Cellular Sequestration of Cadmium in the Hyperaccumulator Plant Species Sedum alfredii

Journal Article · Mon Jul 23 04:00:00 EDT 2012 · Plant Physiology

DOI:https://doi.org/10.1104/pp.111.183947· OSTI ID:1046848

Tian, Shengke; Lu, Lingli; Labavitch, John M; Yang, Xiaoe; He, Zhenli; Hu, Hening; Sarangi, Ritimukta; Newville, Matt; Commisso, Joel; Brown, Patrick Hugh ^[1]

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1. UCD

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.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: NSFDOE - BASIC ENERGY SCIENCES
• OSTI ID: 1046848
• Journal Information: Plant Physiology, Journal Name: Plant Physiology Journal Issue: 4 Vol. 157
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
60 APPLIED LIFE SCIENCES
ABLATION
ABSORPTION
CADMIUM
CALCIUM
DISTRIBUTION
EPIDERMIS
FINE STRUCTURE
IN VIVO
LASERS
MALIC ACID
MASS SPECTROSCOPY
ORGANIC ACIDS
OXYGEN
PLASMA
SPECTROSCOPY
ZINC