Fig. 7From: Hydroponic cultivation conditions allowing the reproducible investigation of poplar root suberization and water transportOsmotic stress experimental series. a–f Pictures visualizing the gradual decline of poplar plant vitality with decreasing osmotic potentials. Osmotic potentials of the nutrient solution below − 0.8 MPa resulted in irreversible plant damage (e, f). g Root lengths after 5 weeks of hydroponic cultivation including a final week of osmotic stress. The dotted reference line for 4-week-old roots is based on Fig. 3c. Roots ≤ 5 cm of length were excluded from the analysis, as they have emerged significantly later and were not entirely exposed to the osmotic stress conditions. Differential letters indicate significant differences (Kruskal–Wallis ANOVA) at p ≤ 0.05. n = 34–81 individual roots from 1 biological replicate per stress treatmentBack to article page