Characterization of chromosome complement in Tridactylina kirilowii (Turcz. ex DC.) Schultz-Bip. by aceto-orcein, CMA, DAPI and FISH

Abstract

Tridactylina kirilowii (Turcz. ex DC.) Schultz-Bip., the Anthemideae Cass., Asteraceae displayed the chromosome number of 2n=18 for the first time. The chromosomes of the species at mitotic metaphase were characterized by chromosome size, centromeric position, distribution of the G-C and A-T heterochromatin-rich regions by aceto-orcein, CMA, DAPI, and FISH. The smallest chromosome at mitotic metaphase was approximately 4.1±0.5 μm, while the largest chromosome was 6.9±0.7 μm. The total length of the chromosome complement at mitotic metaphase was 97.5±7.9 μm. The chromosome complement at mitotic metaphase showed 16 median-centromeric chromosomes and two submedian-centromeric chromosomes. The CMA stained the whole chromosomes, and showed four brighter bands on the terminal positions of four chromosomes and were convenient with the four sat-chromosomes. DAPI stained the whole set of the chromosomes at mitotic metaphase, while CMA-DAPI positively, brightly stained some heterochromatin regions in the chromosomes at mitotic prometaphase Applying FISH using the digoxigenin labeled pTa71 probe of 45S rDNA to sets of the mitotic chromosomes showed four red colored signals that were located at the terminal region displayed after hybridization of the probe with four median chromosomes at mitotic metaphase.