高速公路路域土壤重金属污染及植物修复研究进展

高速公路路域土壤重金属污染在土壤重金属污染中占较大的比例,介绍了路域土壤重金属的种类、来源,分析了国内外重金属污染研究状况,总结了重金属污染的危害,详细论述了重金属污染的植物修复技术,并提出该技术存在的问题与今后的发展方向,结果表明,高速公路路域土壤重金属污染治理技术是一项成本低、效果好、不破坏环境的修复技术。     

玉米对重金属胁迫的响应及其在植物修复中的应用

综述了玉米作为潜在植物修复材料对单一和复合重金属污染的胁迫响应及其机理、各种辅助措施（接种菌根,添加螯合剂,适当农艺措施等）促进玉米对重金属的修复效率等,提出了玉米用于重金属污染修复存在的问题及今后的研究方向。     

油菜对Cd污染土壤的植物修复

通过盆栽试验,对"秦油8号"(Brassica rlapus L."Qinyou No.8")在不同水平Cd污染下的耐性以及富集指标进行测定,并施加不同水平螯合剂对油菜的修复效果进行强化.结果表明,低水平Cd处理对油菜的株高、干质量、叶绿素含量等有轻微的促进作用,而高水平Cd则表现出抑制作用,在土壤Cd添加量为80mg/kg时,油菜的株高、干质量、叶绿素总量分别比对照降低了20.5%、43.5%和64.3%.油菜体内脯氨酸含量与Cd添加量呈现显著的正相关性,比对照升高了23倍,表现出一定的耐性.油菜体内Cd积累规律为根部大于地上部.各部位含Cd量以及每盆油菜吸收Cd总量都随土壤Cd添加量的增加而递增,在土壤Cd添加量为40 mg/kg时达到最大值.此后则会下降.施加3种水平螯合剂均提高了油菜对Cd的吸收,但高水平的螫合剂处理却导致油菜死亡.相比之下,中等水平螯合剂处理下,油菜对Cd的吸收效率较高.可见,秦油8号具有修复Cd污染土壤的潜力.     

长坡尾矿坝植物修复过程中土壤脲酶活性变化

采集广西南丹县长坡矿尾矿坝0~20 cm表土,测定了土壤pH、有机质、碱解N含量和脲酶活性。采用数理统计的相关分析方法,探究重金属污染区的植被自然恢复和植物修复过程中,土壤脲酶活性与土壤肥力水平的关系,为重金属污染区土壤的生态恢复提供理论依据。结果表明:长坡尾矿坝土壤有机质含量较低,土壤肥力状况仍然较差。土壤脲酶活性与土壤碱解氮含量之间呈正相关,与土壤有机质含量相关性不大。在尾矿坝植被自然恢复过程中,五节芒、苔草、割鸡芒等植物根际土脲酶活性的平均值相对较高,而狗牙根、类芦根际土的脲酶活性相对较低。如果不引进外来物种,只选择该尾矿坝上自然生长的植物作为生态恢复的物种,五节芒、割鸡芒和苔草等植物应作为优先选择的物种,类芦、狗牙根等植物可作为第2阶段修复的物种。     

Molecular diversity of arbuscular mycorrhizal fungi associated with an Mn hyperaccumulator—Phytolacca americana,in Mn mining area

Arbuscular mycorrhizal fungi (AMF) have great potential for assisting metal-hyperaccumulating plants in the remediation of contaminated soils. However, little information is available about the symbiosis and community composition of AMF associated with manganese (Mn) hyperaccumulator, such as Phytolacca americana, growing on Mn-contaminated soils under natural conditions. Therefore, the objective of this study was to analyze AMF diversity and community composition in P. americana roots growing at an Mn mining site. Molecular techniques were used to analyze AMF community composition and phylogenetic relationship in P. americana roots sampled from three Mn mine spoils and one adjacent reference areas. Results obtained showed that mycorrhizal symbionts successfully established even in the most heavily Mn-polluted sites. Root colonization and AMF diversity were significantly negatively correlated with total and extractable Mn concentrations. Principal component analysis (PCA) revealed that Mn contamination impacted AMF diversity, and shaped AMF community structure. Phylogenetic analyses demonstrated that all species were affiliated with Glomus, suggesting that Glomus was the dominant genus in this AMF community. Some unique sequences that occurred exclusively in heavily polluted sites associated with P. americana may belong to symbiotic fungi with great potential for improving the phytoremediation efficiency of Mn-contaminated soils.     

Soil microbial response during the phytoremediation of a PAH contaminated soil

The aim of this trial was to quantify and compare the responses of soil microbial communities during the phytoremediation of polycyclic aromatic hydrocarbons (PAHs) in a laboratory trial. The experiment was conducted in 1-kg pots and planted treatments consisted of a mixed ryegrass (Lolium perenne) and white clover (Trifolium repens) sward together with a rhizobial inoculum (Rhizobium leguminosarum bv. trifolii). Throughout the 180-d experiment soil microbial biomass and communities of PAH degraders were monitored. PAH degradation was enhanced in planted treatments that received a rhizobial inoculum. Microbial biomass was enhanced in planted treatments, but there were no significant differences between treatments that had received a rhizobial inoculum and those that had not. However, numbers of PAH degraders were greater in the treatment that had received a rhizobial inoculum.     

几种豆科、禾本科植物对多环芳烃复合污染土壤的修复

通过盆栽试验,研究了几种豆科植物与禾本科植物对多环芳烃(PAHs)复合污染土壤的修复作用。结果显示,90天后8种植物对土壤中PAHs均有不同程度降解效果,其中紫花苜蓿和多年生黑麦草对土壤PAHs的去除率分别达48.4%、46.8%,且对3环PAHs去除较为彻底,对4环及4环以上的PAHs去除效果较差。8种供试植物对PAHs均有一定的吸收、富集与转运的能力,紫花苜蓿和多年生黑麦草对土壤PAHs的生物富集系数分别为0.096、0.085,其提取修复效率为0.017%和0.013%。可见,紫花苜蓿和多年生黑麦草具有较好的根际修复潜力。     

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。     

间套种及化学强化修复重金属污染酸性土壤——长期田间试验

为了检验重金属污染土壤间套种修复技术的长期实际应用效果,在大田条件下将东南景天(Sedum alfredii Hance)与玉米(Zea mays)间套种,并设置加入柠檬酸与EDTA混合添加剂的处理,以及单种东南景天作为对照,通过5次田间试验(约3 a),连续监测植物产量、重金属含量以及土壤重金属变化情况。结果表明,各处理土壤镉、锌随着试验的进行逐步下降,套种和套种+混合添加剂处理经过5次种植后土壤达到国家土壤环境质量二级标准,土壤镉从1.21~1.27 mg kg-1降为0.29~0.30 mg kg-1;锌从280~311 mg kg-1降为196~199 mg kg-1;但是土壤铅在试验前后没有显著变化。混合添加剂未表现出强化东南景天提取重金属的效果。东南景天重金属浓度和提取效率没有出现逐年下降的现象。单种东南景天地上部生物量在后4次试验中均较套种高,重金属的总提取量也较高。然而,间套种可生产符合饲料卫生标准的玉米籽粒,第4季达到食品卫生标准。从收获的东南景天计算得到的提取量占土壤镉下降的贡献率为32.5%~36.5%,玉米提取仅占0.47%~0.60%,其余63.0%~66.9%为淋溶等其他因素的作用;锌也相似。表明在该酸性(pH4.7)土壤上,Cd/Zn向下淋溶和东南景天提取均起重要作用。     

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。