镉超富集植物商陆及其富集效应

超累积植物筛选是重金属污染土壤植物提取修复的基础和核心问题,同时也是污染环境植物修复的难点及前沿。对株洲市铅锌冶炼厂生产区生长的8种不同的植物进行了采样和调查。通过生物量测定和植物体内镉质量分数分析,发现商陆(Phytolaccaacinosa)体内镉质量分数较高,生物量大,且呈现地上部的质量分数大于地下部的规律。通过室外盆栽模拟试验,进一步研究商陆对土壤中镉污染的忍耐、积累能力,以检验这种植物修复Cd污染土壤的可能性及其潜力。结果表明,在Cd污染水平大于50mg·kg-1条件下,商陆茎及叶的Cd含量分别超过了100mg·kg-1这一公认Cd超积累植物应达到的临界含量标准,其地上部Cd含量大于其根部Cd含量,且地上部Cd富集系数大于1。与对照相比,植物的生长未受到抑制,商陆对Cd的富集符合Cd超积累植物的基本特征。同时,利用吸收量系数对商陆的镉去除能力和富集特征进行了评价判断,证实商陆是一种Cd超积累植物,这为镉污染土壤的植物修复提供了一种新的种质资源。     

3种镉超富集植物毛状根体系对镉胁迫响应的比较

近年来,转基因毛状根组织被越来越多地应用于重金属和有机污染物的植物修复技术研究中,已成为进行污染物毒性响应机制研究的便捷的实验室工具。为了探究龙葵、油菜、芥菜3种镉(cadmium,Cd)超富集植物对Cd毒性胁迫响应的差异,以诱导出的3种植物毛状根为研究材料,从毛状根的生长状态、富集Cd的能力、根组织细胞的凋亡程度和抗氧化酶活性等方面进行了探讨。结果表明:Cd浓度为0~50μmol·L-1时,龙葵、油菜、芥菜毛状根受Cd毒害的影响都不明显;Cd浓度为75~100μmol·L-1时,龙葵、油菜、芥菜毛状根均表现出对Cd胁迫的防御响应。在较高的Cd浓度(100μmol·L-1)下,龙葵毛状根的生物量受Cd毒害的影响最小,芥菜次之,油菜受影响最大;同时龙葵毛状根富集的Cd含量最高(745.0μg·g-1),芥菜次之(681.4μg·g-1),油菜最差(505.2μg·g-1)。龙葵、油菜、芥菜毛状根在Cd胁迫下的细胞凋亡水平均随Cd浓度的升高而升高,当Cd浓度为100μmol·L-1时,龙葵毛状根比油菜和芥菜毛状根的细胞凋亡程度均低。同时3种植物毛状根在不同浓度Cd处理下抗氧化酶活性的变化有一定差异。从上述结果综合来看,龙葵毛状根受Cd毒害的影响最小、富集Cd的能力最好,是进一步开展Cd超富集植物转基因改造研究的较好的实验室载体。     

镉胁迫下柳树5个无性系生理特性的变化

柳树(Salix)以其自己特有的生物学特性,对环境Cd污染具有一定的吸收蓄积能力.以5个金丝柳无性系为材料,用盆栽方法研究了镉胁迫对柳树生理特性的影响,以主成分分析法分析7个生理指标的重要性,并以隶属函数法评价了金丝柳5个无性系镉耐性的强弱.研究结果表明,在10～150 mg.kg-1镉胁迫范围内,金丝柳5个无性系生理变化程度不同,但变化规律基本一致.在Cd胁迫下,金丝柳各无性系植株生长受到抑制;叶绿素质量分数降低;叶片细胞膜透性和游离脯氨酸积累量增加,丙二醛和可溶性蛋白质量分数降低.主成分分析表明本试验中选取的5个成分在评价柳树Cd耐性方面有重要作用,它们分别是地径生长率、叶绿素质量分数、MDA质量分数、脯氨酸质量分数和可溶性蛋白质量分数.用隶属函数法以评定金丝柳5个无性系Cd耐性的强弱顺序为4号＞6号＞5号＞7号＞2号.     

2个镉耐性差异箭舌豌豆品种中镉的化学形态及亚细胞分布

通过溶液培养实验,研究了镉胁迫下2个箭舌豌豆(Vicia sativa)品种(镉耐性品种L3,镉敏感品种ZM)中镉的积累、镉的亚细胞分布和化学形态以及非蛋白巯基化合物(NPTs)的响应。结果表明2个箭舌豌豆品种根较地上部积累更多的镉。镉在箭舌豌豆根、茎和叶中主要分布于可溶性组分,敏感品种ZM根中可溶性组分的镉含量和占总镉的比例显著高于耐性品种L3。细胞壁结合镉占总镉的比例在2个品种中均为叶>茎>根。镉在箭舌豌豆根和茎内主要以去离子水(d-H2O)提取态和1 mol·L-1氯化钠(Na Cl)提取态存在,ZM根中d-H2O提取态镉的含量和比例显著大于L3。箭舌豌豆叶中镉主要以2%醋酸(HAc)提取态存在。ZM叶中80%乙醇提取态镉的比例大于L3,0.6 mol·L-1盐酸(HCl)提取态镉和残渣态镉的比例小于L3。2个品种根和茎中NPTs的含量在镉胁迫下显著升高,ZM根中NPTs的含量显著大于L3。研究结果表明,箭舌豌豆镉解毒的主要机制包括限制镉由根部向地上部转运和液泡隔离。此外,根和茎中镉与有机酸结合和NPTs螯合,叶中镉以移动性低、毒性低的形态存在也是箭舌豌豆镉解毒的重要机制。ZM较L3根中更多镉以移动性高的形态存在,L3较ZM叶中更多镉以难移动的形态存在,是L3较ZM具有更高镉耐性的重要原因。     

土壤中植物有效态镉提取方法比较

通过温室盆栽试验研究了滩潮土、青紫泥田和黄泥砂田中添加镉对青菜镉吸收的影响,评价了人工螯合剂、无机盐和硝酸溶液对污染土壤中镉的浸提性及其植物有效性.结果表明,青菜地上部镉与土壤镉含量呈非线性关系.土壤pH值和碳酸钙含量是影响镉植物有效性的主要因素,青菜对镉的吸收与土壤pH呈显著负相关.在土壤镉含量相同条件下,黄泥砂田、青紫泥田、滩潮土3种土壤中青菜地上部镉含量依次降低.青菜地上部镉含量与0.43mol·L-1HNO3、0.05mol·L-1EDTA和0.01mol·L-1CaCl2提取态镉均呈显著相关(r2=0.73～0.96).笔者认为,这3种提取剂提取的土壤镉可视为植物有效态镉.     

忍冬--一种新发现的镉超富集植物

镉(Cd)是毒性最强的重金属元素之一,具有稳定、积累和不易消除等特性,进入土壤环境中易被植物吸收,并可通过食物链进入人体,在人体内不断积累,严重威胁人体健康及生命安全。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。植物修复技术的核心是找到超富集植物(Hyperaccumulator),但现已知的超富集植物往往存在生物量低、生长缓慢、地域性较强和修复时间较长等缺陷,且研究对象多集中矿区及草本植物,而对木本植物的研究甚少,因此有必要针对这一问题开展相关研究以丰富超富集植物的种类。为此,本文采用水培和土培相结合的试验方法,研究木本植物忍冬Lonicera japonica Thunb.对不同浓度镉(Cd)的生长响应及积累特性。结果表明：不同浓度的Cd处理对忍冬的生长并未造成毒害症状,表现为其根部和地上部生物量与对照相比并无显著差异。无论水培还是土培生长条件下,在较高浓度的Cd处理下,忍冬仍能保持正常生长,表现出很好的耐性。在水培条件下,当营养液中Cd处理浓度为25 mg·L-1时,忍冬地上部中Cd含量接近300.00μg·g-1;而在土培条件下,当土壤中Cd处理浓度为50 mg·kg-1时,其地上部中Cd含量仍远远高于Cd超富集植物的临界含量标准,即地上部分富集Cd超过100μg·g-1,且其具有较高的耐性系数（index of tolerance,IT均超过0.80）和富集系数（bioaccumulation factor,BF均远超过1.00）,这表明忍冬具备了Cd超富集植物的特征,是一种新发现的Cd超富集植物,将其应用于Cd污染土壤修复具有重要的现实意义。     

镉和铁及其交互作用对植物生长的影响

镉是植物的非必需元素，而铁是植物生长发育过程中必不可少的元素。虽然这两种元素对植物的作用是截然相反的，但是它们在植物体内存在着交互作用关系，相互影响着对方功能的发挥。供给植物足够的铁可极大地缓解植物的镉污染毒害，利于植物合成更多的叶绿素，促进光合作用进行，降低镉对氨基酸、蛋白质合成以及酶活性的影响。相反，镉污染将诱导植物的铁营养缺乏。渍水植物根表形成的铁氧化物胶膜可促进植物对镉的吸收。     

鱼腥草对土壤中镉的富集及根系微生物的促进作用

通过采集自然条件的鱼腥草和未受污染的土壤,在实验室条件下培育,以及利用镉的筛选,培养出土壤菌悬液,研究了鱼腥草Huttuynia cordata对土壤中镉的富集作用,以及经过根系微生物处理后放线菌对富集后转移的促进作用。结果表明,根部经过微生物处理的鱼腥草地上部（土壤含镉200 mg·kg^-1）有最高的含镉浓度和最大的富集量,分别是是对照组的20倍和50倍。土壤含镉50 mg·kg^-1时,鱼腥草地上部与地下部镉富集量的比例是2.5,高于对照组（1.5）。而当土壤含镉200 mg.kg^-1时,经过处理的鱼腥草地上部与地下部镉含量之比是未经处理的2倍。所以,鱼腥草对土壤中的镉有很强的富集作用,且在根系微生物的促进下,地下部的镉能更有效地转移到地上部,大大加强植物的修复效率;且与其他的诸如添加化学螯合剂等方法相比,土壤根系微生物能更好地适应植物根系环境,更不会对土壤本身的微生态系统造成二次污染。所以研究根系环境中微生物、根系、土壤酶、金属离子等的相互影响关系,将是土壤重金属植物修复的另一重要领域。     

锌胁迫下宽叶山蒿的耐性与富集特征

采用室内盆栽试验研究宽叶山蒿(Artemisia stolonifera)在Zn胁迫条件下的耐性和富集特征.结果表明,当w(Zn)≤500 mg·kg-1时,宽叶山蒿株高、根长和生物量均先随土壤中Zn浓度的升高而增加,之后则随Zn浓度的升高,Zn对宽叶山蒿的胁迫作用渐趋明显.与对照相比,当w(Zn)为1 500～3 500 ng·kg-1时,宽叶山蒿根部POD活性显著增大,当w(Zn)为3 500 mg·kg-1时,根部CAT活性显著增大;而叶片POD和CAT活性整体变化较不明显.宽叶山蒿根部和地上部w(Zn)最大值分别为999和3214mg·kg-1,对Zn的最大富集量分别为3.40和17.33 mg·盆-1.宽叶山蒿地上部对Zn的富集系数和迁移系数分别为0.26～0.82和0.65 ～1.05.可见,宽叶山蒿是一种对Zn具有较强耐性和富集潜力的植物,可用于Zn污染土壤的修复.     

Comparisons in subcellular and biochemical behaviors of cadmium between Iow-Cd and high-Cd accumulation cultivars of pakchoi （Brassica chinensis L.）

Subcellular distributions and chemical forms of cadmium （Cd） in the leaves, stems and roots were investigated in low-Cd accumulation cultivars and high-Cd accumulation cultivars ofpakchoi （Brassica chinensis L.）. Root cell wall played a key role in limiting soil Cd from entering the protoplast, especially in the low-Cd cultivars. The high-Cd cultivars had significantly higher leaf and stem Cd concentrations than the low-Cd cultivars in cell wall fraction, chloroplast/trophoplast fraction, organelle fraction and soluble fraction. In low-Cd cultivars, which were more sensitive and thus had greater physiological needs of Cd detoxification than high-Cd cultivars, leaf vacuole sequestrated higher proportions of Cd. Cd in the form of pectate/protein complexes （extracted by 1 tool. L~ NaC1） played a decisive role in Cd translocation from root to shoot, which might be one of the mechanisms that led to the differences in shoot Cd accumulation between the two types of cultivars. Furthermore, the formation of Cd- phosphate complexes （extracted by 2% HAc） was also involved in Cd detoxification within the roots of pakchoi under high Cd stress, suggesting that the mechanisms of Cd detoxification might be different between low- and high-Cd cultivars.     

植物耐盐研究概况与展望

概述了植物耐盐性有关领域的研究进展，包括环境因素对植物耐盐性影响、植物耐盐种质资源评价、植物耐盐的生理生化基础、植物耐盐分子生物学和耐盐植物的开发利用等5个方面。同时对植物耐盐性研究的意义和展望进行了简要探讨。     

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。     

Characterisation of early responses to cadmium in roots of Salix matsudana Koidz

This study deals with the characterisation of early responses of roots of Salix matsudana in respect to oxidative stress, subcellular distribution, and chemical forms when exposed to 50 μmol/L Cd. Within 12 h, the root length is reduced and the contents of O₂^??, H₂O₂, and malondialdehyde are increased by 49%, 43%, and 35%. Cd is mainly retained in the cell walls; small amounts are distributed into other cell organelles. The largest proportion of Cd is found in the NaCl extractable, pectate-, and protein-integrated fraction.     

Characterization of the genes involved in nitrogen cycling in wastewater treatment plants using DNA microarray and most probable number-PCR

To improve nitrogen removal performance of wastewater treatment plants (WWTPs), it is essential to understand the behavior of nitrogen cycling communities, which comprise various microorganisms. This study characterized the quantity and diversity of nitrogen cycling genes in various processes of municipal WWTPs by employing two molecular-based methods:most probable number-polymerase chain reaction (MPN-PCR) and DNA microarray. MPN-PCR analysis revealed that gene quantities were not statistically different among processes, suggesting that conventional activated sludge processes (CAS) are similar to nitrogen removal processes in their ability to retain an adequate population of nitrogen cycling microorganisms. Furthermore, most processes in the WWTPs that were researched shared a pattern:the nirS and the bacterial amoA genes were more abundant than the nirK and archaeal amoA genes, respectively. DNA microarray analysis revealed that several kinds of nitrification and denitrification genes were detected in both CAS and anaerobic-oxic processes (AO), whereas limited genes were detected in nitrogen removal processes. Results of this study suggest that CAS maintains a diverse community of nitrogen cycling microorganisms; moreover, the microbial communities in nitrogen removal processes may be specific.

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Environmental effects and risk control of antibiotic resistance genes in the organic solid waste aerobic composting system: A review

• ARGs were detected in livestock manure, sludge, food waste and fermentation dregs. • The succession of microbial community is an important factor affecting ARGs. • Horizontal transfer mechanism of ARGs during composting should be further studied. Antibiotic resistance genes (ARGs) have been diffusely detected in several kinds of organic solid waste, such as livestock manure, sludge, antibiotic fermentation residues, and food waste, thus attracting great attention. Aerobic composting, which is an effective, harmless treatment method for organic solid waste to promote recycling, has been identified to also aid in ARG reduction. However, the effect of composting in removing ARGs from organic solid waste has recently become controversial. Thus, this article summarizes and reviews the research on ARGs in relation to composting in the past 5 years. ARGs in organic solid waste could spread in different environmental media, including soil and the atmosphere, which could widen environmental risks. However, the conventional composting technology had limited effect on ARGs removal from organic solid waste. Improved composting processes, such as hyperthermophilic temperature composting, could effectively remove ARGs, and the HGT of ARGs and the microbial communities are identified as vital influencing factors. Currently, during the composting process, ARGs were mainly affected by three response pathways, (I) “Microenvironment-ARGs”; (II) “Microenvironment-microorganisms-ARGs”; (III) “Microorganisms-horizontal gene transfer-ARGs”, respectively. Response pathway II had been studied the most which was believed that microbial community was an important factor affecting ARGs. In response pathway III, mainly believed that MGEs played an important role and paid less attention to eARGs. Further research on the role and impact of eARGs in ARGs may be considered in the future. It aims to provide support for further research on environmental risk control of ARGs in organic solid waste.     

金属基工程纳米颗粒与水生高等植物的相互作用：研究现状综述

如今释放到水体环境中的工程纳米颗粒(ENP)数量与日俱增。为确保生态健康,需要进行相关的风险评估。本文综述了金属基ENP与水生高等植物之间的相互作用,找到了信息缺口并提出对未来研究的构想,为在该领域内的进一步探索提供了基础。本文讨论集中在以下3点：1. ENP的生物利用性;2. 生物对ENP的摄取、消化、转移以及生物累积;3. ENP对水生高等植物的毒性效果。由于ENP自身特性所带来的影响不明确以及水质状况记载情况不佳,ENP的摄取及相关动力学方面存在着很大的信息差距。分解似乎是驱动ENP生物累积的一种关键机制,然而纳米颗粒却常常被一些有着极少内化作用的植物的表面所吸收。然而,关于ENP在植物内的内化作用鲜有记载,因此纳米颗粒的内化作用对于生物累积及毒性的影响尚不明确。即使金属基ENP的纳米毒性已被报道,分解依然被认为是其毒性的主要机制。为推动该领域内的研究发展,未来的研究需结合ENP自身特性的影响、水体的理化参数以及它们之间的相互作用。相互作用对于ENP的生物利用性和对水生高等植物健康的风险都有重要影响。为了快速追踪类似数据的产生,我们建议测试方案趋向一致化。
精选自Melusi Thwala, Stephen J. Klaine, Ndeke Musee. Interactions of metal-based engineered nanoparticles with aquatic higher plants: a review of the state of current knowledge. Environmental Toxicology and Chemistry: Volume 35, Issue 7, pages 1677–1694, July 2016. DOI: 10.1002/etc.3364
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3364/full
     

Relationship between heavy metal concentrations of herbaceous plants and soils at four Pb-Zn mining sites in Yunnan, China

This paper studied the relationship between heavy metal concentrations of herbaceous plants and soils at four Pb-Zn mining sites in Yunnan, China. 50 herbaceous plant samples of 9 plant species from 4 families and 50 soil samples were collected and then ana1yzed for the tota1 concentrations of Pb, Cd, and Zn. The results showed that the average concentrations of Pb, Cd, and Zn in soil samples were 3772.83, 168.81, and 5385.65 mg/kg, respectively. The average concentrations of Pb, Cd, and Zn were 395.68, 28.14, and 1664.20 mg/kg in the shoots, and 924.12, 57.25, and 1778.75 mg/kg in the roots, respectively. Heterospecific plants at the same site and conspecific plants at various sites had different average levels of Pb, Cd, and Zn, both in the shoots and the roots. Enrichment coefficients of Pb, Cd, and Zn were greater than 1 in 2, 3, and 9 herbaceous plant samples, respectively. Translocation factors of Pb, Cd, and Zn were greater than 1 in 10, 17, and 25 herbaceous plant samples, respectively. In all 50 samples, the concentrations of Pb, Cd, and Zn between the shoots and the roots, the shoots, and the soils, and the roots and the soils had significant positive relationships.     

Presence,dissemination and removal of antibiotic resistant bacteria and antibiotic resistance genes in urban drinking water system: A review

Reviewed the change of ARGs and ARB in full-scale urban drinking water systems. Conventional processes are more promising than BAC process in ARGs removal. Mechanisms of ARGs enrichment and spread in BAC filter and DWDSs are discussed. Raise the need of future research on ARGs and ARB change in building plumbing systems. Antibiotic resistance in aquatic environment has become an important pollution problem worldwide. In recent years, much attention was paid to antibiotic resistance in urban drinking water systems due to its close relationship with the biosafety of drinking water. This review was focused on the mechanisms of antibiotic resistance, as well as the presence, dissemination and removal of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in the urban drinking water system. First, the presence of ARB and ARGs in the drinking water source was discussed. The variation of concentration of ARGs and ARB during coagulation, sedimentation and filtration process were provided subsequently, in which filtration was proved to be a promising technology to remove ARGs. However, biological activated carbon (BAC) process and drinking water distribution systems (DWDSs) could be incubators which promote the antibiotic resistance, due to the enrichment of ARGs and ARB in the biofilms attached to the active carbon and pipe wall. Besides, as for disinfection process, mechanisms of the inactivation of ARB and the promotion of conjugative transfer of ARGs under chlorine, ozone and UV disinfection were described in detail. Here we provide some theoretical support for future researches which aim at antibiotic resistance controlling in drinking water.