Arsenate tolerance in Silene paradoxa does not rely on phytochelatin-dependent sequestration.
Arsenate tolerance, As accumulation and As-induced phytochelatin accumulation were compared in populations of Silene paradoxa, one from a mine site enriched in As, Cu and Zn, the other from an uncontaminated site. The mine population was significantly more arsenate-tolerant. Arsenate uptake and root-to-shoot transport were slightly but significantly higher in the non-mine plants. The difference in uptake was quantitatively insufficient to explain the difference in tolerance between the populations. As accumulation in the roots was similar in both populations, but the mine plants accumulated much less phytochelatins than the non-mine plants. The mean phytochelatin chain length, however, was higher in the mine population, possibly due to a constitutively lower cellular glutathione level. It is argued that the mine plants must possess an arsenic detoxification mechanism other than arsenate reduction and subsequent phytochelatin-based sequestration. This alternative mechanism might explain at least some part of the superior tolerance in the mine plants.
Arnetoli
Miluscia
M
Section of Plant Ecology and Physiology, Department of Plant Biology, University of Florence, via Micheli 1, 50121 Firenze, Italy. miluscia@gmail.com
Vooijs
Riet
R
ten Bookum
Wilma
W
Galardi
Francesca
F
Gonnelli
Cristina
C
Gabbrielli
Roberto
R
Schat
Henk
H
Verkleij
Jos A C
JA
D001149:Arsenates / Q000633:toxicity*; D001151:Arsenic; D003300:Copper; D004361:Drug Tolerance; D004784:Environmental Monitoring / Q000379:methods; D005978:Glutathione / Q000032:analysis / Q000378:metabolism; D007220:Industrial Waste; D008906:Mining; D054811:Phytochelatins / Q000378:metabolism*; D018517:Plant Roots / Q000737:chemistry / Q000378:metabolism; D018520:Plant Shoots / Q000737:chemistry / Q000378:metabolism; D029751:Silene / Q000378:metabolism*; D012989:Soil Pollutants / Q000633:toxicity*; D015032:Zinc
D001149:Arsenates; D007220:Industrial Waste; D012989:Soil Pollutants; D003300:Copper; D054811:Phytochelatins; D005978:Glutathione; D015032:Zinc; D001151:Arsenic; C025657:arsenic acid