Relative contributions of bacteria and fungi to nitrous oxide emissions following nitrate application in soils representing different land uses
Relative contributions of bacteria and fungi to nitrous oxide emissions following nitrate application in soils representing different land uses
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DOI：
10.1016/j.ibiod.2021.105199
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发表时间：
2021-04
影响因子：
4.8
通讯作者：
A. Castellano‐Hinojosa;K. Le Cocq;A. Charteris;Maïder Abadie;D. Chadwick;I. Clark;J. González-López;E. Bedmar;L. Cárdenas
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作者：
A. Castellano‐Hinojosa;K. Le Cocq;A. Charteris;Maïder Abadie;D. Chadwick;I. Clark;J. González-López;E. Bedmar;L. Cárdenas
细菌和真菌在反硝化过程中会产生一氧化二氮（N2 O），但在土壤中施用硝酸盐（NO3−）后，它们的作用还没有明确确定。在微宇宙实验中，细菌和真菌的相对贡献N2 O和CO2（CO2）的产生后，4个不同的土地利用的对比土壤KNO 3的研究。每天将土壤润湿至80%水填充孔隙空间（WFPS），并在温室条件下保持10天。杀真菌剂放线菌酮和链霉素被用来确定可能的微生物来源的N2 O和CO2的排放。采用抑制剂加和比（IAR）评价了抗生素对N2 O和CO2排放的非靶效应。细菌和真菌群落的丰度分别通过细菌16 S rRNA基因和真菌内部转录间隔区（ITS）区域的定量PCR（qPCR）进行估计。通过对nirK、nirS、norB、nosZI和nosZII基因的定量分析，计算出细菌生长因子的基因拷贝数。10 d后，无论土壤类型如何，放线菌酮和链霉素处理的土壤N2 O累积排放量相似。在培养的前48-96 h内，施用杀菌剂的土壤N2 O通量均大于施用有机肥的土壤，平均为1.8 ± 0.3倍。在96 ~ 240 h内，抑菌土壤中的N2 O排放量比杀菌剂处理土壤中的N2 O排放量高（平均1.7 ± 0.2倍）。平均而言，68.5%的总CO2排放量在10天的潜伏期内产生的杀菌剂和31.5%，在那些处理过的土壤中的杀菌剂。在最初的48-96 h内，细菌对N2 O的贡献大于真菌，这可能是由于细菌对硝酸盐的利用更快。细菌16 S rRNA基因、ITS区和nirK、nirS、norBandnosZI细菌反硝化基因丰度的变化表明，用于防止细菌和真菌生长的抗生素在孵育期间是有效的。这些结果表明，细菌和真菌应考虑在土壤中设计和应用温室气体减排策略时，其相对贡献产生N2 O和CO2可以随时间和硝酸盐的可用性。
Bacteria and fungi have been shown to produce nitrous oxide (N2O) during denitrification, but their contribution after nitrate (NO3−) application to soil is not clearly established. In a microcosm experiment, the relative contribution of bacteria and fungi to N2O and carbon dioxide (CO2) production by four contrasting soils representing different land uses after KNO3addition was studied. The soils were daily wetted to 80% water-filled pore space (WFPS) and kept under greenhouse conditions for 10 days. The fungicide cycloheximide and the bactericide streptomycin were used to determine the possible microbial origin of the N2O and CO2emissions. Non-target effects of the antibiotics on the emission of N2O and CO2were evaluated using the inhibitor additivity ratio (IAR). The abundance of the bacterial and fungal communities was estimated by quantitative PCR (qPCR) of the bacterial 16S rRNA gene and the fungal internal transcribed spacer (ITS) region, respectively. The gene copy number of bacterial denitrifiers was calculated after quantification of thenirK,nirS,norB,nosZI andnosZII genes. After 10 d, regardless of the soil type, the cumulative N2O emission from the soils treated with cycloheximide or streptomycin were similar. In all the four soils, N2O fluxes were greater (on average 1.8 ± 0.3 times) in soils amended with the fungicide than with the bactericide during incubation for the first 48–96 h. Greater N2O emissions (on average 1.7 ± 0.2 times) were detected in soils where bacteria were inhibited in comparison to those treated with the fungicide from 96 to 240 h. On average, 68.5% of the total CO2emitted during the 10-d incubation period was produced in soils treated with the fungicide and 31.5% in those treated with the bactericide. The greater contribution of bacteria to the production of N2O than fungi during the first 48–96 h was possibly due to a faster used of nitrate. Variations in the abundance of bacterial 16S rRNA genes, the ITS region, and thenirK,nirS,norBandnosZI bacterial denitrification genes indicated that the antibiotics used to prevent the growth of bacteria and fungi were effective during incubation. These results suggest that both bacteria and fungi should be considered when designing and applying greenhouse gas mitigation strategies in soils and that their relative contribution to produce N2O and CO2can vary with time and nitrate availability.