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Title: Uptake, sequestration and tolerance of cadmium at cellular levels in the hyperaccumulator plant species Sedum alfredii

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [2];  [3];  [1];  [2];  [1]
  1. MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou 310058, China
  2. Department of Plant Sciences, University of California, Davis, CA 95616, USA
  3. National Research Center for Geoanalysis, Beijing 100037, China
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1430371
Grant/Contract Number:
AC02-06CH11357
Resource Type:
Journal Article: Published Article
Journal Name:
Journal of Experimental Botany
Additional Journal Information:
Journal Volume: 68; Journal Issue: 9; Related Information: CHORUS Timestamp: 2018-03-29 00:36:33; Journal ID: ISSN 0022-0957
Publisher:
Oxford University Press
Country of Publication:
United Kingdom
Language:
English

Citation Formats

Tian, Shengke, Xie, Ruohan, Wang, Haixin, Hu, Yan, Hou, Dandi, Liao, Xingcheng, Brown, Patrick H., Yang, Hongxia, Lin, Xianyong, Labavitch, John M., and Lu, Lingli. Uptake, sequestration and tolerance of cadmium at cellular levels in the hyperaccumulator plant species Sedum alfredii. United Kingdom: N. p., 2017. Web. doi:10.1093/jxb/erx112.
Tian, Shengke, Xie, Ruohan, Wang, Haixin, Hu, Yan, Hou, Dandi, Liao, Xingcheng, Brown, Patrick H., Yang, Hongxia, Lin, Xianyong, Labavitch, John M., & Lu, Lingli. Uptake, sequestration and tolerance of cadmium at cellular levels in the hyperaccumulator plant species Sedum alfredii. United Kingdom. doi:10.1093/jxb/erx112.
Tian, Shengke, Xie, Ruohan, Wang, Haixin, Hu, Yan, Hou, Dandi, Liao, Xingcheng, Brown, Patrick H., Yang, Hongxia, Lin, Xianyong, Labavitch, John M., and Lu, Lingli. Wed . "Uptake, sequestration and tolerance of cadmium at cellular levels in the hyperaccumulator plant species Sedum alfredii". United Kingdom. doi:10.1093/jxb/erx112.
@article{osti_1430371,
title = {Uptake, sequestration and tolerance of cadmium at cellular levels in the hyperaccumulator plant species Sedum alfredii},
author = {Tian, Shengke and Xie, Ruohan and Wang, Haixin and Hu, Yan and Hou, Dandi and Liao, Xingcheng and Brown, Patrick H. and Yang, Hongxia and Lin, Xianyong and Labavitch, John M. and Lu, Lingli},
abstractNote = {},
doi = {10.1093/jxb/erx112},
journal = {Journal of Experimental Botany},
number = 9,
volume = 68,
place = {United Kingdom},
year = {Wed Apr 12 00:00:00 EDT 2017},
month = {Wed Apr 12 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1093/jxb/erx112

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  • Sedum alfredii is one of a few plant species known to hyperaccumulate cadmium (Cd). Uptake, localization, and tolerance of Cd at cellular levels in shoots were compared in hyperaccumulating (HE) and non-hyperaccumulating (NHE) ecotypes of Sedum alfredii. X-ray fluorescence images of Cd in stems and leaves showed only a slight Cd signal restricted within vascular bundles in the NHEs, while enhanced localization of Cd, with significant tissue- and age-dependent variations, was detected in HEs. In contrast to the vascular-enriched Cd in young stems, parenchyma cells in leaf mesophyll, stem pith and cortex tissues served as terminal storage sites for Cdmore » sequestration in HEs. Kinetics of Cd transport into individual leaf protoplasts of the two ecotypes showed little difference in Cd accumulation. However, far more efficient storage of Cd in vacuoles was apparent in HEs. Subsequent analysis of cell viability and hydrogen peroxide levels suggested that HE protoplasts exhibited higher resistance to Cd than those of NHE protoplasts. These results suggest that efficient sequestration into vacuoles, as opposed to rapid transport into parenchyma cells, is a pivotal process in Cd accumulation and homeostasis in shoots of HE S. alfredii. This is in addition to its efficient root-to-shoot translocation of Cd.« less
  • 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 mainlymore » 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.« less
  • Sedum alfredii (Crassulaceae), a species native to China, has been characterized as a Zn/Cd cohyperaccumulator and Pb accumulator though the mechanisms of metal tolerance and accumulation are largely unknown. Here, the spatial distribution and speciation of Pb in tissues of the accumulator plant was investigated using synchrotron-based X-ray microfluorescence and powder Extended X-ray absorption fine structure (EXAFS) spectroscopy. Lead was predominantly restricted to the vascular bundles of both leaf and stem of the accumulator. Micro-XRF analysis revealed that Pb distributed predominantly within the areas of vascular bundles, and a positive correlation between the distribution patterns of S and Pb wasmore » observed. The dominant chemical form of Pb (>60%) in tissues of both accumulating (AE) and nonaccumulating ecotype (NAE) S. alfredii was similar to prepared Pb-cell wall compounds. However, the percentage of the Pb-cell wall complex is lower in the stem and leaf of AE, and a small amount of Pb appeared to be associated with SH-compounds. These results suggested a very low mobility of Pb out of vascular bundles, and that the metal is largely retained in the cell walls during transportation in plants of S. alfredii.« less