Spindle Positioning, Meiotic Nonreduction, and Polyploidy in Plants
Figure 1
Formation of parallel spindles during meiosis II in atps1 gives unreduced spores.
In atps1 formation of meiosis II, spindles in a plane parallel to that during meiosis I results in each half of the cell getting one of the two sister chromatids. Cytokinesis occurs only at the end of meiosis II, and the planes of division overlap, resulting in a dyad of diploid spores.