Nickel effect on root-meristem cell division in Plantago lanceolata (Plantaginaceae) seedlings

The toxic effect of nickel (Ni) on cell division on root-meristem cells in seedlings of Plantago lanceolata L. was studied and compared. Seed material was collected from serpentine and non-serpentine populations of the species distributed in the Rhodope Mountains, Bulgaria. The root-tip meristem cells of germinated seeds were treated with different solutions of 0.01, 0.025, 0.05, 0.1mM Ni as NiSO4 6H(2)O with distilled water for 24 h and 48 h respectively. The mitotic index decreased when Ni concentrations and exposure time increased in both type of samples. Significant differences in the mitotic indexes were found between the controls and the roots treated with Ni. The mitotic index was higher in root-meristem cells of serpentine seedlings. C-mitosis, anaphase bridges, chromosome stickiness, laggards and extrusion of nuclear material into the cytoplasm were observed in the root-tip cells treated with Ni. The percentage of aberrations generally increased in a concentration-and time-dependent manner. The percentage of the extruded nuclei was higher in cells treated with 0.05 and 0.1mM Ni. It can be concluded that P. lanceolata seedlings on serpentine can tolerate higher Ni concentrations than can non-serpentine seedlings.