Effects of the overexpression of TaeIF5A1 on abiotic stress tolerance in transgenic poplar plants. A–B. The seedlings of WT and transgenic lines grown on 1/2MS medium supplemented with 0 and 0.6 % NaCl for 20 d, the phenotypes of plantlets were photographed and the height was measured. C. Comparison of the relative rates of growth in height and basal diameter in WT and transgenic poplar lines. The plantlets with similar height from each line and control plants (sample size of 10 plantlets) growing in soil were treated with 0.8% NaCl solution for 30 d then watered normally, the height and basal diameter were measured after 90 d of treatment. RGH or RDG were calculated as: (final value - baseline value) / baseline value × 100 and presented as a percentage. D–E. The plantlets of WT and transgenic plants (2 and 3) with similar size were grown on 1/2MS medium supplied with 300 μM of CuSO4, CdCl2, 1 mM of ZnCl2, and 200 mM of sorbitol. After 16 d of stress, the phenotypes of plantlets were photographed and the height was measured. The error bars represent standard deviations of the mean measurements. * means significant difference (P < 0.05) between transgenic lines and WT plants. WT, wild type poplar plants; 1–10, ten lines of transgenic poplar plants.