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Cadmium sorption, influx, and efflux at the mesophyll layer of leaves from ecotypes of the Zn/Cd hyperaccumulator Thlaspi caerulescens
Author(s) -
Ebbs Stephen D.,
Zambrano M. Clemencia,
Spiller Shawna M.,
Newville Matthew
Publication year - 2009
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2008.02693.x
Subject(s) - hyperaccumulator , cadmium , ecotype , efflux , xanes , sorption , chemistry , apoplast , botany , biology , biophysics , cell wall , biochemistry , phytoremediation , environmental chemistry , heavy metals , physics , organic chemistry , adsorption , quantum mechanics , spectroscopy
Summary• Differential sorption and transport characteristics of the leaf mesophyll layer of the Prayon and Ganges ecotypes of the hyperaccumulator Thlaspi caerulescens were examined. • 109 Cd influx and efflux experiments were conducted with leaf sections, and X‐ray absorption near edge structure (XANES) data were collected from leaves as a general comparison of in vivo cadmium (Cd) coordination. • There were modest differences in cell wall sorption of Cd between ecotypes. There were obvious differences in time‐ and concentration‐dependent Cd influx, including a greater V MAX for Prayon but a lower K M for Ganges for concentration‐dependent Cd uptake and a notably greater Cd uptake by Ganges leaf sections at 1000 µ m Cd. Leaf sections of Prayon had a greater Cd efflux than Ganges. The XANES spectra from the two ecotypes suggested differences in Cd coordination. • The fundamental differences observed between the two ecotypes may reflect differential activity and/or expression of plasma membrane and tonoplast transporters. More detailed study of these transporters and the in vivo coordination of Cd are needed to determine the contribution of these processes to metal homeostasis and tolerance.