冬麦田臭氧干沉降过程的观测

地表臭氧作为近地层最主要的大气污染物之一,其不断上升的浓度及其对粮食作物的影响受到越来越多的关注.本研究利用微气象学观测方法,探明自然条件下冬麦田的臭氧沉降过程,分析了影响臭氧沉降过程的环境因子.结果表明: 观测期内(小麦生长旺期)臭氧通量均值为-0.35 μg·m^-2·s^-1(负号表示沉降方向指向地面),臭氧沉降平均速率为0.55 cm·s^-1,空气动力学阻力均值为30 s·m^-1,粘性副层阻力均值为257 s·m^-1,冠层阻力均值为163 s·m^-1,且均存在明显的日变化趋势.臭氧沉降阻力大小受摩擦速度、太阳辐射强度、温度和相对湿度等因素的影响.     

臭氧对微生物杀菌作用的初步研究

以稀释平板计数法 ,测定了臭氧对水体和空气环境的消毒杀菌作用。结果表明 :随着臭氧浓度 (时间 )的增加 ,对各类微生物杀灭率明显上升 ,除了芽孢杆菌外 ,杀灭率可以达到 1 0 0 %。     

Relating Ozone Uptake in Forest Trees to Risk Assessment

This paper reviews the importance of ozone uptake through plant stomata in understanding plant response to ozone and discusses challenges in quantifying ozone uptake in forest trees. Uncertainties in spatial and temporal scaling of ozone uptake from the leaf to the landscape level, insufficient monitoring of ozone in forested areas, and tremendous variability in the composition and structure of forest ecosystems of the United States prevent the current use of ozone uptake in large-scale risk assessments and regulatory decisions.     

Impacts of ozone on Plantago major: apoplastic and symplastic antioxidant status

The aim of this work was to examine the correspondence between apoplastic/symplastic antioxidant status and previously reported plant age-related shifts in the ozone (O₃) resistance of Plantago major L. Seed-grown plants were fumigated in duplicate controlled environment chambers with charcoal/Purafil®-filtered air (CFA) or CFA plus 70 nmol mol⁻¹ O₃ for 7 h d⁻¹ over a 42 d period. Measurements of stomatal conductance and antioxidants were made after 14, 28 and 42 d fumigation, on leaves at an equivalent stage of development (youngest fully expanded leaf, measured c . 9 d after emergence). Ozone exposure resulted in a similar decline in stomatal conductance across plant ages, indicating that increases in O₃ resistance with plant age were mediated through changes in the tolerance of leaf tissue rather than enhanced pollutant exclusion. Leaf apoplastic washing fluid was found to contain 'unspecific' peroxidase, ascorbate peroxidase, superoxide dismutase and ascorbate, but not glutathione and the enzymes required to facilitate the regeneration of ascorbate from its oxidized forms. A weak induction in the activity of certain symplastic antioxidants was found after 14 d O₃ fumigation, despite a lack of visible symptoms of injury, but shifts in symplastic antioxidant enzyme activity were not consistent with previously observed increases in resistance to O₃ with plant age. By contrast, changes in 'unspecific' peroxidase activity and in the small pool of ascorbate in the leaf apoplast were found to accompany age-related shifts in O₃ resistance. It is concluded that constituents of the leaf apoplast may constitute a potentially important front line defence against O₃.     

钙对臭氧伤害小麦的防护作用

春小麦分别用0、1‰、3‰、5‰浓度的CaCl_2溶液浸种及培养,9天后,用0.3—0.7ppm浓度的臭氧(O_3)对幼苗熏气0、4、8、12h,观测到来经Ca~(2+)处理材料的叶片,其外渗液紫外吸收值和电导率随O_3处理时间延长都有不同程度的升高,而叶内可溶性糖和叶绿素含量都明显降低,经过3‰Ca~(2+)处理O_3熏气4—12h的材料,其外渗液紫外吸值、电导率、外渗糖、蒸腾强度都低于对照,其叶内可溶性糖及叶绿素含量均高于对照,证收明在一定O_3浓度范围内,3‰CaCl_2对O_3侵害小麦有明显的防护作用。     

臭氧浓度升高对银杏光合作用的影响

在臭氧浓度升高条件下,采用开顶箱(OTC)方法研究了臭氧浓度升高对沈阳市主要绿化树种银杏光合生理特性的影响.结果表明,与对照相比,高浓度(80±8 nmol·mol-1)臭氧处理下,银杏叶片净光合速率显著降低.处理50 d时,降低幅度为33.90%(P＜0.01),类胡萝卜素含量显著增加(P＜0.05);叶绿素a、叶绿素b与叶绿素(a b)含量变化复杂,叶绿素a/b值则先降低后升高;可溶性糖含量无明显变化,而淀粉含量则随着处理时间的延长显著降低;可溶性蛋白含量低于对照,并随着处理时间延长下降幅度增大;叶片中丙二醛含量随着处理时间显著增加.处理80 d时,丙二醛含量增加了79.53%.光合作用的下降与叶绿素的变化无关,主要与膜脂过氧化有关.光合作用的下降导致了可溶性蛋白质和淀粉的减少,并最终导致生长缓慢.     

A Historical Overview of the Ozone Exposure Problem

Ozone can be found in essentially all locations in the troposphere. Too much exposure of vegetation and humans to this potent oxidizing gas can prove toxic. Reports of human toxicity to ozone first appeared in the 1800's from accidental occupational exposures when ozone was first discovered. Ozone was recognized as damaging field vegetation with a report of altered leaf morphology in grapes in the 1950s. Ozone is the major oxidant component in photochemical smog, and is produced by reactions of volatile organic compounds and oxides of nitrogen with sunlight present. Soon after the inception of the U.S. Environmental Protection Agency (US EPA), the Agency set a general “oxidants” standard (which included ozone) in 1971. A primary standard was created to protect human health and a secondary standard to protect against agricultural losses, ecological damage, and other losses. Ozone concentrations have decreased steadily over the last two decades in some areas of the U.S., but have increased in other areas. Several aspects of ozone exposure need further characterization, including better determination of rural concentrations and the relationship of outdoor to indoor concentrations. Ozone is one of the six criteria air pollutants requiring a formal reexamination of the new findings of effects on health and vegetation on a periodic basis, a process that leads to the publication of an US EPA criteria document. As a result of further study concerning ozone effects, significant changes were made to pollution standards in 1979 and 1997. This toxicant has remained a major air pollutant of concern in the U.S. despite regulation and intense study over several decades.     

臭氧对农作物影响的模型

对流层臭氧(O3)浓度增加对作物的不利影响已受到广泛关注,臭氧模型研究自然已成为该领域的热点之一。建立有效的模型对臭氧造成的作物产量损失进行评估和预测,能为中国臭氧污染的控制和农业安全提供科学依据。根据模型与作物生长关系的紧密程度,可将其分为统计模型和机理模型2大类。本文依据模型的研究进程,依次阐述了浓度响应、剂量响应、通量响应3个统计模型;重点分析国内外影响较大的CLASS、Martin和AFRCWHEAT2-O33个机理模型;指出各模型的局限性,并对相关研究发展方向的可行性措施进行讨论。     

臭氧对无土栽培营养液的消毒作用研究

采用稀释平板法和MPN法,测定了臭氧对无土栽培营养液的消毒杀菌作用。结果表明,随着臭氧浓度(时间)的增加,对微生物杀灭率明显上升;连续处理20min,可杀灭90%以上的细菌、真菌和藻类;臭氧间歇曝气消毒营养液,有效控制微生物的滋生,对莴苣根系无不良影响,增加产量36.8%。     

Risk Assessment of Tropospheric Ozone: Human Health,Natural Resources,and Ecology

Ozone is an unusual trace gas in the atmosphere, presenting a challenge for risk assessors and risk managers. The challenge can be traced to the gas’ complex chemistry in the atmosphere (exposure), toxicology in biological systems (response), and the fledgling enterprise of risk assessment for widely distributed, highly reactive pollutants. This paper addresses the (i) co-evolution of the scientific data underlying ozone risk assessment on human health, natural resources (crops and managed forests), and unmanaged ecosystems, (ii) similarities and differences in risk assessment among these receptors, and (iii) utility of indicators in risk assessment. The scientific community has developed a sound database to underpin the ozone risk assessment, although the breadth and depth differ markedly among the three receptors. There are similarities in ozone risk assessment among human health, natural resources, and ecology, including features of exposure (e.g., temporal variation), response of plants and humans (e.g., sensitive cohorts), and integration of exposure and response (e.g., importance of peak and cumulative exposures). Equally important are the notable differences, and the more prominent are scaling of exposure-response relationships, air quality monitoring, economic valuation, and models to complement more traditional experimental approaches. Of the three receptors, the status of indicators for conducting ecological ozone risk assessment is the weakest.     

Effect of Hyper-Osmotic Stress On Alanine Content of Leishmania Major Promastigotes

ABSTRACT Earlier studies showed that Leishmania major promastigotes are sensitive to osmotic conditions. A reduction in osmolality caused the cells to shorten and to rapidly release most of their large internal pool of alanine. In this study some effects of hyper-osmotic stress were examined. an increase in osmolality of the culture medium from 308 to 625 mOsm/kg caused only a small decrease in growth rate. When cells grown in the usual culture medium (308 mOsm/kg) were washed, resuspended in iso-osmotic buffer, and subjected to acute hyper-osmotic stress by addition of mannitol, the alanine content increased even in the absence of exogenous substrate. Promastigotes, depleted of alanine by a 5-min exposure to hypo-osmotic conditions, also synthesized alanine when resuspended in iso-osmotic buffer. Washed cells resuspended in iso-osmotic buffer consume their internal pool of alanine under aerobic conditions, Rates of consumption decreased on addition of mannitol, becoming zero at about 440 mOsm/kg. At higher osmolalities, alanine synthesis occurred. to estimate whether proteolysis could account for alanine synthesis in the absence of exogenous substrate, cells that had been grown with [1-¹⁴C]leucine were washed and resuspended under hypo-, iso-, and hyper-osmotic conditions and the amounts of ¹⁴CO₂ and ¹⁴C-labelled peptides released in 1 h were measured. Little proteolysis occurred under these conditions, but the possibility that proteolysis was the source of the alanine increase, observed in response to hyper-osmotic stress, cannot be ruled out.     

山楂和山楂叶的氨基酸分析

本文用835-50型氨基酸自动分析仪测定了山楂和山楂叶中17种氨基酸的含量。结果表明,山楂叶中氨基酸的总含量高达10.3％,山楂中约含2.4％。     

Suitability of a combined stomatal conductance and photosynthesis model for calculation of leaf-level ozone fluxes

Currently, the most important source of uncertainty in stomatal ozone flux ( FO3) modelling is the stomatal conductance ( gst) factor. Hence FO3 model accuracy will strongly depend on the gst model being implemented. In this study the recently developed semi-empirical Gst model of Dewar was coupled to the widely known biochemical photosynthesis ( An) model of Farquhar. The Gst performance of this model combination was evaluated with a 4-month time series of beech ( Fagus sylvatica L.) measurements. The Gst model was hereto optimized in two steps to a 4-day and a 8-day period. A comparison between the modelled and measured gst to O(3) (gstO3) revealed a rather good overall performance (R(2)=0.77). Errors between the model combination and the measurements are thought to be largely caused by a moderate performance of the AN model, due to poor parameterization. Two 2-day periods with distinctly differing soil and meteorological conditions were chosen to give a picture of the daily gst performance. Although instant relative differences between modelled and measured gstO3 are sometimes high, the model combination is able to simulate the rough daily courses of gstO3 and hence FO3 reasonably well. Further improvement on full parameterization of the gst model and a well-parameterized An model to be linked to are needed to draw founded conclusions about its performance. Future efforts hereto are certainly justified since the model's mechanistic nature makes it a tool able to model gst variation in space and time, O(3) effects on gst, and effective FO3.     

大车前与平车前营养器官的比较解剖学研究

利用光学显微镜和石蜡切片技术对生长在盐碱地的大车前和平车前的营养器官进行了比较解剖学研究。结果表明二者的解剖结构存在差异:平车前根的木栓层较大车前的狭窄,栓内层细胞层数较少;平车前叶表皮的细胞角质膜较薄,孔下室较小,构成维管束鞘的薄壁细胞较大车前小,束鞘细胞两层。二者都具有适应盐渍环境的结构特征:营养器官中通气组织发达;根结构中薄壁组织和木栓发达;叶表皮角质层发达。     

陆地生态系统臭氧通量观测和气孔吸收估算研究进展

近地面大气中臭氧(O3)对植物生长发育和产量会产生不良影响。工业和交通排放的增加使得全球地面O3浓度逐年增加,不断升高的O3浓度已开始影响到我国的粮食产量。O3对植物的影响是由于其进入植物体内发生生化反应所引起的,所以需要建立一种考虑到植物生理生态状况的评估指标来评估O3对植物的影响。其中基于O3通量(特别是植物气孔吸收)的评价指标和方法,被认为比传统的基于O3浓度的评价指标和方法更符合O3对植物的影响机理。介绍了O3对生态系统影响评估方法和评价指标,重点评述了生态系统尺度O3通量观测和气孔吸收估算的主要方法以及在不同生态系统上的研究进展分析了我国关于O3对植物和生态系统影响的研究现状,并对未来的研究工作进行了展望。     

激光对珠子参愈伤组织诱导影响的研究

通过不同激光功率密度和处理时间处理珠子参植株,然后分别用珠子参的茎和叶做外殖体进行愈伤组织诱导。结果表明,不经激光处理,珠子参茎和叶的愈伤组织诱导率分别为45.3%和0.7%。经激光处理后,珠子参茎和叶愈伤组织诱导率分别最高达到了92.0%和6.7%。经t检验,激光处理后,外殖体的愈伤组织诱导率与对照相比达到了显著性差异,表明激光处理有助于珠子参愈伤组织的诱导。     

Effects of major ozonated autoheamotherapy on functional recovery,ischemic brain tissue apoptosis and oxygen free radical damage in the rat model of cerebral ischemia

Stroke is the second leading cause of death and disability in the world, with a heavy burden on patients, their families, and society. At present, a major focus of cerebrovascular disease research is to find a safe and effective new method to promote early functional recovery in the acute phase of cerebral infarction. Major ozonated autohemotherapy (MOAH) can maintain ATP and energy metabolism in cerebral ischemia and hypoxia, and reduce cell apoptosis. In the current study, the model of middle cerebral artery occlusion in the Sprague Dawley rat was established and evaluated by the clinical functional score, Hoechst staining, immunohistochemistry, Western blot analysis, and biochemical detection. Then, the effects of MOAH on neurological function, apoptosis, and oxygen free radical damage after acute ischemia in middle cerebral artery were evaluated. Moreover, the potential two mechanisms have been illustrated for MOAH effects. This study would lay a theoretical foundation for the application of MOAH and find an effective and early treatment method for the cerebral infarction.