Karyotype Analysis with Differential Banding in Crinum pratense and Crinum defixum

Abstract

Although Crinum pratense and C. defixum have similar karyomorphology i.e. 2n=22 chromosomes, diffuse type of interphase nuclei and continuous type of prophase chromosomes when stained with orcein, yet a major variation, such as two CMA-positive bands in C. pratense and one in C. defixum at mataphase were found. The CMA-positive bands in both the species were found in in-terphase and as well as prophase. The GC-rich repetitive sequences seemed to keep their domain in-tact throughout the cell cycle. During counter staining with DAPI, the CMA-positive portions showed DAPI-negative bands. Reversible banding indicated that the amount of GC-rich bases was more abundant in the former species. Moreover, DAPI-positive bands appeared at the centromeric regions of 18 out of 22 chromosomes in C. pratense which were totally absent in C. defixum. It showed the AT-rich nature of C. pratense chromosome complements. Two species had different isozyme activity. Activities of esterase and acid phosphatase were higher in C. defixum. Thus the two species showed distinct variations in their fluorescent karyotypes and activities of isozymes. These features support their different species rank.