Staining plant cells with silver. II. Chromosome cores

Abstract

A new technique called salt-nylon silver staining has been used to stain cores in the chromosomes of Lilium longiflorum. Cores are visible in both mitotic and meiotic chromosomes. In C-metaphase chromosomes, a thin core is coiled to form a thick core in each chromatid. In early prophase I of meiosis, silver-stained axial cores and synaptonemal complexes show no indication of coiling before their disappearance in early diplotene. In diakinesis, pairs of thin cores reappear in large major coils. These cores can be seen to cross over between homologous chromosomes. By metaphase I, thin cores coil to form thick cores, which themselves spiral in major coils. The most striking appearance of the cores occurs during anaphase I, when homologous chromosomes separate and sister chromatids swing apart to display thick cores in major coils. During meiosis II cores are in minor coils embedded in elongate chromosomes that show relic major coiling. These observations indicate that plant chromosomes have silver-stainable cores that are comparable with cores that have been reported in the chromosomes of mammals and grasshoppers.Key words: chromosome cores, silver staining, mitosis, meiosis, plants.