Optimization of chromosome sectioning and karyotype analysis of Spathiphyllum floribundum

To establish the optimal approach for analyzing the root tips of Spathiphyllum floribundum‘Mojo’, we compared different sampling times and pretreatments during chromosome sectioning. The results showed that the optimal sampling time was 08:45-09:15 and the optimal pretreatment was 0.002 mol·L-1 or 0.07 mmol·L-1 of 8-hydroxyquinolin or cycloheximide, respectively for 4 h. S. floribundum is a diploid plant and its chromosome number is 2n=2x=30. “Mojo” contains a B-chromosome. The karyotype analysis revealed that S. floribundum is 2n=2x=30=20m+6m (SAT)+2sm+2sm(SAT) (B-chromosome). Furthermore, chromosome 3 and 8 are metacentric, whereas the others are facrocentric. Satellites were observed in the four pairs of chromosomes (3, 4, 6, and 9). The chromosomal length ratio was 1.73, mongolicus was 2A, and the karyotype asymmetry coefficient was 56.37%.