Uptake and acute toxicity of cerium in the lichen Xanthoria parietina

• The lichen Xanthoria parietina was negatively affected by treatment with cerium.
• Total and intracellular Ce content increased with increasing Ce treatment.
• Ce decreased viability and photosynthetic performance and altered the ultrastructure.

Environmental cerium (Ce) levels are likely to increase in the near future and monitoring of its biological effects will therefore be necessary. The aim of this study was to test if treatment of the lichen Xanthoria parietina with Ce-containing solutions (0.1 mM, 1 mM, 10 mM and 100 mM) causes Ce bioaccumulation (both extra- and intra-cellularly) as well as physiological (sample viability, membrane lipids peroxidation, photosynthetic performance, water-soluble proteins content) and ultrastructural alterations. The results showed that treatment with Ce solutions induces Ce bioaccumulation, both extra-cellularly and intra-cellularly, which in turn causes an acute toxicity, evident as decreased sample viability, marked decrease in the photosynthetic performance and important changes in the ultrastructure.