Chromosomal Aberrations Induced By Colchicine Treatment In Allium Cepa Var Aggregatum Root Meristems: A Study Of Mitotic Inhibition And Metaphase Arrest

Colchicine is an alkaloid that features a carbotricyclic structure, consisting of a 5,6,7,9-tetrahydrobenzo[a]heptalene core with four methoxy groups at positions 1, 2, 3, and 10, an oxo group at position 9, and an acetamido group at position 7. It is derived from plants of the Colchicum genus. Colchicine acts as a microtubule-destabilizing agent and is a plant metabolite. This study investigates the effects of colchicine on the mitotic cycle in root apical meristems of Allium cepa var aggregatum (onion). Onion bulbs were treated with different concentrations of colchicine (0.5%, 1.0%, and 1.5%) to analyze its impact on mitosis inhibition and chromosomal aberrations. The colchicine-treated root meristem cells showed a range of mitotic abnormalities, including laggards, stickiness, vagrant chromosomes, binucleated cells, and nuclear lesions. The study also observed a dose-dependent increase in aberrations, with higher colchicine concentrations leading to more pronounced effects. Chromosome preparations were analyzed under a light microscope, revealing disruptions in metaphase alignment and anaphase movement. Mitotic Index and frequency of abberant cells was also calculated. The results highlight colchicine’s ability to inhibit normal cell division and form dumbbell shaped nucleus, which was observed for the first time, providing insight into its potential applications in cytogenetic studies.