沉水植物对重金属的吸收净化和受害机理研究进展

沉水植物对重金属的积累净化和受害机理研究主要集中在4个方面: (1)沉水植物对重金属(包括放射性物质)的吸收、积累和净化作用; (2)沉水植物对重金属的抗性强弱和机制; (3)沉水植物用于监测水体的重金属污染; (4)沉水植物的重金属胁迫机制, 包括重金属对植物形态和显微结构的损伤, 对植物抗氧化酶系统的影响, 对植物的叶绿素、蛋白质以及光合与呼吸作用等生理生化指标的影响, 植物对重金属的吸附和转运动力学, 以及Zn对Cd毒害的拮抗等。     

凤眼莲等水生植物对重金属污水监测和净化作用的研究

本文研究了凤眼莲、芦苇、蒲草、杏菜、黑藻等高等水生植物对含砷、汞、镉污水的监测作用和净化能力以及温度、pH值等因子对植物的影响。初步认为凤眼莲是含砷污水的监测植物,同时又是含砷、汞,镉污水的净化植物。芦苇,蒲草是抗污能力较强的植物,并能吸收积累污水中的砷、汞、镉。水生植物对砷、汞、镉的忍耐力大小是因其植物生活型不同而异,一般为挺水植物>飘浮、浮叶植物>沉水植物。积累量为沉水植物>飘浮、浮叶植物>挺水植物。植物对重金属元素的吸收积累受温度和pH值等生态因子的制约。     

沉水植物生长和腐解对富营养化水体氮磷的影响机制研究进展

沉水植物作为湖泊、河流等生态系统的主要高等植物, 在修复富营养化水体中的作用日益受到重视, 合理利用沉水植物是去除富营养化水体氮磷的有效途径。沉水植物对水体氮磷的迁移转化影响包括生长和腐解两个阶段。文章综述了沉水植物生长对富营养化水体氮、磷的净化效果和净化机制, 分析了沉水植物腐解对氮、磷迁移转化的持续影响, 并提出了今后沉水植物净化氮、磷的研究方向, 为沉水植物推广应用于修复富营养化水体提供理论基础。     

植物对铅胁迫的耐性及其解毒机制研究进展

植物对重金属元素的耐性、积累特性是利用植物修复铅污染土壤的前提,因而需要全面理解植物对铅吸收、转运、积累和解毒的一系列生理机制.本文从植物自身对铅的适应和防御机制出发,综述了细胞壁和液泡在植物细胞钝化与铅积累中的功能;根系分泌物对铅生物有效性的影响;超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）、谷光苷肽还原酶（GR）、抗坏血酸过氧化物酶（APX）和植物螯合肽、谷胱甘肽在铅解毒中的作用,以及金属硫蛋白和铅特异基因表达的研究进展.并对未来该领域的研究以及铅污染环境植物修复技术的发展进行了展望.     

超积累植物与丛枝菌根真菌共生及其联合吸收积累重金属的效应

利用超积累植物进行重金属污染土壤修复是应对全球大面积分布无机污染问题的重要解决方法之一。超积累植物虽然具有超量积累重金属的能力,但其定植、生长和提取功能的发挥都受到重金属胁迫的显著影响。利用丛枝菌根真菌 (Arbuscular mycorrhizal fungi,AMF) 强化超积累植物功能可联合发挥二者的功能优势,提升修复效率、缩短修复周期、保持修复效果的稳定性和长期性,在日益复杂、严峻的重金属污染治理领域具有重要的研究价值和广阔的应用前景。文中首先给出了超积累植物的概念、中国本土首次报道的典型重金属元素超积累植物和能与AMF形成共生体系的超积累植物名录,系统深入地探讨了AMF对超积累植物生长和吸收累积重金属的影响,以及超积累植物+AMF联合吸收积累重金属的效应与作用机制,认为AMF可通过调节根围理化与生物条件、元素平衡状况、生理代谢和基因表达等途径,增强超积累植物吸收积累重金属的效应,超积累植物+AMF构建的共生体系具备联合修复重金属污染生境的潜力。最后指出了超积累植物+AMF共生联合修复技术当前面临的关键问题、发展方向和应用前景。     

沉水植物茎叶微界面特性研究进展

沉水植物茎叶-水界面是浅水湖泊的重要界面之一,对湖泊生物地球化学循环和水环境质量具有重要影响。富营养化水体中,大量的附着物常富集在沉水植物茎叶表面,形成了特殊的生物-水微界面。对该微界面特性进行深入研究,有助于揭示沉水植物在微环境层面对富营养化水体中物质循环的调控过程和机制。沉水植物茎叶微界面具有促进水体养分转化、改变环境因子及可溶性物质的空间分布,增加物质运输的阻力和距离、降低植物光合作用、调控重金属等生态功能;微界面结构及环境因子受水体营养盐浓度、沉水植物种类及生长阶段等因素的影响。对微界面结构功能的主要研究方法进行了分析总结,并对沉水植物茎叶微界面的研究前沿进行了展望。     

我国土壤重金属污染植物吸取修复研究进展

我国从上世纪90年代中后期开始土壤重金属（含类金属砷）污染的植物吸取修复研究及技术探索,先后发现了一批具有较高研究价值和应用前景的铜、砷、镉、锰等重金属的积累或超积累植物,并从重金属耐性和超积累生理机制、植物吸取修复的根际过程与机制、吸取修复强化措施和修复植物处置与资源化利用等方面进行了研究,同时开展了植物吸取修复技术的示范与应用,已有一些较成功的植物修复工程应用案例,使我国重金属污染土壤植物修复技术,尤其是植物吸取修复技术在国际上产生了较强的影响力。本文就近年来我国土壤重金属污染植物吸取修复研究进展进行了综述,并对今后的发展趋势进行了展望。     

凤眼莲入侵程度对金鱼藻和黑藻生长及种间关系的影响

湿地生态系统中凤眼莲（Eichhornia crassipes）入侵造成湿地植物群落结构退化及功能崩溃,直接影响沉水植物的生长繁殖及初级生产力。目前关于凤眼莲的入侵机制有一定的研究,而关于凤眼莲入侵程度对沉水植物金鱼藻（Ceratophyllum demersum）和黑藻（Hydrilla verticillate）生长及种间关系的影响相对缺乏。以外来入侵植物凤眼莲,沉水植物金鱼藻和黑藻为研究对象,设计凤眼莲入侵程度（无入侵,轻度入侵对应盖度25%,重度入侵对应盖度75%）交叉定植方式（黑藻单种模式、金鱼藻单种模式,金鱼藻和黑藻混种模式）的控制实验,探究凤眼莲入侵强度对沉水植物金鱼藻和黑藻生长及种间关系的影响。结果表明,凤眼莲入侵程度显著降低了金鱼藻的生物量、分枝数;黑藻的株高、分枝数和分节数。无凤眼莲入侵时,两种沉水植物生物量均最大,两者种间竞争关系较强;随凤眼莲入侵盖度增加,两种沉水植物的生物量先急剧降低后略微增加,种间关系经过微弱促进后又变为竞争作用,其中黑藻表现出明显的竞争优势。此外,凤眼莲入侵略微降低了水体中的总氮、总磷含量。结构方程模型分析结果表明凤眼莲入侵以及水体总氮、总磷等水体理化性质对沉水植物生长均有显著负向影响（P<0.05）,且水体理化性质对沉水植物生长的影响强于凤眼莲入侵。总之,凤眼莲入侵显著降低了金鱼藻和黑藻生长繁殖,随着凤眼莲入侵程度增加,两种沉水植物种间关系由竞争转变为促进再转变为竞争。研究结果为凤眼莲入侵有效控制及湿地沉水植被的恢复与重建提供了一定的理论依据和技术支撑。     

重金属污染的植物修复及相关分子机制

随着近代工业的发展,土壤重金属污染问题日益严重。重金属即使在极低浓度下仍然可以对人畜造成健康上的威胁,因此迫切需要有效的修复方法对土壤进行修复。生物修复,特别是植物修复目前已经成为重金属污染修复的重要手段之一,了解相关植物的重金属解毒和积累分子机制是提高修复效率、解决重金属污染问题的基础。文中以土壤修复方式为起点,结合植物吸收积累重金属以及解毒的相关分子机制研究,探讨了植物修复的发展现状以及趋势。     

植物内生细菌修复重金属污染土壤作用机制研究进展

内生细菌生活在植物组织内部,长期以来与宿主植物形成了紧密的共生关系。内生细菌在重金属吸收、耐受和解毒方面具有优良的特性,为修复重金属污染土壤提供了有效的新方案。综述了内生细菌强化植物修复重金属污染土壤的作用机制,包括内生细菌通过产生植物生长调节激素,分泌ACC脱氨酶和几丁质酶等,促进宿主植物在重金属胁迫条件下的生长;通过改变重金属的生物有效性/毒性,减轻植物重金属毒害;通过与植物形成联合修复体,加强植物抗重金属毒性的能力。分析了近几年超富集植物内生细菌多样性及其影响因素,探讨了联合修复过程中影响内生细菌强化修复效果的主要因素,包括内生细菌的来源、活性和环境胁迫等各种生物因素和非生物因素,并对内生细菌与植物联合修复的研究方向进行展望,涉及内生细菌自身存活原因和如何耐受重金属的机制研究,植物内生细菌的行为动力学和代谢,以及内生细菌、植物及土壤之间的生态互作效应等,以期推动内生细菌大规模应用于植物修复重金属污染土壤。     

Heavy metals contamination and accumulation in submerged macrophytes in an urban river in China

Deteriorating urban water quality has attracted considerable attention in China. We investigated the contamination levels and distribution of heavy metals (As, Cd, Cu, Ni, Pb, and Zn) in Yuxi River water and sediments, and assessed the heavy metal accumulation capability of five species of submerged macrophytes: Vallisneria natans (Lour.) Hara, Potamogeton pectinatus L., Hydrilla verticillata (L. f.) Royle, Myriophyllum spicatum L., and Potamogeton crispus L. Samples were collected from upstream and downstream locations in different season. The results showed that the levels of heavy metals in the downstream areas were higher than in the upstream areas. Heavy metal concentrations in the river water during the dry seasons were higher than those during the rainy seasons, and the opposite results appeared in sediments and submerged macrophytes. In general, the river was slightly contaminated by heavy metals, and the concentrations of Pb and Ni in this river should serve as a warning, while Cd and Zn pollution in the sediments desperately needs to be removed. Furthermore, Potamogeton pectinatus L. showed a higher accumulation capacity for these metals among the five native submerged macrophytes and could be defined as a hyperaccumulator for Cd. Therefore, the potential use of native aquatic plants in contaminated rivers is worth further exploration.     

Heavy metals in aquatic macrophytes drifting in a large river

Macrophytes drifting throughout the water column in the Detroit River were collected monthly from May to October 1985 to estimate the quantities of heavy metals being transported to Lake Erie by the plants. Most macrophytes (80–92% by weight) drifted at the water surface. Live submersed macrophytes made up the bulk of each sample. The most widely distributed submersed macrophyte in the river, American wildcelery (Vallisneria americana), occurred most frequently in the drift. A total of 151 tonnes (ash-free dry weight) of macrophytes drifted out of the Detroit River from May to October. The drift was greatest (37 tonnes) in May. Concentrations of heavy metals were significantly higher in macrophytes drifting in the river than in those growing elsewhere in unpolluted waters. Annually, a maximum of 2 796 kg (eight heavy metals combined) were transported into Lake Erie by drifting macrophytes. The enrichment of all metals was remarkably high (range: 4 000 × to 161 000 × ) in macrophytes, relative to their concentration in water of the Detroit River. Detroit River macrophytes are thus a source of contaminated food for animals in the river and in Lake Erie.Contribution 734 of the National Fisheries Research Center-Great Lakes, U.S. Fish and Wildlife Service, 1451 Green Road, Ann Arbor, MI 48105.     

镉、铜和锌胁迫下黑藻活性氧的产生及抗氧化酶活性的变化研究

研究了不同Cd、Cu、Zn处理浓度对黑藻体内活性氧()产生及对抗氧化酶(SOD、POD、CAT)活性的分子毒理学效应以探讨高等水生植物抗氧化酶对重金属胁迫的反应。结果表明,三种重金属都不同程度地加快了产生速率;Cu使SOD、POD、CAT活性下降;Cd也都减弱了SOD和POD活性,而CAT活性在0.5—5mg/L处理浓度时增加;Zn对SOD活性也为抑制作用,当浓度为0.5—5mg/L时POD和CAT活性都上升。关联度分析发现Cd、Cu和Zn胁迫下黑藻起主要保护作用的分别为SOD、POD和CAT,而SOD最易受到影响。Cd、Cu处理下的叶绿素含量也都呈下降趋势,而0.5—5mg/L的Zn浓度刺激了叶绿素合成。所有Zn处理、0.5mg/L的Cu处理和0.5—1mg/L的Cd处理的叶绿素a/b值都大于对照值。除了Cu使可溶性蛋白含量减少外,0.5—5mg/L的Zn和0.5—1mg/L的Cd都使其含量增加。综合起来,Cu的毒性最强,其次为Cd,Zn最弱。致死阈浓度分别为:Cu:0.5—1mg/L;Cd:1—2mg/L;Zn:5—6mg/L。SOD是评价重金属对沉水植物毒性效应的灵敏指标。黑藻对水环境Cu污染反应敏感。       

Concurrent removal and accumulation of heavy metals by the three aquatic macrophytes

Under the present investigation effectiveness of three aquatic macrophytes Pistia stratiotes L. (water lettuce), Spirodela polyrrhiza W. Koch (duckweed) and Eichhornia crassipes were tested for the removal of five heavy metals (Fe, Zn, Cu, Cr and Cd). These plants were grown at three different concentrations (1.0, 2.0 and 5.0mgl(-1)) of metals in laboratory experiment. Result revealed high removal (>90%) of different metals during 15 days experiment. Highest removal was observed on 12th day of experiment, thereafter it decreased. Results revealed E. crassipes as the most efficient for the removal of selected heavy metals followed by P. stratiotes and S. polyrrhiza. Results from analysis confirmed the accumulation of different metals within the plant and a corresponding decrease of metals in the water. Significant correlations between metal concentration in final water and macrophytes were obtained. Plants have accumulated heavy metals in its body without the production of any toxicity or reduction in growth. Selected plants shown a wide range of tolerance to all of the selected metals and therefore can be used for large scale removal of heavy metals from waste water.     

Phytoremediation of Water Using Phragmites karka and Veteveria nigritana in Constructed Wetland

Constructed wetland is an innovative and emerging ecological technology for wastewater treatment. This study was conducted to investigate the effectiveness of a Vegetated Submerged Bed Constructed Wetland (VSBCW) for removal of heavy metals from industrial wastewater in a steel manufacturing company. A pilot Effluent Treatment Plant (ETP) consisting of equalization basin, two VSBCW basins and a storage tank was constructed. The VSBCW was constructed using 10–30 mm round granite for the different zones. This was overlaid by 200 mm deep granite and 150 mm washed sand with Phragmites karka, Vetiveria nigritana and Cana lilies as macrophytes. Irrigation of macrophytes using effluent from the industry was done after 3 months of planting and ETP monitored. Industrial wastewater samples were collected and analyzed for heavy metals such as zinc (Zn), lead (Pb), iron (Fe), manganese (Mn), magnesium (Mg) and chromium (Cr) to know the treatment efficiency of the ETP. Results indicated that the removal efficiencies of the VSBCW for Pb, Mg and Cr were 15.4%, 79.7% and 97.9% respectively. Fe and Mn were seen to increase by 1.8% and 33% respectively. The ETP using locally available macrophytes is effective in the phytoremediation of heavy metals, particularly Cr from the wastewater.     

湖泊水动力变化对沉水植物的影响研究综述

随着全球气候变化加剧及水利工程的快速发展,湖泊水动力状况发生了显著变化。通过影响湖泊水体和沉积物理化性质,水动力变化可以作用于沉水植物生存、生长与分布等方面。在长期适应进化过程中,沉水植物演化出了一系列有效的适应策略,能一定程度上克服水动力变化的负面影响。但当前湖泊水动力变化程度远超沉水植物适应上限,湖泊沉水植物消退已成为全球普遍现象。了解沉水植物适应水动力条件的过程有助于揭示湖泊沉水植被退化机制,为未来沉水植物的保护和恢复提供借鉴。因此,本文系统综述当前湖泊水动力变化成因,水动力变化对沉水植物的不利影响及沉水植物适应策略,包括：繁殖对策、形态学对策、生理对策等。同时,综述当前研究进展,今后还需大力加强沉水植物解剖学及物种忍耐力差异方面的研究。     

Effects of phytoplankton on the distribution of submerged macrophytes in a small canal

Submerged macrophytes have been disappearing from the Kanto Plain, Japan since the 1960s. This disappearance is usually attributable to the interaction between macrophytes and phytoplankton. Phytoplankton contributes to shading of the available light and changes the availability of inorganic carbon from free CO₂ to HCO ₃ ^? for use in photosynthesis. However, limited information is available about the interaction between carbon fraction and submerged macrophytes through phytoplankton abundance. In this short note, we observe the distribution of submerged macrophytes and phytoplankton in a small canal. We found that, despite high photosynthetically active radiation (PAR) in the downstream region, low free CO₂ concentration through phytoplankton abundance can deplete free CO₂ for submerged macrophytes. In contrast, the upstream region exhibited macrophytes in an environment with high free CO₂ concentration. The stable carbon isotope ratio of submerged macrophytes follows this pattern, with more positive values occurring in the downstream region and more negative values in the upstream region. It has been reported that phytoplankton limits light availability for submerged macrophytes, but carbon availability could also be a factor in the distribution of submerged macrophytes. Because the source of water for submerged macrophytes is groundwater, its preservation possibly plays a key role for the restoration of submerged macrophytes.     

Toxicity, accumulation, and removal of heavy metals by three aquatic macrophytes

A comprehensive understanding of the uptake, tolerance, and transport of heavy metals by plants will be essential for the development of phytoremediation technologies. In the present paper, we investigated accumulation, tissue and intracellular localization, and toxic effects of cadmium (Cd), lead (Pb), zinc (Zn), and copper (Cu) in three aquatic macrophytes (the angiosperms Lemna minor and Elodea canadensis, and the moss Leptodictyum riparium). We also tested and compared their capacity to absorb heavy metal from water under laboratory conditions. Our data showed that all the three species examined could be considered good bioaccumulators for the heavy metals tested. L. riparium was the most resistant species and the most effective in accumulating Cu, Zn, and Pb, whereas L. minor was the most effective in accumulating Cd. Cd was the most toxic metal, followed by Pb, Cu, and Zn. At the ultrastructural level, sublethal concentrations of the heavy metals tested caused induced cell plasmolysis and alterations of the chloroplast arrangement. Heavy metal removal experiments revealed that the three macrophytes showed excellent performance in removing the selected metals from the solutions in which they are maintained, thus suggesting that they could be considered good candidates for wastewaters remediation purpose.