小白菜幼苗对二氧化氮胁迫的应答及过氧化氢的调节

【目的】研究小白菜幼苗对二氧化氮(NO2)急性胁迫的应答及过氧化氢(H2O2)的调节作用。【方法】在自制的熏气箱中对供试植株进行NO2(浓度分别为0.25、0.5、1.0和2.0μl·L-1)熏蒸24h(10﹕00～次日10﹕00),测定某些生理生化指标。延长熏气至7d,每天7h(8﹕00～15﹕00),测定植株的生长速率。为了评价外源H2O2在植株对NO2应答中可能的调节作用,熏气前1d对试验组叶面喷洒10mmol·L-1H2O2溶液(相当于每棵植株喷洒约1mgH2O2),对照组喷洒等量蒸馏水。【结果】0.25μl·L-1NO2促进小白菜生长,而0.5μl·L-1及以上浓度NO2使植株生长速率和叶绿素含量显著降低,叶片硝酸还原酶(NR)和超氧化物歧化酶(SOD)活性以及丙二醛(MDA)含量增加;1μl·L-1及以上浓度NO2使老叶片出现坏死,绿色部分的过氧化氢酶(CAT)活性和硝酸盐(NO3-)含量增加,抗坏血酸(ASA)含量和光合速率下降,但气孔导度不受影响。10mmol·L-1H2O2预处理显著减轻NO2对植株的不利影响,其中生长速率、ASA和MDA含量等与只通入碳滤空气的对照水平相当,光合速率明显恢复,但NO3-含量和NR活性没有变化,SOD和CAT活性被进一步诱导,气孔导度降低。【结论】NO2急性胁迫引发了小白菜幼苗氧化胁迫伤害;H2O2预处理提高了小白菜的抗氧化能力,增强了对高浓度NO2的耐受性;NO2熏蒸使小白菜叶片NO3-含量增加。

新型吡唑类化合物DL-1的硝化抑制效应初探

以国内外应用较为广泛的硝化抑制剂双氰胺(DCD)为参比对象,采用室内培养方法,对新型吡唑类化合物DL-1的硝化抑制效应进行初步探讨.结果表明,DL-1对土壤中铵的氧化过程具有显著的抑制效应,前3周的硝化抑制率可达70%以上,且硝化抑制能力在第14天至28天最强.与等量DCD相比,施用量为(NH4)2SO4氮量1.0%的DL-1在14、21和28d使土壤中的NO3--N含量分别下降26.23%、33.27%和23.31%;与不加抑制剂的对照处理相比,土壤NO3--N含量则分别下降了71.12%、69.10%和55.14%.当DL-1用量为(NH4)2SO4氮量的2.0%时,土壤的硝化作用受到了更强烈的抑制,到培养第90天试验结束,土壤中的NO3--N含量始终维持在较低水平.

新型脲酶抑制剂LNS与双氰胺配合施用对菜田土壤尿素氮转化及蔬菜生长的影响

采用微区试验方法,初步探讨了新型脲酶抑制剂LNS及其与硝化抑制剂双氰胺(DCD)配合施用对菜田土壤尿素氮转化和蔬菜生长的影响。结果表明,LNS对土壤脲酶活性可以起到一定的抑制作用,从而延迟尿素N在土壤中的水解和NH4+-N的释放高峰期,其发挥作用的时间大约在施用后前10天。LNS与DCD配合施用则能显著抑制尿素水解后NH4+的氧化作用,使蔬菜整个生长期内的NO3--N含量维持在较低水平。抑制剂的施用对芹菜产量虽然没有产生显著影响,但可以降低其体内硝酸盐含量,并提高芹菜干物质含量。

畜禽粪便堆肥过程中各种氮化合物的动态变化及腐熟度评价指标

对不同畜禽粪便在堆肥过程中各种含氮化合物的动态变化进行了研究,结合综合性腐熟度评价指标——种子发芽指数(GI),探讨了畜禽粪便堆肥过程中与氮有关的腐熟度评价指标.结果表明:随着堆肥的进行,除奶牛粪外,其它畜禽粪便的全氮(TN)含量均呈先下降而后平稳变化趋势,奶牛粪则呈先增加而后平稳变化趋势;各种畜禽粪便中,碱解性氮(HN)含量先增后降;NH4+-N含量先下降而后保持平稳;NO3--N含量则持续增加;NH4+-N/NO3--N迅速降低.堆肥腐熟度指标中,除综合性评价指标GI值外,HN/TN和NH4+-N/TN也可作为评价畜禽粪便腐熟程度的优选指标,而NO3--N/TN只能作为一般性评价指标.根据综合性评价指标GI值达到腐熟要求的标准(GI>0.50),除仔猪粪外,其它畜禽粪便在HN/TN<20.77%、NH4+-N/TN<10.06%及NO3--N/TN>0.38%时基本达到腐熟要求.

抑制剂对尿素转化及土壤中氮的影响研究

以草甸棕壤为基质进行室内培养试验结果表明,脲酶抑制剂与硝化抑制剂配合使用,明显地抑制了NH4+-N向NO3--N的转化。NBPT+DCD处理效果最好,可延缓硝态氮的释放高峰达40天以上;H1和HA都表现出较强的硝化抑制作用。H3和H2对硝态氮基本无影响。

影响土壤N_2O排放和CH_4吸收的主控因素的研究(英文)

本文于2000年7月,在实验室模拟条件下,以长白山阔叶红松林鲜土壤为对象,采用正交试验设计法对土壤进行培养实验,研究了影响土壤N2O排放和CH4吸收的主要因素。考察了温度、水分、pH值、NH4+及NO3-五因素对森林土壤N2O排放和CH4吸收的影响。实验结果显示:在本试验设计的因素、水平条件下,N2O排放速率、CH4吸收速率二者均与土壤pH值和温度这两个因素呈显著正相关。并且N2O排放速率与CH4吸收速率间呈显著线性正相关关。

与氮转化有关的土壤酶活性对抑制剂施用的响应

利用室内模拟培养试验 ,研究好气条件下施用尿素后土壤脲酶、硝酸还原酶、亚硝酸还原酶和羟胺还原酶活性对脲酶抑制剂氢醌 (HQ)与硝化抑制剂包被碳化钙 (ECC)和双氰胺 (DCD)组合 (HQ +ECC、HQ +DCD)的响应 .结果表明 ,HQ +DCD组合与其它抑制剂处理相比能更有效地降低土壤脲酶活性 ,增加硝酸还原酶、亚硝酸还原酶、羟胺还原酶活性 .不同处理土壤脲酶、亚硝酸还原酶和羟胺还原酶活性与土壤NH4 + 、NO3-、NH3 挥发和N2 O排放速率间存在不同形式的显著相关关系 .土壤脲酶、亚硝酸还原酶和羟胺还原酶活性之间亦存在不同形式的显著正相关关系 .

新型二维异核配位聚合物{[NdBi(cydta)(NO_3)_2(H_2O)_4]·2.5H_2O}_n的晶体结构与热分解

由Bi(Hcydta).5H2O和Nd(NO3).6H2O按1︰1的物质的量比,在水溶液中合成了含Bi(III)-Nd(III)的异核配位聚合物{[(NO3)Nd(H2O)4(μ3-cydta)Bi(μ-ONO2)].2.5H2O}n.用元素分析、红外光谱、热重-差热和X射线单晶衍射等手段对标题配合物的组成和结构进行了表征.该配合物属三斜晶系,空间群P1,晶胞参数:a=0.9235(3)nm,b=1.0902(4)nm,c=1.4253(5)nm,α=71.840(4)°,β=86.877(4)°,γ=76.991(4)°,Z=2,Mr=936.65,V=1.3284(8)nm3,Dc=2.342g.cm-3,μ=8.646mm-1,F(000)=900,最终偏离因子R1=0.0406,wR2=0.1124.在该配合物中,铋(III)与配体cydta4-的4O2N和1个硝酸根中1个O原子以及邻位分子的硝酸根形成8配位的畸变双帽三棱柱.钕(III)与4个水分子的O,1个硝酸根中2个O以及来自3个不同配体cydta4-的桥联羧基O结合,形成9配位的三帽三棱柱构型.羧酸根在Bi—Nd和硝酸根在Bi—Bi间的桥联作用...

Sonochemical synthesis of monodispersed KY3F10 : Eu3+ nanospheres with bimodal size distribution

Monodispersed KY3F10:Eu3+ nanospheres with bimodal size distribution have been successfully synthesized via a facile and efficient sonochemical method in a surfactant-free system. Rare-earth nitrate (Y, Eu)(NO3)(3) and potassium fluoborate (KBF4) were used as precursors. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and photoluminescence (PL) spectra were used to characterize the samples.

Facile synthesis and luminescence properties of octahedral YVO4:Eu3+ microcrystals

Uniform octahedral YVO4:Eu3+ microcrystals have been successfully prepared through a designed two-step hydrothermal conversion method. One-dimensional precursor Y4O(OH)(9)NO3 was first prepared through a simple hydrothermal process without using any surfactant, catalyst or template. Subsequently, well-defined octahedral YVO4 was synthesized at the expense of the precursor during a hydrothermal conversion process. XRD results demonstrate that the diffraction peaks of the final product can be well indexed to the pure tetragonal phase of YVO4.

Solvent impregnated resin prepared using task-specific ionic liquids for rare earth separation

A novel bifunctional task-specific ionic liquid (TSIL), i.e. [trialkylmethylammonium][sec-nonylphenoxy acetate] ([A336] [CA-100]) was impregnated on intermediate polarized XAD-7 resin, and the prepared solvent impreganated resin (SIR) was studied for rare earth (RE) separation. Adsorption ability of the SIR was indicated to be obviously higher than that prepared by [A336][NO3] because of the functional anion of [A336][CA-100]. Adsorption kinetics, adsorption isotherm, separation and desorption of the SIR were also studied.

Poly[[diaqua-mu-4,4 '-bipyridine-dinitratodi-mu-L-tyrosinato-dicopper(II)]: a chiral two-dimensional coordination polymer

The title compound, [Cu-2(C9H10NO3)(2)(NO3)(2)(C10H8N2)-(H2O)(2)](n), contains Cu-II atoms and L-tyrosinate (L-tyr) and 4,4'-bipyridine (4,4'-bipy) ligands in a 2:2:1 ratio. Each Cu atom is coordinated by one amino N atom and two carboxylate O atoms from two L-tyr ligands, one N atom from a 4,4'-bipy ligand, a monodentate nitrate ion and a water molecule in an elongated octahedral geometry. Adjacent Cu atoms are bridged by the bidentate carboxylate groups into a chain. These chains are further linked by the bridging 4,4'-bipy ligands, forming an undulated chiral two-dimensional sheet. O-H center dot center dot center dot O and N-H center dot center dot center dot O hydrogen bonds connect the sheets in the [100] direction. This study offers useful information for the engineering of chiral coordination polymers with amino acids and 4,4'-bipy ligands by considering the ratios of the metal ion and organic components.

Carbon dioxide/propylene oxide coupling reaction catalyzed by chromium salen complexes

A series of chromium/Schiff base complexes N,N'-bis(salicylidene)-1,2-phenylenediamino chromium(III) X were prepared and employed for the alternating copolymerization of carbon dioxide with racemic propylene oxide in the presence of (4-dimethylamino)pyridine. The effect of the complex structure and reaction conditions on the catalytic activity, the poly(propylene carbonate)/cyclic carbonate (PPC/PC) selectivity, and the polymer head-to-tail linkages was examined. The experiments indicated that N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-phenylenediamino chromium(III) (NO3) exhibited the highest PPC/PC selectivity as well as polymer head-to-tail linkages and N,N'-bis(3,5-dichlorosalicylidene)-1,2-phenylenediimino chromiu(III) (NO3) possessed the highest catalytic activity among these chromium/Schiff base complexes. The structure of the produced copolymer was characterized by the IR, H-1 NMR, and C-13 NMR measurements.

Spindle-like Lanthanide Orthovanadate Nanoparticles: Facile Synthesis by Ultrasonic Irradiation, Characterization, and Luminescent Properties

A general and facile ultrasonic irradiation method has been established for the synthesis of the lanthanide orthovanadate LnVO(4) (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) nanoparticles from an aqueous solution of Ln(NO3)(3) and NH4VO3 without any surfactant or template. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and photoluminescence (PL) spectra as well as kinetic decays were employed to characterize the as-prepared products. Ultrasonic irradiation has a strong effect on the morphology of the LnVO(4) nanoparticles. The SEM and TEEM images illustrate that the as-formed LnVO(4) particles have a spindle-like shape with an equatorial diameter of 30-70 nm and a length of 100-200 am, which are the aggregates of even.

Alternating copolymerization of carbon dioxide and propylene oxide by single-component cobalt salen complexes with various axial group

A series of single-component cobalt salen complexes, N,N'-bis(salicylidene)-1,2phenylenediamino cobaltIII X(X = Cl (1a), Br (1b), NO3 (1c), CF3COO (1d), BF4 (le), and N3 (If)) (SalphCoX), were prepared for alternating copolymerization of carbon dioxide and propylene oxide(PO) under mild condition. The axial anion X group of the SalenphCoX played important role in tailoring the catalytic activity, polymeric/cyclic carbonate selectivity, as well as stereochemistry of carbonate unit sequence in the polymer chain. SalenphCoX with an electron-withdrawing axial X group (complex 1c) was an ideal catalyst for the copolymerization of CO2 and PO to selectively produce polycarbonate with similar to 99% carbonate linkage and over 81% head-to-tail structure.