the authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest .
in angiosperms , mitosis and cytokinesis take place in the absence of structurally defined microtubule - organizing centers and the underlying mechanisms are largely unknown . in the spindle and phragmoplast , 
 microtubule reorganization depends on microtubule - interacting factors like the -tubulin complex . 
 because of their critical functions in cell division , loss - of - function mutations in the corresponding genes are often homozygous or sporophytic lethal . 
 however , a number of mutations like gem1 , gcp2 , and nedd1 can be maintained in heterozygous mutants in arabidopsis thaliana . 
 when mutant microspores produced by a heterozygous parent undergo pollen mitosis i , they are amenable for phenotypic characterization by fluorescence microscopy . the results would allow us to pinpoint at specific functions of particular proteins in microtubule reorganization that are characteristic to specific stages of mitosis and cytokinesis . 
 conclusions made in the developing microgametophytes can be extrapolated to somatic cells regarding mechanisms that regulate nuclear migration , spindle pole formation , phragmoplast assembly , and cell division plane determination .