Abstract
Karyotypes of 3 wild Corchorus spp. of Tiliaceae, namely C. tridens, C. fascicularis and C. pseudo-capsularis, were investigated after differential staining with orcein, CMA and DAPI. In addition, the activities of 3 isozymes, esterase, acid phosphatase and peroxidase in these 3 species were compared. These 3 spp. were found to possess 2n=14 metacentric chromosomes. The CMA and DAPI bands were found in either the terminal or interstitial region of the respective chromosomes of 3 species. This indicated a tendency for the accumulation of GC- and AT-rich repeats at terminal or interstitial region of the chromosomes. The number and distribution of CMA- and DAPI-bands were unique for each species. A comparison of CMA- and DAPI-banding pattern indicated the presence of paracentric inversion in the concerned areas of the respective chromosomes. Different types of heteromorphicity regarding CMA- and DAPI-banding revealed the probable occurrence of deletion and tandem duplication. In acid phosphatase, 2 common bands were found in C. fascicularis and C. pseudo-capsularis. A dark, thick peroxidase band was found in C. fascicularis whereas a light, thick band occurred in C. pseudo-capsularis. These light and dark thick bands could be used as markers for these 2 spp. Moreover, a big upper esterase band makes C. tridens unique.
