空间电场对植物吸收CO2和生长速度的影响

为研究空间电场对植物吸收CO₂和生长速度的影响，首先采用同位素示踪法，分析了不同空间电场调控营养液栽培的番茄秧吸收CO₂气体和HCO^-₃阴离子的能力，证实了 ¹⁴C—HCO^-₃是一种受控于空间电场变化的阴离子，且空间电场强度的变化方向调控着 ¹⁴C—HCO^-₃阴离子流的流动方向。在此基础上以蕹菜(空心菜)为试验材料，采取空间电场与增施CO₂浓度的参数组合，做对比生长试验，通过红外线CO₂分析法揭示了空间电场的极性对植物吸收CO₂的速度有显著影响，且正向空间电场能显著促进植物对CO₂的吸收，并得到正向空间电场与足量的CO₂浓度相配合能大幅度提高温室蔬菜生长速度，使作物产量倍增的结论，为建立空间电场促进植物生长技术提供理论依据。     

CO2施肥对黄瓜幼苗矿质营养吸收与分配的影响

以土培和砂培黄瓜幼苗为试材，研究CO₂施肥对植株矿质营养吸收和分配的影响。结果表明：每天上午以1100±100 μl/L CO₂浓度施肥3 h或上、下午各施肥3 h明显降低植株各部位多数矿质元素的含量，CO₂施肥时间延长，降幅增大。CO₂施肥增强了黄瓜对矿质元素的吸收能力，使单株吸收总量显著增加，且施肥时间越长，吸收数量越多。因此，在CO₂施肥的同时应增加矿质营养的供给。     

模拟CCS技术CO2泄露对C4作物种子萌发的影响

模拟CCS技术CO₂泄露对C₄作物种子萌发的影响,以期为CCS技术CO₂泄露后可能产生的环境影响提供基础性资料。利用CO₂人工气候箱,模拟CCS技术CO₂泄露产生的高浓度CO₂环境,研究在CO₂分别为正常大气CO₂浓度(对照组),10000,20000,40000,80000 mg/kg时,对玉米、高粱、谷子、糜子4种C₄作物发芽率、发芽势以及平均发芽天数的影响。高浓度CO₂对玉米发芽率无明显影响,而高粱、谷子和糜子分别在10000,20000, 20000 mg/kg时发芽率达到最高值;高浓度CO₂对玉米发芽势亦无明显影响,而高粱、谷子和糜子均在20000 mg/kg时发芽势达到最高值;高浓度CO₂对4种C₄作物发芽天数均产生较小影响,其中,对糜子影响较为显著。在不同CO₂浓度范围内对C₄作物种子发芽率分别有促进和抑制作用,促进和抑制作用不是很显著,其中,促进范围1%~5%,抑制范围1%~4%;高浓度CO₂对C₄作物种子发芽势有比较显著的促进作用,较对照组,发芽势的促进范围为9%~16%;高浓度CO₂对4种C₄作物发芽天数均产生较小影响。     

CO2浓度增加对作物影响的实验研究进展

简要综述了近10年来国内外有关CO₂增加对作物生长影响的研究方法、实验装置和实验结果。CO₂增加促进了作物光合、抑制蒸腾、提高了水分利用率,有利于作物生长发育、干物质积累和产量形成。就总体而言,C₃比C₄作物对CO₂增加的反应更为敏感。     

无糖培养条件下大型组培箱内CO2变化规律及对组培苗的影响

该文采用中国农业大学农业部设施农业生物环境工程重点开放实验室研制的设有组培微环境实时监控系统的大型组培箱，分别对矮牵牛、菊花和番茄组培苗移栽后箱体内CO₂浓度的变化规律及不同CO₂增施浓度对无糖组培苗生长的影响进行了研究。试验表明：移栽后的当天，组培箱内的CO₂浓度便开始下降，第2 d下降速度明显加快，均降至100 μL/L以下。在移栽后的第4～5 d，箱体内CO₂浓度下降到35 μL/L左右后便不再下降，一直在30～40 μL/L之间波动。因此得出：无糖培养在组培苗移栽后的第2 d就应增施CO₂，否则会直接影响组培苗的生长。在不同CO₂增施浓度试验中，当光照度控制在80 μmol/(m²·s)时，CO₂浓度为(650±50)μL/L时培养出的组培苗生长状况最好。     

水培条件下CO2与NH+4/NO-3配比对番茄幼苗生育的影响

升高CO₂浓度能够促进作物的光合作用，提高作物的生物量和产量，但关于CO₂与NH⁺₄/NO^-₃比及其交互作用对作物影响的研究较少，为探索番茄幼苗生长发育对CO₂浓度升高的响应是否对NH⁺₄/NO^-₃配比有较强的依赖关系，本试验在营养液栽培条件下，以番茄(Lycopersicun esculentum Mill)为试材，研究正常大气CO₂浓度(360 μL/L)和倍增CO₂浓度(720 μL/L)与不同NH⁺₄/NO^-₃配比的交互作用对番茄幼苗生长的影响。结果表明：CO₂浓度升高提高了低NH⁺₄/NO^-₃比例处理中番茄叶片的光合速率和水分利用率，提高幅度随NH⁺₄/NO^-₃比例的降低而增强，光合速率增强最大达55%。在同一CO₂浓度处理下净光合速率与水分利用率均随NH⁺₄/NO^-₃比例的增加而显著降低。这说明CO₂浓度升高对番茄幼苗生长发育的促进作用随NH⁺₄/NO^-₃比例的降低而提高，但并没有减弱全NH⁺₄-N处理中番茄幼苗的受毒害作用。综上所述，CO₂浓度升高能提高植物生产的节水能力和水分生产力；水培条件下，NO^-₃-N是最适合番茄幼苗生长发育的氮源，其它NH⁺₄/NO^-₃比例对番茄幼苗的生长发育有一定的抑制作用，仅以NH⁺₄-N作氮源则番茄幼苗很难生长。     

CO2气调防治储粮害虫试验研究

利用自行设计的试验装置，充入CO₂气体使储粮害虫(谷蠹与米象)窒息死亡，以达到杀灭粮食害虫的目的。试验分为两个部分，一是在实验室里进行，试验温度分别在15～18℃和23～28℃；试验的CO₂气体浓度分别控制在25%、30%、35%、40%、45%、50%、55%和60%左右；试验时间分别为24、48、72、96、120、168 h。通过多次试验，找出了实验室试验的最佳参数：温度为(25±3)℃；CO₂气体浓度为25%～35%；谷蠹杀虫保持时间为72 h以上；米象杀虫保持时间为48 h。二是在实验仓进行试验，将传感器通过管道分别布置在仓的各个部位，并每隔12～24 h，测取温、湿度等。 实验仓的试验验证了实验室的试验结果，但杀虫的持续时间为10 d以上，研究成果为实仓应用CO₂气调防治储粮害虫提供了可靠的依据。     

大气CO2倍增对水稻生长和发育的影响

矮香糯水稻(Oryza sativa L, )插身后生长在大气（350ppm CO₂）和CO₂倍增（700 ppm CO₂）的开顶式培养室中，结果显示，在CO₂倍增的条件下，矮香糯生长旺盛，根系发达，根系干重增加23%，株高增加12%，每穗结实率增加29%，每株籽粒干重增加41%。本文对目前有关这方面的研究现状进行了讨论。     

超临界CO2萃取万寿菊花中叶黄素的研究

采用超临界CO₂萃取技术,研究了从万寿菊花中萃取叶黄素的工艺条件。对影响超临界CO₂萃取叶黄素的各种因素,包括分离参数、原料含水率、粉碎粒径，超临界萃取温度、压力、流速、时间等因素进行了考察,得到较佳的萃取工艺条件为:原料含水率10.92％，粒径40目，萃取温度60℃，压力30 MPa，CO₂流速15 L/h，分离釜Ⅰ温度40℃，压力6 MPa，分离釜Ⅱ温度20℃，时间为6 h。     

畜菜互补生态系统综合研究(Ⅰ)——CO2动态模拟及畜菜配比选择

现有畜菜互补生,系统畜菜配比差异极大,致使CO₂浓度过高或过低,影响CO₂气体施肥效果。在设有内部CO₂通风传输装置且温室CO₂均匀分布的条件下,建立了系统CO₂质量平衡数学模型,编制并验证了CO₂日变化动态模拟的计算机程序。利用该程序,以家畜给温室提供适宜的CO₂浓度为依据,以番茄与育肥猪为例,对沈阳地区主要CO₂施肥期12月～3月的畜菜配比进行了优化选择,为该生态系统的建设及管理提供了一定的依据。     

产CO2气肥残余物对番茄产量和品质的影响

为通过田间试验,研究和比较了商品有机肥和产CO_2气肥残余物对番茄生长和品质的影响。试验结果表明,施用商品有机肥和产CO_2气肥残余物均可促进番茄产量的增加,分别较CK处理增加了24.02%和28.59%,但二者之间没有达到显著性差异;通过对各处理中番茄品质指标的结果分析,可以得知,产CO_2气肥残余物显著降底了番茄坏果率,比有机肥和CK处理分别降低了18.18%和33.33%。产CO_2气肥残余物促进了番茄可溶性糖和维生素C含量的提升。由此可知,产CO_2气肥残余物较商品有机肥,可以增加番茄产量、显著降低番茄果实坏果率并改善番茄果实的品质。     

畜菜互补生态系统综合研究(Ⅱ)——CO2分布状况及传输系统试验分析

通过试验测试揭示了自然扩散状态下的畜菜互补生态系统内温室中CO₂分布不均,存在着较大的浓度梯度以及畜菜配比不当等问题。设计并试验测试了塑料风管传输装置及兼有CO₂传输功能的地下热交换系统,两者对改善系统内的CO₂分布,提高蔬菜产量起到了明显作用。     

Relationship between soil CO2 concentrations and forest-floor CO2 effluxes

To better understand the biotic and abiotic factors that control soil CO₂ efflux, we compared seasonal and diurnal variations in simultaneously measured forest-floor CO₂ effluxes and soil CO₂ concentration profiles in a 54-year-old Douglas fir forest on the east coast of Vancouver Island. We used small solid-state infrared CO₂ sensors for long-term continuous real-time measurement of CO₂ concentrations at different depths, and measured half-hourly soil CO₂ effluxes with an automated non-steady-state chamber. We describe a simple steady-state method to measure CO₂ diffusivity in undisturbed soil cores. The method accounts for the CO₂ production in the soil and uses an analytical solution to the diffusion equation. The diffusivity was related to air-filled porosity by a power law function, which was independent of soil depth. CO₂ concentration at all depths increased with increase in soil temperature, likely due to a rise in CO₂ production, and with increase in soil water content due to decreased diffusivity or increased CO₂ production or both. It also increased with soil depth reaching almost 10 mmol mol⁻¹ at the 50-cm depth. Annually, soil CO₂ efflux was best described by an exponential function of soil temperature at the 5-cm depth, with the reference efflux at 10 °C (F₁₀) of 2.6 μmol m⁻² s⁻¹ and the Q₁₀ of 3.7. No evidence of displacement of CO₂-rich soil air with rain was observed.Effluxes calculated from soil CO₂ concentration gradients near the surface closely agreed with the measured effluxes. Calculations indicated that more than 75% of the soil CO₂ efflux originated in the top 20 cm soil. Calculated CO₂ production varied with soil temperature, soil water content and season, and when scaled to 10 °C also showed some diurnal variation. Soil CO₂ efflux and concentrations as well as soil temperature at the 5-cm depth varied in phase. Changes in CO₂ storage in the 0–50 cm soil layer were an order of magnitude smaller than measured effluxes. Soil CO₂ efflux was proportional to CO₂ concentration at the 50-cm depth with the slope determined by soil water content, which was consistent with a simple steady-state analytical model of diffusive transport of CO₂ in the soil. The latter proved successful in calculating effluxes during 2004.     

Flow-microcalorimetry measurements of aerobic and anaerobic soil microbial activity

Heat output can be used as an indicator of microbial activity and is usually measured in a microcalorimeter with closed ampoules. In long-term experiments particularly, interpretation of the data is hindered by the changing environment in the closed ampoules because of O₂ consumption and CO₂ enrichment. We used a combination of a flow-microcalorimeter and a gas chromatograph to measure the heat flux and CO₂ and N₂O production rates under controlled conditions. Simultaneous detection of the heat output and CO₂ emission allowed calculation of the calorimetric: CO₂ (Cal/CO₂) ratio. A mean ratio of-435 kJ mol^-1 CO₂ was detected in six different soils amended with glucose and incubated under aerobic conditions. This ratio indicated that CO₂ was the end-product of catabolism. In wet 10–12 mm soil aggregates of a gleyic vertisol amended with glucose, values of-285 kJ mol^-1 CO₂ under an aerobic and-141 kJ mol^-1 CO₂ under a N₂ atmosphere was determined. These findings indicated that fermentative metabolism occurred. The Cal/CO₂ ratio was not affected when enough NO _inf3 ^sup- was available and denitrification processes (N₂O production) were possible.     

Increased moisture and methanogenesis contribute to reduced methane oxidation in elevated CO2 soils

Awareness of global warming has stimulated research on environmental controls of soil methane (CH₄) consumption and the effects of increasing atmospheric carbon dioxide (CO₂) on the terrestrial CH₄ sink. In this study, factors impacting soil CH₄ consumption were investigated using laboratory incubations of soils collected at the Free Air Carbon Transfer and Storage I site in the Duke Forest, NC, where plots have been exposed to ambient (370 μL L⁻¹) or elevated (ambient + 200 μL L⁻¹) CO₂ since August 1996. Over 1 year, nearly 90% of the 360 incubations showed net CH₄ consumption, confirming that CH₄-oxidizing (methanotrophic) bacteria were active. Soil moisture was significantly (p < 0.01) higher in the 25–30 cm layer of elevated CO₂ soils over the length of the study, but soil moisture was equal between CO₂ treatments in shallower soils. The increased soil moisture corresponded to decreased net CH₄ oxidation, as elevated CO₂ soils also oxidized 70% less CH₄ at the 25–30 cm depth compared to ambient CO₂ soils, while CH₄ consumption was equal between treatments in shallower soils. Soil moisture content predicted (p < 0.05) CH₄ consumption in upper layers of ambient CO₂ soils, but this relationship was not significant in elevated CO₂ soils at any depth, suggesting that environmental factors in addition to moisture were influencing net CH₄ oxidation under elevated CO₂. More than 6% of the activity assays showed net CH₄ production, and of these, 80% contained soils from elevated CO₂ plots. In addition, more than 50% of the CH₄-producing flasks from elevated CO₂ sites contained deeper (25–30 cm) soils. These results indicate that subsurface (25 cm+) CH₄ production contributes to decreased net CH₄ consumption under elevated CO₂ in otherwise aerobic soils.     

A new technique to measure soil CO2 efflux at constant CO2 concentration

A new principle for measuring soil CO₂ efflux at constant ambient concentration is introduced. The measuring principle relies on the continuous absorption of CO₂ within the system to achieve a constant CO₂ concentration inside the soil chamber at ambient level, thus balancing the amount of CO₂ entering the soil chamber by diffusion from the soil. We report results that show reliable soil CO₂ efflux measurements with the new system. The novel measuring principle does not disturb the natural gradient of CO₂ within the soil, while allowing for continuous capture of the CO₂ released from the soil. It therefore holds great potential for application in simultaneous measurements of soil CO₂ efflux and its δ¹³C, since both variables show sensitivity to a distortion of the soil CO₂ profile commonly found in conventional chamber techniques.     

用超临界CO2脱除绿茶浓缩液中咖啡碱的工艺研究

对绿茶浓缩液中咖啡碱的超临界CO₂萃取工艺进行了研究，通过4因素正交试验探讨了浓缩液的浓度、操作压强、操作温度、萃取时间对咖啡碱脱除率的影响。结果表明，超临界CO₂萃取技术可以有效地脱除绿茶浓缩液中大部分的咖啡碱，在此基础上完成了用超临界CO₂脱除绿茶浓缩液中咖啡碱的连续作业试验，从而获得了加工脱咖啡碱绿茶浓缩液或速溶绿茶的新工艺。     

压力、温度对穿心莲内酯超临界CO2萃取-结晶的影响

以穿心莲浸膏为原料，进行了穿心莲内酯的超临界CO₂萃取结晶分离纯化。考察了单因素参数压力、温度对穿心莲内酯纯度、结晶量等的影响。结果表明：超临界CO₂萃取结晶穿心莲内酯的纯度在结晶板上呈梯度分布；在25 MPa以下，压力升高，结晶板上部晶体纯度升高，而结晶量先增后减；在结晶板下部穿心莲内酯的纯度和结晶量都是先升高后降低；温度在一定范围内能提高晶体纯度，且有利于缩短萃取结晶时间。     

不同管理措施对滨海盐渍农田土壤CO2排放及碳平衡的影响

为探讨不同管理措施对滨海盐渍农田碳平衡的影响,本文通过玉米–小麦轮作试验,研究农田土壤的CO_2释放规律,及其农田碳收支状况。试验设计6个处理:1常规对照(CK);2有机肥常量(OF);3氮肥增施(NF);4秸秆还田(S);5有机肥加秸秆(OF+S);6免耕(NT)。研究表明,秸秆还田和有机肥的施用增加了土壤呼吸的强度,而免耕处理的CO_2平均释放量最低,不同处理下土壤呼吸总体表现为OF+SSOMNFCKNT。各处理土壤有机碳含量随着作物的收获逐渐升高,其中OF与NT增加最多,而增施氮肥处理并没有显著提高土壤的有机碳水平。各处理间的有机碳含量没有显著性差异。在两季作物种植结束后,各处理的碳输入均高于碳输出,均为碳净输入,表现出较强的碳汇特征。秸秆还田和单施有机肥的碳净输入均显著高于对照,可有效减缓因农田土壤CO_2排放而造成的全球气候变化问题。