Fig. 4

Phenotype of PtoLAC14-KO transgenic poplar lines. a Images of 3-month-old PtoLAC14-KO lines and WT; scale bar is 10 cm. b Plant height and stem diameter in the PtoLAC14-KO and WT of 3-month-old. c Toluidine blue staining and scanning electron microscopy (SEM) images (Xy: xylem, Xf: xylem fiber cells, Xv: xylem vessel. Scale bars are 100 μm and 10 μm, respectively). d Lumen area of individual xylem vessel cell, fiber cell, and cell wall thickness. Data represent mean ± SD (n = 3 in b and n = 30 in d). Student’s t-test was performed between the transgenic lines and WT as **P < 0.01