丹麦森林土壤反硝化作用的动力学分析

本项研究将乙炔和氯霉素抑制技术结合起来 ,对丹麦一森林土壤的反硝化作用进行了研究 ,并考察温度对其还原酶活性的影响 .反硝化还原酶活性和合成过程受O2 的抑制 ,厌氧培养时 ,需要一定时间消耗系统中残余的O2 来解除这种抑制作用 .在无抗生素抑制蛋白质合成时 ,硝酸还原酶只有少量合成 ,而N2 O还原酶却显著地诱导产生 .这一结果对土壤吸收N2 O能力的研究具有重要意义 .在各处理下 ,系统中未发生亚硝酸盐的明显积累 ,表明亚硝酸还原酶活性大于硝酸还原酶 .外加葡萄糖加速了反硝化作用 ,并能促进酶的合成和消除还原过程中的电子竞争 .供试土壤表现出很强的厌氧呼吸作用 ,并受外加C源的促进 .反硝化作用的活化能低于土壤厌氧呼吸的活化能 ,因此反硝化作用的Q1 0值较低 ,CO2 和N2 O的产生比例随温度升高而加大 .

Dynamics of denitrification potential in a Danish forest soil.

The denitrification potential of a Danish forest soil is studied by the combination of acetylene and chloramphenicol inhibition techniques, and the effect of temperature on its related reduction enzyme activities is investigated.The activities and synthesis of reduction enzymes are inhibited by oxygen. It takes some time to consume the O 2 left in an anaerobic incubation to release this inhibition.When protein synthesis is not inhibited by antibiotic, nitrate reductase is synthesized slightly, while N 2O reductase is significantly induced, which is of significance to study the N 2O absorbing capacity of soil. Nitrite is not considerably accumulated in all treatments, indicating that the activity of nitrite reductase is higher than nitrate reductase. Denitrification is stimulated by adding glucose, while the synthesis of enzymes and the releasing of electron competitions in the reduction processes are probably promoted as well. There shows a strong anaerobic respiration in the sampled soil, which is stimulated by C source addition. The activation energy for denitrification is lower than that for anaerobic respiration, therefore, the Q 10 value for denitrification is lower, and the ratio between CO 2 and N 2O evolution is higher with temperature.