Effect of Digitonin on Cellular Division Part VI

Abstract

The cytological and ultrastructural changes occurring in meristematic cells of Allium sativum root tips following treatment with digitonin have been described (Olah , 1965Underbrink and Olah 1963, 1965, 1968Olah and Hanzely 1973). These include a selective effect on the organization and function of two microtubular systems during mitosis, i.e. the mitotic and the phragmoplast spindle.In this report, we present observations on the occurrence of a unique digitonin induced tubular element in dividing root tip cells of Allium sativum. Materials and methodsThe conditions of growth, digitonin treatment, and the methods of specimen preparation for electron microscopy have been described in detail in previous papers (Olah 1965 Olah andHanzely 1973). In brief, Allium sativum root tips, treated for 15 hours with 0.25% and 0.5% purified digitonin solutions, were prefixed in 6% glutaraldehyde containing CaCl2, washed, postfixed in 1% osmium tetroxide, dehydrated in a methanol series and embedded in Epon. Thin sections were mounted on uncoated grids, counterstained with uranyl acetate and lead citrate, and examined with a Hitachi HU 125E electron microscope operated at 75 kv. ObservationsSimilar to the effect of colchicine, digitonin prevents the formation of spindle microtubules and the alignment of chromosomes at metaphase (Figs.