Does the origin of cuttings influence yield and phytoextraction potential of willow in a contaminated soil?

Plant survival and growth are essential parameters in monitoring the effectiveness of phytoremediation protocols for brownfields decontamination. The ability of different willow cultivars to survive and adapt to contamination in polluted soils can vary according to the nature and concentration of the contaminants. The objectives of this study were to identify which cultivars had the highest yields, and to determine whether the origin of the cuttings influences survival, growth and phytoextraction potential of willow cultivars when grown on polluted soil. Survival, growth and phytoextraction of trace elements (Cd, Cr, Cu, Ni, Pb, Zn) were compared for ten willow cultivars planted in a highly organic-contaminated industrial environment versus in uncontaminated soil. Variations in cultivar response according to cutting origin (contaminated site or not) were also analysed for each site. Results show that, Salix nigra '5005' was very productive in an extremely contaminated environment. Salix eriocephala 'S25' also performed exceptionally well, as it produced large root biomass (nearly twice that the other cultivars). The highest concentration of cadmium was found in S. x dasyclados 'SV1'; cultivars S. purpurea x S. miyabeana 'Millbrook' and S. eriocephala 'S25' exhibited the highest concentrations of chromium. Cultivar 'S25' was also the most effective at concentrating copper, and S. miyabeana 'SX67' was the most efficient at phytoextracting zinc. The origin of the cuttings did not have a significant influence on survival, growth or phytoextraction, except for 'Millbrook' : individuals originating from the contaminated environment produced significantly more aboveground biomass when grown in a contaminated environment, compared to individuals who had never been in contact with contaminants. These results could help build more effective phytoremediation protocols for highly contaminated environments by identifying willow cultivars and cutting selection techniques appropriate for specific environments.