The effects of different concentrations of nickel sulfate on root growth and nucleoli in root tip cells ofAllium cepawere studied. The concentrations of nickel sulfate (NiSO4#xB7; 7H2O) used were in the range of 10#x2212;7-10#x2212;1M. The results showed that nickel sulfate has a stimulatory effect on root growth at lower concentrations, and an inhibitory effect at higher concentrations. Nickel has toxic effects on nucleoli at higher concentrations. Phenomena we observed were irregularly shaped nucleoli, weaker silver staining reaction at the periphery of the nucleolus, and extrusion of nucleolar material from nuclei into the cytoplasm after treatment with higher concentrations of Ni.
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