DICENTRIC CHROMATID BRIDGES AND POLLEN STERILITY IN CLEOME GYNANDRA

The present investigation revealed that the haploid chromosome number of Cleome gynandra (Linn) is n=9 and 4n=36. It is essentially a tetraploid. Meiotic chromosome behaviour in pollen mother cells (PMCs) in this tetraploid at Anaphase I and II were highly irregular. The percentage of chromatid bridges observed during the course of investigation in this tetraploid species was found to be 40.35. In the present investigation the tetraploid species investigated showed 47.60% morphologically fertile pollens, and 52.40% morphologically sterile pollens. It appears that the high frequency of chromatid bridges formed (40.35%) and 52.40% pollen deformity seems to indicate that chromatid bridges were not beneficial to the ecological aptitude of the taxon with regards to its sexual reproduction as deformed pollens often are nonviable. From the results of the present investigation, it was clear that structural alterations in the chromosomes due to largely frequent bridge formation appeared to be part of a common factor contributing to the sterility of pollen grains in Cleome gynandra.