Figure 5.

Mercury accumulation in the pEpi plants. (a–c) Col-0 (wild-type), p35S (merC-SYP121 over-expressing line) and the pEpi lines were grown on the control agar medium for 10 d and then transferred to the medium containing 10 µM HgCl₂ for 1 d. Mercury concentrations in shoots (a) and roots (b) were separately quantified by CV-AAS. Mercury translocation ratios (c) were calculated by dividing Hg concentrations of shoots by those of roots. Data represent means with SD (n = 4). Asterisks indicate significant differences from the values of Col-0 (*P < 0.05, Student’s two-tailed t test). (d–f) Col-0, p35S and the pEpi lines were grown on the agar medium containing 0.2 µM HgCl₂ for 12 d. Mercury concentrations in shoots (d) and roots (e) and translocation ratios (f) were obtained. Data represent means with SD (n = 4–6). Asterisks indicate significant differences from the values of Col-0 (*P < 0.05, **P < 0.01, Student’s two-tailed t test).