Zinc and cadmium uptake by hyperaccumulator Thlaspi caerulescens grown in nutrient solution (original) (raw)

Phytoremediation of heavy-metal-contaminated soils can be an inexpensive means to remove hazardous metals from soil. Two metallophytes, Thlaspi caerulescens (J. & C. Presl, a Zn and Cd hyperaccumulator) from Prayon, Belgium, and a Zn-tolerant ecotype of bladder campion [Silene vulgaris (Moench.) Garcke L.] from Palmerton, PA, were compared with tomato [Lycopersicon lycopersicum (L.) Karsten, metal intolerant] in nutrient solution to characterize Zn and Cd uptake and tolerance. Zinc and Cd were added to solutions at a 50:1 molar ratio to simulate concentrations often found on contaminated sites. Seven treatment concentrations were used, ranging (in half-log increments) from 3.16 \aM Zn + 0.063 uM Cd to 10000 uM Zn + 200 uMCd. Thlaspi caerulescens showed much greater tolerance to Zn/Cd treatments than the other species, with toxicity stress only apparent at the 10000 uM Zn/200 uM Cd treatment. In this treatment, shoot concentrations of Zn and Cd were 33600 and 1140 nig kg~', respectively.