title: Placement of active ribosomal cistrons in the nucleolus organizing chromosomes of Allium cepa L.
mesh_terms: D002466:Cell Nucleolus; D002871:Chromosome Banding; D002875:Chromosomes / Q000032:analysis* / Q000648:ultrastructure; D005796:Genes; D007621:Karyotyping; D009697:Nucleolus Organizer Region / Q000032:analysis*; D010944:Plants / Q000235:genetics* / Q000648:ultrastructure; D012335:RNA, Ribosomal / Q000235:genetics*
chemical_list: D012335:RNA, Ribosomal