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

Afton SE, Catron B, Caruso JA - J. Exp. Bot. (2009)

Bottom Line: The chromatographic results depict that selenium and arsenic species were sequestered in the roots and generally conserved upon translocation to the leaves.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Cincinnati/Agilent Technologies Metallomics Center of the Americas, University of Cincinnati, Cincinnati, OH 45221-0172, USA.

ABSTRACT
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.

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78Se and 75As IPRP-ICPMS chromatograms of the root extracts from C. comosum after varying supplementation combinations; the profiles shown are highly similar to several other chromatograms collected from identically treated plant material.
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fig3: 78Se and 75As IPRP-ICPMS chromatograms of the root extracts from C. comosum after varying supplementation combinations; the profiles shown are highly similar to several other chromatograms collected from identically treated plant material.

Mentions: To characterize further the selenium and arsenic-containing compounds in C. comosum root extracts after varying supplementation combinations, IPRP-ICPMS was incorporated and the resulting chromatograms are shown in Fig. 3. The calculated column recovery was 87±3% (75As) and 55±1% (78Se) for SeIV and AsIII supplemented plants (n=3) indicating a minimal loss of arsenic from analyte adsorption to the stationary phase; however, the selenium loss may be caused by non-eluting selenium macromolecular compounds. Although the amount of selenium and arsenic in the soil was not quantified, the control plants provide insight into the low molecular weight species metabolized after long-term exposure to selenium and arsenic concentrations naturally found in commercial soil over the 9 month cultivation period. Only inorganic selenium and arsenic species were observed in C. comosum control roots. In addition, plants supplemented with selenium or arsenic singly showed a decrease in abundance for arsenic or selenium species, respectively, which supports the proposed antagonistic effect between the two.


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

Afton SE, Catron B, Caruso JA - J. Exp. Bot. (2009)

78Se and 75As IPRP-ICPMS chromatograms of the root extracts from C. comosum after varying supplementation combinations; the profiles shown are highly similar to several other chromatograms collected from identically treated plant material.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2657536&req=5

fig3: 78Se and 75As IPRP-ICPMS chromatograms of the root extracts from C. comosum after varying supplementation combinations; the profiles shown are highly similar to several other chromatograms collected from identically treated plant material.
Mentions: To characterize further the selenium and arsenic-containing compounds in C. comosum root extracts after varying supplementation combinations, IPRP-ICPMS was incorporated and the resulting chromatograms are shown in Fig. 3. The calculated column recovery was 87±3% (75As) and 55±1% (78Se) for SeIV and AsIII supplemented plants (n=3) indicating a minimal loss of arsenic from analyte adsorption to the stationary phase; however, the selenium loss may be caused by non-eluting selenium macromolecular compounds. Although the amount of selenium and arsenic in the soil was not quantified, the control plants provide insight into the low molecular weight species metabolized after long-term exposure to selenium and arsenic concentrations naturally found in commercial soil over the 9 month cultivation period. Only inorganic selenium and arsenic species were observed in C. comosum control roots. In addition, plants supplemented with selenium or arsenic singly showed a decrease in abundance for arsenic or selenium species, respectively, which supports the proposed antagonistic effect between the two.

Bottom Line: The chromatographic results depict that selenium and arsenic species were sequestered in the roots and generally conserved upon translocation to the leaves.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Cincinnati/Agilent Technologies Metallomics Center of the Americas, University of Cincinnati, Cincinnati, OH 45221-0172, USA.

ABSTRACT
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.

Show MeSH
Related in: MedlinePlus