Dissimilatory nitrate reduction to ammonium and responsible microorganisms in two Chinese and Australian paddy soils
Dissimilatory nitrate reduction to ammonium and responsible microorganisms in two Chinese and Australian paddy soils
复制标题
DOI：
10.1016/s0038-0717(02)00049-4
复制
发表时间：
2002-08
影响因子：
9.7
通讯作者：
S.X Yin;D. Chen;L.M Chen;R. Edis
中科院分区：
文献类型：
--
作者：
S.X Yin;D. Chen;L.M Chen;R. Edis
研究了中国和澳大利亚两种典型水稻土中硝酸盐异化还原成铵（DNRA）及其相关微生物区系。在不添加任何外源碳源的条件下，DNRA对15 N标记硝酸盐的还原贡献率为14.9%，而对中国扬州土壤的贡献率仅为5%。添加还原剂（巯基乙酸钠和L-半胱氨酸）导致较低的氧化还原电位，并增强DNRA过程，与大部分的还原产物是铵。然而，氧化还原电位不能单独解释两种土壤DNRA电位的差异。添加葡萄糖也导致DNRA的大幅增加，特别是格里菲斯土壤，其中大部分产品是有机氮。Griffith土壤中DNRA含量显著高于扬州土壤，这与Griffith土壤中DNRA微生物种群数量显著高于扬州土壤相一致，也与Griffith土壤中活性碳含量显著高于扬州土壤相一致。相比之下，Griffith土壤中的真菌数量比扬州土壤中的小10倍左右。结果表明，土壤固有活性碳是影响硝酸盐还原在反硝化和DNRA之间分配的关键因素。分离到的DNRA细菌和芽孢杆菌大多为产芽孢细菌。
Dissimilatory nitrate reduction to ammonium (DNRA) and the responsible microflora were studied in two typical Chinese and Australian paddy soils. The DNRA accounted for 14.9% of total reduction of15N-labeled nitrate added to the soil from Griffith (NSW, Australia) under anaerobic incubation without any exogenous carbon source addition, but only 5% for the soil from Yangzhou (China). Addition of reducing agents (sodium thioglycollate and l-cysteine) resulted in lower redox potentials and enhanced the DNRA process, with the majority of the product of reduction being ammonium. However, redox potential alone could not explain the difference of DNRA potentials between the two soils. Additions of glucose also resulted in substantial increases in DNRA, especially for Griffith soil, with the majority of the product being organic-N. The significantly higher DNRA in Griffith soil compared to Yangzhou soil is consistent with the higher DNRA microorganism population isolated from Griffith soil than that in Yangzhou soil, which is also consistent with higher fraction of labile carbon in Griffith soil than that in Yangzhou soil. In contrast, the denitrifiers population in the Griffith soil was about 10-fold smaller than that in the Yangzhou soil. The results demonstrate that the soil indigenous labile carbon was the key factor influencing the partitioning of nitrate reduction between denitrification and DNRA. Most DNRA bacteria and denitrifiers isolated were spore-forming bacteria.