Thlaspi caerulescens on nonmetalliferous soil in Luxembourg: ecological niche and genetic variation in mineral element composition

Abstract

Summary• Forty-seven populations of Thlaspi caerulescens in Luxembourg were characterised for population size, soil mineral element composition and other habitat characteristics. Foliar concentrations of eight elements were assessed in 15 populations in the field and in eight populations cultivated in zinc (Zn)-cadmium (Cd)-nickel (Ni)-enriched soil.• T. caerulescens favoured stony soil developed on steep, south-facing Emsian shale outcrops. All soil samples were nonmetalliferous. Soil pH ranged from 4.2 to 6.9. Field-growing plants had very high concentrations of heavy metals in the leaves (Zn, 3000 -13 000 mg kg − 1 ; Cd, 11-44 mg kg ). Positive soil-plant correlations existed for Zn and Mn.• In cultivation, significant genetic variation was found for biomass and six of eight mineral elements. For Cd and Zn, variation range among 48 half-sib families was two-fold (Cd, 183-334 mg kg − 1 ; Zn, 8030 -16 295 mg kg − 1 ). Most of the variation occurred among populations, consistent with the selfing mating system of those populations. There was a tight Zn-Cd genetic correlation ( r = +0.83, P < 0.0001).• The significance of the results to the conservation of T. caerulescens in Luxembourg is briefly discussed.

Phytoremediation of urban soils contaminated with trace metals using Noccaea caerulescens: comparing non-metallicolous populations to the metallicolous ‘Ganges’ in field trials

“…caerulescens (Brassicaceae, formerly Thlaspi caerulescens) is one of the most promising candidate species for Cd and Zn phytoextraction (Koopmans et al 2008;Maxted et al 2007;McGrath et al 2006;Zhao et al 2003). Three ecotypes of N. caerulescens have been described: metallicolous plants grow in soils enriched in Cd-Zn-Pb (calamine, CAL) and in serpentine sites (mostly enriched in Ni), whereas non-metallicolous (NMET) grow in uncontaminated soils (Escarré et al 2000;Meerts and van Isacker 1997;Molitor et al 2005;Reeves et al 2001). CAL and NMET ecotypes have different metal-related traits.…”

“…Experimental design and plant cultivation N. caerulescens seeds came from three populations: two NMET from the Grand Duchy of Luxemburg, Wilwerwiltz and Goebelsmühle (hereafter WIL and GOE) (Molitor et al 2005), and one metallicolous Ganges (GAN, or BAvinières^) from St-Laurent-le-Minier, France (Escarré et al 2000). Seedlings of N. caerulescens were grown in greenhouse for 2.5 months before transplanting in the field.…”

“…It appears that life history traits and the adaptation to biotic pressure are as much relevant as metal-related traits (e.g., accumulation), and that all should be considered when trying to select for ideotypes for phytoextraction. There is a clear interest in selecting, for example, for higher individual biomass among and within populations judged most suitable for phytoextraction, given the large inter-and intra-pop variation in biomass production (Meerts and van Isacker 1997;Molitor et al 2005). Furthermore, considering the relative genetic proximity between MET and NMET populations from South of France within one divergent genetic unit (Jiménez-Ambriz et al 2007;Gonneau et al 2017), it can be expected that the latter accumulate more Cd than NMET from Luxemburg, even if it is still less than GAN population (Escarré et al 2000).…”

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

“…In 9 NMET soils in Switzerland (<120 mg/kg of Zn in soil), Zn leaf concentrations values averaged 4857 mg/kg (Basic et al 2006), and in 15 NMET populations from Luxembourg (soil=8.6 mg/kg Zn) mean Zn leaf values were 7300 mg/kg (Molitor et al 2005). Banásová et al (2008) found mean Zn concentrations of 13650 mg/kg and of 10729 mg/kg in MET and NMET populations, respectively, in central Slovakia.…”

“…In each population, seeds from 20-30 flowering plants were collected. To analyse the extractable Zn, Cd, Pb and Ni concentrations of soil, bulk samples were air-dried, ground and the <2 mm fractions were separated from coarse rock (Frérot et al 2006) Total Zn 126126±17620 mg/kg; total Cd 899±200 n=3 (Escarré et al 2011) b (Dechamps et al 2008a,b;Molitor et al 2005) c Total Zn concentration (Reeves et al 2001) d Total Ni concentration: 146 to 2500 mg/kg (Chardot et al 2007) e Total Ni concentration:784-1984 mg/kg (Reeves et al 2001) fragments by sieving. All chemical analyses were performed on the <2 mm soil fractions.…”