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Physiological evidence for a high‐affinity cadmium transporter highly expressed in a Thlaspi caerulescens ecotype
Author(s) -
Lombi E.,
Zhao F. J.,
McGrath S. P.,
Young S. D.,
Sacchi G. A.
Publication year - 2001
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 - 10.1046/j.1469-8137.2001.00003.x
Subject(s) - hyperaccumulator , ecotype , cadmium , xylem , phytoremediation , botany , chromosomal translocation , transporter , biology , chemistry , environmental chemistry , biochemistry , heavy metals , gene , organic chemistry
• Uptake kinetics and translocation characteristics of cadmium and zinc are presented for two contrasting ecotypes of the Cd/Zn hyperaccumulator Thlaspi caerulescens , Ganges (southern France) and Prayon (Belgium). • Experiments using radioactive isotopes were designed to investigate the physiology of Cd and Zn uptake, and a pressure‐chamber system was employed to collect xylem sap. • In contrast to similar Zn uptake and translocation, measurements of concentration‐dependent influx of Cd revealed marked differences between ecotypes. Ganges alone showed a clear saturable component in the low Cd concentration range; maximum influx V max for Cd was fivefold higher in Ganges; and there was a fivefold difference in the Cd concentration in xylem sap. Addition of Zn to the uptake solution at equimolar concentration to Cd did not decrease Cd uptake by Ganges, but caused a 35% decrease in Prayon. • There is strong physiological evidence for a high‐affinity, highly expressed Cd transporter in the root cell plasma membranes of the Ganges ecotype of T. caerulescens . This raises evolutionary questions about specific transporters for non‐essential metals. The results also show the considerable scope for selecting hyperaccumulator ecotypes to achieve higher phytoextraction efficiencies.