| Silicon（Si）is a nutrient element required for plant growth and has a significant role in improving the resistance of rice.Silicon is widely used as a soil conditioner in agricultural production.In this experiment,we used japonica rice（code named S9006）,which is commonly used in northeast China,as potting material.Test was set four treatments(low concentration of alkaline salt at 1.50 g·kg-1,high concentration of alkaline salt at 3.00 g.kg-1,low concentration of neutral salt stress at 1.25 g·kg-1,and high concentration of neutral salt stress at 2.50 g·kg-1).And different silicon preparations（Si-50G,Si-60G,Si-TG）were applied at the tillering stage of rice.We mainly investigated,at the tasseling stage under salt stress,the effects of silicon preparations containing different functional groups on rice plant growth（plant height and biomass）,leaf physiological indicators,soil physicochemical properties,rice yield at maturity and yield constitutive factors.The results of the study provide scientific solutions for improving saline soils and reducing soil salt damage.They also provide a basis for improving the growth of rice under adversity.Meanwhile,the tests give the further theoretical support for the resource utilization of silicon preparations.The main research results are as follows:（1）Under both neutral and alkaline salt stress conditions,rice growth was inhibited.The application of silicon preparations significantly increased the biomass and plant height of rice plants at the tassel stage（P<0.05）.Under alkaline salt stress conditions,Si-60G was able to increase biomass by 9.4%-10.8%and Si-TG was able to increase plant height by 10.4%-12.5%.Under neutral salt stress conditions,Si-50G increased biomass by 6.9%-9.7%and plant height by8.9%-13.0%.（2）Under neutral and alkaline salt stress conditions,the relative conductivity of rice leaves increased.It is decreased that POD and CAT enzyme activities,chlorophyll-a,chlorophyll-b and total chlorophyll content,and soluble sugar content.The application of silicon preparations significantly improved the stress resistance of rice leaves at the tassel stage.And among the three silicon preparations,Si-60G had the best effect under alkaline salt stress conditions,but Si-50G under neutral salt stress conditions.Under alkaline salt stress conditions,it is Si-60G increased that chlorophyll-a content by 35.8%-41.4%,chlorophyll-b content by 19.0%-21.7%,total chlorophyll content by 32.2%-36.9%,soluble sugar content by 16.3%-16.4%,CAT enzyme activity by13.4%-15.0%,POD enzyme activity by 43.9%-45.9%.And Si-60G also reduced relative conductivity by 23.7%-24.3%and malondialdehyde content by 28.9%-31.2%,under alkaline salt stress conditions.Under neutral salt stress conditions,Si-50G increased soluble sugar content by14.9%-28.2%,CAT enzyme activity by 11.1%-23.1%,POD enzyme activity by 29.1%-38.6%.And Si-50G reduced relative conductivity by 11.5%-15.7%,and malondialdehyde content by17.3%-18.0%,under neutral salt conditions.（3）Under both neutral and alkaline salt stress conditions,it increased soil bulk weight and conductivity and reduced the percentage of large soil aggregates（>0.25 mm）.It can increase soil p H under alkaline salt stress.The application of silicon preparations had a significant improvement（P<0.05）on soil physicochemical properties at low concentrations,while most indicators were not significant（P>0.05）at high concentrations.At the same time,silicon preparations have inconsistent effects on p H.Under alkaline salt stress conditions,Si-60G significantly reduced soil bulk weight by 3.2%-4.1%,electrical conductivity by 12.8%,p H 1.4%,and increased the percentage of soil macroaggregates by 1.8%.Under neutral salt stress conditions,Si-TG reduced soil bulk weight by 4.6%,but increased p H 0.7%.And Si-50G reduced soil conductivity by3.5%-9.6%.（4）Under both neutral and alkaline salt stress conditions,rice yield,effective spike number,fruit set rate,spike grain number,and thousand grain weight were reduced.The application of silicon preparations was able to significantly enhance yield and composition factors（P<0.05）.Under alkaline salt stress conditions,Si-60G increased yield better than Si-50G and Si-TG;while,under neutral salt stress conditions,Si-50G and Si-TG better than Si-60G.Under alkaline salt stress conditions,Si-60G was able to increase the yield by 7.35%-10.75%,the effective number of spikes by 0.72%-1.03%,the number of grains by 14.90%-19.98%,and the thousand grain weight by 11.91%-12.15%.Under neutral salt stress conditions,Si-50G was able to increase yield by5.93%-7.79%and thousand grain weight by 7.29%-7.57%;Si-TG increased effective spike number by 15.45%（low concentration）,fruit set rate by 5.53%（low concentration）and grain number by10.50%-16.24%.In summary,it is recommended that Si-60G is best applied under alkaline salt stress conditions.And Si-50G is best used under neutral salt stress conditions. |
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