Effect of Cadmium Stress on Wheat Rhizosphere Environment in Three Soil Textures during Filling Stage

The soil texture is one of the most important factors impacting on the rhizosphere environment of crops and heavy metals migration in field.With different concentrations of cadmium stress,the rhizosphere environment of wheat during filling stage was studied in pot experiment in screen house in order to find the difference of three soil textures.Many morphological and physiological indexes,including wheat root length,wheat root activity,soil urease activity,soil sucras activity,cadmium content in soil and wheat,were determined.The results showed that,when concentration of cadmium was lower than 40 mg/kg,wheat root length,wheat root activity,soil urease activity and soil sucras activity were all bigger than the control(0 mg/kg cadmium),but activities of different soil enzymes were inhibited when the concentration of cadmium was more than 60 mg/kg.Considering the soil texture,the growth of wheat root and the enzyme activities of soil in loam were better than in sandy soil and clay soil.Besides,total cadmium in three textures of soil was listed as loamclaysandy soil,available cadmium as sandy soilclayloam,cadmium in wheat root as sandy soilloamclay,and cadmium in wheat grain as sandy soilloamclay,which indicated that clay and loam had stronger adsorption ability to cadmium than sandy soil.And so,cadmium stress to wheat plants was more alleviated in clay and loam for less transport of cadmium than in sandy soil.In conclusion,cadmium pollution for grown wheat was less in loam and clay than in sandy soil.