Influence of lead,cadmium, and nickel on the growth ofMedicago sativa (L.)

Summary Alfalfa (Medicago sativa L.), cv. Iroquois, was grown in the greenhouse in soils amended with additions of either lead, cadmium, or nickel. Metals, at rates varying from 0–250 ppm, were not uniformly mixed but were placed close to the soil surface so as to simulate surface deposition. In one series of experiments the sulphate salt of each metal and two soils were used. In a second series of experiments the nitrate salts and one soil were used. Neither salt of lead significantly depressed alfalfa yields. Both salts of either cadmium or nickel significantly depressed yields. Additions of all metals to the soil resulted in both increased metal uptake and concentrations in alfalfa tissue, particularly for cadmium and nickel. The highest tissue concentrations of cadmium and nickel were associated with plant stunting and necrosis. However, at rates of 125 ppm and less, substantial increases in cadmium and nickel concentrations were obtained frequently without serious yield reductions. Generally, metal concentrations were greatest in the first harvest following metal application. Concentration and uptake of lead and cadmium were greater when the metal was applied to the soil as nitrate than when applied as the sulphate salt.     

Uptake of six heavy metals by oat as influenced by soil type and additions of cadmium,lead, zinc and copper

Summary The influence of heavy metal additions on availability and uptake of cadmium, lead, zinc, copper, manganese and iron by oat was studied. The experiments were carried out as pot experiments using sandy loam, sandy soil and organic soil. Selective extractants were used to remove metals held in different soil fractions.Lead and copper were preferently bound by organics and oxides, zinc by oxides and inorganics, and cadmium by inorganics and organics.Addition of cadmium to the soils resulted in higher cadmium concentrations in all plant parts but lower concentrations of lead, zinc, copper, manganese and iron, and the accumulation indexes of these metals were also lower when cadmium was added to the soil.Addition of cadmium plus lead, zinc and copper resulted in higher cadmium concentrations in leaves and straw of plants grown in sandy loam and sandy soil, but lower concentrations when plants were grown in organic soil as compared with the results when cadmium was added separately. The transfer of cadmium, lead, zinc and copper from soil to plant was greatest from sandy soil, and zinc and cadmium were more mobile in the plant than were lead and copper.Cadmium concentrations in leaves correlated significantly with CaCl₂ and CH₃COOH extractions in sandy loam and sandy soil and with CH₃COOH extractions in organic soil.Generally, the total metal uptake was lowest from organic soil.     

Influence of iron and pH on the yield and iron,manganese, zinc,and sulfur concentrations of carrots grown on sphagnum peat soil

Summary In two greenhouse experiments, sphagnum peat, adjusted to various pH levels, was used to study the effect of various levels of Fe on the growth of carrots (Daucus carota L., var. sativa D.C.). The Fe was added to the medium as sequesterine 330 chelate. Maximum carrot root and top tissue yields were obtained at soil pH 6.6 and 7.1. At soil pH 5.2 and 7.8 the yields were in the intermediate range. The yields were low at pH 4.3, 4.5 and 8.1 and at pH 8.4 the carrots did not grow. The chlorotic symptoms on carrot leaves, accom-panied by reduced yields, were associated with 39 to 82 ppm Fe and > 332 ppm Mn in the leaf and were likely due to Mn toxicity. Toxic levels of Mn in tissue were found even at soil pH 8.1 and were associated with reduced carrot yields. The leaf tissue concentrations of Fe and Mn decreased as the pH of soil increased; however, at pH 5.2, 7.8, and 8.1 the tissue Mn concentration increased. The added Fe had no effect on the Fe concentration but decreased the Mn and Zn concentration of leaf tissue and increased carrot root yields. There was a significant interaction between added lime and Fe, whereby the decrease in leaf tissue Mn concentration and increases in root yields with added Fe were much greater at pH 4.5 and 5.2 than at pH values of 6.6 and 7.8. The S concentration in the leaf tissue decreased with added Fe and lime. The leaf tissue Zn concentrations of 184 to 490 ppm and S concentrations of 0.32 to 0.63%, as found here, are considered to be high but not in the toxic range.Contribution No. 321, Research Station, Charlottetown, P.E.I. and No. 1534, Research Station, Kentville, N.S.Contribution No. 321, Research Station, Charlottetown, P.E.I. and No. 1534, Research Station, Kentville, N.S.     

Phytoextraction of Metals and Rhizoremediation of PAHs in Co-Contaminated Soil by Co-Planting of Sedum Alfredii with Ryegrass (Lolium Perenne) or Castor (Ricinus Communis)

A pot experiment was conducted to investigate the potential for phytoextraction of heavy metals and rhizoremediation of polycyclic aromatic hydrocarbons (PAHs) in co-contaminated soil by co-planting a cadmium/zinc (Cd/Zn) hyperaccumulator and lead (Pb) accumulator Sedum alfredii with ryegrass (Lolium perenne) or castor (Ricinus communis). Co-planting with castor decreased the shoot biomass of S. alfredii as compared to that in monoculture. Cadmium concentration in S. alfredii shoot significantly decreased when grown with ryegrass or castor as compared to that in monoculture. However, no reduction of Zn or Pb concentration in S. alfredii shoot was detected in co-planting treatments. Total removal of either Cd, Zn, or Pb by plants was similar across S. alfredii monoculture or co-planting with ryegrass or castor, except enhanced Pb removal in S. alfredii and ryegrass co-planting treatment. Co-planting of S. alfredii with ryegrass or castor significantly enhanced the pyrene and anthracene dissipation as compared to that in the bare soil or S. alfredii monoculture. This appears to be due to the increased soil microbial population and activities in both co-planting treatments. Co-planting of S. alfredii with ryegrass or castor provides a promising strategy to mitigate both metal and PAH contaminants from co-contaminated soils.     

Control of stem nematode, Ditylenchus dipsaci Coat race'), by aldicarb and resistant crop plants

Aldicarb at 1.5 or 4.5 kg ha^-1 applied around the seeds at sowing greatly increased the yields of a range of crop plants in soil heavily infested with stem nematode (Ditylenchus dipsaci, ‘oat race’). Yield responses could be largely explained by stem nematode control in onions, field beans, peas, Manod oats and maize but not in wheat, Maris Tabard oats, lucerne or sugar beet. Aldicarb lessened stem nematode attacks and lessened stem nematode increase in host plants. The supposedly resistant oat Manod was susceptible, whereas Maris Tabard was resistant, as were Peniarth, Pennal, Panema, Pennant, Maris Quest and Milford, whose resistances derive from Grey Winter. Maris Tabard outyielded resistant Panema, Peniarth and Pennal and susceptible Maris Osprey and Manod on infested soil. ‘Tulip root’ is not an infallible guide to susceptibility of oats to stem nematode. We advocate using a mixture of nematode populations in breeding for resistance to stem nematodes.     

Heavy-metal ion uptake by plants from nutrient solutions with metal ion,plant species and growth period variations

Summary Rape, cucumber, wheat, oats and tomato were grown for one to two weeks in nutrient solutions with heavy metals added. Of the metal ions tested (Cr³⁺, Cu²⁺, Co²⁺, CrO₄ ^2-, Ni²⁺, Cd²⁺, Pb²⁺, Mn²⁺, Zn²⁺ and Ag⁺), manganese, nickel and lead exhibited the greatest mobility in cucumber plants, which resulted in the highest shoot/root concentration ratio. Silver was not translocated to the shoots of cucumber plants in measurable amounts.When the plants were grown with 1.0, 10 and 100 M cadmium or nickel in the solution, the shoot and root concentration increased 5–10 times if the metal ion concentration of the solution was increased 10 times.The plants showed great differences in cadmium and nickel uptake. In the shoot, the cadmium concentration increased in the order: oats = wheat < cucumber = rape < tomato, and in the root in the order: oats = wheat < cucumber = rape < tomato. The great uptake of cadmium and nickel by tomato is notable and agrees with other reports.The nickel, and especially the cadmium, concentration in roots and shoots increases with the age of the plant.The results are discussed and related to other investigations. The need for research on the uptake mechanisms of non-essential heavy metals is emphasized. re]19750415     

Role of mycorrhizal infection in the growth and reproduction of wild vs. cultivated plants

Summary We tested the hypothesis that mycorrhizal infection benefits wild plants to a lesser extent than cultivated plants. This hypothesis stems from two observations: (1) mycorrhizal infection improves plant growth primarily by increasing nutrient uptake, and (2) wild plants often possess special adaptations to soil infertility which are less pronounced in modern cultivated plants. In the first experiment, wild (Avena fatua L.) and cultivated (A. sativa L.) oats were grown hydroponically at four different phosphorus levels. Wild oat was less responsive (in shoot dry weight) to increasing phosphorus availability than cultivated oat. In addition, the root: shoot ratio was much more plastic in wild oat (varying from 0.90 in the low phosphorus solution to 0.25 in the high phosphorus solution) than in cultivated oat (varying from 0.44 to 0.17). In the second experiment, mycorrhizal and non-mycorrhizal wild and cultivated oats were grown in a phosphorus-deficient soil. Mycorrhizal infection generally improved the vegetative growth of both wild and cultivated oats. However, infection significantly increased plant lifespan, number of panicles per plant, shoot phosphorus concentration, shoot phosphorus content, duration of flowering, and the mean weight of individual seeds in cultivated oat, while it had a significantly reduced effect, no effect, or a negative effect on these characters for wild oat. Poor positive responsiveness of wild oat in these characters was thus associated with what might be considered to be inherent adaptations to nutrient deficiency: high root: shoot ratio and inherently low growth rate. Infection also increased seed phosphorus content and reproductive allocation.     

Aspects in oat breeding: nutrition quality,nakedness and disease resistance,challenges and perspectives

Traditionally, the oat crop (Avena sativa) has been neglected in a number of respects, cultivated in cropping areas not optimal for wheat, barley or maize. In recent years the interest in oats has increased, particularly because of its dietary benefits and therapeutic potential for human health. The uniqueness and advantages of naked oats over other popular cereals, due to its potentially valuable nutritional composition, have been well studied and reported, opening new market “niches” for oats. Despite the well‐documented benefits, the status of the oat crop is still fragile, due to many reasons. The area cultivated for the oat crop is much less compared with other cereals, and therefore commercial efforts in oat breeding are less. Oat groat yield is lower than other cereals such as wheat and the nutritious uniqueness has not been reflected in agreeable market prices. The same price still exists for both naked and conventional/covered oats in the world grain market. The absence of visible market competitiveness, and some of the oat biological drawbacks, including low grain yield, keeps the oat crop as a lower profitability minor crop. This review is intended to analyse and summarise main achievements and challenges in oat genetics, agronomy and phytopathology to find possible ways of oat improvement and future perspectives for oat breeding.     

Remediation of lead and cadmium-contaminated soils

The research was designated to study the ability of plants to bio-accumulate, translocate and remove the heavy metals, lead and cadmium from contaminated soil. The herbal plant ryegrass, Lolium multiflorum was investigated as a bio-accumulator plant for these metals. The translocation of these heavy metals in the herbal plant was compared considering root to shoot transport and redistribution of metals in the root and shoot system. The trace metal contents from root and shoot parts were determined using atomic absorption spectrometer. The results showed that the percent of lead and cadmium transferred to ryegrass plant were averaged as 51.39, and 74.57%, respectively, while those remained in the soil were averaged as 48.61 and 25.43% following 60 days of treatment. The soil-plant transfer index in root and shoot system of ryegrass was found to be 0.32 and 0.20 for lead, and 0.50 and 0.25 for cadmium. These findings indicated that the herbal plant ryegrass, Lolium multiflorum is a good accumulator for cadmium than lead. The soil-plant transfer factor (the conc. of heavy metal in plant to the conc. in soil) indicated that the mechanism of soil remedy using the investigated plant is phytoextraction where the amounts of heavy metals transferred by plant roots into the above ground portions were higher than that remained in the soil. The method offers green technology solution for the contamination problem since it is effective technology with minimal impact on the environment and can be easily used for soil remedy.     

土壤中镉、铅、锌及其相互作用对作物的影响

通过作物盆栽模拟试验(砂壤质褐土、pH值8.2)揭示：土壤中分别施入镉(CdCl2)、铅[Pb(CH3COO)2]或锌(ZnSO4)其影响表现为,植物各器官镉的含量超过对照植物的数倍至500倍。土壤镉浓度<5ppm和<10ppm分别造成某些蔬菜和水稻的污染。铅主要积累在植物根部,土壤铅污染对作物的影响较小。锌主要积累在植物叶片和根部,对水稻产生生长抑制的土壤锌浓度临界值不大于200ppm,此浓度对旱作无影响。土壤中同时施入镉和铅,植物对镉的吸收增加。而土壤中镉的增加却减少了植物体内铅的含量。土壤中由于镉、锌或铅、锌相互作用的结果,水稻对它们的吸收都有增加。在旱地土壤锌浓度的增高,降低了植物对镉、铅的吸收。镉、铅、锌同时施入土壤由于相互作用的结果,除锌之外,植物对镉、铅的吸收有明显下降。评价土壤重金属污染,不仅要看它们的含量及其存在形态,而且要分析它们之间的相互作用(促进或拮抗)特点。     

Manganese-phosphate reactions in aqueous systems and the effects of applications of monocalcium phosphate,on the availability of manganese to oats in an alkaline fen soil

Summary Electrometric titrations and chemical analyses of aqueous systems containing manganese sulphate and phosphoric acid showed that the compositions of manganese phosphates formed at various pH values depended on initial manganese concentrations and Mn : P molar ratios. The results show how phosphate benefits crops on soils containing toxic levesl of manganese.A pot experiment measured the effects of monocalcium phosphate, in the presence or absence of extra manganese, on the availability to oats of manganese in an alkaline manganese-deficient soil. On such a soil, phosphate equivalent to 750 or 1500 pounds of superphosphate per acre is unlikely to enhance manganese availability; such dressings may lessen grain yields considerably.Neutral and alkaline manganese-deficient fen soils were incubated with monocalcium-phosphate with and without added manganese salts. The phosphate dressings had only small effects on soil pH and on exchangeable and readily reducible manganese.     

Effect of incorporated green manure crops on subsequent oat production in an acid,infertile silt loam

A field-size experiment was initiated in 1982 on an acid, low fertility Springhill silt loam to determine the effect of five unfertilized green manure crops (alsike clover, sweet clover, single- and double-cut red clover, and buckwheat) on subsequent oat production and soil fertility. The field was limed in 1982 and green manures were seeded (without fertilizer) in spring, 1983 in 1400 m² strips randomly assigned within three treatment blocks. Plant tissue samples were taken from different locations in each plot in the fall of 1983 and all crops were incorporated. In 1984 the field was separated into an upper and lower section and each section received three rates of NPK fertilizer (0; 30-36-36; 60-72-72 kg ha^-1) spread across the previous strips. Gary oats were seeded and at harvest were divided into grain and straw. The results indicated significant effects of field sample location, green manure type and fertilizer level on oat yields. Buckwheat significantly reduced oat production compared to the four clovers, while the highest fertilizer rate improved oat yields compared with the other levels of fertilizers. Elemental analysis of the green manure crops and soil fertility was compared with data of the same crops grown in more fertile, neutral soils.     

Effect of heavy metals on isoperoxidases of Wheat

The influence of increasing concentrations of copper, zinc, lead, nickel, chromium and cadmium on 14-day-old seedlings of wheat (Triticum aestivum L. cv. Vergina) was studied. Plants were grown in 1/10 strength Rorison’s nutrient solution with increasing concentrations of each of the metals added separately. The toxicity of metals depressed shoot growth but the most evident symptoms were on roots. The concentration of each metal which caused inhibition of root growth was chosen to study the influence of metals on isoperoxidases of wheat shoots. The concentrations employed did not alter the number of peroxidase bands but almost in all cases enhanced the intensities of bands of pH 4.0-4.2 and 5.0-5.4, while they decreased the intensities of bands of pH 4.2-4.6 and 5.4-6.5. The similar effects of the different heavy metals employed may suggest similarity in metal action on wheat isoperoxidases. The increased intensities of peroxidase bands may be considered as an indication of enhanced senescence caused by the heavy metal treatments. Generally, our results suggest that the heavy metals employed have caused complex changes on the multiple forms of peroxidases.     

An “ex situ” microbial process for the removal of heavy metals from polluted soil: A case study of Ada rice field,Adani, Enugu State,Nigeria

An “ex situ” microbial method for the removal of heavy metals from soil is described. Elemental sulfur was added to generate the lixiviant in shaker flask experiments in which soil sampled from a polluted agricultural field was treated. The biotic oxidation of sulfur to sulfuric acid resulted in significant drop in pH of the bioleaching liquor from 6.94 to 1.8 after 50 days. In batches operated at very low (10 g/kg) sulfur concentrations, pH changed from 6.94 to 5.45. The 50 g/kg soil sulfur concentration was found to be most beneficial to the solubilization process because more than 95% of metals such as zinc (Zn), cadmium (Cd), and nickel (Ni) were recovered while approximately 67% of manganese (Mn) got solubilized. The least concentration of dissolved metals was lead (Pb) – (25%) and chromium (Cr) – (10%). Sulfate accumulation rose to 47% in samples spiked with 50 g/kg soil of sulfur. At lower sulfur concentrations, the sulfates generated were higher than the amount of sulfur added. The microbial process compared well to the abiotic process involving extraneous addition of sulfuric acid except that very high concentrations of acid had to be used. The treatment of the bioleaching wastewater promoted precipitation of the dissolved metals into insoluble hydroxides making discharge of the effluent into the environment safe. The leached soil recovered sufficiently for agricultural use after quick lime and animal manure was used to improve, stabilize, and restore its physical, chemical, and biological conditions.     

Investigation of Metal levels in Artemisia herba-alba Medicinal Plant and Soil Samples Collected from Different Areas in Jordan Country

ABSTRACT

The concentrations of selected heavy metals including cadmium (Cd), lead (Pb), zinc (Zn), copper (Cu), nickel (Ni) and iron (Fe) in stems and leaves of Artemisia herba-alba medicinal plant and soil samples were evaluated. Results showed that there in heavy metal concentrations of washed and unwashed parts of A. herba-alba from northern site (Irbid), Middle site (Al-Mafraq), and Souhern site (Ma’an) (P < .05). Moreover, the results of this study revealed that there is a correlation between heavy metal levels in medicinal plants and their concentrations in soil. Two standard reference materials of plant (SRM 1790a; spinach, CRM 281; ryegrass) and a standard reference material of soil (GBW 07406) were examined to validate the method used. There were good agreements between the measured values of these standard reference materials and their certified values. In addition to that high recoveries for tested elements were ranged between 91.7–97.7%, 90–96.6%, and 92.2–97.7% in (CRM281, ryegrass), (SRM1570a, spinach) and (GBW 04706, soil) respectively. It is reasonable to conclude that the variation in metal concentration from site to another site as well as from element to another element may be due to the different factors such as traf?c volumes, the wind directions, the soil nature, and the element behavior.

Based on the results obtained, the health authorities will take in consideration these useful information and direct the residents about the risk of these pollutants.     

Speciation analysis of nickel in soil solutions and availability to oat plants

Soil solutions were collected for speciation analysis of nickel from a pot experiment with oats. Oat plants (Avena sativa L.) were grown on 3 soils differing in total amount and origin of nickel (Ni) (Luvisol, LS with 28 mg kg^-1; sludge amended Luvisol, LS+SS with 32 mg kg^-1; Cambisol, CS with 95 mg kg^-1). Results were compared with those for soil solutions obtained from corresponding unplanted pots. Separation methods were used for characterization of size and charge distribution and stability of the Ni species. In addition, short-term experiments were performed on the uptake rates of Ni by oat plants from the different soil solutions as well as from nutrient solutions with increasing concentrations of a synthetic chelator.The Ni concentrations in the soil solutions of unplanted soils increased in the order: LS5000 g mol^-1) was the predominant form, whereas in the other soils the low-molecular-size cationic and chelated Ni species (500–1000 g mol^-1) dominated in the soil solution. In the short-term uptake studies, the uptake rates of Ni from the solutions decreased in the order: nutrient solution > soil solutions, and in the latter in the order: LS>LS+SS>CS, which was inversely related to the concentrations of dissolved organic carbon in the soil solutions.The results demonstrate that Ni availability to plants is not only affected by total concentration of Ni in the soil solution and the rate of replenishment from the solid phase, but also by Ni species, which can differ considerably between soil types.     

The effects of nematode resistant and susceptible spring oat cultivars and aldicarb on the cereal cyst nematode Heterodera avenae and yields in contrasting soil types

The effects of the cereal cyst-nematode, Heterodera auenae Woll. on resistant and susceptible oat cultivars, with and without aldicarb treatment, were compared on a clay-with-flints soil at Rothamsted and a loamy sand at Woburn. At both sites, when H. auenae was extremely scarce, yields were not further enhanced by aldicarb. At Rothamsted aldicarb increased yields by 48–72% when H. auenae averaged 10 eggs/g soil. At Woburn, aldicarb increased yields of both susceptible and resistant varieties by 80–90% with 20 eggs/g. The resistant varieties conferred yield benefits in the following oat crop equal to the residual effects of aldicarb applied before the previous crop, demonstrating that H. auenae was wholly responsible for the yield losses. Nematode resistant oats suffered as much or more damage from root invasion by H. auenae juveniles as the susceptible varieties but the resulting decrease in nematode numbers led to considerable yield improvements in the following year. At Woburn in 1977, when formalin was an added treatment, fewer females were infected by parasitic fungi and post-crop egg numbers were greater.     

Accumulation of zinc and cadmium by Cytophaga johnsonae

Passive and active accumulation of zinc and cadmium by a common soil and freshwater bacterium, Cytophaga johnsonae, was studied using a radio-tracer batch distribution technique. The effects of variation of pH (3–10), as well as of ionic strength (0.007 and 0.07 m) on passive accumulation of the metals were examined. For both zinc and cadmium, accumulation was mainly due to passive processes, such as surface adsorption and/or diffusion into the periplasm. However, at low zinc concentrations, accumulation increased when glucose was added, suggesting an active uptake; at higher zinc concentrations such uptake was not detected, probably because it was masked by the stronger sorption properties of the cell wall. Adsorption of the metals was pH dependent: at higher ionic strength, accumulation was enhanced at pH values above 7; at lower ionic strength, adsorption differed and was markedly higher, with increased accumulation between pH 5 and 8.     

Uptake and Distribution of Stable Strontium in 26 Cultivars of Three Crop Species: Oats,Wheat, and Barley for Their Potential Use in Phytoremediation

The main objective of this study was to investigate the accumulation and distribution of strontium (Sr) in 26 cultivars of wheat (Triticum aestivum L.), husk oat (Avena sativa L) and naked oat (Avena nuda), and barley (Hordeum vulgare L.) for their potential use in phytoremediation.Sr levels had no effect on the accumulation of shoot biomass at tillering or at maturity. Mean shoot Sr concentration of naked oat and barley at tillering was significantly (P < 0.05) higher than that of wheat; Neimengkeyimai-1, a naked oat cultivar, had the highest Sr concentrations. At maturity, of four naked oat cultivars, Neimengkeyimai-1 had the highest Sr content at all measured Sr levels. Leaves had the highest Sr concentrations, followed by roots and straw, and then grain with the lowest. Mean enrichment coefficients from soil to shoots ranged from 0.521 to 1.343; the percentage of stable Sr removed from the soil to the shoots at harvest time was more than 1.4% after 120 days. Neimengkeyimai-1 could be used as a model for further research to find more effective cultivars; and naked oat plants could be selected for phytoremediation to clean up contaminated soil.     

Effects of AM Inoculation and Organic Amendment, Alone or in Combination, on Growth, P Nutrition, and Heavy-Metal Uptake of Tobacco in Pb-Cd-Contaminated Soil

As toxic pollutants commonly found in tobacco (Nicotiana tabacum L.) products, lead (Pb) and cadmium (Cd) can enter the human body via smoking and thus pose a potential health risk to smokers. We conducted a greenhouse experiment to study the effects of arbuscular mycorrhizal (AM) inoculation with Glomus intraradices BEG 141 and organic amendment with cattle manure, alone or in combination, on the growth, P nutrition, and heavy-metal uptake by tobacco plants grown in soil to which was added Pb-Cd at 0/0, 350/1, 500/10, and 1,000/100?mg?kg^?1, respectively. In general, AM colonization and plant growth were greatly reduced by Pb-Cd contamination, whereas organic amendment alleviated Pb-Cd stress and showed some beneficial effects on AM symbiosis and some soil parameters. AM inoculation, alone or in combination with organic amendment, increased plant dry weights and improved P nutrition significantly at all Pb-Cd addition levels, and, in most cases, it decreased Pb and Cd concentrations in tobacco plants and DTPA-extractable concentrations in soil. AM inoculation increased total glomalin-related soil protein (GRSP) concentrations in soil to which Pb-Cd was added. The higher soil pH and GRSP contents and the lower DTPA-extractable Pb and Cd concentrations contributed by AM inoculation and/or organic amendment may be contributing factors that lead to higher growth promotion and lower metal toxicity and uptake by plants. Our findings suggest that AM inoculation in combination with organic manure may be a potential method for not only tobacco production but phytostabilization of Pb-Cd-contaminated soil.