Spatial Imaging and Speciation of Lead in the Accumulator Plant <i>Sedum alfredii</i> by Microscopically Focused Synchrotron X-ray Investigation

Tian, Shengke; Lu, Lingli; Yang, Xiaoe; Webb, Samuel M.; Du, Yonghua; Brown, Patrick H.

doi:10.1021/es903921t

Cited by 88 publications

(62 citation statements)

References 39 publications

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“…The results were in agreement with the study reported by Liang et al [31]. Tan et al performed synchrotron-based X-ray microfluorescence and extended X-ray absorption fine structure spectroscopy analysis and found that Pb was predominantly restricted to the vascular bundles of both leaf and stem of the accumulator (Sedum alfredii, Crassulaceae) [35]. The dominant chemical form of Pb (>60%) in tissues existed mostly as Pb-cell wall complex.…”

Section: Ameliorative Effects Of Si On Pb-induced Inhibition Of Banansupporting

confidence: 89%

Silicate-Mediated Alleviation of Pb Toxicity in Banana Grown in Pb-Contaminated Soil

Zheng

et al. 2011

Biol Trace Elem Res

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Silicate (Si) can enhance plant resistance or tolerance to the toxicity of heavy metals. However, it remains unclear whether Si can ameliorate lead (Pb) toxicity in banana (Musa xparadisiaca) roots. In this study, treatment with 800 mg kg(-1) Pb decreased both the shoot and root weight of banana seedlings. The amendment of 800 mg kg(-1) Si (sodium metasilicate, Na(2)SiO(3)·9H(2)O) to the Pb-contaminated soil enhanced banana biomass at two growth stages significantly. The amendment of 800 mg kg(-1) Si significantly increased soil pH and decreased exchangeable Pb, thus reducing soil Pb availability, while Si addition of 100 mg kg(-1) did not influence soil pH. Results from Pb fractionation analysis indicated that more Pb were in the form of carbonate and residual-bound fractions in the Si-amended Pb-contaminated soils. The ratio of Pb-bound carbonate to the total Pb tended to increase with increasing growth stages. Treatment with 100 mg kg(-1) Si had smaller effects on Pb forms in the Si-amended soils than that of 800 mg kg(-1) Si. Pb treatment decreased the xylem sap greatly, but the addition of Si at both levels increased xylem sap and reduced Pb concentration in xylem sap significantly in the Si-amended Pb treatments. The addition of Si increased the activities of POD, SOD, and CAT in banana roots by 14.2% to 72.1% in the Si-amended Pb treatments. The results suggested that Si-enhanced tolerance to Pb toxicity in banana seedlings was associated with Pb immobilization in the soils, the decrease of Pb transport from roots to shoots, and Si-mediated detoxification of Pb in the plants.

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Section: Ameliorative Effects Of Si On Pb-induced Inhibition Of Banansupporting

confidence: 89%

Silicate-Mediated Alleviation of Pb Toxicity in Banana Grown in Pb-Contaminated Soil

Zheng

et al. 2011

Biol Trace Elem Res

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“…Pixel brightness is displayed in RGB, with the brightest spots corresponding to the highest element fluorescence. The elemental maps of potassium (K), manganese (Mn), iron (Fe), magnesium (Mg), phosphorus (P), and sulfur (S; data not shown) were similar to those reported by Tian et al (2009Tian et al ( , 2010, and there was no significant relationship of these elements with Cd. As shown in Figures 1 and 2, the distribution patterns of Cd were very different between the two contrasting ecotypes of S. alfredii.…”

Section: Comparative Study Of CD Distribution In Stems Of Nhe and He supporting

confidence: 77%

“…Cd hyperaccumulation, defined as the accumulation and tolerance of up to 100 mg Cd g 21 in shoots by plants (Baker et al, 2000), is present only in some populations of Thlaspi caerulescens, Arabidopsis halleri, and Thlaspi praecox, all belonging to the Brassicaceae family, and Sedum alfredii (Crassulaceae; Verbruggen et al, 2009;Kramer, 2010). S. alfredii is a zinc (Zn)/ Cd cohyperaccumulator and lead (Pb) accumulator, which was also of high tolerance to copper toxicity, discovered in a Pb/Zn-rich region of China (Yang et al, 2002(Yang et al, , 2004Tian et al, 2010). The plants of the hyperaccumulating ecotype (HE) of S. alfredii collected from the Pb/Zn mined site are much more tolerant to Cd stress as compared with the nonhyperaccumulating ecotype (NHE; Supplemental Fig.…”

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confidence: 99%

Cellular Sequestration of Cadmium in the Hyperaccumulator Plant Species Sedum alfredii

et al. 2011

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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 mg g 21 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.

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“…approximately one cell diameter). Despite less than optimal preservation, cryostat sections with thicknesses ranging from 10 to 100 lm are acceptable for a range of low-and intermediate-resolution applications in animals Morgan et al 2013;Novak et al 2012) and plants (Tian et al 2010). For high resolution applications such as TEM, the well-frozen surface layer can be significantly deepened to around 200 lm in fresh tissues by hyperbaric freezing or alternatively the ice damage can be eliminated by pretreating specimens typically by mild aldehyde fixation followed by infusion with a cryo-protectant such as sucrose.…”

Section: Sample Preparation For Imaging/analysis: Common Considerationsmentioning

confidence: 99%

Analytical approaches to support current understanding of exposure, uptake and distributions of engineered nanoparticles by aquatic and terrestrial organisms

et al. 2014

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Initiatives to support the sustainable development of the nanotechnology sector have led to rapid growth in research on the environmental fate, hazards and risk of engineered nanoparticles (ENP). As the field has matured over the last 10 years, a detailed picture of the best methods to track potential forms of exposure, their uptake routes and best methods to identify and track internal fate and distributions following assimilation into organisms has begun to emerge. Here we summarise the current state of the field, focussing particularly on metal and metal oxide ENPs. Studies to date have shown that ENPs undergo a range of physical and chemical transformations in the environment to the extent that exposures to pristine well dispersed materials will occur only rarely in nature. Methods to track assimilation and internal distributions must, therefore, be capable of detecting these modified forms. The uptake mechanisms involved in ENP assimilation may include a range of trans-cellular trafficking and distribution pathways, which can be followed by passage to intracellular compartments. To trace toxicokinetics and distributions, analytical and imaging approaches are available to determine rates, states and forms. When used hierarchically, these tools can map ENP distributions to specific target organs, cell types and organelles, such as endosomes, caveolae and lysosomes and assess speciation states. The first decade of ENP ecotoxicology research, thus, points to an emerging paradigm where exposure is to transformed materials transported into tissues and cells via passive and active pathways within which they can be assimilated and therein identified using a tiered analytical and imaging approach.

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Spatial Imaging and Speciation of Lead in the Accumulator Plant Sedum alfredii by Microscopically Focused Synchrotron X-ray Investigation

Cited by 88 publications

References 39 publications

Silicate-Mediated Alleviation of Pb Toxicity in Banana Grown in Pb-Contaminated Soil

Silicate-Mediated Alleviation of Pb Toxicity in Banana Grown in Pb-Contaminated Soil

Cellular Sequestration of Cadmium in the Hyperaccumulator Plant Species Sedum alfredii

Analytical approaches to support current understanding of exposure, uptake and distributions of engineered nanoparticles by aquatic and terrestrial organisms

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