On-line analysis of reactive VOCs from urban lawn mowing

We measured the release of volatile organic compounds (VOCs) resulting from lawn mowing during continuous ambient air measurements in July and August 1998 in the outskirts of Innsbruck, Austria. These measurements were made with a proton-transfer-reaction mass spectrometry system, which allowed simultaneous, on-line monitoring of VOCs in the pptv range. We observed the emission of C6 wound compounds, including (Z)-3-hexenal, (E)-2-hexenal, hexenol plus hexanal, and acetaldehyde immediately following lawn mowing, and a rise in background levels of C6 wound compounds that lasted for several hours. Peak levels of biogenic VOCs following mowing were in the same concentration range (20-60 ppbv) as those originating from combustion engines of lawn mowers, and integrated biogenic emissions were much greater in the drying grass clippings. Additional emissions of acetone and other VOCs resulted from rainfall on these clippings. Since the estimated atmospheric chemical reactivity of VOCs resulting from lawn mowing is of the same order of magnitude as unburned hydrocarbons released during the mowing by gasoline-powered lawn mowers, these biogenic VOCs should be considered in urban air-quality control strategies.     

Research on New Technology of Fiber Flax Harvesting

Modifications of combine harvester were introduced. Flax harvesting with the modified combine harvester following the dessication with Roundup did not affect the yield and weight of flax seeds when compared to the conventional pulling harvesting. A new method lead to a reduction in the yield of homomorphic fiber but losses depend on the cutting height and with the normal plant heigh (over 700 mm) and stubble height below 80 mm could be reduced to less than 10%. Flax harvesting by mowing can reduce the total labor costs by 30% and the labor costs of harvesting by more than 42%. Mowing of fiber flax fiber can significantly reduce and simplify the entire production technology.     

Occurrence and mass balance of isoflavones on an experimental grassland field

Isoflavones and coumestrol (COU) are estrogenic compounds that are naturally produced by plants (e.g., red clover, soybeans). Although these compounds have been extensively studied in food and feed, only little is known about their environmental fate. Therefore, we investigated the occurrence of isoflavones (formononetin, daidzein, equol, biochanin A, and genistein) and COU over 3.5 years in red clover, manure, and soil of a grassland field with and without manure application, as well as their emission via drainage water. Isoflavones were regularly quantified in plant (≤ 15 × 10(6) ng/g(dry weight (dw))), manure (≤ 230 × 10(3) ng/g(dw)), soil (≤ 3.4 × 10(3) ng/g(dw)), and drainage water samples (≤ 3.6 × 10(3) ng/L). In contrast, COU was observed only in manure and soil. Cumulative isoflavone loads emitted via drainage water were around 0.2 × 10(-3) kg/ha/y, which is very little compared to the amounts present in red clover (105-220 kg/ha/y), manure (0.5-1.0 kg/ha/y), and soil (0.1-5.1 kg/ha/y). Under good agricultural practice, no additional emission of isoflavones into drainage water was observed after manure application. With calculated 17β-estradiol equivalents up to 0.46 ng/L in drainage water, isoflavones can constitute a dominant and ecotoxicological relevant portion of the total estrogenicity in small rural river catchments.     

XAS speciation of arsenic in a hyper-accumulating fern

The coordination environment and the redox speciation of arsenic in a newly discovered arsenic hyper-accumulating fern (Pteris vittata L) were investigated by X-ray absorption spectroscopy. This method allowed us to probe arsenic directly, i.e., with minimal sample preparation. The results indicate that arsenic is predominantly accumulated as As(III) in the leaves. XANES and EXAFS results show that As(III) in the leaves is primarily present as aqueous arsenite species. The plant actively maintains arsenic in this reduced oxidation state, because after sample collection and subsequent aging and drying of the plant material, As(III) is gradually oxidized to As(V). We think that these arsenite species are sequestered in vacuoles. At extremely high As concentrations (ca. 1% As per dry weight) arsenic in the fern leaves is coordinated to a significant degree by sulfur in addition to oxygen. This spectral signature indicates that thiol-rich compounds are implicated in the biochemical transformations of arsenic within the plant.     

Carotenoid content and composition in rose hips (Rosa spp.) during ripening,determination of suitable maturity marker and implications for health promoting food products

Carotenoids are important antioxidants and valuable bioactive compounds contributing to the health benefits of different foods, and rose hips are known for high bioactive content. This study investigated the content of carotenoids and chlorophylls in hips from four rose species during the ripening period. Carotenoid content varied greatly between harvesting times, although species and year, and interactions between factors, also played an important role. Some carotenoids were identified only in hips of specific rose species. Some of the investigated compounds decreased (chlorophyll a) or increased (lycopene) consistently over the ripening period and could therefore be useful as maturity markers. An optimal content of total or specific carotenoids, e.g. for food products containing rose hips, might be obtained by proper choice of harvesting time and rose species.     

Comparing air dispersion model predictions with measured concentrations of VOCs in urban communities

Air concentrations of nine volatile organic compounds were measured over 48-h periods at 23 locations in three communities in the Minneapolis-St. Paul metropolitan area. Concentrations at the same times and locations were modeled using a standard regulatory air dispersion model (ISCST3). The goal of the study was to evaluate model performance by comparing predictions with measurements using linear regression and estimates of bias. The modeling, done with mobile and area source emissions resolved to the census tract level and characterized as model area sources, represents an improvement over large-scale airtoxics modeling analyses done to date. Despite the resolved spatial scale, the model did not fully capture the spatial resolution in concentrations in an area with a sharp gradient in emissions. In a census tract with a major highway at one end of the tract (i.e., uneven distribution of emissions within the tract), model predictions atthe opposite end of the tract overestimated measured concentrations. This shortcoming was seen for pollutants emitted mainly by mobile sources (benzene, ethylbenzene, toluene, and xylenes). We suggest that major highways would be better characterized as line sources. The model also failed to fully capture the temporal variability in concentrations, which was expected since the emissions inventory comprised annual average values. Based on our evaluation metrics, model performance was best for pollutants emitted mainly from mobile sources and poorest for pollutants emitted mainlyfrom area sources. Important sources of error appeared to be the source characterization (especially location) and emissions quantification. We expect that enhancements in the emissions inventory would give the greatest improvement in results. As anticipated for a Gaussian plume model, performance was dramatically better when compared to measurements that were not matched in space or time. Despite the limitations of our analysis, we found thatthe regulatory air dispersion model was generally able to predict space and time matched 48-h average ambient concentrations of VOC species within a factor of 2 on average, results that meet regulatory model acceptance criteria.     

延迟采收对晋中南地区梅鹿辄葡萄酒酚类物质的影响

以晋中南地区梅鹿辄葡萄为试材,探究延迟采收对葡萄酒基本理化指标、酚类物质、花色苷组分和非花色苷酚类物质的影响,以期为改善当地梅鹿辄葡萄酒品质提供理论依据。结果表明,延迟14 d后采收,梅鹿辄葡萄酒中的总花色素、总酚和各花色苷组分含量均有显著提高（P＜0.05）;延迟7 d后采收,可显著提高葡萄酒中的黄烷醇含量（P＜0.05）;但延迟采收对葡萄酒中的单宁含量有较显著的降低作用（P＜0.05）。因此,延迟14 d采收有利于提高葡萄酒酚类物质的含量,改善葡萄酒的质量。     

Delayed light emission as a means of quality evaluation of fruits and vegetables

DLE is probably produced by all fruits, vegetables, and plant materials undergoing photosynthesis. However, the intensity and duration of the emitted light vary widely depending upon many factors. Because of the strong dependence of DLE on the chlorophyll content, variation in the DLE can be expected among different varieties of the same product. Therefore, quality evaluation based on DLE measurements require careful selection of measuring criteria such as duration and intensity of illumination, dark period, and temperature. It is necessary to obtain precise values of DLE for a particular product under a set condition; and the measurement conditions should be carefully validated to establish a standard measuring criteria. In general, the quality evaluation of fruits and vegetables is based on three major aspects: maturity and/or ripeness evaluation, composition analysis, and internal and external defect detection. DLE measurements so far have focused mainly on maturity evaluation because of the definite relationship between the emitted light and chlorophyll concentration, which changes with maturity. It should be noted that chlorophyll alone is not sufficient; it is the complex of in situ chlorophyll and related compounds in plant materials that jointly contribute to the DLE. Composition of fruits such as sugar content has been related to DLE. Recently, DLE measurements have been applied to detect certain physiological stress responses and defects such as chilling injuries. However, these areas of research have not yet been fully explored. Further investigation relating to compositional quality and internal and external defects of fruits and vegetables with DLE measurement may offer solutions to certain complex quality evaluation problems. The duration of DLE after excitation involves a matter of at least several seconds. From a mechanical standpoint, this extended period of light emission offers a convenient time in which to separate excitation and measurement. However, the exponential decay necessitates very precise control of time between illumination and measurement. The broad activation spectrum permits wide choice and simple design of excitation sources. However, size, shape, and varietal variations of plant materials make uniform DLE measurements difficult. It is suggested that DLE measuring instruments be designed to make several measurements over the entire surface of the specimen. An average of such measurements would reduce the effect of surface nature and shape of the product. Reporting the DLE intensity per unit surface area of the product will eliminate the dependence of area of excitation on DLE.(ABSTRACT TRUNCATED AT 400 WORDS)     

Enhancement of Shortening Stability by Incorporation of Butteroil

Butteroil, sunflower oil, olive oil, and a blend containing equal portions of the three oils were used for potato frying and examined periodically for oxidative stability. Analysis included measurements of polymers, cyclic monomers, the change in dielectric constant and volatile compounds. The blend exhibited greater stability than expected on the basis of the data obtained from the individual oils. In one frying experiment, for example, the polymers and cyclic monomers formed in the blended oil after 37 hr were 0.6% and 0.2%, respectively, as compared to calculated values of 1.8% and OS%, respectively. The higher stability of the blended shortening against oxidation appeared to reflect the presence in butteroil of a protective agent or agents sufficient to protect other less stable oils.     

Photochemical modeling of the Ozark isoprene volcano: MEGAN, BEIS, and their impacts on air quality predictions

Biogenic volatile organic compounds (BVOCs) contribute substantially to atmospheric carbon, exerting influence on air quality and climate. Two widely used models, the Model of Emissions of Gases and Aerosols from Nature (MEGAN) and the Biogenic Emission Inventory System (BEIS) are employed to generate emissions for application in the CMAQ air quality model. Predictions of isoprene, monoterpenes, ozone, formaldehyde, and secondary organic carbon (SOC) are compared to surface and aloft measurements made during an intensive study in the Ozarks, a large isoprene emitting region. MEGAN and BEIS predict spatially similar emissions but magnitudes differ. The total VOC reactivity of the emissions, as developed for the CB05 gas-phase chemical mechanism, is a factor of 2 different between the models. Isoprene estimates by CMAQ-MEGAN are higher and more variable than surface and aloft measurements, whereas CMAQ-BEIS predictions are lower. CMAQ ozone predictions are similar and compare well with measurements using either MEGAN or BEIS. However, CMAQ-MEGAN overpredicts formaldehyde. CMAQ-BEIS SOC predictions are lower than observational estimates for every sample. CMAQ-MEGAN underpredicts SOC ～ 80% of the time, despite overprediction of precursor VOCs. CMAQ-MEGAN isoprene predictions improve when prognostically predicted solar radiation is replaced with the GEWEX satellite product. CMAQ-BEIS does not exhibit similar photosensitivity.     

组合体外与临床测试评价植物抗氧化剂抗老化功效

基于非动物测试理念,研究植物抗氧化剂复配后的皮肤抗老化功效。方法 体外培养HaCaT角质细胞,紫外线照射诱发氧化损伤模型,分别加入白藜芦醇、原花青素和二者复配物,用MTT比色法、荧光素标记法和ELISA法检测细胞活性、活性氧簇自由基(ROS)、超氧化物岐化酶(SOD)、细胞周期及细胞凋亡的变化。对含两种植物原料的眼霜配方进行鸡胚尿囊膜血管试验(CAMVA)和牛角膜混浊渗透试验(BCOP)的组合测试评价其眼刺激性。选择平均年龄40岁的女性志愿者25名,眼部连续使用该眼霜60 d,于使用产品的第0、30和60 d分别检测皮肤的水份、水份流失、弹性和肤色等皮肤老化相关指标。结果 白藜芦醇-原花青素复配的植物抗氧化剂可明显缓解紫外线造成的HaCaT细胞氧化损伤,SOD水平明显升高(P<0.001),ROS荧光强度、细胞凋亡率及S期细胞比例均明显降低(P<0.001),细胞修复作用强于单独作用。经过替代方法组合评价其安全性后进行临床志愿者测试,证明皮肤保湿、弹性和皮肤颜色等指标得到改善。结论 白藜芦醇和原花青素两种植物抗氧化剂复配使用可有效减少皮肤氧化应激和明显改善皮肤性能。     

围栏与不同放牧强度对东祁连山高寒草甸植被和土壤的影响--测试文章

在东祁连山高寒草地，对围栏7年和不同放牧强度的草地进行了物种数、地上生物量、地下生物量、土壤理化性质等研究。结果表明，围栏7年的高寒草地鲜草产量为425.8 g·m^-2，显著高于夏季中牧159.3 g·m^-2和夏季重牧91.0 g·m^-2，但与冬季轻牧、夏季轻牧差异不显著。围栏条件下的物种数为26.3种·16 m^-2，显著低于其他放牧条件下的物种数，但显著高于夏季重牧条件下的物种数23.0 种·16 m^-2；轻度或重度放牧都会使物种数减少，夏季中牧下的物种数最高（33.5 种·16 m^-2）。在0～10 cm的表层土壤中，围栏7年的草地根系生物量显著高于其他放牧强度。随着放牧强度的增加，根系生物量在0～10 cm土壤中呈下降趋势，在30～40 cm土壤中则表现为升高趋势。围栏7年的土壤容重低于其他放牧强度下的土壤容重，但差异不显著；夏季重牧的土壤容重显著高于围栏7年和其他放牧强度的土壤容重。随着放牧强度的增加，0～10 cm土壤碱解氮增加，围栏7年草地最低。围栏封育可有效改善和恢复草地植被，但不能长时间禁牧不进行放牧利用。合理的放牧能够维护高寒草甸草地生态系统功能、促进物种丰富度和土壤营养的均衡。     

New insights to the use of ethanol in automotive fuels: a stable isotopic tracer for fossil- and bio-fuel combustion inputs to the atmosphere

Ethanol is currently receiving increased attention because of its use as a biofuel or fuel additive and because of its influence on air quality. We used stable isotopic ratio measurements of (13)C/(12)C in ethanol emitted from vehicles and a small group of tropical plants to establish ethanol's δ(13)C end-member signatures. Ethanol emitted in exhaust is distinctly different from that emitted by tropical plants and can serve as a unique stable isotopic tracer for transportation-related inputs to the atmosphere. Ethanol's unique isotopic signature in fuel is related to corn, a C4 plant and the primary source of ethanol in the U.S. We estimated a kinetic isotope effect (KIE) for ethanol's oxidative loss in the atmosphere and used previous assumptions with respect to the fractionation that may occur during wet and dry deposition. A small number of interpretive model calculations were used for source apportionment of ethanol and to understand the associated effects resulting from atmospheric removal. The models incorporated our end-member signatures and ambient measurements of ethanol, known or estimated source strengths and removal magnitudes, and estimated KIEs associated with atmospheric removal processes for ethanol. We compared transportation-related ethanol signatures to those from biogenic sources and used a set of ambient measurements to apportion each source contribution in Miami, Florida-a moderately polluted, but well ventilated urban location.     

不同修剪高度对茶树稀土和氟铝含量及品质的研究

目的分析不同茶树修剪高度稀土(REE)、氟(F)、铝(Al)含量的高低,为阐明茶树高度和稀土F、Al含量在茶树中的积累特性机制提供一定的基础。方法采用ICP-MS测定茶叶中稀土和Al含量,氟离子电极法测定茶叶中F含量,应用Microsoft Excel软件和SPSS19.0软件,采用使用新复极差法进行显著性分析,Pearson相关性分析茶树稀土的含量和生化成分差异及其相关性。结果经过定型修剪后,表现为随着茶树修剪高度的降低,稀土和Al含量呈逐渐增加的趋势,修剪高度最低的20 cm稀土含量(0.36 mg/kg)显著高于传统树冠高度60 cm(0.12 mg/kg),F含量则在40 cm修剪高度时达到最高;儿茶素总量和茶多酚含量则有随着茶树高度的增加而降低,成品茶中稀土、F、Al含量大致和定型修剪后的鲜叶一致。稀土含量和F、Al含量之间达到了极显著相关,稀土、Al含量与茶叶品质成分中的酯型儿茶素也呈显著的正相关。结论本研究发现不同修剪高度对茶树的稀土、F、Al元素含量和品质成分均产生了一定的影响,但影响程度不同,随着修剪高度的降低,茶树传统树冠下稀土、F、Al元素的含量均会低于现阶段采用的矮树冠。     

Volatile metal species in coal combustion flue gas

Metals are released in effluents of most of combustion processes and are under intensive regulations. To improve our knowledge of combustion process and their resulting emission of metal to the atmosphere, we have developed an approach allowing usto distinguish between gaseous and particulate state of the elements emitted. This study was conducted on the emission of volatile metallic species emitted from a coal combustion plant where low/medium volatile coal (high-grade ash) was burnt. The occurrence of volatile metal species emission was investigated by cryofocusing sampling procedure and detection using low-temperature packed-column gas chromatography coupled with inductively coupled plasma-mass spectrometry as multielement detector (LT-GC/ICP-MS). Samples were collected in the stack through the routine heated sampling line of the plant downstream from the electrostatic precipitator. The gaseous samples were trapped with a cryogenic device and analyzed by LT-GC/ICP-MS. During the combustion process, seven volatile metal species were detected: three for Se, one for Sn, two for Hg, and one for Cu. Thermodynamic calculations and experimental metal species spiking experiments suggest that the following volatile metal species are present in the flue gas during the combustion process: COSe, CSSe, CSe2, SeCl2, Hg0, HgCl2, CuO-CuSO4 or CuSO4 x H2O, and SnO2 or SnCl2. The quantification of volatile species was compared to results traditionally obtained by standardized impinger-based sampling and analysis techniques recommended for flue gas combustion characterization. Results showed that concentrations obtained with the standard impinger approach are at least 10 times higher than obtained with cryogenic sampling, suggesting the trapping microaerosols in the traditional methods. Total metal concentrations in particles are also reported and discussed.     

Origin of nitrogen in reforested lignite-rich mine soils revealed by stable isotope analysis

Restoration of the nitrogen cycle is an important step in the recovery of an ecosystem after mining. Carbon and nitrogen in rehabilitated lignite containing mine soils can be derived from plant material as well as from lignite inherent to the parent substrate. We assessed the use elemental and stable carbon and nitrogen isotope measurements to trace the orgin of soil nitrogen and applied these techniques to elucidate the origin of mineral N in the soil and the soil solution. The conceptual approach of this study included physical fractionation in addition to sampling of vegetation and soil from a lignite-containing mine site rehabilitated in 1985 with Pinus Nigra. We studied the elemental and isotopic composition of bulk samples as well as isolated fractions and soil solution. Our data indicate that the stable carbon and nitrogen isotopic composition of the soil samples are the result of mixing between plant material and substrate inherent lignite. delta15N isotopes may be used as indicators of nitrogen contribution from plants to solid samples as well as soil solution. N-isotope composition of ammonia shows low spatial and interannual variability, despite strong concentration changes. Plant-derived nitrogen contributes in higher amounts to the soil solution compared to the bulk mineral soil.     

Odour gradients and patterns in volatile emission of different plant parts and developing fruits of grapefruit (Citrus paradisi L.)

The volatiles spontaneously emitted in vivo by different plant parts of grapefruit (Citrus paradisi Macf., Rutaceae) were collected by solid phase micro-extraction (SPME) during the whole vegetative cycle of the plant and characterised by GC–MS to verify their involvement in entomophilous pollination, a controversial topic in the biology of this species. Furthermore, the essential oils obtained by expression of the pericarp from unripe and ripe fruits were studied. Altogether 127 compounds were identified, accounting from 82.1% to 99.9% of the whole volatiles. The main constituents detected were mono- and sesquiterpenes, with limonene (0.5–95.2%), linalool (0.2–52.5%), sabinene (0.5–42.5%), myrcene (0.2–15.4%), and β-caryophyllene (0.3–41.0%) as the most represented ones.     

EFFECT OF CONTROLLED CONDITIONS DURING DEEP BED FERMENTATION AND DRYING ON ROOIBOS TEA (ASPALATHUS LINEARIS) QUALITY

Small-scale processing of rooibos tea was achieved under controlled conditions of bruising, fermentation and drying. The effects of aeration, fermentation time, fermentation temperature and drying method on rooibos quality were investigated, using plant material that was stored at −30C after harvesting and comminution. Adequate aeration significantly improved rooibos quality. Overall quality improved significantly with increasing fermentation time, mainly due to an improvement in taste. Fermentation temperature did not affect quality significantly. Freezing of the plant material before processing was detrimental to quality, resulting in some instances in a Standard grade infusion with a grassy aroma and an astringent taste that is indicative of under-fermented rooibos. Choice grade rooibos with a flat, "thin" taste and a poorly developed sweet aroma was obtained in a few cases. The drying method (deep bed versus thin layer) did not affect overall quality significantly.     

Aerobic methane emission from plants in the Inner Mongolia steppe

Traditionally, methane (CH4) emission from terrestrial plants is thought to originate from belowground microbial metabolism under anaerobic conditions, with subsequent transport to the atmosphere through stems. However, a recent study reported aerobic CH4 emission from plants by an unrecognized process, a result that has since been questioned. We investigated CH4 emissions under aerobic conditions from aboveground tissues of 44 species indigenous to the temperate Inner Mongolia steppe. Ten herbaceous hydrophytes (wetland-adapted plants) were examined, two of which--Glyceria spiculosa and Scirpus yagara--emitted CH4 from stems but not from detached leaves. Of 34 xerophytes (arid-adapted plants) examined, 7 out of 9 shrub species emitted CH4 from detached leaves but not stems, whereas none of 25 herbaceous xerophytes emitted CH4. The herbaceous hydrophyte, S. yagara, emitted highly 13C-depleted CH4, suggesting a microbial origin. Achillea frigida exhibited the highest CH4 emission rates among the shrubs and continuously emitted relatively 13C-enriched CH4 from detached leaves, indicating that CH4 was derived directly from plant tissues under aerobic conditions. Because woody species are relatively rare in the Inner Mongolia steppe, aerobic, plant-derived CH4 emission is probably negligible in this region. Our results may imply a larger role for aerobic CH4 production in upland ecosystems dominated by woody species or in ecosystems where woody encroachment is occurring as a result of global change.     

Direct evidence of atmospheric secondary organic aerosol formation in forest atmosphere through heteromolecular nucleation

Atmospheric aerosols play a central role in climate and atmospheric chemistry. Organic matter frequently composes aerosol major fraction over continental areas. Reactions of natural volatile organic compounds, with atmospheric oxidants, are a key formation pathway of fine particles. The gas and particle atmospheric concentration of organic compounds directly emitted from conifer leaf epicuticular wax and of those formed through the photooxidation of alpha- and beta-pinene were simultaneously collected and measured in a conifer forest by using elaborated sampling and GC/ MS techniques. The saturation concentrations of acidic and carbonyl photooxidation products were estimated, by taking into consideration primary gas- and particle-phase organic species. Primary organic aerosol components represented an important fraction of the atmospheric gas-phase organic content Consequently, saturation concentrations of photooxidation products have been lowered facilitating new particle formation between molecules of photooxidation products and semi-volatile organic compounds. From the measured concentrations of the above-mentioned compounds, saturation concentrations (Csat,i) of alpha- and beta-pinene photooxidation products were calculated for nonideal conditions using a previously developed absorptive model. The results of these calculations indicated that primarily emitted organic species and ambient temperature play a crucial role in secondary organic aerosol formation.