基质栽培营养液氮磷钾补充水平对番茄养分吸收及产量品质影响

温室条件下,采用基质袋式栽培方式(长12.7 m、宽30 cm、高20 cm),通过改变营养液KNO_3与NH_4H_2PO_4含量得到4个不同营养液氮磷钾补充水平,各处理物质的量浓度比分别为:CK为Ca(NO_3)_2·4H_2O:KNO_3:NH_4H_2PO_4:MgSO_4·7H_2O=4.00:6.00:1.00:2.00,T1为Ca(NO_3)_2·4H_2O:KNO_3:NH_4H_2PO_4:MgSO_4·7H_2O=4.00:4.00:0.80:2.00,T2 为Ca(NO_3)_2·4H_2O:KNO_3:NH_4H_2PO_4:MgSO_4·7H2O=4.00:8.00:1.20:2.00,T3 为Ca(NO_3)2·4H_2O:KNsdfO_3:NH_4H_2PO_4: MgSO_4·7H_2O=4.00:10.00:1.40:2.00;研究营养液氮磷钾补充水平对基质栽培番茄品质、产量及养分吸收利用影响。结果表明,提高营养液氮磷钾水平可促进番茄各器官对氮磷钾吸收,超量施用抑制氮磷钾吸收;果实可溶性蛋白、维生素C、还原糖、可溶性总糖含量均随营养液氮磷钾补充水平提高呈先增后降趋势,而可溶性固形物与硝酸盐含量逐渐增加;各处理间单果重、产量差异显著;与CK相比,T2单果重增加6.85%、产量增加13.10%,T3单果重减少2.29%、产量减少2.92%,且存在显著差异。综合考虑番茄养分吸收利用、品质和产量等因素,在试验条件下,T2处理营养液氮磷钾补充水平最佳,推荐用量为:KNO3 8 mmol·L~(-1)、NH_4H_2PO_4 1.2 mmol·L~(-1)、Ca(NO_3)_2 ·4H_2O_4 mmol·L~(-1)、MgSO_4·7H_2O_2 mmol·L~(-1)。     

氮肥形态及配比对花椰菜生长和光合特性的影响

以春茬花椰菜为试验材料,研究了氮肥形态及配比对其干物质积累、根系生长、叶片光合色素含量以及光合作用的影响.结果表明:与单一氮源相比,硝态氮肥与铵态氮肥混合施用更有利于花椰菜干物质量的积累;硝态氮肥与铵态氮肥相比,前者有利于植株根的伸长,后者有利于根的加粗,而两者配合施用更有利于植株根系生长;NO3--N∶NH4+-N=3∶7～5∶5时花椰菜叶片叶绿素含量较高,净光合速率显著高于其它处理;单一氮源、NO3--N∶NH4+-N=7∶3处理时的光合速率均下降,其中,铵态氮处理光合速率降低的原因主要是非气孔因素,而其它处理主要是气孔因素.因此,硝态氮肥与铵态氮肥以3∶7～5∶5配施比单一形态氮肥更有利于花椰菜的生长和干物质积累,提高叶绿素含量和净光合速率.     

(111)晶面暴露的NiO纳米催化剂的制备及其CO催化氧化性能

采用溶剂热法,以Ni(NO_3)_3·6H_2O、均苯三甲酸以及N,N-二甲基甲酰胺(DMF)为原料快速合成金属有机骨架材料Ni_3(BTC)_2·12H_2O晶体。以Ni_3(BTC)_2·12H_2O为前体,通过焙烧得到具有(111)面的NiO颗粒用于CO催化氧化反应,并与由硝酸镍热解得到的NiO(R)催化剂进行对比。通过X射线衍射(XRD)、N_2物理吸附-脱附、透射电子显微镜(TEM)以及X射线光电子能谱(XPS)等方法对具有(111)面的NiO颗粒的组成、结构和形貌进行表征。CO催化氧化结果表明,具有(111)面的NiO颗粒的催化活性优于普通NiO催化剂的催化活性。     

Comparison of calculated and measured ion densities on the dayside of venus

Datafrom the Pioneer Venus ion mass spectrometers are compared with model calculations of the ion density distributions appropriate for daytime conditions. The model assumes diffusive equilibrium upper boundary conditions for the major ions (O(2)(+), O(+), CO(2)(+), He(+), and H(+)); the agreement between the calculated and measured gross behavior of these ions is reasonably good except for H(+), which may be influenced strongly by convective transport processes. The distributions of five minor ions (C(+), N(+), NO(+), CO(+), and N(2)(+)) are also calculated for the chemically controlled region ( less, similar 200 kilometers); the agreements are, in general, poor, an indication that our present understanding of the Venus minor ion chemistry is still incomplete.     

有机肥对日光温室生菜地土壤温室气体排放的影响

采用静态箱-气相色谱法研究日光温室生菜地不施肥(CK)、施用腐熟鸡粪(H)、羊粪(S)、鸡粪+秸秆(HSt)、羊粪+秸秆(SSt)、羊粪+鸡粪+秸秆(SHSt)等6种处理的温室气体排放通量及增温潜势(GWP)。结果表明:(1)H、S、HSt处理的N_2O排放通量在施肥前、中、后期呈近"V"型变化,CK、SSt、SHSt呈倒"V"型变化;S、SSt、SHSt处理的CH_4排放通量呈倒"V"型变化;CO_2排放通量均呈近"V"型变化(SSt除外);(2)施肥前期,HSt、S、H、SHSt、SSt处理的N_2O排放通量分别较CK显著增加2.89、2.32、1.48、1.17、0.95倍;S、H的CH_4排放通量显著高于CK处理1.91、1.11倍;H的CO_2排放通量显著低于CK处理3.88倍。施肥中期,HSt的N_2O排放通量显著低于CK处理1.93倍;SHSt的CH_4排放通量显著高于CK处理1.34倍;各施肥处理的CO_2排放通量与CK差异不显著。施肥后期,H的N_2O排放通量显著高于CK处理1.10倍;SHSt、SSt、S的CH_4排放通量显著低于CK处理3.76、5.25、5.58倍;HSt的CO_2排放通量显著高于CK处理8.61倍;(3)全球增温潜势(GWP)按照SSHStHStSStCKH依次减小,建议施用腐熟鸡粪、鸡粪加秸秆及羊粪加秸秆。     

CO2浓度对冬小麦氮代谢的影响

 采用全硝态氮霍格兰营养液为培养基质，在自然光与遮光条件下分别对冬小麦植株进行增加CO2浓度处理，分期测定其体内NO3--N、NH4+-N、全氮量、吸氮量及硝酸还原酶活性（NRA），研究CO2对小麦氮代谢的影响。结果表明，无论遮光与否，增加CO2浓度均增强了植株对NO3--N的吸收、同化能力。但对地上部与根部的影响不同，施加CO2，地上部硝态氮、铵态氮浓度及NRA均有所降低，而植株由溶液中吸收的硝态氮及吸氮总量增加；与地上部相比，CO2对根部硝态氮、铵态氮浓度影响较小，趋势相似；培养期间，施CO2极显著的提高根部NRA，增强根部对硝态氮的同化能力。     

Effect of CO2 Concentration on Nitrogen Metabolism of Winter Wheat

Hoagland＇s solution was used as water culture medium to study the effect of CO2 concentration on nitrate metabolism of wheat under natural light and light-shaded conditions. NO3^-N, NH4^＋-N, nitrate reductase activity, total uptake N by wheat plants during solution cultural period and total N in plants were determined for comprehensive evaluation of the effect. Results showed that under both natural light and light-shaded conditions, addition of CO2 increased NO3^-N uptake and its assimilative capabilities by plants. However, there were some difference between shoots and roots. With increase of CO2 concentration, the concentration of NO3^-N and NH4^＋-N as well as nitrate reductase activity were all decreased for shoots while the difference was not so distinct in roots, and the nitrate reductase activity was not decreased, but increased. Since NO3^-N uptake by plants from the solution and the total N in plants were much higher by CO2 addition, it may be concluded that addition of CO2 has resulted in rise of nitrate absorption, assimilation and metabolism of wheat.     

氯离子对马铃薯同化~(14)CO_2及吸收~(32)P和~(15)NO_3~-的影响

采用同位素示踪技术,研究了Cl对马铃薯的同化作用及吸收养分的影响。结果表明,培养液中Cl浓度过高会影响马铃薯对~(14)CO_2同化,减少对~(15)NO_5和H_2 ~(32)PO_4PO_4的吸收。     

用两室根箱系统法对土壤氮素转化的空间变异及N2O的产生之初探

用特制的带有9根采气管的两室根箱系统,采集和分析根箱中9个不同部位土壤空气中N2O的浓度,结合使用具有选择性的硝化抑制剂(包括低浓度的C2H2和DCD),研究在不同铵态氮水平下的硝化过程及其对N2O气体释放的贡献;结合使用高浓度的C2H2,抑制反硝化过程中N2O到N2的还原,研究在不同铵态氮水平下的反硝化过程及其对N2O气体释放的贡献。同时还研究铵态氮、硝态氮转化及其释放N2O气体的时间和空间变异性和植物对它们的影响。结果表明,根箱系统结合使用抑制剂的方法,是一种研究土壤氮素转化过程、N2O气体释放及植物对前两者影响的有效方法。     

盐渍化土壤上不同类型氮肥氨挥发损失特征研究

在室内采用"磷酸甘油-海绵通气法",对不同类型氮肥在典型非盐渍化土壤、盐化土壤,碱化土壤上的氨挥发损失特征进行研究.结果表明:(1)在相同的施氮量情况下,占施入量1.34;～27.74;的氮以NH3的形式挥发损失;(2)除硝酸钙外,随着土壤盐渍化程度的增加,不同类型氮肥氨挥发损失均随之增加,挥发速率与盐渍化类型有关;(3)不同盐渍化类型土壤上的氨挥发量均为碳酸氢氨＞尿素＞硝酸铵,硝酸钙几乎不发生氨挥发;因此盐渍土上选择硝态氮肥不失为降低氨挥发损失的一种选择;(4)过量盐分的存在对于氮肥硝化作用的抑制是导致盐渍化土壤上氮肥氨挥发损失增加的主要原因.     

Apollo lunar module engine exhaust products

Organic combustion products generated by the lunar module descent engine, which burns a 1:1 mixture of unsymmetrical dimethylhydrazine fuel and nitrogen tetroxide oxidizer, have been analyzed. The major gaseous combustion products found were ammonia, water, carbon monoxide, nitrous oxide, oxygen, carbon dioxide, and nitric oxide. The minor products were acetylene, hydrogen cyanide, ethylene, formaldehyde, propadiene, ketene, cyanous acid, hydrazoic acid, various methylamines, acetaldehyde, methyl nitrite, formic acid, nitrous acid, butadiyne, nitrilohydrazines, nitromethane, and nitrosohydrazines with other oxidized derivatives of unsymmetrical dimethylhydrazine and hydrazine. The ion intensities of the various species in all mass spectra were estimated as the following concentrations: the gases (NH(3), H(2)O, CO, NO, O(2), CO(2), and NO(2)), 87.7 percent; compounds of C, H, and O, 6.0 percent; and compounds of C, H, and N (with traces of O), 5.8 percent.     

不同氮素水平对濒危植物黄檗幼苗光合荧光特性的影响

为了探讨不同氮素水平对黄檗幼苗光合作用的影响,采用液体培养的方法,研究了4种不同的氮素(以NH4NO3计)水平下黄檗幼苗叶绿素含量以及光合和荧光特性的差异。结果显示:随着氮浓度的增加,叶绿素a、叶绿素b、类胡萝卜素和总叶绿素含量都是先升高后降低,都在N8(4 mmol/L的NH4NO3)时达到最大值,其次是N16(8 mmol/L的NH4NO3)、N4(2 mmol/L的NH4NO3)和N1(0.5 mmol/L的NH4NO3),而叶绿素a/b在N4时最大。N4、N8和N16处理条件下黄檗幼苗的光响应曲线变化趋势基本一致,其净光合速率(Pn)都随光合有效辐射(PAR)的增加而迅速增大,之后增速明显下降,最后呈平缓的变化趋势,N8的最大净光合速率(Pnmax)最高,其次是N16,最后是N4;N1的光响应曲线则略有不同,其Pn值达到最大值之后却随PAR的增加而逐渐下降,且N1的Pnmax值最低。N8条件下的光饱合点、气孔导度都最高,表观量子效率和胞间二氧化碳浓度较高且光补偿点和暗呼吸速率较低。随着氮浓度的增加,最大荧光、可变荧光、光化学猝灭系数、光系统Ⅱ原初光能转换效率、PSⅡ量子效率和表观电子传递速率值都是先升高后降低,在N8时达到最大值,且在N1时最低,初始荧光和非光化学猝灭系数值则是N4最高。结果表明,适当增加供氮水平可以显著提高黄檗幼苗的光合能力,但过高的氮素供给反而不利于幼苗生长,N8条件最适合幼苗生长。      

Nightglow in the upper atmosphere of Mars and implications for atmospheric transport

We detected light emissions in the nightside martian atmosphere with the SPICAM (spectroscopy for the investigation of the characteristics of the atmosphere of Mars) ultraviolet (UV) spectrometer on board the Mars Express. The UV spectrum of this nightglow is composed of hydrogen Lyman alpha emission (121.6 nanometers) and the gamma and delta bands of nitric oxide (NO) (190 to 270 nanometers) produced when N and O atoms combine to produce the NO molecule. N and O atoms are produced by extreme UV photodissociation of O2, CO2, and N2 in the dayside upper atmosphere and transported to the night side. The NO emission is brightest in the winter south polar night because of continuous downward transport of air in this region at night during winter and because of freezing at ground level.     

氮素形态对黄瓜幼苗光合特性及碳水化合物代谢的影响

用营养液培养的方法,研究了同一氮素水平不同氮素形态比例对黄瓜幼苗光合特性及碳水化合物代谢的影响。结果表明:与单一氮源相比,当NO3--N∶NH4+-N为75∶25时,黄瓜幼苗叶片叶绿素含量、净光合速率、气孔导度、胞间CO2浓度最大。单一供NH4+-N营养净光合速率高于单一供NO3--N。当NO3--N∶NH4+-N为50∶50时,可溶性糖、淀粉含量最大,单一NH4+-N最低。氮素形态对黄瓜根、茎、叶中的可溶性糖和叶片中的淀粉含量影响较大,但对根、茎中的淀粉含量影响较小。     

Hydrogen radicals, nitrogen radicals, and the production of O3 in the upper troposphere

The concentrations of the hydrogen radicals OH and HO2 in the middle and upper troposphere were measured simultaneously with those of NO, O3, CO, H2O, CH4, non-methane hydrocarbons, and with the ultraviolet and visible radiation field. The data allow a direct examination of the processes that produce O3 in this region of the atmosphere. Comparison of the measured concentrations of OH and HO2 with calculations based on their production from water vapor, ozone, and methane demonstrate that these sources are insufficient to explain the observed radical concentrations in the upper troposphere. The photolysis of carbonyl and peroxide compounds transported to this region from the lower troposphere may provide the source of HOx required to sustain the measured abundances of these radical species. The mechanism by which NO affects the production of O3 is also illustrated by the measurements. In the upper tropospheric air masses sampled, the production rate for ozone (determined from the measured concentrations of HO2 and NO) is calculated to be about 1 part per billion by volume each day. This production rate is faster than previously thought and implies that anthropogenic activities that add NO to the upper troposphere, such as biomass burning and aviation, will lead to production of more O3 than expected.     

pH值和氮素对莱氏衣藻(Chlamydomonas reinhardtii)胞外碳酸酐酶活性的影响

对莱氏衣藻在不同ｐＨ值下胞外碳酸酐酶活性变化的观测表明,在ｐＨ７．２时诱导的酶活性最高,而ｐＨ５．５时诱导的酶活性明显低于ｐＨ７．２和ｐＨ９．０时诱导的酶活性。氮素对胞外碳酸酐酶基因表达也具有重要调控作用,在从高ＣＯ２浓度转入低ＣＯ２浓度时,缺氮或低氮浓度抑制胞外碳酸酐酶活性的增加,铵态氮诱导的酶活性高于硝态氮。     

结晶有机肥与复合肥、尿素在土壤中养分淋失的比较研究

对尿素、复合肥、结晶有机肥进行了NO3 N、NH4 N及K的模拟淋失试验。从NO3 N淋失总量看 ,顺序为 :复合肥处理 (6 2 9mg ) >尿素处理 (5 86mg) >结晶肥处理 (36 8mg) ,尿素处理和复合肥处理分别为结晶肥处理的 1.5 9倍和 1.71倍 ;NH4 N总淋失量顺序为 :尿素处理 (5 3mg) >复合肥处理 (41mg) >结晶肥处理 (2 0mg) ,即尿素处理和复合肥处理分别为结晶肥处理的 2 .6 4倍和 2 .0 5倍 ;K淋失总量顺序为尿素处理 (398mg) >复合肥处理 (30 3mg) >结晶肥处理 (188mg) ,尿素处理和复合肥处理分别为结晶肥处理的 2 .12倍和 1.6 1倍。进一步由上、下层土体的NO3 N、NH4 N、K含量综合比较后可知 ,尿素处理后土体对 3种养分保持能力最差 ,复合肥处理较好 ,结晶肥处理最强。结果说明 ,结晶肥明显地减少了NO3 N、NH4 N、K在土壤中的淋失 ,对提高肥料利用率有重要意义     

Isotopic composition of the martian atmosphere

Results from the neutral mass spectrometer carried on the aeroshell of Viking 1 show evidence for NO in the upper atmosphere of Mars and indicate that the isotopic composition of carbon and oxygen is similar to that of Earth. Mars is enriched in (15)N relative to Earth by about 75 percent, a consequence of escape that implies an initial abundance of nitrogen equivalent to a partial pressure of at least 2 millibars. The initial abundance of oxygen present either as CO(2) or H(2)O must be equivalent to an exchangeable atmospheric pressure of at least 2 bars in order to inhibit escape-related enrichment of (18)O.     

Biogenic methane, hydrogen escape, and the irreversible oxidation of early Earth

The low O2 content of the Archean atmosphere implies that methane should have been present at levels approximately 10(2) to 10(3) parts per million volume (ppmv) (compared with 1.7 ppmv today) given a plausible biogenic source. CH4 is favored as the greenhouse gas that countered the lower luminosity of the early Sun. But abundant CH4 implies that hydrogen escapes to space (upward arrow space) orders of magnitude faster than today. Such reductant loss oxidizes the Earth. Photosynthesis splits water into O2 and H, and methanogenesis transfers the H into CH4. Hydrogen escape after CH4 photolysis, therefore, causes a net gain of oxygen [CO2 + 2H2O --> CH4 + 2O2 --> CO2 + O2 + 4H(upward arrow space)]. Expected irreversible oxidation (approximately 10(12) to 10(13) moles oxygen per year) may help explain how Earth's surface environment became irreversibly oxidized.     

Ionosphere of venus: first observations of day-night variations of the ion composition

The Bennett radio-frequency ion mass spectrometer on the Pioneer Venus orbiter is returning the first direct composition evidence of the processes responsible for the formation and maintenance of the nightside ionosphere. Early results from predusk through the nightside in the solar zenith angle range 63 degrees (dusk) to 120 degrees (dawn) reveal that, as on the dayside, the lower nightside ionosphere consists of F(1)and F(2) layers dominated by O(2)(+) and O(+), respectively. Also like the dayside, the nightside composition includes distributions of NO(+), C(+), N(+), H(+), He(+), CO(2)(+), and 28(+) (a combination of CO(+) and N(2)(+)). The surprising abundance of the nightside ionosphere appears to be maintained by the transport of O(+) from the dayside, leading also to the formation of O(2)(+) through charge exchange with CO(2). Above the exobase, the upper nightside ionosphere exhibits dramatic variability in apparent response to variations in the solar wind and interplanetary magnetic field, with the ionopause extending to several thousand kilometers on one orbit, followed by the complete rertnoval of thermal ions to altitudes below 200 kilometers on the succeeding orbit, 24 hours later. In the upper ionosphere, considerable structure is evident in many of the nightside ion profiles. Also evident are horizontal ion drifts with velocities up to the order of 1 kilometer per second. Whereas the duskside ionopause is dominated by O(+) H(+) dominates the topside on the dawnside of the antisolar point, indicating two separate regions for ion depletion in the magnetic tail regions.