Effects of water soluble oncostatic fraction from Rheum officinale Baill. rhizomes on Allium cepa root meristem. I. The mitotic activity

The effects of the oncostatic extracts from Rheum officinale rhizomes on the activity of meristematic cells from Allium cepa roots were investigated. A statistically significant decrease of the IM value was noted as well as of the total number of mitoses during incubation. The disturbances in the course of mitosis and cytokinesis are described and discussed. The kind of disturbances during postincubation points to damage of the S and G2 phases of the interphase nuclei. Cytochemical and autoradiographic studies demonstrated a diminished intensity of staining of DNA and RNA and inhibition of DNA synthesis during incubation, this leading in tum to a lower intensity of protein staining in postincubation. Disturbances in mitosis and cytokinesis after treatment wth 2,6-dihydroxyantraquinone, supposed to be the antimitotically active compound of the extract, are the same as those produced by the total water soluble fraction