Fig. 4.

Undefined type of meiotic division in a microspore-derived haploid (n = 21, ABR) from a triticale hybrid: a the column of meiocytes containing the final products of meiotic division: a mixture of monads (marked with M), dyads (marked with D), tetrads (marked with T), and a few cell nuclei that did not undergo meiotic division (FCD) (marked with arrows), scale bar 40 μm; b noticeable differences in pollen grain size, scale bar 20 μm; c and d the column of meiocytes in stages similar to prophase I and anaphase I, where meiocytes seem to form a residual karyokinetic spindle (RKS) (marked with an asterisk) which makes normal separation of sister chromatids difficult, and potentially impossible. This type of meiosis exhibits many features found in FDR. It is possible that this division is extremely delayed, or cytokinesis is accelerated; however, in many cases, there are signs of attempted cell division in an unusual plane, often across the accumulated chromosomes on the metaphase plate, or at unusual angles. The arrows mark an example of this unusual type of division (AMD). Scale bar 40 μm