柳属与杨属植物远缘嫁接研究

为了探索植物远缘嫁接成功的可能性及嫁接体的观赏特性,进行了柳属与杨属植物的属间远缘嫁接组合试验。结果表明：枝接或芽接均可使柳树／杨树或杨树／柳树嫁接成活,其中采用改良插皮接,旱柳／沙兰杨嫁接成活率较高,达90％以上,嫁接组合生长良好,6年内未出现后期不亲和现象,但沙兰杨／旱柳组合在嫁接后会出现“小脚”现象;垂柳／小叶杨、金丝垂柳／小叶杨在秋季芽接．成活率也较高,达70％以上,且嫁接体愈合良好。但是,以柳属植物为砧木,小叶杨为接穗,嫁接组合的成活率较低,仅10％～16％。柳属与杨属植物嫁接体具有较高的观赏性,可望在园林绿化中得到应用,创造新奇的景观。     

Phytoremediation of mine tailings in temperate and arid environments

Phytoremediation is an emerging technology for the remediation of mine tailings, a global problem for which conventional remediation technologies are costly. There are two approaches to phytoremediation of mine tailings, phytoextraction and phytostabilization. Phytoextraction involves translocation of heavy metals from mine tailings to the plant shoot biomass followed by plant harvest, while phytostabilization focuses on establishing a vegetative cap that does not shoot accumulate metals but rather immobilizes metals within the tailings. Phytoextraction is currently limited by low rates of metal removal which is a combination of low biomass production and insufficiently high metal uptake into plant tissue. Phytostabilization is currently limited by a lack of knowledge of the minimum amendments required (e.g., compost, irrigation) to support long-term plant establishment. This review addresses both strategies within the context of two specific climate types: temperate and arid. In temperate environments, mine tailings are a source of metal leachates and acid mine drainage that contaminate nearby waterways. Mine tailings in arid regions are subject to eolian dispersion and water erosion. Examples of phytoremediation within each of these environments are discussed. Current research suggests that phytoextraction, due to high implementation costs and long time frames, will be limited to sites that have high land values and for which metal removal is required. Phytostabilization, due to lower costs and easier implementation, will be a more commonly used approach. Complete restoration of mining sites is an unlikely outcome for either approach.     

Amendment-assisted revegetation of mine tailings: improvement of tailings quality and biomass production

Abstract

Mining activities have left a legacy of metals containing tailings impoundments. After mine closure, reclamation of mine wastes can be achieved by restoration of a vegetation cover. This study investigated the impact of biochar (BC), biosolids (BS), humic substances (HS), and mycorrhizal fungi (MF) for improving mine tailings fertility and hydraulic properties, supporting plant establishment, tailings revegetation, and enabling growth of energy crops. We conducted a pot trial by growing willow, poplar, and miscanthus in Pb/Zn/Cu mine tailings untreated or amended with two rates of amendments (low or high input). Biosolids resulted in the most significant changes in tailings properties, neutralizing pH and increasing organic carbon, nutrient concentrations, cation exchange capacity, water retention, and saturated hydraulic conductivity. The greatest increase in energy crops production was also observed in BS treatments enabling the financial viability of mine reclamation. Although BC resulted in significant improvements in tailings fertility and hydraulic properties, its impact on biomass was less pronounced, most likely due to lower N and P available concentrations. Increases in willow and miscanthus biomass were observed in HS and MF treatments in spite of their lower nutrient content. A pot experiment is underway to assess synergistic effects of combining BS with BC, HS, or MF.     

华南铅锌尾矿生态恢复的理论与实践

介绍了近年来有关华南地区5个铅锌尾矿生态恢复研究领域的主要研究成果。内容包括：铅锌尾矿的理化性质和影响植物定居的限制因子;尾矿酸化的预测与控制;尾矿的基质改良;尾矿自然定居植物的生态对策;重金属耐性植物的筛选与耐性机理;豆科植物在废弃地植被恢复中的作用;尾矿湿地系统的重建及其废水处理效率;土壤种子库在尾矿生态恢复中的作用;尾矿植被恢复的野外中试研究等。同时,也讨论了尾矿废弃地生态恢复的未来研究方向。     

铅锌尾矿上自然定居植物

在凡口1#铅锌尾矿库内共有10种植物自然定居,这些植物主要生长在尾矿库的边缘区域.植物在尾矿上的生长、分布明显受到表层尾矿某些物理性质如稳定状况、含水量等的影响,尾矿中的营养物质含量与植物的生长高度以及群落盖度有一定的关系.杜虹花(Callicarpa pedunculata)体内的Pb、Zn、Cu和Cd含量大小顺序为叶>根>茎,而盐肤木(Rhuschinensis)和美丽胡枝子(Lespedeza     

Integron diversity in heavy-metal-contaminated mine tailings and inferences about integron evolution

Integrons are horizontal gene transfer (HGT) systems containing elements necessary for site-specific recombination and expression of foreign DNA. The overall phylogenetic distribution of integrons and range of genes that can be transferred by integrons are unknown. This report contains an exploration of integrons in an environmental microbial community and an investigation of integron evolution. First, using culture-independent techniques, we explored the diversity of integrons and integron-transferred genes in heavy-metal-contaminated mine tailings. Using degenerate primers, we amplified integron integrase genes from the tailings. We discovered 14 previously undescribed integrase genes, including six novel gene lineages. In addition, we found 11 novel gene cassettes in this sample. One of the gene cassettes that we sequenced is similar to a gene that codes for a step in a pathway for nitroaromatic catabolism, a group of compounds associated with mining activity. This suggests that integrons may be important for gene transfer in response to selective pressures other than the presence of antibiotics. We also investigated the evolution of integrons by statistically comparing the phylogenies of 16S rRNA and integrase genes from the same organisms, using sequences from GenBank and various sequencing projects. We found significant differences between the organismal (16S rRNA) and integrase trees, and we suggest that these differences may be due to HGT.     

Mineralogy and geochemistry of tailings from a gold mine in northeastern Thailand

Mineralogical and geochemical characteristics of tailings from a gold mine in northeastern Thailand were investigated in relation to acid mine drainage (AMD) and the release potentials of toxic elements. The tailings can be divided into upper tailings and lower tailings. The upper tailings usually contain pyrrhotite, pyrite ± chalcopyrite, calcite, quartz, andradite and diopside. The lower tailings mainly contain goethite, quartz, chlorite, muscovite, calcite and hematite ± pyrrhotite. These assemblages clearly relate to the original types of gold deposit prior to mining and mineral processing. The upper tailings are defined as potential acid forming (PAF), whereas the lower tailings are classified as non-acid forming (NAF). Regarding heavy metals, apart from high Mn level, the other heavy metals appear to have low concentrations in the upper tailings. On the other hand, the lower tailings contain high contents of As, Cu and Pb, which appear to be higher than the National Total Threshold Limit Concentrations. Goethite, the main mineral assemblage in the lower tailings, reveals characteristic of arsenic adsorbent. As a result, the tailing pond is recommended to be covered to prevent the oxidizing processes of the upper tailings; otherwise, AMD generation may take place soon after the mine closure. Land reclamation and monitoring plans must be planned very well and carried out with great care since arsenic contamination has been reported in steam water close to the tailing dam.     

Mycorrhizal interactions of orchids colonizing Estonian mine tailings hills

Northeastern Estonia is home to extensive oil shale mines. Associated with these are desolate and environmentally damaging hills of ash and semicoke tailings. Interestingly, some of the first plants to colonize these hills are rare orchids. Here, we assess the identities of the mycorrhizal fungi associated with these orchids, in particular Epipactis atrorubens, Orchis militaris, and Dactylorhiza baltica, and compare them with mycorrhizal fungi from orchids from pristine habitat. Epipactis atrorubens associated with the widest breadth of fungi, including unnamed members of the basidiomycete family Tulasnellaceae and the potentially ectomycorrhizal ascomycetes Trichophaea woolhopeia and Geopora cooperi. Orchis militaris also associated with unnamed members of the Tulasnellaceae. Dactylorhiza baltica associated with Ceratobasidium albasitensis. In Epipactis and Orchis, the same fungi associated with plants in the pristine habitat as with those on ash hills. The tulasnelloid and ceratobasidioid fungi mycorrhizal with these orchids appear closely related to common orchid mycorrhizal fungi, while one of the ascomycetes mycorrhizal with E. atrorubens is closely related to a mycorrhizal fungus with E. microphylla. Our results suggest that these orchids and their fungi are not limited to pristine habitats and that environmentally polluted sites may present novel habitats that may be exploited for endangered plant conservation.     

香蒲对锑矿渣中Sb和As的富集特征

对贵州某锑矿尾矿库进行野外调查、采样,测试该尾矿库矿渣以及生长在渣场内的香蒲(根、茎、叶)中锑与砷的含量。结果表明:渣中锑和砷平均含量分别为3216.49和27.12 mg·kg-1,香蒲根部锑和砷平均含量分别为617.64和19.87 mg·kg-1,叶中锑和砷含量平均值为183.63和0.41 mg·kg-1,茎中锑平均含量为97.63 mg·kg-1。分析表明,香蒲叶中的Sb含量与茎中Sb含量、渣中As含量与渣中Sb含量具有显著相关性,其余各变量之间相关性均不明显。另外,香蒲对矿渣中锑和砷有较强的耐受性,经估算,香蒲对Sb的年转移量为1278 mg·m-2(地上部分为342.71 mg·m-2,地下部分为935.29 mg·m-2);香蒲对As年转移量为31.46 mg·m-2(地上部分为0.75 mg·m-2,地下部分为30.71mg·m-2)。因此,香蒲可作为Sb矿区,特别是尾矿库Sb和As复合污染区生态修复的目标植物之一。     

Natural attenuation potential of cyanide via microbial activity in mine tailings

Biological removal by indigenous microflora of cyanide, contained in old (6-9 years) and fresh tailings (3 months), was studied in order to assess its natural attenuation potential via biodegradation. To investigate the presence of indigenous microflora in tailings, total heterotrophic and cyanide resistant bacteria were counted using the spread-plate method. The free cyanide mineralization potential was estimated using K14CN in the presence of various unlabeled cyanide concentrations (0, 5, and 10 mg CN/kg). The biodegradation of cyanide contained initially in the samples was also investigated by monitoring formate, formamide, ammonia and total cyanide (CNT) concentrations over 111 days. The enumeration of total heterotrophic and cyanide-resistant bacteria in old tailings showed an average population of 105 cfu/g. However, no growth was detected in fresh tailings. Nevertheless, cyanide mineralization tests indicated the presence, in both old and fresh tailings, of a cyanide-degrading microflora. In old tailings, maximum mineralization percentages of free cyanide ranging from 85% to 100% were obtained after 65 days at all concentrations tested. A mineralization percentage of 83% after 170 days was also observed in fresh tailings. No decrease of total cyanide concentration in old tailings was observed when the biodegradation of endogenous cyanide was tested whereas a significant decrease was recorded in fresh tailings after 96 days. The presence of strong metal-cyanide complexes resistant to biodegradation could explain the absence of biodegradation in old tailings. This study demonstrated the presence of an indigenous free cyanide-degrading microflora in both old and fresh tailings, and suggests that natural attenuation of cyanide in gold mine tailings is likely to occur via microbial activity.     

铜陵铜尾矿废弃地生物土壤结皮中的蓝藻多样性

生物土壤结皮是生态系统原生演替过程中的一个早期阶段,在铜陵铜尾矿废弃地自然生态恢复过程中生物土壤结皮在尾矿废弃地表面广泛分布.以生长在铜陵杨山冲和铜官山2处铜尾矿废弃地的生物土壤结皮为研究对象,运用常规培养方法和变性梯度凝胶电泳技术(PCR-DGGE)对不同群落生物土壤结皮中的蓝藻多样性及优势类群进行研究.结果表明2种研究方法所获得的蓝藻种类组成具有明显差异.显微观察结果表明常规培养试验中主要蓝藻类群为微囊藻属(Microcystis)、色球藻属(Chroococcus)、颤藻属(Oscillatoria)、念珠藻属(Nostoc)和浮鞘丝藻属(Planktolyngbya),其中优势种类主要为铜绿微囊藻(Microcystis aeruginosa)、断裂颤藻(Oscillatoria fracta)和细浮鞘丝藻(Planktolyngbya subtilis);提取样品中微生物总DNA,对蓝藻16SrRNA进行PCR-DGGE分析,回收DGGE图谱中24个条带进行测序分析,结果显示,所有序列与GenBank数据库中的近缘蓝藻的相似性系数均在93％以上,其中优势蓝藻类群主要隶属于微鞘藻属(Microcoleus)和细鞘丝藻属(Leptolyngbya),裸地(YL)处和木贼群落下尾矿表面(YM)的生物土壤结皮中优势蓝藻类群主要为微鞘藻属,而黄色真藓-藻类混合结皮(YT)和白茅群落( YB,TG)下的生物土壤结皮中的优势类群主要隶属于细鞘丝藻属.     

Phytostabilization potential of Jatropha curcas L. in polymetallic acid mine tailings

Greenhouse pot experiments were conducted to determine the growth response, metal tolerance, and phytostabilization potential of Jatropha curcas L The plants were grown on different degrees of multi-metal contaminated acid mine soils (T0, control; T1, moderately and T2, highly contaminated soils) with or without limestone amendments. The order of metal accumulation in J. curcas was roots>stems>leaves. The higher tolerance index (>90%) with no phytotoxic symptoms and growth reduction in T1 showed that this plant has the ability to tolerate polymetallic acid mine tailings. Further, various enzymatic and non-enzymatic antioxidants also actively involved in metal defense mechanism in J. curcas. On the other hand, to alleviate the predominant phytoavailable toxic metals such as Al, Cu, and Pb, different rates (0.1, 0.25, 0.50, and 1%) of limestone amendments were added in both T1 and T2 soils. The growth performance of J. curcas was improved due to the increase in soil pH and decrease in phytoavailable soil A1 (95%), Zn (approximately 75%), and Cu (approximately 65%) contents at 0.50% of lime addition. Based on the inherent tolerance ability of J. curcas in existing adverse environmental conditions without liming, it could be used as a suitable candidate for phytostabilization in acid mine tailings.     

Release of metals and arsenic from various mine tailings by Eriophorum angustifolium

Previous investigations have found that plants grown on sulphide-rich mine tailings have phytostabilising effects on acid mine drainage (AMD) by decreasing the pH and preventing the release of metals. The possibility of similar effects on tailings containing other minerals was investigated here. The aim was to examine the effects of Eriophorum angustifolium on four water-covered mine tailings with different mineralogy – i.e. the plants’ effect on the release of elements from the tailings and the uptake of elements – to reveal if E. angustifolium is suitable for phytostabilisation in various tailings. Seeds of E. angustifolium were sown in different tailings amended with sewage sludge. Arsenic, Cd, Cu, Fe, Pb and Zn levels in the drainage water and in plant tissues were examined. pH, alkalinity, and organic acid concentrations were measured in drainage water, and redox potential and O₂ levels in the pore water. The effect of E. angustifolium on the release of metals from the tailings varied with the composition of the tailings. In tailings with a low buffering capacity and low element and sulphide levels, compared with the other tailings, E. angustifolium increased the release of metals, which was shown by the high concentrations of elements and low pH in the drainage water and high concentrations of elements in the shoots, thereby generating a bio-concentration factor (BCF) >1. In tailings with a high concentration of elements, the plants had little effect on the levels of the elements in the drainage water, likely due to the presence of buffering agents in the tailings (added prior to the experiment). In this case, the pH did not decrease in the presence of plants and the shoot BCF was <1.     

五节芒定居对尾矿砂微生物群落结构的影响

根据五节芒(Miscanthus floridulus)定居盖度(0、17%、41%、71%和89%),选择了5个尾矿砂研究样地,并分析了尾矿砂微生物群落结构动态及其与土壤理化特性、重金属含量和植物生物量的关系.结果表明:随着五节芒在尾矿砂上的定居,除pH以外,尾矿砂的有机碳、总氮、总磷、NH4+、-N、NO3--N、速效磷的含量、团聚体稳定性和最大持水量均显著性提高,而土壤重金属总量与DTPA可提取量均显著性下降.主分量分析表明,随着五节芒定居,尾矿砂微生物群落总体结构发生了显著变化,其中革兰氏阳性细菌、革兰氏阴性细菌、真菌、放线菌、菌根菌(16:1ω5c和20:3ω3)、藻类脂肪酸含量以及微生物群落多样性(香农-维纳指数)均显著提高,并且与一些土壤理化特性,如NO3--N、速效磷、团聚体稳定性、土壤全氮和五节芒地上、地下生物量存在着显著或极显著正相关关系.仅有革兰氏阴性细菌和菌根菌脂肪酸含量分别与DTPA-铜呈显著负相关.     

生物结皮对铜尾矿废弃地土壤微生物量及酶活性的影响

生物结皮是铜尾矿废弃地自然原生演替的最初阶段.本研究以铜陵杨山冲铜尾矿库和铜官山新铜尾矿库为对象,采用熏蒸浸提和化学分析法研究了两尾矿库不同类型生物结皮下土壤微生物量C、N及脱氢酶、过氧化氢酶、碱性磷酸酶和脲酶活性.结果表明：铜尾矿废弃地上的生物结皮能够显著提高表层尾矿中的微生物量和土壤酶活性,其中藻类结皮对土壤微生物量C、N的影响高于藓-藻混合结皮,藓类结皮的影响最小;随着土壤生物结皮类型的变化,土壤微生物区系也随之变化;各类生物结皮下表层尾矿中土壤酶活性无显著差异.相关分析表明,碱性磷酸酶活性与土壤微生物量、脱氢酶和脲酶活性呈显著正相关,但与土壤pH呈显著负相关.此外,藓类植物假根能够显著提高藓类结皮假根层的微生物量和酶活性.     

Significance of microbial communities and interactions in safeguarding reactive mine tailings by ecological engineering

Pyritic mine tailings (mineral waste generated by metal mining) pose significant risk to the environment as point sources of acidic, metal-rich effluents (acid mine drainage [AMD]). While the accelerated oxidative dissolution of pyrite and other sulfide minerals in tailings by acidophilic chemolithotrophic prokaryotes has been widely reported, other acidophiles (heterotrophic bacteria that catalyze the dissimilatory reduction of iron and sulfur) can reverse the reactions involved in AMD genesis, and these have been implicated in the "natural attenuation" of mine waters. We have investigated whether by manipulating microbial communities in tailings (inoculating with iron- and sulfur-reducing acidophilic bacteria and phototrophic acidophilic microalgae) it is possible to mitigate the impact of the acid-generating and metal-mobilizing chemolithotrophic prokaryotes that are indigenous to tailing deposits. Sixty tailings mesocosms were set up, using five different microbial inoculation variants, and analyzed at regular intervals for changes in physicochemical and microbiological parameters for up to 1 year. Differences between treatment protocols were most apparent between tailings that had been inoculated with acidophilic algae in addition to aerobic and anaerobic heterotrophic bacteria and those that had been inoculated with only pyrite-oxidizing chemolithotrophs; these differences included higher pH values, lower redox potentials, and smaller concentrations of soluble copper and zinc. The results suggest that empirical ecological engineering of tailing lagoons to promote the growth and activities of iron- and sulfate-reducing bacteria could minimize their risk of AMD production and that the heterotrophic populations could be sustained by facilitating the growth of microalgae to provide continuous inputs of organic carbon.     

自然演替过程中铜尾矿土壤酶活性的变化

铜陵矿区堆放了大量不同时期的铜尾矿,形成大量铜尾矿废弃地,其中的大部分铜尾矿废弃地处于自然生态恢复状态。并形成典型的原生演替系列。为探讨废弃地自然生态恢复中不同演替阶段植物群落变化与土壤酶活性变化的关系,对铜陵3处不同时期弃置的尾矿废弃地进行了调查。随着自然生态系统演替的进行,尾矿中土壤酶活性逐步提高,维管植物群落下尾矿中土壤酶活性〉隐花植物结皮下尾矿中土壤酶活性〉裸地处土壤酶活性;位于植物群落下的尾矿废弃地中脲酶、碱性磷酸酶、过氧化氢酶的活性从表层至下层逐渐降低。不同植物群落对尾矿中土壤酶活性影响有很大差异,位于木贼群落下的尾矿中几种土壤酶的活性高于位于白茅群落和中华结缕草群落下的尾矿中酶的活性。相关分析表明,土壤酶活性与有机质、总N表现出显著的正相关。     

Differential responses of a mine tailings Pseudomonas isolate to cadmium and lead exposures

We examined cadmium and lead resistance in Pseudomonas sp. S8A, an isolate obtained from mine tailings-contaminated soil. Resistant to soluble metal concentrations up to 200 mg l⁻¹ cadmium and 300 mg l⁻¹ lead, S8A produced both exopolymer and biosurfactant. Upon growth, this pseudomonad diverged into two morphologically distinct colony subtypes; small and round or large and flat. In the presence of lead and in the no metal control the large morphotype appeared only in late stationary phase. With cadmium the large morphotype appeared immediately following exposure. Results show that the large morphotype produced greater amounts of surfactant than the small morphotype, suggesting a unique subpopulation response to cadmium toxicity. Results also indicate that an unidentified 28 kDa protein was expressed following exposure to >10 mg l⁻¹ cadmium. This study demonstrates new links between surfactant production, differential subpopulation response and metal exposure.