有机氯农药六六六污染土壤的植物修复研究

我国20世纪六七十年代大量施用的有机氯农药,由于其性质极其稳定,在土壤至今仍有残留。植物修复有机农药污染土壤并不多见,但具有广阔的应用前景。此项研究对提高土壤环境质量、保证农产品的安全、实现农业可持续发展等有着重要的理论和现实意义。文章以多花黑麦草(Lolium multiforum Lan.)、紫花苜蓿(Medicago sativa L.)和籽粒苋(Amaranthus hypochondriacus L.)作为供试植物,在有机氯农药六六六(HCH)质量分数为1.09 mg.kg-1的污染土壤中种植3个月,研究了种植不同植物条件下土壤中HCH的消解情况。研究结果表明,与对照相比,种植植物大大提高了土壤中微生物数量和酶的活性,并且微生物的数量和酶的活性与土壤中HCH的消解密切相关。试验结束后,不同处理中HCH及其4种异构体的总含量降低幅度为43.87%~65.79%,其中种植紫花苜蓿和多花黑麦草的处理中HCH消解较快,对HCH污染土壤修复的效果较好。可见,植物修复技术是一种可行的环境友好的修复六六六污染土壤的技术。     

土壤石油污染物生物通风修复的研究进展

生物通风是一种去污效果好、操作费用低的土壤原位修复技术。文章概述了生物通风系统的结构、设计目的、适用范围和优缺点，详细论述了生物通风的国内外研究现状，包括现场应用、影响因素和强化技术及理论研究，并展望了生物通风在我国的应用前景。     

基因工程改良植物对重金属污染土壤的修复

利用基因工程改良植物，调整植物吸收、运输和富集重金属的能力以及它们对重金属的耐受性，开拓了植物修复的新领域。到目前为止，已有成功改变这些特性的少数例子。例如，汞离子还原酶可以改善植物抵抗力和提取能力，金属巯基蛋白可增强植物对镉的耐受力，铁还原酶和铁蛋白可增加植物对铁的吸收量。文章综述和讨论了这方面的研究进展及方向。     

紫花苜蓿对铅污染土壤修复能力及其机理的研究

以10 mmol/L Pb(NO3)2处理紫花苜蓿幼苗10 d,分析了Pb在紫花苜蓿幼苗根、茎、叶中的积累情况,Pb在根表皮细胞中的亚细胞区域化特点,以及Pb在紫花苜蓿体内的主要存在形式。结果表明,Pb在紫花苜蓿幼苗中积累量(M)特点为:M根 >M茎 >M叶。同时X-ray微区分析显示,胞间隙是紫花苜蓿积累Pb浓度最高的部位,细胞壁和液泡次之,胞质中最低。Pb的存在形式分析表明Pb在紫花苜蓿体内主要以难溶的形式存在,另外BSO能够加剧Pb污染对紫花苜蓿幼苗Pn和生长的抑制作用,显示了紫花苜蓿对Pb的耐受与植物络和素的形成有关。这些都表明紫花苜蓿对Pb具有一定的耐受机制,避免其对胞质代谢的毒性。同时紫花苜蓿具有很高的生物量和对Pb较高的富集作用,因此是一种很有利用价值的土壤铅污染修复植物。     

Combined bioremediation for lead in mine tailings by Solanum nigrum L. and indigenous fungi

Lead-contaminated mine tailings were bioremediated using microbial/phyto remediation. The optimum lead accumulation and tolerance capacity of the plant–microbe partnership were investigated, and their mechanisms were evaluated further under varied levels of lead contamination through a flowerpot experiment in a greenhouse. Enzymes activities revealed that bioremediation has improved fertility and metabolism of tailing soil. The removal efficiency of lead was in the order of microbial/phytoremediation?>?phytoremediation. Solanum nigrum L. was not shown to be a hyperaccumulator for lead. Mucor circinelloides significantly enhanced the growth response and lead accumulation in plants more than Mortierella and Trichoderma asperellum. Moreover, Mortierella was discovered to have good metal tolerance capacity under high Pb concentrations (1200 and 1600?mg?kg^?1). The results for lead bioavailability showed that phytostabilisation serves as a major repair pathway for S. nigrum L. Effective fractions were immobilised for decreased bioavailability by T. asperellum and M. circinelloides. On the contrary, an increased amount of lead was mobilised for increased bioavailability by Mortierella. This study provides new insights into the feasibility of using S. nigrum L. and the aforementioned indigenous fungus strains for large-scale bioremediation of mine tailings.     

玉米和黄豆对酸性土壤中石油的去除效果

通过室外盆栽试验,比较了玉米(Zea mays)和黄豆(Glycine max)2种植物对酸性土壤中石油污染物的去除效果。结果表明,2种植物对土壤中石油具有良好的耐受性和去除效果。玉米和黄豆对石油烃的去除率分别可达38.41%～64.30%和34.24%～63.96%,而自然条件下石油去除率仅为23.77%～58.43%。聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)图谱分析结果显示,当w(石油)为0～17 295 mg.kg-1时,土壤微生物群落的丰度和多样性大致随着w(石油)的升高而呈下降趋势,植物根系能够选择性地促进根际微生物的增殖,且玉米根系的作用比黄豆明显。     

水生维管束植物在水污染中的应用

随着水污染的加剧，高效低耗的水污染处理技术逐渐受到人们的重视，水生维管束植物以其特有的组织和生态功能及易于人工操纵等原因而在净化水体污染、防治富营养化方面发挥了重要的作用。文章对水生维管束植物在水质净化中的作用、影响因素、水生植物的综合利用及其在水污染监测中的作用等方面进行了系统分析，提出多种植物组合比单种植物能更好地实现对水体的净化，通过温度、水深的调控措施可以加强水生维管束植物对水质的净化效果，温度、水深、水质状况以及水生植物的经济价值等是水生植物选择的重要因素。指出了当前水生维管束植物研究中存在的一些问题，认为在人为操纵下，对于水生植物的长效管理是其在水污染应用中的一个重要内容。     

外生菌根真菌接种和施磷对油松苗抗盐性的影响

采用3种不同的外生菌根真菌Boletus edulis、Xerocomus chrysenteron和Gomphidius viscidus，在山东东营盐渍土环境胁迫下，研究外生菌根真菌接种和施磷对油松(Pinus tabulaeformis)生长的影响及其可能机理。结果表明，接种和施磷都增加了油松植株的干质量，但施磷不如接种对植物生长的促进作用明显；接种外生菌根后，油松体内的K元素含量显著增加，而Na元素的含量没有明显变化，使得w(K)／w(Na)增加，从而改变了植株体内的离子平衡，减轻离子的毒害作用。而不是通过直接减少植物对Na的吸收来增加植物的抗盐性；同时，接种后外生菌根增加了油松对P的吸收，改善了盐渍土壤导致的植物营养亏缺，促进了植物在盐渍环境下的生长。     

Isolation and identification of fungi tolerant to polycyclic aromatic hydrocarbons and coal tar from different habitats in Lithuania

A group of 36 fungal strains, belonging to the Lithuanian mycobiota, was collected and isolated from different locations, habitats, and matrices, including creosote-treated wood in storage yards for crosstie wastes. The eight most perspective strains selected according to preliminary assessment of tolerance to coal tar were subsequently identified combining taxonomical evaluation and molecular techniques. The tolerance of the eight identified fungal species (five basidiomycetes and three ascomycetes) to the presence of various concentrations of coal tar, and for the four most perspective fungal strains (Pleurotus sp., Schizophyllum sp., Irpex lacteus, Bjerkandera adusta) to polycyclic aromatic hydrocarbons was evaluated. The ligninolytic enzymatic activity assay of the isolated strains resulted in a good correspondence between the tolerance to pollutants and the capability to produce ligninolytic enzymes indicating that this group of white-rot fungi is perspective for further investigation and eventual usage for mycoremediation of polycyclic aromatic hydrocarbons polluted substrates.     

蚯蚓在植物修复铜、镉污染土壤中的作用

以红壤和高砂土为供试土壤,分别加入3个浓度的重金属铜离子Cu2 (100,200,400 mg kg-1)或镉离子Cd2 (5,10,20 mg kg-1),每钵接种6条蚯蚓(Pheretimasp.),种植黑麦草(Lolium multiflorum),以不加蚯蚓为对照(CK),研究蚯蚓活动对Cu、Cd污染土壤中黑麦草生长及铜、镉生物有效性的影响.结果表明,添加蚯蚓显著提高了Cu2 、Cd2 污染的高砂土中黑麦草地上部分的生物量,增幅为33%~96%;仅增加了Cu2 污染浓度低于200 mg kg-1的红壤中黑麦草地上部分的生物量;添加蚯蚓显著增加了两种土壤中速效N的含量,促进了黑麦草地上部分对N的吸收,对速效P、K的含量以及黑麦草中P、K含量无显著影响;添加蚯蚓显著提高了红壤中铜(Cu)、镉(Cd)DTPA提取态的含量,对高砂土中DTPA提取态Cu、Cd的含量无显著影响;增加了高砂土中和添加Cu污染浓度低于200 mg kg-1的红壤中黑麦草地上部分吸收Cu的总量,而对黑麦草吸收Cd的量无显著影响.加入蚯蚓可以不同程度地改善植物修复技术应用中受制的两个主要因素.表4参30     

缓释微胶囊EDTA强化玉米提取土壤中铅铜的效应研究

将EDTA转化成具有缓释性能的微胶囊EDTA（Cap-EDTA）作为螯合剂,采用大宝山矿区周边重金属复合污染农田土壤进行重金属连续批浸提及盆栽试验,比较研究Cap-EDTA和未微胶囊化EDTA（Ncap-EDTA）对土壤铅铜活化的动态变化及其对玉米吸收提取铅铜的影响。结果表明：Cap-EDTA处理土壤溶液中初始增溶的铅铜质量分数显著低于Ncap-EDTA处理,且使土壤溶液中的铅铜质量分数长时间持续保持在适度范围内。添加Cap-EDTA的处理显著提高玉米吸收提取铅铜的效率,如实施3 mmol·kg-1的Cap-EDTA使玉米地上部Pb的积累高达1.26 mg·pot-1,是对照处理的1.9倍,是等量Ncap-EDTA处理的1.4倍。因此,在进行污染土壤植物修复的EDTA调控时,采用微胶囊化EDTA,能降低因直接实施EDTA而带来的污染地下水风险,且显著提高玉米修复效率。     

Heavy metals in soils and crops in Southeast Asia

In a reconnaissance soil geochemical and plant survey undertaken to study the heavy metal uptake by major food crops in Malaysia, 241 soils were analysed for cation exchange capacity (CEC), organic carbon (C), pH, electrical conductivity (EC) and available phosphorus (P) using appropriate procedures. These soils were also analysed for arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb) and zinc (Zn) using aqua regia digestion, together with 180 plant samples using nitric acid digestion. Regression analysis between the edible plant part and aqua regia soluble soil As, Cd, Cr, Cu, Hg, Ni, Pb and Zn concentrations sampled throughout Peninsular Malaysia, indicated a positive relationship for Pb in all the plants sampled in the survey (R ² = 0.195, p < 0.001), for Ni in corn (R ² = 0.649, p < 0.005), for Cu in chilli (R ² = 0.344, p < 0.010) and for Zn in chilli (R ² = 0.501, p < 0.001). Principal component analysis of the soil data suggested that concentrations of Co, Ni, Pb and Zn were strongly correlated with concentrations of Al and Fe, which is suggestive of evidence of background variations due to changes in soil mineralogy. Thus the evidence for widespread contamination of soils by these elements through agricultural activities is not strong. Chromium was correlated with soil pH and EC, Na, S, and Ca while Hg was not correlated with any of these components, suggesting diffuse pollution by aerial deposition. However As, Cd, Cu were strongly associated with organic matter and available and aqua regia soluble soil P, which we attribute to inputs in agricultural fertilisers and soil organic amendments (e.g. manures, composts).     

Study of metal accumulation in wild plants using principal component analysis and ionic impulsions

The objective of this work is to apply principal component analysis (PCA) and ionic impulsions to the study of the accumulation and uptake of metals in wild plants. Soil samples were taken in three locations and the following plant species were selected: Poa, Pteridium aquilinum, Diplotaxis, Plantago lanceolata and Trifolium repens. After determining contents of Na, K, Ca, Mg, Mn, Pb, Co, Ni, Cu, Cr, Zn, Cd and Fe in the plant samples and in the soils, principal component analysis was carried out for plant data treatment. Sample position maps revealed that there was no substantial differences among samples when plant species or sampling locations were used as a criteria. As the factors obtained by PCA only correlated with one or two variables, the study of accumulation patterns of metals was carried out by using ionic impulsions. The presence of large amounts of pollutants (like Cd, Cr) in plants is related to a greater assimilation of essential micronutrients in order to counteract the influence of the pollutants.     

Lead content of plants and soils from three abandoned smelter areas in and near Socorro,New Mexico

Two primary lead smelters and one secondary lead smelter have been active in the Socorro, New Mexico (USA) area in the last 110 years: the Billing smelter from 1883 to 1894, the Cuba Road smelter from 1881 to 1900, and Cal West from 1979 to 1984. Samples of plants and surface soil under each plant from all three sites were analysed for lead. The plants consisted of sparse grasses, cacti, creosote bush, snakeweed, mesquite and fourwing saltbush. Lead levels in the plants increased (2-440 g g^–1) as the lead in the alkaline soils (25-10000 ng g^–1) increased. However, the BAC (biological absorption coefficient), which is the ratio of lead content in the plant to the lead content in the soil, a measure of relative accumulation, decreased by one to two orders of magnitude, except for grasses and snakeweed. At background lead levels, there was little difference between lead in rootsversus foliage. At high lead levels, there was higher lead in roots versus foliage at the Billing and Cuba Road sites. The reverse was noted at Cal West. Because this is a recent operation, the higher lead in foliage may be due to foliar uptake. Plant growth at all sites appeared healthy.     

植物与微生物对石油污染土壤修复的影响

为了研究生物对石油污染土壤的修复效果,在从石油污染土壤中筛选石油降解微生物的基础上,采用盆栽试验,进一步研究了4种植物和筛选到的微生物对石油污染土壤修复的影响.选择中原油田地区的原油和潮土,采取人工污染方法,设计石油污染水平为15 g·kg-1.试验设置3类处理,即单独添加微生物、单独种植植物(分别为向日葵、狗牙根、棉花、高丹草)、微生物分别与4种植物(向日葵、狗牙根、棉花、高丹草)组合.结果表明:在石油污染土壤中单独添加石油降解微生物,120 d时,石油降解率达到67.0%;向日葵、狗牙根、棉花、高丹草对土壤中石油降解也具有一定效果,120 d时,石油降解率分别达到38.23%、36.57%、40.67%、38.67%;添加微生物和种植植物联合对石油降解能力大小顺序为棉花+微生物＞向日葵+微生物＞狗牙根+微生物＞高丹草+微生物.其中,棉花与微生物联合修复120 d可以使污染土壤石油降解率达到85.67%,在各种处理中对污染土壤中石油的降解效果最好.     

植物吸收修复对土壤镍及其主要化学性质的影响

采用室内盆栽试验方法,研究了外源镍污染土壤的植物吸收修复对土壤镍形态和土壤主要化学性质的影响。试验用水稻土添加NiSO4·6H2O(100～1600mgkg-1)经过12周的驯化培养后,种植了镍超累积植物Alyssu mmurale,110 d后收获植物并进行了试验土壤镍的形态和主要化学性质的分析,采用再分配系数和结合强度系数对植物修复效果进行了定量分析。结果表明,根区土壤中DTPA提取态镍的数量明显减少,根区土壤DTPA-Ni与非根区土壤DTPA-Ni之比的范围在0.33～0.61之间。每盆植物提取镍量为6.61～31.18mg,植物提取量随着添加镍量增加而增加,地上部分最大镍含量达到12454.1mgkg-1。根区的再分配系数在2.17～4.19之间,而非根区的再分配系数在6.87～15.91之间,再分配系数随着镍添加量的增加而增大;根区的结合强度系数为0.84～0.39,而非根区的则为0.88～0.26,随着土壤中镍添加量的增加,结合强度系数逐渐减小。植物吸收修复后,根区土壤镍的再分配系数降低、结合强度系数增大,表明土壤镍各形态之间的稳定性增加,因此植物修复可以加快外源镍在土壤中的稳定。试验结果也表明,根区土壤中pH随着镍添加量的增加呈下降趋势、但较非根区土壤的高;根区土壤有机碳亦较非根区的高。     

植物修复土壤重金属污染中外源物质的影响机制和应用研究进展

重金属进入土壤后难以被降解,并通过食物链在生物体内富集,长此以往会导致中毒、癌症、畸形、突变,严重影响了人类生产活动及地球生态系统的稳定。植物修复技术是一种经济有效的重金属污染修复技术,其依靠超富集植物强大的自身抗性机制,从土壤中提取或稳定重金属,达到污染治理的目的。然而修复土壤重金属污染的超富集植物通常生长缓慢、生物量低,其抗性机制也会受到植物本身对重金属胁迫的阈值限制,当胁迫超过这个阈值,植物修复的效率就会大大降低甚至失去修复功能。文章在解析植物重金属相互作用机制的基础上,综述了添加外源物质对重金属毒害植物的缓解效应以及其在强化植物修复土壤重金属污染中的应用研究进展;介绍了应用外源物质调控植物吸收转运重金属的3种途径,分别为提高土壤重金属生物利用度、促进植物生长以及增强植物耐性。提出了应用外源物质作为强化植物修复措施的潜力及今后的研究方向,其未来的研究应着重于以下方面:明确外源物质的应用浓度、时期、方式与植物吸收转运重金属之间的关系;从植物内源激素及信号分子间的互作、抗逆基因表达、内生及根际微生物等不同层面上揭示外源物质对植物积累重金属的调控机理;开展外源物质与其他植物修复强化技术的联合应用研究。这些研究可为土壤重金属污染的植物修复技术及其强化措施研究提供科学依据,同时也对植物修复工程技术的发展实践具有一定的指导意义。     

土壤重金属污染的植物修复中转基因技术的应用

重金属污染的植物修复技术以其费用低廉、不污染环境等优点一度成为环境科学界研究的热点。为了克服植物修复技术中超积累植物生长缓慢和地上部生物量小等带来的限制，近年来研究者通过大量试验研究发展，外源基因在植物体内的高效表达可以提高植物吸收、运输、降解污染物的能力和修复的效率。本文首先对目前国内外重金属污染土壤植物修复的研究动态进行综述，重点论述了PCs、MTs、MerA、MerB、ArsC、γ-ECS等转基因在土壤重金属污染植物修复中的应用，最后指出在充分考虑到转基因植物给生态环境带来潜在威胁的前提下，转基因技术的研究与开发不仅可以促进多学科的交叉研究和丰富环境科学的研究领域，更重要的是在很大程度上有效地克服了目前土壤重金属污染植物修复中存在并急需解决的棘手问题，为土壤重金属污染的植物修复提供了更加广阔的应用和发展前景。