Salicylic Acid Triggers Adaptation Cadmium Cytogenetic Toxicity in Roots of Nigella saliva L

CADMIUM (Cd) is a toxic heavy-metal pollutant in the environment, it is a nonessential element, which strongly inhibits plant growth and development, and causes plant death even at very low concentrations. Root tip cells of Nigella saliva were separately treated with different concentrations (5, 10, 25 and 5Oppm) of cadmium for 3, 6, 12 and 24h and the results were recorded. The results showed that all concentrations of cadmium reduced the mitotic index and caused a disturbance in the frequencies of mitotic phases. The treatment with 50ppm of metal for 24h was the most effective in reducing the mitotic activity and inducing the high es t percentage of mitotic abnormalities. The different types of abnormalities were irregulatries, bridges, sickness at different phases, disturbed chromosomes or bi nucleated cells, forward and lagging chromosomes. Also, in this study three concentrations of SA (0.01, 0.1 and 0.2mM) for 6 and 12h were used to recover the cytotoxicity of the cadmium treatment (50ppm for 3 and 24h). This Post treatment with SA resulted in increasing MI and significant reduction of chromosomal abnormalities. These results illustrate the ameliorating effect of SA under stress conditions and reveal that SA is effective in alleviating the toxic effects of heavy metals at all applied concentrations.