Stem and leaf sequestration of zinc at the cellular level in the hyperaccumulator Sedum alfredii.
* Sedum alfredii is a fast-growing, high-biomass zinc (Zn) hyperaccumulator native to China. Here, the characteristics of in vivo Zn distribution in stems and leaves of the hyperaccumulating (HE) and nonhyperaccumulating ecotypes (NHE) of S. alfredii were investigated by synchrotron radiation X-ray fluorescence (SRXRF) analysis, together with a Zn probe. * Preferential Zn accumulation in leaf and stem epidermis was observed in both ecotypes, but to a much greater extent for HE. Epidermal Zn increased largely in leaves and stems of HE as exposure time was prolonged, while Zn saturation occurred relatively early in HE leaf mesophyll cells and stem vascular bundles. A second peak of Zn enrichment in stem and leaf vascular systems was shown in both ecotypes. However, the proportion of Zn accumulated in stem vascular bundles relative to other tissues was much greater for HE than for NHE. * Leaf and stem distribution patterns of phosphorus (P) and sulphur (S) in the HE were very like that for Zn, while the calcium (Ca) distribution pattern was the reverse of that for Zn. No such relationship was observed in NHE. * Our study mainly suggested that epidermal layers serve as important storage sites for accumulated Zn in the S. alfredii HE.
Tian
Sheng-Ke
SK
MOE Key Laboratory of Polluted Environment Remediation and Ecological Health, Zhejiang University, Huajiachi Campus, Hangzhou 310029, China.
Lu
Ling-Li
LL
MOE Key Laboratory of Polluted Environment Remediation and Ecological Health, Zhejiang University, Huajiachi Campus, Hangzhou 310029, China.
Yang
Xiao-E
XE
MOE Key Laboratory of Polluted Environment Remediation and Ecological Health, Zhejiang University, Huajiachi Campus, Hangzhou 310029, China.
Labavitch
John M
JM
Department of Plant Sciences, University of California, Davis, CA, 95616, USA.
Huang
Yu-Ying
YY
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039, China.
Brown
Patrick
P
Department of Plant Sciences, University of California, Davis, CA, 95616, USA.
D018533:Biomass; D005453:Fluorescence; D018515:Plant Leaves / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D018547:Plant Stems / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D031963:Sedum / Q000166:cytology* / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D017356:Synchrotrons; D015032:Zinc / Q000378:metabolism* / Q000494:pharmacology
D015032:Zinc