Absorption of air pollution by plants, and consequences for growth

There is now great concern that air pollutants (especially sulfur dioxide, ozone, and oxides of nitrogen) can alter the physiological processes of plants, thereby affecting patterns of growth. Air pollutants cause damage to leaf cuticles and affect stomatal conductance. They can also have direct effects on photosynthetic systems, leaf longevity, and patterns of carbon allocation within plants. Pollutants interact with other environmental factors, and may alter plant-environment relationships on a regional scale. In this article, Winner and Atkinson summarize current knowledge of the effects of air pollutants on plant growth and physiology, and indicate the new directions of research now under way in North America and Europe.     

Dynamics of plant responses to combinations of air pollutants

The focus of this review is on how plants respond to combinations of multiple air pollutants. Global pollution trends, plant physiological responses and ecological perspectives in natural and agricultural systems are all discussed. In particular, we highlight the importance of studying sequential or simultaneous exposure of plants to pollutants, rather than exposure to individual pollutants in isolation, and explore how these responses may interfere with the way plants interact with their biotic community. Air pollutants can alter the normal physiology and metabolic functioning of plants. Here we describe how the phenotypic and molecular changes in response to multiple pollutants can differ compared to those elicited by single pollutants, and how different responses have been observed between plants in the field and in controlled laboratory conditions and between trees and crop plants. From an ecological perspective, we discuss how air pollution can result in greater susceptibility to biotic stressors and in direct or indirect effects on interactions with organisms that occupy higher trophic levels. Finally, we provide an overview of the potential uses of plants to mitigate air pollution, exploring the feasibility for pollution removal via the processes of bio‐accumulation and phytoremediation. We conclude by proposing some new directions for future research in the field.     

Effects of air pollution on biogenic volatiles and ecological interactions

Chemical signals play important roles in ecological interactions but are vulnerable to perturbation by air pollution. In polluted air masses, signals may travel shorter distances before being destroyed by chemical reactions with pollutants, thus losing their specificity. To determine which scent-mediated interactions are likely to be affected, we review existing literature to build a picture of what chemicals are commonly found in such interactions and the spatial scales at which interactions occur. We find that pollination, attraction of natural enemies of plant pests, aggregation pheromones, and mate attraction are likely to be affected. We review the scant literature on this topic and extend the hypothesis to include heretofore unexplored interactions. New research should investigate whether air pollution deleteriously affects populations of organisms that rely on scent plumes. Additionally, we need to investigate whether or not breakdown products created by the reaction of signaling chemicals with pollutants can provide usable signals, and whether or not there has been adaptation on the part of scent emitters or receivers to use either breakdown products or more robust chemical signals. The proposed research will necessarily draw on tools from atmospheric science, evolutionary biology, and ecology in furthering our understanding of the ecological implications of how air pollution modifies the scentscape.     

Recent Findings on the Phytoremediation of Soils Contaminated with Environmentally Toxic Heavy Metals and Metalloids Such as Zinc,Cadmium, Lead,and Arsenic

Due to their immutable nature, metals are a group of pollutants of much concern. As a result of human activities such as mining and smelting of metalliferous ores, electroplating, gas exhaust, energy and fuel production, fertilizer and pesticide application, etc., metal pollution has become one of the most serious environmental problems today. Phytoremediation, an emerging cost-effective, non-intrusive, and aesthetically pleasing technology, that uses the remarkable ability of plants to concentrate elements and compounds from the environment and to metabolize various molecules in their tissues, appears very promising for the removal of pollutants from the environment. Within this field of phytoremediation, the utilization of plants to transport and concentrate metals from the soil into the harvestable parts of roots and above-ground shoots, i.e., phytoextraction, may be, at present, approaching commercialization. Improvement of the capacity of plants to tolerate and accumulate metals by genetic engineering should open up new possibilities for phytoremediation. The lack of understanding pertaining to metal uptake and translocation mechanisms, enhancement amendments, and external effects of phytoremediation is hindering its full scale application. Due to its great potential as a viable alternative to traditional contaminated land remediation methods, phytoremediation is currently an exciting area of active research.     

Monitoring the environment by remote sensing

Structural features of ecosystems, such as leaf area index, phytomass and canopy chemical contents, are beginning to be estimated from remotely sensed data. This development, in combination with ecological modeling, is permitting the estimation of functional features of ecosystems including primary productivity and nutrient cycling. Such techniques are also being applied to the problem of monitoring the effects of air or water pollutants on biota. Sensors that obtain data at a coarse spatial scale (1 km(2) or more) are also permitting the observation of biospheric patterns at a large regional or global scale for the first time. When coupled with atmospheric measurements, field data and simulation models, such data may serve to address ecological processes, including pollution effects, at large regional or global scales.     

Air pollution and the lung: epidemiological approach

Epidemiological evidence has concurred with clinical and experimental evidence to correlate current levels of ambient air pollution, both indoors and outdoors, with respiratory effects. In this respect, the use of specific epidemiological methods has been crucial. Common outdoor pollutants are particulate matter, nitrogen dioxide, carbon monoxide, volatile organic compounds and ozone. Short-term effects of outdoor air pollution include changes in lung function, respiratory symptoms and mortality due to respiratory causes. Increase in the use of health care resources has also been associated with short-term effects of air pollution. Long-term effects of cumulated exposure to urban air pollution include lung growth impairment, chronic obstructive pulmonary disease (COPD), lung cancer, and probably the development of asthma and allergies. Lung cancer and COPD have been related to a shorter life expectancy. Common indoor pollutants are environmental tobacco smoke, particulate matter, nitrogen dioxide, carbon monoxide, volatile organic compounds and biological allergens. Concentrations of these pollutants can be many times higher indoors than outdoors. Indoor air pollution may increase the risk of irritation phenomena, allergic sensitisation, acute and chronic respiratory disorders and lung function impairment. Recent conservative estimates have shown that 1.5-2 million deaths per year worldwide could be attributed to indoor air pollution. Further epidemiological research is necessary to better evaluate the respiratory health effects of air pollution and to implement protective programmes for public health.     

景观生态学在大气污染研究中的应用

快速城市化和工业化进程造成了一系列大气污染问题,亟需在宏观尺度上解析大气污染时空分布规律。景观生态学关注格局与过程耦合,景观"源汇"理论可对应解析大气污染物的源与汇效应,将景观生态学的理论与方法引入大气污染研究中已成为解决当前区域发展与大气污染权衡的有效途径。从景观生态学视角辨识了景观与大气污染物的源汇关系,系统梳理了景观格局与大气污染的定量关系,指出当前景观格局指标仍需进一步完善以表征大气污染时空分布特征,而高质量大气污染物时空数据的缺乏是限制景观格局与大气污染过程耦合分析的重要因素,拓展应用景观"源汇"理论,定量解析景观格局对大气污染的源汇效应,同时进一步研发遥感反演技术,实现大气污染物分布格局的精细刻画,将为区域景观规划提供重要支撑。强化大气污染研究中的景观生态学分析途径,将有助于深化景观生态学格局与过程耦合研究体系,也将为景观可持续管理提供有力的科学支撑。     

森林火灾污染物质释放及其影响研究进展

森林火灾是大气中气体污染物和颗粒物的重要来源,可对全球气候系统、大气环境以及生态系统产生重要影响,对全球温室气体和含碳颗粒物释放具有重要的贡献,是推动全球气候变化的重要因素。森林火灾释放污染物已成为区域乃至全球范围内重要污染源之一,这些污染物质与辐射、能见度以及温室效应等问题直接相关。准确地描述森林火灾释放的气体和颗粒污染物释放机理、释放总量、时空分布特征、不同尺度的扩散过程模拟,以及对区域大气环境的影响,对于量化森林火灾释放污染物总量及区域影响具有重要意义。基于森林火灾污染物质释放方面的国内外文献,从火灾释放的污染物质对环境的影响、森林火灾释放污染物定量化和传输路径监测的研究方法、污染物质的扩散和运输模型以及跨区域影响等几个方面进行了综述。森林火灾释放的CO、PM₁₀和PM_2.5对环境和人的生命安全造成巨大威胁,而且森林火灾释放的污染物质能够随气流长距离传输,不仅对当地的空气造成污染,污染物也能够随着气团进行长距离传输,并在传输过程与当地气溶胶混合,形成跨区域污染。森林火灾释放污染物扩散、传输模拟通过不同模型相互耦合完成,包括可燃物载量估算模型、可燃物消耗和释放模型、污染物扩散传输模型,以及污染物预测和可视化模型等。总结了国内外森林火灾释放污染物质主要研究方法,并展望了今后研究重点:目前我国关于森林火灾释放物质相关的研究尚不足以支撑我国森林火灾温室气体释放、污染物释放等方面的研究,并且我国目前还没有发展出适合于我国的森林火灾污染物释放模型,以及污染物扩散、传输系统。森林火灾排放因子库大多数引用国外研究结果,在一定程度上增加不确定性,缺乏森林火灾对区域大气环境影响的定量化研究。因此,今后我国应加强对森林火灾污染物质释放与影响的研究,尤其是污染物质扩散和传输模型的预测和可视化研究以及排放因子的测量。     

Insights into fluoride-induced oxidative stress and antioxidant defences in plants

Fluoride is a common pollutant which occurs in various environmental matrices considered as one of the most phytotoxic pollutants. It is essential to the living organisms in trace quantities but at its higher concentration it becomes poisonous. Excess amount of fluoride in environment not only exerts its toxic effects on human beings and animals but also on plants. Toxicological impacts of fluoride on plants have been largely debated due to reduction of growth parameters, inhibition of metabolic activities and decreased photosynthetic activity. The signs of fluoride impacts on plants may be severe, acute or chronic and toxicity of fluoride depends on dose, frequency of exposure, duration and genotype of plant. This article overviews understanding of transport, uptake and fluoride accumulation in plants and provide insights into the fluoride-induced oxidative stress and regulatory mechanisms to cope up with it. The main objective of this article is to prospect new research avenues to unravel the mechanisms explaining fluoride toxicity in various plant species.     

中国东北地区非点源污染研究进展

为掌握东北地区非点源污染研究动态和明确研究中存在的问题和不足,对近20年（1991-2008年）东北地区有关非点源污染研究成果进行检索、分类和统计分析,以便更好地进行区域水环境治理和污染防治.东北地区非点源污染研究总体呈增加趋势;研究内容包括水环境污染源调查分析与评价、污染负荷量化、机理探索、模型模拟和污染防治5类;研究对象包括氮、磷、泥沙、农药和重金属;经验方法估算污染负荷较多,机理模型应用成功实例较少;研究性论文中以农业非点源污染较多,城市非点源污染较少;治理措施停留在水土保持措施层面上,缺乏对水土保持措施的优选评价和对最佳管理措施的评价研究.目前,东北地区非点源污染研究处在理论探索阶段,非点源污染是否是主要污染源还存在争议.今后应着力于措施应用、评价和基础数据收集及区域非点源污染物的确定和污染负荷的量化研究;尝试新技术和多领域交叉合作,为区域水环境治理提供科学依据.     

尘污染对植物的生理和生态特性影响

综述了尘污染对植物和植物群落的生理和生态作用和影响,并初步探讨了其原因和机制。尘污染能影响植物的光合作用、呼吸作用和蒸腾作用,并携带有毒性污染物穿透进入植物组织。尘污染会导致植物发生可见的伤害症状,引起生产力的下降。大部分的植物群落也会受到尘的影响而改变群落结构。今后要加强对自然条件下尘对植物影响的深入研究和植物不同种类间对尘敏感性的差异的研究。     

内生菌协同宿主植物修复土壤复合污染的研究进展

土壤复合污染日益严重,危及植物生长及人类发展,寻找修复土壤复合污染的有效方法已经成为环境领域的优先事项。复合污染指同一环境中存在两种或两种以上的污染物,分为复合重金属污染、复合有机污染物污染及重金属-有机污染物复合污染。近些年发现内生菌能定殖在植物中,并且被感染的植物不会引起任何外在病症,其主要通过促进宿主植物生长,改变植物摄取污染物能力和酶促降解污染物等方法增强植物修复能力。本文综述了具有复合重金属和复合有机污染抗性的内生菌种类及其作用机制,并展望了内生菌协同宿主植物修复环境中复合污染物的研究方向。     

红树林重金属污染生态学研究进展

红树林湿地,由于其固有的一些特性,能够大量接受来自潮汐、河水、地表径流所携带的重金属污染物.近30a来,红树林湿地重金属污染问题已引起了国内外学者们的极大关注,并对此进行了大量的研究.分别对重金属在红树林湿地中的分布与迁移、红树植物对重金属的生长响应及耐性机理等方面的研究进展和存在的问题进行了综述;此外,还对红树林湿地重金属净化效应的相关研究进行简要的概述.最后,对今后的研究趋势提出了一些看法.     

根系分泌物及其在植物修复中的作用

 近年来环境污染日益严重,污染物在土壤植物中的行为引起了人们的高度关注。利用植物去除土壤水体等介质中污染物的植物修复是近10年来兴起的一项安全、廉价的技术,已成为污染生态学和环境生态学的研究热点,它通过植物吸收、根滤、稳定、挥发等方式清除环境中的重金属和有机污染物。国内外有关植物修复的研究报道和概述很多, 但对植物根系分泌物在植物修复中所起的作用及其机理少有述评。 本文从根系分泌物对土壤重金属和土壤有机污染物的去除作用出发,对根系分泌物的种类、数量及其在去除环境污染物中的作用机理和功能地位进行了总结,并借助研究事例对影响植物根系分泌的内外因子,如植物种类、营养胁迫、重金属胁迫、根际环境的理化性质、土壤微生物及其它环境因子进行了讨论。概言之,根系分泌物在修复污染土壤中的重金属途径是多种多样的,主要是通过调节根际pH值、与重金属形成螯合物、络合反应、沉淀、提高土壤微生物数量和活性来改变重金属在根际中的存在形态以及提高重金属的生物有效性,从而减轻它对环境的危害。在清除有机污染物时,根系分泌物中的酶可以对有机污染物进行直接降解,根系分泌物影响下的微生物也可以对有机污染物进行间接降解,且被认为是主要的降解途径。根系分泌物在植物修复过程中确实起着某些重要作用,今后应将这方面的研究重点放在某些特异性根系分泌物植物,尤其是某些重金属超富集植物资源的寻找、筛选上,通过室内实验和野外研究确定其根系分泌物对清除重金属和有机污染物的效率,证实超富集植物根系分泌物的特异性与污染物超富集的内在联系,找到污染土壤生态恢复和治理的有效方法并加以推广应用,如针对性地在被污染地大面积种植此类具特异性根分泌物植物,并辅以营林措施如修剪等,加快生物修复进程,提高修复效率。植物根系分泌物在植物修复过程中所具有的重要生态意义和可能应用前景,为污染生态学和化学生态学之间的联合研究开拓了全新的领域,今后将取得新的突破和重要进展。     

Anthropogenic pollutants: a threat to ecosystem sustainability?

Pollutants, including synthetic organic materials and heavy metals, are known to adversely affect physiological systems in all animal species studied to date. While many individual chemicals can perturb normal functions, the combined actions of multiple pollutants are of particular concern because they can exert effects even when each individual chemical is present at concentrations too low to be individually effective. The biological effects of pollutants differ greatly between species reflecting differences in the pattern of exposure, routes of uptake, metabolism following uptake, rates of accumulation and sensitivity of the target organs. Thus, understanding of the effects of pollutants on wildlife and ecosystems will require detailed study of many different species, representing a wide range of taxa. However, such studies can be informed by knowledge obtained in more controlled conditions which may indicate likely mechanisms of action and suitable endpoint measurements. Responses may be exacerbated by interactions between the effects of pollutants and environmental stressors, such as under-nutrition or osmotic stresses and so changes in such variables associated with climatic changes may exacerbate physiological responses to pollutant burdens.     

滩涂底栖动物有机污染生态学研究进展

底栖动物由于对有机污染物具有较强的吸收能力,再加上其移动能力较差、生活方式比较固定,而被广泛运用于滩涂有机污染的研究.目前这些研究主要集中在如下几个方面：（1）有机污染物在底栖动物体内的分布特征及在底栖食物链中的动力学研究;（2）底栖动物对有机污染物的生理响应研究;（3）污染物对底栖动物群落组成和结构影响研究;（4）底栖动物在滩涂有机污染检测中的应用研究.研究结果表明：滩涂底栖动物对有机污染物的累积具有选择性和季节波动性;有机污染物可以在底栖食物链中传递;底栖动物体内的有机污染物成分和含量可以有效地指示其生存环境的有机污染状况;底栖动物的混合功能氧化酶和抗氧化酶系统对体内有机污染物的累积产生积极的响应;有机污染物对底栖动物的免疫系统造成不利影响,并对遗传物质造成破坏;有机污染对底栖动物的群落组成和结构具有显著的影响.     

How parasitism and pollution affect the physiological homeostasis of aquatic hosts

Parasitism poses a serious threat to hosts under certain circumstances, while the well-being of organisms is also negatively affected by environmental pollution. Little information is available on the simultaneous effects of parasites and pollutants on the physiological homeostasis of organisms. The present paper demonstrates that parasites: (i) may influence the metabolism of pollutants in infected hosts, (ii) interact with pollution in synergistic or antagonistic ways, and (iii) may induce physiological reactions in hosts which were thought to be pollutant-induced. Experimental studies on the uptake and accumulation of metals by fish reveal that fish infected with acanthocephalans have lower metal levels than uninfected hosts; e.g. Pomphorhynchus laevis reduces lead levels in fish bile, thereby diminishing or impeding the hepatic intestinal cycling of lead, which may reduce the quantity of metals available for fish. Alterations in pollutant uptake and accumulation in different intermediate and final hosts due to parasites are thus very important in the field of ecotoxicology. In addition to such alterations, there is a close interaction between the effects of pollutants and parasites which seems to be mediated at least partly by the endocrine system, which itself is closely related to the immune system in fish. Laboratory studies on eels experimentally infected with the swimbladder nematode Anguillicola crassus reveal that toxic chemicals such as polychlorinated biphenyls produce immunosuppressive effects which facilitate parasite infection. Similarly, an increase in serum cortisol concentration in eels due to chemical exposure and infection is correlated with decreasing levels of anti-A. crassus antibodies. Furthermore, parasites are able to elicit physiological changes which are attributed to chemicals with endocrine disrupting activity, e.g. the cestode Ligula intestinalis is known to suppress gonad development in roach. The most thoroughly documented examples of endocrine disruption in wild fish are in roach, and it is conceivable that this disruption is not only due to chemical activity but also to parasites such as L. intestinalis or species of the phylum Microspora.     

土壤生物与土壤污染研究前沿与展望

随着社会经济发展,人类生产活动对自然环境产生越来越广泛深刻的影响,土壤污染已成为危及生态系统稳定、农产品质量安全和人体健康的突出环境问题之一。重金属、有机污染化合物、病原菌及抗性基因等各类污染物大量进入土壤后,对土壤生物系统造成毒害作用,影响到土壤生态功能;另一方面,土壤生物如细菌、真菌、土壤动物等在一定程度上能够适应土壤污染,深刻影响着污染物在土壤中的迁移转化过程,在土壤污染修复中具有潜在重要作用。从土壤污染的生态毒理效应、土壤生物对土壤污染的响应与适应机制、污染土壤修复原理与技术等三方面综述了土壤生物与土壤污染相关研究前沿,展望了重点研究方向。