Effects of chemicals on some members of Indian charophyta I

Abstract

The effects of four different chemicals (colchicine, MH, caffeine and theobromine) on four taxa belonging to Chara and Nitella have been studied cytologically. Out of four different chemicals, MH did not produce any immediate cytological effects, which however, appeared subsequently when the materials were transferred to chemical free medium subsequent to treatments. All the chemicals brought about mitotic inhibition in all the algae investigated, to some extent or the other, levels of inhibition depending upon the concentrations of the chemicals or durations of treatment in the same concentrations. Of the four chemicals, theobromine proved to be most potent mitotic inhibitor. Colchicine has induced polyploidy, even upto the level of tetraploidy in C. globularis and C. braunii. Cytokinetic inhibition was brought about rarely by colchicine in C. globularis and more frequently by caffeine and theobromine treatments resulting in binucleate cells. Pycnotic nuclei were observed in all the treatments of the chemicals but at higher concentrations. Clumping of chromosomes at metaphase was produced by all the chemicals to varying degrees. Incomplete c-mitotic effect was observed only in N. flagellijormis with caffeine treatment. All the four chemicals proved to be cytotoxic to the algae under investigation, depending upon the concentration and duration of treatment. Theobromine even at 0.05% to 0.01% concentrations appeared to be cytotoxic. Algal materials appeared to be more resistant to the chemicals under study, as compared with higher plants. © 1990, Taylor and Francis Group, LLC.