大气颗粒物对植物影响研究进展

大气颗粒物是大气中固态或液态微粒物质的总称。大气颗粒物的增多会对气候、空气能见度、公共卫生等造成重大影响。种植合适的植物成为减轻大气颗粒损害的良好措施,但大气颗粒物覆盖在植物叶片表面及进入植物体内都会对植物造成不同程度的影响。本文围绕大气颗粒物的成因及组成,大气颗粒物对植物生长发育、生理生化、抗病虫性、植物生产力和产量的影响方式及机理与减轻途径等进行了系统综合与评述,并展望了未来的研究趋势。综合发现,大气颗粒物对植物的影响广泛且复杂多样,并受到环境条件、颗粒物浓度及组成、植物种类及研究尺度的影响。通过提前预知大气颗粒物浓度变化、提供充足的营养和水分、及时冲洗叶片、人工补光及合理选择并种植植物等方式可避免或者减轻大气颗粒物所带来的负面效应。未来可增加大气颗粒物影响下景观和造林植物的研究、大尺度植被生理生态、各种化合物和微生物颗粒物对植物影响的研究,研究内容可关注植物生理生态、植物叶片氮分配、叶肉细胞导度及植物遗传育种学等。     

大气颗粒物对健康的影响

<正>近年来研究发现,大气颗粒物严重影响人体健康,PM2.5每年造成80万人死亡,排在所有致死因素的第13位[1].大气颗粒物是悬浮于空气中颗粒的总称,按照其空气动力学粒径分为总悬浮颗粒物(TSP空气动力学直径小于100μm,下同)、可吸入颗粒物(PM10)、细颗粒物(PM2.5)和超细颗粒物(PM0.1)[2].不     

支气管扩张合并支气管哮喘患者支气管肺泡灌洗液病原菌培养及药敏状况研究

目的:对支气管扩张合并支气管哮喘患者支气管肺泡灌洗液病原菌培养及药敏状况展开分析,实现多药耐药医院感染的有效预防与控制。方法:随机选取2010年9月~2013年8月期间收治的50例支气管扩张症合并支气管哮喘患者,对50例患者支气管肺泡灌洗液标本进行病原学检测及药敏试验,并对临床感染资料及病原菌耐药性进行统计学分析。结果:50例支气管扩张症合并支气管哮喘患者支气管肺泡灌洗液培养阳性率为30例,60.0%,共分离出48株细菌。其中,革兰阳性球菌5株,占分离菌的10.4%;革兰阴性杆菌41株,占分离菌的85.4%;真菌2株,占分离菌的4.2%。41株革兰阴性杆菌对抗菌药物的耐药性分别为:复方新诺明73.1%,阿米卡星22.0%,环丙沙星14.6%,头孢曲松48.8%,头孢噻肟41.5%,头孢哌酮19.5%,头孢他啶20.7%,头孢他啶/舒巴坦12.1%,头孢吡肟22.0%,庆大霉素17.1%,阿莫西林/克拉维酸41.5%,哌拉西林/他唑巴坦19.5%。结论:铜绿假单胞菌是支气管扩张合并哮喘患者感染中的常见病原菌,医务人员要结合病原菌高耐药率、高分离阳性率的特征,合理运用抗菌药物控制传播。     

模拟大气细颗粒物中镉沉降对小白菜的毒性效应研究

为探究大气细颗粒物中镉(Cadmium,Cd)沉降对小白菜(Brassica rapa var.chinensis(L.)Kitamura)的毒性效应,本研究模拟不同浓度梯度大气细颗粒物中镉沉降(0、150、300和500μg/m3),分别代表对照、轻度、重度和严重污染,检测幼苗受胁迫后的生长状况、叶绿素相对含量(SP...     

城市园林树木叶面微结构特征对大气颗粒物滞留能力的影响

园林植物叶面微结构会影响其截留大气颗粒物的能力。选取乌鲁木齐市主干道10种常见落叶阔叶树种,采用水洗滤膜法测定不同树种单位叶面积对空气总悬浮颗粒物(TSP)、大颗粒物(PM_>10)、粗颗粒物(PM_3—10)和细颗粒物(PM_1—3)的滞纳量,探究不同粒级颗粒物含量及其占总颗粒物含量的百分比;用高倍电子显微镜观察叶表面微形态特征(绒毛长度、气孔半径、凹槽宽度等),分析叶表面在微观结构下各形态特征与其不同粒级颗粒物吸附能力间的相关性。结果表明：不同树种单位叶面积颗粒物滞纳量表现出较大差异,其中榆树总颗粒物滞纳量最高(53.38±0.71)μg,是红瑞木总颗粒物滞纳量(4.90±0.64)μg的10倍;PM_>10颗粒物平均含量占TSP约80%。榆树的PM_3—10、PM_1—3滞纳量最高,达(9.14±1.08)μg和(7.75±0.05)μg,是其他树种的3—5倍。气孔数量与TSP、PM_>10颗粒物含量呈显著正相关性,相关系数...     

大气细颗粒物影响小鼠上、下呼吸道菌群结构

探讨影响人类健康的大气细颗粒物干扰小鼠上呼吸道和下呼吸道菌群定植及可能机制。

建立大气细颗粒物暴露的小鼠模型。BALB/c小鼠随机分为PM2.5暴露组和对照组, 每组10只。收集上呼吸道和下呼吸道灌洗液进行菌群测序分析, 并进行肺组织HE染色, 观察肺组织形态改变情况。

大气细颗粒物暴露小鼠, 破坏肺组织气血屏障结构。16S rRNA测序证实了上、下呼吸道微生态的组成因大气细颗粒物暴露而发生改变。明确了与细颗粒物暴露组相比较, 对照组的噬几丁质菌定植的丰度较高。

大气细颗粒物影响小鼠上、下呼吸道的微生态结构。研究发现的差异菌群改变将会成为新的肺损伤治疗的潜在菌群。

     

森林植被与大气颗粒物的关系

近年来,大气颗粒物成为我国城市大气的主要污染物,其中细颗粒物（PM_2.5）粒径小、沉降困难,对环境的危害已成为亟待解决的问题。森林植被可显著消减空气颗粒物,有效改善空气环境质量。本文概述了植被对颗粒物的移除过程和方法,探讨了大气颗粒物与森林植被的相互关系。从单叶、单木及群落3个尺度,结合气象因素讨论了植被对移除大气颗粒物的影响,分析了颗粒物的后续再悬浮过程及对植被的危害。最后,从植被吸附颗粒物的能力测定和评价、本土高吸附PM_2.5能力植被的筛选及综合研究不同植被配置结构的吸附效应等方面提出了植被吸附颗粒污染物,尤其是细颗粒物的研究重点与趋势。     

北方城市绿地对大气颗粒物浓度的削减作用对比研究

尽管城市绿地能够改善空气质量,但由于实践中缺乏统一的绿地分类系统,很难从优化绿地植被结构的角度出发调节城市空气质量。因此,为了探究北方城市不同绿地削减大气颗粒物浓度效果的差异,构建了一套融入植被结构因子和物种组成的绿地分类系统,基于该分类系统,在北京、西安、宝鸡选取了5类共同常见的植被结构绿地类型,通过卫星图像判读与实地监测相结合的方式,探究了不同本底环境、植被结构、植物多样性、气象因子和时间因子对大气颗粒物浓度(PM_2.5与PM₁₀)的影响。结果表明：（1）城市绿地率对大气颗粒物浓度造成显著影响,绿地率越高的本底环境内颗粒物浓度越低,即多绿本底<灰绿参半本底<灰色本底;（2）植被结构和植物多样性水平显著影响绿地的滞尘能力,北方城市中半开敞绿地的滞尘能力最好,其次为半闭合绿地与闭合绿地,开敞绿地滞尘能力最弱,植物多样性的增加将导致绿地内颗粒物浓度增加;（3）不同植被结构绿地内的大气颗粒物浓度受气象因素的显著影响,随温度和风速的增大而减小,随湿度的增大而增大;（4）北方城市绿地大气颗粒物浓度存在明显的季节和日变化规律,一年内大气颗粒物浓度在夏季最低,冬季最高;一天之内颗粒物浓度在8:00—10:00最低。上述研究结果以期为今后不同本底环境下以削减大气颗粒物浓度为导向的北方城市绿地规划与设计提供理论依据和实践方法。     

支气管肺泡灌洗联合局部注药治疗支气管扩张合并感染的临床观察

目的:观察支气管肺泡灌洗联合局部注药治疗治疗支气管扩张合并感染的的临床效果。方法:将所选取的114名支气管扩张合并感染的患者随机分为对照组(使用常规方法进行治疗)和实验组(在常规治疗的基础上,给予支气管肺泡灌洗联合局部注药方法进行治疗)。比较两组患者治疗后症状改善情况、血气指标、治疗时间、半年内再次就诊次数。结果:与治疗前相比,两组患者治疗后血气指标均有明显改善,差异均有统计学意义(P0.05);治疗后实验组血气指标相比对照组改善更明显,差异具有统计学意义(P0.05);实验组患者退热时间、咳嗽咳痰消失时间、湿罗音消失时间、平均住院时间、半年内再次就诊次数均短于对照组,差异均有统计学意义(P0.05);观察组患者总有效率为100%,高于对比组的89.5%,差异有统计学意义(P0.05)。结论:支气管肺泡灌洗联合局部注药治疗治疗支气管扩张合并感染能有效改善患者症状,显著提高治疗效果,降低疾病的复发率,值得临床推广。     

大气颗粒物对儿童健康的影响及其机制

本文综述大气颗粒物对儿童肺功能、免疫功能、生长发育、肿瘤生成等的影响及其机制,探讨大气颗粒物对儿童健康的影响.     

In vitro effect of air pollutants on human bronchi

A useful approach for constructing dose–response relationships and for studying the underlying mechanisms by which a xenobiotic agent enhances airway reactivity is to measure the response of an isolated airway following ex vivo exposure to a pollutant. We have in this way determined the dose–response relationship between ex vivo exposure to pollutants such as nitrogen dioxide (NO₂), the aldehyde acrolein, and ozone (O₃) and the reactivity to agonists in human isolated bronchial smooth muscle. We have also investigated the underlying alteration in the cellular mechanisms of airway smooth-muscle contraction induced by such exposure and found that it is related to alteration in calcium signaling at the site of the airway smooth-muscle cell. Finally, although there is epidemiological evidence that an increase in allergic diseases such as asthma may be linked to air pollution, there are few experimental data to address this issue. The final aim of this study was therefore to investigate the interaction between passive sensitization and exposure to pollutants in human isolated airways. We have examined (i) the effect of a pre-exposure to pollutants on the contraction of sensitized bronchi in response to a specific antigen and (ii) the effect of passive sensitization on the contraction in response to nonspecific agonists in bronchi pre-exposed to pollutants. The results indicate a combined effect of immunological sensitization and exposure to pollutants; that is, passive sensitization and exposure to pollutants act in a synergistic manner on human bronchial smooth-muscle reactivity in response to both specific antigens and nonspecific agonists. This revised version was published online in August 2006 with corrections to the Cover Date.     

The relationship between Japanese cedar pollinosis and air pollutants deposited on the pollen

In this study, air pollutants such as NO ₃ ^– and SO ₄ ^–2 which were found deposited on Japanese cedar pollen in a mountainous area (Tsukechi-cho), and in an urban area (Mizuho Ward, Nagoya City) were measured by ion-chromatography in March 1987 and again in March 1991. An investigation of the pollinosis rate in about 400 Junior High School students in both areas was undertaken during the same periods through both a questionnaire study, and a physical examination. Information was also gathered on the number of vehicles passing through the corresponding areas. The results of this research are as follows: (1) The quantity of NO ₃ ^– deposited on the pollen of Japanese cedar was about 2.3 and 2.0 times greater in the urban area than in the mountainous area (1987 and 1991, respectively). The concentration of SO ₄ ^–2 was about 7.8 and 3.6 times higher in the urban area than in the mountainous area (1987 and 1991, respectively). (2) The results of a questionnaire study taken at the two Junior High Schools from the different districts showed a lower incidence of nasal symptoms in the mountainous area than in the urban area for 1987. The percentage of pollinosis shown by physical examination in the mountainous area rose from 20.1% in 1987 to 30.0% in 1991, and this corresponds to a rise in the number of motor vehicles in the area. Comparatively, in the urban area, the questionnaire results and physical examinations revealed no changes from 1987 to 1991.     

Comparison of two numerical models on photosynthetic response ofQuercus mongolica leaves to air pollutants

A multiple-regression model is presented for estimating the effect of major air pollutants on net photosynthetic rate (Pn) ofQuercus mongolica leaves, of which visible injury is not shown. Photosynthetic capacity was found to be primarily a function of PPFD, air temperature (T) and ambient ozone (O₃) concentration. The negative direction of photosynthetic capacity response to O₃ concentration indicates a potential growth reduction ofQ. mongolica due to ambient O₃ concentration in the urban areas of Korea. The model was compared with a non-linear regression model including the same variables. We assessed the contribution of variables to two two models of ambient O₃ affecting Pn ofQ. mongolica leaves. The mean Pn difference between the models with and without ambient O₃ in the multiple-regression was smaller than that in the non-linear regression. The relative contributions of ambient O₃ to multiple-regression and non-linear regression were 12.6% and 5.6%, respectively. The results indicate that multiple-regression models can be applicable for qualitative or quantitative assessment of the effect of air pollutants on Pn response of plant leaves, of which visible injury may not be shown in situ. Also, the assessment of ecophysiological effects using numerical models will have a degree of uncertainty associated with the measuring time/period of the field data used in the modelling, as well as the numerical structure of the models.     

The effect of air pollutants on physiological processes in plants

Abstract. Important physiological processes, photosynthesis, respiration, carbon allocation and stomatal function are known to be affected by air pollutants. A wide range in sensitivity of photosynthesis both within and between species is evident from the literature for the pollutants sulphur dioxide, ozone, nitrogen oxide and hydrogen fluoride. Some of this variation is clearly due to genetic factors, but much is in response to differences in environmental conditions both prior to and during fumigation. Exposure of plants to mixtures of pollutants generally reduced the threshold at which effects were first detected and increased the level of inhibitory responses. In the majority of studies on stomatal responses to air pollutants, opening occurs at low concentrations, below the threshold for effects on photosynthesis, and closure occurs at injurious concentrations; this latter response often following the inhibition of photosynthesis. Effects on carbon allocation have been reported in response to air pollutants. Changes usually favour leaf development over root growth, which can compensate for a decline in net assimilation rate up to a certain point but may limit water uptake from soils with low moisture content. Future research into physiological effects of air pollutants should incorporate an integrated approach in which both key physiological parameters and growth parameters are measured together with estimates of the effective dose of pollutant. In this way, the underlying mechanisms to changes in growth and development will be more fully understood.     

Spectrophotometric analysis as a complementary technique to aerobiology in the study of solid particles in the air

Hitherto, aerobiology has mainly focused on studying and analysing the biologic material found in the atmosphere (pollen grains and fungal spores), due to its allergologic and agricultural interest. However, the increase in respiratory tract problems caused by other solid particles suspended in the air has made studies including biologic and non-biologic material more frequent. This paper describes a simple technique based on spectrophotometric analysis. The results thus obtained can complement the outcome obtained by traditional aerobiologic techniques if the method is used properly and the equipment properly calibrated and an idea of the solid particles in the air can be obtained. The combination of both aerobiological and spectrophotometric analysis makes it possible to estimate the concentration of solid-particle material in the air, and we can also estimate the percentage of pollen grains and fungal spores among the general spectrum of particles. The results also show that a great part of the solid particulates originate from human activities. However, it was also observed that they emerge from natural sources as such as fungi and higher plants.     

Orthogonal arrays of particles in the gill epithelium of the Atlantic hagfish,Myxine glutinosa

Summary Freeze-fracture replicas of hagfish gill epithelium revealed orthogonal arrays of 6-nm particles in the basolateral plasma membrane of pavement cells. The arrays consisted of 4–16 particles and occupied an area of 340±170 nm². These particle arrays, which are considered to be sites of ionic leakage, possibly contribute to the regulation of the pericellular micromilieu of adjacent mitochondria-rich cells.     

心房颤动模型中实验动物优化的研究进展

房颤动物模型的建立对于研究房颤的机制以及治疗方法有着极其重要的作用。而房颤医学模型需要较长时间才能获得,对实验动物有一定的特殊要求,并且影响较大。这样,实验动物优化,即实验动物福利的改良与发展就显得重要,是促进建模成功的重要保障。我们从伦理与法规支持,饲养管理,替代方法和福利技术四个方面综述心房颤动医学模型中实验动物福利的改良与发展。     

Influence of air pollutants and nutrient deficiency on D-1 protein content and photosynthesis in young spruce trees

Long-term fumigation with different mixtures of air pollutants, such as O₃, NO₂ and SO₂, in combination with potassium deficiency in 4-year-old spruce trees shows clearly that the photosynthetic apparatus reacts very sensitively to environmental stress. Even when no change in photosynthetic oxygen evolution of the leaves was measurable, the content of D-1 protein in the reaction center of photosystem II already increased significantly at low stress conditions. With increasing concentrations of pollutants, the content of D-1 protein decreased considerably. This pattern was observed with all combinations of gases, although they differed in effectiveness. The most potent effect on the content of D-1 protein was found with a combined fumigation of SO₂ plus NO₂. Obviously, the ratio between synthesis and degradation of the D-1 protein is influenced by stress factors. However, the content of D-1 protein was not strongly correlated with photosynthetic oxygen evolution in whole needles nor with electron transport rate in isolated thylakoids. Under controlled potassium deficiency, effects similar to those observed upon ozone fumigation developed. The results suggest unspecific stress answers for the D-1 content and the photosynthetic reactions rather than specific responses.     

The pollutants in rime and fog water and in air at Milesovka Observatory (Czech Republic)

Samples of rime/fog water and dust in the air were collected in order to compare concentrations of pollutants. Particular attention was paid to particles of heavy metals (Al, As, Cu, Fe, Pb, Ti and Zn). The concentrations of pollutants from the air are different in rime water and fog water. Both (fog) water and ice crystals fixed Ti, Cu, As and Pb ions minimally (less than 1%). Rime captured 11.6% Al, 9.3% Zn, 4.4% Fe and 91.2% Mn from the air. Fog water absorbed 9.8% Al, 9.0% Fe, 55.6% Mn, and 48.7% Zn from the air. Fog water absorbed Zn much better (48.7%) than rime (9.3%). Rime absorbed Mn better (91.2%) than fog water (55.6%).     

Meteorological phenomena affecting the presence of solid particles suspended in the air during winter

Winter is not traditionally considered to be a risky season for people who suffer from pollen allergies. However, increasing numbers of people are showing symptoms in winter. This prompted our investigation into the levels of solid material in the air, and some of the meteorological phenomena that allow their accumulation. This study showed a possible relationship between the phenomenon of thermal inversion, which occurs when very low temperatures, cloudless skies and atmospheric calms coincide, and an increase in the concentration of solid material in the atmosphere. Frequently, this situation is associated with other predictable phenomena such as fog, dew and frost. This may allow a warning system to be derived for urban pollution episodes. The effect caused by parameters such as wind and rainfall was also analysed. Solid material was differentiated into non-biological material from natural and non-natural sources (e.g. soot, dust, sand, diesel exhaust particles, partially burnt residues) and biological material. The latter mainly comprises pollen grains and fungal spores. Owing to its abundance and importance as a causal agent of winter allergies, Cupressaceae pollen was considered separately. Received: 28 April 1999 / Revised: 16 November 1999 / Accepted: 17 November 1999