Impact of lignin constituents on the bacterial community and polycyclic aromatic hydrocarbon co-metabolism in an agricultural soil.

Lignin is a complex biopolymer comprising phenolic monomers with different degrees of methoxylation and may potentially enhance the degradation of soil pollutants such as polycyclic aromatic hydrocarbons (PAHs) through co-metabolism. However, the contribution of lignin constituents, including phenolic and methoxy subunits, to PAH biodegradation remains unclear. Here, p-hydroxybenzoate (pHBA), vanillate and methanol were selected to simulate phenolic units and methoxy groups of lignin. Soil microcosms receiving these compounds were established to evaluate their regulation on the bacterial community and PAH co-metabolism. There were different effects of different components on the biodegradation of a four-ring PAH, benzo(a)anthracene (BaA), as characterized using an isotopic tracer. Only vanillate significantly stimulated BaA mineralization to CO2, with pHBA and methanol leading to no appreciable change in the allocation of BaA in soil compartments. The lignin constituents had differential impacts on the soil bacterial community, with substantial enrichment of methylotrophs occurring in methanol-supplemented microcosms. Both vanillate and pHBA selected several aromatic degraders. Vanillate caused additional enrichment of methylotrophs, suggesting structure-dependent stimulation of bacterial functional guilds by lignin monomers. Compared with its constituents, lignin produced more extensive responses in terms of bacterial diversity and composition and the fate of BaA. However, it was difficult to link BaA co-metabolism to any specific bacterial taxa in the presence of lignin or its subunits. The results indicate that the co-metabolism effects of lignin may not be directly associated with phenolic or methoxy metabolism but with its regulation of the soil microbiome.

Surfactant-enhanced bioremediation of petroleum-contaminated soil and microbial community response: A field study.

Surfactant-enhanced bioremediation (SEBR) is frequently employed to clean up soil polluted with petroleum hydrocarbons, but few studies have focused on how surfactants affect microbial communities and different fractions of petroleum hydrocarbons, particularly in the field. Here, the surfactants sodium dodecyl benzene sulfonate (SDBS), alpha olefin sulfonate (AOS), Triton X-100 (TX-100), Tween80, and rhamnolipid were combined with the oil-degrading bacterium Pseudomonas sp. SB to remediate oil-contaminated soil in the laboratory. AOS gave the highest removal efficiency (65.1%) of total petroleum hydrocarbons (TPHs). Therefore, AOS was used in a field experiment with Pseudomonas sp. SB and the removal efficiency of TPHs and long-chain hydrocarbons C21-C40 reached 57.4 and 53.0%, respectively, significantly higher than the other treatments. During bioremediation the addition of Pseudomonas sp. SB significantly stimulated the growth of bacterial genera such as Alcanivorax, Luteimonas, Parvibaculum, Stenotrophomonas, and Pseudomonas and AOS further stimulated the growth of Sphingobacterium, Pseudomonas and Alcanivorax. This study validates the feasibility of surfactant-enhanced bioremediation in the field and partly reveals the mechanism of surfactant-enhanced bioremediation from the perspective of changes in different fractions of petroleum and microbial community dynamics.

Zinc uptake and replenishment mechanisms during repeated phytoextraction using Sedum plumbizincicola revealed by stable isotope fractionation.

Improving phytoremediation techniques requires a thorough understanding of the mechanisms of plant uptake and the replenishment of the bioavailable pool of the target element, and this may be effectively explored using stable isotope methods. A repeated phytoextraction experiment over five successive crops of cadmium (Cd) and zinc (Zn) hyperaccumulator Sedum plumbizincicola X.H. Guo et S.B. Zhou ex L.H. Wu (Crassulaceae) was conducted using four agricultural soils differing in soil pH and clay content. The isotopic composition of total Zn and NH4OAc-extractable Zn in soils before phytoextraction and after the fifth crop were determined, together with Zn in shoot samples in the first crop. S. plumbizincicola preferentially took up light Zn isotopes from the NH4OAc-extractable pool (Δ66Znshoot-extract = -0.42 to -0.16‰), indicating the predominance of Zn low-affinity transport. However, after long-term phytoextraction NH4OAc-extractable Zn became isotopically lighter than prior to phytoextraction in three of the soils (Δ66Znextract: P5-P0 = -0.39 to -0.10‰). This was resulted from the equilibrium replenishment of Zn bound to iron (Fe) and manganese (Mn) oxides based on Zn isotopic and chemical speciation analysis. Zinc showed opposite fractionation patterns to Cd in the same plant-soil system with heavy Cd isotope enrichment in S. plumbizincicola (Δ114/110Cdshoot-extract = 0.02-0.17‰) and in the NH4OAc-extractable pool after repeated phytoextraction (Δ114/110Cdextract: P5-P0 = 0.07-0.18‰). This indicates different mechanisms of membrane transport (high-affinity transport of Cd) and supplementation of the bioavailable pool in soil (Cd supplied mainly through complexation with root-derived organic ligands) of the two metals. The combination of chemical speciation and stable Zn isotope ratios in the plant and the bioavailable soil pool reveal that the Zn pool related to Fe and Mn oxides became increasingly bioavailable with increasing crop generations. Capsule: Stable isotope analysis indicates that soil Fe- and Mn-oxide bound Zn replenishment boosted Zn uptake by the hyperaccumulator Sedum plumbizincicola during long-term remediation.

Hydrogen peroxide combined with surfactant leaching and microbial community recovery from oil sludge.

The remediation effects of hydrogen peroxide (H2O2) oxidation and surfactant-leaching alone or in combination on three typical oilfield sludges were studied. The removal efficiency of total petroleum hydrocarbons (TPHs) of Jidong, Liaohe and Jiangsu oil sludges by hydrogen peroxide oxidation alone was very poor (6.5, 6.8, and 3.4 %, respectively) but increased significantly (p < 0.05), especially of long-chain hydrocarbons, by combining the use of H2O2 with surfactants (80.0, 79.8 and 82.2 %, respectively). Oxidation combined with leaching may impair microbial activity and organic manure was therefore added to the treated sludges for biostimulation and the composition and function of the microbial community were studied. The addition of manure rapidly restored sludge microbial activity and significantly increased the relative abundance of some salt-tolerant and alkali-tolerant petroleum-degrading bacteria such as Corynebacterium, Pseudomonas, Dietzia and Jeotgalicoccus. Moreover, the relative abundance of two classic petroleum-degrading enzyme genes, alkane 1-monooxygenase and catechol 1, 2-dioxygenase, increased significantly.

Soil microbial community and association network shift induced by several tall fescue cultivars during the phytoremediation of a petroleum hydrocarbon-contaminated soil.

Biodegradation of soil contaminants may be promoted near plant roots due to the "rhizosphere effect" which may enhance microbial growth and activity. However, the effects of different plant cultivars within a single species on degradation remains unclear. Here, we evaluated the removal of soil total petroleum hydrocarbons (TPHs) by ten different cultivars of tall fescue grass (Festuca arundinacea L.) and their associated rhizosphere microbiomes. TPH removal efficiency across the ten different cultivars was not significantly correlated with plant biomass. Rhizing Star and Greenbrooks cultivars showed the maximum (76.6%) and minimum (62.2%) TPH removal efficiencies, respectively, after 120 days. Significant differences were observed between these two cultivars in the composition of rhizosphere bacterial and fungal communities, especially during the early stages (day 30) of remediation but the differences decreased later (day 90). Putative petroleum-degrading bacterial and fungal guilds were enriched in the presence of tall fescue. Moreover, the complexity of microbial networks declined in treatments with higher TPH removal efficiency. The relative abundances of saprotrophic fungi and putative genes alkB and C12O in bacetria involved in petroleum degradation increased, especially in the presence of Rhizing Star cultivar, and this was consistent with the TPH removal efficiency results. These results indicate the potential of tall fescue grass cultivars and their associated rhizosphere microbiomes to phytoremediate petroleum hydrocarbon-contaminated soils.

Enhanced biomass and cadmium accumulation by three cadmium-tolerant plant species following cold plasma seed treatment.

Cold plasma seed treatment can promote plant growth and enhance the resistance of agricultural crops to adverse stress. However, the effects of plasma seed treatment on the growth and phytoextraction response of plants to cadmium (Cd) remain poorly documented. Here, we have investigated the feasibility of using plasma seed treatment to enhance the biomass and Cd accumulation of three Cd-tolerant species, namely Bidens pilosa L, Solanum nigrum L. and Trifolium repens L, under different plasma treatment conditions. Possible enhancement mechanisms are also proposed according to the levels of organic acids in the roots and the Cd fractions in rhizosphere soil following different plasma treatment conditions. The optimum plasma power was 100 W (B. pilosa) or 500 W (S. nigrum and T. repens). The optimum plasma exposure time for all three species was 60 s. Plasma seed treatment under the optimum treatment conditions enhanced plant dry biomass by ~17.3-45.0% and Cd accumulation by 8.8-54.4% across all three species compared to the controls. Furthermore, the phytoremediation efficiencies, bioaccumulation factors and transfer factors of the three species also increased significantly after seed plasma treatment. The promotion of plasma treatment on the biomass and Cd accumulation of three species might be due to increased exudation of organic acids from the roots into the rhizosphere soil, thus increasing the concentrations of acid-soluble Cd to form Cd-organic acid complexes that facilitated the uptake and translocation of Cd by the plants. Results of this study revealed that cold plasma seed treatment is an environmentally friendly, economical and efficient means to develop the application of phytoremediation for Cd-contaminated soils.

Sustained production of superoxide radicals by manganese oxides under ambient dark conditions.

Manganese (Mn) oxides are ubiquitous in the environment and have strong reactivity to induce the transformation of various contaminants. However, whether reactive oxygen species contribute to their surface reactivity remains unclear. Here, sustainable production of superoxide radicals (O2•-) by various MnO2 polymorphs in the dark was quantified and the mechanisms involved were explored. The results confirm that O2•- was produced through one-electron transfer from surface Mn(III) to adsorbed O2. In contrast, no H2O2 was detected due to its decomposition by Mn oxides to form O2•- and Mn(III), leading to the sustained production of O2•- on Mn oxide surfaces. In addition, the production of O2•- was found to make a clear contribution (4 - 28%) to the transformation of a series of halophenols by MnO2, suggesting that the O2•--mediated surface reaction is an important supplement to the direct electron-transfer mechanism in the reactivity of Mn oxides. These findings advance our understanding of the surface reactivity of Mn oxides and also reveal an important but hitherto unrecognized abiotic source of O2•- in the natural environment.

Enrichment of the soil microbial community in the bioremediation of a petroleum-contaminated soil amended with rice straw or sawdust.

Two common organic wastes from agriculture (rice straw) and forestry (sawdust) were applied to a petroleum-contaminated soil to estimate their effectiveness in the removal of total petroleum hydrocarbons (TPHs) and polycyclic aromatic hydrocarbons (PAHs). Rice straw was the more effective amendment than the other treatments in reducing TPH contents and addition of sawdust resulted in a significant decrease in PAH removal, particularly high-molecular-weight (5-6 ring) PAHs. Principal coordinates analysis (PCoA) indicates that rice straw treatment separated only the bacterial community but sawdust greatly affected both the soil bacterial and fungal communities. Moreover, the abundance of some petroleum degraders such as the bacteria Sphingomonas, Idiomarina and Phenylobacterium and the fungi Humicola, Wallemia and Graphium was promoted by inputs of the two agricultural and forestry wastes. These results highlight the potential of waste applications in accelerating hydrocarbon biodegradation which may be attributed to the enrichment of keystone taxa that show strong positive associations with hydrocarbon degradation.

Temporal Differentiation of Crop Growth as One of the Drivers of Intercropping Yield Advantage.

Intercropping studies usually focus on yield advantage and interspecific interactions but few quantify temporal niche differentiation and its relationship with intercropping yield advantage. A field experiment conducted in northwest China in 2013 and 2014 examined four intercropping systems (oilseed rape/maize, oilseed rape/soybean, potato/maize, and soybean/potato) and the corresponding monocultures. Total dry matter data collected every 20 d after maize emergence were fitted to logistic models to investigate the temporal dynamics of crop growth and interspecific interactions. All four intercropping systems showed significant yield advantages. Temporal niche complementarity between intercropped species was due to differences in sowing and harvesting dates or the time taken to reach maximum daily growth rate or both. Interspecific interactions between intercropped species amplified temporal niche differentiation as indicated by postponement of the time taken to reach maximum daily growth rate of late-maturing crops (i.e. 21 to 41 days in maize associated with oilseed rape or potato). Growth trajectories of intercropped maize or soybean recovered after the oilseed rape harvest to the same values as in their monoculture on a per plant basis. Amplified niche differentiation between crop species depends on the identity of neighboring species whose relative growth rate is crucial in determining the differentiation.

Arbuscular mycorrhizal fungi in soil and roots respond differently to phosphorus inputs in an intensively managed calcareous agricultural soil.

Understanding the diversity and community structure of arbuscular mycorrhizal fungi (AMF) is important for potentially optimizing their role in mining phosphorus (P) in agricultural ecosystems. Here, we conduct a comprehensive study to investigate the vertical distribution of AMF in a calcareous field and their temporal structure in maize-roots with fertilizer P application over a three-year period. The results showed that soil available-P response to P fertilization but maize yields did not. Phosphorus fertilization had no-significant effect on richness of AMF except at greater soil-depths. High P-supply reduced root colonization while optimum-P tended to increase colonization and fungal richness on all sampling occasions. Crop phenology might override P-supply in determining the community composition of active root inhabiting fungi. Significant differences in the community structure of soil AMF were observed between the controls and P treatments in surface soil and the community shift was attributable mainly to available-P, N/P and pH. Vertical distribution was related mainly to soil electrical conductivity and Na content. Our results indicate that the structure of AMF community assemblages is correlated with P fertilization, soil depth and crop phenology. Importantly, phosphorus management must be integrated with other agricultural-practices to ensure the sustainability of agricultural production in salinized soils.

Crop acquisition of phosphorus, iron and zinc from soil in cereal/legume intercropping systems: a critical review.

BACKGROUND: Phosphorus (P), iron (Fe) and zinc (Zn) are essential elements for plant growth and development, but their availability in soil is often limited. Intercropping contributes to increased P, Fe and Zn uptake and thereby increases yield and improves grain nutritional quality and ultimately human health. A better understanding of how intercropping leads to increased plant P, Fe and Zn availability will help to improve P-fertilizer-use efficiency and agronomic Fe and Zn biofortification. SCOPE: This review synthesizes the literature on how intercropping of legumes with cereals increases acquisition of P, Fe and Zn from soil and recapitulates what is known about root-to-shoot nutrient translocation, plant-internal nutrient remobilization and allocation to grains. CONCLUSIONS: Direct interspecific facilitation in intercropping involves below-ground processes in which cereals increase Fe and Zn bioavailability while companion legumes benefit. This has been demonstrated and verified using isotopic nutrient tracing and molecular analysis. The same methodological approaches and field studies should be used to explore direct interspecific P facilitation. Both niche complementarity and interspecific facilitation contribute to increased P acquisition in intercropping. Niche complementarity may also contribute to increased Fe and Zn acquisition, an aspect poorly understood. Interspecific mobilization and uptake facilitation of sparingly soluble P, Fe and Zn from soil, however, are not the only determinants of the concentrations of P, Fe and Zn in grains. Grain yield and nutrient translocation from roots to shoots further influence the concentrations of these nutrients in grains.

Enhancement of faba bean competitive ability by arbuscular mycorrhizal fungi is highly correlated with dynamic nutrient acquisition by competing wheat.

The mechanistic understanding of the dynamic processes linking nutrient acquisition and biomass production of competing individuals can be instructive in optimizing intercropping systems. Here, we examine the effect of inoculation with Funneliformis mosseae on competitive dynamics between wheat and faba bean. Wheat is less responsive to mycorrhizal inoculation. Both inoculated and uninoculated wheat attained the maximum instantaneous N and P capture approximately five days before it attained the maximum instantaneous biomass production, indicating that wheat detected the competitor and responded physiologically to resource limitation prior to the biomass response. By contrast, the instantaneous N and P capture by uninoculated faba bean remained low throughout the growth period, and plant growth was not significantly affected by competing wheat. However, inoculation substantially enhanced biomass production and N and P acquisition of faba bean. The exudation of citrate and malate acids and acid phosphatase activity were greater in mycorrhizal than in uninoculated faba bean, and rhizosphere pH tended to decrease. We conclude that under N and P limiting conditions, temporal separation of N and P acquisition by competing plant species and enhancement of complementary resource use in the presence of AMF might be attributable to the competitive co-existence of faba bean and wheat.

Isolation, identification and characterization of Bacillus amyloliquefaciens BZ-6, a bacterial isolate for enhancing oil recovery from oily sludge.

Over 100 biosurfactant-producing microorganisms were isolated from oily sludge and petroleum-contaminated soil from Shengli oil field in north China. Sixteen of the bacterial isolates produced biosurfactants and reduced the surface tension of the growth medium from 71 to <30 mN m(-1) after 72 h of growth. These bacteria were used to treat oily sludge and the recovery efficiencies of oil from oily sludge were determined. The oil recovery efficiencies of different isolates ranged from 39% to 88%. Bacterial isolate BZ-6 was found to be the most efficient strain and the three phases (oil, water and sediment) were separated automatically after the sludge was treated with the culture medium of BZ-6. Based on morphological, physiological characteristics and molecular identification, isolate BZ-6 was identified as Bacillus amyloliquefaciens. The biosurfactant produced by isolate BZ-6 was purified and analyzed by high performance liquid chromatography-electrospray ionization tandem mass spectrometry. There were four ion peaks representing four different fengycin A homologues.

Prepared bed bioremediation of oily sludge in an oilfield in northern China.

Field-scale bioremediation of oily sludge in prepared beds was studied at Shengli oilfield in northern China. The influence of manure, coarse sand, sawdust, a specialized microbial preparation and greenhouse conditions on the efficiency of removal of oil and grease was evaluated. After bioremediation for 230d, oil and grease content fell by 32-42gkg(-1)dry sludge in treated plots, indicating removal of 27-46% compared with only 15% in the control plot. Addition of manure, coarse sand, sawdust and greenhouse conditions significantly (p<0.05) increased the amount removed. Moreover, the physico-chemical properties of the sludge in all treated plots improved significantly after bioremediation. Microbial biomass in sludge and community-level physiological profiling examined using BIOLOG microplates was also studied. Total petroleum hydrocarbon degraders and polycyclic aromatic hydrocarbon degraders increased in all treated oily sludge. The activity of sludge microbial communities increased markedly in the treated plots compared with the control. Canonical correspondence analysis showed that differences in substrate utilization patterns were highly correlated (p<0.05) with sludge hydrolyzable N and oil and grease content. The biological toxicity of the oily sludge was lower following bioremediation in most of the treated plots as evaluated using Photobacterium phosphoreum T3.

The arbuscular mycorrhizal fungus Glomus mosseae can enhance arsenic tolerance in Medicago truncatula by increasing plant phosphorus status and restricting arsenate uptake.

A pot experiment examined the biomass and As uptake of Medicago truncatula colonized by the arbuscular mycorrhizal (AM) fungus Glomus mosseae in low-P soil experimentally contaminated with different levels of arsenate. The biomass of G. mosseae external mycelium was unaffected by the highest addition level of As studied (200 mg kg(-1)) but shoot and root biomass declined in both mycorrhizal and non-mycorrhizal plants, indicating that the AM fungus was more tolerant than M. truncatula to arsenate. Mycorrhizal inoculation increased shoot and root dry weights by enhancing host plant P nutrition and lowering shoot and root As concentrations compared with uninoculated plants. The AM fungus may have been highly tolerant to As and conferred enhanced tolerance to arsenate on the host plant by enhancing P nutrition and restricting root As uptake.

Improved approaches for modeling the sorption of phenanthrene by a range of plant species.

Equilibrium sorption of phenanthrene and its relationship with plant lipid contents were investigated using roots and shoots of alfalfa, ryegrass, tomato, potato, carrot, cucumber, zucchini, and pumpkin. Lipid extractions using chloroform and hexane were compared, and the influence of dechlorophyllization on lipid determinations was evaluated. The sorption isotherms were close to linear (R2 > 0.923, P < 0.05) and the plant-water partition coefficients (K(pl)) of phenanthrene obtained from the isotherms exhibited significant and positive correlations with plantlipid contents (R2 > 0.664, P < 0.05). The correlations were more significant (R2 > 0.906, P < 0.001) when dechlorophyllization was included in the lipid extraction. The measured sorption was higher than that estimated using the octanol-water partition coefficient (K(ow)) but was very close to the estimate using the triolein-water partition coefficient (K(tw)). This study leads us to conclude that dechlorophyllization is necessary for plant lipid determination and that K(tw) is more accurate as a substitute for the lipid-water partition coefficient (K(lip)) than K(ow). These novel approaches may provide substantial improvements in the application of partition-limited models for the estimation of plant uptake of organic contaminants.

Arsenic uptake by arbuscular mycorrhizal maize (Zea mays L.) grown in an arsenic-contaminated soil with added phosphorus.

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment. Non-mycorrhizal and zero-P addition controls were included. Plant biomass and concentrations and uptake of As, P, and other nutrients, AM colonization, root lengths, and hyphal length densities were determined. The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium. Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments, but shoot and root biomass of AM plants was depressed by P application. AM fungal inoculation decreased shoot As concentrations when no P was added, and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition, respectively. Shoot and root uptake of P, Mn, Cu, and Zn increased, but shoot Fe uptake decreased by 44.6%, with inoculation, when P was added. P addition reduced shoot P, Fe, Mn, Cu, and Zn uptake of AM plants, but increased root Fe and Mn uptake of the nonmycorrhizal ones. AM colonization therefore appeared to enhance plant tolerance to As in low P soil, and have some potential for the phytostabilization of As-contaminated soil, however, P application may introduce additional environmental risk by increasing soil As mobility.

The Scottish approach to enhancing antimicrobial stewardship.

In 2002, the Scottish Executive produced the Antimicrobial Resistance Strategy and Scottish Action Plan, which highlighted antimicrobial stewardship as a key objective in combating resistance. An important response, as a part of the Ministerial Healthcare Associated Infection Task Force work programme was the publication of 'Antimicrobial Prescribing Policy and Practice in Scotland: recommendations for good antimicrobial practice in acute hospitals' in 2005. This article briefly reviews the core components of the Scottish approach, reviews progress with some key goals and explores how many of these goals are being taken forward through a cohesive Scottish national multifaceted strategy, which incorporates primary and secondary care. Much of this will spring from the current review of the Scottish Action Plan. While recognizing the significant progress achieved by the Appropriate Antimicrobial Prescribing for Tomorrow's Doctors Project Group in the education of undergraduate medical students, the article also reviews the NHS Education Scotland-supported Scottish National Antimicrobial Prescribing Project, aimed at foundation training doctors in Scotland. We hope that this experience can be shared and further developed with colleagues within the United Kingdom and European Union.

Uptake of zinc, cadmium and phosphorus by arbuscular mycorrhizal maize (Zea mays L.) from a low available phosphorus calcareous soil spiked with zinc and cadmium.

In a multifactorial pot experiment, maize (Zea mays L.) with or without inoculation with the arbuscular mycorrhizal (AM) fungus Glomus mosseae BEG167 was grown in a sterilized soil spiked with three levels of zinc (0, 300 and 900 mg Zn kg(-1) soil) and three levels of cadmium (0, 25 and 100 mg Cd kg(-1) soil). At harvest after 8 weeks of growth, the proportion of root length of inoculated plants colonized decreased with increasing Zn or Cd addition, and was 56% in the absence of both metals and was reduced significantly to 27% in the presence of the higher levels of both metals. Mycorrhizal plants had higher biomass than non-mycorrhizal controls except at the highest soil level of Cd. Cadmium had more pronounced effects on plant biomass than did Zn at the levels studied and the two metals showed a significant interaction. The data suggest that mycorrhizal inoculation increased plant growth with enhancement of P nutrition, perhaps increasing plant tolerance to Zn and Cd by a dilution effect. AM inoculation also led to higher soil solution pH after harvest, possibly reducing the availability of the metals for plant uptake, and lowered the concentrations of soluble Zn and Cd in the soil solution, perhaps by adsorption onto the extrametrical mycelium.

Metal concentrations and mycorrhizal status of plants colonizing copper mine tailings: potential for revegetation.

A field survey of metal concentrations and mycorrhizal status of plants growing on copper mine tailings was conducted in Anhui Province, China. Available phosphorus and organic matter in the tailings were very low. High concentrations of Pb, Zn, As and Cd as well as Cu were observed on some sites. The dominant plants growing on mine tailings belonged to the families Gramineae and Compositae, and the most widely distributed plant species were Imperata cylindrica, Cynodon dactylon and Paspalum distichum. Coreopsis drummondii also grew well on the arid sites but not on wet sites. Very low or zero arbuscular mycorrhizal (AM) fungal colonization was observed in most of the plants, but extensive mycorrhizal colonization was recorded in the roots of C. drummondii and C. dactylon. Metal concentrations in plant tissues indicated that I. cylindrica and P. distichum utilized avoidance mechanisms to survive at high metal concentrations. The investigation suggests that remediation and revegetation of heavy metal contaminated sites might be facilitated by selection of tolerant plant species. Isolation of tolerant AM fungi may also be warranted.