[Coincidence of Feulgen-achromasia, in situ hybridization and silver banding in four nucleolus organizers of Vicia sativa (author's transl)].

The results of three cytological techniques have been used to clear up the chromosomal locus and function of NOs in a commercial cultivar of Vicia sativa (2n=12) from Rumania. Karyotypic investigations after Feulgen-staining and arrangement of chromosomes in order of decreasing length of the long arm define chromosome I and chromosome III as SAT-chromosomes. The loci of the Feulgen-negative secondary constrictions coincide with those of the grain clusters after in situ rRNA/DNA hybridization and those of silver precipitation after ammoniacal silver staining. The median position of the weak secondary constriction in the long arm of chromosome I coincides with the position of the small grain cluster after in situ hybridization and the small silver dot after silver staining. The submedian position of the strong secondary constriction in the long arm of chromosome III coincides with the position of the big grain cluster and the big silver dot.