A new method to detect cadmium uptake in protoplasts

Abstract

The mechanism for cadmium (Cd2+) uptake into the cytosol of protoplasts from 5- to 7-day-old wheat seedlings (Triticum aestivum L. cv. Kadett) was investigated by a new method, using fluorescence microscopy and the heavy metal-specific fluorescent dye, 5-nitrobenzothiazole coumarin, BTC-5N. Cadmium fluorescence gradually increased in the cytosol of shoot and root protoplasts upon repeated additions of CdCl2 to the external medium, reflecting an uptake of Cd2+. The uptake was inhibited by calcium and potassium chloride, as well as by Verapamil and tetraethylammonium (TEA), inhibitors of calcium and potassium channels, respectively. Calcium competitively inhibited the cadmium uptake. The metabolic inhibitors vanadate and dinitrophenol partly inhibited the uptake, suggesting it was dependent on membrane potential. The results indicate that cadmium is taken up by channels permeable to both calcium and potassium. The total uptake of cadmium into the protoplasts was also detected by unidirectional flux analyses using Cd-109(2+), and showed approximately the same maximal concentration of Cd2+ as the fluorescence measurements. By combining the two methods it is possible to detect both uptake into the cytosol and into the vacuole

Keywords

Cadmium uptake; fluorescence microscopy; protoplasts; mechanism; Triticum aestivum

Published in

Planta
2004, volume: 219, number: 3, pages: 526-532
Publisher: SPRINGER

SLU Authors

• Lindberg, Sylvia

  • Department of Plant Biology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Agricultural Science
Food Science

Publication identifier

• DOI: https://doi.org/10.1007/s00425-004-1256-z

Permanent link to this page (URI)

https://res.slu.se/id/publ/4386