| Abstract: | An argentophilic structure is present in the metaphase chromosomes of garlic (Allium sativum). Cytochemical studies indicate that the main component of the structure is non-histone proteins (NHPs). The results of light and electron microscopic observations reveal that the chromosme NHP scaffold is a network which is composed of fibres and granules and distributed throughout the chromosomes. In the NHP network, there are many condensed regions that are connected by relatively looser regions. The distribution of the condensed regions varies in individual chromosomes. In some of the chromosomes the condensed regions are longitudinally situated in the central part of a chromatid while in others these regions appear as coillike transverse bands. At early metaphase, scaffolds of the sister chromatids of a chromosome are linked to each other in the centromeric region, meanwhile, they are connected by scafold materials along the whole length of the chromosome. At late metaphase, however, the connective scaffold materials between the two sister chromatids disappear gradually and the chromatids begin to separate from one another at their ends, but the Chromatids are linked.together in the centromeric region until anaphase. This connection seems to be related to the special structure of the NHP scaffold formed in the centromeric region. The morphological features and dynamic changes of the chromosome scaffold are discussed. |
