Fig. 2 (a) Mercury concentrations (in µmol·g-1 FW) in roots and shoots, and (n = 4)(b) chlorophyll fluorescence parameters in wild type (Col-0),cad2-1 , pad2-1 , rax1-1 and cad1-3 Arabidopsis thaliana treated with 0 and 3 µM Hg for 72 h: PSII efficiency (ΦPSII), photochemical quenching (qP ) and non-photochemical quenching (NPQ) (n = 8). Different letters denote significant differences atp <0.05