| Antimony（Sb）is listed as a highly hazardous toxic substance and carcinogenic substance by the European Union,and belongs to the first category of pollutants in China.China is rich in Sb ore resources.Guizhou is one of the main distribution areas of Sb ore.with the mining of Sb ore,the soil around the mining area is seriously polluted by Sb.This not only threatens the safe production of agricultural products,but also brings great hidden dangers to human health.Therefore,it is very necessary to treat and repair antimony contaminated soil.Sodium silicate and calcium chloride can provide essential nutrients for rice growth,promote rice growth and alleviate the toxicity of heavy metals to rice.However,there are few reports on the effects of sodium silicate and calcium chloride on rice growth and Sb accumulation under Sb stress.Therefore,on the basis of field sampling,analysis and testing of rice soil around Sb mining area,this study selected different concentrations of sodium silicate and calcium chloride to study the effects of sodium silicate and calcium chloride on rice germination and seedling growth under Sb stress through seed germination experiment and pot experiment.The main conclusions are as follows:（1）The Sb content of paddy soil around the typical Sb mining area in Dushan County,Guizhou ranges from 5.91 mg/kg to 32.56 mg/kg,and some paddy soil Sb pollution belongs to light pollution and heavy pollution.There was a significant negative correlation between urease activity,phosphatase activity and Sb content in paddy soil.（2）Sb had a significant stress effect on rice germination and seedling growth.The addition of 5mg/L～30mg/L Sb could inhibit the germination rate,germination potential,vigor index and root dry weight of rice;The plant height,fresh weight of roots and buds and dry weight of roots and buds of rice seedlings also decreased by 2.60%～15.27%,25.83%～43.65%,8.33%～34.66%,11.77%～51.52% and 13.21%～27.21% respectively.（3）Applying different concentrations of sodium silicate and calcium chloride alone can improve the germination potential,germination rate,vigor index,root length,bud length,root dry weight and bud dry weight of rice.Under the stress of 5mg/L～30mg/L Sb,the addition of 1mmol/L sodium silicate and 5mmol/L calcium chloride could significantly increase the germination potential,germination rate,vigor index and dry weight of roots and buds.With the increase of Sb concentration,the absorption of Sb by rice sprouting roots and buds gradually increased,and the transport coefficient and enrichment coefficient were inversely proportional to Sb concentration.Exogenous addition of different concentrations of sodium silicate and calcium chloride can effectively reduce the absorption and accumulation of Sb in rice sprouting roots and buds.（4）When different concentrations of sodium silicate and calcium chloride were applied alone,the plant height,fresh weight and dry weight of roots and buds of rice seedlings increased in varying degrees.Under the stress of 5 mg/L～30 mg/L Sb,different concentrations of sodium silicate could promote the increase of plant height,fresh weight and dry weight of roots and buds of rice seedlings,and inhibit the toxicity of Sb to rice seedlings.The effect of 1 mmol/L sodium silicate was the most significant.Different concentrations of sodium silicate could reduce the absorption and accumulation of Sb in roots and buds of young rice seedlings,and the effect was the best under the action of 4mmol/L sodium silicate.The absorption and accumulation of Sb by roots and buds of young rice seedlings showed a concentration effect on the concentration of Sb,and the enrichment coefficient was less than 1.The enrichment coefficient of Sb by rice was lower than that of the control treatment when sodium silicate and calcium chloride were applied.（5）Under the treatment of sodium silicate and calcium chloride alone,the catalase activity,urease activity,sucrase activity and phosphatase activity of rice rhizosphere soil increased.Under the stress of5 mg/L～30 mg/L Sb,the catalase activity of rice rhizosphere soil increased by 1.2%～7.6%,the sucrase activity increased by 3.93%～140%,and the urease activity decreased by 7.32%～25.92%.Under the stress of 5mg/L～30 mg/L Sb,the application of different concentrations of sodium silicate and calcium chloride increased the activity of soil urease and decreased the content of Sb in rice rhizosphere soil. |
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