<p>Some of the developing apertures in <i>lsq6</i> tetrads are not aligned with any apertures in sister microspores. (A-D) Tetrads from the wild-type (A, C) and <i>lsq6</i> (B, D) plants exhibit similar tetrahedral morphology. (A, B) Single optical sections. Membrane structures are stained with CellMask Deep Red (magenta) and callose walls are stained with calcofluor white (blue). Scale bars = 5 μm. (C, D) 3-D reconstructions from confocal z-stacks of the tetrads shown in (A) and (B). Each of the four microspores in a tetrad is labeled with a number. (E-F’) 3-D reconstruction and surface rendering from confocal z-stacks of a wild-type (<i>INP1pr</i>:<i>INP1-YFP</i>) (E) and a <i>lsq6</i> (F, F’) tetrad of microspores allows visualizing apertures developing on microspore surfaces (magenta). Microspore surfaces were transiently labeled with DAPI (green) and rendered with IMARIS (E) or Nikon Elements (F, F’). Developing apertures (indicated by arrowheads) are visible due to underlying INP1-YFP fluorescence (E, magenta) or with the help of the membrane stain CellMask Deep Red (F, F’, magenta). (F) A view of a <i>lsq6</i> tetrad that shows alignment between apertures on sister microspores (arrowheads). (F’) A different view of the same tetrad that shows an aperture (arrow) not aligned with any apertures in a sister microspore. See also <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1006060#pgen.1006060.s007" target="_blank">S1</a> and <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1006060#pgen.1006060.s008" target="_blank">S2</a> Movies.</p
