1994 Volume 59 Issue 1 Pages 35-42
Six cytotypes of the Scilla scilloides complex with genome constitutions of AA, BB, AB, ABB, ABBB and AABB were investigated on chromosomal location of rRNA genes by in situ hybridization. The AA, BB and AB plants had two heavy signals indicating location of rRNA genes at secondary constriction of all nucleolar chromosomes (a2 in the genome A and b1 in the genome B). In the ABB, ABBB and AABB plants the b1 chromosomes had heavy signals at secondary constriction and the a2 chromosomes had small signals on their short arms. The AABB plants collected in Okinawa had heavy signals at both a, and b, chromosomes. The heavy signals partially diffused around the nucleoli and small signals condensed in the nucleoplasm. These results suggest that the absence of secondary constriction of the a2 chromosomes in the AABB plant might be caused by deletion of most of rRNA genes. Chromosomes of the genome A were detected by genomic in situ hybridization using a probe of total DNA of Korean AA plant and this result suggests that the genomes A and B are differentiated from each other at DNA level as well as cytogenetical level.