不同气体组合对杏果实贮藏品质的影响

以银白和苹果白杏果实为试材,探讨了不同气调处理,即气体O2与CO2 6种比例组合:3% O2(CA1)、3% O2+2%CO2(CA2)、3%O2+4%CO2(CA3)、8%O2 (CA4)、8%O2+2%CO2(CA5)、8%O2+4%CO2(CA6)及对照(21% O2)对杏果实贮藏品质的影响.结果表明:在相同的贮藏时间内,气调贮藏可缓解银白杏果实硬度的下降,CA6处理的作用最明显,其次为CA3和CA4处理;冷藏苹果白杏果实的硬度在贮藏后期增加,气调贮藏果实的硬度降低,但处理间的差异不显著.在贮藏30 d内,冷藏银白杏果实的可溶性固形物和VC含量仍较高,贮藏30～45 d两者明显下降,气调贮藏可缓解其下降,CA3处理的效果最明显;气调贮藏对苹果白杏果实可溶性固形物和VC含量的影响不大.气调贮藏可缓解银白和苹果白杏果实可滴定酸含量的下降.可见,CA3处理对维持银白杏果实贮藏品质有较好的作用;气调贮藏对苹果白杏果实品质的影响表现在可滴定酸方面,CA1和CA2的效果较好.     

Detection of near-atmospheric concentrations of CO2 by an olfactory subsystem in the mouse

Carbon dioxide (CO2) is an important environmental cue for many organisms but is odorless to humans. It remains unclear whether the mammalian olfactory system can detect CO2 at concentrations around the average atmospheric level (0.038%). We demonstrated the expression of carbonic anhydrase type II (CAII), an enzyme that catabolizes CO2, in a subset of mouse olfactory neurons that express guanylyl cyclase D (GC-D+ neurons) and project axons to necklace glomeruli in the olfactory bulb. Exposure to CO2 activated these GC-D+ neurons, and exposure of a mouse to CO2 activated bulbar neurons associated with necklace glomeruli. Behavioral tests revealed CO2 detection thresholds of approximately 0.066%, and this sensitive CO2 detection required CAII activity. We conclude that mice detect CO2 at near-atmospheric concentrations through the olfactory subsystem of GC-D+ neurons.     

山西太岳山核桃楸光合特性的研究

用Li 6 4 0 0光合作用测定系统对自然生长的核桃楸壮龄林木的光合作用进行测定 .结果如下 :①核桃楸的光合速率在 1d内有两个峰值 ,两个光合峰高度接近 ,上午的光合速率峰持续时间较下午的长 .叶片气孔导度、蒸腾速率与光合速率间表现出较强的正相关 ,日变化曲线呈双峰型 .叶片胞内CO2 浓度受气孔导度和大气CO2 浓度的双重影响 ,呈现出早晚大幅升高 ,正午有 1h的峰值的日变化进程 .②在控制条件下 ,叶片的光合速率在低光合有效辐射 (0～ 5 0μmol (m2 ·s)下 ,表现出随CO2 浓度增加而降低的趋势 ;高出此光合有效辐射值后 ,光合速率随CO2 浓度的增加呈抛物线变化 ,最高点对应的光合有效辐射下的CO2 饱和点 ,且随光合有效辐射的增加CO2 饱和点增高 .当光合有效辐射为0～ 12 0 0 μmol (m2 ·s)时 ,叶片的气孔导度表现出随光合有效辐射的增加而增大 ,随CO2 浓度的增加而减小的趋势 ;光合有效辐射超过 12 0 0 μmol (m2 ·s)后 ,气孔导度随光合有效辐射、CO2 浓度的增加而降低 .叶片蒸腾速率的变化趋势与气孔导度类似 .     

CO_2浓度升高对丁香光合生理特性的影响

在人工控制CO2浓度梯度条件下,研究了丁香叶片光合速率、气孔导度和蒸腾速率对CO2浓度升高的响应。结果表明:CO2浓度升高对丁香的光合生理有明显的影响,当CO2浓度为当前浓度至加倍(360～720μmol﹒mol-1)范围内,各光合指标随CO2浓度增加而增大,继续升高CO2浓度则开始下降。在较强光照下,升高CO2浓度对丁香有"气肥"作用。丁香达光合能力值适宜的光合有效辐射强度为1000μmol﹒m-2s-1,CO2浓度为700μmol﹒mol-1。未来CO2浓度升高,不仅有利于丁香的光合作用,而且可提高丁香的水分利用效率。     

Carbon Dioxide Transport by Ocean Currents at 25{degrees}N Latitude in the Atlantic Ocean

Measured concentrations of CO(2), O(2), and related chemical species in a section across the Florida Straits and in the open Atlantic Ocean at approximately 25 degrees N, have been combined with estimates of oceanic mass transport to estimate both the gross transport of CO(2) by the ocean at this latitude and the net CO(2) flux from exchange with the atmosphere. The northward flux was 63.9 x 10(6) moles per second(mol/s); the southward flux was 64.6 x 10(6) mol/s. These values yield a net CO(2) flux of 0.7 x 10(6) mol/s (0.26 +/- 0.03 gigaton of C per year) southward. The North Atlantic Ocean has been considered to be a strong sink for atmospheric CO(2), yet these results show that the net flux in 1988 across 25 degrees N was small. For O(2) the equivalent signal is 4.89 x 10(6) mol/s northward and 6.97 x 10(6) mol/s southward, and the net transport is 2.08 x 10(6) mol/s or three times the net CO(2) flux. These data suggest that the North Atlantic Ocean is today a relatively small sink for atmospheric CO(2), in spite of its large heat loss, but a larger sink for O(2) because of the additive effects of chemical and thermal pumping on the CO(2) cycle but their near equal and opposite effects on the CO(2) cycle.     

环境条件对乳清蛋白凝胶特性和微观结构的影响

 【目的】研究离子种类、离子强度、加热温度、pH、蛋白浓度等条件对乳清蛋白凝胶的质地性质、持水性、微观结构的影响。【方法】利用质构仪测定添加不同浓度的NaCl和CaCl2对所形成的乳清蛋白凝胶硬度、弹性、内聚性的影响,利用扫描电镜观察凝胶微观结构。【结果】盐对凝胶性质影响很大,相同条件下钠盐形成凝胶需较高浓度且弹性和持水性好于钙盐凝胶;蛋白浓度达到8%～10%时凝胶质地较好。在微观结构上钠盐凝胶比钙盐凝胶内部更加致密结实。这在宏观上表现为钠盐凝胶硬度相对较大,持水性更好。【结论】钠盐凝胶具有更好的凝胶质地和功能性质。     

Composition and structure of the martian atmosphere: preliminary results from viking 1

Results from the aeroshell-mounted neutral mass spectrometer on Viking I indicate that the upper atmosphere of Mars is composed mainly of CO(2) with trace quantities of N(2), Ar, O, O(2), and CO. The mixing ratios by volume relative to CO(2) for N(2), Ar, and O(2) are about 0.06, 0.015, and 0.003, respectively, at an altitude near 135 kilometers. Molecular oxygen (O(2)(+)) is a major component of the ionosphere according to results from the retarding potential analyzer. The atmosphere between 140 and 200 kilometers has an average temperature of about 180 degrees +/- 20 degrees K. Atmospheric pressure at the landing site for Viking 1 was 7.3 millibars at an air temperature of 241 degrees K. The descent data are consistent with the view that CO(2) should be the major constituent of the lower martian atmosphere.     

大气CO2浓度升高和氮肥管理对稻麦轮作系统土壤线虫群落组成的影响

 【目的】揭示大气CO2浓度升高和氮肥管理对地下生态系统的影响。【方法】采用中国稻麦轮作FACE（Free-Air CO2 Enrichment）系统平台,开展了大气CO2浓度升高和氮肥管理对土壤线虫群落组成影响的研究。【结果】在稻麦轮作系统共观察到线虫35属,15个功能团。拟丽突属、真头叶属、丝尾属和潜根属为优势属,其中丝尾属和真头叶属对CO2浓度升高和氮肥管理反应敏感。在CO2浓度升高条件下土壤线虫总数、功能团Fu2和Om4的线虫多度均显著增加,其中Fu2多度在CO2和氮肥的交互影响下变化明显。【结论】CO2浓度升高和氮肥管理改变了土壤腐屑食物网的结构和有机质的分解途径。高氮条件下,CO2浓度升高降低了线虫的通路指数（CI）,细菌为主的分解通道在小麦季的FACE（HN）处理中占优势。不同施氮水平对线虫结构指数（SI）产生显著影响,低氮条件下较高的SI值表明土壤环境受到的扰动较小,食物网处于结构化状态。     

CO2倍增对鼓槌石斛光合作用特性的影响

研究高浓度CO2对鼓槌石斛光合作用的影响,对鼓槌石斛野生资源保护和开发利用具有重要的科学意义。CO2加倍处理后(30 d),利用气体交换技术和叶绿素荧光技术测定鼓槌石斛净光合速率、蒸腾速率、水分利用效率和叶绿素荧光等参数。结果表明:高浓度CO2使鼓槌石斛净光合效率(Pn)、胞间CO2浓度(Ci)和水分利用率(WUE)升高,而气孔导度(Cond)和蒸腾效率(Tr)降低;通过慢速荧光诱导动力学曲线得出鼓槌石斛最大光化学效率(Fv/Fm)变化不显著,实际光化学效率(Yield)和电子传递速率(ETR)升高,光化学淬灭系数(qP)显著上升,而非光化学淬灭系数(qN)显著下降。表明鼓槌石斛在未来高CO2和干旱环境条件下将具有良好的适应能力和生长优势。     

The hydroperoxyl radical in atmospheric chemical dynamics: reaction with carbon monoxide

From measurements of the photochemical rate of production of CO(2)(16,18) and CO(2)(16,16), produced from the low intensity photolysis of mixtures of CO, H(2)O, Ar, and O(2)(18,18), the rate constant for the reaction HO(2) + CO --> CO(2) + OH has been determined at 300 degrees K to be less than or equal to 10(-20) cubic centimeter per molecule per second. These measurements indicate that the reaction of thermalized HO(2) is of negligible importance as a sink mechanism for converting CO to CO(2) in either the troposphere or the stratosphere.     

Leaf photosynthesis and yield components of mung bean under fully open-air elevated[CO_2]

Mung bean(Vigna radiata L.) has the potential to establish symbiosis with rhizobia,and symbiotic association of soil micro flora may facilitate the photosynthesis and plant growth response to elevated[CO_2].Mung bean was grown at either ambient CO_2 400 μmol mol~(-1) or[CO_2]((550+17) μmol mol~(-1)) under free air carbon dioxide enrichment(FACE) experimental facility in North China.Elevated[CO_2]increased net photosynthetic rate(P_n),water use efficiency(WUE) and the non-photochemical quenching(NPQ) of upper most fully-expanded leaves,but decreased stomatal conductance(G_s),intrinsic efficiency of PSII(F_v '/F_m'),quantum yield of PSII(φ_(PSll)) and proportion of open PSII reaction centers(q_p).At elevated[CO_2],the decrease of F_v'/F_m',φ_(PSII),q_p at the bloom stage were smaller than that at the pod stage.On the other hand,P_n was increased at elevated[CO_2]by 18.7 and 7.4%at full bloom(R2) and pod maturity stages(R4),respectively.From these findings,we concluded that as a legume despite greater nutrient supply to the carbon assimilation at elevated[CO_2],photosynthetic capacity of mung bean was still suppressed under elevated[CO_2]particularly at pod maturity stage but plant biomass and yield was increased by 11.6 and 14.2%,respectively.Further,these findings suggest that even under higher nutrient acquisition systems such as legumes,nutrient assimilation does not match carbon assimilation under elevated[CO_2]and leads photosynthesis down-regulation to elevated[CO_2].     

Loss of carbon from the deep sea since the Last Glacial Maximum

Deep-ocean carbonate ion concentrations ([CO(3)(2-)]) and carbon isotopic ratios (δ(13)C) place important constraints on past redistributions of carbon in the ocean-land-atmosphere system and hence provide clues to the causes of atmospheric CO(2) concentration changes. However, existing deep-sea [CO(3)(2-)] reconstructions conflict with one another, complicating paleoceanographic interpretations. Here, we present deep-sea [CO(3)(2-)] for five cores from the three major oceans quantified using benthic foraminiferal boron/calcium ratios since the last glacial period. Combined benthic δ(13)C and [CO(3)(2-)] results indicate that deep-sea-released CO(2) during the early deglacial period (17.5 to 14.5 thousand years ago) was preferentially stored in the atmosphere, whereas during the late deglacial period (14 to 10 thousand years ago), besides contributing to the contemporary atmospheric CO(2) rise, a substantial portion of CO(2) released from oceans was absorbed by the terrestrial biosphere.     

不同氮素条件米槁幼苗光合作用对CO_2响应特征

为探求氮素对米槁幼苗叶片CO_2响应特征影响,以1年生米槁幼苗为试验材料,采用砂培法,利用Li-6400光合仪测定4种不同氮浓度胁迫下米槁叶片CO_2响应曲线及气孔导度(Gs)、胞间CO_2浓度(Ci)、蒸腾速率(Tr)等相关光合参数,并运用直角双曲线、非直角双曲线、直角双曲线修正3种模型拟合米槁叶片CO_2响应曲线。结果显示,直角双曲线修正模型拟合米槁叶片CO_2响应曲线,可克服直角双曲线模型未考虑曲线凸度缺陷及无法拟合CO_2过饱和净光合速率(Pn)下降缺点,得到光合参数与实测值相近,直接确定CO_2饱和点(CSP)。在控制外界条件下,各氮处理米槁Ci随叶室内CO_2浓度(Ca)升高呈同步直线上升趋势。同一Ca值下,米槁叶片Ci随氮浓度水平增加而增大。各氮处理下米槁叶片Gs随Ci升高总体呈下降趋势;Tr变化趋势与Gs一致,在同一Ci下,Gs与Tr均随氮浓度增大而增加。米槁叶片Pn随Ci升高逐步升高,但在高Ci阶段Pn略下降,增施氮素可提高米槁叶片CSP、最大净光合速率(Pnmax),降低叶片CO_2补偿点(CCP),表明增施氮素能可强米槁叶片光合作用对CO_2适应幅度,提高CO_2利用效率,促进有机物积累。研究表明,直角双曲线修正模型拟合米槁叶片CO_2响应曲线效果最佳,施氮可有效促进米槁幼苗生长。     

添加有机物料后红壤CO2释放特征与微生物生物量动态

 【目的】对不同有机物料施入红壤后CO2释放特征及几种形态碳、氮变化进行了观测,并分析其相互关系,以阐明添加有机物料后红壤中CO2释放量及几种碳、氮形态的变化特征。【方法】采用室内恒温培养试验,向红壤中添加5种有机物料（猪粪、牛粪、鸡粪、玉米秸秆和小麦秸秆）,培养期间定期采样分析红壤CO2释放量及土壤微生物量碳、氮（SMBC、SMBN）的动态变化。【结果】添加有机物料后,各处理CO2释放速率在培养前期较高,在培养18-20 d后基本趋于稳定。整个培养期间,土壤CO2-C的累积过程符合一级反应动力学方程。添加不同有机物料后红壤CO2潜在释放量从高到低顺序为：小麦秸秆（1.51 g•kg-1）＞玉米秸秆（1.38 g•kg-1）＞猪粪（0.89 g•kg-1）＞鸡粪（0.78 g•kg-1）＞牛粪（0.50 g•kg-1）。添加几种有机物料后红壤CO2释放量存在显著差异,秸秆类有机物料分解释放CO2量相当于动物有机肥的2倍以上,其中小麦秸秆最高,牛粪最低,且有机物料分解释放CO2量与SMBC、SMBN、土壤可溶性有机碳（WSOC）和有机物料C/N呈显著相关。【结论】等碳量的有机物料施入红壤后能显著提高土壤CO2的释放速率和释放量,且土壤CO2释放量与土壤微生物量、可溶性碳和有机物料的C/N紧密相关。添加有机物料处理,土壤微生物生物量和碳源、氮源的有效性较高,有利于土壤养分的转化和释放。     

High-throughput synthesis of zeolitic imidazolate frameworks and application to CO2 capture

A high-throughput protocol was developed for the synthesis of zeolitic imidazolate frameworks (ZIFs). Twenty-five different ZIF crystals were synthesized from only 9600 microreactions of either zinc(II)/cobalt(II) and imidazolate/imidazolate-type linkers. All of the ZIF structures have tetrahedral frameworks: 10 of which have two different links (heterolinks), 16 of which are previously unobserved compositions and structures, and 5 of which have topologies as yet unobserved in zeolites. Members of a selection of these ZIFs (termed ZIF-68, ZIF-69, and ZIF-70) have high thermal stability (up to 390 degrees C) and chemical stability in refluxing organic and aqueous media. Their frameworks have high porosity (with surface areas up to 1970 square meters per gram), and they exhibit unusual selectivity for CO2 capture from CO2/CO mixtures and extraordinary capacity for storing CO2: 1 liter of ZIF-69 can hold approximately 83 liters of CO2 at 273 kelvin under ambient pressure.     

根际CO_2浓度对网纹甜瓜生长和根系氮代谢的影响

【目的】探讨根际CO2浓度对网纹甜瓜生育的影响。【方法】采用雾培植株根际通CO2处理方式,在开花结果期对网纹甜瓜进行不同浓度的根际CO2处理,研究根际CO2浓度对网纹甜瓜植株生长和根系氮代谢的影响。【结果】在网纹甜瓜果实发育期间,根际2500μL·L-1和5000μL·L-1CO2浓度处理同350μL·L-1(对照)处理相比,植株生长受到明显抑制。根系硝态氮(NO3--N)含量、氨态氮(NH4+-N)含量、ATP酶活性、硝酸还原酶(NR)活性和谷氨酸脱氢酶(GDH)活性均表现出先增后降的变化趋势,且5000μL·L-1处理变化的幅度大于2500μL·L-1处理。根系中可溶性蛋白质含量、谷氨酰胺合成酶(GS)活性、谷草转氨酶(GOT)活性和谷丙转氨酶(GPT)活性在整个处理期间,均随着根际CO2浓度的升高而降低。根际高浓度CO2使根系伤流液中氨基酸的总量和大部分氨基酸的含量下降。【结论】在网纹甜瓜果实发育期间根际CO2浓度长期达到2500μL·L-1以上时,植株生长和果实发育受到抑制,根系对氮的吸收、代谢能力下降,植株氮循环水平降低。     

不同通气方式对马铃薯根际通气状况和生长的影响

采用槽栽方法,以根际全基质栽培为对照(CK),研究了根际自然扩散通气处理(T1)、根际管通气处理(T2)和根际两端通气处理(T3)对大田马铃薯植株生长的影响,并在全生育期测定了植株根际CO2与O2浓度变化。结果表明,在整个生育期,块茎膨大期马铃薯植株根际CO2浓度最高,变化幅度最大;在不同处理之间,根际CO2浓度CK>T1处理>T2处理>T3处理。同时,根际O2浓度与CO2浓度变化趋势相反,且变化幅度很小。T2处理和T3处理马铃薯植株各个生育指标比较接近,均大于对照和T1处理,其中T2处理马铃薯植株的株高、茎粗、生物量和块茎产量均与对照达到显著差异水平。说明根际CO2浓度过度富积可能是影响马铃薯生长的重要因素,增加根际通气性,降低根际CO2浓度,对大田马铃薯植株生长和产量提高有促进作用。     

Weak northern and strong tropical land carbon uptake from vertical profiles of atmospheric CO2

Measurements of midday vertical atmospheric CO2 distributions reveal annual-mean vertical CO2 gradients that are inconsistent with atmospheric models that estimate a large transfer of terrestrial carbon from tropical to northern latitudes. The three models that most closely reproduce the observed annual-mean vertical CO2 gradients estimate weaker northern uptake of -1.5 petagrams of carbon per year (Pg C year(-1)) and weaker tropical emission of +0.1 Pg C year(-1) compared with previous consensus estimates of -2.4 and +1.8 Pg C year(-1), respectively. This suggests that northern terrestrial uptake of industrial CO2 emissions plays a smaller role than previously thought and that, after subtracting land-use emissions, tropical ecosystems may currently be strong sinks for CO2.     

苹果叶片蛋白质双向电泳样品制备方法的比较

 为探索适用于苹果叶片蛋白质组学研究的样品制备方法,比较了三氯乙酸/丙酮沉淀法（TCA）、酚-甲醇/醋酸铵沉淀法和Tris-HCl提取法等3种总蛋白质的提取方法。制备的样品经双向电泳分离采用银染显色。结果3种方法分别得到450、374和1032个蛋白质点。认为Tris-HCl提取法为最适方法,所得图谱背景清晰,蛋白质信息量最大。     

提高CO_2浓度对大花蕙兰生长及光合生理特性的影响

研究了提高CO2浓度对大花蕙兰植株生长和光合生理特性的影响。结果表明:提高CO2浓度会促进大花蕙兰植株的生长发育,增加株高、叶宽和叶长;对花芽的生长具有明显的促进作用,但是并没有明显的提高植株的开花率;会使大花蕙兰的始花期提早,但对花期的长短并没有明显的影响;导致了叶片气孔导度(SC)和蒸腾速率(TR)的下降,净光合速度的提高。