Compartmentation of Zinc in Roots and Leaves of the Zinc Hyperaccumulator <i>Thlaspi caerulescens</i> J &amp; C Presl

Vázquez, M.D.; Poschenrieder, Charlotte; Barceló, Juan Antonio; Baker, A. J. M.; Hatton, Paul V.; Cope, G. H.

doi:10.1111/j.1438-8677.1994.tb00792.x

Cited by 162 publications

(130 citation statements)

References 19 publications

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“…Preferential accumulation of Zn in the leaf epidermis has previously been observed in the Zn hyperaccumulator Thlaspi caerulescens (Küpper et al, 1999;Vázquez et al, 1994). Our studies demonstrated that preferential distribution of Zn and Cd was also observed in epidermal cells of stem or leaf in S. alfredii (unpublished data).…”

Section: Cellular Distribution Of H 2 O 2 In Leavessupporting

confidence: 61%

Differential generation of hydrogen peroxide upon exposure to zinc and cadmium in the hyperaccumulating plant specie (Sedum alfredii Hance)

Chao

Zhang

Tian

et al. 2008

J. Zhejiang Univ. Sci. B

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Sedum alfredii Hance has been identified as zinc (Zn) and cadmium (Cd) co-hyperaccumulator. In this paper the relationships of Zn or Cd hyperaccumulation to the generation and the role of H 2 O 2 in Sedum alfredii H. were examined. The results show that Zn and Cd contents in the shoots of Sedum alfredii H. treated with 1000 μmol/L Zn 2+ and/or 200 μmol/L Cd 2+ increased linearly within 15 d. Contents of total S, glutathione (GSH) and H 2 O 2 in shoots also increased within 15 d, and then decreased. Total S and GSH contents in shoots were higher under Cd 2+ treatment than under Zn 2+ treatment. However, reverse trends of H 2 O 2 content in shoots were obtained, in which much higher H 2 O 2 content was observed in Zn 2+ -treated shoots than in Cd 2+ -treated shoots. Similarly, the microscopic imaging of H 2 O 2 accumulation in leaves using H 2 O 2 probe technique showed that much higher H 2 O 2 accumulation was observed in the Zn 2+ -treated leaf than in the Cd 2+ -treated one. These results suggest that there are different responses in the generation of H 2 O 2 upon exposure to Zn 2+ and Cd 2+ for the hyperaccumulator Sedum alfredii H. And this is the first report that the generation of H 2 O 2 may play an important role in Zn hyperaccumulation in the leaves. Our results also imply that GSH may play an important role in the detoxification of dissociated Zn/Cd and the generation of H 2 O 2 .

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Section: Cellular Distribution Of H 2 O 2 In Leavessupporting

confidence: 61%

Differential generation of hydrogen peroxide upon exposure to zinc and cadmium in the hyperaccumulating plant specie (Sedum alfredii Hance)

Chao

Zhang

Tian

et al. 2008

J. Zhejiang Univ. Sci. B

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“…Because one of the major storage sites for Zn is the leaf vacuole (Vázquez et al, 1994), we investigated the possibility that Zn influx across the leaf cell plasma membrane was stimulated in T. caerulescens. We found that at lower Zn concentrations (10 and 100 m), there were no differences in 65 Zn uptake into leaf sections or protoplasts isolated from the two Thlaspi species.…”

Section: Discussionmentioning

confidence: 99%

“…Thlaspi caerulescens seeds were obtained from plants grown near a Zn/Cd smelter in Prayon, Belgium (Vázquez et al, 1994). Seeds were grown hydroponically in 5-L black plastic tubs as described previously (Lasat et al, 1996).…”

Section: Plant Materialsmentioning

confidence: 99%

Altered Zn Compartmentation in the Root Symplasm and Stimulated Zn Absorption into the Leaf as Mechanisms Involved in Zn Hyperaccumulation in Thlaspi caerulescens

1998

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We investigated Zn compartmentation in the root, Zn transport into the xylem, and Zn absorption into leaf cells in Thlaspi caerulescens, a Zn-hyperaccumulator species, and compared them with those of a related nonaccumulator species, Thlaspi arvense. 65 Zncompartmental analysis conducted with roots of the two species indicated that a significant fraction of symplasmic Zn was stored in the root vacuole of T. arvense, and presumably became unavailable for loading into the xylem and subsequent translocation to the shoot. In T. caerulescens, however, a smaller fraction of the absorbed Zn was stored in the root vacuole and was readily transported back into the cytoplasm. We conclude that in T. caerulescens, Zn absorbed by roots is readily available for loading into the xylem. This is supported by analysis of xylem exudate collected from detopped Thlaspi species seedlings. When seedlings of the two species were grown on either low (1 M) or high (50 M) Zn, xylem sap of T. caerulescens contained approximately 5-fold more Zn than that of T. arvense. This increase was not correlated with a stimulated production of any particular organic or amino acid. The capacity of Thlaspi species cells to absorb 65 Zn was studied in leaf sections and leaf protoplasts. At low external Zn levels (10 and 100 M), there was no difference in leaf Zn uptake between the two Thlaspi species. However, at 1 mM Zn 2؉ , 2.2-fold more Zn accumulated in leaf sections of T. caerulescens. These findings indicate that altered tonoplast Zn transport in root cells and stimulated Zn uptake in leaf cells play a role in the dramatic Zn hyperaccumulation expressed in T. caerulescens.Phytoextraction is an emerging technology that involves the use of vascular plants to remediate soils contaminated with heavy metals and/or radionuclides (Nanda Kumar et al., 1995). This approach is based on the ability of higher plants to absorb contaminants from the soil and translocate them to their shoots. The identification of several metalhyperaccumulator plant species (Baker and Brooks, 1989;Baker et al., 1998) demonstrates that the genetic potential exists for successful phytoremediation of contaminated soils. One of the best-known metal hyperaccumulators is Thlaspi caerulescens J&C Presl, which has been reported to have a great potential for extraction of Zn and Cd from metalliferous soils (Reeves and

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“…These results suggest that hyperaccumulation might be a complex trait, with uptake, internal transport and tolerance being at least partly under independent genetic control. Transmembrane metal transporters may be decisively involved in uptake, xylem loading and unloading (Lasat, Baker & Kochian 1998) and vacuolar sequestration of heavy metals, particularly in the leaf epidermal cells (Vázquez et al 1994;Küpper, Zhao & McGrath 1999), trichomes (Krämer et al 1997), or stomatal guard cells (Heath, Southworth & Dallura 1997). The molecular basis of Zn uptake and transport in plants is, as yet, largely unexplored.…”

mentioning

confidence: 99%

Elevated expression of metal transporter genes in three accessions of the metal hyperaccumulator Thlaspi caerulescens

et al. 2001

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Heavy metal hyperaccumulation in plants is an intriguing and poorly understood phenomenon. Transmembrane metal transporters are assumed to play a key role in this process. We describe the cloning and isolation of three zinc transporter cDNAs from the Zn hyperaccumulator Thlaspi caerulescens. The ZTP1 gene is highly similar to the Arabidopsis ZAT gene. Of the other two, one is most probably an allele of the recently cloned ZNT1 gene from T. caerulescens (Pence et al; Proceedings of the National Academy of Science USA 97, 4956-4960, 2000). The second, called ZNT2, is a close homologue of ZNT1. All three zinc transporter genes show increased expression in T. caerulescens compared with the non-hyperaccumulator congener T. arvense, suggesting an important role in heavy metal hyperaccumulation. ZNT1 and ZNT2 are predominantly expressed in roots and ZTP1 is mainly expressed in leaves but also in roots. In T. arvense, ZNT1 and ZNT2 are exclusively expressed under conditions of Zn deficiency. Their expression in T. caerulescens is barely Zn-responsive, suggesting that Zn hyperaccumulation might rely on a decreased Zn-induced transcriptional downregulation of these genes. ZTP1 expression was higher in plants from calamine soil than in plants from serpentine or normal soil. The calamine plants were also the most Zn tolerant, suggesting that high ZTP1 expression might contribute to Zn tolerance.

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Compartmentation of Zinc in Roots and Leaves of the Zinc Hyperaccumulator Thlaspi caerulescens J & C Presl

Cited by 162 publications

References 19 publications

Differential generation of hydrogen peroxide upon exposure to zinc and cadmium in the hyperaccumulating plant specie (Sedum alfredii Hance)

Differential generation of hydrogen peroxide upon exposure to zinc and cadmium in the hyperaccumulating plant specie (Sedum alfredii Hance)

Altered Zn Compartmentation in the Root Symplasm and Stimulated Zn Absorption into the Leaf as Mechanisms Involved in Zn Hyperaccumulation in Thlaspi caerulescens

Elevated expression of metal transporter genes in three accessions of the metal hyperaccumulator Thlaspi caerulescens

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