Article révisé par les pairs
Résumé : Background and aimsAdequate cultural cycles for phytoextraction with Noccaea caerulescens have never been investigated, whereas they directly influence biomass production. The aim of this study was to investigate the effects of the season of establishment, the seeding strategy (sowing vs transplantation) and the length of the growing season on biomass production and metal accumulation of N. caerulescens.MethodsA field trial was conducted on an urban wasteland contaminated with trace metals. Two populations with contrasted natural life cycles, one Cd-accumulating metallicolous (Ganges, GAN) and one non-metallicolous from Luxemburg (LUX), were compared in 6 cultural cycles.ResultsDirect sowing in the fall yielded satisfying metal uptake (260 g Cd ha−1 with GAN and 25 kg Zn ha−1 with LUX), though lower than those obtained with transplantation (320 g Cd ha−1 with GAN and 45 kg Zn ha−1 with LUX) due to less biomass production (1.6 vs 3.2 t ha−1). Extending the growing period from 6 to 12 months was mostly beneficial for biennial LUX plants (with 3 times higher Zn uptake), than for annual GAN plants (with 1.5 times higher Cd uptake).ConclusionsThe natural variation in life cycles – annual or biennial – of N. caerulescens should be taken into account when selecting cultivars for phytoextraction.