A Paradichlorobenzene, Saponin, Iron Mordant Sequence in the Staining of Meiotic Chromosomes of Ipomea

For the meiotic study of Ipomea spp., flower buds were stripped of the calyx and corolla and soaked in saturated aqueous paradichlorobenzene at about 28° C for 3 hr, transferred to acetic-alcohol (1:3) for 6 hr, then into 1% saponin solution and left overnight. They were mordanted in 1:3 acetic-alcohol saturated with ferric oxide for 24 hr and stained in a mixture of 1% aceto-carmine and 2% aceto-orcein with 1 N HCl in the proportion of 9:9:1. The preparations were mounted in 1% aceto-carmine for temporary use and made permanent by dehydration through the n-butanol schedule. The pollen mother cells had clear cytoplasm with deeply stained chromosomes.