Cytotoxic Effects of Chemical Mutagens in Root Tip Cells of Allium cepa L.

Abstract

One of the excellent plant models for identifying various chromosomal abnormalities is Allium cepa L. In order to create genetic diversity, chemical mutagens such as; Ethyl methanesulfonate (EMS), Ethidium bromide (EtBr) and Sodium azide (SA) were used to mutagenize the plant's germplasm. The present study was carried out to determine how these chemicals affected the Mitotic Index (MI) and phase, chromosomal abnormalities, and frequency of micronuclei in the root tip cells of A. cepa Mutagens, in general, alter the genetic structure of the organisms, which is reflected in changes to a variety of features. Further, the genome's sensitivity was discovered through cytological examination when the three mutagens were used. The chromosomal entity was impacted by a variety of clastogenic and nonclastogenic alterations, as well as mitodepressive effects. The increase in dose/concentration of all the mutagens was shown to increase the frequency of both mitotic aberrant cells and mitotic chromosomal abnormalities in the treated root tip cells. Both chemical mutagens were shown to be less effective than EtBr at disrupting mitotic cell activity and primarily causing clastogenic chromosomal abnormalities. Numerous chromosomal aberrations, including stickiness and clumping of chromosomes with varying frequencies, fragments, laggards, bridges, precocious movements, micronuclei formation at telophases, and multipolar anaphases and telophases, were reported to be present in the mitotic aberrant cells. Anaphases, telophases, disorganised metaphases, desynchronized metaphases, and persisting nucleoli during anaphase were all noted.