重金属Cd处理对柱花草根际土壤酶活性的影响

Effects of Cadmium on the Soil Enzyme Activity of Stylosanthes at the Rhizoshpere Zones

采用添加外源重金属和土培盆栽法,研究了浓度为0～5.0 mg/kg的镉(Cd)对4个柱花草(热研2号、热研13号、TPRC2001-1和西卡柱花草)根际土壤酶(过氧化氢酶、脲酶、磷酸酶)活性的影响。结果表明,不同柱花草根际土壤过氧化氢酶活性对镉胁迫响应存在显著差异,镉促进4个柱花草根际土壤过氧化氢酶活性的浓度分别为0.5、1.0～5.0、0.5～5.0、2.0～5.0 mg/kg。与对照(CK)相比,低浓度Cd(0.5 mg/kg)胁迫,对热研2号、热研13号和西卡柱花草根际土壤脲酶活性无显著影响,但TPRC2001-1柱花草根际土壤脲酶活性增加;而在1.0～5.0 mg/kg处理条件下,脲酶活性无显著变化。0.5～5.0 mg/kg Cd胁迫时,显著抑制了热研2号、热研13号和西卡柱花草根际土壤磷酸酶活性;2.0～5.0 mg/kg Cd胁迫时,TPRC2001-1柱花草根际土壤磷酸酶活性显著降低。说明,种植TPRC2001-1柱花草能缓解镉对3种土壤酶活性的胁迫,土壤镉对3种土壤酶活性的影响表现为磷酸酶>脲酶>过氧化氢酶,磷酸酶和脲酶可作为土壤中镉污染的指示酶。

The influence of Cd （0-5 mg/kg） addition on the activity of catalases, urase, phosphatase in four Stylosanthes soils was conducted by the use of pot experiment. The result showed that the responses of the enzymes in different Stylosanthes soils to the Cd stress were significantly different. The stimulated concentration of Cd to the soil catalases in the four Stylosanthes soils was 0.5, 1.0-5.0, 0.5-5.0 and 2.0-5.0 mg/kg, respectively. Compared with CK, effects of low Cd concentration on the activity of urase in the Reyan No.2, Reyan No.13 and Seca soil wasn＇t significantly different. While the activity of urase in the TPRC2001-1 was increased. The activity of urase didn＇t changed under the treatment of 1.0 mg/kg Cd. Stress of 0.5-5.0 mg/kg Cd could restrict the activity of phosphatase significantly in the Reyan No.2, Reyan No.13 and Seca soil, the activity of phosphatase was decreased under the stress of Cd concentration of 2.0-5.0 mg/kg. These results indicated that cultivation of TPRC2001-1 Stylosanthes could decrease the stress of Cd on the enzymes, effects of the soil Cd stress on the three kind of enzymes were： phosphatase〉urase〉catalases, Herein the phosphatase was the most sensitive enzyme to the Cd stress, Phosphatase and urase were served as the indicators for the Cd contamination.