Phenotypes of NT poplar and PeHKT1;1 transgenic lines under salt stress conditions. Six-week-old non-transgenic (NT) and four transgenic poplar lines (T1, T2, T3, and T4) were treated with 0.2, 0.3, 0.4, and 0.5% w/v NaCl for two weeks. (A) Phenotypic observation of NT and transgenic poplar lines. The unstressed NT poplar (NT-0) were the positive control and NaCl-treated NT poplar (NT-1) was the negative control. All treatments had three biological replicates. Scale bar represents 1 cm. (B) The statistical analyses of plant height and adventitious root number. Data were analyzed using one-way ANOVA followed by Duncan’s test. Error bars with letters represent significant differences (p < 0.05, Duncan’s test).