重金属超富集植物及植物修复技术研究进展

植物修复技术（Phytoremediation)是近年来发展起来的一种主要用于清除土壤重金属污染的绿色生态技术,重金属超富集植物（hyperaccumulator)及植物修复技术是当前学术界研究的热点领域,目前虽已有Cd、Co、Cr、Cu、Mn、Ni、Pb、Zn等超富集植物发现的报道,但尚无一例报道来自于中国,中国具有广袤的国土面积、丰富的植物类型和多种（处）古老的矿山开采与冶炼场所,在中国开展超富集植物的寻找,研究与开发工作,将会有重要突破,并具有重要的理论与实践意义,本文拟就国内外在这一领域的研究进展作一简要综述。     

植物重金属超富集机理研究进展

植物超富集重金属机理主要涉及植物对金属离子高的吸收、运输能力,区域化作用及螯合作用等方面,其中跨膜运载蛋白的表达、调控对重金属超富集这一特性起了关键作用。金属阳离子运载蛋白家族主要包括CDF家族、NRAMP家族和ZIP家族等,在超富集植物中已克隆出多个家族的金属运载蛋白基因,这些基因的过量表达对重金属在细胞中的运输、分布和富集及提高植物的抗性方面发挥了重要作用。综述了近年来研究重金属超富集植物吸收、转运和贮存Zn、Ni、Cd等重金属的生理和分子机制所取得的主要进展。     

超富集植物对重金属耐受和富集机制的研究进展

超富集植物对重金属耐受和富集机制的研究成为近年来植物逆境生理研究的热点,在简要总结细胞壁沉淀、重金属螯合效应、酶活性机制和细胞区室化作用的基础上,概述了超富集植物对重金属的耐受机制,讨论了重金属跨根细胞质膜运输,共质体内运输、木质部运输和跨叶细胞膜运输的富集过程。     

几种重金属(Pb、Zn、Cd、Cu)的超富集植物种类及增强植物修复措施研究进展

近年来土壤重金属污染问题越来越严重, 植物修复技术以其安全、廉价的特点正成为研究和开发的热点, 国内外对利用超富集植物来修复土壤重金属污染的研究已有大量报道。对超富集植物概念的提出及超富集植物吸收富集重金属的机理进行了归纳总结, 主要就铅、锌、镉和铜四种重金属超富集植物的相关研究进展进行了分类、归纳与总结, 同时还对增强植物修复效果的措施进行了探讨, 以期为进一步合理有效利用植物修复土壤主要重金属污染提供一定的参考依据。     

杂草对土壤重金属的富集与含量特征研究

对冶炼厂周围的土壤和杂草中的4种重金属元素含量进行测定和统计。结果表明,杂草不同器官重金属的平均含量由高到低分别为根>叶>茎,重金属在植物体内含量的分布Cu>Zn>Ni>Pb,富集系数由大到小为Zn>Cu>Pb>Ni。看麦娘(Alopecurusaequalis)、菰(Zizania latifolia)、鬼针草(Bidens pilosa)、丁香蓼(Ludwigiaprostrata)、双穗雀稗(Paspalumdistichum)、芦苇(Phragmites australis)等植物的根对Cu有较强的富集能力,其富集系数分别为2.54、2.69、4.82、10.74、7.33和4.60。看麦娘、双穗雀稗、丁香蓼、芦苇、鬼针草的根以及井口边草(Pteris multifida)地下部分和小飞蓬(Conyza canadensis)叶中的Cu含量分别高达813.4、1338、1959.65、840.1、1066.6、2030和334.5 mg·kg-1。水蓼(Ploygonumhydropiper)叶对Pb有较强的富集能力,其富集系数是2.15。丁香蓼、蛇床(Cnidium monnieri)和婆婆纳(Veronica didyma)叶以及野艾蒿(Artemisialavandulaefolia)的茎和叶对Zn有较强的富集能力,富集系数分别是2.28、2.45、3.02、2.25和2.54。杂草重金属含量与土壤中重金属含量的相关性不大。丁香蓼较适合作为重金属Cu、Zn污染地区的恢复植物     

土壤重金属的超富集植物研发利用现状及应用入侵植物修复的前景综述

植物修复作为一种绿色安全技术成为土壤重金属污染治理研究的热点领域之一。综述了当前已筛选用于土壤重金属污染修复的植物种类、研发现状及其应用模式, 总结了植物修复技术存在的问题及面临的困境。在此基础上, 围绕入侵植物生长繁殖快、生物量大、抗逆性强及其对某些重金属的超富集特性, 分析探讨了入侵植物作为土壤重金属污染修复的可行性及应用前景, 并提出对入侵植物修复的后续处理利用思路, 旨为综合利用入侵植物修复土壤重金属污染提供可能的新途径和新方法。     

粤东铅锌尾矿三种优势植物对重金属的吸收和富集特性研究

为探讨铅锌矿废弃地优势植物在重金属污染土壤植物修复中的应用潜力,利用野外采样分析法,从粤东梅县丙村铅锌尾矿区采集其三种优势植物类芦、黄荆、盐肤木的根、茎、叶和土壤样品,测定和分析Pb、Zn、Cu、Cd四种重金属含量.结果表明:该矿区土壤污染严重,Pb、Zn、Cd含量远超土壤环境质量的三级标准,Cu超出二级标准;根际土壤和非根际土壤重金属含量均为Pb＞Zn＞Cu＞Cd,但根际土壤的重金属含量显著低于非根际土壤;这三种植物对Pb、Zn、Cu的转移系数大于1.0,对Cu的富集系数最高,Pb最小,但对四种重金属的富集系数均小于1.0,均未达到超富集植物临界含量标准.三种植物为该矿区的优势植物,说明它们对土壤的重金属污染有很强的耐性,虽然并非典型的超富集植物,但对污染土壤仍有较好的修复效果.     

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。     

植物修复——治理土壤重金属污染的新途径

介绍了重金属污染土壤的植物修复的概念、原理与研究动态以及重金属超积累植物的特性 ,及其在治理污染土壤中的潜力 ,为土壤重金属污染的整治及其生态的修复提出新途径。     

重金属超富集植物东南景天毛状根的诱导

为建立重金属超富集植物东南景天(Sedum alfredii)的毛状根诱导体系,采用发根农杆菌(Agrobacterium rhizogenes)A4侵染叶片,研究了预培养时间、侵染时间和共培养时间对毛状根诱导率的影响。结果表明,东南景天叶片外植体的预培养时间为48 h、农杆菌侵染时间为6 min、共培养时间为48 h是适宜的毛状根诱导时间,毛状根的诱导率可达85%。PCR检测表明诱导的毛状根中存在rol B基因片段。这是东南景天首次建立用发根农杆菌诱导毛状根体系。     

Hyperaccumulators of metal and metalloid trace elements: Facts and fiction

Background

Plants that accumulate metal and metalloid trace elements to extraordinarily high concentrations in their living biomass have inspired much research worldwide during the last decades. Hyperaccumulators have been recorded and experimentally confirmed for elements such as nickel, zinc, cadmium, manganese, arsenic and selenium. However, to date, hyperaccumulation of lead, copper, cobalt, chromium and thallium remain largely unconfirmed. Recent uses of the term in relation to rare-earth elements require critical evaluation.

Scope

Since the mid-1970s the term ‘hyperaccumulator’ has been used millions of times by thousands of people, with varying degrees of precision, aptness and understanding that have not always corresponded with the views of the originators of the terminology and of the present authors. There is therefore a need to clarify the circumstances in which the term ‘hyperaccumulator’ is appropriate and to set out the conditions that should be met when the terms are used. We outline here the main considerations for establishing metal or metalloid hyperaccumulation status of plants, (re)define some of the terminology and note potential pitfalls.

Conclusions

Unambiguous communication will require the international scientific community to adopt standard terminology and methods for confirming the reliability of analytical data in relation to metal and metalloid hyperaccumulators.     

Two Na+ and Cl- Hyperaccumulators of the Chenopodiaceae

The authors found five sodium (Na ) and chloride (Cl-) hyperaccumulating halophytes in the Temperate Desert of Xinjiang, China and studied two of them (Suaeda salsa (L.) Pall. and Kalidium folium (Pall.) Moq.). K. folium and S. salsa had a NaCl content of 32.1% and 29.8%, respectively, on a dry weight basis. X-ray microanalysis of the Na in the vacuole, apoplasts and cytoplasm of the two plants indicated a ratio of 7.3:5.6:1.0 in K. folium and 7.3:6.6:1.0 in S. salsa. These data show that K. folium and S. salsa both have a high Na and Cl-accumulating capacity, which is related to high activity oftonoplast H -ATPase and H -PPase.     

Hyperaccumulators, arbuscular mycorrhizal fungi and stress of heavy metals

Use of plants, with hyperaccumulating ability or in association with soil microbes including the symbiotic fungi, arbuscular mycorrhiza (AM), are among the most common biological methods of treating heavy metals in soil. Both hyperaccumulating plants and AM fungi have some unique abilities, which make them suitable to treat heavy metals. Hyperaccumulator plants have some genes, being expressed at the time of heavy metal pollution, and can accordingly localize high concentration of heavy metals to their tissues, without showing the toxicity symptoms. A key solution to the issue of heavy metal pollution may be the proper integration of hyperaccumulator plants and AM fungi. The interactions between the soil microbes and the host plant can also be important for the treatment of soils polluted with heavy metals.     

基因专一性鸡卵黄抗体(IgY)的研究及应用

用抗原免疫鸡,从鸡卵黄中获取特异多克隆IgY抗体,是一条高产量、低成本的简便快速途径。IgY与哺乳动物抗体IgG相比具有许多突出的优点,使IgY在现代免疫学中已得到广泛应用。采用基因免疫方法制备的基因专一性IgY抗体,在免疫分析、寻找药靶和生物标记物、制备新抗体等方面,必有进一步的应用。     

铝超积累植物和铝排斥植物吸收和累积铝的机理

研究了香港茶园天然生态系统中铝超积累植物和铝排斥植物包括茶树（Camellia sinensis L.）、多花野牡丹（Melastoma affine L.）、假苹婆（Sterculia lanceolata L.）、大罗伞紫金牛（Ardisia crenata L.）、相思树（Acacia formosa L.）和红楠（Machilus thunbergii Machilus thunbergii L.）对铝吸收和累积的机理。6种植物新鲜根和茎的pH值变化范围为3-6,不同部位全铝含量变化幅度为13-12810mg/kg（干重,下同）。新鲜植物组织的pH值是控制植物对铝吸收、转运和累积的最重要的因素。植物中的铝浓度随其pH值降低而显著增加。供试6种植物可分为两组：一组是铝排斥植物,其pH值大约6,叶中含铝量范围为17-151mg/kg,包括假苹婆、大罗伞紫金牛、相思树和红楠;另一组是铝超积累植物,其pH值为3和4.5,叶中含铝量范围为7820-12810mg/kg,包括茶树和多花野牡丹。铝超积累植物新鲜根中水溶性铝与全铝的比例（0.11-0.88）高于铝排斥植物根中的比例（0.04-0.07）。相同趋势可见于茎和叶中,特别在多花野牡丹茎叶中。结果表明：新鲜根、茎和叶中水溶性铝与全铝的比例高可以增加植物从土壤-植物系统中铝的迁移速率,导致较高的铝吸收累积。根际和非根际土壤的pH值有显著差异。通常,象多花野牡丹一样的铝超积累植物,其组织pH值低,降低了根限pH,使土壤中铝更容易吸收。铝排斥植物增根际土壤的pH值,以避免根对铝的高量吸收。     

The Use of Theory in Behavioural Research

A survey of recent publications in behavioural biology suggests that research in this field often lacks a formal approach linking theory and empiricism, which implies that there is scope for improvement. Frequently, hypotheses guiding empirical work are merely based on plausibility arguments, which is not necessarily wrong and may be useful especially at the early stages of an investigation. Behavioural studies based on a theoretical framework usually test qualitative predictions from a general model either with data from natural situations or by experimental scrutiny. Rarely, a quantitative approach is used where a model is parameterized by existing data and therefore generates precise, testable predictions. In general, there is a lack of awareness that much more is to be learnt from a mismatch between predictions and data than from accordance. The latter is prone to cause the ‘pseudo‐proof fallacy’, which is widespread in behavioural ecology. Behavioural physiology, on the other hand, often suffers a lack of proper theoretical models. Much can be gained in both fields if empiricists and theoreticians collaborate more closely towards the ultimate aim – to unravel the mechanisms of behaviour at both, ultimate and proximate levels.     

Screening of Native Hyperaccumulators at the Huayuan River Contaminated by Heavy Metals

Plant, soil, and sediment samples were taken from the Fuqiao area within the Huayuan River basin in South China. Concentrations of manganese, zinc, cadmium, and lead in the samples were measured, and the characteristics of the plant samples to absorb, transfer, and accumulate the target metals were analyzed. It was indicated that the concentrations of target metals in 13 plant samples greatly exceeded the background values of target metals in plants over the world, and that the plant species might evolve to the accumulating ecotypes for the target metals under the long-term stress from the contaminated environment. Among 13 plant species, Alternanthera philoxeroides exhibited the highest accumulation capacities for the target metals, amounting to 6511, 13,784, 155, and 104 mg/kg in its shoots for manganese, zinc, cadmium, and lead, respectively. Its bioaccumulation coefficients for manganese, zinc, cadmium, and lead were 5.08, 49.23, 36.78, and 34.81, respectively, and its transfer factors for manganese, zinc, cadmium, and lead were 7.53, 3.19, 7.38, and 1.29, respectively. The results showed that Alternanthera philoxeroides satisfied the criteria for the hyperaccumulator for zinc and cadmium, and that it might be a potential native plant species for phytoremediation of the contaminated soil, sediment, and river water by the target metals within the basin.