Figure 2.

Growth of parental and transgenic A. thaliana on organomercurials. (A–C) Growth on PMA. Seeds from the merBpe line B4 (center of each plate) germinated and grew on growth media containing no mercury (A) and 2 μM PMA (B and C). Transgenic merA9pe seeds (Left) and wild-type RLD (Right) seeds used as controls, did not germinate on PMA. Plates in A and B were photographed at 4 weeks. The plate shown in C is the same as in B, photographed 2 weeks later. (D–G) Growth on methylmercury. Seeds from the B4 line (Center) also grew on substrates with no mercury (D), 0.5 μM CH₃HgCl (E), and 2 μM CH₃HgCl (F and G). Plates were photographed after 5 (D–F) and 8 (G) weeks incubation. Transgenic merA9pe (Left) and RLD (Right) seeds do not grow on these concentrations of CH₃HgCl. (H–I) Growth comparisons among independent lines on PMA. Seeds from four independently isolated transgenic lines (B1, B4, B5, B8) representing a range of merBpe expression levels germinated and plants grew on no mercury (H) and 1 μM PMA (I), while the wild-type RLD seeds and plants grew only on the control plate (H). Plates in H and I were photographed at 3 weeks post-germination.