| 钝化剂对镉污染土壤氮转化关键功能微生物群落结构的影响 |
| 摘要点击 214 全文点击 6 投稿时间：2025-02-17 修订日期：2025-07-14 |
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| 中文关键词 石灰 生物炭 镉（Cd） 固氮菌 氨氧化微生物 |
| 英文关键词 lime biochar cadmium （Cd） nitrogen-fixing bacteria ammonia-oxidizing microorganisms |
| DOI 10.13227/j.hjkx.202502114 |
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| 中文摘要 |
| 施加钝化剂是一种典型的土壤重金属污染修复方式，该过程不仅影响重金属的有效性，也能改变氮转化过程. 然而，关于钝化剂对镉污染土壤氮转化功能微生物群落结构的影响尚不明确. 通过施加典型的钝化剂（石灰和生物炭），开展镉污染土壤油菜盆栽实验，采用高通量测序等方法，探究土壤固氮菌和氨氧化菌基因丰度、群落特征的转变规律及其影响因子. 结果表明，施加石灰后，固氮菌、氨氧化古菌（AOA）和氨氧化细菌（AOB）的Shannon指数分别显著降低了8.62%、 9.11%和82.80%，Simpson指数分别显著增加了22.78%、3.56%和55.86%；而施加生物炭后，仅AOB的Shannon指数显著降低了80.13%，Simpson指数显著增加了71.63%. 施加石灰显著增加了AOA amoA基因丰度，显著降低了AOB amoA基因丰度，施加生物炭无显著变化. 施加石灰显著改变了固氮菌、AOA和AOB的β多样性，而施加生物炭仅显著改变了AOA的β多样性. 说明施加钝化剂能改变土壤氮转化相关微生物的群落结构，相比生物炭处理，石灰的作用影响较大. 此外，施加钝化剂显著影响了各功能微生物优势菌群（变形菌和泉古菌等）的相对丰度. 氮转化关键功能微生物群落结构的变化与土壤理化性质密切相关，固氮菌主要影响因子为pH和有效镉（ACd）；AOA主要影响因子为ACd和pH；AOB主要影响因子为有机质（SOM）、pH和ACd. 在固氮菌群落中，地杆菌（Geobacter）与ACd、NH4+和NO3-呈显著正相关，而与pH呈显著负相关；Azohydromonas则呈现相反的响应模式. AOA中，泉古菌（Crenarchaeota）和奇古菌（Thaumarchaeota）与pH显著正相关而与ACd负相关，而亚硝化球属（Nitrososphaera）与pH显著负相关，与土壤全氮（STN）呈正向关联. 对于AOB，β变形菌（β-Proteobacteria）等类群与ACd、NH4+和NO3-显著正相关，而与pH负相关. 通过说明施加钝化剂（尤其石灰）显著改变土壤氮转化关键功能微生物群落结构，研究结果可为深入理解钝化剂对Cd污染土壤氮转化过程的影响机制提供理论依据. |
| 英文摘要 |
| The application of passivators represents a typical remediation strategy for soil heavy metal pollution， a process that not only affects heavy metal bioavailability but also modifies nitrogen transformation processes. However， the influence of passivators on the structure of functional microbial communities governing nitrogen transformation in cadmium （Cd）-contaminated soils remains poorly understood. In this study， typical passivators （lime and biochar） were applied in a pot experiment with rapeseed cultivated in Cd-contaminated soil. High-throughput sequencing and complementary methodologies were employed to investigate shifts in gene abundance and community characteristics of soil nitrogen-fixing bacteria and ammonia-oxidizing microorganisms， along with their driving factors. The results revealed that lime application significantly reduced the Shannon index of nitrogen-fixing bacteria， ammonia-oxidizing archaea （AOA）， and ammonia-oxidizing bacteria （AOB） by 8.62%， 9.11%， and 82.80%， respectively， while increasing their Simpson index by 22.78%， 3.56%， and 55.86%. In contrast， biochar application exclusively reduced the Shannon index of AOB by 80.13% and increased its Simpson index by 71.63%. Lime significantly enhanced AOA amoA gene abundance but reduced AOB amoA gene abundance， whereas biochar induced no significant changes in amoA genes. Lime markedly altered the β-diversity of nitrogen-fixing bacteria， AOA， and AOB， while biochar only significantly affected AOA β-diversity. These findings demonstrate that passivators can restructure soil microbial communities involved in nitrogen transformation， with lime exerting more substantial effects than biochar. Additionally， both passivators significantly modified the relative abundance of dominant microbial groups （e.g.， Proteobacteria and Crenarchaeota） within functional communities. Changes in key nitrogen-transforming microbial communities showed strong correlations with soil physicochemical properties： Nitrogen-fixing bacteria were primarily governed by pH and available Cd （ACd）； AOA by ACd and pH； and AOB by soil organic matter （SOM）， pH， and ACd. Within nitrogen-fixing bacteria， Geobacter exhibited significant positive correlations with ACd， NH4+， and NO3- but a negative correlation with pH， while Azohydromonas displayed inverse responses. Among AOA， Crenarchaeota and Thaumarchaeota positively correlated with pH but negatively with ACd， whereas Nitrososphaera showed negative correlations with pH but positive associations with soil total nitrogen （STN）. For AOB， taxa such as β-Proteobacteria demonstrated positive correlations with ACd， NH4+， and NO3- but negative correlations with pH. By elucidating how passivators （particularly lime） significantly restructure key microbial consortia involved in soil nitrogen transformation， this study provides a theoretical foundation for understanding the mechanisms through which passivators influence nitrogen cycling processes in Cd-contaminated soils. |
