Background: In recent years, nickel (Ni) has been widely applied in industrial and agricultural production and have became a kind of environmental pollution. In this study, the effect of nickel chloride (NiCl₂) with different concentration on Arabidopsis genomic stability and DNA methylation has been demonstrated. The nucleolus variation and 18S rDNA methylation after NiCl₂ treatment have been analyzed.

Results: The results are as follows: (1) The NiCl₂ could result in heritable genomic methylation variations. The genomic DNA methylation variations have been detected by methylation-sensitive amplified polymorphism (MSAP) molecular markers, and the result showed that after NiCl₂ treatment, there was methylation variation in T₀ generation seedlings, and partial sites changes maintained in T₁ generation, which suggested that the effects of NiCl₂ on DNA methylation could be heritable in offspring. (2) NiCl₂ brought deformity and damage to nucleolar structure in Arabidopsis root tip cells, and the damage was positively correlated with the NiCl₂ concentration. 3. In the nucleolus, there was increased cytosine methylation in 18S rDNA. The plant nucleolus variation and 18S rDNA methylation maybe be used as an examination indicator for Ni pollution in soil or plant.

Conclusions: NiCl₂ application caused variation of DNA methylation of the Arabidopsis genomic and offspring's. NiCl₂ also resulted in nucleolar injury and deformity of root tip cells. The methylation rate of 18SrDNA also changed by NiCl₂ added.