Abstract: The chromosomal ultrastructure and the chromosomal substances of ribonucleoprotein (RNP) and argyrophilic proteins of Prorocentrum sp. were studied using the techniques of conventional staining, RNP preferential staining and Ag-staining. Most part of the RNP in the chromosomes of Prorocentrum sp. was in the form of fibril distributed around the DNP throughout the chromosone. The RNP in the periphery of the chromosomes was found to form a closed membrane-like structure. Many kinds of the argyrophilic proteins were distributed regularly in the chromosome of Prorocentrum sp., but varied greatly in quantity from cell to cell. The amount of argyrophilic proteins in the chromosomes of some cells was much more than that in the nucleoplasm, but in other cells the amount of argyrophilic proteins was less than that in the nucleoplasm. The results indicated that in addition to argyrophilic proteins, RNA might play a role in the maintenance of the chromosome structure at a high level.

Key words: Prorocentrum sp., Chromosome, Ultrastructure, Ribonucleoprotein, Argyrophilic Protein