Physiological and Proteomic Responses of Different Willow Clones (Salix fragilis X alba) Exposed to Dredged Sediment Contaminated by Heavy Metals

Abstract

High biomass producing species are considered as tools for remediation of contaminated soils. Willows (Salix spp.) are prominent study subjects in this regard. In this study, different willow clones (Salix fragilis x alba) were planted on heavy-metal polluted dredging sludge. A first objective was assessment of the biomass production for these clones. Using a Gupta statistic, four clones were identified as high biomass producers (HBP). For comparison, a group of four clones with lowest biomass production were selected (LBP). A second objective was to compare metal uptake as well as the physiological and proteomic responses of these two groups. All these complementary data's allow us to have a better picture of the health of the clones that would be used in phytoremediation programs. Cd, Zn, and Ni total uptake was higher in the HBPs but Pb total uptake was higher in LBPs. Our proteomic and physiological results showed that the LBPs were able to maintain cellular activity as much as the HBPs although the oxidative stress response was more pronounced in the LBPs. This could be due to the high Pb content found in this group although a combined effect of the other metals cannot be excluded.

KEY WORDS:

• 2-DiGE
• antioxidant defence
• oxygen evolution
• variable fluorescence

ACKNOWLEDGMENTS

We thank Paul-Henry Fally and Yves Libert (Direction des recherches hydrauliques (DGO2), Service Publique de Wallonie) for supplying the dredging sludge, the Unité de Génie biologique of the Centre wallon de Recherches agronomiques (Belgium) for supplying the willow plants and the Unité de Statistique, Informatique et Mathématique appliquées of Gembloux Agro-Bio Tech (Université de Liège, Belgium). We also thank BEAGx (GxABT, ULg) for elemental analysis of the soil. We acknowledge Dr. Lucien Hoffmann from the CRP Gabriel Lippmann for his careful reading of the manuscript, Johanna Ziebel for the elemental analyses, Laurent Solinhac for his continuous help and Sébastien Planchon for his support during the proteomics experiments. The authors declare no financial/commercial conflicts of interest.