Cytological Studies on the Responses of Onion Root-Tip Cells to Water-Soluble Tobacco Smoke Extracts from Various Experimental Cigarettes

Abstract

Young roots from onion bulbs were treated with different concentrations of water-soluble extracts of tobacco smoke condensate from 4 experimental cigarettes (IA1, IA2, IA3, and IA4). The cigarettes have varied in amounts of tar, nicotine and total phenols produced (Table 2). From the treated roots, meristematic cells were examined for various cytological parameters. TSC from all cigarettes induced mitotic irregularities. These abnormalities consisted of breakage of chromosomes during metaphase or anaphase, stickiness at metaphase and bridging at anaphase. The mitotic irregularities increased with increasing concentrations of TSC. There were no significant differences in potency of TSC from four experimental cigarettes in inducing mitotic abnormalities. In addition to the mitotic irregularities, TSC from different cigarettes inhibited cell wall formation which resulted in binucleate cells. Thus, the present studies clearly show that TSC from various cigarettes, yielding different amounts of tar and nicotine, have no differential cytological effects on onion root-tip cells.