The morphology and size of phragmoplast, a novel plant cell-specific apparatus in cytokinesis, are strictly regulated. In this issue, Wan et al. (pp. 622–634) showed in KATANIN P80 over-expression rice plants that the phragmoplast is lengthened while the distance between two daughter nuclei is shortened. Consequently, root growth in those lines is retarded, suggesting an important role of KATANIN in cytokinesis.