Quantification of the percentage of stem cells in different mitotic phases and the percentage of defective mitotic figures in 72hR anterior blastemas of xbp1/atf6 RNAi and controls in starved conditions after double immunostaining with anti-tyrosine-tubulin and anti-H3P (****P < 0.0001, ***P < 0.001, *P < 0.05, n.s. indicates not significant using two-sided Chi-square test); n ≥ 5 planarians. Representative images are shown. Arrows indicate abnormal organization or number of spindle poles. j8 displays asymmetrical distribution of chromosome content. 