Ni(NO3)2对汕优13水稻幼苗中过氧化氢酶活性的影响

在水稻幼苗2.5叶期，分别用浓度W/V0.01%,0.03%和0.04%(Ni(NO3)2溶液（含0.05%Tween20聚环氧乙烷山梨糖醇单月桂酸酯）喷雾处理，以0.5%(W/V)Tween20作对照，在4小时，24小时，48小时，72小时，96小时分别测定叶片中的过氧化氢酶（CAT）活性，结果表明，Ni(NO3)2对过氧化氢酶活性有抑制作用且随其浓度的升高，抑制作用越明显，在72小时抑制作用最强，过氧化氢酶活性比对照分析下降了21.7%,28.3%,55.8%。     

Pentaborate Polyanion in the Crystal Structure of Ulexite, NaCaB5O6(OH)6{middle dot}5H2O

Triclinic ulexite crystals contain isolated borate polyanions [B(5)O(6)(OH)(6)](3-) related to the well known pentaborate polyanion [B(5)O(6)(OH)(4)](-) by addition of two hydroxyl groups to two opposite B-O triangles. The isolated ulexite polyanions form the [B(5)O(7)(OH)(4)](n)(3n-) chains previously found in crystals of the related mineral probertite, NaCaB(5)O(7)(OH)(4).3H(2)O.     

光照对分蘖期水稻叶际及根系-培养液体系 N2O 和 NOX（NO，NO2）排放的影响

[目的]该研究探讨光照对分蘖期水稻根、叶界面N2O和NOX排放的作用及其机制。[方法]试验在水培控氮、小型光控培养箱控光和同步测定条件下,探讨了不同光质、光强及光控处理对分蘖期水稻叶际及根系-培养液体系 N2O和 NOX 排放的影响。[结果]①在相同氮源(NH4NO3-N,90 mg/L)、日间光照为6000、8000 lx条件下,分蘖期平均水稻叶际 N2O和NO排放速率分别为27.08、32.33μg/(pot·h)和0.114、0.057μg/(pot·h),分别占 N2O和 NO总排放的57.38%、58.65%和9.65%、4.52%,水稻叶际是N2O的重要排放源;②在光强(1600 lx)一致条件下,LED黄、绿、白、红、蓝光处理的平均水稻叶际N2O 排放速率分别为6.83、9.40、9.73、2.82和4.08μg/(pot·h),光 X强较高的红(3000 lx)、蓝光(2500 lx)处理能同步抑制分蘖期水稻根、叶界面N2O的挥发(P<0.01),LED红、白光有促进日间水稻叶际NO排放的作用,LED蓝光则有同步抑制水稻根、叶界面 NO挥发的作用效果,但不同光控处理下水稻根、叶界面均无明显的NO2净排放作用;③0~8000 lx 范围内随着光照增强,水稻根部NO及根、叶界面 N2O排放同步增加,但高光强(6000~8000 lx)下水稻叶际 NO排放显著大幅下降(P<0.01)。[结论]水稻根、叶界面均以N2O挥发为主;试验供氮水平下适度控制日间光强并同步增加红光、蓝光比例的技术,能同步抑制水稻根、叶界面氮氧化物的排放。     

烤烟套种甘薯对烟草氮磷钾营养的影响

通过田间小区试验,研究了烤烟与甘薯套种对烟草氮磷钾素营养的影响.结果表明:烤烟套种甘薯与烤烟单作相比,甘薯吸收了土壤中过多残留的营养元素,土壤营养元素更趋于平衡;增加了土壤耕层中植株的根系,其周围营养元素有效性得以提高,相对含量增加,烟株与环境友好发展,烟株养分得以改善;对烤烟的茎粗、叶厚、株高、叶长、叶宽、有效叶片数等生物学性状未产生不良影响.     

马铃薯施用Mg·N·P_2O_5·K_2O肥优化数学模型研究

采用二次回归正交旋转组合设计方法研究Mg、N、P2O5、K2O施用量与马铃薯生产成本、纯收入及产投比的关系,建立了马铃薯生产成本、纯收入及产投比与Mg、N、P2O5、K2O施用量间的优化数学模型。在对模型进行深入分析的基础上,作了计算机模拟试验,提出了2套马铃薯高产、高效栽培的施肥模型:纯收入高于9 000元/hm2,产投比高于2.21时的施肥量为Mg肥(MgSO2)15.697 5～18.742 5kg/hm2,N肥(纯N)35.100 0～45.137 5 kg/hm2,磷肥(P2O5)97.47～155.52 kg/hm2,K肥(K2O)125.685～149.445 kg/hm2。纯收入高于10 000元/hm2,产投比高于3.0施肥量为Mg肥(MgSO2)16.485～27.765 kg/hm2,N肥(纯N)9.552 5～44.697 5 kg/hm2,磷肥(P2O5)63.585～129.915kg/hm2,K肥(K2O)为102.802 5～173.947 5 kg/hm2。     

土壤pH影响氧化亚氮(N2O)排放的研究进展

氧化亚氮(N_2O)是第三大温室气体,也是21世纪内平流层臭氧(O_3)的首要分解者。在过去约150年间,大气中N_2O的浓度持续增加,其主要原因在于化肥和有机肥料刺激下土壤中N_2O的大量排放。因此,理解土壤中N_2O的排放机制与影响因素,已经成为估算N_2O排放清单和制定N_2O减排政策的关键科学问题。土壤pH是影响N_2O排放的重要环境因子之一,但目前对其相对重要性和影响机制尚不明确。该文基于已有文献的梳理,总结了原位观测和室内培养研究中土壤pH与N_2O排放之间的统计结果,发现多数研究中N_2O排放与土壤pH呈显著负相关关系;并且从生物硝化、生物反硝化和非生物过程3个方面探讨了土壤pH影响N_2O排放的微观机制。在此基础上,本文对今后的研究工作提出展望,以期为后续的研究提供参考和依据。     

Ordering of V2+, Mn2+, and Fe3+ Ions in Zoisite, Ca2Al3Si3O12(OH)

The presence of very small amounts of Mn(2+), V(2+), and Fe(3+) ions in zoisite can be easily detected by the electron paramagnetic resonance technique at room temperature. The Mn(2+) and Fe(3+) ions are completely ordered and are probably located in the Ca(1)- and Al(II)-sites, respectively, whereas the V(2+) ions probably occupy both Ca(1)- and Ca(2)-sites, with a preference for the Ca(1)-site.     

室内模拟有机肥中NO_3~-、NO_2~-的淋失规律及其对土壤环境的影响

采用室内土柱模拟淋溶方法研究施用有机肥后土壤中硝态氮和亚硝态氮的淋溶规律。测定了淋溶液中硝态氮、亚硝态氮以及土柱不同层次土壤中硝态氮和亚硝态氮的含量。结果表明:有机肥处理中硝态氮的量明显高于复合肥处理,且随施肥量的增加影响愈严重,最大淋溶量在时间上表现出滞后;亚硝态氮淋溶速度快,有机肥处理的亚硝态氮低于复合肥处理的,随施肥水平的增加,亚硝态氮以极小的斜率呈直线方式上升,当有机肥施用水平超过某一临界值时,对土壤有潜在污染。     

Effects of 1-Methylcyclopropene on NO Content, NOS Activity, and H2O2 Content in Postharvest Suli Pears

Studies were conducted over the effects of 1-methylcycolpropene (1-MCP) treatment on postharvest life of Suli pears (Pyrus bretschneideri Rehd.) stored at room and cold temperatures on nitric oxide (NO), nitric oxide synthase (NOS)activity, and hydrogen dioxide (H2O2). Results showed that the 1-MCP treatment had little effect on total soluble solids (TSS) at both room and cold temperatures. 1-MCP delayed softening of Suli pear fruits, decreased respiratory rate and H2O2 accumulation, and increased NO and NOS activity at room temperature storage, while the effect of cold temperature storage was relatively inferior. There was a significant positive correlation between NOS activity and NO content. It is concluded that 1-MCP had effects on endogenous NO content and accumulation of H2O2. Similarly, H2O2 acting as a signaling molecule via regulating NO level affects the ripening and senescence of Suli pears.     

Ce-Zr-La-Co复合氧化物与LaCoO_3/Ce_(0.6)Zr_(0.4)O_2的催化性能与结构分析

采用柠檬酸法制备了Ce-Zr-La-Co复合氧化物催化剂和LaCoO3/Ce0.6Zr0.4O2负载型催化剂,并用热重法测试了2种催化剂对碳烟的催化活性,催化剂LaCoO3/Ce0.6Zr0.4O2显示了更高的活性,碳烟的起燃温度是542℃,低于Ce-Zr-La-Co复合氧化物催化剂的552℃,比纯碳烟的起燃温度低97℃.采用程序升温还原法(Hydrogen Temperature-programmed Reduction,H2-TPR)、N2吸附BET、X-射线衍射仪(X-ray Diffraction,XRD)、傅立叶红外仪(Fourier Transform Infrared Spectroscopy,FTIR)和X-射线光电子能谱仪(X-ray Photoelectron Spectroscopy,XPS)等技术对催化剂进行了表征.结果表明,XRD显示负载型氧化物LaCoO3/Ce0.6 Zr0.4 O2形成了完好的钙钛矿结构相,而Ce-Zr-La-Co复合氧化物则形成了铈锆固溶体为主以及少量的钙钛矿和Co3O4氧化物相;XPS结果显示LaCoO3/Ce0.6Zr0.4O2催化剂表面弱吸附氧Oˉ的含量...     

Dianion Stabilization by (M(C5(CH3)5)2)+: Theoretical Evidence for a Localized Ring in (DDQ)2-

Organic dianions have been stabilized by (M(C(5)(CH(3))(5))(2))(+), where M is iron or cobalt. This has allowed the structural and spectroscopic characterization of these dianions. The structure of (M(C(5)(CH(3))(5))(2))(2)(+) (DDQ)(2-), where DDQ is 2,3-dichloro-5,6-dicyanobenzoquinone, has been determined by x-ray crystallography. The structure of (DDQ)(2-)is consistent with ab initio molecular orbital calculations that suggest a localizd as opposed to a delocalized (aromatic) ring structure.     

光照对分蘖期水稻叶际及根系-培养液体系N_2O和NO_X(NO,NO_2)排放的影响(英文)

[目的]该研究探讨光照对分蘖期水稻根、叶界面N_2O和NO_X排放的作用及其机制。[方法]试验在水培控氮、小型光控培养箱控光和同步测定条件下,探讨了不同光质、光强及光控处理对分蘖期水稻叶际及根系-培养液体系N_2O和NO_X排放的影响。[结果](1)在相同氮源(NH4NO3-N,90 mg/L)、日间光照为6 000、8 000lx条件下,分蘖期平均水稻叶际N_2O和NO排放速率分别为27.08、32.33μg/(pot·h)和0.114、0.057μg/(pot·h),分别占N_2O和NO总排放的57.38%、58.65%和9.65%、4.52%,水稻叶际是N_2O的重要排放源;(2)在光强(1 600 lx)一致条件下,LED黄、绿、白、红、蓝光处理的平均水稻叶际N_2O排放速率分别为6.83、9.40、9.73、2.82和4.08μg/(pot·h),光X强较高的红(3 000 lx)、蓝光(2 500 lx)处理能同步抑制分蘖期水稻根、叶界面N_2O的挥发(P<0.01),LED红、白光有促进日间水稻叶际NO排放的作用,LED蓝光则有同步抑制水稻根、叶界面NO挥发的作用效果,但不同光控处理下水稻根、叶界面均无明显的NO2净排放作用;(3)0～8 000 lx范围内随着光照增强,水稻根部NO及根、叶界面N_2O排放同步增加,但高光强(6 000～8 000 lx)下水稻叶际NO排放显著大幅下降(P<0.01)。[结论]水稻根、叶界面均以N_2O挥发为主;试验供氮水平下适度控制日间光强并同步增加红光、蓝光比例的技术,能同步抑制水稻根、叶界面氮氧化物的排放。     

Universality classes for domain wall motion in the ferromagnetic semiconductor (Ga,Mn)As

Magnetic domain wall motion induced by magnetic fields and spin-polarized electrical currents is experimentally well established. A full understanding of the underlying mechanisms, however, remains elusive. For the ferromagnetic semiconductor (Ga,Mn)As, we have measured and compared such motions in the thermally activated subthreshold, or "creep," regime, where the velocity obeys an Arrhenius scaling law. Within this law, the clearly different exponents of the current and field reflect different universality classes, showing that the drive mechanisms are fundamentally different.     

Long-range incommensurate charge fluctuations in (Y,Nd)Ba2Cu3O(6+x)

The concept that superconductivity competes with other orders in cuprate superconductors has become increasingly apparent, but obtaining direct evidence with bulk-sensitive probes is challenging. We have used resonant soft x-ray scattering to identify two-dimensional charge fluctuations with an incommensurate periodicity of ~3.2 lattice units in the copper-oxide planes of the superconductors (Y,Nd)Ba(2)Cu(3)O(6+)(x), with hole concentrations of 0.09 to 0.13 per planar Cu ion. The intensity and correlation length of the fluctuation signal increase strongly upon cooling down to the superconducting transition temperature (T(c)); further cooling below T(c) abruptly reverses the divergence of the charge correlations. In combination with earlier observations of a large gap in the spin excitation spectrum, these data indicate an incipient charge density wave instability that competes with superconductivity.     

氮磷钾肥对茎瘤芥产量和硝酸盐的影响

采用田间试验和化验分析的方法,研究了不同氮、磷、钾施用水平下,茎瘤芥各器官产量和硝酸盐含量变化特征.结果表明,瘤茎产量与氮、磷、钾施用量均呈极显著二次回归关系;瘤茎硝酸盐含量与施氮量呈极显著正相关,施磷量(P2O5)在55.8 kg/hm2、施钾量(K2O)在133.5 kg/hm2范围内,增施磷、钾肥可提高瘤茎产量而降低硝酸盐含量.茎瘤芥无公害生产上,应控制氮、磷用量,适当增施钾肥.     

乳清蛋白抗氧化肽对H_2O_2所致人胚肺成纤维细胞MRC-5过氧化损伤的保护作用

【目的】探讨纯化后的乳清蛋白抗氧化肽P4对人胚肺成纤维细胞(human lung fibroblast)MRC-5过氧化损伤的保护作用及可能的作用机制。【方法】采用H2O2诱导建立细胞氧化损伤模型,应用四唑蓝快速比色法(MTT法)检测细胞存活率,通过检测细胞培养液中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)活性及丙二醛(MDA)含量,来确定P4对过氧化损伤MRC-5细胞的保护作用,并利用电镜观察细胞形态学变化。【结果】1mmol·L-1H2O2孵育24h可显著诱导MRC-5细胞损伤,使细胞存活力下降到22.47%,细胞经不同浓度的抗氧化肽P4(4、20、100μg·mL-1)与H2O2共孵育后,特别是100μg·mL-1(高剂量组)抗氧化肽P4可使细胞存活率达到44.77%。同时,提高乳清蛋白抗氧化肽P4的浓度,可促进受损的MRC-5细胞修复,提高了SOD、CAT、GSH-Px酶活性,降低MDA含量。扫描电镜和透射电镜观察结果也表明,一定浓度的乳清抗氧化肽对MRC-5细胞具有保护作用。【结论】乳清抗氧化肽通过拮抗H2O2而对MRC-5的过氧化损伤具有保护作用。     

Effects of plastic film mulching on soil greenhouse gases(CO_2,CH_4 and N_2O) concentration within soil profiles in maize fields on the Loess Plateau,China

To better understand the effects of plastic film mulching on soil greenhouse gases(GHGs) emissions,we compared seasonal and vertical variations of GHG concentrations at seven soil depths in maize(Zea mays L.) fields at Changwu station in Shaanxi,a semi-humid region,between 2012 and 2013.Gas samples were taken simultaneously every one week from non-mulched(BP) and plastic film-mulched(FM) field plots.The results showed that the concentration of GHGs varied distinctly at the soil-atmosphere interface and in the soil profile during the maize growing season(MS).Both carbon dioxide(CO_2) and nitrous oxide(N_2O) concentrations increased with increasement of soil depth,while the methane(CH_4)concentrations decreased with increasement of soil depth.A strong seasonal variation pattern was found for CO_2 and N_2O concentrations,as compared to an inconspicuous seasonal variation of CH_4 concentrations.The mean CO_2 and N_2O concentrations were higher,but the mean CH_4 concentration in the soil profiles was lower in the FM plots than in the BP plots.The results of this study suggested that plastic film mulching significantly increased the potential emissions of CO_2and N_2O from the soil,and promoted CH_4 absorption by the soil,particularly during the MS.     

羟基蛋氨酸螯合铜/锰/锌对产蛋鸡蛋壳品质、酶活及微量元素沉积的影响

为研究日粮中有机（羟基蛋氨酸螯合）铜、锰和锌等量替代其硫酸盐对产蛋高峰期蛋鸡的影响,试验选用108只37周龄海兰褐商品蛋鸡,分为2个处理。对照组在基础日粮的基础上添加10、30和30 mg/kg硫酸盐形式的Cu、Mn和Zn,处理组采用蛋氨酸羟基类似物螯合Cu、Mn和Zn等量替代其硫酸盐形式。试验各处理的蛋氨酸当量相同,...     

Strategies for timing nitrogen fertilization of pear trees based on the distribution,storage, and remobilization of ~(15)N from seasonal application of (~(15)NH_4)_2SO_4

In order to improve the management of nitrogen(N) fertilization in pear orchards, we investigated the effects of application timing on the distribution, storage, and remobilization of N in mature pear trees in a field experiment at Jingtai County, Gansu Province, China. Nine trees were selected for the experiment and each received equal aliquots of 83.33 g N in the autumn, spring, and summer, with ~(15)N-labeled(NH_4)_2SO_4 used in one of the aliquots each season. Results showed that the(~(15)NH_4)_2SO_4 applied in the autumn remained in the soil during the winter. In the following spring this N was absorbed and rapidly remobilized into each organ, especially new organs(leaves, fruit and new shoots). The ~(15)N supplied in spring was rapidly transported to developing fruit between the young fruit and fruit enlargement stages. ~(15)N from the summer application of fertilizer was mainly stored in the coarse roots over the winter, then was mobilized to support growth of new organs in spring. In conclusion, for pear trees we recommend that the autumn application of N-fertilizer be soon after fruit harvest in order to increase N stores in fine roots. Spring application should be between full bloom and the young fruit stages to meet the high N demands of developing fruit. Summer application of fertilizer at the fruit enlargement stage does not contemporaneously affect the growth of pears, but increases the N stored in coarse roots, and in turn the amount available for remobilization in spring.