Phytoremediation is a site remediation strategy, which employs plants to remove non-volatile and immisible soil contents. This sustainable and inexpensive process is emerging as a viable alternative to traditional contaminated land remediation methods. To enhance phytoremediation as a viable strategy, fast growing plants with high metal uptake ability and rapid biomass gain are needed. This paper provides a brief review of studies in the area of phytoaccumulation, most of which have been carried out in Europe and the USA. Particular attention is given to the role of phytochelators in making the heavy metals bio-available to the plant and thier symbionts in enhancing the uptake of bio-available heavy metals.

Field trials were undertaken to investigate the effect of the application of metal mobilizing agents, different sowing strategies and length of growing season on the extraction of Cd and Zn from soils by Thlaspi caerulescens and Arabidopsis halleri. None of the mobilizing agents used enhanced metal accumulation by T. caerulescens. Between 1998 and 2000, on average across plots where Cd or Zn exceeded allowable limits, T. caerulescens removed 1.3 and 0.3% of the total soil Cd and Zn. In one season when T. caerulescens was grown for 14 months, 21.7 and 4.4% of the total soil Cd and Zn was removed. This was larger than values found when T. caerulescens was grown for 4 months. A. halleri accumulated similar concentrations of Zn, but lower Cd concentrations than T. caerulescens. The results indicate that metal phytoextraction using T. caerulescens can be used to clean up soils moderately contaminated by Cd.

Phytoextraction has shown great potential as an alternative technique for the remediation of metal contaminated soils. The objective of this study was to investigate cadmium (Cd) phytoextraction ability of high biomass producing weeds in comparison to indicator plant species. The pot study conducted with 10 to 200 mg Cd kg 1 soil indicated that Ipomoea carnea was more effective in removing Cd from soil than Brassica juncea. Among the five species, B. juncea accumulated maximum Cd, but I. carnea followed by Dhatura innoxia and Phragmytes karka were the most suitable species for phytoextraction of cadmium from soil, if the whole plant or above ground biomass is harvested. In the relatively short time of this experiment, I. carnea produced more than 5 times more biomass in comparison to B. juncea. There were significant differences ( p < 0.05) between the shoot length and shoot mass of control and treated plants.

Three metal-resistant and plant growth-promoting bacteria (Burkholderia sp. GL12, Bacillus megaterium JL35 and Sphingomonas sp. YM22) were evaluated for their potential to solubilize Cu2 (OH)2CO3 in solution culture and their plant growth promotion and Cu uptake in maize (Zea mays, an energy crop) grown in a natural highly Cu-contaminated soil. The impacts of the bacteria on the Cu availability and the bacterial community in rhizosphere soils of maize were also investigated. Inductively coupled-plasma optical emission spectrometer analysis showed variable amounts of water-soluble Cu (ranging from 20.5 to 227mgL 1) released by the bacteria from Cu2 (OH)2CO3 in solution culture. Inoculation with the bacteria was found to significantly increase root (ranging from 48% to 83%) and above-ground tissue (ranging from 33% to 56%) dry weights of maize compared to the uninoculated controls. Increases in Cu contents of roots and above-ground tissues varied from 69% to 107% and from 16% to 86% in the bacterial-inoculated plants compared to the uninoculated controls, respectively. Inoculation with the bacteria was also found to significantly increase the water-extractive Cu concentrations (ranging from 63 to 94%) in the rhizosphere soils of the maize plants compared to the uninoculated controls in pot experiments. Denaturing gradient gel electrophoresis and sequence analyses showed that the bacteria could colonize the rhizosphere soils and significantly change the bacterial community compositions in the rhizosphere soils. These results suggest that the metal-resistant and plant growth-promoting bacteria may be exploited for promoting the maize (energy crop) biomass production and Cu phytoremediation in a natural highly Cu-contaminated soil.

Remediation of soil pollution is one of the many current environmental challenges. Anthropogenic activity has resulted in the contamination of extended areas of land, the remediation of which is both invasive and expensive by conventional means. Phytoextraction of heavy metals from contaminated soils has the prospect of being a more economic in situ alternative. In addition, phytoextraction targets ecotoxicologically the most relevant soil fraction of these metals, i.e. the bioavailable fraction. Greenhouse experiments were carried out to evaluate the potential of four high biomass crop species in their potential for phytoextraction of heavy metals, with or without with the use of soil amendments (EDTA or EDDS). A calcareous dredged sediment derived surface soil, with high organic matter and clay content and moderate levels of heavy metal pollution, was used in the experiments. No growth depression was observed in EDTA or EDDS treated pots in comparison to untreated controls. Metal accumulation was considered to be low for phytoextraction purposes, despite the use of chelating agents. The low observed shoot concentrations of heavy metals were attributed to the low phytoavailability of heavy metals in this particular soil substrate. The mobilising effects induced by EDTA in the soil were found to be too long-lived for application as a soil amendment in phytoextraction. Although EDDS was found to be more biodegradable, higher effect half lives were observed than reported in literature or observed in previous experiments. These findings caution against the use of any amendment, biodegradable or otherwise, without proper investigation of its effects and the longevity thereof.

目前我国农田遭受中低度镉污染的情况日益严重。蓖麻(Ricinus communis L.)是一种能源作物，同时对镉有较高的耐性和富集能力，因此利用蓖麻资源为合理利用镉污染农田提供了一种可行的途径。本论文研究镉胁迫下不同蓖麻品种的耐性和富集特征、筛选高富集型蓖麻品种、矿质营养元素与镉富集的相关性、不同富集能力蓖麻品种的解毒机理差异、不同类型螯合剂调控下蓖麻对镉的富集及根际和非根际镉的形态变化、评估不同种植模式和螯合剂调控下蓖麻对镉的修复效率。试验结果如下:　　(1)低镉(2.396 mg/kg)和高镉(5.396 mg/kg)处理下（盆栽），30种蓖麻品种的地上...

Two species of sunflower, i.e., Tithonia diversifolia and Helianthus annuus , were investigated for their potential to remove heavy metals from contaminated soils. Dried and mature T. diversifolia (Mexican flower) seeds were collected along roadsides, while H. annuus (sunflower) seeds were sourced from the Department of PBST, University of Agriculture Abeokuta, Nigeria. The contaminants were added as lead nitrate (Pb (NO 3 ) 2 ) and zinc nitrate (Zn (NO 3 ) 2 ) at 40002mg/kg which represents upper critical soil concentration for both Pb and Zn. The results indicated that T. diversifolia mopped up substantial concentrations of Pb in the above-ground biomass compared to concentrations in the roots. The concentrations in the leaf compartment were 87.3, 71.3, and 71.502mg/kg at 4, 6, and 802weeks after planting (AP), respectively. In roots, it was 99.402mg/kg, 97.402mg/g, and 77.702mg/kg while 79.3, 77.8, and 60.702mg/kg were observed in the stems at 4, 6, and 802weeks AP, respectively. Observations with H. annuus followed the pattern found with T. diversifolia, showing significant ( p 65<650.05) accumulation of Pb in the above-ground biomass. Results obtained from Zn contaminated soils showed significant ( p 65<650.05) accumulation in the above-ground compartments of T. diversifolia and H. annuus compared with root. However, the highest accumulation of Zn was observed in the leaf. The translocation factor and enrichment coefficient of Pb and Zn with these plant species are greater than 1, indicating that these metals moved more easily in these plants. However, this result also showed that the translocation of Zn from root to the shoot of the two plants was higher than Pb. In conclusion, this experiment showed that these plants accumulated substantial Pb and Zn in their shoots (leaf and stem) at 402weeks AP which diminished with time. This implies that the efficiency of these plants in cleaning the contaminated soils was at the early stage of their growth.

The failure of a tailing pond dam at the Aznalcóllar pyrite mine (SW Spain) in April 1998 released a toxic spill affecting approximately 4300 ha along the Agrio and Guadiamar valleys. Two years later, we have studied yield and concentration of mineral nutrients and trace elements in sunflower plants grown in the spill-affected soil, and in an adjacent unaffected soil as comparison. The study has been carried out in plants at seedling (V4) and mature (R8) stages. Shoot and root biomass of sunflower seedlings was significantly smaller in the affected soil than in the unaffected soil, but there was no significant difference at the mature stage. Oil production was greater in the spill-affected plants. We have not detected any ‘fertilising’ effect caused by the acid waters of the spill on the main nutrient (N, P and Ca) acquisition, as documented in 1998 for sunflower plants flooded by the spill. Sunflower plants growing in the spill-affected soil reached adequate levels of nutrients. None of the trace elements measured—As, Cd, Cu, Pb and Tl—reached levels either phytotoxic or toxic for humans or animals in seeds and the above-ground part of the spill-affected plants. We evaluate the potential use of sunflower plants for phytoremediation. The potential for phytoextraction is very low; however, it may be used for soil conservation. The production of oil (usable for industrial purposes) may add some value to this crop.

The effects of different concentrations of copper sulfate on the growth of and the accumulation of Cu 2+ by root, hypocotyl, cotyledon and leaf growth of sunflower ( Helianthus annuus L.) were examined in this study. The concentrations of copper sulfate ( CuSO 4 · 5 H 2 O) used were in the range from 10 615 to 10 613 M. Seedlings exposed to 10 615 M Cu 2+ solution exhibited a 33% increase in growth ( P<0.005) when compared with the root length of the control. The seedlings treated with 10 613 M Cu 2+ were significantly inhibited in shoot growth ( P<0.005). The Cu 2+ content in roots, hypocotyls, cotyledons and leaves increased with increasing solution Cu 2+ concentration. The roots of plants exposed to 10 613 M Cu 2+ accumulated a large amount of Cu (1070 μg/g DW), and the Cu 2+ level was approximately 25 fold higher than that of control. The Cu 2+ contents in sunflower roots treated with 10 614 and 10 615 M Cu 2+ were about 3.3 and 2.6 fold higher than the control, respectively. Also, the Cu 2+ level of the roots exposed to 10 613 M Cu 2+ was approximately 7.7 and 9.8 fold respectively, in comparison with the roots of plants grown in 10 614 and 10 615 M Cu 2+. At 10 613 M Cu 2+, the Cu accumulated mainly in the roots (about 73%), and small amounts of Cu 2+ (27%) were translocated to the hypocotyls, cotyledons and leaves. The Cu 2+ concentration in the roots was less than that of the above parts of seedlings in treated groups with 10 615–10 614 M Cu 2+. H. annuus has potential ability to accumulate Cu without being overly sensitive to Cu toxicity.

Cadmium (Cd) is a very toxic metal in soils, contaminating agricultural crops due to its absorption by roots. Among crops, sunflower (Helianthus annuus L.) accumulates relatively high amounts of Cd. This work examined the variability of Cd and zinc (Zn) in shoots of sunflower cultivars and investigated if the variability was linked to the shoot growth, to the metal uptake and to the metal partitioning aboveground. Fourteen cultivars of sunflower were cultivated in a nutrient solution containing 20nM of Cd(NO3)2 and 760nM ZnSO4. The between-cultivar variability for the total Cd and Zn content in root and shoot biomass was determined at the 6 8 leaf stage and possible correlations with the biomass and root architecture were investigated. Cd and Zn concentrations in shoots differed between cultivars by a factor of 2.3 and 2.2, respectively. Metal uptake was more positively correlated with shoot biomass than with root biomass and was not correlated with root architecture. The between cultivar differences for metal concentration in shoots was explained by differences in uptake relative to shoot growth and for Cd, by the partitioning of the metal between roots and shoots. This study suggests that Cd root uptake relative to shoot growth and Cd partitioning to shoots could be targets for selecting cultivars having a low (for crop quality) or a high (for phytoextraction) Cd content aboveground.

植物修复技术被认为是治理重金属污染最为绿色的方法，因为此技术成本低、实施方便、无污染。超富集植物的研究是重金属污染植物修复的重点，然而一种植物由具有富集重金属特性到应用于现实的重金属污染修复并非易事。研究表明，在现实条件下，植物修复技术应用于治理土壤重金属污染中存在一些约束。本文系统地总结了目前超富集植物的研究方法和研究现状，通过分析超富集植物在现实条件下修复土壤重金属污染的不足，提出土壤重金属污染植物修复的方向。

遏蓝菜Thlaspi caerulescens可以在其地上部累积大量重金属如锌、镉等，是公认的超富集植物。由于该植物生物量小，不宜直接用于重金属污染的土壤植物修复，而被广泛作为一种模式植物来进行重金属富集机制研究。遏蓝菜对重金属离子的累积大致经过螯合剂解毒、地上部长距离运输以及在液泡中的储存等生理过程。已经发现的植物体内的金属螯合剂——有机酸、氨基酸、植物络合素(PCs)、金属硫蛋白(MT) 和尼克烟酰胺NA等，区室化以及长距离运输相关的转运蛋白——ZIP (ZRT/IRT like protein)、CDF (Cation diffusion facilitator)、Nramp (Natural resistance and macrophage protein) 和HMA (Heavy metal ATPase) 等家族，以上各种基因、多肽与蛋白等共同参与了植物对金属累积与耐受过程并发挥各自重要的作用。以下主要介绍了遏蓝菜重金属超富集相关的基因、多肽和蛋白，以及它们在重金属螯合作用和运输过程中的功能。

OAc-extractable Zn and Cd concentrations were significantly reduced in planted soils compared to unplanted soils. Microbial biomass C (C), basal respiration and microbial quotient (M) were significantly and positively correlated and soil metabolic quotient (CO) was negatively correlated with heavy metal concentrations in unplanted soils ( , basal respiration and M values increased significantly after phytoremediation by five crops over two years compared to unplanted soil. Urease, -glucosidase, neutral phosphatase and arylsulfatase activities also increased significantly with decreasing heavy metal contents and hydrolase activity was enhanced in planted soil ( S. plumbizincicola to extract Zn and Cd from contaminated soil and also that phytoremediation had beneficial effects on soil microbial and hydrolase activities, with the metal phytoextraction procedure restoring soil quality.

镉作为一种毒性较强的重金属污染物,由于长期施用磷肥、金属电镀和塑料工业发展等原因而在农田长时间残留,对人类健康造成潜在的威胁。针对目前日益严重的镉污染,植物修复是一种绿色廉价、被人们广泛认可的有效的原位治理措施,其核心技术在于利用极少数镉超富集植物来去除土壤中的镉以达到修复和治理环境的目的。本文以新型镉超富集植物龙葵为研究对象,通过营养液培养方法

Recently, researchers are becoming interested in using hyperaccumulators for decontamination of heavy metal polluted soils, whereas few species that hyperaccumulate cadmium (Cd) has been identified in the plant kingdom. In this study, the physiological mechanisms at the seedling stage and growth responses and Cd uptake and accumulation at flowering and mature stages of Bidens pilosa L. under Cd treatments were investigated. At the seedling stage, when soil Cd was lower than 16 mg kg 611, the plant did not show obvious symptom of phytoxicity, and the alterations of chlorophyll (CHL), superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA), and soluble protein (SP) did not have significant differences when compared with the control. At the flowering and mature stages, under low Cd treatments (≤16 mg kg 611), the application of Cd could facilitate plant growth, resulting in 3.9–11.0% and 5.9–13.8%, respectively, increase in shoots dry biomass compared with the control. The Cd concentrations in stems, leaves and shoots exceeded 100 mg kg 611 when soil Cd was at 8 mg kg 611, and they were positively correlated with Cd concentration in soils, the bioaccumulation factor (BF) and translocation factor (TF) values were all greater than 1.0. Thus, it is clear that B. pilosa has the basic characteristics of a Cd-hyperaccumulator. All the results elementarily indicated that B. pilosa is a potential Cd-hyperaccumulating plant.

长期以来重金属超富集植物定义存在着严重的不足,新的评价系数的提出势在必行。文章在生物富集系数和转运系数的基础上创造性地提出了新的评价系数即生物富集量系数,其内涵为给定生长期内单位面积地上部分植物吸收的重金属总量与土壤含量之比。此系数的提出扩大了传统超富集植物的定义,使得富集质量分数未达某一水平,但生物量很大的植物也能作为超富集植物。这为今后超富集植物的筛选提供了一定的参考,为土壤重金属污染的植物修复工程提供了理论基础。

Hemp ( Cannabis sativa L.) was used to examine its capability as a renewable resource to decontaminate heavy metal polluted soils. The influence of heavy metals on the fibre quality was of special interest. Determination of heavy metal content was carried out by means of atomic absorption spectroscopy (AAS). Four different parts of the plant were examined: seeds, leaves, fibres and hurds. In each case, the concentration relation was Ni>Pb>Cd. However, the heavy metal accumulation in the different parts of the plant was extremely different. All parts of hemp plants contain heavy metals and this is why their use as a commercially utilisable plant material is limited. We found that the highest concentrations of all examined metals were accumulated in the leaves. In this field trial, hemp showed a phytoremediation potential of 126 g Cd (ha vegetation period) 1. We tested the fibre quality by measuring the pure fibre content of the stems and the fibre properties after mechanical separation. In addition, the fibre fineness was examined using airflow systems and image analysis. The strength was measured by testing single fibre bundles with a free clamping distance of 3.2 mm using a universal testing device. Finally, we compared the results from the stems and fibres from trials on heavy metal polluted ground with hemp stems and fibres from non-polluted ground. Since there was no comparable unpolluted area near the polluted one, reference values were taken from an area quite far away and subsequently with a different soil composition and also exposure to different meteorological conditions. Thus, the observed differences are only partially caused by the heavy metal contamination.

61Metal content in ash reflects the element concentrations in Phragmites australis and Arundo donax.61Metal enriched ash of both species may be recycled as fertilizers in agriculture and forestry.61Constructed wetlands may produce a large amount of plant ash-based fertilizers from P. australis and A. donax.

Cadmium (Cd) and dichlorodiphenyltrichloroethane (DDT) or its metabolite residues are frequently detected in agricultural soils and food, posing a threat to human health. The objective of this study was to compare the ability of 23 genotypes of Ricinus communis in mobilizing and uptake of Cd and DDTs (p,p′-DDT, o,p′-DDT, p,p′-DDD and p,p′-DDE) in the co-contaminated soil. The plant genotypes varied largely in the uptake and accumulation of DDTs and Cd, with mean concentrations of 0.37, 0.43 and 70.51 for DDTs, and 1.22, 2.27 and 37.63mgkg611dw for Cd in leaf, stem and root, respectively. The total uptake of DDTs and Cd varied from 83.1 to 267.8 and 66.0 to 155.1μg per pot, respectively. These results indicate that R. communis has great potential for removing DDTs and Cd from contaminated soils attributed to its fast growth, high biomass, strong absorption and accumulation for both DDTs and Cd.

选取油脂类能源植物大豆和碳水化合物类能源植物玉米,采用高通量测序方法研究大豆、玉米修复Cd污染土壤过程中根际土壤细菌群落组成.结果表明,100 mg·kg-1Cd的添加会抑制玉米、大豆生长,其中,大豆生物量降低比玉米高.不同组织中根部Cd积累量最高,转移系数TF分别为0.56(玉米)和0.14(大豆).基于Mi Seq的群落分析表明,大豆、玉米根际土壤细菌主要包括Proteobacteria(变形菌门)、Acidobacteria(酸杆菌门)、Gemmatimonadetes(芽单胞菌门)、Actinobacteria(放线菌门)、Bacteroidetes(拟杆菌门)等33个门.细菌群落的PCo A和UPGMA分析表明,Cd的添加和能源植物种植均能对细菌群落结构产生影响,其中,Cd的添加影响最大.Gemmatimonas、Flavisolibacter、Flexibacter、Ramlibacter、Ohtaekwangia、Flavitalea等细菌在Cd胁迫条件或大豆、玉米种植条件下相对丰度有所变化,分析其可能在大豆、玉米耐受Cd污染中起作用.

田间试验、温室盆栽和生长室水培试验研究了Zn和Cd超富集植物伴矿景天不同叶龄叶片的Zn、Cd富集和分布特征。结果显示,田间条件下伴矿景天新叶中Cd浓度高于成熟叶、但新叶中Zn浓度低于成熟叶。温室盆栽试验发现,连续种植伴矿景天,第4季时低污染土壤（S1）上新叶中Zn浓度低于成熟叶,但高污染土壤（S4）上新叶中Zn浓度高于成熟叶;而到了第6季,S1、S4上新叶中Zn浓度均低于成熟叶,且在S1上两者达到显著水平;第4和第6季,伴矿景天新叶中Cd浓度始终高于成熟叶（除S1成熟叶中Cd浓度略高于新叶外）。水培试验结果发现,无论在高Zn（600μmol/L）、高Cd（100μmol/L）,还是低Zn（10μmol/L）、低Cd（1μmol/L）处理,新叶中Zn、Cd浓度均高于成熟叶;而且随着处理时间的延长,新叶和成熟叶中Zn、Cd浓度均明显上升。水培条件下,新叶和成熟叶中Zn最高分别为43107、33774mg/kg（以干重计）（600μmol/L,处理56天）;新叶和成熟叶中Cd的最高浓度分别为15057、9060mg/kg（以干重计）（100μmol/LCd,处理56天）。这些结果表明,Zn、Cd在伴矿景天新叶和成熟叶中富集和分布与其生长介质中Zn、Cd的浓度尤其是有效态浓度、处理时间及植物所处的生长阶段等有关,同时也表明Zn、Cd优先分布于新叶可能与伴矿景天超富集Zn、Cd的机制有关。

当今土壤重金属污染日趋严重,植物修复技术以其成本低、环境友好以及不引起二次污染等优势,已引起国际社会的广泛关注。可以说植物修复技术有着广阔的应用前景,但由于目前对植物重金属超积累认识的不足限制了该技术的改进和应用。东南景天(Sedum alfredii Hance)作为一种我国原生的锌镉超积累植物和铅富集植物,被认为是植物修复的良好材料。根系分泌物是植物响应外界环境胁迫最直接的反应,超积累植物根系分泌物的研究对于提高植物修复效率有着重要的意义。本研究以两种生态型的东南景天为研究材料,采用溶液培养的方法,运用高效液相色谱、离子色谱、电感耦合等离子质谱等分析技术,建立了东南景天根系分泌物的分析检测方法,比较系统地研究了东南景天根系分泌特性,取得主要研究结果如下： 1.建立了适合东南景天根系分泌物收集分离并测定其中主要有机酸和氨基酸的方法。以两种生态型东南景天为原材料,采用营养液培养,以0.5mM CaCl2溶液收集植物根系分泌物,运用阴、阳离子交换柱层析法以及固相萃取法对根系分泌物中有机酸和氨基酸组分进行有效分离和纯化,综合运用反相色谱法、反相离子对色谱法以及离子色谱法进行根系分泌物中有机酸和氨基酸组分的定性和定量分析。同时又将该方法拓展用于东南景天根、茎、叶中的有机酸和氨基酸的分析。两种生态型东南景天根系分泌物中有机酸和氨基酸组成基本一致,但含量存在显著差异。分泌物有机酸组成为大量的草酸、酒石酸、乳酸,以及少量的苹果酸、柠檬酸、延胡索酸；氨基酸组成为18种蛋白氨基酸以及γ-氨基丁酸、鸟氨酸等非蛋白氨基酸。两种生态型东南景天根、茎、叶中有机酸组成基本一致,主要有草酸、酒石酸、苹果酸、乳酸、柠檬酸、延胡索酸,以及少量乙酸、琥珀酸、丙酸,但含量存在显著差异。 2.在Zn/Cd/Pb三种不同重金属处理下,两种生态型东南景天根系分泌物pH值均显著降低(P0.05)。普遍的根系分泌物酸性HE型较NHE型更大,而不同重金属之间,Pb胁迫下根系分泌物酸性最强,其次是Zn胁迫下,而Cd胁迫下分泌物酸性相对较弱,这与Zn/Cd/Pb三种重金属在营养液中的形态以及各自的生物毒性都有很大关系。 3.在Zn/Cd/Pb三种不同重金属处理下两种生态型根系分泌物中有机酸和氨基酸的组成基本一致,但分泌量差异显著。重金属Zn胁迫下,两种生态型东南景天草酸、酒石酸、谷氨酸、γ-氨基丁酸分泌量均显著增加,其中酒石酸、谷氨酸、γ-氨基丁酸分泌量HE型显著高于NHE型(P0.05),对Zn胁迫有很强的响应。重金属Pb胁迫下,两种生态型东南景天草酸、柠檬酸、谷氨酸、γ-氨基丁酸分泌量均显著增加,且HE型显著高于NHE型(P0.05),对Pb胁迫有很强的响应。不同重金属胁迫下,两种生态型东南景天草酸的分泌量均显著增加,但两种生态型之间差异不大;两种生态型东南景天苹果酸、延胡索酸的分泌量较低,规律不明显。 4.两种生态型东南景天根系在应对重金属胁迫时,响应速率和根系有机酸和氨基酸分泌速率差异显著(P0.05),HE型较NHE型更快。重金属处理12h,HE型分泌量已经显著增加,而NHE型分泌量增加不多,甚至还出现一定程度降低的情况,NHE型分泌量的显著增加基本出现在处理36h。HE型的这种快速响应机制可能是其特有的,是HE型高重金属耐性以及超积累能力的一种表现。 5.重金属Zn处理下外源添加草酸和γ-氨基丁酸都能增加两种生态型东南景天的生物量,减轻重金属Zn对植物的毒害。γ-氨基丁酸能显著增加东南景天地上部Zn积累量,而草酸却不能(P0.05)。重金属Pb处理下外源添加草酸和γ-氨基丁酸对两种生态型东南景天的影响不同。草酸和γ-氨基丁酸不仅能增加HE型的生物量,而且还能显著增强其地下部Pb的富集能力,γ-氨基丁酸的作用强于草酸(P0.05)。草酸和γ-氨基丁酸不仅不能增加NHE型的生物量,而且还降低其地下部Pb的富集能力(P0.05)。

土壤重金属污染是中国乃至全球所面临的严重环境问题之一,其中镉(Cd)以高毒性和强移动性而备受关注。但现有的Cd超积累植物大多具有生物量小、生长缓慢和地域性强等特点,导致其难以大规模推广和应用。水稻Cd高积累材料是一种较理想的土壤Cd污染修复植物,因其具有生物量大、适应性强和遗传稳定等优势,是Cd污染农田潜在植物修复材料之一。本研究以水稻Cd高积累材料为研究对象,Cd低积累材料为对照,通过土培和水培试验,设置不同Cd处理浓度,研究水稻Cd高积累材料对Cd的积累、生理和耐性响应特征,主要研究结果如下：(1)当Cd处理浓度为20mg·kg-1 (Cd20)时,水稻Cd高积累材料(Lu527-8和Lu17-9)各生育期生物量、Cd含量均显著高于Cd低积累材料(Lu527-4)。Lu527-8和Lu17-9地上部和整株生物量随生育期的延长显著上升,具体表现为拔节期、抽穗期、灌浆期和成熟期上升幅度较大。同时,Lu527-8和Lu17-9地上部和整株生物富集量在灌浆期后趋于稳定,而地上部和整株Cd积累速率在灌浆期达最大值。Lu527-8和Lu17-9地上部和整株Cd积累量在拔节期、抽穗期和灌浆期上升显著且整株阶段性Cd积累量在拔节期-抽穗期和抽穗期-灌浆期分别占整个生育时期的15.30%、40.45%和39.70%、20.74%。Lu527-8和Lu17-9整株净化率在灌浆期时分别达4.88%和4.39%,为Lu527-4的2.44倍和2.21倍。水稻Cd高积累材料具有更强的Cd积累能力,灌浆期为水稻Cd高积累材料的最佳收获时期。(2)随着Cd处理浓度的增加,两类水稻材料可溶部分、细胞壁和细胞器Cd含量均显著上升,其中Lu527-8和Lu17-9亚细胞组分Cd含量显著高于Lu527-4。Lu527-8和Lu 17-9根部亚细胞组分Cd含量表现为可溶部分细胞壁细胞器,茎和叶亚细胞组分Cd含量表现为细胞壁可溶部分细胞器。在Cd20条件下,Lu527-8和Lu17-9叶片Cd含量在细胞壁所占比例最大,拔节期达68.86%和72.44%,灌浆期达67.12%和67.27%。两类水稻材料光合色素含量在拔节期和灌浆期随Cd处理浓度的增加均显著降低,Lu527-8和Lu17-9光合色素含量显著高于Lu527-4。Lu527-8和Lu17-9拔节期叶绿素a含量达1.94和1.88mg·g-1,叶绿素b含量达1.09和1.06mg·g-1,为Lu527-4的1.88倍和1.83倍。Lu527-8和Lu527-4类胡萝卜素含量均显著高于Lu527-4。同时,Cd胁迫增加水稻叶片丙二醛和可溶性糖含量,导致叶片中可溶性蛋白含量显著降低。Lu527-8和Lu17-9叶片丙二醛和可溶性蛋白含量显著高于Lu527-4,其可溶性糖含量则显著低于Lu527-4。表明,水稻Cd高积累材料具备更强的Cd区室化能力、抗氧化能力、光合色素合成能力以及细胞渗透调节能力。(3)Cd胁迫下两类水稻材料细分枝根、粗分枝根和不定根形态均受到不同程度的抑制,Lu527-8和Lu17-9根长、根表面积和根体积均显著高于Lu527-4。随着Cd处理浓度的增加,两类水稻材料根系总吸收表面积和活跃吸收表面积均显著降低。Lu527-8和Lu 17-9根系总吸收表面积达0.40-0.61和0.39-0.62 cm2·plant-1均显著高于Lu527-4。当Cd浓度为10 mg.L-1(Cd10)时,Lu527-8和Lu17-9根系活跃吸收表面积均为0.20 cm2·plant-1,为Lu527-4的2.00倍。同时,两类水稻材料根系氧化力和还原力均随Cd处理浓度的增加显著降低,并且Lu527-8和Lu17-9显著高于Lu527-4。在Cd10条件下Lu527-8和Lu17-9根系氧化力为Lu527-4的1.52倍和1.49倍；根系还原力为Lu527-4的1.28倍和1.31倍。表明,水稻Cd高积累材料具有更强的根系伸展、养分和水分吸收能力。(4)随着Cd处理浓度的增加,两类水稻材料各器官脯氨酸含量均显著上升,表现为茎根叶,Lu527-8和Lu17-9脯氨酸显著高于Lu527-4。Lu527-8口Lu17-9根系脯氨酸含量在Cd10达最大值,非蛋白巯基、谷胱甘肽、植物螯合肽含量均显著高于Lu527-4,并且各器官含量表现为茎根叶；Lu527-8和Lu17-9根系非蛋白巯基含量达7.19和6.85μg·kg-1,为Lu527-4的1.23倍和1.17倍；根系谷胱甘肽含量为3.19和3.03 gg-kg-1,为Lu527-4的1.32倍和1.26倍。当Cd浓度为2(Cd2)和5 mg-L-1(Cd5)时,Lu527-8和Lu17-9根系植物螯合肽含量显著高于Lu527-4。在Cd10条件下,Lu527-8和Lu17-9根系植物螯合肽含量与Lu527-4差异不显著。表明,水稻Cd高积累材料具有更强的PCs合成能力,缓解Cd对植物的毒害。

为从花卉中筛选镉超富集植物用于镉污染土壤的修复,采用土壤高浓度镉污染法从5种花卉植物中筛选出具有镉富集植物基本特征的花卉植物硫华菊,并通过盆栽试验和小区试验,进一步研究硫华菊的镉积累特性。结果表明：随土壤镉浓度的增加,硫华菊的生物量、光合色素含量及可溶性蛋白含量均呈先增后降的趋势,SOD活性、POD活性呈增加的趋势,但CAT活性则呈降低的趋势。镉在硫华菊各个器官中的分布大小顺序为：根系〉茎秆〉地上部分〉叶片。硫华菊根系、茎秆、叶片及地上部镉含量随土壤镉浓度的增加呈增加的趋势,且在土壤镉浓度大于10mg/kg时,硫华菊地上部分镉含量均超过镉超富集植物临界值（100mg/kg）。不同浓度镉处理的硫华菊地上部分镉富集系数（BCF）均大于1,但转运系数（TF）均小于1。硫华菊根系、茎秆、叶片及地上部分镉积累量随土壤镉浓度的增加均呈先增后降的趋势,地上部分镉积累量最大值为479.34μg/株（土壤镉浓度为100mg/kg）。小区试验研究表明,在土壤镉浓度为2.04-2.89mg/kg时,硫华菊地上部分镉积累量为4.54-5.60mg/m^2。因此,硫华菊是一种镉富集植物,且修复能力较强,可有效地修复镉污染土壤。

In order to reveal the historical context of metal element accumulation under the economic boom during the last decades in eastern China, concentrations of nine metal elements, radionuclides (210Pb), Pb isotope ratios (207Pb/206Pb) and sedimentary characteristics were investigated in two sediment cores collected from the Sheyang River. The sediments have recorded the heavy metal deposition and thus allow establishing a connection between the temporal evolution of the heavy metal pollution and historical changes in industrial and urban discharges. Enrichment factors (EFs) were calculated to estimate the level of contamination in these sediments. A significant anthropogenic enrichment of Cu, Ni, Pb, Cr and Zn was highlighted, which were identified from anthropogenic discharges from cities and industrial sources, according to a cluster analysis. According to the annual variation in GDP growth rate, industrial growth rate, ratio of 207Pb/206Pb and EFs, it was obvious that sedimentary accumulation of metals has a close relationship with anthropogenic activities. In the pre-industrial period, natural inputs prevailed with lower EF and constant 207Pb/206Pb ratios around 0.82. However, during 1980鈥1995, the rapid industrial development caused a gradual increase in EFs and 207Pb/206Pb (>0.83). Our results disinterred the evolution of anthropogenic metal inputs in the last century into the Sheyang River.

Phytoextraction and phytostabilization are well-established sub-processes of phytoremediation that are being followed for in situ remediation of soils contaminated with toxic metals. Taraxacum mongolicum Hand-Mazz, a newly reported Cd accumulator has shown considerable potential for phytoextracting Cd. This paper investigated the effects of urea and chicken manure on T. mongolicum phytoextracting Cd from soil using pot culture experiments. The results showed that urea application did not affect the Cd concentrations in root, leaf, inflorescence and shoot of T. mongolicum, but chicken manure significantly decreased them ( p < 0.05) by 23.5%, 31.5%, 24.8% and 30.4% owing to decreased extractable Cd. Urea and chicken manure significantly increased ( p < 0.05) the phytoextraction capacities (μg pot 611) of T. mongolicum to Cd by 3–5-fold due to the increase in shoot biomass (increased 4–7 folds). Further, addition of urea and chicken manure increased organic matter, nitrogen, phosphorus and potassium, the microorganism count, urease and phosphatase activities of soil indicating their eco-friendly function. Urea is ideal for optimizing phytoextraction of T. mongolicum to Cd , while chicken manure is appropriate for phytostabilization.

Phytoremediation with the use of hyperaccumulating plant species to remove excess trace metals from contaminated soil and water is considered a cost-effective non-invasive technique. Over 400 plant ta

We investigated the effects on physiological response, trace elements and nutrients accumulation of sunflower plants grown in soil contaminated with: 5 mg kg611 of Cd; 5 and 300 mg kg611 of Cd and Zn, respectively; 5, 300, and 400 mg kg611 of Cd, Zn, and Cu, respectively. Contaminants applied did not produce large effects on growth, except in Cd-Zn-Cu treatment in which leaf area and total dry matter were reduced, by 15%. The contamination with Cd alone did not affect neither growth nor physiological parameters, despite considerable amounts of Cd accumulated in roots and older leaves, with a high bioconcentration factor from soil to plant. By adding Zn and then Cu to Cd in soil, significant were the toxic effects on chlorophyll content and water relations due to greater accumulation of trace elements in tissues, with imbalances in nutrients uptake. Highly significant was the interaction between shoot elements concentration (Cd, Zn, Cu, Fe, Mg, K, Ca) and treatments. Heavy metals concentrations in roots always exceeded those in stem and leaves, with a lower translocation from roots to shoots, suggesting a strategy of sunflower to compartmentalise the potentially toxic elements in physiologically less active parts in order to preserve younger tissues.

研究螯合剂对向日葵在镉污染土壤下的吸收、转运、富集特性具有重要意义。在每千克土中施用镉的浓度为15 mg/kg,同时分别投加2.5、5.0和7.5 mmol/kg的乙二胺二琥珀酸（EDDS）、草酸（OA）和柠檬酸（CA）,研究了其对向日葵生长、吸收土壤中镉,以及对土壤中镉的活化性能的影响。结果表明：2.5 mmol/kg OA、CA处理下,向日葵生物量略增,其他处理均使向日葵生物量有不同程度的降低。在高浓度螯合剂处理时,降幅最大;在5.0 mmol/kg EDDS处理下,向日葵根部、地上部及单株镉含量最大,分别为92.73、89.15和92.58 mg/kg,是CK的5.51倍、2.34倍及4.45倍;在7.5 mmol/kg EDDS处理下,向日葵的转运系数最高时为1.075,是对照组的1.99倍;土壤镉的活化性最大时为10.96 mg/kg,是对照组的1.42倍。EDDS的添加比OA和CA更显著地增加了土壤镉的活化性,同时显著提高了向日葵的富集系数和转运能力。综合看来,螯合剂的投加能有效活化土壤中的镉,促进植物转运、吸收。

Phytoextraction is a remediation technique that consists in using plants to remove contaminants from soils and water. This study evaluated arsenic (As) accumulation in Castor bean ( Ricinus communis cv. Guarany) grown in nutrient solution in order to assess its phytoextraction ability. Castor bean plants were grown under greenhouse conditions in pots containing a nutrient solution amended with increasing doses of As (0, 10, 50, 100, 250, 500 and 5000 μg L 611) in a completely randomized design with four replications. Shoot and roots dry matter production as well as arsenic and nutrient tissue concentrations were measured at the end of the experiment. The results showed that increasing As concentration in nutrient solution caused a decrease in shoot and root biomass but did not result in severe toxicity symptoms in castor bean growing under a range of As concentration from 0 to 5000 μg L 611. The As doses tested did not affect the accumulation of nutrients by castor bean. Although castor bean did not pose characteristics of a plant suitable for commercial phytoextraction, it could be useful for revegetation of As-contaminated areas while providing an additional income by oil production.

<P><FONT face=Verdana>【目的】苋菜在中国的分布很广，品种资源丰富。通过筛选耐镉苋菜品种，发掘镉污染土壤植物修复资源。【方法】采用溶液培养方法，从来自不同生态区域的23个苋菜品种（Amaranthus mangostanus L.）中筛选出具有镉超富集能力的品种;采用赤红壤、黄棕壤、菜园土进行盆栽试验，研究苋菜在土壤Cd浓度分别为5、10、25 mg?kg-1时，对镉污染土壤的修复潜力。【结果】在溶液Cd浓度3 mg?L-1条件下培养，苋菜品种天星米地上部镉含量高达260 mg?kg-1。在土壤Cd浓度 25 mg?kg-1条件下，苋菜天星米地上部镉浓度高达212 mg?kg-1，富集系数达到8.5，地上部净化率达3.8%，各镉处理水平总生物量以及地上部生物量均未显著降低。【结论】苋菜天星米基本具备了镉超富集植物的特征，可用于镉污染土壤的生物修复。<BR></FONT></P>

Phytoremediation is an in situ, cost-effective potential strategy for cleanup of sites contaminated with trace metals. Selection of plant materials is an important factor for successful field phytoremediation. A field experiment was carried out to evaluate the phytoextraction abilities of six high biomass plants ( Vertiveria zizanioides, Dianthus chinensis , Rumex K-1 ( Rumex upatientia × R. timschmicus ), Rumex crispus , and two populations of Rumex acetosa ) in comparison to metal hyperaccumulators ( Viola baoshanensis , Sedum alfredii ). The paddy fields used in the experiment were contaminated with Pb, Zn, and Cd. Our results indicated that V. baoshanensis accumulated 2802mg kg 611 Cd and S. alfredii accumulated 6,27902mg kg 611 Zn (dry weight) in shoots, with bioconcentration factors up to 4.8 and 6.3, respectively. The resulting total extractions of V. baoshanensis and S. alfredii were 0.1702kg ha 611 for Cd and 32.702kg ha 611 for Zn, respectively, with one harvest without any treatment. The phytoextraction rates of V. baoshanensis and S. alfredii for Cd and Zn were 0.88 and 1.15%, respectively. Among the high biomass plants, R. crispus extracted Zn and Cd of 26.8 and 0.1602kg ha 611 , respectively, with one harvest without any treatment, so it could be a candidate species for phytoextraction of Cd and Zn from soil. No plants were proved to have the ability to phytoextract Pb with high efficiency.

本文主要以经济作物蓖麻(Ricinus communis L.)和向日葵(Helianthus annuus L.)为研究对象,以上海某工业搬迁遗址为试验污染场地,探讨了在野外大田实验条件下,不同生长时期的经济作物对重金属Cd和Zn的吸收富集特征,并据此对比分析了三种不同经济作物对Cd和Zn的修复潜力,从而为植物修复重金属污染土壤的实际应用提供科学依据。主要研究结果如下:(1)试验污染场地的重金属含量情况如下:Zn平均浓度为548.32 mg/kg(146.59~1618.66 mg/kg);Cu平均浓度为46.36 mg/kg(26.74~66.36 mg/kg);Cr平均浓度为116.47 mg/kg(85.31~239.02 mg/kg);Cd平均浓度为1.04 mg/kg(0.50~2.19 mg/kg)。(2)以《展览会用地土壤环境质量评价标准(暂行)》(HJ 350-2007)A级标准限值为参照,对比分析试验污染场地的重金属浓度可知,Cd和Zn是该研究区域土壤主要的污染元素,其中Zn的污染程度更为严重,覆盖范围更广。(3)运用Hakanson潜在生态危害指数法评价试验场地的重金属生态危害特性,各单一重金属的潜在生态危害排序为CdCuZnCr,其中Zn、Cr、Cu对研究区域造成的潜在生态危害程度均为轻微,Cd则为强潜在生态危害,重金属对研究区所形成的综合潜在生态危害为中等。因此,在本实验中选定Zn和Cd作为研究经济作物原位修复重金属污染土壤的重金属元素。(4)由于试验污染场地的重金属污染浓度分布不均,本文采用显著性差异分析的统计学方法对所有样方的重金属浓度进行分析,将试验场地根据重金属污染浓度的高低分为不同的组别,消除土壤重金属污染异质化的影响,从而进一步考察土壤重金属污染浓度对植物生物量、组织器官内重金属浓度和重金属积累量的效应。土壤镉锌复合污染胁迫对蓖麻的生长具有一定的抑制作用,随着生长时间的延长,蓖麻生物量增加的幅度呈现出先上升后下降的趋势。蓖麻根和茎中的Cd浓度随着土壤中Cd浓度的增加表现为先增加后降低,根、茎、叶和果实中Cd浓度梯度整体上为根茎叶果实。蓖麻根和茎中Zn浓度随着生长时间的延长而减小。蓖麻根、茎、叶中Cd和Zn富集量随着生长时间的延长而明显增大,且地上部重金属富集量均高于根部。(5)随着土壤Cd和Zn污染浓度的增加,30天和120天俄罗斯向日葵(Helianthus annuus var.Russian)根、茎、叶和果实中Cd和Zn的浓度均呈现出先增加后降低的趋势,说明当土壤中重金属浓度过高时,会抑制俄罗斯向日葵吸收重金属的能力。在各个生长时期内,俄罗斯向日葵地上部分重金属的浓度和富集量均显著高于根部,表明俄罗斯向日葵易于将根部Cd和Zn向地上部转移,具有一定的植物修复潜力。(6)在普通向日葵(Helianthus annuus var.Chinese)生长时期内,随着土壤Cd和Zn浓度的增加,根、茎、叶和果实中Cd和Zn浓度随之先增加后降低,表明普通向日葵吸收Cd和Zn的能力会受到土壤中过高浓度重金属的抑制。普通向日葵根部和地上部重金属富集量随着生长时间的延长而明显增大,且地上部分重金属富集量均明显高于根部。(7)与蓖麻和普通向日葵相比,俄罗斯向日葵修复Cd和Zn污染场地的潜力和效益均最高。120天时收获俄罗斯向日葵可以去除土壤中Cd达2.03 g/ha,且收获植株中富含50.34 GJ/ha能量。60天时收获俄罗斯向日葵可以去除土壤中Zn 305.08 g/ha,而收获植株用做能源能产生49.6 GJ/ha的热值。因此,选择向日葵这种经济作物作为修复重金属污染场地的修复植物,同时具有一定的修复效果和经济价值。

通过不同浓度的EDTA和柠檬酸对土壤进行处理,强化向日葵修复Cd-Ni复合污染土壤的盆栽试验,分析了向日葵根部和地上部中Cd、Ni的含量,探讨EDTA和柠檬酸进入土壤后对Cd、Ni吸收和运输的影响.试验结果表明:采用向日葵对Cd-Ni复合污染土壤进行修复时,EDTA为2.5mmol·kg-1时,向日葵提取镉的总量达到最大值,EDTA一次加入5.0 mmol·kg-1时,向日葵提取镍的总量达到最大值;柠檬酸加入5.0 mmol·kg-1时,向日葵提取镉的总量达到最大值.柠檬酸分两次加入10.0 mmol·kg-1时,向日葵提取镍的总量达到最大值.

Little information is available concerning the efficacy of chelates applied to biosolids (sewage-sludge)-treated soil for heavy-metal removal. The purpose of the experiment was to determine the availability to sunflower (Helianthus annuus L.) and hybrid poplar (Populus deltoides Marsh. × P. nigra L.) seedlings, of non-essential (Cd, Ni, Pb) and essential heavy metals (Cu, Fe, Mn, Zn) in field soil injected with biosolids since 1976 and treated with ethylenediamine-tetraacetic acid (EDTA) in 2001. Sunflower was grown at two densities, 20000 and 60000 plants/ha, and poplar at 10000 plants/ha. The tetrasodium salt of EDTA was applied at rates of 0, 0.5, 1, and 2 g EDTA salt per kg surface (25-cm depth) soil. The EDTA did not affect uptake by poplar of the three non-essential (Cd, Ni, Pb) and four essential (Cu, Fe, Mn, Zn) heavy metals. For sunflower, the 1.0 g/kg rate of chelate addition resulted in maximal removal of the three non-essential heavy metals (Cd, Ni, Pb). Uptake of the essential heavy metals by sunflower was little affected by the EDTA. At the 20 000 plants/ha density, leaves of sunflower grown with 1.0 g EDTA Na4·2H2O per kg soil accumulated more Cd, Ni, and Pb than leaves of sunflower grown without the EDTA salt. At this density, concentrations of Cd in leaves of sunflower without EDTA and with 1.0 g/kg EDTA salt were 2.2 and 6.5 μg/g, respectively; for Ni, they were 6.7 and 19.2 μg/g, respectively; and for Pb, they were 15.6 and 46.9 μg/g, respectively. At the 60000 plants/ha density, stems of sunflower grown with 1.0 g EDTA Na4·2H2O per kg soil accumulated more Cd, Ni, and Pb than stems of sunflower grown without the EDTA salt. At this density, concentrations of Cd in stems of sunflower without EDTA and with 1.0 g/kg EDTA salt were 0.6 and 4.6 μg/g, respectively; for Ni, they were 1.7 and 17.6 μg/g, respectively; and for Pb, they were 5.2 and 42.8 μg/g, respectively. Removal of the non-essential heavy metals by sunflower was greater at the higher plant density (60000 plants/ha) compared to the lower one (20000 plants/ha).