Zinc tolerance and accumulation in metallicolous and nonmetallicolous populations of Arabidopsis halleri (Brassicaceae)

Abstract

Zinc tolerance was investigated in five populations of Arabidopsis halleri (syn. : Cardaminopsis halleri) raised from seeds collected from contaminated and uncontaminated sites. Tolerance was measured by determining the concentration which inhibited root growth (EC "!! ). A. halleri populations from contaminated and uncontaminated sites were found to be Zn-tolerant compared with the Zn-nontolerant species Arabidopsis thaliana and A. lyrata subsp. petraea. At very high Zn concentrations, populations of A. halleri from uncontaminated sites were slightly less Zn-tolerant than those from contaminated sites. These observations support the hypothesis that in A. halleri, Zn tolerance is largely a constitutive property. One population from an uncontaminated site and one population from a contaminated site were studied for Zn uptake. Zinc content was measured in shoots and roots using a colorimetric test under laboratory conditions. The results showed that whatever their origin, individuals from both populations are Zn accumulators compared with the nonaccumulator species A. thaliana. Moreover, the population from the uncontaminated area accumulated Zn in its shoots and roots more quickly than the population from the contaminated site. These results suggest that, in A. halleri, Zn accumulation to very high concentration is a constitutive property.

Cd AND Zn TOLERANCE AND ACCUMULATION BYSEDUM JINIANUMIN EAST CHINA

“…They have been found mainly in colonized areas with high Zn, Cd, and Pb present in soil due to historical mining activities and the subsequent contamination of the topsoil with mine spoil rich in heavy metals, especially in parts of Europe and Australia Baker et al, 2000). The present study indicates that S. jinianum can tolerate Zn concentrations up to 1600 µmol L −1 in nutrient solution without a reduction in dry matter yield, which is similar to published results for T. caerulencens (Brown et al, 1995bb), A. halleri (Bert et al, 2000;Zhao et al, 2000), and S. alfredii Hance (Yang et al, 2006). The Zn concentrations in the leaves, stems, and roots increased linearly with increasing Zn concentration in the nutrient solution from 1.0 to 9600 µmol L −1 , whereas Zn accumulation patterns in shoots of T. caerulencens and A. halleri increased linearly with increasing Zn levels up to 1000 µmol L −1 (Brown et al, 1995aa;Zhao et al, 2000), and in S. alfredii Hance increased linearly with Zn concentrations up to 500 µmol L −1 (Yang et al, 2006).…”

Evolution of nickel hyperaccumulation and serpentine adaptation in the Alyssum serpyllifolium species complex

“…However, across the geographic range of these species, there is a significant positive correlation between the degree of tolerance and substrate metal concentration, indicative of local adaptation to the natural habitat (Roosens et al, 2003;Pauwels et al, 2005). The relationship between metal tolerance and hyperaccumulation is rather less clear, and although the highest shoot metal concentrations observed in the field are found in populations growing on metalliferous soils, there is some evidence that the level of metal hyperaccumulation shown by these populations may be inversely related to their degree of metal tolerance (Bert et al, 2000;Roosens et al, 2003).…”

“…Two of the most intensively studied species of hyperaccumulator plants, Arabidopsis halleri (L.) O'Kane & Al-Shehbaz (formerly Cardaminopsis halleri (L.) Hayek) and Noccaea caerulescens (J Presl and C Presl) FK Mey. (formerly Thlaspi caerulescens J Presl and C Presl), display a basal, constitutive level of zinc tolerance and hyperaccumulation in both metallicolous and non-metallicolous populations (Meerts and Van Isacker, 1997;Bert et al, 2000Bert et al, , 2002Escarré et al, 2000;Frérot et al, 2003;Pauwels et al, 2006;Meyer et al, 2010). However, across the geographic range of these species, there is a significant positive correlation between the degree of tolerance and substrate metal concentration, indicative of local adaptation to the natural habitat (Roosens et al, 2003;Pauwels et al, 2005).…”

“…However, only 15 described species are known to display zinc hyperaccumulation (Meerts and Van Isacker, 1997;Bert et al, 2000;Krämer, 2010), and nickel hyperaccumulation warrants further research as part of attempts to understand the evolutionary basis of plant adaptation to serpentine (Brady et al, 2005;Kazakou et al, 2008;Turner et al, 2010). The present paper thus focusses on evolution of nickel hyperaccumulation in the genus Alyssum (Brassicaceae) that contains 51 known hyperaccumulator taxa out of ∼ 190 species, making this the largest number of hyperaccumulating species found within a single genus (Brooks, 1998;Burge and Barker, 2010).…”

Zinc tolerance and hyperaccumulation are genetically independent characters

“…Lloyd-Thomas 1995) and this variation can be heritable (Pollard & Baker 1996). Arabidopsis halleri ( Cardaminopsis halleri) is a hyperaccumulator of zinc which is found exclusively on metal-contaminated sites in western Europe, though in eastern Europe it is found on both contaminated and uncontaminated sites (Fabiszewski 1986;Bert et al 2000). It is closely related to and interfertile with Arabidopsis petraea ( Cardaminopsis petraea Arabis petraea) which is both non-tolerant to zinc and a non-accumulator.…”