一株好氧反硝化细菌的分离与鉴定

本试验旨在从环境样品筛选出一株具有去除氨氮和亚硝酸盐氮的好氧反硝化细菌。通过对采集水样进行富集驯化,利用溴百里酚蓝(BTB)选择性培养基进行初筛,并以去除氨氮、亚硝酸盐氮能力为指标进行复筛,得到一株好氧反硝化细菌DG-3。在好氧条件下测定了菌株DG-3的反硝化能力,并对其进行了形态学观察、生理生化试验和16S rDNA基因序列的分析。菌株DG-3在好氧反硝化培养过程中对硝酸盐氮(138.63 mg/L)的去除率达75.57%,在整个培养过程中,仅出现了少量的亚硝酸盐氮累积,其最大累积值仅为2.06 mg/L。反硝化培养基培养及扫描电镜观察结果显示,菌株DG-3为杆状,无鞭毛,大小为(1.7~2.8)μm×(0.6~0.7)μm,菌落呈淡黄色。结合形态学、生理生化特性及16S rDNA同源性比对分析,初步判断菌株DG-3为门多萨假单胞菌(Pseudomonas mendocina)。菌株DG-3具有好氧反硝化能力,且能去除氨氮和亚硝酸盐氮,在水产养殖含氮废水的处理中具广阔的应用前景。     

一株脱氮细菌的分离鉴定及脱氮活性检测

利用硅胶平板从淤泥中分离到一株脱氮茵FX7，该菌株在好氧条件下具有降解亚硝态氮的能力。亚硝态氮初始浓度为2500mg／L时，该菌株在48h内亚硝态氮降解率为45％。通过形态学特征、生理生化特性及16SrDNA同源性比较对菌株FX7进行鉴定，初步判断其为假单胞菌（Pseudomonassp）。Pb^2＋、Hg^2＋和Cr^2＋对菌株FX7的亚硝态氮降解活性有很强的抑制作用，而低浓度的Zn^2＋和Fe^3＋对其活性有一定的激活作用。     

适用于猪场沼液处理的好氧反硝化菌筛选及其脱氮特性评价

试验旨在筛选适合于猪场沼液处理的好氧反硝化菌。从活性污泥中分离获得 16 株好氧反硝化菌,其中菌株 ZH-14 的总氮(TN)和硝酸盐氮的去除效果最好,分别达到 50.73%和 99.99%。该菌株经过平板形态观察、功能基因和 16S rDNA 基因分析,鉴定为施氏假单胞菌(Pseudomonas stutzeri)。结果表明:菌株 ZH-14 在硝酸钾为唯一氮源培养基中生长时,48 h 后硝酸盐氮与 TN 的降解率分别为 100%和41.76%;以亚硝酸钠为唯一氮源培养时,亚硝酸盐氮降解率为 99.24%;以氨氮为唯一氮源培养时,氨氮的降解率达 94.1%;使用菌株 ZH-14 处理畜禽沼液,当其接种终浓度为 107 CFU/mL 时,经过 48 h 处理,氨氮、硝酸盐氮和化学需氧量的去除率分别为 54.4%、97.7%和 77.9%。综上表明,菌株 ZH-14 具有较强的反硝化和处理猪场沼液的能力,具有良好的应用开发前景。     

猪场污水异养硝化-好氧反硝化菌筛选及性能研究

高氨氮含量是猪场污水达标处理的一大难点,传统生物脱氮工艺是在不同的工艺条件下分别进行硝化或反硝化作用,设施成本高且占地面积大,因此并不适合应用于猪场污水的处理.异养硝化-好氧反硝化(HN-AD)菌作为一类能同时进行硝化反应和反硝化反应的细菌,能较好解决硝化和反硝化不能同存一池的问题.本研究以猪场污水处理系统兼性塘中长期...     

Effects of thiosulfate addition on ammonia and nitrogen removal in biofilters packed with Oyaishi (pumice tuff)

Ammonia removal is achieved partly by absorption and nitrification in biofilters, resulting in the accumulation of nitrogen and the necessity of treating the effluent water. We investigated the effects of thiosulfate addition to a biofilter containing pumice tuff for ammonia and nitrogen removal in a laboratory‐scale experiment. The addition of thiosulfate to the circulating water led to a decreased nitrate and nitrite along with an increase of sulfate. The inorganic nitrogen in the circulating water decreased by up to 44% with thiosulfate addition compared to without thiosulfate. Batch experiments revealed that denitrification activity decreased exponentially along with increases in dissolved oxygen; however, approximately 30% of denitrification activity was maintained at dissolved oxygen concentration of 3.3 mg/L. Metabarcoding of 16S rRNA genes indicated that the genus Thiobacillus had a relative abundance of 0.002%–0.016% of total bacteria in the biofilter packing material. The circulating water pH was decreased below 5 with sulfur oxidation, and ammonium was accumulated without pH control resulting in a decrease in the relative abundance of the family Nitrosomonadaceae. Its relative abundance increased with control of pH to near neutral, indicating that ammonia‐oxidizing activity could be maintained by adjusting pH. Thiosulfate addition could stimulate nitrogen removal by sulfur‐dependent denitrification in biofiltration systems.     

硝化细菌的分离鉴定

应用硝化细菌选择性培养基,从南京的土壤和水体中筛选到6株硝化细菌,包括3株亚硝化菌和3株硝化菌,对其生理生化特性、温度敏感性、耐盐性、抗生素抗性、及硝化能力等生物学特性进行了测定。结果表明,6株细菌均为G-,菌体杆状或球状。生长缓慢,培养120 h以后才进入对数生长期,5 d左右形成菌落。最适生长温度为25~30℃。耐受偏碱环境。不耐盐,6株菌都能耐受的盐浓度范围是0.05%~0.3%。通气量对该菌的生长没有太大影响。6株菌株对不同的抗生素具有抗性。其中,菌株J2的抗药谱最窄,只抗卡那霉素。6株菌只能在以碳酸钠或者碳酸氢钠为唯一碳源、以硫酸铵或者亚硝酸盐为唯一氮源的培养基上生长良好。菌株硝化能力不同,其中菌株J2硝化能力较强,在基础培养基中200 h,该菌转化NO2-42%左右,可以作为降解鱼塘中和饲料中亚硝酸盐的硝化菌候选株。     

无脉苔草根际优良促生菌鉴定及其作用研究

采用钼蓝比色法(molybdenum blue colorimetry, MBC)、乙炔还原法(acetylene reduction assay, ARA)及高效液相色谱法(high performance liquid chromatography, HPLC)测定了分离自无脉苔草根际的6株根际促生菌溶磷、固氮及分泌激素的特性,并利用16S rDNA序列分析技术对筛选出的2株优良促生菌进行鉴定。结果表明,6株促生菌的溶磷量在298.17~554.67 mg/L之间,其中菌株TPRS3的溶磷能力最强(554.67 mg/L);6株促生菌中有4株具有固氮能力,固氮酶活性在170.19~456.87 nmol C₂H₄/(mL·h)之间,菌株TPRS19的固氮能力最强,固氮酶活性为456.87 nmol C₂H₄/(mL·h),菌株TRPS3和TPRS12无固氮能力;6株促生菌均具有分泌植物激素的能力,其中3-吲哚乙酸(IAA)分泌量在8.20~86.36 mg/L范围内,赤霉素(GA₃)在26.36~135.90 mg/L范围内,反-玉米素(t-Z)在9.55~141.68 mg/L范围内,菌株TPRS19分泌IAA的能力最强,为86.36 mg/L,菌株TPRS5分泌GA₃的能力最强,为135.90 mg/L,菌株TPRS2分泌t-Z的能力最强,为141.68 mg/L,菌株TPRS3、TPRS5、TPRS12和TPRS19兼具分泌3种激素能力。经鉴定,菌株TPRS5为枯草芽孢杆菌(Bacillus subtilis),菌株TPRS19为阴沟肠杆菌(Enterobacter cloacae),这2株菌有望作为研制微生物肥料的优良菌株。     

Research progress of Anammox-denitrification coupling start up and Influencing Factors

Since anammox can simultaneously remove ammonia and nitrite nitrogen,And low cost,have been researched by many scholars,It high ammonia wastewater treatment has great application value.However,high concentrations of organic carbon on anaerobic ammonium oxidation significantly inhibited.How to achieve anaerobic ammonium oxidation and denitrification coupling,is now a focus of research in the training process anammox bacteria and denitrifying bacteria on pH,organic matter with different requirements,this paper summarizes the anammox and denitrification startup method and pH,organic matter on anaerobic ammonia oxidation and denitrification coupling and explore control strategies for anaerobic ammonium oxidation and denitrification coupling recommendations.     

川西北高寒草甸植物根际促生菌筛选及其特性研究

为获得多功能的高寒植物根际促生菌（Plant growth-promoting rhizobacteria,PGPR）,并明确其生理生化特性,本研究采用选择性培养基法从川西北广泛分布的5种高寒草甸植物根际土壤和根系中分离了44株菌株,并对菌株的溶磷、固氮和解钾特性进行测定。结果显示：25株为溶无机磷菌株,24株为溶有机磷菌株,溶磷量分别在10.98～90.27 μg·mL^-1和10.58～64.56 μg·mL^-1之间;固氮菌株共20株,其固氮酶活性介于5.23～64.87 nmol（C₂H₄）·h^-1·mL^-1之间;解钾菌株21株,解钾量在9.23～73.21 μg·mL^-1之间。经过形态学和生理生化特征分析,最终筛选出12株兼具溶磷、固氮和解钾的多功能菌株,分子鉴定将其归属于不动杆菌属（Acinetobacter）、沙雷氏菌属（Serratia）、假单胞菌属（Pseudomoas）、芽孢杆菌属（Bacillus）、戴尔福特菌属（Delftia）和寡养单胞菌属（Stenotrophomonas）。研究结果可为川西北高原土壤微生物菌肥的开发提供优质菌源参考。     

高寒草地针茅内生菌265ZY3的生物学特性研究及其鉴定

对高寒草地针茅（Stipa capillata L.）内生细菌265ZY3进行了抗菌、产IAA、溶磷、固氮等生物学特性的研究,并通过16SrDNA序列分析对其进行了鉴定。结果表明：265ZY3对马铃薯坏疽病菌（Phomafoveata）、马铃薯炭疽病菌（Colletotrichum coccodes）和马铃薯枯萎病菌（Fusarium avenaceum）均有良好的抑制作用,抑菌率分别为81.65%,87.84%和72.64%;在不含色氨酸和含100mg·L^-1色氨酸的King培养液中分泌IAA的量分别为38.59mg·L^-1和42.33mg·L^-1;能溶解无机磷和有机磷,且溶解无机磷的能力是有机磷的68倍;同时,具有固氮能力。结合形态学特征,通过16SrDNA序列同源性分析,将265ZY3初步鉴定为解淀粉芽孢杆菌（Bacillus amyloliquefaciens）。     

高原早熟禾根际促生菌分离筛选及特性研究

为获得高原早熟禾（Poa alpigena L.）根际优良促生菌资源,从甘南草原采集高原早熟禾样品,从其根际分离筛选具有溶磷、固氮能力的促生菌株,研究其促生特性,并验证其对高原早熟禾种子萌发及幼苗生长的影响,在此基础上,运用16S rRNA基因分析法确定其分类地位。结果发现：共分离出32株具有促生作用的菌株,筛选出的5株优良菌株中溶解无机磷菌株有4株,溶有机磷菌株3株,固氮菌4株;5株菌株均具有分泌吲哚-3-乙酸（Indole-3-acetic acid,IAA）的能力,分泌量在9.62~76.16 μg·mL^-1之间;待测菌均能提高高原早熟禾幼苗的发芽率、发芽指数、幼苗活力指数,并能促进高原早熟禾幼苗的生长;分类地位鉴定结果表明5株菌中有2株枯草芽孢杆菌,1株蕈状芽孢杆菌,1株不动杆菌以及1株荧光假单胞菌。本研究为进一步的促生菌机理研究和功能微生物资源开发奠定了基础。     

不同形态氮肥对紫花苜蓿生长、硝酸盐转运蛋白基因MtNRT1.3表达及氮吸收的影响

为了探讨豆科牧草对不同形态氮素的吸收,以紫花苜蓿（Medicago sativa L.）为试验材料,通过盆栽试验探究不同形态氮肥对紫花苜蓿生长、硝酸盐转运蛋白基因MtNRT1.3表达和氮吸收的影响。试验设有4个处理,分别为不施氮处理（对照组,Con）、施铵态氮（NH₄Cl—T1）、硝态氮（NaNO₃—T2）和混合氮（铵态氮、硝态氮1：1混合—T3）,各形态氮肥施加总量为按纯氮250 mg（每1 kg土）。试验结果表明,施氮处理提高了紫花苜蓿中的氮含量,施加各种氮肥均提高了紫花苜蓿根中MtNRT1.3基因的表达量,且该基因的表达量与土壤铵态氮和硝态氮呈正相关性（P<0.01）。相比于铵态氮肥,施加硝态氮肥不但可增加植株中硝态氮含量,而且能提高植株铵态氮含量;相比于单施硝态氮和铵态氮肥,混合氮肥对提高植株氮含量效果最好;施加硝态氮肥更有利于紫花苜蓿地上部分生物量的累积。因此,对紫花苜蓿施加氮肥应重视铵态氮和硝态氮的比例,增加硝态氮的比例更有利于紫花苜蓿的生长和对氮素的吸收。     

灵芝漆酶在黑曲霉中的重组表达及发酵条件优化

【目的】 在黑曲霉（A.niger）中重组表达灵芝L菌漆酶基因，并对其发酵条件进行优化，旨在获得一株高产灵芝漆酶的黑曲霉基因工程菌。【方法】 从灵芝L菌克隆漆酶基因Lac-L，并根据黑曲霉密码子偏好性进行优化。选用黑曲霉糖化酶启动子（PglaA）、信号肽及终止子为表达原件，以米曲霉pyrG基因为筛选标记，构建漆酶表达盒，采用聚乙二醇-CaCl₂法将其转化至黑曲霉X1（ΔpyrG）原生质体中。对转化子进行PCR验证及固态发酵酶活测定，筛选高产漆酶重组菌株，并对阳性转化子固态发酵培养基碳源、无机与有机氮源比例、Cu²⁺浓度及发酵时间进行优化。【结果】 经尿嘧啶缺陷及含2，2'-联氮-双（3-乙基苯并噻唑啉-6-磺酸）二铵盐（2，2'-azinobis （3-ethylbenzothiazoline-6-sulfonic acid ammonium salt），ABTS）培养基筛选获得25株重组漆酶转化子，酶活复筛获得灵芝漆酶异源表达6号重组菌株，发酵72 h酶活可达3 532.6 U/kg，宿主菌株的酶活仅为58.37 U/kg。重组6号菌优化后的最适固态发酵条件为：以麸皮为基础培养基，添加2%麦芽糖、2%（NH₄）₂SO₄、0.25 g/L CuSO₄，发酵60 h时重组菌株产漆酶活力最高，达到6 255.47 U/kg。【结论】 在黑曲霉中成功实现灵芝L菌漆酶基因Lac-L的异源表达。     

连续施氮对马铃薯根际细菌群落结构及反硝化作用的影响

为了揭示连续施用不同氮量对半干旱地区马铃薯根际细菌群落结构及反硝化作用的影响。通过大田试验设置了6个不同施氮量处理:N₀(对照,不施氮)、N₇₅(施氮量75 kg·hm^-2)、N₁₅₀(施氮量150 kg·hm^-2)、N₂₂₅(施氮量225 kg·hm^-2)、N₃₀₀(施氮量300 kg·hm^-2)和N₃₇₅(施氮量375 kg·hm^-2),研究了连续5年不同施氮量对半干旱地区马铃薯根际细菌群落结构及反硝化作用过程中编码亚硝酸还原酶的关键酶基因nirK和nirS丰度的影响。结果显示:各处理土壤中$NO_{3}^{-}$ -N含量随施氮量的增加显著增加,最高施氮量处理(N₃₇₅)土壤中$NO_{3}^{-}$-N含量高达80.41 mg·kg^-1,分别比其他处理增加了86.87%~856.12%;土壤亚硝酸还原酶活性随着施氮量的增加随之增强,高氮处理显著高于低氮处理。高通量测序结果显示,大量施氮降低了细菌群落的Alpha多样性,显著改变了土壤细菌群落的物种组成;与N₀处理相比,其他各施氮处理根际土壤中变形菌门和厚壁菌门的相对丰度增加了1.66%~26.53%和22.59%~85.52%,放线菌门和酸杆菌门的相对丰度降低了3.48%~34.63%和4.21%~37.12%,高氮处理显著低于不施氮及低氮处理;高量施氮显著提高了根际土壤中Lactococcus、Bacillus和Lysobacter的相对丰度。根际土壤中nirK和nirS相对丰度随施氮量的增加随之增加,高氮处理中nirK和nirS相对丰度分别比N₀处理增加了116.26%、101.49%和28.24%、8.47%。Person相关性分析表明,nirK相对丰度与土壤$NO_{3}^{-}$-N含量呈显著正相关关系,pH与nirK和nirS的丰度呈显著负相关关系。大量施氮造成土壤剖面中$NO_{3}^{-}$-N积累量的增加以及pH值降低是引起根际细菌群落结构以及nirK和nirS丰度变化的主要原因。     

温度对紫外分光光度法测定生乳中亚硝酸盐含量的影响

本文通过研究温度对紫外分光光度法测定生乳中亚硝酸盐含量的影响,建立采用紫外分光光度法测定生乳中亚硝酸盐含量的方法。结果表明,此方法测定生乳中亚硝酸盐含量可以获得良好的线性关系,相关系数R²>0.99991,其拟合度较高,在加热温度95 ℃的条件下,3 个（0.1 mg/L、0.2 mg/L、0.3 mg/L）不同水平的加标平均回收率为91.00%、90.50%、92.17%,重复性试验RSD<5%。该方法操作简便,分析快速,亚硝酸盐提取速度快,适合生乳中亚硝酸盐含量的检测。     

根瘤菌与固氮菌联合对毛叶苕子的促生效果

利用前期筛选的具有优良固氮活性的巨大芽孢杆菌菌株N3和豌豆根瘤菌菌株Vic5,研究单一及复合接种对毛叶苕子的促生效果及对土壤性质的影响.结果表明:相比不接菌处理CK,单一接种N3能显著提高毛叶苕子根瘤固氮酶活性,单一接种Vic5能显著提高毛叶苕子地上部生物量、结瘤数和根瘤固氮酶活性,Vic5处理下毛叶苕子地上部生物量、...     

饲料维生素C含量对圆斑星鲽幼鱼抗氨氮胁迫能力的影响

氨氮污染是水产养殖中重要的污染物,因此提高鱼体抗污染应激能力至关重要。本试验采用不同维生素C含量的饲料饲喂圆斑星鲽幼鱼,探究饲料维生素C含量对圆斑星鲽幼鱼抗氨氮胁迫能力的影响。试验在(12.5±1.5)℃的水温下进行,选择体重为(38.0±0.8)g的健康圆斑星鲽幼鱼,随机分为7组(每组3个重复,每个重复30尾),分别投喂维生素C含量为10.2(对照)、249.1、402.8、616.2、769.5、909.4和1 177.8 mg/kg的试验饲料8周。投喂试验结束后,从每个重复取10尾鱼,用20 mg/L的氨氮胁迫24 h。结果表明:无论是氨氮胁迫前还是氨氮胁迫后,在饲料维生素C含量达到769.5 mg/kg时,肝脏和肌肉中维生素C积累达到饱和,再继续升高饲料维生素C含量,肝脏、肌肉中维生素C含量不再显著升高(P0.05)。除1 177.8 mg/kg维生素C组外,无论是氨氮胁迫前还是氨氮胁迫后,各维生素C添加组圆斑星鲽幼鱼血清中过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性均显著高于对照组(P0.05)。除616.2 mg/kg维生素C组血清中CAT活性无显著变化(P0.05)外,氨氮胁迫使各组血清中CAT和SOD活性显著降低(P0.05),但添加维生素C可以减少降低的幅度。无论是氨氮胁迫前还是氨氮胁迫后,各维生素C添加组鳃丝Na+/K+-ATP酶活性均显著高于对照组(P0.05)。氨氮胁迫使对照组及909.4和1 177.8 mg/kg维生素C组鳃丝Na+/K+-ATP酶活性显著降低(P0.05),其他组则无显著变化(P0.05)。氨氮胁迫使各组血清中葡萄糖和乳酸含量显著升高(P0.05),对照组血清中皮质醇含量显著升高(P0.05)。此外,氨氮胁迫使各组血清中总铁结合力显著降低(P0.05)。综合各项测定指标,圆斑星鲽幼鱼饲料中维生素C含量在402.8~616.2 mg/kg时可有效提高机体抗氨氮胁迫能力。     

Characteristics of Gas Generation (NH3, CH4, N2O, CO2, H2O) From Horse Manure Added to Different Bedding Materials Used in Deep Litter Bedding Systems

The aim of this study was to analyze the influence of horse manure added to different bedding materials on the generation of gases (ammonia (NH₃), nitrous oxide, carbon dioxide, methane, water vapor) from deep litter bedding under standardized laboratory conditions. Two different types of straw (wheat and rye) and wood shavings were analyzed. The deep litter (substrate) was made of 25 kg of the respective bedding material, 60 kg horse feces, and 60 L ammonium chloride solution (urea), and spread out in identical chambers over 19 days (n = 3). On days 1, 8, 15, and 19, total nitrogen, total carbon, and dry matter content of the substrate, as well as the pH in 500-g samples, were measured along with. At the end of each test period, the nitrite nitrogen, nitrate nitrogen, and ammonium nitrogen contents of the leachate were analyzed. The wheat straw substrate emitted the highest concentration of NH₃ (4.31 mg/m³; P < .0001) and the wood shavings substrate emitted the lowest (1.73 mg/m³; P < .0001); the rye straw substrate generated 3.05 mg/m³. In addition, significant differences occurred during days 1 to 3 with respect to the generation of the gases NH₃, methane, nitrous oxide, carbon dioxide, and water vapor, and after the opening of the chamber on day 15. The nitrogen losses through the leachate occurred mainly in the form of nitrate, where the leachate from the wheat straw substrate had a significantly higher amount of nitrate nitrogen (44.56 mg) as compared with the leachates of the rye straw (14.49 mg; P ≤ .0001) and the wood shaving substrates (22.62 mg; P = .0010).     

‘热研4号’王草替代紫花苜蓿对TMR发酵品质及有氧稳定性的影响

本试验旨在探讨不同比例‘热研4号’王草（Pennisetum purpureum×P.americana ‘Reyan No.4’）替代紫花苜蓿（Medicago sativa L.）对全混合日粮发酵品质及有氧稳定性的影响。试验设‘热研4号’王草替代比例为0%（H₀,紫花苜蓿对照组）,18%（H₁₈）,30%（H₃₀）,42%（H₄₂）4个处理,青贮60 d后开袋取样,分析其发酵品质和营养成分,并分别在有氧暴露的第0,3,6,9,12 d取样评定其有氧稳定性。结果表明：随着热研4号王草替代比例的增加,发酵全混合日粮中乳酸含量、pH及氨态氮/总氮逐渐减小,各组氨态氮/总氮小于100 g·kg^-1TN且均未检测到丁酸;发酵60d后,H₄₂组水溶性碳水化合物含量显著高于H₀,H₁₈组（P<0.05）,与发酵前相比,各组干物质和粗蛋白含量有所下降,H₄₂组干物质和粗蛋白含量下降最小;有氧暴露期间,好氧细菌、酵母菌和霉菌的数量逐渐增加,乳酸菌的数量逐渐降低,H₄₂组pH在12 d内未超过4.2,有氧稳定性最好。由经济效益分析可知,H₄₂组饲料成本最低。综上所述,选用H₄₂组进行全混合日粮发酵最为适宜。     

Effects of nitrogen forms on growth and nitrogen assimilation and utilization of Buchloe dactyloides北大核心CSCD

This research explored the nitrogen (N) uptake preference of Buchloe dactyloides, in order to improve the management of this species over the whole growth cycle. The experiment included two cultivars of B. dactyloides (‘Sundancer’ and ‘Texoka’) and four different N regimes (N0: No N as the control, N1: Urea, N2: Nitrate N, N3: Ammonium N and N4: a 1:1 mixture of nitrate N and ammonium N). The rate of N applied was 500 mg N·kg soil–1 in each case. It was found that total N content, root nitrate reductase (NR) activity, glutamine synthetase (GS) activity and shoot glutamate synthase (GOGAT) activity of B. dactyloides were significantly improved by adding mixed N (P<0.05). Shoot nitrate N content of B. dactyloides was significantly improved by adding nitrate N (P<0.05). Root nitrate N and ammonium N contents of B. dactyloides were significantly improved by adding urea (P<0.05). The shoot ammonium N content and NR activity of B. dactyloides were significantly improved by adding ammonium N (P<0.05). Shoot GS activity of B. dactyloides was significantly reduced by adding ammonium N (P<0.05). Root GOGAT activity of B. dactyloides was significantly reduced by adding nitrate N (P<0.05). Mixed N can better improve the physiological activity and promote the growth of B. dactyloides, but single nitrogen source will inhibit some nitrogen assimilase activity. Based on these results, it is recommended that 1:1 mixed nitrogen should be used as the nitrogen source in the production of B. dactyloides. Where the ammonium:nitrate is not 1:1, urea should be used as the nitrogen source. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.