Polyaspartate, a biodegradable chelant that improves the phytoremediation potential of poplar in a highly metal-contaminated agricultural soil

Role of copper chelating agents: between old applications and new perspectives in neuroscience

The role of copper element has been an increasingly relevant topic in recent years in the fields of human and animal health, for both the study of new drugs and innovative food and feed supplements. This metal plays an important role in the central nervous system, where it is associated with glutamatergic signaling, and it is widely involved in inflammatory processes. Thus, diseases involving copper (II) dyshomeostasis often have neurological symptoms, as exemplified by Alzheimer's and other diseases (such as Parkinson's and Wilson's diseases). Moreover, imbalanced copper ion concentrations have also been associated with diabetes and certain types of cancer, including glioma. In this paper, we propose a comprehensive overview of recent results that show the importance of these metal ions in several pathologies, mainly Alzheimer's disease, through the lens of the development and use of copper chelators as research compounds and potential therapeutics if included in multi-target hybrid drugs. Seeing how copper homeostasis is important for the well-being of animals as well as humans, we shortly describe the state of the art regarding the effects of copper and its chelators in agriculture, livestock rearing, and aquaculture, as ingredients for the formulation of feed supplements as well as to prevent the effects of pollution on animal productions.

Effect of Urea Coated with Polyaspartic Acid on the Yield and Nitrogen Use Efficiency of Sorghum (Sorghum bicolor, (L.) Moench.)

Innovative approaches to enhance N fertilization to improve season-long N availability are essential to optimal sorghum (Sorghum bicolor, (L.) Moench.) productivity and N use efficiency. A two-year field experiment was conducted in the 2020 and 2021 summer seasons on the North China Plain to determine the effects of a novel urea coated with polyaspartic acid (PAA) (PN) and a control treatment (CN) on grain sorghum yield and N utilization characteristics at four N application rates (0, 60, 120, and 240 kg ha⁻¹). The results showed that sorghum yield, agronomic traits (including leaf area duration (LAD), crop growth rate (CGR), and dry matter accumulation (DMA)), the accumulation of nitrate N and ammonium N in the 0–60 cm soil layer, stover and grain N content, and total N uptake (NUT) in 2020 and 2021 significantly increased as N application rates increased from 0 to 240 kg ha⁻¹, whereas nitrogen agronomic efficiency (NAE), N uptake efficiency (NUpE), and N utilization efficiency (NUtE) varied inversely with increasing N application rates. Compared to CN, PN demonstrated a significant enhancement in grain sorghum yield, LAD, and CGR, from 3.3% to 7.1%, from 4.8% to 6.1%, and from 5.8% to 6.8%, respectively, at 60 and 120 kg N ha⁻¹. PN improved the N availability (mainly nitrate-N) in the sorghum soft dough and the stover and grain N content at harvest and NUT, NUpE, and NAE accordingly compared with CN at the 60 and 120 kg ha⁻¹ N application rates. In short, our two-year field trials demonstrated that PN with 120 kg N ha⁻¹ is recommended in grain sorghum to optimize sorghum productivity and nitrogen use efficiency at the current yield level in the North China Plain.

Lead, zinc tolerance mechanism and phytoremediation potential of Alcea rosea (Linn.) Cavan. and Hydrangea macrophylla (Thunb.) Ser. and ethylenediaminetetraacetic acid effect

In this study, we aimed to elucidate the defense mechanism of Alcea rosea (Linn.) Cavan. and Hydrangea macrophylla (Thunb.) Ser. against the single and compound toxicity of lead (Pb) and zinc (Zn) along with the synergistic effect of ethylenediaminetetraacetic acid (EDTA) in accumulation of metals in these two species. The two plant species were subjected to single metal treatment (Pb 1000 mg kg^-1, Zn 600 mg kg^-1) and compound metal treatment (Pb 1000 mg kg^-1 + Zn 600 mg kg^-1) in a greenhouse. Besides, different levels of EDTA were applied (2.5, 5.0, and 10.0 mmol kg^-1) with compound metal treatment. Several physiological and biochemical parameters, including plant photosynthetic parameters, enzymatic antioxidant system, accumulation concentration of metals, and subcellular distribution were estimated. The results showed that the antioxidative enzymes, proline, root morphological changes, and metal localization all played important roles in resisting Pb and Zn toxicity. A notable difference was that Zn was concentrated in the roots (58.5%) of H. macrophylla to reduce the damage but in the leaves (38.5%) of A. rosea to promote photosynthesis and resist the toxicity of metals. In addition, Zn reduced the toxicity of Pb to plants by regulating photosynthesis, Pb absorption and Pb distribution in subcells. The biological concentration factors (BCF) and translocation factors (TF) for Pb in two plants were less than 1, indicating that they could be considered as phytostabilizators in Pb-contaminated soils. Moreover, EDTA could enhance the enrichment and transport capacity of Pb and Zn to promote the phytoremediation effect. In summary, both plants have a certain application potential for repairing Pb-Zn-contaminated soil.

Exploring a library of water-soluble polymers as abiotic phytoremediation agents for treating (Pseudo)metal ion-contaminated soil

Herein, we investigate the effect of eleven water-soluble polymers on the growth of Sedum alfredii and its uptake of As, Cd, or Pb in polluted soil in a pot experiment. The polymers selected are generally non-toxic, metal-chelating, and hygroscopic. They also range from acidic (carboxylate-containing polymers) to neutral (e.g. polyacrylamide, polyvinyl alcohol) and to basic (polyethylene imine). It has been found that sodium alginate exhibits a significant growth-promoting effect (as much as ∼8-fold) as determined by plant total dry weight, while all other tested polymers exert either minor growth promotion or a negative effect. To examine the absorption of heavy (pseudo)metals, the pollutant content in above- and below-ground portions of the plant were separately studied by inductively coupled plasma mass spectrometry. Among the tested polymers, sodium alginate emerges as the strongest absorption accelerator for all three metal pollutants in the above-ground part of the plant (∼3-4-fold increase over blank), mainly due to promotion of plant growth. On the other hand, polyethylene imine is the most potent inhibitor of metal absorption (10%-51% of blank) due to a combination of plant growth inhibition and absorption deactivation. Polymers with such effects may be used to reduce the contamination of (pseudo)metals in crops.

Effects of S,S-ethylenediamine disuccinic acid on the phytoextraction efficiency of Solanum nigrum L. and soil quality in Cd-contaminated alkaline wheat soil

Degradable chelating agent-assisted phytoextraction is a promising method for the remediation of Cd-contaminated agricultural soil. However, there are limited studies that have examined the effect of chelating agents on soil solutions and soil quality in alkaline soil. In this study, the effects of S,S-ethylenediamine disuccinic acid (EDDS) on the growth and phytoextraction of Solanum nigrum L. (S. nigrum) were studied using pot experiments. The influence of EDDS on the soil solutions, heavy metal contents, and soil enzyme activities was evaluated. EDDS application increased the height of S. nigrum by 7.25-29.25 cm and increased the biomass of stem and leaf by 4.26-14.95 and 1.14-10.78 g/pot, respectively. The Cd concentrations in the leaves and berries of S. nigrum were 1.21-2.17 and 1.7-9.47 times higher than that of the control, respectively, and the Cd extraction amount in the shoots of S. nigrum increased by 22.78-256.16 μg/pot after EDDS application. The chelation of EDDS on heavy metals reached a peak after 7 days of application, decreased gradually with the degradation of EDDS, and disappeared after 30 days of application. Soil pH, available metals, metal speciation, and soil urease were significantly related to the application time of EDDS. Importantly, EDDS application 45 days before S. nigrum harvest treatments decreased the available metal concentrations and improved soil pH and urease activity. However, when EDDS was applied 15 days before S. nigrum harvest, the available Cd and Pb concentrations significantly increased and caused additional Pb pollution. Considering the chelation and degradation effects, the environmental implication, and the cost of EDDS, the results of this study showed that one application of EDDS was better than two applications, a 45-day application before harvest was preferred to a 15-day application, and application of 1-3 mM EDDS 30-45 days before S. nigrum harvest was the most promising application method for the remediation of Cd-contaminated alkaline soil.

Combined effects of arbuscular mycorrhizae fungus and composted pig manure on the growth of ryegrass and uptake of Cd and Zn in the soil from an e-waste recycling site

Little attention has been paid to the combined effects of arbuscular mycorrhizae (AM) fungus and composted manure on heavy metal bioavailability and its uptake by plants grown in heavy metal-contaminated soils from electronic-waste (e-waste) recycling sites. A greenhouse pot experiment was conducted to investigate the effects of AM fungus, composted pig manure (CM) and AM fungus + CM (ACM) on the growth of ryegrass and uptake of Cd and Zn in the soil collected from an e-waste recycling site. The calcium chloride (CaCl₂) and Tessier sequential extraction procedure were adopted to evaluate the bioavailability and chemical speciation of Cd and Zn in the soil. Results showed that the application of CM and ACM significantly increased the pH but decreased the CaCl₂-extractable Cd and Zn concentrations in the rhizosphere and bulk soils. ACM treatment significantly shifted Cd from exchangeable fraction to other more stable fractions, and transformed the exchangeable Zn fraction to the carbonate-bound and reducible iron and manganese-bound fractions. Furthermore, the application of ACM can enhance the growth of plant shoots, and decrease the uptake of Cd and Zn in the ryegrass plants. This work suggests that AM fungus in combination with CM amendment may be a potential method for not only remediation of soil Cd and Zn pollution, but also reduction of Cd and Zn uptake by ryegrass grown in the soil from e-waste recycling sites.

Dynamic evolution of humic acids during anaerobic digestion: Exploring an effective auxiliary agent for heavy metal remediation

Information on the dynamic evolution of humic acid (HA) from anaerobic digestate and the potential of HA serving as an effective agent for remedying heavy metals is rather scarce. This study monitored the evolution of the structure and functional groups and metal-binding abilities of HA during chicken manure and corn stover anaerobic digestion (AD) processes. Higher increases in aromatic (41-66%) and oxygen-containing functional groups (37-45%) were observed in HA from the AD of corn stover, resulting in higher metal-binding abilities for Cu(II), Co(II), and Ni(II) than those of chicken manure AD. Moreover, HA extracted from fast (before day 12 for chicken manure and day 16 for corn stover), and slow (day 40) methane production stages performed different complexation capacities for the heavy metals. These results reveal the mechanisms of HA and heavy metal interactions, and confirm the potential of HA extracted from AD process for the remediation of heavy metals.

Aqueous extracts from the selected hyperaccumulators used as soil additives significantly improve accumulation capacity of Solanum nigrum L. for Cd and Pb

The effects of soil treatment with aqueous extracts from three hyperaccumulators on Cd and Pb accumulation by Solanum nigrum L. were determined. The stem (S-RG) and leaf extracts (L-RG) of Rorippaglobosa (Turcz.) Thell., and stem extract (S-BP) of Bidens pilosa L. significantly enhanced Cd and Pb total accumulation capacity of S. nigrum compared to control (by 44 %, 47 %, and 29 % for Cd and by 28 %, 28 % and 21 % for Pb, respectively), while EDTA caused its 9 % and 15 % decrease due to the plant biomass reduction (by 33 %). The leaching experiments reflected affinity of additives to metal mobilization in soils. The concentrations of total organic acid in S-RG, L-RG and S-BP were the highest among studied extracts, which besides the beneficial effect on the soil environment (microbe number and enzyme activities), may be partial reasons of strong promotion of S. nigrum accumulation capacity for Cd and Pb. It was shown that hyperaccumulation properties of a plant are not a prerequisite of enhancing effect of the plant-based soil additive on the metal accumulation capacity of the target living hyperaccumultor. The plant-based chelators were found to be promising candidates for EDTA and other chemicals replacement in promoting efficient and environmentally safe phytoremediation.

Enhanced Phytoextraction for Co-contaminated Soil with Cd and Pb by Ryegrass (Lolium perenne L.)

A pot experiment was conducted to investigate the effect of three additives - citric acid (CA), polyaspartic acid (PASP), and FeCl₃ - on the phytoextraction efficiency of cadmium (Cd) and lead (Pb) by ryegrass (Lolium perenneL.) from artificially contaminated soils with different heavy metal concentrations. The results showed that as the concentration of pollutants increased, the TI (tolerance index) and BCF (bio-concentration factor) of ryegrass gradually increased only when FeCl₃ was applied. FeCl₃ also exhibited the most significant biomass enhancement and heavy metal accumulation of ryegrass, as well as the highest phytoextraction efficiency in heavily-polluted soils. The overall orders of the optimal phytoextraction efficiency for the three additives in terms of their MER (metal extraction ratio) were: FeCl₃ > PASP > CA. Therefore, FeCl₃ can be used to improve the Cd and Pb phytoextraction efficiency of ryegrass in heavily-polluted soils.

Potassium lignosulfonate as a washing agent for remediating lead and copper co-contaminated soils

Lignin is a renewable aromatic polymer which is present in large quantities in the cell walls of terrestrial plants and is the main binding agent for fibrous plant components. Potassium lignosulfonate (KLS), as a by-product of pulping processes, can be applied to agricultural fields as a soil conditioner and chelate fertilizer. In this study, based on its solubility and complexing ability, batch washing and column leaching was explored to evaluate the potential application of KLS in the washing remediation of soil contaminated with lead and copper. Under optimum conditions KLS concentration of 8%, pH of 5.24 and 6 h duration, the removal ratios for the simulated and mining area soils in the batch experiment were 67.40% and 52.87% respectively, for Pb and 73.42% and 55.20% respectively, for Cu. In the column leaching experiment, the removal efficiencies of Pb and Cu increased with solution volume and that the removal ratios of the simulated and mining area soils were 36.46% and 20.31%, respectively, for Pb and 39.74% and 22.76%, respectively, for Cu. KLS can reduce the ratio of acid-soluble and reducible fractions, which may have the most potential hazardous and poisonous for plants. Cation exchange capacity (CEC) and pH of soil were all stable after washing. However, the organic matter and available K, N, and P in the treated soil, which are important factors for plant growth increased significantly. This study showed that KLS can remove Pb and Cu from soil, while improve nutrient (ammonium nitrogen, available phosphorus and available potassium) levels of soil.

EDTA and organic acids assisted phytoextraction of Cd and Zn from a smelter contaminated soil by potherb mustard (Brassica juncea, Coss) and evaluation of its bioindicators

Phytoremediation of contaminated soil is an in-situ reclamation technique for removal of potentially toxic metals through hyperaccumulator plants. Potherb mustard (Brassica juncea, Coss.) is less explored for its assisted phytoextraction potential to restore and accelerate potentially toxic metals removal from smelter-contaminated soil. In this study, different levels of ethylene diamine tetraacetic acid (EDTA) alone and combined with citric acid (CA) and oxalic acid (OA) were applied in a greenhouse pot experiment. Chelates added on 25th d and 25/35th d after sowing, enhanced cadmium (Cd) and zinc (Zn) bioavailability in soil due to complexation. As a result, Cd and Zn in shoot and root were significantly amplified by 1.7, 2.15 and 1.93, 2.7 folds than control, respectively. Shoot and root dry weight significantly reduced and ranged between 4.13-9.91 and 0.21-0.77 g pot^-1, respectively. The toxicity induced by potentially toxic metals in plant imposed a series of biological responses. Plant antioxidants like Phenylalanine ammomialyase (PAL), polyphenol oxidase (PPO) Catalase (CAT) content increased, except the peroxidase (POD) with the addition of chelating agents. Besides, biological concentration factor (BCF) of Cd and Zn, translocation factor (TF) of Cd were notably elevated (>1.0), while TF of Zn was reduced. Pearson correlation analysis showed a positive relation between DTPA-extractable and shoot concentration of Cd and Zn, whereas it showed negative correlation with plant dry weight. In general, chelate-assisted phytoremediation of smelter contaminated soil proved effective in this study, and followed the order: EDTA > EDTA + CA ≈ EDTA + OA > CK.

Effect of soil washing with biodegradable chelators on the toxicity of residual metals and soil biological properties

Soil washing with chelators is a promising and efficient method of remediating metals-contaminated soils. However, the toxicity of residual metals and the effects on soil microbial properties have remained largely unknown after washing. In this study, we employed four biodegradable chelators for removal of metals from contaminated soils: iminodisuccinic acid (ISA), glutamate-N,N-diacetic acid (GLDA), glucomonocarbonic acid (GCA), and polyaspartic acid (PASP). The maximum removal efficiencies for Cd, Pb, and Zn of 85, 55, and 64% and 45, 53, and 32% were achieved from farmland soil and mine soil using biodegradable chelators, respectively. It was found that the capacity of ISA and GLDA to reduce the labile fraction of Cd, Pb, and Zn was similar to that of the conventional non-biodegradable chelator ethylenediaminetetraacetic acid (EDTA). The leachability, mobility, and bioaccessibility of residual metals after washing decreased notably in comparison to the original soils, thus mitigating the estimated environmental and human health risks. Soil β-glucosidase activity, urease activity, acid phosphatase activity, microbial biomass nitrogen, and microbial biomass phosphorus decreased in the treated soils. However, compared with EDTA treatment, soil enzyme activities distinctly increased by 5-94% and overall microbial biomass slightly improved in the remediated soils, which would facilitate reuse of the washed soils. Based on soil toxicity tests that employed wheat seed germination as the endpoint of assessment, the washed soils exhibited only slight effects especially after ISA and GLDA treatments, following high-efficiency metal removal. Hence, ISA and GLDA appear to possess the greatest potential to rehabilitate polluted soils with limited toxicity remaining.

Polyaspartate extraction of cadmium ions from contaminated soil: Evaluation and optimization using central composite design

The occurrences of heavy metal contaminated sites and soils and the need for devising environmentally friendly solutions have become global issues of serious concern. In this study, polyaspartate (a highly biodegradable agent) was synthesized using L-Aspartic acid via a new modified thermal procedure and employed for extraction of cadmium ions (Cd) from contaminated soil. Response surface methodology approach using 3⁵ full faced centered central composite design was employed for modeling, evaluating and optimizing the influence of polyaspartate concentration (36-145mM), polyaspartate/soil ratio (5-25), initial heavy metal concentration (100-500mg/kg), initial pH (3-6) and extraction time (6-24h) on Cd ions extracted into the polyaspartate solution and its residual concentration in the treated soil. The Cd extraction efficacy obtained reached up to 98.8%. Increase in Cd extraction efficiency was associated with increase in the polyaspartate and Cd concentration coupled with lower polyaspertate/soil ratio and initial pH. Under the optimal conditions characterized with minimal utilization of the polyaspartate and high Cd ions removal, the extractible Cd in the polyaspartate solution reached up to 84.4mg/L which yielded 85% Cd extraction efficacy. This study demonstrates the suitability of using polyaspartate as an effective environmentally friendly chelating agent for Cd extraction from contaminated soils.

Reclamation of Cr-contaminated or Cu-contaminated agricultural soils using sunflower and chelants

Chromium (Cr) and copper (Cu) are pollutants with a strong environmental impact. "Green biotechnology" as phytoremediation represents a sustainability opportunity for soil reclamation. In this study, we evaluated the possibility to reclaim agricultural soils located in the Solofrana valley, contaminated by Cr or Cu. Chromium contamination derives by repeated flooding events of Solofrana rivers containing Cr because of leather tanning plants, while Cu soil pollution was due to the use of Cu-rich pesticides in agriculture. Both metals showed a very low bioavailability. In order to perform an assisted phytoremediation of polluted fields, we carried out a preliminary ex situ experimentation testing for the first time sunflowers (cv. Pretor) and chelants (ethylenediaminetetraacetic acid (EDTA) and/or ethylene diamine disuccinate (EDDS)), useful when metal bioavailability is low. No symptoms of toxicity were observed in sunflowers grown on both soils, while biomass was improved when EDDS was added. Cr and Cu bioavailability was only slightly enhanced by chelants at the end of the treatments. Both Cr and Cu were mainly accumulated in the roots; moreover, Cu was also translocated to the aboveground organs in the presence of EDTA. The ex situ experimentation demonstrated that assisted phytoremediation is a very slow process not useful in the case of persistent pollution.

Genetic and biochemical characterization of rhizobacterial strains and their potential use in combination with chelants for assisted phytoremediation

Copper and zinc are essential micronutrients in plants but, at high concentrations, they are toxic. Assisted phytoremediation is an emerging "green" technology that aims to improve the efficiency of tolerant species to remove metals from soils through the use of chelants or microorganisms. Rhizobacteria can promote plant growth and tolerance and also affect the mobility, bioavailability, and complexation of metals. A pot experiment was conducted to evaluate the phytoremediation effectiveness of sunflowers cultivated in a Cu- and Zn-spiked soil, in the presence or absence of bacterial consortium and/or chelants. The consortium was constituted of two Stenotrophomonas maltophilia strains and one of Agrobacterium sp. These strains were previously isolated from the rhizosphere of maize plants cultivated on a metal-polluted soil and here molecularly and biochemically characterized. Results showed that the consortium improved sunflower growth and biomass production on the spiked soils. Sunflowers accumulated large amounts of metals in their roots and leaves; however, neither the bacterial consortium nor the chelants, singularly added to pots, influenced significantly Cu and Zn plant uptake. Furthermore, the consecutive soil amendment with the EDTA and bacterial consortium determined a consistent accumulation of metals in sunflowers, and it might be an alternative strategy to limit the use of EDTA and its associated environmental risks in phytoremediation.

The microbe-secreted isopeptide poly-γ-glutamic acid induces stress tolerance in Brassica napus L. seedlings by activating crosstalk between H2O2 and Ca2

Poly-γ-glutamic acid (γ-PGA) is a microbe-secreted isopeptide that has been shown to promote growth and enhance stress tolerance in crops. However, its site of action and downstream signaling pathways are still unknown. In this study, we investigated γ-PGA-induced tolerance to salt and cold stresses in Brassica napus L. seedlings. Fluorescent labeling of γ-PGA was used to locate the site of its activity in root protoplasts. The relationship between γ-PGA-induced stress tolerance and two signal molecules, H₂O₂ and Ca²⁺, as well as the γ-PGA-elicited signaling pathway at the whole plant level, were explored. Fluorescent labeling showed that γ-PGA did not enter the cytoplasm but instead attached to the surface of root protoplasm. Here, it triggered a burst of H₂O₂ in roots by enhancing the transcription of RbohD and RbohF, and the elicited H₂O₂ further activated an influx of Ca²⁺ into root cells. Ca²⁺ signaling was transmitted via the stem from roots to leaves, where it elicited a fresh burst of H₂O₂, thus promoting plant growth and enhancing stress tolerance. On the basis of these observation, we propose that γ-PGA mediates stress tolerance in Brassica napus seedlings by activating an H₂O₂ burst and subsequent crosstalk between H₂O₂ and Ca²⁺ signaling.

Influence of soil texture on nutrients and potentially hazardous elements in Eremanthus erythropappus

Understanding the factors that control uptake rates and allocation of chemical elements among plant organs is a fundamental prerequisite to improve phytostabilization techniques of hazardous elements in contaminated areas. The present study shows evidence that different substrate textures (coarse and fine laterite) do not significantly change the partitioning of root and shoot dry biomass and with few exceptions, do not significantly affect the final average concentration of elements in Eremanthus erythropappus, but change the root:shoot allocation of both essential nutrients and elements potentially toxic to biota. Growth on coarse laterite resulted in significant higher K (30%), Mg (34%), P (25%), S (32%), Cu (58%), and Na (43%) concentrations in roots and lower Cd concentration (29%). In shoots, coarse laterite led to reduction in K, Fe, Al, and Cr and increase in Na and Sr concentrations. Changes in element allocation could be, in part, a result of differences in the water availability of substrates. Matric potential in coarse laterite was significantly lower in at least 47% of the days analyzed throughout the year. Changes in element phytoextraction or phytostabilization potential could influence the efficiency of rehabilitation projects in areas degraded by mining activities.

The effects of arbuscular mycorrhizal fungi on sex-specific responses to Pb pollution in Populus cathayana

Using fast-growing trees to remediate soils polluted by heavy metals (HMs) has received increasingly more attention, especially for recalcitrant Pb, as one of the most seriously toxic HMs. However, little is known about the responses of plants to a diffused level of Pb pollution, and a more combined phytoremediation technique is needed to explore. In this study, an arbuscular mycorrhizal fungus (AMF), i.e., Funneliformis mosseae, isolated from Populus euphratica distributed in a tailing of Pb/Zn ore, was introduced to investigate its effects on sex-specific responses of P. cathayana in morphology, physiology, and Pb phytoremediation capacity, when exposed to a diffused level of Pb pollution (100mg Pb(2+) kg(-1) dry soil). Symbiosis with exotic AMF did not significantly affect growth of both sexes and biomass allocation. However, when inoculated with AMF, both sexes absorbed more P, but not N in the roots, especially when exposed to the exogenous addition of Pb. The improvement of nutrient status under such conditions might be associated with a further increase in activity of antioxidant enzymes (particularly for superoxide dismutase (SOD) and catalase (CAT)), and the mitigation of oxidation stress induced by excessive reactive oxygen species (ROS). We also observed that exotic AMF could promote the uptake and accumulation of Pb in roots of females, but not in that of males. Therefore, under this diffused pollution level, the infected females might be more suitable for remediation of this metal than infected males, due to the higher capacity of HM accumulation without obvious negative effects on growth and physiological traits. Moreover, field surveys are needed to testify our experimental results, due to diversity of soil microbial community and complexities of their interaction.