摘要
以不同施肥方式、不同有机质含量的草甸棕壤和黑土4个土样为对象,研究了不同温度条件下,汞(Hg)对土壤脲酶动力学特征的影响.结果表明,同一类型、有机质含量高的土壤脲酶活性、酶促最大反应速度(Vmax)和Vmax/Km均高于有机质含量低的土壤,表明有机质对脲酶的吸附能力较强;黑土Vmax和Vmax/Km值总体上大于草甸棕壤,但酶活性和米氏常数(Km)值在不同土壤类型之间规律性较差,反映出酶活性由总酶量和酶-底物亲和力等因素共同决定;黑土Km值大小与有机质含量相一致,而草甸棕壤则相反,表明有机质含量和施肥方式均会对Km值产生影响;在最适温度以下,随温度升高,土壤的脲酶活性、Vmax和Vmax/Km值均增加;Hg对土壤脲酶表现出典型的反竞争性抑制现象;Hg对脲酶活性的抑制作用及对Km、Vmax和Vmax/Km的负效应均随温度升高而有增加的趋势,揭示出土壤对脲酶的保护能力随温度升高而有所下降.
Urease kinetics inhibited by Hg in two meadow burozem, fertilized by different ways and two phaeozem soils with different organic matter content was investigated at different temperatures. The results showed that the urease activity and kinetic parameter Vmax and Vmax/Km were higher in soils with high organic matter content than that in soils with low organic matter among the same soil type. it indicated that organic matter had great adsorption capacity to urease. Soil urease Vmax and Vmax/Km in phaeozem were generally higher than that in meadow burozem, but urcasc activity and Km were not comparable among different soil types. Km depended on not only the organic matter content of soils, but also fertilization ways. As incubating temperature increased, urease activity, Vmax and Vmax/Km value enhanced under the optical catalysis temperature. Hg behaved as uncompetitive inhibitor to soll urease in this experiment. The negative effect that Hg inhibited urease activity, Km, Vmax and Vmax/Km increased with temperature increasing, indicated that the protective capacity of soil on urease decreased with the temperature increasing.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2007年第2期278-282,共5页
Environmental Science
基金
国家重点基础研究发展规划(973)项目(2004CB418506)
国家自然科学基金重点项目(20337010)
国家自然科学基金项目(40301022)
沈阳大学沈阳环境工程重点实验室基金项目(0420)
关键词
土壤
脲酶
动力学
汞
温度
soil
urease
kinetics
Hg
temperature
