The effect of salt stress on growth stage progression of in vitro- and soil-grown Arabidopsis and E. salsugineum. A, Seedlings were transferred by mesh at stage 0.5 to fresh control in vitro medium and medium supplemented with the indicated NaCl concentrations. B, Stage 1.0 seedlings were transferred to soil from in vitro plates and subjected to the indicated salt treatments. Salt treatments commenced at stage 1.02 with 50% of the final salt concentration. One hundred percent of each salt level was applied at stage 1.04. Developmental stages are according to Boyes et al. (2001). Boxes represent the time elapsed between the successive growth stages. Junctions between boxes of different shading indicate the occurrence of a growth stage. Data are mean of three independent experiments. Each experiment contained either three or more replicate plates with approximately 15 seedlings per plate (in vitro) or approximately 10 replicate plants (soil).