Comaparative Effects of Three Heavy Metals on Seed Germination and Mitosis of Pearl Millet

Abstract

The problem of pollution in our natural resource base has become a major issue in the present world. All organisms are affected by this problem, but the stationary life of plants makes them more prone to damage by a variety of pollutants. Among various pollutants of air, water and soil, heavy metals are significant contributors to intoxication of plants by pollutants. They are present in majority of industrial effluents, agricultural chemicals and even domestic wastes. The plants growing in areas with high level of contamination have developed mechanisms to tolerate the toxicity. One of the mechanisms is to convert the toxic elements into less toxic salts and store them in various tissues. But even this process causes various damages to the plant. The present investigation demonstrates the effects of 3 heavy metals (Pb, Hg and Cd) on germination and early mitotic divisions of pearl millet (Pennisetum glaucum (L.) R.Br.). All the three metals were able to elicit a response in form of mitodepression and chromosomal aberrations. The study explores the reasons for the observed clastogeny and mitotic disruption. It also points out towards the reduction in survival as well as abnormal phenotype of the plants if grown in a polluted environment. The study is important since it uses Pearl Millet as the material for bioassay of heavy metals. This plant is considered very hardy and tolerant to various stresses like drought, temperature and salinity. However, heavy metals were able to induce significant abnormalities in its chromosomes, which is a clear cut indicator of their massive toxic potentials.