| 马丽娟,张慧敏,侯振安,闵伟.长期咸水滴灌对土壤氨氧化微生物丰度和群落结构的影响[J].农业环境科学学报,2019,38(12):2797-2807. |
| 长期咸水滴灌对土壤氨氧化微生物丰度和群落结构的影响 |
| Effects of long-term saline water drip irrigation on the abundance and community structure of ammonia oxidizers |
| 投稿时间：2019-05-30 |
| DOI：10.11654/jaes.2019-0604 |
| 中文关键词: 咸水滴灌 氨氧化古菌 氨氧化细菌 硝化势 群落结构 |
| 英文关键词: saline water drip irrigation ammonia-oxidizing archaea ammonia-oxidizing bacteria nitrification rate community structure |
| 基金项目:国家自然科学基金项目（41661055） |
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| 摘要点击次数: 1712 |
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| 中文摘要: |
| 为探讨长期咸水滴灌对棉田土壤氨氧化细菌（AOA）和氨氧化古菌（AOB）的丰度和群落结构的影响，于2018年采集已经过10年咸水滴灌的棉田土壤，通过实时荧光定量PCR和高通量测序技术测定土壤AOA和AOB的丰度和群落结构。试验设3个灌溉水盐度水平：0.35、4.61 dS·m-1和8.04 dS·m-1（分别代表淡水、微咸水和咸水）。结果表明：微咸水、咸水灌溉显著降低土壤NO3--N含量和潜在硝化势（PNR），但显著增加土壤盐分和NH4+-N含量。不同处理AOA和AOB的amoA基因拷贝数分别为2.2×106~3.6×106copies·g-1和1.9×105~3.2×105 copies·g-1干土；微咸水、咸水处理AOA和AOB amoA基因拷贝数均显著低于淡水处理，且微咸水处理显著降低AOA/AOB。PNR与AOA丰度（P<0.001）和AOB丰度（P<0.001）均呈显著正相关关系。此外，不同灌溉水盐度下AOA群落操作分类单元（OTUs）的数量大于AOB，微咸水、咸水灌溉显著降低AOB群落的OTUs。与淡水处理相比，咸水、微咸水处理显著增加AOA群落的香农指数，咸水处理显著降低AOB群落的香农指数。AOA和AOB群落的优势类群分别为Candidatus Nitrosocaldus和Nitrosospira；咸水、微咸水处理抑制AOA群落的Betaproteobacteria生长，而咸水处理中Candidatus Nitrosocaldus显著高于淡水和微咸水处理。AOB群落中Nitrosomonas的相对丰度随着灌溉水盐度的增加而显著降低。LEf Se分析显示，AOA在咸水灌溉下仅有1个差异物种，而AOB在微咸水灌溉时有5个差异物种。冗余分析结果显示：AOA群落结构的改变与土壤NO3--N、pH和盐度的变化密切相关，而AOB群落结构的改变仅与NO3--N和pH显著相关。盐分是影响氨氧化微生物生长及群落结构的主导因素，AOA和AOB共同参与土壤硝化作用，淡水、微咸水灌溉条件下AOB可能是硝化作用主导微生物种群，而咸水灌溉条件下AOA可能是主导微生物种群。 |
| 英文摘要: |
| Ammonia-oxidizing microorganisms are the main drivers of soil nitrification. However, little is known about the effects of saline water irrigation on the ammonia-oxidizing archaea(AOA)and ammonia-oxidizing bacteria(AOB)communities and their relative contribution to soil nitrification. Toward this end, a 10-year field experiment was conducted to evaluate the effects of long-term saline water irrigation on AOA and AOB in alluvial gray desert soil. The experimental design comprised three irrigation water salinity levels established at 0.35, 4.61, and 8.04 dS·m-1, representing freshwater, brackish water, and saline water, respectively. Irrigation with brackish water and saline water reduced the soil NO3--N content and potential nitrification rate(PNR), while the soil salinity and NH4+-N content increased markedly. The amoA gene copy numbers of AOA and AOB were in the range of 2.2×106~3.6×106 and 1.9×105~3.2×105 copies·g-1dry soil, respectively. Irrigation with brackish and saline water decreased the amoA gene copy numbers of AOA and AOB. The AOA/AOB ratios were 11.3 and 11.2 in the freshwater and saline water treatments, respectively, indicating that more brackish water irrigation decreased the AOA/AOB ratios. Moreover, the PNR was positively correlated with AOA and AOB abundance(P<0.001). The number of operational taxonomic units (OTUs)of AOA based on the amoA gene was larger than that of AOB under different irrigation water salinity treatments. Irrigation with brackish and saline water significantly decreased the OTUs of AOB. Compared with freshwater irrigation, irrigation with brackish and saline water significantly increased the Shannon diversity index of AOA, while saline water treatment significantly reduced the Shannon index of AOB. The dominant groups of the AOA and AOB communities were Candidatus Nitrosocaldus and Nitrosospira, respectively. Irrigation with saline and brackish water inhibited the growth of Betaproteobacteria in the AOA community, while the abundance of Candidatus Nitrosocaldus in irrigation with saline water was significantly higher than that under irrigation with freshwater and brackish water. The relative abundance of Nitrosomonas in the AOB community decreased significantly with increasing salinity of the irrigation water. Lefse analysis revealed only one differential species in AOA under irrigation with saline water, while five differential species were detected in AOB under irrigation with brackish water. Redundancy analysis showed that the variations in AOA community structure were closely associated with the changes in soil NO3--N, pH, and salinity, whereas the AOB community structure was only significantly correlated with NO3--N and pH. In conclusion, salinity was the dominant factor affecting the growth of ammonia-oxidizing microorganisms and community structure. AOB may be the dominant microbial population of nitrification with freshwater and brackish water irrigation, while AOA may be the dominant microbial population with saline water irrigation. These results can provide a scientific basis for further exploring the response mechanism of ammonia-oxidizing microorganisms and their roles in nitrogen transformation in the agricultural soils of arid areas. |
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