International Journal of Medicinal Plants and Alternative Medicine Vol. 2(2), pp. 021-026, August 2014 ISSN 2327-560X ©2013 Academe Research Journals

Full Length Research Paper

Comparative effects of colchicine, 8-hydroxyquinoline and paradichlorobenzene on arm ratio of mitotic chromosomes of Allium cepa L.

Ekong N. J.¹*, Akpan G. A.² and Udo I. J.²

¹Department of Biological Sciences, Faculty of Pure and Applied Sciences, Federal University Wukari,

Taraba State, Nigeria.

²Department of Botany and Ecological Studies, University of Uyo, Uyo, Akwa Ibom State, Nigeria.

*Corresponding author. E-mail: joesplendid@yahoo.com. Tel: +234(0)7062726072.

Accepted 5 July, 2014

Abstract

Studies were carried out to assess the comparative effects of aqueous solution of colchicine (0.5%), 0.004M 8-hydroxyquinoline and saturated solution of paradichlorobenzene on the arm ratios of mitotic chromosomes using Allium cepa L. as the test organism. Samples were collected separately and fixed in acetic alcohol (1:3 v/v) for 24 h at room temperature. Chromosome characteristics in A. cepa were determined. Karyotypic analysis of the onion root tips showed a preponderance of median chromosomes. Analysis of variance for chromosome arm ratios showed that there are no significant differences (p<0.05) among the treatments in arm ratio. This research work therefore suggests that though the three pre-treatment chemicals are all effective in inhibiting the mitotic spindle and arresting the chromosomes at metaphase, each chemical elicits a differential contraction of the chromosomes.

Key words: Arm ratio, mitotic chromosomes, idiograms, haploid complement, centromeric position.