Karyotype analysis of Lilium longiflorum and Lilium rubellum by chromosomebanding and fluorescence in situ hybridisation

Detailed karyotypes of Lilium longiflorum and L. rubellum were constructed on the basis of chromosome arm lengths, C-banding, AgNO3 staining, and PI-D API banding, together with fluorescence in situ hybridisation (FISH) with t he 5S and 45S rDNA sequences as probes. The C-banding patterns that were ob tained with the standard BSG technique revealed only few minor bands on het erologous positions of the L. longiflorum and L. rubellum chromosomes. FISH of the 5S and 45S rDNA probes on L. longiflorum metaphase complements show ed overlapping signals at proximal positions of the short arms of chromosom es 4 and 7, a single 5S rDNA signal on the secondary constriction of chromo some 3, and one 45S rDNA signal adjacent to the 5S rDNA signal on the subdi stal part of the long arm of chromosome 3. In L. rubellum, we observed co-l ocalisation of the 5S and 45S rDNA sequences on the short arm of chromosome s 2 and 4 and on the long arms of chromosomes 2 and 3, and two adjacent ban ds on chromosome 12. Silver staining (Ag-NOR) of the nucleoli and NORs in L . longiflorum and L. rubellum yielded a highly variable number of signals i n interphase nuclei and only a few faint silver deposits on the NORs of mit otic metaphase chromosomes. In preparations stained with PI and DAPI, we ob served both red- and blue-fluorescing bands at different positions on the L . longiflorum and L. rubellum chromosomes. The red-fluorescing or so-called reverse PI-DAPI bands always coincided with rDNA sites, whereas the blue-f luorescing DAPI bands corresponded to C-bands. Based on these techniques, w e could identify most of chromosomes of the L. longiflorum and L. rubellum karyotypes.