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.     

利用粘粒矿物修复重金属污染农业土壤研究进展

Heavy metal contamination of agricultural soils poses risks and hazards to humans.The remediation of heavy metal-polluted soils has become a hot topic in environmental science and engineering.In this review,the application of clay minerals for the remediation of heavy metal-polluted agricultural soils is summarized,in terms of their remediation effects and mechanisms,influencing factors,and future focus.Typical clay minerals,natural sepiolite,palygorskite,and bentonite,have been widely utilized for the in-situ immobilization of heavy metals in soils,especially Cd-polluted paddy soils and wastewater-irrigated farmland soils.Clay minerals are able to increase soil pH,decrease the chemical-extractable fractions and bioavailability of heavy metals in soils,and reduce the heavy metal contents in edible parts of plants.The immobilization effects have been confirmed in field-scale demonstrations and pot trials.Clay minerals can improve the environmental quality of soils and alleviate the hazards of heavy metals to plants.As main factors affecting the immobilization effects,the pH and water condition of soils have drawn academic attention.The remediation mechanisms mainly include liming,precipitation,and sorption effects.However,the molecular mechanisms of microscopic immobilization are unclear.Future studies should focus on the long-term stability and improvement of clay minerals in order to obtain a better remediation effect.     

Heavy Metal Accumulation in Plants on Mn Mine Tailings

The Xiangtan Manganese （Mn） Mine in the middle of Hunan Province, China, has been mined since 1913 with mine tailings including excavated wastes, wastewater, and smelting wastes. A survey was conducted on the Mn mine tailing soils and eight plants on the Mn mine tailings. The concentrations of soil Mn, Pb, and Cd and the metal-enrichment traits of these eight plants were analyzed simultaneously. Exceptionally high concentrations of these three metals were found in the soils, especially on the tailing dam. Each plant investigated in this study accumulated the three heavy metals, but no hyperaccumulator of these metals was found. However, analysis indicated that Poa pratensis Linn., Gnaphalium affine D. Don, Pteris vittata L., Conyza canadensis （L.） Cronq., and Phytolacca acinosa Roxb. possessed specially good metalenrichment and metal-tolerant traits. P. pratensis, G. affine, and P. vittata were Pb-tolerant plants; and C. canadensis, P. pratensis, and G. affine were Cd-tolerant plants. P acinosa had a great tolerance to Mn, and it was a valuable plant for on-site phytoremediation. Phragmites communis Trin. was found to have high metal tolerance and economic benefit as a raw material for paper and should be considered for soil remediation. G. affine and C. canadensis had excessive accumulation of Mn and could be useful in phytoremediation. However, although P. pratensis was a good accumulator, it was not a suitable plant for soil remediation because its biomass was too little.     

土壤中氯苯类化合物的归趋过程及潜在修复策略研究进展

Chlorobenzenes (CBs) are a group of organic pollutants that pose a high environmental risk due to their toxicity,persistence and possible transfer in the food chain.Available data in literature show that CBs are detected in different environmental compartments such as soil,water,air and sediment.The widespread presence of CBs in the environment is related to their former extensive use in agriculture and industry.Some CBs are ranked in the list of priority pollutants by the Stockholm Convention,and their reduction or elimination from the environment is therefore of high importance.Environmental risk assessment of CBs requires knowledge on the role and importance of the main environmental fate processes,especially in soil.Furthermore,development of remediation strategies for reduction or elimination of CBs from the environment is related to the enhancement of fate processes that increase their dissipation in various environmental compartments.The main objectives of the current review were to present up-to-date data on fate processes of CBs in the soil environment and to explore possible remediation strategies for soils contaminated with CBs.Dechlorination of highly-chlorinated benzenes is the main degradation pathway under anaerobic conditions,leading to the formation of lower-chlorinated benzenes.Biodegradation of lower-chlorinated benzenes is well documented,especially by strains of adapted or specialized microorganisms.Development of techniques that combine dechlorination of highly-chlorinated benzenes with biodegradation or biomineralization of lower-chlorinated benzenes can result in useful tools for remediation of soils contaminated with CBs.In addition,immobilization of CBs in soil by use of different amendments is a useful method for reducing the environmental risk of CBs.     

伊朗Zanjan城市尾矿土壤中入侵植物的抗氧化能力和金属积累情况

Tailings of a Pb and Zn mine as a metal-contaminated area (Zone 1) with two pioneer plant species, Peganum harmala and Zygophyllum fabago, were investigated and compared with a non-contaminated area (Zone 2) in the vicinity. Total concentrations of Pb, Zn, and Cu in the soil of Zone 1 were 1 416, 2 217, and 426 mg kg-1 , respectively, and all exceeded their ranges in the normal soils. The soil pH was in the neutral range and most of the physical and chemical characteristics of the soils from both zones were almost similar. The species Z. fabago accumulated higher Cu and Zn in its aerial part and roots than the normal plants. On the other hand, their concentrations did not reach the criteria that the species could be considered as a metal hyperaccumulator. The species P. harmala did not absorb metals in its roots; accordingly, the accumulation factor values of these metals were lower than 1. The contents of chlorophyll, biomass, malondialdehyde, and dityrosine in these two species did not vary significantly between the two zones studied. In Zone 1, leaf vacuoles of Z. fabago stored 35.6% and 43.2% of the total leaf Cu and Zn, respectively. However, in this species, the levels of phytochelatins (PCs) and glutathione (GSH) and antioxidant enzyme activities were significantly higher in Zone 1 than in Zone 2. In conclusion, metal exclusion in P. harmala and metal accumulation in Z. fabago were the basic strategies in the two studied pioneer species growing on the metal-contaminated zone. In response to metal stress, elevation in antioxidant enzyme activities, increases in the PCs and GSH levels in the aerial parts, and metal storage within vacuoles counteracted each other in the invasion mechanism of Z. fabago.     

根迹土壤根诱导的化学变化对植物吸收重金属的影响

It is increasingly recognized that metal bioavailability is a better indicator of the potential for phytoremediation than the total metal concentration in soils; therefore, an understanding of the inffuence of phytoremediation plants on metal dynamics at the soil-root interface is increasingly vital for the successful implementation of this remediation technique. In this study, we investigated the heavy metal and soil solution chemical changes at field moisture, after growth of either Indian mustard (Brassica juncea) or sunffower (Helianthus annuus L.), in long-term contaminated soils and the subsequent metal uptake by the selected plants. In addition, the fractions of free metal ions in soil solution were determined using the Donnan membrane technique. After plant growth soil solution pH increased by 0.2-1.4 units and dissolved organic carbon (DOC) increased by 1-99 mg L^-1 in all soils examined. Soluble Cd and Zn decreased after Indian mustard growth in all soils examined, and this was attributed to increases in soil solution pH (by 0.9 units) after plant growth. Concentrations of soluble Cu and Pb decreased in acidic soils but increased in alkaline soils. This discrepancy was likely due to a competitive effect between plant-induced pH and DOC changes on the magnitude of metal solubility. The fractions of free Cd and Zn ranged from 7.2% to 32% and 6.4% to 73%, respectively, and they generally decreased as pH and DOC increased after plant growth. Metal uptake by plants was dependant on the soil solution metal concentration, which was governed by changes in pH and DOC induced by plant exudates, rather than on the total metal concentrations. Although plant uptake also varied with metal and soil types, overall soluble metal concentrations in the rhizosphere were mainly inffuenced by root-induced changes in pH and DOC which subsequently affected the metal uptake by plants.     

Plant- and microbe-assisted biochar amendment technology for petroleum hydrocarbon remediation in saline-sodic soils: A review

Soil degradation through salinization and pollution by toxic compounds such as petroleum hydrocarbons(PHCs) in the coastal wetlands has become a significant threat to ecosystem health, biodiversity, and food security. However, traditional remediation technologies can generate secondary pollutants, incur high operating costs, and consume significant quantities of energy. Bioremediation, using plants, biochar, and microbes, is an innovative and cost-effective option to remediate contaminated soils. Biochar, as a plant/microbe growth enhancer, is a promising green approach for the sustainable phytoremediation of PHCs in salinized soils. This review therefore summarizes the effect of plant-and microbe-assisted biochar amendment technology for the remediation of PHCs and salinization. Plant-microbe interactions mediated rhizodegradation despite increasing hydrocarbon sorption. Overall, microbial respiration is more active in biochar amendments, due to faster biodegradation of PHCs and improved soil properties. The use of biochar, plants, and microbes is recommended,as it offers a practical and sustainable option, both ecologically and economically, for the remediation of PHCs and excess salinity. Further development of new green technologies is to be encouraged.     

Human and ecological risks of metals in soils under different land-use types in an urban environment of Bangladesh

Trace metal contamination in soil is of great concern owing to its long persistence in the environment and toxicity to humans and other organisms.Concentrations of six potentially toxic trace metals,Cr,Ni,Cu,As,Cd,and Pb,in urban soils were measured in Dhaka City,Bangladesh.Soils from different land-use types,namely,agricultural field,park,playground,petrol station,metal workshop,brick field,burning sites,disposal sites of household waste,garment waste,electronic waste,and tannery wast,and construction waste demolishing sites,were investigated.The concentration ranges of Cr,Ni,Cu,As,Pb,and Cd in soils were 2.4–1258,8.3–1044,9.7–823,8.7–277,1.8–80,and 13–842 mg kg^-1,respectively.The concentrations of metals were subsequently used to establish hazard quotients(HQs)for the adult population.The metal HQs decreased in the order of As>Cr>Pb>Cd>Ni>Cu.Ingestion was the most vital exposure pathway of studied metals from soils followed by dermal contact and inhalation.The range of pollution load index(PLI)was 0.96–17,indicating severe contamination of soil by trace metals.Considering the comprehensive potential ecological risk(PER),soils from all land-use types showed considerable to very high ecological risks.The findings of this study revealed that in the urban area studied,soils of some land-use types were severely contaminated with trace metals.Thus,it is suggested that more attention should be paid to the potential health risks to the local inhabitants and ecological risk to the surrounding ecosystems.     

高产生物能植物蓖麻作为铜污染土壤上潜在植物修复剂

Copper (Cu) contamination in the environment has been increased during the years with agricultural and industrial activities.Biotechnological approaches are needed for bioremediation in these areas. The aims of this study were i) to evaluate the phytoremediation capacity of the high-yielding bioenergy plant castor bean (Ricinus communis L.) in vineyard soils (Inceptisol and Mollisol) contaminated with Cu and a Cu mining waste; ii) to characterize the castor bean as a Cu phytoremediation plant; and iii) to evaluate the nutrient uptake by castor bean. Castor bean plants cultivated in soil with toxic levels of Cu for 57 d exhibited high phytomass production, a high tolerance index of roots’ fresh mass and shoots’ dry mass, a high level of Cu phytoaccumulation in the roots and also, a robust capacity for Cu phytostabilization. Furthermore, castor bean plants did not significantly deplete soil nutrients(such as N, P, and Mg) during cultivation. Plants cultivated in Inceptisol, Mollisol and Cu mining waste exhibited a strong potential for Cu phytoaccumulation, with values of 5 900, 3 052 and 2 805 g ha-1, respectively. In addition, the castor bean’s elevated phytomass production and strong growth in Cu-contaminated soils indicated a high level of Cu phytoaccumulation and a potential application in biofuels. These findings indicate that the castor bean is a efcient hyperaccumulator of Cu and a potential candidate plant for the phytoremediation of Cu-contaminated soil.     

丛枝菌根真菌在植物修复砷污染土壤中的作用

丛枝菌根真菌能增强植物对矿质元素的吸收、提高植物的抗逆性、增强抗病性、改善植物根际微环境,减轻重金属对植物的毒害,影响植物对重金属的吸收和转运,在重金属污染土壤的植物修复中显示出极大的应用潜力。近年来,As污染已成为全球非常突出且急需解决的环境问题之一,对As污染土壤的生物修复也因而成为研究热点。本文主要从丛枝菌根真菌改变土壤pH和酶活性、增强植物对As的耐性和影响植物对As的吸收方面综述了丛枝菌根在As污染土壤修复中应用的研究进展,揭示出菌根应用在As污染土壤中的作用潜力和研究方向。     

Fertilizer amendment for improving the phytoextraction of cadmium by a hyperaccumulator <Emphasis Type="Italic">Rorippa globosa</Emphasis> (Turcz.) Thell

Purpose  

Two main pathways of phytoremediation of heavy metal-contaminated soils are phytostabilization and phytoextraction. Some soil amendments can strengthen phytostabilization or phytoextraction through either reducing heavy metal bioavailability in soil or increasing the heavy metal accumulation capacity of the hyperaccumulator (enhancing heavy metal concentration or shoot biomass of the hyperaccumulator). Urea and chicken manure are often used as fertilizers. This research will explore their effects on a newly found hyperaccumulator, Rorippa globosa (Turcz.) Thell., phytoremediating cadmium (Cd).     

重金属污染土壤的螯合剂诱导植物修复研究进展

植物修复作为一种生态友好型原位绿色修复技术成为重金属污染土壤修复研究的热点。然而,目前最具有推广价值的超积累植物因生物量低、生长缓慢、对重金属的积累具有专一性等缺点,大大限制了植物修复技术在重金属污染尤其是复合重金属污染土壤治理方面的推广应用。利用生长速度快、生物量大的普通植物借助其它技术辅助的联合植物修复便成了有效可行的替代途径和研究焦点。近年来,金属螯合剂诱导的化学-植物联合修复技术备受关注。本文综述了螯合剂诱导植物修复技术的研究进展、修复机理和目前存在的问题,并对该项技术的未来研究方向给予了展望。     

蚯蚓在植物修复重金属污染土壤中的应用前景

重金属污染土壤的植物修复技术是绿色生物技术,该技术的应用受制于两个主要因素:超积累植物生物量小和土壤中重金属有效性低。本文在收集大量资料基础上,论述了蚯蚓与重金属的相互关系:重金属对蚯蚓的毒理效应和蚯蚓对重金属的忍耐力。根据在重金属污染土壤中,蚯蚓活动能提高植物生物量和土壤中的重金属的生物有效性,论证了在重金属污染土壤植物修复技术中引入蚯蚓的可行性,并指出引入蚯蚓的植物修复技术当前的研究热点及今后的研究方向。     

内生细菌强化重金属污染土壤植物修复研究进展

近年来,植物修复因其独特的优势备受推崇,尤其是当前植物内生细菌的应用为植物修复重金属污染土壤提供了有效的新方案.在植物修复过程中,耐重金属的内生细菌利用与植物的共生互惠关系,通过自身的抗性系统缓解重金属的毒性,促进植物对其迁移,并通过溶磷、固氮等途径改善植物营养以及分泌植物激素、铁载体、特异性酶、抗生素等作用,促进植物在逆境条件下的生长和对重金属的富集.本文综述了近年来国内外关于重金属抗性植物内生细菌促进植物生长、增强植物对重金属的抗性以及影响重金属在植物体内吸收、转运和积累的作用机制,系统分析了内生细菌促进植物修复重金属污染土壤的机理,并进一步讨论了植物内生细菌在重金属污染土壤植物修复工程中的应用前景与研究方向.     

3种有机酸对伴矿景天修复效率及土壤微生物数量的影响

伴矿景天(Sedumplumbizincicola)是一种Cd和Zn的超积累植物,常用于Cd污染土壤的植物修复。有机酸能够提高土壤重金属的有效性,促进植物对重金属的积累,对重金属污染土壤的植物修复效率具有强化作用,并对土壤微生物数量有重要影响。以河潮土和红黄泥为供试土壤,探讨了乙二胺四乙酸(EDTA)、柠檬酸、草酸对伴矿景天修复效率和土壤微生物数量的影响。结果表明,有机酸能显著提高土壤有效态Cd含量,柠檬酸处理的效果最好,河潮土和红黄泥中有效态Cd含量较单种伴矿景天分别增加72.73%,12.99%(P<0.05);伴矿景天地上部Cd含量在河潮土和红黄泥中以EDTA处理最高,在河潮土和红黄泥中分别比单种伴矿景天增加99.24%和33.32%;与单种伴矿景天相比,添加有机酸处理河潮土和红黄泥中伴矿景天修复效率显著提高。添加有机酸比单种伴矿景天显著增加土壤中微生物数量,其中柠檬酸处理河潮土中细菌和真菌数量分别增加34.38%和68.42%(P<0.05),草酸处理红黄泥中放线菌数量增加150.00%。研究结果可为重金属污染土壤的植物强化修复提供理论支撑。     

香薷属植物在重金属修复中的应用进展

香薷属植物应用于重金属修复经历了矿区植物资源调查和比较、室内模拟研究、田间规模修复以及修复后处置研究,已经初步形成一个植物修复技术的完整体系。在现有技术条件下,把生态修复模式、品种驯化及诱导剂"配方"应用到香薷属植物修复土壤重金属污染对提高修复效率具有重要意义。     

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。     

根际促生菌及其在污染土壤植物修复中的应用

植物对重金属吸收、转运和积累以及植物生物学特征使其成为修复重金属污染土壤的重要手段之一。然而,由于植物对重金属的耐受性有限而限制其广泛实际应用,因而探讨植物修复技术强化措施就显得尤为重要。随着自然资源的开发和技术的发展,微生物调控使植物修复技术变得更为可行和更有价值。回顾近年来新兴的微生物调控技术,植物根际促生菌资源因其对环境无污染,可利用自身的抗性系统减缓重金属对植物的毒性,促进植物的生长和影响重金属的迁移等优势,在修复过程中发挥着重要作用。目前,国内外就植物根际促生菌的筛选、鉴定和应用价值等方面已经做了大量的相关研究。本文综述了根际促生菌-植物相互作用的机制及其促进植物修复重金属污染土壤的作用原理。