农药污染土壤的植物修复研究进展

植物修复是土壤农药污染修复的有效途径之一。植物主要通过直接吸收和代谢、根际土壤植物酶促降解和根际微生物对污染物的降解等三种机制去除土壤中残留的农药。本文简述了植物修复的含义和优点,系统地综述了植物修复农药污染土壤的机理,阐述了利用植物对农药污染土壤进行修复的研究成果和应用,并展望了今后需要进一步研究的领域。     

表面活性剂对植物修复有机污染土壤的增效作用及原理

Phytoremediation is becoming a cost-effective technology for the in-situ clean up of sites polluted with hydrophobic organic contaminants （HOCs）. The major factors limiting phytoremediation are the mass transfer, rate of plant uptake, and microbial biodegradation of HOCs. This article discusses the potential of surfactants to enhance desorption, plant uptake, and biodegradation of HOCs in the contaminated sites. Positive effects of surfactants on phytoremediation have been recently observed in greenhouse studies. The presence of some nonionic surfactants including polyoxyethylene sorbltan monooleate （Tween 80） and polyoxyethylene（23）dodecanol （Brij35） at relatively low concentrations resulted in significant positive effects on phytoremediation for pyrene-contaminated soil. However, the anionic surfactant （sodium dodecyl sulfate, SDS） and the cationic surfactant （cetyltrimethylammonium bromide, CTMAB） were not useful because of their phytotoxicity or low efficiency for surfactant-enhanced phytoremediation （SEPR）. The mechanisms of SEPR for HOC-contaminated sites were evaluated by considering experimental observations. In view of concerns about the cost effectiveness and toxicity of surfactants to plants, more research is needed to enhance the use of SEPR technology.     

Heritability of Phytoremediation Potential for the Alfalfa CultivarRiley in Petroleum Contaminated Soil

Petroleum contamination poses a significant threat to environmental ecosystems world-wide. Phytoremediation can be used to enhance degradation of petroleum contaminants in soil. However, selection of plants for phytoremediation has proven to be complicated. This research examines the heritability of the alfalfa cultivar Riley for phytoremediation based on parental total petroleum hydrocarbon (TPH) degradation after twelve months of growth. Traits other than degradation potential, such as root and shoot yield, height, and maturity, were examined for use as selection traits. Riley showed moderate to low heritability that suggests the possibility of breeding for phytoremediation efficiency. In addition, root and shoot yield were found to correlate to TPH degradation. Crosses in which the female parent was typically associated with low TPH dissipation yielded progeny that were high efficiency TPH degraders.     

Phytoremediation Technology: Hyper-accumulation Metals in Plants

This paper reviews key aspects of phytoremediation technology and the biological mechanisms underlying phytoremediation. Current knowledge regarding the application of phytoremediation in alleviating heavy metal toxicity is summarized highlighting the relative merits of different options. The results reveal a cutting edge application of emerging strategies and technologies to problems of heavy metals in soil. Progress in phytoremediation is hindered by a lack of understanding of complex interactions in the rhizosphere and plant based interactions which allow metal translocation and accumulation in plants. The evolution of physiological and molecular mechanisms of phytoremediation, together with recently-developed biological and engineering strategies, has helped to improve the performance of both heavy metal phytoextraction and phytostabilization. The results reveal that phytoremediation includes a variety of remediation techniques which include many treatment strategies leading to contaminant degradation, removal (through accumulation or dissipation), or immobilization. For each of these processes, we review what is known for metal pollutants, gaps in knowledge, and the practical implications for phytoremediation strategies.     

Uptake and phytotransformation of organophosphorus pesticides by axenically cultivated aquatic plants

The uptake and phytotransformation of organophosphorus (OP) pesticides (malathion, demeton-S-methyl, and crufomate) was investigated in vitro using the axenically aquatic cultivated plants parrot feather (Myriophyllum aquaticum), duckweed (Spirodela oligorrhiza L.), and elodea (Elodea canadensis). The decay profile of these OP pesticides from the aqueous medium adhered to first-order kinetics. However, extent of decay and rate constants depended on both the physicochemical properties of the OP compounds and the nature of the plant species. Malathion and demeton-S-methyl exhibited similar transformation patterns in all three plants: 29-48 and 83-95% phytotransformation, respectively, when calculated by mass recovery balance during an 8-day incubation. No significant disappearance and phytotransformation of crufomate occurred in elodea over 14 days, whereas 17-24% degraded in the other plants over the same incubation period. Using enzyme extracts derived from duckweed, 15-25% of the three pesticides were transformed within 24 h of incubation, which provided evidence for the degradation of the OP compounds by an organophosphorus hydrolase (EC 3.1.8.1) or multiple enzyme systems. The results of this study showed that selected aquatic plants have the potential to accumulate and to metabolize OP compounds; it also provided knowledge for potential use in phytoremediation processes.     

Pesticides‐non target plants interactions: An overview

Pesticides are widely used for crop protection in agriculture, plantation and forestry. Pesticides, when sprayed or dusted in the fields, only a small amount fall directly on the target organisms due to the small size and mobility of the pests. Most of them come to the soil or to the plants by direct precipitation or spray drift. Plants growing in the contaminated soil take up these chemicals along with water and mineral nutrients and translocate them to the aerial parts. Pesticides fallen on the leaf surface may find their way inside through leaf cuticle, stomata, hydrathodes, lenticels or tissues in the bark. Several factors influence pesticide uptake by plants. Pesticides are highly toxic chemicals and may not be absolutely specific in their actions. Impact of pesticide on plant depends upon its absorption, translocation and metabolism within the plant. Pesticides are usually detoxified in plants through series of degradation reactions and conjugation processes forming bound or insoluble residues. Failing to do so, plants show phytotoxic effects. Pesticides may affect different physiological processes in plants vital to their normal growth. They may also alter genetic materials in plants inducing gene mutation, chromosomal aberrations and chromosome break influencing their physiology and growth. Interaction of pesticides and their degradation products with non‐target plants is discussed here on different areas of research that are of particular interest in the context of this discussion.     

天然有机添加物提高植物修复污染土壤效率：研究进展综述.

Environmental pollution caused by metals, radionuclides and organic pollutants affects quality of the biosphere: soil, water and air.Currently, great efforts have been made to reduce, remove or stabilize contaminants in polluted sites. There has been increasing interest in phytoremediation—the use of plants to reduce concentration of pollutants or to render them harmless. This paper provides a brief review of recent progress in the research and practical application of phytoremediation techniques. Improvements in phytoremediation due to utilization of organic amendments, namely, agro- and industrial wastes(such as sugar beet residue, composted sewage sludge or molasses), biochar, humic substances, plant extracts and exudates are discussed, as well as their influences on soil structure and characteristics, plants growth and bioavailability of pollutants. Both plant-assisted phytoremediation and the use of natural materials in the absence of remediating plant are believed to be cost-effective and environmentally friendly approaches for soil cleanup. However,the characterization and quantification of a range of natural materials used in phytoremediation are essential in order to implement these approaches to practice.     

治理环境污染的绿色植物修复技术

环境污染是全人类面临的重大挑战。植物修复技术的出现及逐步完善,为人类治理环境污染提供了新的思路。植物修复技术包括植物萃取、植物固定、植物降解、植物促进、根滤作用和利用植物去除大气污染物等类型。成本低廉、环境友好是该技术的优势,但修复周期长、污染物的生物有效性和毒性水平也限制了其应用。已知的大多数超富集植物生长缓慢、生物量小,是制约植物修复技术应用的瓶颈。为进一步提高植物修复技术的效率,未来研究应侧重于以下几个方向:分子生物学和基因工程技术在超累积植物品种培育中的应用,农事操作对植物修复技术的辅助作用,植物微生物联合修复技术在污染物吸收、转移和降解中的作用机制及应用,以及生物、物理和化学等多种修复措施的综合利用,同时开展大规模的田间验证试验,将植物修复与景观建设、生物质能利用以及观赏植物种苗生产相结合。     

植物对镉毒害的形态和生理响应研究进展

Cadmium (Cd) contamination has posed an increasing challenge to environmental quality and food security.In recent years,phytoremediation has been particularly scrutinized because it is cost-effective and environmentally friendly,especially the use of metal-hyperaccumulating plants to extract or mine heavy metals from polluted soils.Under Cd stress,responses of hyperaccumulator and non-hyperaccumulator plants differ in morphological responses and physiological processes such as photosynthesis and respiration,uptake,transport,and assimilation of minerals and nitrogen,and water uptake and transport,which contribute to their ability to accumulate and detoxify Cd.This review aims to provide a brief overview of the recent progresses in the differential responses of hyperaccumulator and non-accumulator plants to Cd toxicity in terms of growth and physiological processes.Such information might be useful in developing phytoremediation technology for contaminated soils.     

植物修复金属污染土壤上丛枝菌根真菌与植物之间的交互作用

Metal contamination in the environment is a global concern due to its high toxicity to living organisms and its worldwide distribution.The principal goal of this review is to examine the current strategies and technologies for the remediation of metalcontaminated soils by metal-accumulating plants and assess the roles of arbuscular mycorrhizal(AM)fungi in remediation of soils under hyperaccumulator or non-accumulator plants.The use of plants to remove metals from the environment or reduce the toxicity,known as phytoremediation,is an environmentally sustainable and low cost remediation technology.The mechanisms of the use of hyperaccumulator plants for phytoremediation included solubilization of the metal in the soil matrix,the plant uptake of the metal,detoxification/chelation and sequestration,and volatilization.Recently,some ecologists have found that phytoremediation with the aids of mycorrhizae can enhance efciency in the removal of toxic metals.AM fungi can facilitate the survival of their host plants growing on metal-contaminated land by enhancing their nutrient acquisition,protecting them from the metal toxicity,absorbing metals,and also enhancing phytostabilization and phytoextraction.Such information may be useful for developing phytoremediation program at metal-contaminated sites.     

Placing land degradation and biological diversity decline in a unified framework: Methodological and conceptual issues in the case of the north Mediterranean region

The development of synergies between efforts to mitigate land degradation and biological diversity decline can enhance effectiveness, speed up implementation and avoid potential conflicts. Due to the variable nature of these processes and to the variable characteristics of the areas where they occur, there is no general rule linking land degradation and biological diversity decline. Thus, a geographically limited approach focusing on drivers of change may provide a more appropriate base upon which synergies can be built. This exercise is undertaken for the case of northern Mediterranean. Three related processes are discussed: land use change (in the form of agricultural abandonment and intensification, as well as urbanization), wildfires and overuse of freshwater resources. Agricultural abandonment stands out as it may or may not have adverse effects on land resources and it may promote either a reduction in biological diversity or a shift in community synthesis. Agricultural intensification affects adversely both biological diversity and land resources, though often through different mechanisms. Urbanization, by taking up space, wildfires, if they recur in short intervals or they are very extended spatially, and overuse of freshwater resources adversely affect both issues through common mechanisms. The fact that the various drivers may operate through different mechanisms and sometimes they do not even produce consistently positive or negative results calls for a site‐specific understanding of the mechanisms. As many of the processes generating these patterns are not reversible, e.g. intensification of agriculture or tourism growth, ways should be sought to reconcile them with conservation. Copyright © 2010 John Wiley & Sons, Ltd.     

基于耦合模型的重金属污染土壤植物修复效益空间差异分析

在污染土壤生态修复的同时须兼顾其经济、社会效益,以提高其修复综合效益并推动修复工作的顺利开展。以贵溪市为研究区域,使用耦合模型对污染土地植物修复效益进行空间差异评价并筛选适宜的修复植物类型。研究结果显示:研究区域重金属污染土壤植物修复综合效益存在较大空间差异,其中水泉区重金属污染土壤植物修复效益最低为0.173 6,苏门区重金属污染土壤植物修复效益最高为0.835 4;九牛岗区和庞源区效益相近,效益值小于0.4,属于效益较低区块;在种植植物类型上看,混合种植的树木和乔灌木植物,能产生较好的效益,单纯种植一种植物类型,总体效益低;建议将高效益的苏门区植物类型和种植方式进行推广,并采用红叶石楠和栾树间套种植方式。     

土壤中有机污染物的植物修复研究进展

植物修复是土壤有机污染物修复的有效途径之一，主要包括植物吸收、根际土壤酶促进降解和微生物对其的一系列降解。本文简述了植物修复的含义，系统综述了植物修复有机污染物的机理，并阐述了利用植物对农药、氯代化合物、多环芳烃和其它有机污染物进行修复的研究成果与应用，展望了今后进一步研究的重点。     

Problems and prospects concerning the phytoremediation of heavy metal polluted soils: A review

The current state, problems, and prospects of phymoremediation of heavy metal polluted soils are analyzed. The main attention is paid to the phytoextraction and phytostabilization as the most widespread and alternative methods of soil phytoremediation. The efficiency of phymoremediation is related to the natural capability of plants for the accumulation and translocation of metals, their tolerance to a high content of metals, the plant biomass, and the amendments applied. The advantages and disadvantages of phytoremediation as compared to other methods of remediation of polluted soils in situ are considered. Examples of successful phytoextraction and phytomining for cleaning up of contaminated soils in Rasteburg (South Africa) and the phytostabilization of technogenic barrens nearby the copper-nickel plants in Sudbury (Ontario, Canada) and in the Kola Subarctic (Russia) are presented.     

Hydrocarbon degradation potential and activity of endophytic bacteria associated with prairie plants

Phytoremediation systems for organic compounds such as petroleum hydrocarbons rely on a synergistic relationship between plants and their root-associated microbial communities. To determine the probable role of endophytic bacterial communities in these systems, this study examined both rhizosphere and endophytic communities of five different plant species at a long-term phytoremediation field site. Hydrocarbon degradation potential and activity were assessed using MPN assays, PCR analysis of catabolic genes associated with hydrocarbon degradation, and mineralization assays with C-14 labeled hydrocarbons. Microbial community structure in each niche was assessed by DGGE analysis of 16S rRNA gene fragments and subsequent band sequencing. Both endophytic degrader populations and endophytic degrader activity showed substantial inter-species variation, largely independent of that shown by the respective rhizosphere populations. Endophytic hydrocarbon degradation was linked to dominant bacterial endophytes. Pseudomonas spp. dominated endophytic communities exhibited increased alkane hydrocarbon degradation potential and activity, while Brevundimonas and Pseudomonas rhodesiae dominated endophytic communities were associated with increased PAH degradation potential and activity. In one plant species, Lolium perenne, increased endophytic alkane hydrocarbon degradation was associated with increased rhizosphere alkane degradation and decreased rhizosphere PAH degradation. Our results show that diverse plant species growing in weathered-hydrocarbon contaminated soil maintain distinct, heterogeneously distributed endophytic microbial populations, which may impact upon the ability of plants to promote the degradation of specific types of hydrocarbons.     

Rationale and methods for compiling an atlas of desertification in Italy

This study presents the main results and the methodology used in the creation of the atlas of the risk of desertification in Italy. A desertified area was defined as an unproductive area for agricultural or forestry use, due to soil degradation processes. An area at risk of desertification was a tract of the earth's surface which is vulnerable or sensitive to the processes of desertification. In a vulnerable land, environmental characteristics are close to that of a desertified area, but some factors (e.g. vegetation cover or irrigation), successfully mitigate the desertification process. On the other hand, sensitive land is a surface where the process leading to desertification is active, although the land is not yet unproductive. The DPSIR (Driving force‐Pressure‐State‐Impact‐Response) framework has been adopted as a reference. Using the national soil information system and socio‐economic layers, an atlas of indicators of desertification risks was created, which was organized into different soil degradation systems. 51.8 per cent of Italy was considered to be at potential risk of desertification. Some 21.3 per cent of Italy (41.1 per cent of the area at potential risk) featured land degradation phenomena. Specifically, 4.3 per cent of Italy is already unproductive; 4.7 per cent is sensitive and 12.3 per cent is vulnerable. In the territory at potential risk of desertification, unproductive lands, plus areas vulnerable or sensitive to soil erosion, are at least the 19 per cent. Areas affected by aridity also sum up to 19 per cent. Salt‐affected soils in Italy are estimated to cover >1 million ha. Irrigation can mitigate soil aridity and salinization, nevertheless, only about 15 per cent of the sensitive and vulnerable lands of southern Italy are actually equipped with irrigation networks. Copyright © 2009 John Wiley & Sons, Ltd.     

Amaranthus Tricolor Has the Potential for Phytoremediation of Cadmium‐Contaminated Soils

Phytoremediation is a developing technology that uses plants to clean up pollutants in soils. To adopt this technology to cadmium (Cd)–contaminated soils efficiently, a Cd hyperaccumulator with fast growth rate and large biomass is required. In the present study, we selected Caryophyllales as a potential clade that might include Cd hyperaccumulators because this clade had a high mean concentration of zinc (Zn), which is in the same element group as Cd. Three species in Caryophyllales and three species in different clades were grown with Cd. Among them, Amaranthus tricolor showed high accumulating ability for Cd under both water‐culture and soil‐culture conditions, whereas Brassica juncea, a known Cd hyperaccumulator, accumulated high concentrations of Cd in shoots only under water‐culture conditions. This result suggests that A. tricolor has Cd‐solubilizing ability in rhizosphere. Because A. tricolor has large biomass and high growth rate, this species could be useful for phytoremediation of Cd‐contaminated fields.     

Uptake of veterinary medicines from soils into plants

Medicines play an important role in the treatment and prevention of disease. Whereas the side effects on human and animal health resulting directly from treatment have been widely documented, only recently have the occurrence and fate of medicines in the environment and the potential consequences for human health been recognized as an issue warranting consideration. Medicines have been shown to be released to soils and to persist in the environment. This study was performed to investigate the potential for a range of veterinary medicines to be taken up from soil by plants used for human consumption and to assess the potential significance of this exposure route in terms of human health. Soil analyses indicated that, for selected substances, measurable residues of these are likely to occur in soils for at least 5 months following application of manure containing these compounds. Experimental studies on the uptake of veterinary medicines into carrot roots (tubers) and lettuce leaves showed that only florfenicol, levamisole, and trimethoprim were taken up by lettuces, whereas diazinon, enrofloxacin, florfenicol, and trimethoprim were detected in carrot roots. Measured concentrations in plant material were used to model potential adult human exposure to these compounds. Although exposure concentrations were appreciable in a few instances, accounting for approximately 10% of the acceptable daily intake values (ADI), all were lower than the ADI values, indicating that, at least for compounds with properties similar to those considered here, there is little evidence of an appreciable risk. This exposure route may, however, be important when veterinary medicines have a very low ADI, at which they elicit subtle effects over prolonged periods, or when exposure is occurring via a number of routes at once. Although degradation products (produced in the soil or the plant) were not measured, it is possible for some substances that these could increase the risks to consumers.     

转基因植物修复重金属污染土壤研究进展

通过基因工程技术提高植物对金属的耐性,增加金属在植物体内的累积被认为是进行污染土壤生态恢复以及减少食物链金属污染的一条切实可行的有效途径。随着细胞和分子水平上对金属在植物体内的新陈代谢机理的认识及相关基因的不断鉴定,应用转基因技术提高植物对重金属的耐性和积累量的研究已取得了一些进展。本文就近年来分子水平上植物体内金属新陈代谢机理及基因技术在植物修复重金属污染方面的研究进展进行综述。