Loss of SDG2 impairs the primary root stem cell niche maintenance. A

<p>and <b>B</b>, Comparison of primary root apical meristem sizes between wild-type <i>Col</i> and the mutant <i>sdg2-3</i>, respectively. DIC images were taken on the roots of 6-day-old seedlings. Arrowheads indicate positions of the transition from meristem to elongation zone. Bar = 100µm. <b>C</b> and <b>D</b>, Comparison of <i>QC25:GUS</i> expression and root cap cell layer organization between <i>Col</i> and <i>sdg2-3</i>, respectively. DIC images were taken on GUS- and Lugol-stained root tips of 6-day-old seedlings. Arrowheads indicate the columella initial cell layer. Bar = 20 µm. <b>E</b> and <b>F</b>, Comparison of cell layer organization of root apical meristem between <i>Col</i> and <i>sdg2-3</i>, respectively. Confocal images were taken on PI-stained roots of 6-day-old seedlings. Bar = 50 µm. The close-up regions are shown by color indication of different cell types: QC cell in blue, columella root cap and columella initial cells in rose, lateral root cap cells in sky-blue, epidermal cells and epidermis/lateral root cap initials in red, cortex cells in green, endodermal cells in yellow, cortex/endodermis initials in purple, stele cells and stele initials in gray. <b>G</b> and <b>H</b>, Comparison of cell layer organizations of root apical meristem between <i>Col</i> and <i>sdg2-3</i>, respectively. Confocal images were taken on PI-stained roots of 14-day-old seedlings. Bar = 50 µm. The close-up regions are shown with colorations as described in <b>E</b> and <b>F</b>.