A drop-spreading technique to produce cytoplasm-free mitotic preparations from plants with small chromosomes

A preparation technique has been developed for plants with small chromosome s, which produces large numbers of good-quality mitotic preparations. The t echnique employs a hydrochloric acid treatment to hydrolyse the cytoplasm, facilitating the subsequent removal of cytoplasmic debris. The evaporative force of a methanol-based fixative is exploited to disperse the cytoplasm a nd to deposit the chromosomes in a single optical plane. This technique per mits detailed observations of chromosome morphology and karyotyping. The mi totic preparations are also suitable for the complex analysis associated wi th in-situ hybridization, as in studies of genome interaction in plant hybr ids.