation of heavy metals-contaminated soil].

    PubMed

    Yang, Zhuo; Wang, Zhan-Li; Li, Bo-Wen; Zhang, Rui-Fang

    2009-08-01

    Taking Brassica juncea as a hyperaccumulator, a pot experiment was conducted to study the effects of Bacillusme gaterium - Bacillus mucilaginosus mixed agent and Aspergillus niger 30177 fermentation liquor on the phytoremediation of Cd, Pb, and Zn-contaminated soil. The B. gaterium - B. mucilaginosus mixed agent not only promoted the growth of B. juncea, but also increased the soil Cd, Pb, and Zn uptake by the hyperaccumulator, with the phytoremediation efficiency enhanced greatly. The enrichment amount of Cd, Pb and Zn in B. juncea on the soil added with soluble Cd, Pb and Zn increased by 1.18, 1.54 and 0.85 folds, while that on the soil added with Cd, Pb and Zn-contaminated sediment increased by 4.00, 0. 64 and 0. 65 folds, respectively, compared with the control. A. niger 30177 fermentation liquor increased the soil Cd, Pb, and Zn uptake by B. juncea. Comparing with the control, the enrichment amount of Cd, Pb and Zn in aboveground part of B. juncea on the soil added with soluble Cd, Pb and Zn increased by 88.82%, 129.04% and 16.80%, while that on the soil added with Cd, Pb and Zn-contaminated sediment increased by 78.95%, 113.63% and 33.85%, respectively. However, A. niger 30177 fermentation liquor decreased the B. juncea biomass greatly, having less effect in the enhancement of phytoremediation efficiency. The analysis of reversed-phase high performance liquid chromatography showed that the fermentation liquor of B. gaterium and B. mucilaginosus contained some organic acids such as oxalic acid and citric acid. These acids could dissolve the heavy metals to some degree, and accordingly, enhance the bioavailability of the metals. PMID:19947228

  4. 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

  5. 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

  6. Bacterially induced weathering of ultramafic rock and its implications for phytoextraction.

    PubMed

    Becerra-Castro, Cristina; Kidd, Petra; Kuffner, Melanie; Prieto-Fernndez, ngeles; Hann, Stephan; Monterroso, Carmela; Sessitsch, Angela; Wenzel, Walter; Puschenreiter, Markus

    2013-09-01

    The bioavailability of metals in soil is often cited as a limiting factor of phytoextraction (or phytomining). Bacterial metabolites, such as organic acids, siderophores, or biosurfactants, have been shown to mobilize metals, and their use to improve metal extraction has been proposed. In this study, the weathering capacities of, and Ni mobilization by, bacterial strains were evaluated. Minimal medium containing ground ultramafic rock was inoculated with either of two Arthrobacter strains: LA44 (indole acetic acid [IAA] producer) or SBA82 (siderophore producer, PO4 solubilizer, and IAA producer). Trace elements and organic compounds were determined in aliquots taken at different time intervals after inoculation. Trace metal fractionation was carried out on the remaining rock at the end of the experiment. The results suggest that the strains act upon different mineral phases. LA44 is a more efficient Ni mobilizer, apparently solubilizing Ni associated with Mn oxides, and this appeared to be related to oxalate production. SBA82 also leads to release of Ni and Mn, albeit to a much lower extent. In this case, the concurrent mobilization of Fe and Si indicates preferential weathering of Fe oxides and serpentine minerals, possibly related to the siderophore production capacity of the strain. The same bacterial strains were tested in a soil-plant system: the Ni hyperaccumulator Alyssum serpyllifolium subsp. malacitanum was grown in ultramafic soil in a rhizobox system and inoculated with each bacterial strain. At harvest, biomass production and shoot Ni concentrations were higher in plants from inoculated pots than from noninoculated pots. Ni yield was significantly enhanced in plants inoculated with LA44. These results suggest that Ni-mobilizing inoculants could be useful for improving Ni uptake by hyperaccumulator plants. PMID:23793627

  7. 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

  8. 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 4mM, 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 30mg Cdkg(-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

  9. Copper uptake by Elsholtzia splendens and Silene vulgaris and assessment of copper phytoavailability in contaminated soils.

    PubMed

    Song, Jing; Zhao, Fang-Jie; Luo, Yong-Ming; McGrath, Steve P; Zhang, Hao

    2004-01-01

    Tolerance and metal uptake are two essential characteristics required for phytoextraction of metals from contaminated soils. We compared tolerance and Cu uptake of Elsholtzia splendens (reported previously to be a Cu hyperaccumulator) with Silene vulgaris (the Imsbach population, a well-known Cu-tolerant excluder species), using 30 soils varying widely in total Cu concentration (19-8645 mg kg(-1)). We further investigated the effectiveness of different soil testing methods for predicting plant metal uptake. The results showed that both Elsholtzia splendens and Silene vulgaris were tolerant to Cu, especially Silene vulgaris. However, Elsholtzia splendens did not hyperaccumulate Cu, but behaved as a typical Cu excluder like Silene vulgaris. The concentrations of Cu in both plants correlated more closely with 1 M NH4NO3 extractable Cu, soil solution Cu, or effective Cu concentration determined using DGT, than with soil total Cu, EDTA extractable Cu or free Cu2+ activity. The relationships between soil solution properties and root Cu concentrations were further investigated using multiple regression. The results showed that increasing soil solution pH increased root Cu concentration when free Cu2+ activity was held constant, suggesting a higher phytoavailability of free Cu2+ at a higher pH. Soil solution DOC appeared to play two contrasting roles on the phytoavailability of Cu: (1) reducing Cu availability by complexing Cu; and (2) increasing Cu availability at the same level of free Cu2+ activity by providing a strong buffer for free Cu2+. The results are consistent with the intensity/capacity concept for phytoavailability of metals in soils. PMID:14720473

  10. Dissolution of different zinc salts and zn uptake by Sedum alfredii and maize in mono- and co-cropping under hydroponic culture.

    PubMed

    Jiang, Cheng'ai; Wu, Qitang; Zeng, Shucai; Chen, Xian; Wei, Zebin; Long, Xinxian

    2013-09-01

    Previous soil pot and field experiments demonstrated that co-cropping the hyperaccumulator Sedum alfredii with maize increased Zn phytoextraction by S. alfredii and decreased Zn uptake by maize shoots. This hydroponic experiment was conducted to investigate whether the facilitation of Zn phytoextraction by S. alfredii resulted from improved dissolution in this co-cropping system and its relation to root exudates. S. alfredii and maize were mono- and co-cropped (without a root barrier) in nutrient solution spiked with four Zn compounds, ZnS, ZnO, Zn3(PO4)2 and 5ZnO x 2CO3-4H2O (represented as ZnCO3) at 1000 mg/L Zn for 15 days without renewal of nutrient solution after pre-culture. The root exudates were collected under incomplete sterilization and analyzed. The results indicated that the difference in Zn salts had a greater influence on the Zn concentration in maize than for S. alfredii, varying from 210-2603 mg/kg for maize shoots and 6445-12476 mg/kg for S. alfredii in the same order: ZnCO3 > ZnO > Zn3(PO4)2 > ZnS. For the four kinds of Zn sources in this experiment, co-cropping with maize did not improve Zn phytoextraction by S. alfredii. In most cases, compared to co-cropped and mono-cropped maize, mono-cropped S. alfredii resulted in the highest Zn2+ concentration in the remaining nutrient solution, and also had a higher total concentration of low molecular weight organic acids (LMWOA) and lower pH of root exudation. Root exudates did partly influence Zn hyperaccumulation in S. alfredii. PMID:24520733

  11. Enhancement of cadmium tolerance and accumulation by introducing Perilla frutescens (L.) Britt var. frutescens genes in Nicotiana tabacum L. plants.

    PubMed

    Wei, Keqiang; Pang, Shengxi; Yang, Junxian; Wei, Zhizhong

    2015-04-01

    The tobacco has the genetic potential to remove toxic metals from the soil. To develop hyperaccumulating tobacco plants, distant hybridization between tobacco (Nicotiana tabacum L.), a high-biomass crop, and Perilla frutescens (L.) Britt var. frutescens, a newfound Cd-hyperaccumulator species, was carried out using a novel method viz. pollination following grafting. Their hybrid nature was preliminarily confirmed by phenotype, isozyme pattern, random amplified polymorphic DNA (RAPD) and metabolites analysis. About 120 putative F2 hybrids derived from the cross-combination [(N. sylvestris Speg. & Comes rootstock?+?N. tabacum L. var. 78-04 scion) P. frutescens (L.) Britt var. frutescens] were then subjected to up to 300 ?M CdCl2 in hydroponic conditions for 10 days. Results showed five seedlings were more resistant to Cd than female parent and accumulated 314.6??99.9 mg kg(-1) Cd in their aerial biomass, which was 5.7 times greater than that in "78-04" tobacco (47.2??3.56 mg kg(-1)) (P???0.05). Two of these seedlings exceeded male parent P. frutescens in the Cd concentration of shoots and reached 424 and 396 mg kg(-1), which was 13% and 6% greater for that of perilla (374.2??10.38 mg kg(-1)), respectively. Compared with parents, two other F2 hybrids tended to accumulate more Cd in the root with bioconcentration factor (BCF) 7.05 and 5.17, respectively. Only one hybrid showed lower Cd concentration but transferred Cd more effectively from the root to the shoot than parents and other F2 hybrids, with the maximum translocation factor (TF) value 1.37. These indicated that the introduction of P. frutescens genes could obviously enhance the cadmium tolerance and accumulation of superior individuals. PMID:25567061

  12. Bioaugmentation with Endophytic Bacterium E6S Homologous to Achromobacter piechaudii Enhances Metal Rhizoaccumulation in Host Sedum plumbizincicola.

    PubMed

    Ma, Ying; Zhang, Chang; Oliveira, Rui S; Freitas, Helena; Luo, Yongming

    2016-01-01

    Application of hyperaccumulator-endophyte symbiotic systems is a potential approach to improve phytoremediation efficiency, since some beneficial endophytic bacteria are able to detoxify heavy metals, alter metal solubility in soil, and facilitate plant growth. The objective of this study was to isolate multi-metal resistant and plant beneficial endophytic bacteria and to evaluate their role in enhancing plant growth and metal accumulation/translocation. The metal resistant endophytic bacterial strain E6S was isolated from stems of the Zn/Cd hyperaccumulator plant Sedum plumbizincicola growing in metalliferous mine soils using Dworkin and Foster salts minimal agar medium with 1-aminocyclopropane-1-carboxylate (ACC) as the sole nitrogen source, and identified as homologous to Achromobacter piechaudii based on morphological and biochemical characteristics, partial 16S rDNA sequence and phylogenetic analysis. Strain E6S showed high level of resistance to various metals (Cd, Zn, and Pb). Besides utilizing ACC, strain E6S exhibited plant beneficial traits, such as solubilization of phosphate and production of indole-3-acetic acid. Inoculation with E6S significantly increased the bioavailability of Cd, Zn, and Pb in soil. In addition, bacterial cells bound considerable amounts of metal ions in the following order: Zn > Cd >Pb. Inoculation of E6S significantly stimulated plant biomass, uptake and bioaccumulation of Cd, Zn, and Pb. However, E6S greatly reduced the root to shoot translocation of Cd and Zn, indicating that bacterial inoculation assisted the host plant to uptake and store heavy metals in its root system. Inoculation with the endophytic bacterium E6S homologous to A. piechaudii can improve phytostabilization of metalliferous soils due to its effective ability to enhance in situ metal rhizoaccumulation in plants. PMID:26870079

  13. Bioaugmentation with Endophytic Bacterium E6S Homologous to Achromobacter piechaudii Enhances Metal Rhizoaccumulation in Host Sedum plumbizincicola

    PubMed Central

    Ma, Ying; Zhang, Chang; Oliveira, Rui S.; Freitas, Helena; Luo, Yongming

    2016-01-01

    Application of hyperaccumulator-endophyte symbiotic systems is a potential approach to improve phytoremediation efficiency, since some beneficial endophytic bacteria are able to detoxify heavy metals, alter metal solubility in soil, and facilitate plant growth. The objective of this study was to isolate multi-metal resistant and plant beneficial endophytic bacteria and to evaluate their role in enhancing plant growth and metal accumulation/translocation. The metal resistant endophytic bacterial strain E6S was isolated from stems of the Zn/Cd hyperaccumulator plant Sedum plumbizincicola growing in metalliferous mine soils using Dworkin and Foster salts minimal agar medium with 1-aminocyclopropane-1-carboxylate (ACC) as the sole nitrogen source, and identified as homologous to Achromobacter piechaudii based on morphological and biochemical characteristics, partial 16S rDNA sequence and phylogenetic analysis. Strain E6S showed high level of resistance to various metals (Cd, Zn, and Pb). Besides utilizing ACC, strain E6S exhibited plant beneficial traits, such as solubilization of phosphate and production of indole-3-acetic acid. Inoculation with E6S significantly increased the bioavailability of Cd, Zn, and Pb in soil. In addition, bacterial cells bound considerable amounts of metal ions in the following order: Zn > Cd >Pb. Inoculation of E6S significantly stimulated plant biomass, uptake and bioaccumulation of Cd, Zn, and Pb. However, E6S greatly reduced the root to shoot translocation of Cd and Zn, indicating that bacterial inoculation assisted the host plant to uptake and store heavy metals in its root system. Inoculation with the endophytic bacterium E6S homologous to A. piechaudii can improve phytostabilization of metalliferous soils due to its effective ability to enhance in situ metal rhizoaccumulation in plants. PMID:26870079

  14. 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.

  15. Nickel and manganese transfer from soil to plant in lateritic mining soils from New Caledonia

    NASA Astrophysics Data System (ADS)

    Pouschat, P.; Rose, J.; Alliot, I.; Dominici, C.; Keller, C.; Laffont-Schwob, I.; Olivi, L.; Ambrosi, J.-P.

    2009-04-01

    New Caledonian ferritic soils (more than 50 % of iron) are naturally rich in metals (chromium, nickel, cobalt, and manganese), deficient in major nutrients (nitrogen, phosphorous, and potassium), and unbalanced for the calcium/magnesium ratio. Under these particular ecological conditions, New Caledonia, recognized as a hot-spot of biodiversity, is a natural laboratory to study and understand the adaptation strategies of plants to metalliferous soils, and particularly the tolerance and (hyper)accumulation of metals by plants. Moreover, understanding such mechanisms is essential to develop rehabilitation or phytoremediation techniques for polluted soils, as well as phytomining techniques. Thus, in order to understand the soil - plant relationship and metal mobility along a toposequence in a future nickel mining massif, field experiments were conducted in an isolated ultramafic massif of New Caledonia. Several plant species of two endemic and frequent plant genera were chosen: Tristaniopsis guillainii and T. calobuxus (Myrtaceae), and Phyllanthus serpentinus and P. favieri (Euphorbiaceae), because of their nickel and/or manganese accumulating or hyperaccumulating nature. Leaves, twigs, and roots of all plants were collected along the soil sequence and their associated rhizospheric and bulk soils were sampled. Next, a series of characterization techniques were adapted and then coupled to cryogenics. The combined use of those multiple techniques (cryo-microtomy, cryo-SEM, µXRF, cryo-XAS, and soil characterization) allowed to study co-location and speciation of nickel and manganese in the different plant organs and soils (rhizospheric and bulk). Bioaccumulated nickel and manganese had different distribution patterns. In leaves, Ni accumulated in non photosynthetic tissues (e.g. epidermis) whereas Mn preferentially accumulated in mesophyll whatever the plant species. Nevertheless, in spite of a different speciation in soils, nickel and manganese were both found as similar divalent organometallic complexes in the different plant parts.

  16. Element accumulation patterns of deciduous and evergreen tree seedlings on acid soils: implications for sensitivity to manganese toxicity.

    PubMed

    St Clair, Samuel B; Lynch, Jonathan P

    2005-01-01

    Foliar nutrient imbalances, including the hyperaccumulation of manganese (Mn), are correlated with symptoms of declining health in sensitive tree species growing on acidic forest soils. The objectives of this study were to: (1) compare foliar nutrient accumulation patterns of six deciduous (sugar maple (Acer saccharum Marsh.), red maple (Acer rubrum L.), red oak (Quercus rubra L.), white oak (Quercus alba L.), black cherry (Prunus serotina Ehrh.) and white ash (Fraxinus americana L.)) and three evergreen (eastern hemlock (Tsuga canadensis L.), white pine (Pinus strobus L.) and white spruce (Picea glauca (Moench) Voss.)) tree species growing on acidic forest soils; and (2) examine how leaf phenology and other traits that distinguish evergreen and deciduous tree species influence foliar Mn accumulation rates and sensitivity to excess Mn. For the first objective, leaf samples of seedlings from five acidic, non-glaciated field sites on Pennsylvania's Allegheny Plateau were collected and analyzed for leaf element concentrations. In a second study, we examined growth and photosynthetic responses of seedlings exposed to excess Mn in sand culture. In field samples, Mn in deciduous foliage hyperaccumulated to concentrations more than twice as high as those found in evergreen needles. Among species, sugar maple was the most sensitive to excess Mn based on growth and photosynthetic measurements. Photosynthesis in red maple and red oak was also sensitive to excess Mn, whereas white oak, black cherry, white ash and the three evergreen species were tolerant of excess Mn. Among the nine species, relative rates of photosynthesis were negatively correlated with foliar Mn concentrations, suggesting that photosynthetic sensitivity to Mn is a function of its rate of accumulation in seedling foliage. PMID:15519989

  17. 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.

  18. Bacterially Induced Weathering of Ultramafic Rock and Its Implications for Phytoextraction

    PubMed Central

    Kidd, Petra; Kuffner, Melanie; Prieto-Fernández, Ángeles; Hann, Stephan; Monterroso, Carmela; Sessitsch, Angela; Wenzel, Walter; Puschenreiter, Markus

    2013-01-01

    The bioavailability of metals in soil is often cited as a limiting factor of phytoextraction (or phytomining). Bacterial metabolites, such as organic acids, siderophores, or biosurfactants, have been shown to mobilize metals, and their use to improve metal extraction has been proposed. In this study, the weathering capacities of, and Ni mobilization by, bacterial strains were evaluated. Minimal medium containing ground ultramafic rock was inoculated with either of two Arthrobacter strains: LA44 (indole acetic acid [IAA] producer) or SBA82 (siderophore producer, PO4 solubilizer, and IAA producer). Trace elements and organic compounds were determined in aliquots taken at different time intervals after inoculation. Trace metal fractionation was carried out on the remaining rock at the end of the experiment. The results suggest that the strains act upon different mineral phases. LA44 is a more efficient Ni mobilizer, apparently solubilizing Ni associated with Mn oxides, and this appeared to be related to oxalate production. SBA82 also leads to release of Ni and Mn, albeit to a much lower extent. In this case, the concurrent mobilization of Fe and Si indicates preferential weathering of Fe oxides and serpentine minerals, possibly related to the siderophore production capacity of the strain. The same bacterial strains were tested in a soil-plant system: the Ni hyperaccumulator Alyssum serpyllifolium subsp. malacitanum was grown in ultramafic soil in a rhizobox system and inoculated with each bacterial strain. At harvest, biomass production and shoot Ni concentrations were higher in plants from inoculated pots than from noninoculated pots. Ni yield was significantly enhanced in plants inoculated with LA44. These results suggest that Ni-mobilizing inoculants could be useful for improving Ni uptake by hyperaccumulator plants. PMID:23793627

  19. 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.

  20. 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.

  1. 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.

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

    PubMed Central

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

    2015-01-01

    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

  3. Growth responses of three ornamental plants to Cd and Cd-Pb stress and their metal accumulation characteristics.

    PubMed

    Liu, Jia-nv; Zhou, Qi-xing; Sun, Ting; Ma, Lena Q; Wang, Song

    2008-02-28

    Up to now, there was no document on ornamental plants that had been applied to phytoremediation, which can remedy contaminated environment and beautify it at the same time. Thus, the growth responses and possible phytoremediation ability of three ornamental plants selected from the previous preliminary experiments were further examined under single Cd or combined Cd-Pb stress. The results showed that these tested plants had higher tolerance to Cd and Pb contamination and could effectively accumulate the metals, especially for Calendula officinalis and Althaea rosea. For C. officinalis, it grew normally in soils containing 100 mg kg(-1) Cd without suffering phytotoxicity, and the Cd concentration in the roots was up to 1084 mg kg(-1) while the Cd concentration in the shoots was 284 mg kg(-1). For A. rosea, the Cd accumulation in the shoots was higher than that in the roots when the Cd concentration in soils was <100 mg kg(-1), and reached 100 mg kg(-1) as the criteria of a Cd hyperaccumulator when the Cd concentration in soils was 100 mg kg(-1). Their accumulation and tolerance to Cd and Pb were further demonstrated through the hydroponic-culture method. And A. rosea had a great potential as a possible Cd hyperaccumulator under favorable or induced conditions. Furthermore, the interactive effects of Cd and Pb in the three ornamentals were complicated, not only additive, antagonistic or synergistic, but also related to many factors including concentration combinations of heavy metals, plant species and various parts of plants. Thus, it can be forecasted that this work will provide a new way for phytoremediation of contaminated soils. PMID:17869419

  4. Fast, sensitive, and inexpensive alternative to analytical pigment HPLC: quantification of chlorophylls and carotenoids in crude extracts by fitting with Gauss peak spectra.

    PubMed

    Kpper, Hendrik; Seibert, Sven; Parameswaran, Aravind

    2007-10-15

    Quantification of pigments in complex mixtures is an important task in the physiology of photosynthetic organisms, because pigment composition differs depending on the species, tissue, and physiological state. Currently available methods, however, are either limited to very few pigments (classical UV/vis spectroscopic methods), or they are time-consuming, labor intensive, or costly (e.g., HPLC). Here we describe a UV/vis spectrophotometric method that is capable of a rapid (approximately 1 min/sample) and inexpensive (<1 euro/sample) quantification of more than a dozen pigments in a crude extract, which means it is suitable for high-throughput screening applications. A detection limit of <1 pmol for each pigment allows for determining the pigment composition in only 0.5 microg of lyophilized leaves or algae. The method is based on the description of each pigment spectrum by a series of Gaussian peaks. A sample spectrum is then fitted by a linear combination of these "Gauss peak spectra" including an automatic correction of wavelength inaccuracy, baseline instability, sample turbidity, and effects of temperature/water content. Here we present the Gauss peak spectra from 350 to 750 nm for acetone solutions of all chlorophyll and carotenoid derivatives that are abundant (including conditions of Cd, Cu, or Zn stress) in leaves of higher plants, Euglena, brown algae, and various cyanobacteria like Anabaena and Trichodesmium: [Mg]-Chl a, b, c1, c2; pheophytin a, b; [Cd]-Chl a, b; [Cu]-Chl a, b; [Zn]-Chl a, b; antheraxanthin, aurochrome, beta-carotene, beta-cryptoxanthin, cis- and trans-canthaxanthin, diadinochrome (=diadinoxanthin 5,6-epoxide), cis- and trans-diadinoxanthin, diatoxanthin, cis- and trans-echinenone, fucoxanthin, lutein, myxoxanthophyll, neoxanthin, violaxanthin, and all three stereoisomers of zeaxanthin in acetone. We present extensive tests of our new quantification method for determining optimal and limiting conditions of its performance and for comparison with previous methods. Finally, we show application examples for Thlaspi fendleri (Chlorophyta), Euglena gracilisc (Euglenophyta), Ectocarpus siliculosus (Phaeophyta), and Trichodesmium erythraeum IMS101 (cyanobacteria). PMID:17854156

  5. 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

  6. 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.

  7. 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

  8. [Mechanisms of heavy metal cadmium tolerance in plants].

    PubMed

    Zhang, Jun; Shu, Wen-Sheng

    2006-02-01

    Cadmium (Cd) is a strongly phytotoxic heavy metal, which inhibits plant growth and even leads to plant death. The main symptoms of Cd(2+) toxicity to plants are stunting and chlorosis. Plant has developed some functions for Cd(2+) tolerance, which include cell wall binding, chelation with phytochelatins (PCs), compartmentation of Cd(2+) in vacuole, and enrichment in leaf trichomes. However, Cd(2+) tolerance in plant is more likely involved in an integrated network of multiple response processes than several isolated functions cited above. In the network, the processes of sulfur metabolism, antioxidative response, and Cd(2+) transport across plasma and vacuole membrane in plant are closely related with Cd(2+) tolerance in plant. The processes of sulfur uptake, assimilation and sequential sulfur metabolism in plant respond to Cd(2+) stress. The expression of sulfur transporters with varied affinity was changed in different ways under Cd(2+) stress, and the high expression of ATP sulfurylase (APS) and adenosine 5' phosphosulfate reductase (APR), which may help to keep the supply of S(2-) for cysteine (Cys) synthesis. The efficiency of Cys synthesis may function in Cd(2+) detoxification, and the up-regulated expression of Ser acetyltransferase (SAT) and O-acetyl-ser (thiol)-lyase (OASTL) has been found in some Cd(2+) treated plants. Reduced glutathione (GSH) is an important antioxidant and the precursor of PCs, glutamylcysteine synthetase (GCS) and glutathione synthetase (GS) catalyze GSH synthesis from Cys, overexpression of the two enzymes can improve Cd(2+) tolerance in plant. PCs are more important Cd(2+) chelators than metallothioneins (MTs) in plants, and the expression of phytochelatin synthase (PCS) responds to Cd(2+) stress. Plant antioxidative system also contributes to Cd(2+) tolerance. The antioxidative response to Cd(2+)-induced oxidative stress varies in different plants and tissues and is also Cd(2+) concentration dependent, and the Cd hyperaccumulator plants show strong tolerance to oxidative stress. Some genes encoded metal transporters with Cd(2+) substrate specificity at plasma and vacuole membranes, which have been isolated and characterized in recent years. These genes play critical roles in Cd(2+) translocation, allocation, and compartmentation in plants. Despite the great progresses made in the field in recent years, there are still some issues which need further exploration, such as the detail of signal transduction and the responses of gene regulation to Cd(2+), the rhizosphere activation and root adsorption to soil Cd(2+), Cd(2+) trafficking in xylem and phloem, Cd(2+) translocation to fruit and seed, and the possible presence of a high-affinity Cd(2+) transporter in Cd hyperaccumulators. PMID:16477124

  9. A field study on phytoremediation of a lead-contaminated soil by Eucalyptus globulus in an abandoned mine site - Alagoa, Portugal

    NASA Astrophysics Data System (ADS)

    Gerardo, R.; Kikuchi, R.

    2009-04-01

    Current engineering-based technologies used to clean up soils are very costly and need lots of work. Phytoremediation is the use of plants to remove pollutants (i.e. heavy metals) from the environment or render them harmless. In the phytoremediation process several plant species can be used to reduce the concentrations of heavy metals in contaminated soils to environmentally acceptable levels. The idea of using rare plants which hyperaccumulate metals to selectively remove and recycle excessive soil metals has increasingly been examined as a potential practical and more cost effective technology than soil replacement, solidification, or washing strategies presently used. However, most hyperaccumulator species are not suitable for phytoremediation application in the field due to their small biomass and slow growth. Cultivation of woody plants in contaminated soils has showed potential for use in phytoremediation but also it provides aesthetic improvement in the field. In this study we studied the possibility of using the approach of phytoremediation of lead by Eucalyptus globulus in a lead-contaminated soil from an abandoned mine. Although Eucalytpus globulus prefer good ecological conditions in humid temperate climates, there are few studies that have showed their great potential in contaminated areas and important biomonitors of environmental quality. A test field was set up in an abandoned mine site (Alagoa, Portugal) in order to investigate the feasibility of phytoremediation of lead by Eucalyptus globulus. The field soil was characterized as follows: humus - 2.56-7.08%, pH in the soil water - 4.50-5.10, silte - 18-15% and total Pb - 67-239 mg/kg. The soils in some areas exceed the critical value (150 mg/kg) according with Portuguese law. Eucalytus globulus growing on the abandoned mine, contaminated with lead was studied. The results of shoots sample analysis (n = 15) show the total Pb levels of 0.170-0.093 mg/kg in the stem and 2.94-5.14 mg/kg in the leaves. The results obtain from this work suggest potential indicators for use of Eucalytus globulus in mining areas. Also the presence in the field of several generations of Eucalytus globulus and the existence of young plants near the main gallery suggest good adaptation in lead-contaminated soil.

  10. 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

  11. Capacity of the aquatic fern (Salvinia minima Baker) to accumulate high concentrations of nickel in its tissues, and its effect on plant physiological processes.

    PubMed

    Fuentes, Ignacio I; Espadas-Gil, Francisco; Talavera-May, Carlos; Fuentes, Gabriela; Santamara, Jorge M

    2014-10-01

    An experiment was designed to assess the capacity of Salvinia minima Baker to uptake and accumulate nickel in its tissues and to evaluate whether or not this uptake can affect its physiology. Our results suggest that S. minima plants are able to take up high amounts of nickel in its tissues, particularly in roots. In fact, our results support the idea that S. minima might be considered a hyper-accumulator of nickel, as it is able to accumulate 16.3 mg g(-1) (whole plant DW basis). Our results also showed a two-steps uptake pattern of nickel, with a fast uptake of nickel at the first 6 to 12h of being expose to the metal, followed by a slow take up phase until the end of the experiment at 144 h. S. minima thus, may be considered as a fern useful in the phytoremediation of residual water bodies contaminated with this metal. Also from our results, S. minima can tolerate fair concentrations of the metal; however, at concentrations higher than 80 ?M Ni (1.5 mg g(-1) internal nickel concentration), its physiological performance can be affected. For instance, the integrity of cell membranes was affected as the metal concentration and exposure time increased. The accumulation of high concentrations of internal nickel did also affect photosynthesis, the efficiency of PSII, and the concentration of photosynthetic pigments, although at a lower extent. PMID:25019564

  12. 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.

  13. Aluminum induced metabolic responses in two tea cultivars.

    PubMed

    Xu, Qingshan; Wang, Yu; Ding, Zhaotang; Song, Lubin; Li, Yusheng; Ma, Dexin; Wang, Yi; Shen, Jiazhi; Jia, Sisi; Sun, Haiwei; Zhang, Hong

    2016-04-01

    Tea [Camellia sinensis (L.)], is an aluminum (Al(3+)) hyperaccumulator plant and grows well in acid soils. In the present study, roots of two tea cultivars, JHC and YS were treated with different concentrations of Al(3+). After treatments, the root length, dry matter, root activity and chlorophyll content (SPAD value) of JHC had greater increase than that of YS. We also detected metabolic changes of two varieties using GC-MS method. Comparison between two cultivars indicated that shikimic pathway was more enhanced in YS roots by Al(3+) with higher levels of catechine, quinic acid and shikimic acid. While, more active amino acid synthesis was found in JHC roots and JHC leaves remained the higher level contents of metabolites related to cysteine synthesis. The comparison also showed that a large amount of sugar alcohols were accumulated in roots of two varieties, whereas most of them were reduced in YS leaves. Other well-known ligands, such as phosphoric acid and malic acid were observed in two cultivars that showed significantly altered abundances under Al(3+) treatments. The results indicated that Al(3+) adaptation of two cultivars may be correlated with their differential metabolism of amino acids, sugars and shikimic acids. PMID:26895429

  14. Pilot-scale demonstration of phytofiltration for treatment of arsenic in New Mexico drinking water.

    PubMed

    Elless, Mark P; Poynton, Charissa Y; Willms, Cari A; Doyle, Mike P; Lopez, Alisa C; Sokkary, Dale A; Ferguson, Bruce W; Blaylock, Michael J

    2005-10-01

    Arsenic contamination of drinking water poses serious health risks to millions of people worldwide. To reduce such risks, the United States Environmental Protection Agency recently lowered the Maximum Contaminant Level for arsenic in drinking water from 50 to 10 microgL(-1). The majority of water systems requiring compliance are small systems that serve less than 10,000 people. Current technologies used to clean arsenic-contaminated water have significant drawbacks, particularly for small treatment systems. In this pilot-scale demonstration, we investigated the use of arsenic-hyperaccumulating ferns to remove arsenic from drinking water using a continuous flow phytofiltration system. Over the course of a 3-month demonstration period, the system consistently produced water having an arsenic concentration less than the detection limit of 2 microgL(-1), at flow rates as high as 1900 L day(-1) for a total treated water volume of approximately 60,000 L. Our results demonstrate that phytofiltration provides the basis for a solar-powered hydroponic technique to enable small-scale cleanup of arsenic-contaminated drinking water. PMID:16135379

  15. 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?

  16. Betula pendula: A Promising Candidate for Phytoremediation of TCE in Northern Climates.

    PubMed

    Lewis, Jeffrey; Qvarfort, Ulf; Sjstrm, 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

  17. Anion Channel Inhibitor NPPB-Inhibited Fluoride Accumulation in Tea Plant (Camellia sinensis) Is Related to the Regulation of Ca(2+), CaM and Depolarization of Plasma Membrane Potential.

    PubMed

    Zhang, Xian-Chen; Gao, Hong-Jian; Yang, Tian-Yuan; Wu, Hong-Hong; Wang, Yu-Mei; Zhang, Zheng-Zhu; Wan, Xiao-Chun

    2016-01-01

    Tea plant is known to be a hyper-accumulator of fluoride (F). Over-intake of F has been shown to have adverse effects on human health, e.g., dental fluorosis. Thus, understanding the mechanisms fluoride accumulation and developing potential approaches to decrease F uptake in tea plants might be beneficial for human health. In the present study, we found that pretreatment with the anion channel inhibitor NPPB reduced F accumulation in tea plants. Simultaneously, we observed that NPPB triggered Ca(2+) efflux from mature zone of tea root and significantly increased relative CaM in tea roots. Besides, pretreatment with the Ca(2+) chelator (EGTA) and CaM antagonists (CPZ and TFP) suppressed NPPB-elevated cytosolic Ca(2+) fluorescence intensity and CaM concentration in tea roots, respectively. Interestingly, NPPB-inhibited F accumulation was found to be significantly alleviated in tea plants pretreated with either Ca(2+) chelator (EGTA) or CaM antagonists (CPZ and TFP). In addition, NPPB significantly depolarized membrane potential transiently and we argue that the net Ca(2+) and H⁺ efflux across the plasma membrane contributed to the restoration of membrane potential. Overall, our results suggest that regulation of Ca(2+)-CaM and plasma membrane potential depolarization are involved in NPPB-inhibited F accumulation in tea plants. PMID:26742036

  18. Germin-like protein 2 gene promoter from rice is responsive to fungal pathogens in transgenic potato plants.

    PubMed

    Munir, Faiza; Hayashi, Satomi; Batley, Jacqueline; Naqvi, Syed Muhammad Saqlan; Mahmood, Tariq

    2016-01-01

    Controlled transgene expression via a promoter is particularly triggered in response to pathogen infiltration. This is significant for eliciting disease-resistant features in crops through genetic engineering. The germins and germin-like proteins (GLPs) are known to be associated with plant and developmental stages. The 1107-bp Oryza sativa root GLP2 (OsRGLP2) gene promoter fused to a β-glucuronidase (GUS) reporter gene was transformed into potato plants through an Agrobacterium-mediated transformation. The OsRGLP2 promoter was activated in response to Fusarium solani (Mart.) Sacc. and Alternaria solani Sorauer. Quantitative real-time PCR results revealed 4-5-fold increase in promoter activity every 24 h following infection. There was a 15-fold increase in OsRGLP2 promoter activity after 72 h of F. solani (Mart.) Sacc. treatment and a 12-fold increase observed with A. solani Sorauer. Our results confirmed that the OsRGLP2 promoter activity was enhanced under fungal stress. Furthermore, a hyperaccumulation of H2O2 in transgenic plants is a clear signal for the involvement of OsRGLP2 promoter region in the activation of specific genes in the potato genome involved in H2O2-mediated defense response. The OsRGLP2 promoter evidently harbors copies of GT-I and Dof transcription factors (AAAG) that act in response to elicitors generated in the wake of pathogen infection. PMID:26277722

  19. 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

  20. Aluminium stress disrupts metabolic performance of Plantago almogravensis plantlets transiently.

    PubMed

    Grevenstuk, Toms; Moing, Annick; Maucourt, Mickal; 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

  1. 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 (50.2h) 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

  2. Metal accumulation in wild plants surrounding mining wastes.

    PubMed

    Gonzlez, R Carrillo; Gonzlez-Chvez, M C A

    2006-11-01

    Four sites were selected for collection of plants growing on polluted soil developed on tailings from Ag, Au, and Zn mines at the Zacatecas state in Mexico. Trace element concentrations varied between sites, the most polluted area was at El Bote mine near to Zacatecas city. The ranges of total concentration in soil were as follows: Cd 11-47, Ni 19-26, Pb 232-695, Mn 1132-2400, Cu 134-186 and Zn 116-827 mg kg(-1) air-dried soil weight. All soil samples had concentrations above typical values for non-polluted soils from the same soil types (Cd 0.6+/-0.3, Ni 52+/-4, Pb 41+/-3mg kg(-1)). However, for the majority of samples the DTPA-extractable element concentrations were less than 10% of the total. Some of the wild plants are potentially metal tolerant, because they were able to grow in highly polluted substrates. Plant metal analysis revealed that most species did not translocate metals to their aerial parts, therefore they behave as excluder plants. Polygonum aviculare accumulated Zn (9236 mg kg(-1)) at concentrations near to the criteria for hyperaccumulator plants. Jatropha dioica also accumulated high Zn (6249 mg kg(-1)) concentrations. PMID:16631286

  3. Compound amino acids added in media improved Solanum nigrum L. phytoremediating CD-PAHS contaminated soil.

    PubMed

    Wei, Shuhe; Bai, Jiayi; Yang, Chuanjie; Zhang, Qianru; Knorrm, Klaus-Holger; Zhan, Jie; Gao, Qianhui

    2016-04-01

    Cd hyperaccumulator Solanum nigrum L. was a promising plant used to simultaneously remediate Cd-PAHs combined pollution soil through its extra accumulation capacity and rhizosphere degradation. This article compared the strengthening remediation role of cysteine (Cys), glycine (Gly) and glutamic acid (Glu) with EDTA and TW80. The results showed that the addition of 0.03 mmol L(-1) Cys, Gly, and Glu didn't significantly impact (p < 0.05) shoot biomass of S. nigrum, but obviously increased Cd concentration. Therefore, Cd capacity (µg pot(-1)) in shoots of S. nigrum was significantly increased (p < 0.05) by 37.7% compared to the control without reagent added. At the meantime, the PAHs degradation ratio in rhizoshpere was increased by 34.5%. Basically, the improving role of Cys, Gly, and Glu was higher than EDTA and TW80. The main reasons of enhanced the accumulation of S. nigrum to Cd might lie in the addition of Cys, Gly, and Glu which reduced pH and increased extractable Cd concentration in rhizosphere and phytochelatines (PCs) concentration in leaves. As for the degradation of PAHs in rhizosphere, increased microorganism number might be play important role. PMID:26515779

  4. 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

  5. Inhibition of angiogenesis by selective estrogen receptor modulators through blockade of cholesterol trafficking rather than estrogen receptor antagonism.

    PubMed

    Shim, Joong Sup; Li, Ruo-Jing; Lv, Junfang; Head, Sarah A; Yang, Eun Ju; Liu, Jun O

    2015-06-28

    Selective estrogen receptor modulators (SERM) including tamoxifen are known to inhibit angiogenesis. However, the underlying mechanism, which is independent of their action on the estrogen receptor (ER), has remained largely unknown. In the present study, we found that tamoxifen and other SERM inhibited cholesterol trafficking in endothelial cells, causing a hyper-accumulation of cholesterol in late endosomes/lysosomes. Inhibition of cholesterol trafficking by tamoxifen was accompanied by abnormal subcellular distribution of vascular endothelial growth factor receptor-2 (VEGFR2) and inhibition of the terminal glycosylation of the receptor. Tamoxifen also caused perinuclear positioning of lysosomes, which in turn trapped the mammalian target of rapamycin (mTOR) in the perinuclear region of endothelial cells. Abnormal distribution of VEGFR2 and mTOR and inhibition of VEGFR2 and mTOR activities by tamoxifen were significantly reversed by addition of cholesterol-cyclodextrin complex to the culture media of endothelial cells. Moreover, high concentrations of tamoxifen inhibited endothelial and breast cancer cell proliferation in a cholesterol-dependent, but ER-independent, manner. Together, these results unraveled a previously unrecognized mechanism of angiogenesis inhibition by tamoxifen and other SERM, implicating cholesterol trafficking as an attractive therapeutic target for cancer treatment. PMID:25799952

  6. The Tolerance and Accumulation of Miscanthus Sacchariflorus (maxim.) Benth., an Energy Plant Species, to Cadmium.

    PubMed

    Zhang, Jie; Yang, Shiyong; Huang, Yongjie; Zhou, Shoubiao

    2015-01-01

    Miscanthus sacchariflorus (Maxim.) Benth. is a metallophyte suitable for the phytoremediation of mine wastes. The tolerance and accumulation of M. sacchariflorus to cadmium was studied by pot experiments. The results showed that O2- generation rate, plasma membrane permeability and MDA content of M. sacchariflorus leaves increased with increasing Cd concentrations in soil, but significant effect was only observed when Cd concentrations were ?50 mgkg(-1). SOD and POD activities increased initially but decreased later on, whereas CAT activity only increased significantly at higher Cd concentrations, 50-100 mgkg(-1). The content of photosynthetic pigment and growth of M. sacchariflorus were both not significantly affected when Cd concentration was ?25 mgkg(-1). In contrast, both parameters were significantly affected when Cd concentration was ?50 mgkg(-1). M. sacchariflorus could accumulate much Cd, but most of the Cd assimilated was retained in the belowground part, suggesting that M. sacchariflorus has poor ability to translocate Cd to the aboveground part. Our results suggested that although M. sacchariflorus was not a hyper-accumulator, it has a strong capacity to tolerate and stabilize the Cd. Therefore, M. sacchariflorus has a certain potential in the phytostabilization of Cd-contaminated soils. PMID:25747240

  7. Lipid body accumulation alters calcium signaling dynamics in immune cells.

    PubMed

    Greineisen, William E; Speck, Mark; Shimoda, Lori M N; Sung, Carl; Phan, Nolwenn; Maaetoft-Udsen, Kristina; Stokes, Alexander J; Turner, Helen

    2014-09-01

    There is well-established variability in the numbers of lipid bodies (LB) in macrophages, eosinophils, and neutrophils. Similarly to the steatosis observed in adipocytes and hepatocytes during hyperinsulinemia and nutrient overload, immune cell LB hyper-accumulate in response to bacterial and parasitic infection and inflammatory presentations. Recently we described that hyperinsulinemia, both in vitro and in vivo, drives steatosis and phenotypic changes in primary and transformed mast cells and basophils. LB reach high numbers in these steatotic cytosols, and here we propose that they could dramatically impact the transcytoplasmic signaling pathways. We compared calcium release and influx responses at the population and single cell level in normal and steatotic model mast cells. At the population level, all aspects of Fc?RI-dependent calcium mobilization, as well as activation of calcium-dependent downstream signaling targets such as NFATC1 phosphorylation are suppressed. At the single cell level, we demonstrate that LB are both sources and sinks of calcium following Fc?RI cross-linking. Unbiased analysis of the impact of the presence of LB on the rate of trans-cytoplasmic calcium signals suggest that LB enrichment accelerates calcium propagation, which may reflect a Bernoulli effect. LB abundance thus impacts this fundamental signaling pathway and its downstream targets. PMID:25016314

  8. Heavy metal phytoextraction by Sedum alfredii is affected by continual clipping and phosphorus fertilization amendment.

    PubMed

    Huang, Huagang; Li, Tingqiang; Gupta, D K; He, Zhenli; Yang, Xiao-E; Ni, Bingnan; Li, Mao

    2012-01-01

    Improving the efficacy of phytoextraction is critical for its successful application in metal contaminated soils. Mineral nutrition affects plant growth and metal absorption and subsequently the accumulation of heavy metal through hyper-accumulator plants. This study assessed the effects of di-hydrogen phosphates (KH2PO4, Ca(H2PO4)2, NaH2PO4 and NH4H2PO4) application at three levels (22, 88 and 352 mg P/kg soil) on Sedum alfredii growth and metal uptake by three consecutive harvests on aged and Zn/Cd combined contaminated paddy soil. The addition of phosphates (P) significantly increased the amount of Zn taken up by S. alfredii due to increased shoot Zn concentration and dry matter yield (DMY) (P < 0.05). The highest phytoextraction of Zn and Cd was observed in KH2PO4 and NH4H2PO4 treatment at 352 mg P/kg soil. The amount of Zn removed by phytoextraction increased in the order of 1st clipping < 2nd clipping < 3rd clipping, and for Cd extraction the order was 2nd clipping < 1st clipping < 3rd clipping. These results indicate that the application of P fertilizers coupled with multiple cuttings can enhance the removal of Zn and Cd from contaminated soils by S. alfredii, thus shortening the time needed for accomplishing remediation goals. PMID:22655349

  9. Phytotoxicity of cobalt ions on the duckweed Lemna minor - Morphology, ion uptake, and starch accumulation.

    PubMed

    Sree, K Sowjanya; Keresztes, ron; 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

  10. [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

  11. 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.

  12. The CRR1 nutritional copper sensor in Chlamydomonas contains two distinct metal-responsive domains.

    PubMed

    Sommer, Frederik; Kropat, Janette; Malasarn, Davin; Grossoehme, Nicholas E; Chen, Xiaohua; Giedroc, David P; Merchant, Sabeeha S

    2010-12-01

    Copper response regulator 1 (CRR1), an SBP-domain transcription factor, is a global regulator of nutritional copper signaling in Chlamydomonas reinhardtii and activates genes necessary during periods of copper deficiency. We localized Chlamydomonas CRR1 to the nucleus in mustard (Sinapis alba) seedlings, a location consistent with its function as a transcription factor. The Zn binding SBP domain of CRR1 binds copper ions in vitro. Cu(I) can replace Zn(II), but the Cu(II) form is unstable. The DNA binding activity is inhibited in vitro by Cu(II) or Hg(II) ions, which also prevent activation of transcription in vivo, but not by Co(II) or Ni(II), which have no effect in vivo. Copper inhibition of DNA binding is reduced by mutation of a conserved His residue. These results implicate the SBP domain in copper sensing. Deletion of a C-terminal metallothionein-like Cys-rich domain impacted neither nutritional copper signaling nor the effect of mercuric supplementation, but rendered CRR1 insensitive to hypoxia and to nickel supplementation, which normally activate the copper deficiency regulon in wild-type cells. Strains carrying the crr1-?Cys allele upregulate ZRT genes and hyperaccumulate Zn(II), suggesting that the effect of nickel ions may be revealing a role for the C-terminal domain of CRR1 in zinc homeostasis in Chlamydomonas. PMID:21131558

  13. Two metal-tolerance proteins, MTP1 and MTP4, are involved in Zn homeostasis and Cd sequestration in cucumber cells.

    PubMed

    Migocka, Magdalena; Kosieradzka, Anna; Papierniak, Anna; Maciaszczyk-Dziubinska, Ewa; Posyniak, Ewelina; Garbiec, Arnold; Filleur, Sophie

    2015-02-01

    Metal-tolerance proteins (MTPs) are divalent cation transporters that have been shown to be essential for metal homeostasis and tolerance in model plants and hyperaccumulators. Due to the lack of genomic resources, studies on MTPs in cultivated crops are lacking. Here, we present the first functional characterization of genes encoding cucumber proteins homologous to MTP1 and MTP4 transporters. CsMTP1 expression was ubiquitous in cucumber plants, whereas CsMTP4 mRNA was less abundant and was not detected in the generative parts of the flowers. When expressed in yeast, CsMTP1 and CsMTP4 were able to complement the hypersensitivity of mutant strains to Zn and Cd through the increased sequestration of metals within vacuoles using the transmembrane electrochemical gradient. Both proteins formed oligomers at the vacuolar membranes of yeast and cucumber cells and localized in Arabidopsis protoplasts, consistent with their function in vacuolar Zn and Cd sequestration. Changes in the abundance of CsMTP1 and CsMTP4 transcripts and proteins in response to elevated Zn and Cd, or to Zn deprivation, suggested metal-induced transcriptional, translational, and post-translational modifications of protein activities. The differences in the organ expression and affinity of both proteins to Zn and Cd suggested that CsMTP1 and CsMTP4 may not be functionally redundant in cucumber cells. PMID:25422498

  14. 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 1023mg kg(-1) Cu, 15.2 to 59.2mg kg(-1) Ni, 2.3 to 73.6mg kg(-1) Cd and metals for plants ranged from 0.135 to 283mg kg(-1) Cu, 0.26 to 31.2mg kg(-1) Ni, 0.143 to 277mg 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

  15. Subcellular distribution and chemical forms of cadmium in Impatiens walleriana in relation to its phytoextraction potential.

    PubMed

    Lai, Hung-Yu

    2015-11-01

    Impatiens (Impatiens walleriana) has been shown to be a potential cadmium (Cd) hyperaccumulator, but its mechanisms in accumulation and detoxification have not been reported. Rooted cuttings of Impatiens were planted in artificially Cd-contaminated soils for 50 days with total target concentrations of 0, 10, 20, 40, 80, and 120 mg/kg. The subcellular distribution and chemical forms of Cd in the different organs were analyzed after the pot experiment. Compared with the control group, various Cd treatments affected the growth exhibitions of Impatiens, but most of them were not statistically significant. The Cd accumulation of different organs increased with an increase in the soil Cd concentrations for most of the treatments, and it was in the decreasing order of root>stem>leaf. In the roots of Impatiens, Cd was mainly compartmentalized in the soluble fraction (Fs), which has a high migration capacity and will further translocate to the shoot. The Cd was mainly compartmentalized in the cell wall fraction (Fcw) in the shoots as a mechanism of tolerance. Most of the Cd in the various organs of Impatiens was mainly in the forms of pectate and protein-integrated (FNaCl), whereas a minor portion was a water soluble fraction (FW). The experimental results show that the Cd in the Fs, FW, and FNaCl in the roots of Impatiens had a high mobility and will further translocate to the shoot. They could be used to estimate the Cd accumulated in the shoots of Impatiens. PMID:26133699

  16. 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.

  17. Mining in New Caledonia: environmental stakes and restoration opportunities.

    PubMed

    Losfeld, Guillaume; L'Huillier, Laurent; Fogliani, Bruno; Jaffr, Tanguy; Grison, Claude

    2015-04-01

    New Caledonia is a widely recognised marine and terrestrial biodiversity hot spot. However, this unique environment is under increasing anthropogenic pressure. Major threats are related to land cover change and include fire, urban sprawling and mining. Resulting habitat loss and fragmentation end up in serious erosion of the local biodiversity. Mining is of particular concern due to its economic significance for the island. Open cast mines were exploited there since 1873, and scraping out soil to access ores wipes out flora. Resulting perturbations on water flows and dramatic soil erosion lead to metal-rich sediment transport downstream into rivers and the lagoon. Conflicting environmental and economic aspects of mining are discussed in this paper. However, mining practices are also improving, and where impacts are inescapable ecological restoration is now considered. Past and ongoing experiences in the restoration of New Caledonian terrestrial ecosystems are presented and discussed here. Economic use of the local floristic diversity could also promote conservation and restoration, while providing alternative incomes. In this regard, Ecocatalysis, an innovative approach to make use of metal hyperaccumulating plants, is of particular interest. PMID:25065482

  18. Anion Channel Inhibitor NPPB-Inhibited Fluoride Accumulation in Tea Plant (Camellia sinensis) Is Related to the Regulation of Ca2+, CaM and Depolarization of Plasma Membrane Potential

    PubMed Central

    Zhang, Xian-Chen; Gao, Hong-Jian; Yang, Tian-Yuan; Wu, Hong-Hong; Wang, Yu-Mei; Zhang, Zheng-Zhu; Wan, Xiao-Chun

    2016-01-01

    Tea plant is known to be a hyper-accumulator of fluoride (F). Over-intake of F has been shown to have adverse effects on human health, e.g., dental fluorosis. Thus, understanding the mechanisms fluoride accumulation and developing potential approaches to decrease F uptake in tea plants might be beneficial for human health. In the present study, we found that pretreatment with the anion channel inhibitor NPPB reduced F accumulation in tea plants. Simultaneously, we observed that NPPB triggered Ca2+ efflux from mature zone of tea root and significantly increased relative CaM in tea roots. Besides, pretreatment with the Ca2+ chelator (EGTA) and CaM antagonists (CPZ and TFP) suppressed NPPB-elevated cytosolic Ca2+ fluorescence intensity and CaM concentration in tea roots, respectively. Interestingly, NPPB-inhibited F accumulation was found to be significantly alleviated in tea plants pretreated with either Ca2+ chelator (EGTA) or CaM antagonists (CPZ and TFP). In addition, NPPB significantly depolarized membrane potential transiently and we argue that the net Ca2+ and H+ efflux across the plasma membrane contributed to the restoration of membrane potential. Overall, our results suggest that regulation of Ca2+-CaM and plasma membrane potential depolarization are involved in NPPB-inhibited F accumulation in tea plants. PMID:26742036

  19. 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

  20. 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

  1. 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

  2. Proteomic changes in maize as a response to heavy metal (lead) stress revealed by iTRAQ quantitative proteomics.

    PubMed

    Li, G K; Gao, J; Peng, H; Shen, Y O; Ding, H P; Zhang, Z M; Pan, G T; Lin, H J

    2016-01-01

    Lead (Pb), a heavy metal, has become a crucial pollutant in soil and water, causing not only permanent and irreversible health problems, but also substantial reduction in crop yields. In this study, we conducted proteome analysis of the roots of the non-hyperaccumulator inbred maize line 9782 at four developmental stages (0, 12, 24, and 48 h) under Pb pollution using isobaric tags for relative and absolute quantification technology. A total of 252, 72 and 116 proteins were differentially expressed between M12 (after 12-h Pb treatment) and CK (water-mocked treatment), M24 (after 24-h Pb treatment) and CK, and M48 (after 48-h Pb treatment) and CK, respectively. In addition, 14 differentially expressed proteins were common within each comparison group. Moreover, Cluster of Orthologous Groups enrichment analysis revealed predominance of the proteins involved in posttranslational modification, protein turnover, and chaperones. Additionally, the changes in protein profiles showed a lower concordance with corresponding alterations in transcript levels, indicating important roles for transcriptional and posttranscriptional regulation in the response of maize roots to Pb pollution. Furthermore, enriched functional categories between the successive comparisons showed that the proteins in functional categories of stress, redox, signaling, and transport were highly up-regulated, while those in the functional categories of nucleotide metabolism, amino acid metabolism, RNA, and protein metabolism were down-regulated. This information will help in furthering our understanding of the detailed mechanisms of plant responses to heavy metal stress by combining protein and mRNA profiles. PMID:26909923

  3. Managing the manganese: molecular mechanisms of manganese transport and homeostasis.

    PubMed

    Pittman, Jon K

    2005-09-01

    Manganese (Mn) is an essential metal nutrient for plants. Recently, some of the genes responsible for transition metal transport in plants have been identified; however, only relatively recently have Mn2+ transport pathways begun to be identified at the molecular level. These include transporters responsible for Mn accumulation into the cell and release from various organelles, and for active sequestration into endomembrane compartments, particularly the vacuole and the endoplasmic reticulum. Several transporter gene families have been implicated in Mn2+ transport, including cation/H+ antiporters, natural resistance-associated macrophage protein (Nramp) transporters, zinc-regulated transporter/iron-regulated transporter (ZRT/IRT1)-related protein (ZIP) transporters, the cation diffusion facilitator (CDF) transporter family, and P-type ATPases. The identification of mutants with altered Mn phenotypes can allow the identification of novel components in Mn homeostasis. In addition, the characterization of Mn hyperaccumulator plants can increase our understanding of how plants can adapt to excess Mn, and ultimately allow the identification of genes that confer this stress tolerance. The identification of genes responsible for Mn2+ transport has substantially improved our understanding of plant Mn homeostasis. PMID:16101910

  4. 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

  5. Laboratory Protocol for Measuring the Bioaccumulation of Mercury by Earthworms

    NASA Astrophysics Data System (ADS)

    Steffy, D.; Nichols, A.; McLaughlin, A.

    2007-12-01

    Protocol was developed for a series of laboratory tests to determine if Canadian earthworms ( Lumbricus terrestris) can hyperaccumulate mercury from the soil in which they live. Two batches of 300 hundred worms each were measured for mercury uptake by establishing 3 populations (one control and two of known contamination). Populations were sampled every two weeks. Worm lengths were measured as an indicator of worm age and health. Worm tissue was processed by a modified EPA Method 7470 consisting of freeze drying, vacuum extraction, oxidation and acid extraction of the mercury. Each sample needed 2.000 g dry weight of worm tissue required 5 to 6 worms to be homogenized. Mercury concentration in the extraction fluid was measured by a CETAC M-6100 cold vapor mercury analyzer with an ASX-400 Autosampler having a method detection limit of 0.05 ppb. QA/QC activities such as calibration of instrumentation, spike samples, blank samples, reagent control samples, triplicate samples, and standard samples ensure acurate and precise measurements of mercury levels in tissue samples.

  6. 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

  7. Isolation and N-terminal sequencing of a novel cadmium-binding protein from Boletus edulis

    NASA Astrophysics Data System (ADS)

    Collin-Hansen, C.; Andersen, R. A.; Steinnes, E.

    2003-05-01

    A Cd-binding protein was isolated from the popular edible mushroom Boletus edulis, which is a hyperaccumulator of both Cd and Hg. Wild-growing samples of B. edulis were collected from soils rich in Cd. Cd radiotracer was added to the crude protein preparation obtained from ethanol precipitation of heat-treated cytosol. Proteins were then further separated in two consecutive steps; gel filtration and anion exchange chromatography. In both steps the Cd radiotracer profile showed only one distinct peak, which corresponded well with the profiles of endogenous Cd obtained by atomic absorption spectrophotometry (AAS). Concentrations of the essential elements Cu and Zn were low in the protein fractions high in Cd. N-terminal sequencing performed on the Cd-binding protein fractions revealed a protein with a novel amino acid sequence, which contained aromatic amino acids as well as proline. Both the N-terminal sequencing and spectrofluorimetric analysis with EDTA and ABD-F (4-aminosulfonyl-7-fluoro-2, 1, 3-benzoxadiazole) failed to detect cysteine in the Cd-binding fractions. These findings conclude that the novel protein does not belong to the metallothionein family. The results suggest a role for the protein in Cd transport and storage, and they are of importance in view of toxicology and food chemistry, but also for environmental protection.

  8. Interaction of SOS2 with Nucleoside Diphosphate Kinase 2 and Catalases Reveals a Point of Connection between Salt Stress and H2O2 Signaling in Arabidopsis thaliana?

    PubMed Central

    Verslues, Paul E.; Batelli, Giorgia; Grillo, Stefania; Agius, Fernanda; Kim, Yong-Sig; Zhu, Jianhua; Agarwal, Manu; Katiyar-Agarwal, Surekha; Zhu, Jian-Kang

    2007-01-01

    SOS2, a class 3 sucrose-nonfermenting 1-related kinase, has emerged as an important mediator of salt stress response and stress signaling through its interactions with proteins involved in membrane transport and in regulation of stress responses. We have identified additional SOS2-interacting proteins that suggest a connection between SOS2 and reactive oxygen signaling. SOS2 was found to interact with the H2O2 signaling protein nucleoside diphosphate kinase 2 (NDPK2) and to inhibit its autophosphorylation activity. A sos2-2 ndpk2 double mutant was more salt sensitive than a sos2-2 single mutant, suggesting that NDPK2 and H2O2 are involved in salt resistance. However, the double mutant did not hyperaccumulate H2O2 in response to salt stress, suggesting that it is altered signaling rather than H2O2 toxicity alone that is responsible for the increased salt sensitivity of the sos2-2 ndpk2 double mutant. SOS2 was also found to interact with catalase 2 (CAT2) and CAT3, further connecting SOS2 to H2O2 metabolism and signaling. The interaction of SOS2 with both NDPK2 and CATs reveals a point of cross talk between salt stress response and other signaling factors including H2O2. PMID:17785451

  9. Effect of endophytic fungi on cadmium tolerance and bioaccumulation by Festuca arundinacea and Festuca pratensis.

    PubMed

    Soleimani, Mohsen; Hajabbasi, Mohammad A; Afyuni, Majid; Mirlohi, Aghafakhr; Borggaard, Ole K; Holm, Peter E

    2010-08-01

    Endophytic fungi are a group of fungi that live asymptomatically inside plant tissue. These fungi may increase host plant tolerance to biotic and abiotic stresses. The effect of Neotyphodium endophytes in two grass species (Festuca arundinacea and Festuca pratensis) on cadmium (Cd) tolerance, accumulation and translocation has been our main objective. The plants were grown in a hydroponic system under different Cd concentrations (0, 5, 10, and 20 mg L(-1)) for 6 weeks. They were also grown in soil spiked with different concentrations of Cd (0, 10, 20, and 40 mg kg(-1)) for 2 months. The results from all Cd treatments showed higher biomass production (12-24%) and higher potential to accumulate Cd in roots (6-16%) and shoots (6-20%) of endophyte-infected plants than endophyte-free plants. Cadmium accumulation by plants indicated that the grasses were capable of Cd hyperaccumulation, a property that was augmented after endophyte infection. Maximum photochemical efficiency of photosystem II (Fv/Fm) revealed that Cd stress was significantly reduced in endophyte-infected plants compared to non-infected ones. PMID:21166279

  10. Detection of lead in Zea mays by dual-energy X-ray microtomography at the SYRMEP beamline of the ELETTRA synchrotron and by atomic absorption spectroscopy.

    PubMed

    Reale, Lucia; Kaiser, Jozef; Pace, Loretta; Lai, Antonia; Flora, Francesco; Angelosante Bruno, Antonella; Tucci, Adele; Zuppella, Paola; Mancini, Lucia; Tromba, Giuliana; Ruggieri, Fabrizio; Fanelli, Maria; Malina, Radomir; Liska, Miroslav; Poma, Anna

    2010-06-01

    This study is related to the application of the X-ray dual-energy microradiography technique together with the atomic absorption spectroscopy (AAS) for the detection of lead on Zea mays stem, ear, root, and leaf samples. To highlight the places with lead intake, the planar radiographs taken with monochromatic X-ray radiation in absorption regime with photon energy below and above the absorption edge of a given chemical element, respectively, are analyzed and processed. To recognize the biological structures involved in the intake, the dual-energy images with the lead signal have been compared with the optical images of the same Z. mays stem. The ear, stem, root, and leaf samples have also been analyzed with the AAS technique to measure the exact amount of the hyperaccumulated lead. The AAS measurement revealed that the highest intake occurred in the roots while the lowest in the maize ears and in the leaf. It seems there is a particular mechanism that protects the seeds and the leaves in the intake process. PMID:19953664

  11. From biodiversity to catalytic diversity: how to control the reaction mechanism by the nature of metallophytes.

    PubMed

    Escande, Vincent; Olszewski, Tomasz K; Grison, Claude

    2015-04-01

    Phytoextraction is widely used for the reclamation of degraded sites, particularly to remove trace metals from contaminated soils. Whereas this technique demonstrates several advantages, the biomass resulting from phytoextraction processes is highly enriched in metallic elements and constitutes therefore a problematic waste. We show here that this biomass can be used for the preparation of novel polymetallic extracts, with high potential as catalysts or reagents in organic synthesis. This new concept of ecocatalysis constitutes an innovative recycling of metallic elements whose current known reserves could be exhausted in the coming decades. The ecocatalysts Eco-Zn and Eco-Ni prepared respectively from Zn and Ni hyperaccumulating plants display two distinct chemical reactivities, starting from the same substrates. Eco-Zn led to the formation of esters of commercial interest for the fragrance industry, following a hydro-acyloxy-addition reaction pathway. In contrast, Eco-Ni afforded chlorinated products thank to the hydrochlorination of alkenes. Both ecocatalysts allowed the synthesis of valuable products in high yields through methodologies in line with the spirit of sustainable chemistry. PMID:25172465

  12. The Overlapping Roles of Manganese and Cu/Zn SOD in Oxidative Stress Protection

    PubMed Central

    Reddi, Amit R.; Jensen, Laran T.; Naranuntarat, Amornrat; Rosenfeld, Leah; Leung, Edison; Shah, Rishita; Culotta, Valeria C.

    2009-01-01

    In various organisms, high intracellular manganese provides protection against oxidative damage through unknown pathways. Herein we use a genetic approach in S. cerevisiae to analyze factors that promote manganese as an anti-oxidant in cells lacking Cu/Zn superoxide dismutase (sod1?). Unlike certain bacterial systems [1], oxygen resistance in yeast correlates with high intracellular manganese without a lowering of iron. This manganese for anti-oxidant protection is provided by the Nramp transporters Smf1p and Smf2p, with Smf1p playing a major role. In fact, loss of manganese transport by Smf1p together with loss of the Pmr1p manganese pump is lethal to sod1? cells in spite of normal manganese SOD2 activity. Manganese-phosphate complexes are excellent superoxide dimustase mimics in vitro [2], yet through genetic disruption of phosphate transport and storage, we observed no requirement for phosphate in manganese suppression of oxidative damage. If anything, elevated phosphate correlated with profound oxidative stress in sod1? mutants. The efficacy of manganese as an anti-oxidant was drastically reduced in cells that hyper-accumulate phosphate without effects on MnSOD activity. Non-SOD manganese can provide a critical backup for Cu/Zn SOD1, but only under appropriate physiologic conditions. PMID:18973803

  13. Accumulation of radium in relation to some chemical analogues in Dicranopteris linearis.

    PubMed

    Chao, J H; Chuang, C Y

    2011-01-01

    This study elucidates the uptake and accumulation of radium in the field-growing fern Dicranopteris linearis by relating the radium concentration to some potential chemical analogues, including alkaline earth metals, rare earth elements, and some important heavy metals. Time-dependent accumulation of radium and these chemical analogues for D. linearis were described by the (228)Th/(228)Ra activity ratio, an index for inferring plant age. The correlation between radium and these elements was assessed by statistical analysis and used as a reference to elucidate the uptake and accumulation of radium in relation to the chemical analogues. Analytical and statistical results showed that the concentrations of alkaline earth metals (except for Mg) rare earth elements and some heavy metals in D. linearis increased linearly with plant age. These elements, exhibiting a similar accumulation pattern to radium and significant correlation coefficients with radium, were considered as the chemical analogues to radium. Additionally, the plant/soil concentration ratios (CRs) for radium and most of these analogues in D. linearis exceeded 1, consistent with the definition of hyper-accumulator plants. PMID:20817540

  14. Cryptic adaptive radiation in tropical forest trees in New Caledonia.

    PubMed

    Pillon, Yohan; Hopkins, Helen C F; Rigault, Frédéric; Jaffré, Tanguy; Stacy, Elizabeth A

    2014-04-01

    The causes of the species richness of tropical trees are poorly understood, in particular the roles of ecological factors such as soil composition. The nickel(Ni)-hyperaccumulating tree genus Geissois (Cunoniaceae) from the South-west Pacific was chosen as a model of diversification on different substrates. Here, we investigated the leaf element compositions, spatial distributions and phylogeny of all species of Geissois occurring on New Caledonia. We found that New Caledonian Geissois descended from a single colonist and diversified relatively quickly into 13 species. Species on ultramafic and nonultramafic substrates showed contrasting patterns of leaf element composition and range overlap. Those on nonultramafic substrates were largely sympatric but had distinct leaf element compositions. By contrast, species on ultramafic substrates showed similar leaf element composition, but occurred in many cases exclusively in allopatry. Further, earlier work showed that at least three out of these seven species use different molecules to bind Ni. Geissois qualifies as a cryptic adaptive radiation, and may be the first such example in a lineage of tropical forest trees. Variation in biochemical strategies for coping with both typical and adverse soil conditions may help to explain the diversification and coexistence of tropical forest trees on similar soil types. PMID:24443886

  15. 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

  16. Uptake and reduction of Cr(VI) to Cr(III) by mesquite (Prosopis spp.): chromate-plant interaction in hydroponics and solid media studied using XAS.

    PubMed

    Aldrich, M V; Gardea-Torresdey, J L; Peralta-Videa, J R; Parsons, J G

    2003-05-01

    Chromium (Cr) is a well-established carcinogen that is a contaminant at half of the EPA Superfund sites in the United States. Two separate studies were performed to investigate the possibility that mesquite (Prosopis spp.), which is an indigenous desert plant species, can remove Cr from the environment via active transport systems to the aerial portions of the plant. The first study was performed by growing mesquite on solid media (agar) at Cr(VI) concentrations of 75 and 125 ppm. The accumulation found in the leaves under the present conditions indicated that mesquite could be classified as a hyperaccumulator of chromium. The second study was conducted to investigate the differences between the type of Cr ligand involved in Cr uptake with agar and hydroponic cultures. We used X-ray absorption spectroscopy (XAS) to determine the mechanisms involved in the uptake and binding of Cr(VI) in live mesquite tissue. The XAS results for this study showed that some of the supplied Cr(VI) was uptaken by the mesquite roots; however, the data analyses of the plant tissues demonstrated that it was fully reduced to Cr(III) in the leaf tissues. Experiments are currently being performed to evaluate the behavior of the Mesquite plant using lower Cr concentrations. PMID:12775058

  17. Cadmium tolerance and accumulation of Elsholtzia argyi origining from a zinc/lead mining site - a hydroponics experiment.

    PubMed

    Li, Siliang; Wang, Fengping; Ru, Mei; Ni, Wuzhong

    2014-01-01

    In this study, a hydroponics experiment was conducted to investigate the characteristics of Cd tolerance and accumulation of Elsholtzia argyi natively growing on the soil with high levels of heavy metals in a Zn/Pb mining site. Seedlings of E. argyi grown for 4 weeks and then were treated with 0(CK), 5,10,15, 20, 25, 30, 40, 50,100 umM Cd for 21 days. Each treatment had three replications. No visual toxic symptoms on shoots of E. argyi were observed at Cd level < or = 50 muM. The results indicated that the dry biomass of each tissue and the whole plants of the treatments with < or =40 umM cadmium were similar to that of the control, implying that E. argyi was a cadmium tolerant plant. The results also showed that the shoot Cd concentration significantly (P < 0.05) increased with the increase in the Cd level in nutrient solution. The shoot Cd concentration of the treatment with 40 umM Cd was as high as 237.9 mg kg(-1), which was higher than 100 mg kg(-1), normally used as the threshold concentration for identifying the Cd hyperaccumulating plant. It could be concluded that E. argyi was a Cd tolerant and accumulating plant species. PMID:24933916

  18. Effects of cadmium and arsenic on Pteris vittata under hydroponic conditions.

    PubMed

    Drava, Giuliana; Roccotiello, Enrica; Minganti, Vincenzo; Manfredi, Alice; Cornara, Laura

    2012-06-01

    Pteris vittata is known to hyperaccumulate arsenic, and a large number of studies on this fern species can be found in the literature aimed at evaluating its behavior when coexposed to other toxic elements. In the present study, P. vittata was treated with different concentrations of As and/or Cd in a hydroponic system, that is, under complete bioavailability of the elements, with the objective of investigating the effects of these two elements and their interactions. The response of the plant was evaluated by measuring As, Cd, P, and Ca concentrations in different parts of the plant. Moreover, the symptoms of phytotoxicity were assessed in terms of biomass reduction and loss of photosynthetic efficiency related to necrosis of pinnae. The concentrations of As and Cd measured in the fronds and the root system were significantly dependent on the treatment, whereas P and Ca concentrations were not affected. Interaction effects between As and Cd were observed, with maximum toxicity symptoms after treatment with both elements. This could affect the potential use of this fern for phytoremediation. Although As treatment produced a significant effect on leaves (e.g., chlorosis and necrosis), Cd treatment produced a stronger negative impact on plant health, reducing significantly the biomass and photosynthetic efficiency. PMID:22505316

  19. Investigation of biomethylation of arsenic and tellurium during composting.

    PubMed

    Diaz-Bone, Roland A; Raabe, Maren; Awissus, Simone; Keuter, Bianca; Menzel, Bernd; Kppers, Klaus; Widmann, Renatus; Hirner, Alfred V

    2011-05-30

    Though the process of composting features a high microbiological activity, its potential to methylate metals and metalloids has been little investigated so far in spite of the high impact of this process on metal(loid) toxicity and mobility. Here, we studied the biotransformation of arsenic, tellurium, antimony, tin and germanium during composting. Time resolved investigation revealed a highly dynamic process during self-heated composting with markedly differing time patterns for arsenic and tellurium species. Extraordinary high concentrations of up to 150 mg kg(-1) methylated arsenic species as well as conversion rates up to 50% for arsenic and 5% for tellurium were observed. In contrast, little to no conversion was observed for antimony, tin and germanium. In addition to experiments with metal(loid) salts, composting of arsenic hyperaccumulating ferns Pteris vittata and P. cretica grown on As-amended soils was studied. Arsenic accumulated in the fronds was efficiently methylated resulting in up to 8 mg kg(-1) methylated arsenic species. Overall, these studies indicate that metal(loid)s can undergo intensive biomethylation during composting. Due to the high mobility of methylated species this process needs to be considered in organic waste treatment of metal(loid) contaminated waste materials. PMID:21354698

  20. 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

  1. 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

  2. Stability of Tl(III) in the context of speciation analysis of thallium in plants.

    PubMed

    Sadowska, Monika; Biaduń, Ewa; Krasnodębska-Ostręga, 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. 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

  4. Metal binding to the N-terminal cytoplasmic domain of the PIB ATPase HMA4 is required for metal transport in Arabidopsis.

    PubMed

    Laurent, Clmentine; Lekeux, Gilles; Ukuwela, Ashwinie A; Xiao, Zhiguang; Charlier, Jean-Benoit; Bosman, Bernard; Carnol, Monique; Motte, Patrick; Damblon, Christian; Galleni, Moreno; Hanikenne, Marc

    2016-03-01

    PIB ATPases are metal cation pumps that transport metals across membranes. These proteins possess N- and C-terminal cytoplasmic extensions that contain Cys- and His-rich high affinity metal binding domains, which may be involved in metal sensing, metal ion selectivity and/or in regulation of the pump activity. The PIB ATPase HMA4 (Heavy Metal ATPase 4) plays a central role in metal homeostasis in Arabidopsis thaliana and has a key function in zinc and cadmium hypertolerance and hyperaccumulation in the extremophile plant species Arabidopsis halleri. Here, we examined the function and structure of the N-terminal cytoplasmic metal-binding domain of HMA4. We mutagenized a conserved CCTSE metal-binding motif in the domain and assessed the impact of the mutations on protein function and localization in planta, on metal-binding properties in vitro and on protein structure by Nuclear Magnetic Resonance spectroscopy. The two Cys residues of the motif are essential for the function, but not for localization, of HMA4 in planta, whereas the Glu residue is important but not essential. These residues also determine zinc coordination and affinity. Zinc binding to the N-terminal domain is thus crucial for HMA4 protein function, whereas it is not required to maintain the protein structure. Altogether, combining in vivo and in vitro approaches in our study provides insights towards the molecular understanding of metal transport and specificity of metal P-type ATPases. PMID:26797794

  5. 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

  6. Reverse genetic characterization of cytosolic acetyl-CoA generation by ATP-citrate lyase in Arabidopsis.

    PubMed

    Fatland, Beth L; Nikolau, Basil J; Wurtele, Eve Syrkin

    2005-01-01

    Acetyl-CoA provides organisms with the chemical flexibility to biosynthesize a plethora of natural products that constitute much of the structural and functional diversity in nature. Recent studies have characterized a novel ATP-citrate lyase (ACL) in the cytosol of Arabidopsis thaliana. In this study, we report the use of antisense RNA technology to generate a series of Arabidopsis lines with a range of ACL activity. Plants with even moderately reduced ACL activity have a complex, bonsai phenotype, with miniaturized organs, smaller cells, aberrant plastid morphology, reduced cuticular wax deposition, and hyperaccumulation of starch, anthocyanin, and stress-related mRNAs in vegetative tissue. The degree of this phenotype correlates with the level of reduction in ACL activity. These data indicate that ACL is required for normal growth and development and that no other source of acetyl-CoA can compensate for ACL-derived acetyl-CoA. Exogenous malonate, which feeds into the carboxylation pathway of acetyl-CoA metabolism, chemically complements the morphological and chemical alterations associated with reduced ACL expression, indicating that the observed metabolic alterations are related to the carboxylation pathway of cytosolic acetyl-CoA metabolism. The observations that limiting the expression of the cytosolic enzyme ACL reduces the accumulation of cytosolic acetyl-CoA-derived metabolites and that these deficiencies can be alleviated by exogenous malonate indicate that ACL is a nonredundant source of cytosolic acetyl-CoA. PMID:15608338

  7. Uptake and translocation of arsenite by Pteris vittata L.: effects of glycerol, antimonite and silver.

    PubMed

    Mathews, Shiny; Rathinasabapathi, Bala; Ma, Lena Q

    2011-12-01

    AsIII uptake in living cells is through aquaglyceroporin transporters, but it is unknown in arsenic-hyperaccumulator Pteris vittata. We investigated the effects of AsIII analogs glycerol and antimonite (SbIII) at 0-100 mM and aquaporin inhibitor AgNO(3) at 0-0.1 mM on the uptake of 0.1 mM AsIII or AsV by P. vittata over 1-2 h. Glycerol or SbIII didn't impact AsIII or AsV uptake by P. vittata (p < 0.05), with As concentrations in the fronds and roots being 4.4-6.3 and 3.9-6.2 mg/kg. However, 0.01 mM AgNO(3) reduced As concentrations in the fronds and roots by 64% and 58%. Hence, AsIII uptake in P. vittata might be via an aquaporin transporter different from glycerol and SbIII transporters. Further as AsIII analogs and aquaporin inhibitor had no impact on AsV uptake, AsIII and AsV were likely taken up by different transporters in P. vittata. Our results imply a different AsIII transporter in P. vittata from other plants. PMID:21893373

  8. Regulation of growth and antioxidant enzyme activities by 28-homobrassinolide in seedlings of Raphanus sativus L. under cadmium stress.

    PubMed

    Sharma, Indu; Pati, Pratap Kumar; Bhardwaj, Renu

    2010-06-01

    28-Homobrassinolide (28-HBL), a brassinosteroid is reported to play significant role in diverse physiological processes. It induces a range of cellular and adaptive responses to a range of environmental stresses. Cadmium (Cd) is a non-essential metal which alters various physiological processes and generates ROS, which can oxidize biological macromolecules and causes oxidative stress. This stress is generally overcome by the internal antioxidative defense system and stress shielding phytohormones. In this study, effect of 28-HBL was studied on growth and activities of antioxidant enzymes in known hyperaccumulator Raphanus sativus L. (radish) seedlings grown under cadmium (Cd) metal stress. To determine the influence of 28-HBL (0, 10-(11), 10-(9), 10-(7) M) in radish seedlings subjected to Cd (0, 0.5, 1.0, 1.5 mM) stress, the activities of antioxidant enzymes (APOX, CAT, GR, POD and SOD) were analyzed. In addition, length and biomass of radish seedlings was also recorded. Cd toxicity resulted in reduced length, biomass, protein content and activities of antioxidant enzymes. 28-HBL treatments lowered the Cd toxicity by enhancing the activities of antioxidant enzymes, biomass and seedling length. The present study thus suggests a possible role of 28-HBL in amelioration of metal stress by regulating the activities of antioxidant enzymes in radish. PMID:20653289

  9. Purification and characterization of a highly active chromate reductase from endophytic Bacillus sp. DGV19 of Albizzia lebbeck (L.) Benth. actively involved in phytoremediation of tannery effluent-contaminated sites.

    PubMed

    Manikandan, Muthu; Gopal, Judy; Kumaran, Rangarajulu Senthil; Kannan, Vijayaraghavan; Chun, Sechul

    2016-02-17

    Phytoremediation using timber-yielding tree species is considered to be the most efficient method for chromium/tannery effluent-contaminated sites. In this study, we have chosen Albizzia lebbeck, a chromium hyperaccumulator plant, and studied one of its chromium detoxification processes operated by its endophytic bacterial assemblage. Out of the four different groups of endophytic bacteria comprising Pseudomonas, Rhizobium, Bacillus, and Salinicoccus identified from A. lebbeck employed in phytoremediation of tannery effluent-contaminated soil, Bacillus predominated with three species, which exhibited not only remarkable chromium accumulation ability but also high chromium reductase activity. A chromate reductase was purified to homogeneity from the most efficient chromium accumulator, Bacillus sp. DGV 019, and the purified 34.2-kD enzyme was observed to be stable at temperatures from 20C to 60C. The enzyme was active over a wide range of pH values (4.0-9.0). Furthermore, the enzyme activity was enhanced with the electron donors NADH, followed by NADPH, not affected by glutathione and ascorbic acid. Cu(2+) enhanced the activity of the purified enzyme but was inhibited by Zn(2+) and etheylenediamine tetraacetic acid (EDTA). In conclusion, due to its versatile adaptability the chromate reductase can be used for chromium remediation. PMID:26444299

  10. Evaluation of two Brazilian indigenous plants for phytostabilization and phytoremediation of copper-contaminated soils.

    PubMed

    Andreazza, R; Bortolon, L; Pieniz, S; Bento, F M; Camargo, F A O

    2015-11-01

    Indigenous plants have been grown naturally and vigorously in copper contaminated soils. Thus, the aim of this study was to evaluate the phytoremediation ability of two indigenous plants naturally grown in two vineyard soils copper contaminated, and in a copper mining waste. However, it was evaluated the macro and micronutrient uptake and the potential of phytoremediation. So, a greenhouse study was carried out with Bidens pilosa and Plantago lanceolata in samples of vineyard soils (Inceptisol and Mollisol) copper contaminated, and in a copper mining waste. Plant growth, macro and micronutrient up take, tolerance index (TI), translocation factor (TF), metal extraction ratio (MER), bioaccumulation factor (BCF), plant effective number of the shoots (PENs), and plant effective number of the total plant (PENt) were analyzed. Both plants grown in vineyard soils showed high phytomass production and TI. P. lanceolata plants cultivated in the Inceptisol showed the highest copper concentrations in the shoots (142 mg kg-1), roots (964 mg kg-1) and entire plants (1,106 mg kg-1). High levels of copper were phytoaccumulated from the Inceptisol by B. pilosa and P. lanceolata with 3,500 and 2,200 g ha-1 respectively. Both B. pilosa and P. lanceolata plants showed characteristics of high copper hyperaccumulator. Results showed that both species play an important role in the natural copper phytoaccumulation in both vineyard soils contaminated with copper, being important to its phytoremediation. PMID:26675903

  11. A Novel Selenocystine-Accumulating Plant in Selenium-Mine Drainage Area in Enshi, China

    PubMed Central

    Yuan, Linxi; Zhu, Yuanyuan; Lin, Zhi-Qing; Banuelos, Gary; Li, Wei; Yin, Xuebin

    2013-01-01

    Plant samples of Cardamine hupingshanesis (Brassicaceae), Ligulariafischeri (Ledeb.) turcz (Steraceae) and their underlying top sediments were collected from selenium (Se) mine drainage areas in Enshi, China. Concentrations of total Se were measured using Hydride Generation-Atomic Fluorescence Spectrometry (HG-AFS) and Se speciation were determined using liquid chromatography/UV irradiation-hydride generation-atomic fluorescence spectrometry (LC-UV-HG-AFS). The results showed that C. hupingshanesis could accumulate Se to 239±201 mg/kg DW in roots, 316±184 mg/kg DW in stems, and 380±323 mg/kg DW in leaves, which identifies it as Se secondary accumulator. Particularly, it could accumulate Se up to 1965±271 mg/kg DW in leaves, 1787±167 mg/kg DW in stem and 4414±3446 mg/kg DW in roots, living near Se mine tailing. Moreover, over 70% of the total Se accumulated in C. hupingshanesis were in the form of selenocystine (SeCys2), increasing with increased total Se concentration in plant, in contrast to selenomethionine (SeMet) in non-accumulators (eg. Arabidopsis) and secondary accumulators (eg. Brassica juncea), and selenomethylcysteine (SeMeCys) in hyperaccumulators (eg. Stanleya pinnata). There is no convincing explanation on SeCys2 accumulation in C. hupingshanesis based on current Se metabolism theory in higher plants, and further study will be needed. PMID:23750270

  12. Functional analysis of metals distribution in organs of the beetle Chrysolina pardalina exposed to excess of nickel by Micro-PIXE

    NASA Astrophysics Data System (ADS)

    Przyby?owicz, W. J.; Mesjasz Przyby?owicz, J.; Migula, P.; G?owacka, E.; Nakonieczny, M.; Augustyniak, M.

    2003-09-01

    Micro-PIXE mapping of elemental distribution within organs of Chrysolina pardalina beetle feeding on a nickel hyperaccumulating plant species Berkheya coddii, was used to check its ability to cope with excess of nickel and to study quantitative and qualitative relations between nickel and other elements in physiologically important structures. Data analysis was performed using a new PC based version of the GeoPIXE software (GeoPIXE II). The use of micro-PIXE, supported with analysis of electronograms demonstrated mechanism of Ni rejection from the insects' body. Concretions rich in Zn, Cu, Fe, Mn, Br are formed in Malpighian tubules and in the midgut cells. Organs important for maintaining homeostasis are protected against excess of metals. Malpighian tubules play a crucial role in Ni elimination from hemolymph, further rejected through the digestive tract and in larve also with exuvia during molting. Both used methods proved that midgut cells in adults could regenerate. Such an adaptive mechanism has not been earlier described in adult beetles.

  13. Heavy metal removal and crude bio-oil upgrade from Sedum alfredii Hance harvest using hydrothermal upgrading.

    PubMed

    Yang, Jian-guang; Tang, Chao-bo; He, Jing; Yang, Sheng-Hai; Tang, Mo-tang

    2010-07-15

    In this study, heavy metals were removed and crude bio-oil was yielded from a heavy metal hyperaccumulator harvest, Sedum alfredii Hance, through hydrothermal upgrading process. This paper reports on the optimization of process parameters for the removal of heavy metals (zinc, lead, and copper) and for the upgrading of crude bio-oil from this biomass in an autoclave. 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 >60% 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 (K(2)CO(3)) for 60 s. Under these optimized conditions, an oil phase (mostly composed of phenolic hydrocarbons and derivatives), a water phase raffinate (containing Zn(2+) (0.39 g/L), Pb(2+) (0.10 g/L), Cu(2+) (0.15 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:20409636

  14. 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 (1mm) granularity, and 22.1MPa at 370 degrees C in the presence of 10mg/L additives for 60s. Under these optimized conditions, an oil phase (mostly composed of phenolic hydrocarbons and derivatives), a water phase raffinate containing Zn(2+) (0.39g/L), Pb(2+) (0.10g/L), Cu(2+) (0.16g/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:20576570

  15. 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

  16. 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

  17. 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

  18. Response of the lichen Cladonia rei Schaer. to strong heavy metal contamination of the substrate.

    PubMed

    Osyczka, Piotr; Rola, Kaja

    2013-07-01

    The phenomenon of mass occurrence of the lichen Cladonia rei in extremely contaminated post-smelting slag dumps was studied in relation to metal accumulation capacity of this lichen. The research was aimed to evaluate the relationships between element contents in the thalli and in the corresponding substrate. The study was conducted in terms of a wide spectrum of Zn, Cd, Pb and As contents. The concentrations of these elements in the lichen thalli and substrate samples were measured. Various regression models were considered to find the best fitted one that greatly reflects the dependencies. Various Cladonia species and the hyperaccumulator Diploschistes muscorum were also included in the study for comparison purposes. Specific non-linear regression models described by a power function reflected relationships between Zn and Cd contents in C. rei thalli and in the host substrate in the most reliable way. The relationship for As was also noted, but none significant model was found. Contrarily, Pb concentrations in the thalli varied independently of the metal levels in the substrate. Nevertheless, the concentrations of all measured heavy metals in C. rei thalli are relatively low considering the frequently enormous substrate contamination. Different Cladonia species demonstrated a generally similar accumulation capacity and could be considered as weak accumulators. The restrained accumulation pattern may be one of the important attributes of C. rei which facilitates its colonisation of extremely contaminated dumps. This finding highlights ecological importance of this species as stable and resistant pioneer in such affected sites. PMID:23589242

  19. Different Heavy Metal Accumulation Strategies of Epilithic Lichens Colonising Artificial Post-Smelting Wastes.

    PubMed

    Rola, Kaja; Osyczka, Piotr; Kafel, Alina

    2016-02-01

    Lichens appear to be essential and effective colonisers of bare substrates including the extremely contaminated wastes of slag dumps. This study examines the metal accumulation capacity of epilithic lichens growing directly on the surface of artificial slag sinters. Four species representing different growth forms, i.e., crustose Candelariella aurella, Lecanora muralis, and Lecidea fuscoatra and fruticose Stereocaulon nanodes, were selected to evaluate the relationships between zinc, lead, cadmium, and nickel contents in their thalli and host substrates. Bioaccumulation factors of examined crustose lichens showed their propensity to hyperaccumulate heavy metals. Contrarily, concentrations of metals in fruticose thalli of S. nanodes were, as a rule, lower than in the corresponding substrates. This indicates that the growth form of thalli and degree of thallus adhesion to the substrate has a significant impact on metal concentrations in lichens colonising post-smelting wastes. Nonlinear regression models described by power functions show that at greater levels of Pb concentration in the substrate, the ability of C. aurella, L. muralis and L. fuscoatra to accumulate the metal experiences a relative decrease, whereas hyperbolic function describes a similar trend in relation to Ni content in S. nanodes. This phenomenon may be an important attribute of lichens that facilitates their colonisation of the surface of slag wastes. PMID:26155778

  20. 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