Zinc and Cadmium Uptake by Hyperaccumulator Thlaspi caerulescens Grown in Nutrient Solution

Abstract

Phytoremediation of heavy‐metal‐contaminated soils can be an inexpensive means to remove hazardous metals from soil. Two metallophytes, Thlaspi caerulescents (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 µM Zn + 0.063 µM Cd to 10000 µM Zn + 200 µM Cd. Thlaspi caerulescens showed much greater tolerance to Zn/Cd treatments than the other species, with toxicity stress only apparent at the 10000 µM Zn/200 µM Cd treatment. In this treatment, shoot concentrations of Zn and Cd were 33600 and 1140 mg kg−1, respectively. Thlaspi caerulescens was also more effective at translocating both Zn and Cd from solution to shoots. Zinc concentration in shoots of T. caerulescens was higher than the other species at all Zn/Cd treatments. Cadmium concentration in shoots of T. caerulescens were significantly higher than in bladder campion only at the 316 µM Zn/6.32 µM Cd treatment. This genotype of T. caerulescens may not hyperaccumulate Cd. However, extreme Zn and Cd uptake and tolerance is evident in T. caerulescens, with >25000 mg Zn kg−1 and 1000 mg Cd kg−1 before yield is reduced. Results suggest that T. caerulescens may be a candidate for the phytoremediation of Zncontaminated soils.

Metal concentration and metal mass of metallicolous, non metallicolous and serpentine Noccaea caerulescens populations, cultivated in different growth media

“…The results of Zn concentrations in hydroponics are close to those of Shen et al (2000; Zn concentration in solution of 500μM), Zhao et al (1998;1000μM) or Brown et al (1995;3600μM Zn in solution) after approximately 1 month of culture when using the metallicolous PR population. Brown et al (1995) showed values of Zn concentration of 26,000 mg/kg and Zn mass of 35 mg/plant with 3600 μM Zn after 30 days of growth.…”

“…Most experiments were performed with nutrient solutions (e.g. Brown et al 1995;Assunção et al 2003a) or with non-contaminated soils supplemented with metal salts (e.g. Meerts et al 2003).…”

Vegetable species for phytoextraction of boron, copper, lead, manganese and zinc from contaminated soil

“…According to that a hyperaccumulator should concentrated more than 10,000 mg kg -1 of Zn or Mn, 1,000 mg kg -1 of Ni, Pb or Cu and more than 100 mg kg -1 of Cd (DW) (Brown et al, 1995). The mustard and amaranth exhibited the highest concentration of metals in shoots, while kenaf was the lowest for all the metals considered and the highest of boron (Table 2).…”

Toxidez de zinco no crescimento e nutrição de Eucalyptus maculata e Eucalyptus urophylla em solução nutritiva

“…Resposta quadrática foi obtida na concentração de Ca nas raízes de E. urophylla, observando-se decréscimo nas doses intermediárias de Zn, enquanto em E. maculata não foi afetada significativamente pelas doses de Zn em solução. Brown et al (1995) também observaram redução na concentração de Ca nas raízes de Thlaspi caerulescens em dose de 3.160 µM de Zn. A concentração de Mg nos tecidos também foi influenciada pelo aumento das doses de Zn em solução.…”