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Silicon (Si) can enhance the resistance of plants to many abiotic stresses. To explore whether Si ameliorates Fe2+ toxicity,a hydroponic experiment was performed to investigate whether and how Si detoxifies Fe2+ toxicity in rice (Oryza sativa L.) roots.Results indicated that rice cultivar Tianyou 998 (TY998) showed greater sensitivity to Fe2+ toxicity than rice cultivar Peizataifeng (PZTF).Treatment with 0.1 mmol L-1 Fe2+ inhibited TY998 root elongation and root biomass significantly.Reddish iron plaque was formed on root surface of both cultivars.TY998 had a higher amount of iron plaque than PZTF.Addition of Si to the solution of Fe treatment decreased the amount of iron plaque on root surface by 17.6% to 37.1% and iron uptake in rice roots by 37.0% to 40.3%,and subsequently restored root elongation triggered by Fe2+ toxicity by 13.5% in the TY998.Compared with Fe treatment,the addition of 1 mmol L-1 Si to the solution of Fe treatment increased xylem sap flow by 19.3% to 24.8% and root-shoot Fe transportation by 45.0% to 78.6%.Furthermore,Si addition to the solution of Fe treatment induced root cell wall to thicken.These results suggested that Si could detoxify Fe2+ toxicity and Si-mediated amelioration of Fe2+ toxicity in rice roots was associated with less iron plaque on root surface and more Fe transportation from roots to shoots.