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1.
矿区分离丛枝菌根真菌对万寿菊吸Cd潜力影响 总被引:2,自引:0,他引:2
盆栽试验研究土壤不同施Cd水平(0、5、20、50μg/g)下,接种矿区污染土壤中丛枝菌根真菌对万寿菊根系侵染率、植株生物量及Cd吸收与分配的影响。结果表明:接种丛枝菌根真菌显著提高Cd胁迫下万寿菊的根系侵染率和植株生物量;随着施Cd水平提高,各处理植株Cd浓度显著增加。各施Cd水平下万寿菊地上部Cd吸收量远远高于根系Cd吸收量,在土壤施Cd量达到50μg/g时,接种处理地上部Cd吸收量是根系的3.48倍,对照处理地上部Cd吸收量是根系的1.67倍;同一施Cd水平下接种处理植株Cd吸收量要显著高于对照。总体上,试验条件下污染土壤中分离的丛枝菌根真菌促进了万寿菊对土壤中Cd的吸收,并在一定程度上增加Cd向地上部分的运转,表现出植物提取的应用潜力。 相似文献
2.
Mycorrhizal fungus colonization of roots may modify plant metal acquisition and tolerance. In the present study, the contribution
of the extraradical mycelium of an arbuscular mycorrhizal (AM) fungus, Glomus mosseae (BEG 107), to the uptake of metal cations (Cu, Zn, Cd and Ni) by cucumber (Cucumis sativus) plants was determined. The influence of the amount of P supplied to the hyphae on the acquisition and partitioning of metal
cations in the mycorrhizal plants was also investigated. Pots with three compartments were used to separate root and root-free
hyphal growing zones. The shoot concentration of Cd and Ni was decreased in mycorrhizal plants compared to non-mycorrhizal
plants. In contrast, shoot Zn and Cu concentrations were increased in mycorrhizal plants. High P supply to hyphae resulted
in decreased root Cu concentrations and shoot Cd and Ni concentrations in mycorrhizal plants. These results confirm that some
elements required for plant growth (P, Zn, Cu) are taken up by mycorrhizal hyphae and are then transported to the plants.
Conversely, Cd and Ni were transported in much smaller amounts by hyphae to the plant, so that arbuscular mycorrhizal fungus
colonization could partly protect plants from toxic effects of these elements. Selective uptake and transport of plant essential
elements over non-essential elements by AM hyphae, increased growth of mycorrhizal plants, and metal accumulation in the root
may all contribute to the successful growth of mycorrhizal plants on metal-rich substrates. These effects are stimulated when
hyphae can access sufficient P in soil. 相似文献
3.
Contribution of Ectomycorrhizal Fungi to Cadmium Uptake of Poplars and Willows from a Heavily Polluted Soil 总被引:2,自引:0,他引:2
Phytoextraction has been proposed in recent years as an environmentally and cost-efficient treatment technique for the remediation
of heavy-metal contaminated sites. In particular, plants that are fast growing, metal accumulating, and economically interesting,
such as sunflowers or trees, recently became more important in research on phytoextraction. Heavy metal uptake of trees can
be strongly influenced by ectomycorrhizal fungi. We investigated the possibility of enhancing phytoextraction of Cd by willows
(Salix viminalis) and poplars (Populus canadensis) in association with three well known ectomycorrhizal fungi (Hebeloma crustuliniforme, Paxillus involutus and Pisolithus tinctorius). A pot experiment was conducted using Cd polluted soil from a contaminated site. Four replicates of each combination of
fungus and tree species, and controls without fungal inoculum, were set up. After a growth period of 11 weeks, yields and
Cd concentrations in roots, stems, and leaves were measured. In addition, the total Cd uptake, the transfer to roots, and
the translocation to stems and leaves were calculated. The association of P. canadensis with P. involutus led to a highly significant increase of Cd concentrations, in particular in the leaves, which contained 2.74 ± 0.34 mg Cd
per kg dry matter. Compared to the control this is an enhancement of nearly 100%. The fungi also significantly enhanced the
translocation from the roots to the leaves, leading to a concentration ratio (leaves/roots) of 0.32 ± 0.06 compared to 0.20
± 0.02 of the control plants. Additionally, P. involutus significantly enhanced the total Cd extraction by P. canadensis. Similar effects were not observed by other fungi or in association with S. viminalis. 相似文献
4.
A pot culture experiment and a field experiment were carried out separately to study heavy metal (HM) uptake from soil contaminated
with Cu, Zn, Pb and Cd by Elsholtzia splendens Nakai ex F. Maekawa inoculated with arbuscular mycorrhizal (AM) fungi and the potential for phytoremediation. The HM-contaminated
soil in the pot experiment was collected from the field experiment site. Two AM fungal inocula, MI containing only one AM
fungal strain, Glomus caledonium 90036, and M II consisting of Gigaspora margarita ZJ37, Gigaspora decipens ZJ38, Scutellospora gilmori ZJ39, Acaulospora spp. andGlomus spp., were applied to the soil under unsterilized conditions. In the pot experiment, the plants were harvested after 24 weeks
of growth. Mycorrhizal colonization rate, plant dry weight (DW) and P, Cu, Zn, Pb, Cd concentrations were determined. MI-treated
plants had higher mycorrhizal colonization rates than MII-treated plants. Both MI and MII increased shoot and root DW, and
MII was more effective than MI. In shoots, the highest P, Cu, Zn and Pb concentrations were all observed in the plants treated
with MII, while MI decreased Zn and Pb concentrations and increased P but did not alter Cu, and Cd concentrations were not
affected by either of two inocula. In roots, MII increased P, Zn, Pb concentrations but did not alter Cu and Cd, and MI did
not affect P, Cu, Zn, Pb, Cd concentrations. Cu, Zn, Pb, Cd uptake into shoots and roots all increased in MII-treated plants,
while in MI-treated plants, Cu and Zn uptake into shoots and Cu, Zn, Pb, Cd into roots increased but Pb and Cd uptake into
shoots decreased. In general, MII was more effective than MI in promoting plant growth and HM uptake. The field experiment
following the pot experiment was carried out to investigate the effects of MII under field conditions. The 45-day-old nonmycorrhizal
and MII-colonized seedlings of E. splendens were transplanted to HM-contaminated plots and harvested after 5 months. MII-inoculation increased shoot DW and shoot P,
Cu, Zn, Pb concentrations significantly but did not alter shoot Cd concentrations, which led to higher uptake of Cu, Zn, Pb,
Cd by E. splendens shoots. These results indicate that the AM fungal consortium represented by MII can benefit phytoextraction of HMs and therefore
play a role in phytoremediation of HM-contaminated soils. 相似文献
5.
Arbuscular mycorrhiza decreases cadmium phytoextraction by transgenic tobacco with inserted metallothionein 总被引:8,自引:0,他引:8
The effect of arbuscular mycorrhiza (AM) on the phytoextraction efficiency of transgenic tobacco with increased ability to tolerate and accumulate cadmium (Cd) was tested in a pot experiment. The tobacco plants bearing the yeast metallothionein CUP1 combined with a polyhistidine cluster were compared to non-transgenic tobacco of the same variety at four Cd concentrations in soil, non-inoculated or inoculated with two isolates of the AM fungus Glomus intraradices. Mycorrhizal inoculation improved the growth of both the transgenic and non-transgenic tobacco and decreased Cd concentrations in shoots and root to shoot translocation. Differences were found between the two AM fungal isolates: one isolate supported more efficient phosphorus uptake and plant growth in the soil without Cd addition, while the other isolate alleviated the inhibitory effect of cadmium on plant growth. The resulting effect of inoculation on Cd accumulation was dependent on Cd level in soil and differed between the more Cd tolerant transgenic plants and the less tolerant non-transgenic plants. Mycorrhiza mostly decreased the phytoextraction efficiency of transgenic plants while increased that of non-transgenic plants at Cd levels in soil inhibitory to tobacco growth. Mechanisms of the observed effects of inoculation on growth and Cd uptake are discussed as well as the possible implications of the results for the exploitation of AM in phytoextraction of heavy metals from contaminated soils. 相似文献
6.
DGT-measured fluxes explain the chloride-enhanced cadmium uptake by plants at low but not at high Cd supply 总被引:1,自引:0,他引:1
Carla Oporto Erik Smolders Fien Degryse Liesbeth Verheyen Carlo Vandecasteele 《Plant and Soil》2009,318(1-2):127-135
The technique of diffusive gradients in thin films (DGT) has been shown to be a promising tool to assess metal uptake by plants in a wide range of soils. With the DGT technique, diffusion fluxes of trace metals through a diffusion layer towards a resin layer are measured. The DGT technique therefore mimics the metal uptake by plants if uptake is limited by diffusion of the free ion to the plant roots, which may not be the case at high metal supply. This study addresses the capability of DGT to predict cadmium (Cd) uptake by plants at varying Cd supply. To test the performance of DGT in such conditions, we used the chloride (Cl?) enhancement effect, i.e. the increase in Cd solution concentrations—due to chloride complexation of Cd—and Cd uptake with increasing Cl? concentrations, as previously characterized in pot, field and solution culture experiments. The uptake of Cd by spinach was assessed in soil amended with Cd (0.4–10.5 mg Cd kg?1) and NaCl (up to 120 mM) in a factorial design. Treatments with NaNO3 were included as a reference to correct for ionic strengths effects. The effect of Cl? on the shoot Cd concentrations was significant at background Cd but diminished with increasing soil Cd. Increasing Cl? concentrations increased the root area based Cd uptake fluxes by more than a factor of 5 at low soil Cd, but had no significant effect at high soil Cd. Short-term uptake of Cd in spinach from nutrient solutions confirmed these trends. In contrast, increasing Cl? concentrations increased the DGT measured fluxes by a factor of 5 at all Cd levels. As a result, DGT fluxes were able to explain soil Cl? effects on plant Cd concentrations at low but not at high Cd supply. This example illustrates under which conditions DGT mimics trace metal bioavailability. If biouptake is controlled by diffusive limitations, DGT should be a successful tool for predicting ion uptake across different conditions. 相似文献
7.
碱性土壤盐化过程中阴离子对土壤中镉有效态和植物吸收镉的影响 总被引:3,自引:0,他引:3
镉是土壤环境中对土壤质量有着极其重要影响的污染物之一,低含量下就能对人体和动物产生危害.镉在土壤中的有效态既决定了它的生物有效性及对环境的危害程度,又是人们对受污染土壤进行治理和修复的基础.作为盐化土壤中的典型组分,无机盐不可避免对镉的有效态及生物有效性等地球化学行为产生明显影响.研究了碱性土壤盐化过程中无机盐阴离子对土壤中镉有效态和植物吸收镉影响.研究方法为:以钠盐为例,实验研究了碱性土壤盐化过程中无机盐阴离子对土壤中镉有效态的影响;通过油菜种植试验,分析了无机盐阴离子对土壤中镉生物有效性的影响.研究结果表明,土壤盐化过程中,土壤溶液中Cl-浓度较低时,土壤中镉的有效态含量随Cl-浓度增加而增大,但当土壤中Cl-/Cd的比值大于100∶1时,土壤中镉的有效态含量达到最大值.土壤溶液中SO42-含量对土壤中镉有效态含量的影响不明显;随着土壤溶液中HCO3-含量的增加,土壤中镉的有效态含量明显减少.由于Cl-、SO42-是土壤溶液中的主要成分,随着盐度的增加,镉的有效态含量增加.油菜种植试验显示,当土壤中Cl-的含量增加时,土壤中镉的有效态含量增加,有利于植物对镉的吸收,因此油菜中镉的含量随土壤中Cl-的含量增加而增加,但当土壤有效态含量超过2 mg/kg后,油菜吸收镉已经达到最大.随着土壤溶液中SO42-浓度的增加,油菜中镉含量基本不变;土壤溶液中HCO3-的含量增加,植物中镉的含量随土壤中HCO3-含量增加而减少.这些特征与土壤镉有效态变化相吻合.通过各种措施控制土壤盐度和调节阴离子类型和含量,有利于降低土壤中镉的有效态含量,减轻镉的活化;农业生产中适当调整无机肥料的种类,可以减少农作物对镉的吸收. 相似文献
8.
Arbuscular mycorrhizal contribution to heavy metal uptake by maize (Zea mays L.) in pot culture with contaminated soil 总被引:10,自引:0,他引:10
In two pot-culture experiments with maize in a silty loam (P2 soil) contaminated by atmospheric deposition from a metal smelter, root colonization with indigenous or introduced arbuscular mycorrhizal (AM) fungi and their influence on plant metal uptake (Cd, Zn, Cu, Pb, Mn) were investigated. Soil was -irradiated for the nonmycorrhizal control. In experiment 1, nonirradiated soil provided the mycorrhizal treatment, whereas in experiment 2 the irradiated soil was inoculated with spores of a fungal culture from P2 soil or a laboratory reference culture, Glomus mosseae. Light intensity was considerably higher in experiment 2 and resulted in a fourfold higher shoot and tenfold higher root biomass. Under the conditions of experiment 1, biomass was significantly higher and Cd, Cu, Zn and Mn concentrations significantly lower in the mycorrhizal plants than in the nonmycorrhizal plants, suggesting a protection against metal toxicity. In contrast, in experiment 2, biomass did not differ between treatments and only Cu root concentration was decreased with G. mosseae-inoculated plants, whereas Cu shoot concentration was significantly increased with the indigenous P2 fungal culture. The latter achieved a significantly higher root colonization than G. mosseae (31.7 and 19.1%, respectively) suggesting its higher metal tolerance. Zn shoot concentration was higher in both mycorrhizal treatments and Pb concentrations, particularly in the roots, also tended to increase with mycorrhizal colonization. Cd concentrations were not altered between treatments. Cu and Zn, but not Pb and Cd root-shoot translocation increased with mycorrhizal colonization. The results show that the influence of AM on plant metal uptake depends on plant growth conditions, on the fungal partner and on the metal, and cannot be generalized. It is suggested that metal-tolerant mycorrhizal inoculants might be considered for soil reclamation, since under adverse conditions AM may be more important for plant metal resistance. Under the optimized conditions of normal agricultural practice, however, AM colonization even may increase plant metal absorption from polluted soils. 相似文献
9.
Rahat Shabir Muhammad Saqib Muhammad Shahid Ghulam Mustafa Shah Muhammad Akram 《International journal of phytoremediation》2018,20(7):739-746
In this study, we explored the effect of salinity on cadmium (Cd) tolerance and phytoremediation potential of Acacia nilotica. Two-month-old uniform plants of A. nilotica were grown in pots contaminated with various levels of Cd (0, 5, 10, and 15 mg kg?1), NaCl (0%, 0.5%, 1.0% (hereafter referred as salinity), and all possible combinations of Cd + salinity for a period of six months. Results showed that shoot and root growth, biomass, tissue water content and chlorophyll (chl a, chl b, and total chl a+b) contents decreased more in response to salinity and combination of Cd + salinity compared to Cd alone. Shoot and root K concentrations significantly decreased with increasing soil Cd levels, whereas Na and Cl concentrations were not affected significantly. Shoot and root Cd concentrations, bioconcentration factor (BCF) and translocation factor (TF) increased with increasing soil Cd and Cd + salinity levels. At low level of salinity (0.5%), shoot and root Cd uptake enhanced, while it decreased at high level of salinity (1.0%). Due to Cd tolerance, high shoot biomass and shoot Cd uptake, this tree species has some potential for phytoremediation of Cd from the metal contaminated saline and nonsaline soils. 相似文献
10.
This study investigated the effects of pH and nitrogen form and concentration on cadmium (Cd) uptake by potato (Solanum tuberosum L.) grown in hydroponic culture. Potato plants grown in a pH-buffered nutrient solution for 10 d were exposed for 24 h to 25 nM CdCl2 labelled with 109Cd. Plants showed a significantly higher Cd uptake and accumulation at pH 6.5 than at pH 4.5 and 5.5. Nitrogen supplied as nitrate (NO3 ?) generally resulted in a higher Cd uptake and accumulation than N supplied as ammonium (NH4 +). This effect was most pronounced at pH 6.5. The N concentration increasing from 6.5 to 26 mM resulted in a decreased Cd influx when either NO3 ? or NH4 + was used. Cd translocation to the shoot was increased when NO3 ? was used as the sole N source. In conclusion, pH had a strong influence on Cd uptake by roots and N form is especially important for Cd translocation within the potato plant. 相似文献
11.
Effects of sulfate on cadmium uptake by Swiss chard: II. Effects due to sulfate addition to soil 总被引:3,自引:0,他引:3
Sulfate complexation of Cd in nutrient solution has been shown to have little impact on Cd uptake by plants. This study examined the effect of sulfate added to soil on Cd concentrations in soil solution and Cd uptake by Swiss chard (Beta vulgaris L. cv. Fordhook Giant). Swiss chard was grown in soil which was wetted with complete nutrient solution containing equivalent salt concentrations of NaNO3 or Na2SO4. Plant growth was reduced by increasing both NO3 and SO4 concentrations in soil solution, with growth reductions similar for both salts. The Cd concentration in soil solution increased P< 0.05) more consistently with increasing concentrations of SO4 compared to NO3 in soil solution. Solution speciation, calculated with GEOCHEM-PC, showed significant increases of Cd2+ activities with increasing salt rates. Shoot Cd content in 19-day-old Swiss chard plants was marginally but significantly P <0.05) increased with increasing SO4 concentration but no effect was observed with increasing NO3 concentration. These results are compared with earlier work on the marked effect of Cl- salinity on Cd availability in Swiss chard. Possible mechanisms explaining the smaller effect of SO4 compared to Cl on Cd availability are proposed. 相似文献
12.
镉在土壤-香根草系统中的迁移及转化特征 总被引:1,自引:0,他引:1
以无植物组处理为对照,采用盆栽试验方式探讨不同Cd浓度胁迫条件下香根草根际土壤中重金属Cd的积累、迁移及转化特征。土壤Cd处理设4个浓度梯度,分别为0、2、20、80 mg/kg土壤干重。结果表明:(1)香根草可以显著降低土壤中生物有效态Cd和总Cd含量。(2)香根草各部分Cd积累量随处理浓度的增加和处理时间的延长而增加,90 d时80 mg/kg处理组地上部分和根的Cd积累量分别高达180.42 mg/kg和241.54 mg/kg。(3)各浓度Cd处理下,富集系数随着Cd处理浓度的增加而显著降低,随处理时间的延长而升高。(4)香根草地上部分Cd含量小于根部,各处理转移系数均小于1。随着处理时间的延长,中低浓度处理组的转移系数稍有降低,高浓度处理组的转移系数则显著上升。(5)种植香根草使其根际土中残渣态的Cd转化为生物有效态Cd,提高Cd清除效率。研究结果表明,香根草能够有效地吸收土壤中的Cd,降低土壤中总Cd含量,提高土壤安全性,可作为Cd污染地区植物修复的备选物种。 相似文献
13.
The aim of the present study was to evaluate the role of arbuscular mycorrhizal (AM) fungi on metal uptake, oxidative effects
and antioxidant defence mechanisms under cadmium (Cd) and lead (Pb) stresses in Cajanus cajan (L.) Millsp. (pigeonpea). Treatments consisted of two concentrations each of Cd (25 and 50 mg/kg of soil) and Pb (500 and
800 mg/kg of soil) singly as well as in combination. Both metals induced oxidative damage through increased lipid peroxidation,
electrolyte leakage and hydrogen peroxide levels, but Cd was found to be more toxic than Pb. Compared with the effects of
Cd or Pb alone, the combination of Cd and Pb acted synergistically; however, Pb immobilisation in soil controlled the uptake
of Cd in plants. There was a direct correlation between the type of genotype, heavy metal content and oxidative damage in
concentration dependent manner. Superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) increased under stress. The
toxicity symptoms of the metal stress were significantly higher in Sel-141-97 genotype when compared with Sel-85 N. The high
ratio of glutathione to its oxidised form, glutathione disulfide (GSH/GSSG), could be restored by means of higher glutathione
reductase (GR) activity and increased GSH synthesis in mycorrhizal stressed plants. AM inoculations with Glomus mosseae significantly arrested uptake of Cd and Pb into the root system and further translocation into the above ground parts and
led to decreased lipid peroxidation and electrolyte leakage. Increased activities of SOD, CAT, POX as well as GR were observed
in all mycorrhizal stressed plants. 相似文献
14.
滨海盐渍土壤中不同类型盐生植物富集镉的效应 总被引:2,自引:0,他引:2
为了利用被镉污染的滨海盐渍土壤,通过实验对比分析3种不同类型盐生植物对盐渍土中镉的富集效应,以期初步探明不同类型盐生植物在镉污染盐渍土壤修复中的效果。选择的3种盐生植物类型是:聚盐盐生植物,泌盐盐生植物和避盐盐生植物。通过温室盆栽实验,将植物在不同镉含量的盐渍土壤中种植培养60 d,测定和分析不同类型盐生植物对镉的生物浓缩因子、转移系数以及植株内地上部分和根部生物量和镉含量的变化。结果表明,不同镉含量的土壤对碱蓬和芦苇的生长影响较小,对二色补血草的生长影响较大。不同镉含量的土壤中,芦苇地上部分镉的生物浓缩因子变化差异不显著,并且其地上部分吸收镉的百分率较高。碱蓬和芦苇的转移系数大于二色补血草的转移系数,并且碱蓬的转移系数在不同镉含量的土壤中变化不显著;二色补血草的转移系数随着土壤中镉含量的增加而显著增大。3种盐生植物中,碱蓬最具修复镉污染盐渍土壤的潜力,这可能和它是聚盐盐生植物的生理类型有关。芦苇整个植株的地上部分富集镉的总量在3种植物中是最高的,因此,芦苇在镉含量较低时也可以做为镉污染盐渍土壤的修复材料。 相似文献
15.
16.
Cadmium mobilisation and plant availability – the impact of organic acids commonly exuded from roots
The present work highlights metal-organic acid interactions with special reference to their plant availability. Pot experiments were conducted to investigate the effect of various organic (carboxylic and amino) acids on the uptake and translocation of root-absorbed Cd by maize (Zea mays) plants grown in sand and soil culture. Statistically significant increases in Cd accumulation from Cd-treated plants in the presence of increasing concentrations of organic acids, suggest the existence of Cd-organic acid interactions in the soil-plant system. In order to support the above hypothesis of formation of organically bound Cd, separate experiments were performed to synthesize and estimate its various forms viz. cationic, anionic and neutral. The chemical nature of the organically bound forms was ascertained by electrophoretic experiments. Amino acids have been found to be less effective in the mobilisation of cadmium compared to carboxylic acids. The results are discussed on the basis of the potential of organic acids to form complexes with Cd. 相似文献
17.
We investigated uptake of Cd by arbuscular mycorrhizal (AM) maize inoculated with Glomus mosseae from a low-P sandy calcareous soil in two glasshouse experiments. Plants grew in pots containing two compartments, one for root and hyphal growth and one for hyphal development only. Three levels of Cd (0, 25 and 100 mg kg–1) and two of P (20 and 60 mg kg–1) were applied separately to the two compartments to assess hyphal uptake of Cd. Neither Cd nor P addition inhibited root colonization by the AM fungus, but Cd depressed plant biomass. Mycorrhizal colonization, P addition and increasing added Cd level led to lower Cd partitioning to the shoots. Plant P uptake was enhanced by mycorrhizal colonization at all Cd levels studied. When Cd was added to the plant compartment and P to the hyphal compartment, plant biomass increased with AM colonization and the mycorrhizal effect was more pronounced with increasing Cd addition. When P was added to the plant compartment and Cd to the hyphal compartment, plant biomass was little affected by AM colonization, but shoot Cd uptake was increased by colonization at the low Cd addition rate (25 mg kg–1) and lowered at the higher Cd rate (100 mg kg–1) but with no difference in root Cd uptake. These effects may have been due to immobilization of Cd by the fungal mycelium or effects of the AM fungus on rhizosphere physicochemical conditions and are discussed in relation to possible phytostabilization of contaminated sites by AM plants. 相似文献
18.
Leônidas Carrijo Azevedo Melo Luís Reynaldo Ferracciú Alleoni Frank Albert Swartjes Evandro Barbosa da Silva 《人类与生态风险评估》2012,18(4):888-901
The availability and uptake of Cd by lettuce (Lactuca sativa L.) in two common tropical soils (before and after liming) were studied in order to derive human health-based risk soil concentration. Cadmium concentrations ranging from 1 to 12 mg kg?1 were added to samples from a clayey Oxisol and a sandy-loam Ultisol under glasshouse conditions. After incubation, a soil sample was taken from each pot, the concentration of Cd in the soil was determined, lettuce was grown during 36 d, and the edible parts were harvested and analyzed for Cd. A positive linear correlation was observed between total soil Cd and the Cd concentration in lettuce. The amount of Cd absorbed by lettuce grown in the Ultisol was about twice the amount absorbed in the Oxisol. Liming increased the soil pH and slightly reduced Cd availability and uptake. CaCl2 extraction was better than DTPA to reflect differences in binding strength of Cd between limed and unlimed soils. Risk Cd concentrations in the Ultisol were lower than in the Oxisol, reflecting the greater degree of uptake from the Ultisol. The derived risk Cd values were dependent on soil type and the exposure scenario. 相似文献
19.
A pot culture experiment was carried out to study heavy metal (HM) phytoaccumulation from soil contaminated with Cu, Zn, Pb, and Cd by maize (Zea mays L.) inoculated with arbuscular mycorrhizal (AM) fungi (AMF). Two AM fungal inocula--MI containing only one AM fungal strain (Glomus caledonium 90036) and MII consisting of Gigaspora margarita ZJ37, Gigaspora decipens ZJ38, Scutellospora gilmori ZJ39, Acaulospora spp., and Glomus spp.--were applied to the soil under unsterilized conditions. The control received no mycorrhizal inoculation. The maize plants were harvested after 10 wk of growth. MI-treated plants had higher mycorrhizal colonization than MII-treated plants. Both MI and MII increased P concentrations in roots, but not in shoots. Neither MI nor MII had significant effects on shoot or root dry weight (DW). Compared with the control, shoot Cu, Zn, Pb, and Cd concentrations were decreased by MI but increased by MII. Cu, Zn, Pb, and Cd uptake into shoots and roots all increased in MII-treated plants, while in MI-treated plants Cu, Zn, and Pb uptake into shoots and Cd uptake into roots decreased but Cu, Zn, and Pb uptake into roots and Cd into shoots increased. MII was more effective than MI in promoting HM extraction efficiencies. The results indicate that MII can benefit HMphytoextraction and, therefore, show potential in the phytoremediation of HM-contaminated soils. 相似文献
20.
Summary The effect of Ca on the absorption and translocation of Mn, Zn and Cd in excised barley roots was studied using a multi-compartment
transport box technique. A radioisotope (54Mn,65Zn or115mCd)-labelled test solution was supplied to the apexes of excised roots and the distribution pattern in the roots was examined
in the absence or presence of Ca. Results obtained were as follows.
Addition of Ca to the test solution reduced the absorption of Mn and inhibited drastically its translocation in excised roots.
With increasing concentrations of Ca in test solutions, its inhibitory effects on the absorption and translocation of Mn became
severe.
Similar results were observed for the absorption and translocation of Zn. Ca in the test solution decreased the absorption
and inhibited drastically the translocation of Zn; as in the case of Mn, higher concentrations of Ca had severe effects on
these functions.
It was also evident that the addition of Ca to the test solution reduced the absorption of Cd at all levels of Cd concentration
(1, 10, and 100 μM). Cd absorption decreased with increasing concentrations of Ca in the test solution. However, Ca accelerated the translocation
of Cd in excised roots supplied with test solutions containing up to 10μM Cd. At 100μM Cd, addition of Ca caused a negligibly small acceleration of Cd translocation.
The accelerating effect of Ca on Cd translocation, especially “xylem exudation”, decreased markedly with the addition of 2,4-dinitrophenol,
but not with the addition of chloramphenicol or p-chloromercuribenzene sulphonic acid. When barley plants were supplied with
only CaSO4 during the entire growing period, that is, plants were not supplied with nutrient solution on the last day of this period,
Ca had no accelerating effect on Cd translocation in excised roots. 相似文献