铅对旱地红壤脱氢酶活性的影响

Effects of Lead on Dehydrogenase Activity in Dry and Red Soil

通过实验室培养试验研究外源添加单一重金属铅(Pb)在不同浓度和培养时间下对旱地红壤脱氢酶活性的影响。结果表明,在旱地红壤中,当Pb浓度低于200 mg/kg土时,脱氢酶活性随浓度的增加而上升,在100 mg/kg土时活性最大;当Pb浓度大于200mg/kg土时,其活性随着Pb浓度的升高而逐渐降低,且浓度越高对脱氢酶活性的抑制作用愈显著。即200 mg/kg土可作为Pb对脱氢酶活性影响的临界浓度。此外,脱氢酶活性随培养时间的变化而呈现类似的变化,在培养10 d以前为促进作用,以后随培养时间的推移而日渐受到抑制,第10天可为脱氢酶活性受Pb胁迫的临界期。

The change of dehydrogenase activity（DA） in the dry and red soil was researched under different concentrations,single heavy metal,Pb added to the soil and under different incubation periods,which was under incubation experiment in the laboratory.The results showed that in the dry and red soil DA was enhanced with Pb concentration increased below 200 mg/（kg·soil）.DA had a peak value when Pb concentration was 100 mg/（kg·soil）.DA dropped gradually when Pb concentration was over 200 mg/（kg·soil）.DA was restrained more obviously when Pb concentration was larger over 200 mg/（kg·soil）.So 200 mg/（kg·soil） Pb concentration was a watershed to DA in different concentrations.Furthermore,there was a similar change with above different concentrations during different incubation periods.DA was accelerated before incubating 10 days and decreased little by little from incubating 10-60 days.Thus,the incubating 10th day might be a watershed period on Pb effecting DA under the different incubation time.