好氧亚硝化颗粒污泥中硝化细菌群落结构分析

在小试好氧上流式污泥床(AUSB)反应器中,实现了由厌氧颗粒污泥到好氧硝化污泥再到亚硝化颗粒污泥的转化,AUSB反应器的亚硝化率稳定在90%以上.利用FISH、荧光实时定量PCR等技术,考察了AUSB反应器中好氧颗粒污泥中硝化菌群的生态分布.结果表明:好氧亚硝化颗粒污泥呈层状结构,氨氧化细菌(AOB)主要分布在颗粒污泥表层,亚硝酸盐氧化细菌(NOB)多分布在内层,颗粒内核则无活性细胞;随反应器氨氮负荷逐渐提高,颗粒污泥中AOB的相对含量逐渐升高,当NH₃-N负荷分别为0、0.4、1、     

钙离子和钙激活酶外源抑制剂对牛肉钙激活活性和超微结构的影响

3头改良黄牛(鲁西黄牛×犁木赞)在屠宰厂按照标准的屠宰工艺屠宰并预冷20 h后取样,样品分7组,按样品重10%分别注射蒸馏水(对照)、200 mmol*L1 CaCl2、200 mmol*L1 EGTA、200 mmol*L1 ZnCl2、0.2 mg*mL1亮抑蛋白酶肽、0.2 mg*mL1亮抑蛋白酶肽+0.01 mg*mL1 Triton X-100、0.01 mg*mL1 Triton X-100 7个不同处理,将样品分别成熟3、8和16 d后测μ钙激活酶(μ-calpain)和m钙激活酶(m-calpain)的活性并观察肌纤维超微结构.实验结果发现,与注射CaCl2的牛肉相比,注射外源性钙激活酶抑制剂(亮抑蛋白酶肽、ZnCl2)牛肉的μ钙激活酶保持活性时间延长,超微结构变化受到抑制.提示,钙激活酶特别是μ钙激活酶很可能参与了牛肉嫩化过程并发挥着关键作用.     

潮汐流-水平潜流组合人工湿地的污水处理效果

利用室内潮汐流和水平潜流人工湿地装置,构建潮汐流-水平潜流(TF-HF)和水平潜流-潮汐流(HF-TF)2种不同组合的人工湿地系统,探讨不同组合方式的水平潜流和潮汐流人工湿地复合系统对污染物的去除效果。研究结果表明:在进水条件相同、潮汐流人工湿地淹没排空比均为12h∶12h、水平潜流人工湿地水力停留时间(HRT)均为4d、系统回流比均为1∶1条件下,潮汐流-水平潜流人工湿地系统和水平潜流-潮汐流人工湿地系统对总有机碳(TOC)的去除率分别为90.2%和91.3%,无明显差异;对NH4+-N的平均去除率分别为19.5%和39.2%,总氮(TN)的平均去除率分别为10.3%和30.5%,水平潜流-潮汐流人工湿地系统表现出较好的运行效果。     

Hydrolytic Enzyme Inhibitors and Necrotic Reactions in Potato Leaves Reduce Reproductive Success of Colorado Potato Beetle

In field and laboratory conditions the reproductive potential （survival at different stages of development） of the Colorado potato beetle has been measured, the dependence of the parameters of insects fertility on varietal features of the feed has been investigated, the food activity of the representatives of insects from four areas of the Southern Urals has been measured, the intensity and time of hypersensitivity reactions on potato leaves has been defined. In laboratory experiments, the level of activity of hydrolytic enzymes in insects and the level of activity of these enzymes inhibitors in the leaves of three potato varieties differing in their resistance to the Colorado potato beetle have been determined. The results show that the insects-representatives of different samples have different food activity in relation to different potato varieties. High mortality rates were revealed at feeding with leaves of potato of the Bashkir variety characterized by a high level of hydrolases inhibitors and relatively rapid development of necrotic reactions after the appearance of eggs laying on the leaves. We suppose that the neerogenetic barrier appearing in the form of necrosis is the major cause of the fetal mortality of insects. The level of the content of inhibitors inactivating larvae digestive enzymes affects the survival of insects at postembryonic stages. The speed of the necrosis emergence, the level of activity of digestive enzymes inhibitors in potato can be considered as criteria for the selection of breeding material for resistance to the Colorado potato beetle.     

氮肥品种和含水量对水稻土N2O排放速率及排放过程的影响

稻田是全球重要的N_2O排放源,氮肥有效性和水分状况是影响稻田N_2O排放的关键因素。为探明水稻土在施用尿素和硫酸铵时,水分变化对短时间内N_2O总排放速率及不同硝化过程(自养硝化、异养硝化、非生物作用)贡献的影响,通过室内培养实验,采用乙炔抑制法,测定了不同时间段N_2O释放量,并计算释放速率。结果表明:施用氮肥可以显著提高自养硝化、异养硝化及总过程的N_2O排放速率,并且施尿素处理N_2O排放速率大于施硫酸铵。随着土壤水分含量由48%增加至160%,总N_2O排放速率以及自养硝化、异养硝化N_2O排放速率显著增加。供试水稻土N_2O的产生主要是由生物过程主导的,其中硝化作用(包括自养硝化、异养硝化)最高贡献达51.1%,非生物作用贡献所占比重很小。这些结果可为科学施肥,降低农田土壤N_2O排放提供科学依据。     

不同氨氮浓度对部分亚硝化过程中N_2O释放的影响

[目的]研究氨氮浓度对部分亚硝化过程中温室气体N2O释放的影响。[方法]利用序批式生物膜反应器(SBBR),采用间歇曝气的方式,分析进水不同氨氮浓度对部分亚硝化过程中N2O产生的影响。[结果]当进水氨氮浓度不同时,部分亚硝化过程中DO、ORP变化趋势大体一致,出水中亚硝氮与氨氮的浓度比都能达到1∶1,而且硝氮始终都维持在较低水平。进水氨氮浓度对部分亚硝化过程中N2O的释放有显著影响,氨氮浓度越高,N2O的释放量越大。其中,当氨氮浓度为400 mg/L时,N2O的释放量高达37 mg左右。[结论]部分亚硝化过程中N2O的释放可能与NH4+、NO2-的浓度有关。     

不同热处理对黑豆干物质消化率,蛋白质消化率的影响

为了研究热处理的温度和时间对黑豆干物质消化率(DMD)、蛋白质消化率(PD)及脲酶活性的影响规律,对经过110℃和121℃下分别处理3,9和15min的饲用黑豆进行了离体干物质消化率和离体蛋白质消化率及脲酶活性的测定。结果表明:在121℃处理15min的样本干物质消化率和蛋白质消化率最高,分别为75.13%,90.91%,脲酶活性最低,为0.04mg/min·g。作者认为:在本研究范围内,湿热处理最适宜的温度是121℃,时间是15min。     

Degradation and effect of hydrogen peroxide in small‐scale recirculation aquaculture system biofilters

From an environmental point of view, hydrogen peroxide (HP) has beneficial attributes compared with other disinfectants in terms of its ready degradation and neutral by‐products. The rapid degradation of HP can, however, cause difficulties with regard to safe and efficient water treatment when applied in different systems. In this study, we investigated the degradation kinetics of HP in biofilters from water recirculating aquaculture systems (RAS). The potential effect of HP on the nitrification process in the biofilters was also examined. Biofilter elements from two different pilot‐scale RAS were exposed to various HP treatments in batch experiments, and the HP concentration was found to follow an exponential decay. The biofilter ammonia and nitrite oxidation processes showed quick recuperation after exposure to a single dose of HP up to 30 mg L^?1. An average HP concentration of 10–13 mg L^?1 maintained over 3 h had a moderate inhibitory effect on the biofilter elements from one of the RAS with relatively high organic loading, while the nitrification was severely inhibited in the pilot‐scale biofilters from the other RAS with a relatively low organic loading. A pilot‐scale RAS, equipped with two biofilter units, both a moving‐bed (Biomedia) and a fixed‐bed (BIO‐BLOK^®) biofilter, was subjected to an average HP concentration of ～12 mg L^?1 for 3 h. The ammonium‐ and nitrite‐degrading efficiencies of both the Biomedia and the BIO‐BLOK^® filters were drastically reduced. The filters had not reverted to pre‐HP exposure efficiency after 24 h, suggesting a possible long‐term impact on the biofilters.     

水稻抽穗后喷施多胺合成抑制剂对水稻籽粒多胺含量与组成的影响

以高多胺水稻品种金陵香糯为材料,在抽穗期、开花期和灌浆期用不同浓度的多胺合成抑制剂D 精氨酸（D Arg）、甲基乙二醛双（鸟苷腙）（MGBG）和环己胺（CHA）喷施穗部和剑叶,研究它们对水稻籽粒中游离态和结合态多胺含量和组成的影响。结果表明,D Arg对3个时期水稻籽粒中游离态和结合态各多胺含量及总量均有显著抑制作用,其中开花期和灌浆期处理的效果较明显。MGBG和CHA主要影响籽粒多胺的组成,对多胺总量的影响仅MGBG在开花期、CHA在抽穗期和开花期处理的抑制作用达显著水平。     

改性尿素硝酸铵溶液调控氮素挥发和淋溶的研究

为了提高肥料的利用率,以尿素硝酸铵溶液为原料、聚氨酸为保护剂,复合抑制剂NBPT(N-丁基硫代磷酰三胺)和DMPP(3,4-二甲基吡唑磷酸盐)为材料,开发出改性尿素硝酸铵溶液(YUL1和YUL2),研究其对华北平原夏玉米追肥过程中的氨挥发和淋溶损失的调控效果。田间试验设置6个处理:不施氮肥(CK)、农民习惯追施尿素(CN)、优化追施尿素(CNU)、优化追施尿素硝酸铵溶液(UAN)、优化追施改性尿素硝酸铵溶液(YUL1)和优化追施改性尿素硝酸铵溶液(YUL2)。采用扫描电镜和能谱仪分析相关指标变化,在夏玉米喇叭口期追施氮肥后15d内进行田间原位连续动态观测氨挥发和土壤铵态氮和硝态氮变化,并在玉米成熟期测定产量,计算经济效益。结果表明,改性尿素硝酸铵溶液清澈无杂质,流延后成膜表面光滑、致密,抑制剂在膜表面分布均匀;能谱测试膜层表面磷硫含量增高,证明复合抑制剂与尿素硝酸铵溶液达到有效融合。在同等优化施氮量下:与CNU相比, YUL1氨挥发总量显著降低19.3%, YUL2增加9.6%;与UAN相比, YUL1、YUL2分别显著降低57.3%和42.0%。与其他施氮处理相比, YUL1和YUL2夏玉米季生长中后期0～20 cm土层依然保持相对较高的氮素含量水平,夏玉米收获后土壤硝态氮含量分别比CNU高46.0%和43.4%,比UAN高45.6%和44.7%;180～200cm土层硝态氮含量显著低于其他处理。在保证产量和净收益的同时,改性尿素硝酸铵肥料显著降低了氮素的氨挥发和淋溶损失浓度,尿酶抑制剂含量相对较高的YUL1抑制氨挥发的效果更好,硝化抑制剂含量相对高的YUL2硝态氮向下淋失的风险更小。