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1.
Influence of VA-mycorrhiza on heavy metal uptake of oat (Avena sativa L.) from soils differing in heavy metal contamination The heavy metal uptake of mycorrhizal oat-plants (Avena sativa L.) was evaluated in pot experiments with two soils differing in heavy metal accumulation. The effect of the fungal isolates on the uptake of the immobile metals Zn and Cu differed between the two soils: In the soil “Kleinlinden” mycorrhizal colonization increased heavy metal uptake by up to 37%. In the highly contaminated soil “München”, mycorrhizal infection lead to a higher uptake (max. 59 %) in roots but to a reduced translocation to the aerial plant fractions. The higher uptake of Zn and Cu into the roots was related to the higher heavy metal concentrations in this soil. The Cd uptake showed no difference between the two soils, but was increased in the roots by VAM together with a lower translocation into the shoots. VAM-formation changed the root architecture by increasing the specific root length (m g?1 root dry matter) and the total root length (km per pot). This increased absorbing surface of the roots was a major, but not the only cause for the differences in heavy metal uptake.  相似文献   

2.
Contamination of soils with heavy metals becomes more and more a problem in many countries all over the world. In areas where metal contaminated soils are used for food crop production, metals relatively mobile within the plant, such as cadmium (Cd) and zinc (Zn) can easily come into the food chain with great risks for human health. Since bioavailability of heavy metals in soils varies with soil and plant characteristics, e.g., mineralogical and organic matter properties of the soil and plant metal susceptibility, prediction of heavy metal uptake by plants by the common soil and plant chemical analysis techniques is often unreliable. Recently, the use of biomarkers has been suggested to be a suitable technique complementing chemical soil analysis. Therefore, the usefulness of the biomarker phytochelatin (PC), a non‐protein thiol, specifically induced in plants suffering from heavy metal stress, was tested. Maize (Zea mays L.) plants were exposed to excess copper (Cu) or Cd in nutrient solution systems and metal and PC concentrations were monitored in plant shoot and root. Results clearly illustrated that very soon after plant exposure to the metal, PC induction started, especially in plant roots. Phytochelatin seems to be a useful early warning system for heavy metal stress in plants.  相似文献   

3.
Bioaugmentation is a promising method for assisting phytoextraction of heavy metals from contaminated soil, and the development of bioaugmentation-assisted phytoextraction requires the understanding of the mechanism involved in the interaction between plants and inocula. In this study, a pot study was conducted to evaluate the effect of bacterial endophyte Pseudomonas sp. Lk9 which can produce biosurfactants, siderophores and organic acids on the growth and metal uptake of Cd-hyperaccumulator Solanum nigrum L. growing in multi-metal-contaminated soil. The results revealed that Lk9 inoculation could improve soil Fe and P mineral nutrition supplies, enhance soil heavy metal availability, and affect host-mediated low-molecular-weight organic acids secretion, thereby significantly increasing S. nigrum shoot dry biomass by 14% and the total of Cd by 46.6%, Zn by 16.4% and Cu by 16.0% accumulated in aerial parts, compared to those of non-inoculated control. The assessment of phytoextraction showed that Lk9 inoculation elevated the bioaccumulation factor of Cd (28.9%) and phytoextraction rates of all metals (17.4%, 48.6% and 104.6% for Cd, Zn and Cu, respectively), while the translocation factors had negligible difference between Lk9 inoculation (3.30, 0.50 and 0.40 for Cd, Zn and Cu, respectively) and non-inoculated control (2.95, 0.53 and 0.42 for Cd, Zn and Cu, respectively). It was also found that the symbiotic association between S. nigrum and Lk9 significantly increased the soil microbial biomass C by 39.2% and acid phosphatase activity by 28.6% compared to those in S. nigrum without Lk9. This study would provide a new insight into the bioaugmentation-assisted phytoextraction of heavy metal-contaminated soils.  相似文献   

4.
通过盆栽试验研究了铅锌尾矿污染土壤中施用有机肥、石灰、蛭石和白云石等4种改良剂对光叶紫花苕生长发育、叶绿素及重金属Cu、Cd、Pb、Zn积累特性的影响,并分析了施用改良剂后土壤pH和有效态重金属含量的变化。结果表明,与对照相比,不同改良剂及其不同施用水平均能不同程度地提高土壤pH,显著降低土壤各重金属有效态含量,并显著抑制了Cd、Pb向光叶紫花苕地上部转移,降低了重金属在光叶紫花苕植株地上部的积累,改善了光叶紫花苕的生长和发育,光叶紫花苕株高、地上部鲜重和地下部鲜重、叶绿素含量均有不同程度增加,其中株高和地上部鲜重增加达到显著水平。4种改良剂的不同处理水平对光叶紫花苕地下部重金属含量影响均达显著水平。  相似文献   

5.
In Southern Spain, as in other semi-arid zones, plants used for the phytoremediation of heavy metal-contaminated sites must be able to withstand not only the challenging soil conditions but also seasonal drought and high temperatures. A pot assay was carried out to determine the ability of soil amendments to promote the survival and growth of the seedlings of two native species, Atriplex halimus L. (Amaranthaceae) and Bituminaria bituminosa (L.) C.H. Stirton (Fabaceae), in two heavy metal-contaminated soils, one of which also had a high level of arsenic (As). Restriction of A. halimus shoot growth in the non-amended soils appeared to be due to deficiency of nitrogen, phosphorus (P) and potassium (K) and in the more highly contaminated soil to lead (Pb) toxicity. Shoot biomass of A. halimus in the more highly contaminated soil was increased significantly by compost addition, due to increased uptake of K and P and decreased tissue Pb. The lack of effect of compost on B. bituminosa growth in this soil, despite a large increase in tissue K, may have been due to elevated tissue levels of As and Pb and the high soil salinity. The combination of A. halimus and compost addition seems appropriate for the phytostabilisation of contaminated semi-arid sites.  相似文献   

6.
利用培养试验和盆栽试验研究了一株无色菌(Achromatium sp.)对复合污染土壤上Cu、Zn的溶出效果及其对海州香薷(Elsholtzia splendens)生长和Cu、Zn吸收性的影响.结果表明,菌株在培养试验(pH = 4.65)中的产酸效果较盆栽试验(7.3<pH<8.2)更佳;土壤溶液可溶性Cu与pH显著正相关,而可溶性Zn与pH显著负相关;和对照处理相比,无色菌处理提高海州香薷的生物量和地上部Cu浓度,显著(p<0.05)提高海州香薷对污染土壤中Cu的去除潜力.  相似文献   

7.
Effects of heavy metals on rhizobia and the symbiotic association with leguminous hosts are currently unclear. To investigate this problem, we examined Rhizobium meliloti (microsymbiont) and alfalfa (Medicago sativa) (macrosymbiont) collected from soils contaminated with varying concentrations of heavy metals (varying distances from a Zn smelter operating 90 yr.). Soil populations of R. meliloti were not correlated with metal concentrations in soil. The lowest rhizobial population was found in the soil with the highest extractable metal concentrations, but the highest populations were found in soil which was moderately contaminated. A greenhouse study in which alfalfa was grown in the same soils showed no significant trend for nodulation or nitrogenase activity of roots. Highest nodule number and nitrogenase activity were observed in those soils which had the lowest population of R. meliloti. When the heavy metal Minimum Inhibitory Concentration (MIC) of individual isolates was examined, no correlation was found between the MIC and soil metal concentration (total, or water or 0.01 M Ca(NO3)2 extractable).These results indicate that even in highly contaminated soils, metal activity was not high enough to exert an antagonistic influence on the soil rhizobial population or the symbiotic association between alfalfa and R. meliloti.  相似文献   

8.
The mobility and migration capacity of Zn in the soil-plant system were studied in a series of pot experiments with barley as a test plant. The parameters of Zn accumulation depending on the metal concentrations in soils and soil solutions were estimated by soil and water culture methods. Experiments with barley in water culture were performed on a nutrient (soil) solution extracted from soddy-podzolic soil (Albic Retisol (Loamic, Ochric)) to which Zn2+ was added to reach working concentrations increasing from 0.07 to 430 μM. Different responses of barley plants to changes in the concentration of Zn in the studied soil were identified. Ranges of the corresponding concentrations in the soil and aboveground barley biomass were determined. Parameters of Zn accumulation by test plants were determined depending on the metal content in soddypodzolic soil and the soil solution. A new method was proposed for evaluating the buffer capacity of soils with respect to a heavy metal (Zn) using test plants (BCS(P)Zn). The method was used to evaluate the buffering capacity of loamy sandy soddy-podzolic soil. The considered methodological approach offers opportunities for using data obtained during the agroecological monitoring of agricultural lands with heavy metals (HMs), including the contents of exchangeable HMs and macroelements (C and Mg) in soils and concentrations of HMs and (Ca + Mg) in plants, in the calculation of the buffering capacity of the surveyed soils for HMs.  相似文献   

9.
Abstract

The simultaneous incorporation of heavy metals into the soil is still a matter of great concern. Interaction (competitive sorption) between these metals and the soil solid phase may result in a deterioration of soil quality which relies basically on amounts of alkaline cations saturating soils sorptive complex. Results of this study indicate that Pb, Cu, C d, and Zn have induced solution pH decreases which were more intensive at highest metal loading rates. Partition parameters (Kd)-based sequences showed that Pb and Cu were more competitive than Cd and Zn and the overall selectivity sequence followed: Pb > Cu > Cd > Zn. Metal loadings and their competitive sorption have led to a strengthened displacement of alkaline cations (i.e. Ca2+, Mg2+, K+, Na+), especially of Ca2+ as a factor “stabilizing” soil sorptive complex. Such metals impact jointly with soils acidification are of great environmental concern since tremendous amounts of alkaline cations (especially Ca2+) may be potentially leached out, irrespective of the degree of soil contamination, as evidenced in the current study. High and positive ΔG values implied that the studied soils were characterized by generally low concentrations of exchangeable potassium which required high energy to get displaced (desorbed). Further studies on heavy metal uncontaminated or contaminated areas should be undertaken to provide with data which should be used for predictions on changes related to soil buffering capacity as impacted by heavy metal inputs.  相似文献   

10.
刈割对六种牧草吸收重金属和修复污染土壤潜力的研究   总被引:1,自引:0,他引:1  
The pollution of soils by heavy metals has dramatically increased in recent decades. Phytoextraction is a technology that extracts elements from polluted soils using hyperaccumulator plants. The selection of appropriate plant materials is an important factor for successful phytoextraction in field. A field study was conducted to compare the efficiency of six high-biomass forage species in their phytoextraction of heavy metals (Cd, Pb and Zn) from contaminated soil under two harvesting strategies (double harvesting or single harvesting). Among the tested plants, amaranth accumulated the greatest amounts of Cd and Zn, whereas Rumex K-1 had the highest amount of Pb in the shoot under both double and single harvesting. Furthermore, double harvesting significantly increased the shoot biomass of amaranth, sweet sorghum and sudangrass and resulted in higher heavy metal contents in the shoot. Under double harvesting, the total amounts of extracted Cd, Pb and Zn (i.e., in the first plus second crops) for amaranth were 945, 2 650 and 12 400 g ha-1, respectively, the highest recorded among the six plant species. These results indicate that amaranth has great potential for the phytoextraction of Cd from contaminated soils. In addition, the double harvesting method is likely to increase phytoextraction efficiency in practice.  相似文献   

11.
The main objective of this study was to compare the effectiveness of different methods (heavy metals in pore water (PW), diffusive gradients in thin films (DGT), diethylene triamine pentaacetic acid (DTPA) extraction, and total heavy metals (THM) in soil) for the assessment of heavy metal bioavailability from soils having various properties and heavy metal contents. The effect of soil heavy metal pollution on shoot yield and sulfatase enzyme activity was also studied. Wheat (Triticum aestivum) was grown in different soils from Spain (n?=?10) and New Zealand (n?=?20) in a constant environment room for 25 days. The bioavailabilities of Cd, Cr, Cu, Ni, Pb, and Zn were assessed by comparing the metal contents extracted by the different methods with those found in the roots. The most widely applicable method was DGT, as satisfactory Cu, Ni, Pb, and Zn root concentrations were obtained, and it was able to distinguish between low and high Cr values. The analysis of the metal concentrations in PW was effective for the determination of Cr, Ni, and Zn content in root. Copper and Pb root concentrations were satisfactorily assessed by DTPA extraction, but the method was less successful with determining the Ni and Cr contents and suitable just to distinguish between high and low concentrations of Zn. The THM in soil method satisfactorily predicted Cu and Pb root concentrations but could only be used to distinguish between low and high Cr and Zn values. The Cd root concentration was not successfully predicted for any of the used methods. Neither shoot yield nor sulfatase enzyme activity was affected by the metal concentrations.  相似文献   

12.
On numerous occasions, rhizosphere microbial activities have been identified as a key factor in metal phytoavailability to various plant species and in phytoremediation of metal-contaminated sites. For soil bioremediation efforts in heavy metal contaminated areas, microbes adapted to higher concentrations of heavy metals are required. This study was a field survey undertaken to examine rhizosphere microbial communities and biogeochemistry of soils associated with Zn accumulation by indigenous willows (Salix purpurea L.) in the naturally metalliferous peat soils located near Elba, NY. Soil and willow leaf samples were collected from seven points, at intervals 18 m apart along a willow hedgerow, on four different dates during the growing season. Soil bacterial community composition was characterized by terminal restriction fragment length polymorphism (T-RFLP) analysis and a 16S clone library was created from the rhizosphere of willows and soils containing the highest concentrations of Zn. Bacterial community composition was correlated with soil sulfate, but not with soil pH. The clone library revealed comparable phylogenetic associations to those found in other heavy metal-contaminated soils, and was dominated by affiliations within the phyla Acidobacteria (32%), and Proteobacteria (37%), and the remaining clones were associated with a wide array of phyla including Actinobacteria, Gemmatimonadetes, Planctomycetes, Verrucomicrobia, Bacteriodetes, and Cyanobacteria. Diverse microbial populations were present in both rhizosphere and bulk soils of these naturally metalliferous peat soils with community composition highly correlated to the soil sulfate cycle throughout the growing season indicative of a sulfur-oxidizing rhizosphere microbial community. Results confirm the importance of soil characterization for informing bioremediation efforts in heavy metal contaminated areas and the reciprocity that microbial communities uniquely adapted to specific conditions and heavy metals may have on an ecosystem.  相似文献   

13.
Abstract

Phytoremediation is increasingly used to remediate metal contaminated soils. However, in order to provide technically efficient phytoremediation of contaminated sites the plant yield and metal uptake have to be enhanced dramatically. The aim of the study was to find appropriate combination of plant species and fertilizers capable of improving yields of the plants and stimulate a transfer of metals to more available to the plants forms. Wheat Triticum vulgare was used for the phytoremediation research. To increase yield of crops and enhance mobility of metals in the rhizosphere the soils were amended with three fertilizers (urea, horse manure, and “ispolin”). Short-term (36 d) vegetation test showed that concentrations of heavy metals in the plants grown in contaminated soil (from site 2) were significantly higher than those in the plants grown in clean soil (from site 1). Growth of wheat resulted in a decrease of Cd content in the soil. Amendment of the contaminated soil with urea enhanced the effect and the decrease of Cd concentration in the soil was more significant. The best effect was demonstrated after application of ispolin: concentrations of Cd, Cu, Pb, and Zn in the rhizosphere decreased 1.2–1.4 times as compared with those in the initial contaminated soil (the decrease was statistically significant).  相似文献   

14.
Thlaspi caerulescens J. and C. Presl is a Zn-hyperaccumulatingplant which has aroused considerable interest with respect to its possible use for phytoremediation of Zn-contaminated soils. In this work, a British population of T. caerulescens, from a soil which was found to have relatively high concentrations of water-extractable Cu (0.22 mg L-1), Pb (0.99 mg L-1) and Zn (6.49 mg L-1), was studied. Its ability to grow and accumulate Zn from hydroponic nutrient solution in the presence of elevated concentrations of Cu and/or Pb was investigated. The chosen concentrations of Cu, Pb and Zn were based on reported water-soluble concentrations of these heavy metals in contaminated soils. When supplied with 32.7 mg L-1 Zn, plants accumulated 19 780 mg kg-1 Zn in their shoot dry matter. This concentration declined by 9.3, 87 and 84% respectively when 5.0 mg L-1 Pb, 1.0 mg L-1 Cu or 2.0 mg L-1 Cu were included in the nutrient solution. Despite the apparent adaptation of this population of T. caerulescens to a Zn/Pb/Cu-contaminated soil, these Cu treatments strongly inhibited growth, but the Pb treatment did not affect growth significantly.  相似文献   

15.
In this study, we investigated, with pot experiments, whether combined application of zeolites and vermicompost is more effective than single application on plant growth and heavy metals’ uptake in a heavy metal contaminated soil. The results showed that co-application of these amendments decreased zinc (Zn) and cadmium (Cd) availability by their redistribution from plant available forms to organic matter and metal oxide associated fractions. While, the addition of vermicompost and zeolites increased the lead (Pb) concentration significantly in the soluble/exchangeable form as compared with the control. Applying vermicompost individually or in combination with zeolites markedly increased plant biomass. Single zeolites and vermicompost reduced Zn and Pb contents of corn roots and shoots compared to un-treated soil, but less compared to the combined zeolite and vermicompost treatments. The results obtained suggest that co-application of zeolites and vermicompost could be an option for immobilizing Cd, Pb, and Zn in heavy metal contaminated soils.  相似文献   

16.
《Applied soil ecology》2006,34(3):286-293
Heavy metals adversely influence microorganisms, affecting their growth, morphology and activities. Metals also can exert a selective pressure on the organisms, resulting in microbial populations with higher tolerance to metals. Given the importance of legumes in animal and human consumption and their use in maintaining soil fertility, some attention has been given to the effects that heavy metals exert on Rhizobium isolates. In this context, Rhizobium leguminosarum biovar viciae was isolated from areas with different heavy metal contents and their tolerances were compared. Alterations in the protein pool of Rhizobium populations were also evaluated. Physicochemical parameters were determined and heavy metal concentrations in soils were analysed by ICP-AES. Isolates were screened for their tolerance in YEM media supplemented with different heavy metals (Zn, Pb, Co, Cd, Ni, Cr). Proteins were extracted and separated by SDS-PAGE. EI1 and EI2 (engineering industries) soils presented the highest metal concentration, and were therefore the most polluted soils. Isolates showed different growth responses to heavy metals. C (control soil) and M (mines) isolates were less tolerant than EI1, EI2 and CI (chemical industries) isolates. Metals influenced their protein profiles, most of the alterations corresponding to decreases in polypeptide expression. However, in tolerant isolates these alterations corresponding basically to increases, as occurred in CI isolates.This work suggests that there is a relationship between Rhizobium's tolerance, heavy metal soil contamination and alterations in protein pool. As a result, the analysis of protein alterations seems to be a good indicator to estimate the level of stress imposed on Rhizobium populations submitted to heavy-metal contamination.  相似文献   

17.
Heavy metal content of roots and shoots of vines (Vitis vinifera L.) after fertilization with garbage-sewage-sludge-compost The enrichment of Zn, Cu, Pb, Cd, Co, Ni and Cr from garbage-sewage-sludge-compost in vineyard soils, vines and must was studied in field-and pot-experiments. The following results were obtained: 1. In a field experiment, in which garbage-sewage-sludge-compost was applied, a marked soil enrichment of Zn, Cu, Pb, Cd and Cr was found. It was most evident at the 0–20 cm depth but also obvious at the 40–60 cm depth thus indicating downward migration. The soil was not enriched with Co and Ni. The heavy metal content of leaves, berries and must of riesling vines did not increase on the plots treated with garbage-sewage-sludge-compost. 2. In a pot trial, using an acid and an alkaline soil each mixed with garbage-sewage-sludge-compost, it was observed that only the uptake of Zn and Cu increased into the leaves, tendrils and wood of the riesling cuttings. In relation to the content of the substrate, the heavy metals were detected in the roots percentually in the following order: Cu, Cd > Zn > > Pb, Co, Ni, Cr The root contents were mostly substantially higher than those of the shoot. The migration from root to shoot decreased in the following percentual order: Zn > Cu > Cd, Pb 3. The heavy metal content decreased considerably from the roots to the upper plant organs. This was reflected in low concentrations of heavy metals in the vine must.  相似文献   

18.
This study investigates the impact of future climate change on heavy metal (i.e., Cd and Zn) transport from soils to surface waters in a contaminated lowland catchment. The WALRUS hydrological model is employed in a semi-distributed manner to simulate current and future hydrological fluxes in the Dommel catchment in the Netherlands. The model is forced with climate change projections and the simulated fluxes are used as input to a metal transport model that simulates heavy metal concentrations and loads in quickflow and baseflow pathways. Metal transport is simulated under baseline climate (“2000–2010”) and future climate (“2090–2099”) conditions including scenarios for no climate change and climate change. The outcomes show an increase in Cd and Zn loads and the mean flux-weighted Cd and Zn concentrations in the discharged runoff, which is attributed to breakthrough of heavy metals from the soil system. Due to climate change, runoff enhances and leaching is accelerated, resulting in enhanced Cd and Zn loads. Mean flux-weighted concentrations in the discharged runoff increase during early summer and decrease during late summer and early autumn under the most extreme scenario of climate change. The results of this study provide improved understanding on the processes responsible for future changes in heavy metal contamination in lowland catchments.  相似文献   

19.
[目的]稻田土壤重金属污染是当前农产品安全生产关注的重要问题.本文比较分析工业和农业污染源稻田土壤重金属的赋存形态及水稻吸收运移,以期为稻田土壤重金属污染控制提供参考.[方法]在长江中下游地区调查选取工业源和农业源重金属污染稻田各27块,在水稻成熟期使用抖根法采集根际土壤及水稻根系和籽粒样品,采用Tessier七步提取...  相似文献   

20.
The significance of arbuscular mycorrhizal fungi (AMF) in soil remediation has been widely recognized because of their ability to promote plant growth and increase phytoremediation efficiency in heavy metal (HM) polluted soils by improving plant nutrient absorption and by influencing the fate of the metals in the plant and soil. However, the symbiotic functions of AMF in remediation of polluted soils depend on plant–fungus–soil combinations and are greatly influenced by environmental conditions. To better understand the adaptation of plants and the related mycorrhizae to extreme environmental conditions, AMF colonization, spore density and community structure were analyzed in roots or rhizosphere soils of Robinia pseudoacacia. Mycorrhization was compared between uncontaminated soil and heavy metal contaminated soil from a lead–zinc mining region of northwest China. Samples were analyzed by restriction fragment length polymorphism (RFLP) screening with AMF-specific primers (NS31 and AM1), and sequencing of rRNA small subunit (SSU). The phylogenetic analysis revealed 28 AMF group types, including six AMF families: Glomeraceae, Claroideoglomeraceae, Diversisporaceae, Acaulosporaceae, Pacisporaceae, and Gigasporaceae. Of all AMF group types, six (21%) were detected based on spore samples alone, four (14%) based on root samples alone, and five (18%) based on samples from root, soil and spore. Glo9 (Rhizophagus intraradices), Glo17 (Funneliformis mosseae) and Acau3 (Acaulospora sp.) were the three most abundant AMF group types in the current study. Soil Pb and Zn concentrations, pH, organic matter content, and phosphorus levels all showed significant correlations with the AMF species compositions in root and soil samples. Overall, the uncontaminated sites had higher species diversity than sites with heavy metal contamination. The study highlights the effects of different soil chemical parameters on AMF colonization, spore density and community structure in contaminated and uncontaminated sites. The tolerant AMF species isolated and identified from this study have potential for application in phytoremediation of heavy metal contaminated areas.  相似文献   

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