Short-term uptake of 15N by a grass and soil micro-organisms after long-term exposure to elevated CO2
Short-term uptake of 15N by a grass and soil micro-organisms after long-term exposure to elevated CO2
复制标题
DOI：
10.1007/s11104-005-2553-4
复制
发表时间：
2006-02-01
期刊：
影响因子：
4.9
通讯作者：
Leadley, PW
中科院分区：
文献类型：
--
作者：
Barnard, R;Barthes, L;Leadley, PW
这项研究考察了二氧化碳浓度升高对无机氮在草和土壤微生物之间短期分配的影响。将N-15标记的NH4+注入羊肚菌Holcus lanatus(L.)在重建的草原土壤中，在常温或高二氧化碳条件下种植了15个月以上。48h后，土壤微生物量氮中添加N-15的回收率随CO2浓度的升高而增加，在植物全氮中的回收率不变，在土壤可提取态氮中的百分比降低，但对植物氮含量和微生物量氮的影响不显著。这些结果和来自植物-微生物N-15分配实验的文献数据表明，控制CO2对短期和长期氮素吸收和周转的影响的机制不同。特别是，在二氧化碳浓度升高的情况下，土壤微生物短期固定添加的氮似乎不会导致土壤微生物生物量中氮的长期增加。此外，我们在二氧化碳升高时观察到的土壤微生物C：N比率的增加表明，长期暴露在二氧化碳中会改变这些微生物群落的功能或结构。
This study examines the effect of elevated CO2 on short-term partitioning of inorganic N between a grass and soil micro-organisms. N-15-labelled NH4+ was injected in the soil of mesocosms of Holcus lanatus (L.) that had been grown for more than 15 months at ambient or elevated CO2 in reconstituted grassland soil. After 48 h, the percentage recovery of added N-15 was increased in soil microbial biomass N at elevated CO2, was unchanged in total plant N and was decreased in soil extractable N. However, plant N content and microbial biomass N were not significantly affected by elevated CO2. These results and literature data from plant-microbial N-15 partitioning experiments at elevated CO2 suggest that the mechanisms controlling the effects of CO2 on short- vs. long-term N uptake and turnover differ. In particular, short-term immobilisation of added N by soil micro-organisms at elevated CO2 does not appear to lead to long-term increases in N in soil microbial biomass. In addition, the increased soil microbial C:N ratios that we observed at elevated CO2 suggest that long-term exposure to CO2 alters either the functioning or structure of these microbial communities.