微生物驱动的硝化作用是氮循环的关键过程。土壤氨氧化作用是硝化作用的第一步,也是硝化作用的限速步骤,施氮是影响土壤氨氧化微生物的重要因素。因此,明确不同氮肥种类(尿素、硫酸铵和硝酸钾)对土壤氨氧化微生物群落与硝化势的影响,可...微生物驱动的硝化作用是氮循环的关键过程。土壤氨氧化作用是硝化作用的第一步,也是硝化作用的限速步骤,施氮是影响土壤氨氧化微生物的重要因素。因此,明确不同氮肥种类(尿素、硫酸铵和硝酸钾)对土壤氨氧化微生物群落与硝化势的影响,可以为缓解农田氮素流失和改善氮素循环提供参考。本研究以钙质紫色土为研究对象,采用盆栽试验,设置不施氮肥(CK)、施尿素(UR)、施硫酸铵(AS)和施硝酸钾(PN) 4个处理。通过测定不同类型氮肥处理下土壤化学性质、硝化势、土壤氨氧化细菌(AOB)和氨氧化古菌(AOA)的群落结构及α多样性,明确不同类型氮肥对土壤氨氧化作用的影响。结果表明,与CK处理相比,AS和UR处理下土壤pH分别显著降低2.52和0.32个单位(P<0.05),AS和UR处理下土壤全氮和铵态氮(NH_(4)^(+)-N)含量分别显著提升53.6%~83.0%和1 359.5%~1 740.4%(P<0.05);3种施氮处理下土壤碱解氮和硝态氮(NO_(3)^(-)-N)含量分别显著增加164.9%~233.1%和434.6%~1 485.3%(P<0.05);AS处理土壤速效磷含量显著降低33.7%(P<0.05);AS和UR处理下土壤碳氮比(C/N)分别显著降低40.0%和20.0%(P<0.05);各处理间土壤有机碳(SOC)含量无显著差异;AS处理土壤硝化势显著降低42.0%(P<0.05),UR和PN处理土壤硝化势分别显著提升292.0%和62.6%(P<0.05)。与CK处理相比,AS和UR处理下AOA amo A基因丰度分别显著提高84.1%和44.4%(P<0.05),AS处理AOB amo A基因丰度显著降低44.0%(P<0.05),UR处理显著提高1 821.3%(P<0.05)。冗余分析显示:土壤pH和NH_(4)^(+)-N含量为AOA群落结构的主要影响因子,C/N、土壤有机碳(SOC)和碱解氮为AOB群落结构的主要影响因子(P<0.05)。逐步回归分析显示:NH_(4)^(+)-N和碱解氮为AOA amo A基因丰度的主要影响因子(P<0.001),速效磷和碱解氮为AOB amo A基因丰度的主要影响因子(P<0.001)。偏最小二乘法分析显示:AOB amo A基因丰度、SOC、速效磷、碱解氮和pH对土壤硝化势具有显著影响(P<0.05)。综上,施用硫酸铵会显著降低土壤硝化势,而施用尿素会增加土壤硝化势,且AOB群落为钙质紫色土中氨氧化作用的主要驱动者,施用硫酸铵主要通过增加碱解氮含量,降低速效磷含量和AOB amo A基因丰度,降低硝化势;而施用尿素主要通过增加碱解氮含量和AOB amo A基因丰度,最终增加硝化势。展开更多
Manganese(Mn),an essential trace element in the human body,plays critical roles in many biological processes.Recent studies have discovered that Mn^(2+)may promote or directly activate the cGAS-STING pathway,thereby s...Manganese(Mn),an essential trace element in the human body,plays critical roles in many biological processes.Recent studies have discovered that Mn^(2+)may promote or directly activate the cGAS-STING pathway,thereby subsequently initiating the natural immune response and augmenting antitumor therapy.However,the current lack of accurate methods for Mn^(2+)determination in cells significantly limits their mechanism investigation;hence,it is urgent to establish novel tools to detect Mn^(2+)in cells.In this study,the dual-emission carbon dots were initially synthesized via the one-pot hydrothermal method employing L-aspartic acid and p-phenylenediamine as raw materials.In the presence of Mn^(2+),the emission peak centered at 350 nm exhibited significant enhancement,whereas another peak at 610 nm remained stable.Consequently,a ratiometric sensor for Mn^(2+)determination was established using the signal at 350 nm as the responsive signal and the signal at 610 nm as an internal reference.Under the optimal condition,a good linear relationship was achieved between the F350/F610 value and Mn^(2+)concentration ranging from 0.9 to 15μmol/L,with a calculated LOD of 61 nmol/L.Benefiting from the special Mn^(2+)-induced ratiometric approach,this method demonstrates outstanding sensitivity,selectivity,and stability,rendering it applicable for Mn^(2+)determination in complex biological samples,as well as Mn^(2+)imaging in MKN-45 and LO2 cells.展开更多
文摘微生物驱动的硝化作用是氮循环的关键过程。土壤氨氧化作用是硝化作用的第一步,也是硝化作用的限速步骤,施氮是影响土壤氨氧化微生物的重要因素。因此,明确不同氮肥种类(尿素、硫酸铵和硝酸钾)对土壤氨氧化微生物群落与硝化势的影响,可以为缓解农田氮素流失和改善氮素循环提供参考。本研究以钙质紫色土为研究对象,采用盆栽试验,设置不施氮肥(CK)、施尿素(UR)、施硫酸铵(AS)和施硝酸钾(PN) 4个处理。通过测定不同类型氮肥处理下土壤化学性质、硝化势、土壤氨氧化细菌(AOB)和氨氧化古菌(AOA)的群落结构及α多样性,明确不同类型氮肥对土壤氨氧化作用的影响。结果表明,与CK处理相比,AS和UR处理下土壤pH分别显著降低2.52和0.32个单位(P<0.05),AS和UR处理下土壤全氮和铵态氮(NH_(4)^(+)-N)含量分别显著提升53.6%~83.0%和1 359.5%~1 740.4%(P<0.05);3种施氮处理下土壤碱解氮和硝态氮(NO_(3)^(-)-N)含量分别显著增加164.9%~233.1%和434.6%~1 485.3%(P<0.05);AS处理土壤速效磷含量显著降低33.7%(P<0.05);AS和UR处理下土壤碳氮比(C/N)分别显著降低40.0%和20.0%(P<0.05);各处理间土壤有机碳(SOC)含量无显著差异;AS处理土壤硝化势显著降低42.0%(P<0.05),UR和PN处理土壤硝化势分别显著提升292.0%和62.6%(P<0.05)。与CK处理相比,AS和UR处理下AOA amo A基因丰度分别显著提高84.1%和44.4%(P<0.05),AS处理AOB amo A基因丰度显著降低44.0%(P<0.05),UR处理显著提高1 821.3%(P<0.05)。冗余分析显示:土壤pH和NH_(4)^(+)-N含量为AOA群落结构的主要影响因子,C/N、土壤有机碳(SOC)和碱解氮为AOB群落结构的主要影响因子(P<0.05)。逐步回归分析显示:NH_(4)^(+)-N和碱解氮为AOA amo A基因丰度的主要影响因子(P<0.001),速效磷和碱解氮为AOB amo A基因丰度的主要影响因子(P<0.001)。偏最小二乘法分析显示:AOB amo A基因丰度、SOC、速效磷、碱解氮和pH对土壤硝化势具有显著影响(P<0.05)。综上,施用硫酸铵会显著降低土壤硝化势,而施用尿素会增加土壤硝化势,且AOB群落为钙质紫色土中氨氧化作用的主要驱动者,施用硫酸铵主要通过增加碱解氮含量,降低速效磷含量和AOB amo A基因丰度,降低硝化势;而施用尿素主要通过增加碱解氮含量和AOB amo A基因丰度,最终增加硝化势。
基金Supported by National Natural Science Foundation of China(22264023)Natural Science Foundation of Shaanxi Province(2024JC-YBQN-0150)+2 种基金Yan'an Science and Technology Bureau Project(2023-SFGG-057)Scientific Research Projects of Education Department of Shaanxi Province(22JK0614)PhD Start Fund of Yan'an University(YDBK2022-15)。
文摘Manganese(Mn),an essential trace element in the human body,plays critical roles in many biological processes.Recent studies have discovered that Mn^(2+)may promote or directly activate the cGAS-STING pathway,thereby subsequently initiating the natural immune response and augmenting antitumor therapy.However,the current lack of accurate methods for Mn^(2+)determination in cells significantly limits their mechanism investigation;hence,it is urgent to establish novel tools to detect Mn^(2+)in cells.In this study,the dual-emission carbon dots were initially synthesized via the one-pot hydrothermal method employing L-aspartic acid and p-phenylenediamine as raw materials.In the presence of Mn^(2+),the emission peak centered at 350 nm exhibited significant enhancement,whereas another peak at 610 nm remained stable.Consequently,a ratiometric sensor for Mn^(2+)determination was established using the signal at 350 nm as the responsive signal and the signal at 610 nm as an internal reference.Under the optimal condition,a good linear relationship was achieved between the F350/F610 value and Mn^(2+)concentration ranging from 0.9 to 15μmol/L,with a calculated LOD of 61 nmol/L.Benefiting from the special Mn^(2+)-induced ratiometric approach,this method demonstrates outstanding sensitivity,selectivity,and stability,rendering it applicable for Mn^(2+)determination in complex biological samples,as well as Mn^(2+)imaging in MKN-45 and LO2 cells.
