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1.
The application of Pb inhibited the development of mycelia of the saprobe fungi Fusarium concolor and Trichoderma koningii and the hyphal length of the arbuscular mycorrhizal fungi (AM) Glomus mosseae and G. deserticola in vitro. The application to soil of 1500 mg kg?1 of Pb decreases the dry weight, total N, P, Mg and Fe concentration and chlorophyll content of the shoot of E. globulus no inoculated with AM fungi. However, G. deserticola increased the dry weight, total nutrient concentration and chlorophyll content of the shoot, and the percentage of AM root length colonization and the succinate dehydrogenase activity of AM mycelia of E. globulus in presence of 1500 mg kg?1 of Pb, and these increases were higher when G. deserticola was inoculated together with T. koningii. The application to soil of 3000 mg kg?1 of Pb decreased the shoot dry weight and AM colonization of E. globulus in all treatments tested. Pb was accumulated in the stem more than in the leaves of E. globulus. In presence of 1500 mg kg?1 of Pb the highest accumulation of this metal in the stem took place when E. globulus was colonized with G. deserticola. In conclusion, the possibility to increase Lead accumulation in stem is very attractive for phytoextraction function, the saprobe fungi, AM and their interaction may have a potential role in elevating phytoextraction efficiency and stimulate plant growth under adverse conditions such as lead contaminated soil.  相似文献   

2.
Cadmium (Cd) accumulation and distribution was studied in sunflower (Helianthus annuus L., public line HA‐89) plant. From an uncontaminated sandy loam brown forest soil with 162 μg kg‐1 HNO3/H2O2 extractable Cd the HA‐89 sunflower public line accumulated 114 ug kg‐1 Cd in its kernels under open field conditions. This value is rather low as compared to data found by others. Sandy loam brown forest soil was treated with 0, 1 or 10 mg kg‐1 of Cd to study the interaction of this heavy metal with young sunflower plants in a greenhouse pot experiment. The fresh weight and dry matter accumulation of sunflower plant organs (roots, shoots, leaves or heads) was unaffected by cadmium treatment of soil. The nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), iron (Fe), manganese (Mn), or zinc (Zn) uptake of sunflower plant organs was not influenced by lower or higher Cd‐doses, except sunflower heads where 10 mg kg‐1 of Cd treatment of soil significantly reduced the uptake of Ca, Fe, and Mn. Although Cd reduced the Zn uptake of roots, its rate was statistically not significant. Cadmium was accumulated prevalently in roots (1.21 mg kg‐1,4.97 mg kg‐1, or 13.69 mg kg‐1 depending on Cd‐dose), and its concentration increased also in shoots or leaves. In spite of the short interaction time, elevated concentrations of cadmium (0.78 mg kg‐1, 1.34 mg kg‐1, or 3.02 mg kg‐1 depending on Cd‐dose) were detected in just emerged generative organs (heads) of young sunflower plants.  相似文献   

3.
Several anthropogenic activities lead to the production of substantial amounts of aqueous effluents that contain various toxic trace and heavy metals and which pose potential threats to the wild habitat of wetlands. As a part of the remediation of heavy metals, it is necessary to identify some aquatic hyperaccumulator plants. To this end, a greenhouse study was conducted to investigate the phytotoxicity resulting from lead (Pb) and its accumulation in selected plant species. Lead was added from low to very high levels in a swell–shrink clayey soil (Typic Haplustert). Seven levels of Pb (0, 50, 100 200, 400, 600, and 800 mg kg–1 soil) were applied. Typha angustifolia L. of Typhaceae and Behaya plant (Ipomoea carnea L.) of the Convolvulaceae family were taken as test plants. Lead was added at high and low concentrations to determine whether an increase in concentration would Pb to an increased toxicity to the plants. Recorded weight of the Typha crop was reduced (6%) at 600 mg Pb kg–1 soil, and at greater doses of Pb, the dry-matter yield was inhibited considerably. In the case of Ipomoea, no growth retardation from Pb was observed. Most Pb accumulated in roots and then was transported to shoots. The Typha angustifolia L. and Ipomoea carnea L. plants show promise for the removal of Pb from contaminated wastewater because they can accumulate high concentrations of Pb in roots (1200 and 1500 mg Pb kg–1 respectively) and shoots (275 and 425 mg Pb kg–1 respectively). Lead uptake by both the plants increased with the increasing doses of Pb (50 to 800 mg kg–1 soil). Physiological parameters such as photosynthesis, respiration, chlorophyll content, and different enzyme activities including nitrate reductase (NR), peroxidase (POD), and succinate dehydrogenase (SD) were also studied for the evaluation of these plant species. In Typha plants, at greater doses of Pb, the rate of photosynthesis and chlorophyll content decreased whereas POD and SD activities increased to combat oxidative stress.  相似文献   

4.
Chickpea plants were grown in arsenic (As)–contaminated soils (5 mg kg?1 of dry soil) and investigated for As uptake, distribution, and effects on growth, yield, and quality of seeds. The roots accumulated the greatest As (7 mg kg?1 dry weight), followed by stem (4.8 mg), leaves (4.0 mg), and seeds (0.7 mg). Arsenic inhibited the growth of the roots and shoots (as dry weight) by 65% and 60%, respectively, over controls. The shoot/root ratio declined from 4.3 in the control to 3.5 in As-treated plants. The seed yield (g) and number of pods plant?1 decreased by 66 and 53%, respectively, over controls. A marked increase in membrane damage coupled with reduction in chlorophyll and relative leaf water content occurred in As-treated plants. The contaminated plants showed 34% and 25% decrease over control in sucrose content in their leaves and seeds, respectively. The accumulation of seed reserves such as starch, proteins, sugars, and minerals was inhibited significantly due to As-treated plants. Storage proteins such as albumins, globulins, glutelins and prolamins decreased significantly with larger effect on glutelins. The contents of minerals such as calcium (Ca), phosphorus (P), and iron (Fe) declined greatly in the seeds of As-treated plants. The accumulation of amino acids such as lysine, methionine?+?cystine, phenylalanine?+?tyrosine, proline, threonine, tryptophan, and valine was inhibited significantly in the seeds of As-applied plants compared to the control. The findings indicated that As application markedly reduced the quality of the chickpea seeds, especially in terms of proteins and minerals.  相似文献   

5.
The phytoremediation potential for Pb of Buddleja asiatica (a wild species) and a closely related cultivated species, B. paniculata, was investigated by means of field survey, hydroponic and pot experiments, and field trial experiments. Field surveys showed that B. asiatica had an extraordinary accumulation capacity and tolerance for Pb. Plants grown in soil with 2,369.8–206,152 mg kg?1 total Pb accumulated 1,835.5–4,335.8 mg kg?1 Pb in their shoots. Under hydroponic conditions (10, 20 mg l?1 Pb), both B. asiatica and B. paniculata showed unusually high concentrations of Pb in their roots (12,133–21,667 mg kg?1) and increased biomass production. A pot experiment in a greenhouse without any soil amendments was conducted on three different soils with various Pb contents (10,652, 31,304, 89,083 mg kg?1) for 3 months. The results showed that both species of Buddleja had an increase in the biomass similar to the control plants. There was a slight decrease in survival rates of plants grown in soil with 89,083 mg kg?1 Pb content. A field trial experiment was conducted for 6 months at three sites around the Pb mine area in which plants were provided with Osmocote fertilizer. Both Buddleja species showed 100% survival, increased biomass production and phytoextraction capacity (TF 1.1–2.3) when grown in soil with Pb content of 94,584–101,405 mg kg?1. Plants accumulated 2,273–3,675 mg kg?1 Pb in their shoots. The results suggest these Buddleja plants are suitable for use in the phytoremediation of Pb-contaminated soil.  相似文献   

6.
ABSTRACT

Cadmium (Cd) and lead (Pb) are toxic trace elements which are not essential for plants but can be easily taken up by roots and accumulated in various organs, and cause irreversible damages to plants. A pot experiment was carried out to investigate the individual and combined effects of Cd (0, 10, 20 mg kg?1) and Pb (0, 500, 1000 mg kg?1) level in a calcareous soil on the status of mineral nutrients, including K, P, Ca, Mg, S, Fe, Mn, Cu, and Zn, in alfalfa (Medicago sativa L.) plants. Soil Pb level considerably (P ≤ 0.05) affected the concentrations of more elements in plants than soil Cd level did, and there were combined effects of soil Cd level and Pb level on the concentrations of some nutrients (Ca, Mg, and Cu) in plants. The effects of soil Cd level and Pb level on plant nutrient concentrations varied among plant parts. Cd and Pb contamination did not considerably affect the exudation of carboxylates in the rhizosphere. An increase in rhizosphere pH and exudation of significant amounts of carboxylates (especially oxalate) in the rhizosphere might contribute to the exclusion and detoxification of Cd and Pb. Neither shoot dry mass nor root dry mass was significantly influenced by soil Cd level, but both of them were considerably reduced (by up to 25% and 45% on average for shoot dry mass and root dry mass, respectively) by increasing soil Pb level. The interaction between soil Cd level and Pb level was significant for root dry mass, but not significant for shoot dry mass. The results indicate that alfalfa is tolerant to Cd and Pb stress, and it is promising to grow alfalfa for phytostabilization of Cd and Pb on calcareous soils contaminated with Cd and Pb.  相似文献   

7.
A greenhouse experiment was designed to determine the cadmium (Cd) and lead (Pb) distribution and accumulation in parsley plants grown on soil amended with Cd and Pb. The soil was amended with 0, 5, 10 20, 40, 60, 80, and 100 mg Cd kg?1 in the form of cadmium nitrate [Cd(NO3)2] and 0, 5, 10, 50 and 100 mg Pb kg?1 in the form of lead nitrate [Pb(NO3)2]. The main soil properties; concentrations of the diethylenetriaminepentaacetic acid (DTPA)–extractable metals lead (Pb), Cd, copper (Cu), iron (Fe), zinc (Zn), and manganese (Mn) in soil; plant growth; and total contents of metals in shoots and roots were measured. The DTPA-extractable Cd was increased significantly by the addition of Cd. Despite the fact that Pb was not applied, its availability was significantly greater in treatments 40–100 mg Cd kg?1 compared with the control. Fresh biomass was increased significantly in treatments of 5 and 10 mg Cd kg?1 as compared to the control. Further addition of Cd reduced fresh weight but not significantly, although Cd concentration in shoots reached 26.5 mg kg?1. Although Pb was not applied with Cd, its concentration in parsley increased significantly in treatments with 60, 80, and 100 mg Cd g?1 compared with the others. Available soil Pb was increased significantly with Pb levels; nevertheless, the increase was small compared to the additions of Pb to soil. There were no significant differences in shoot and root fresh weights between treatments, although metal contents reached 20.0 mg Pb kg?1 and 16.4 mg Pb kg?1 respectively. Lead accumulation was enhanced by Pb treatments, but the positive effect on its uptake was not relative to the increase of Pb rates. Cadmium was not applied, and yet considerable uptake of Cd by control plants was evident. The interactive effects of Pb and Cd on their availability in soil and plants and their relation to other metals are also discussed.  相似文献   

8.
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   

9.
In a screen-house study, the effects of artificially contaminating the soil with lead (Pb) at levels ranging from 0 to 1500 mg kg?1 soil on the growth and uptake of Pb and micronutrients by Indian mustard [Brassica juncea (L.) Czern.] grown on a loamy sand soil (Typic Ustorthent) were investigated. The crop was grown for 60 days with adequate basal fertilization of nitrogen, phosphorus, and potassium, and dry matter was recorded. The plants were analyzed for total Pb and micronutrients, and the soil was analyzed for diethylenetriaminepentaacetic acid (DTPA)-extractable Pb. The DTPA-extractable Pb measured before sowing of Indian mustard increased consistently and significantly with increase in rates of Pb application to soil. It increased from 0.65 mg kg?1 in the control to 199.8 mg kg?1 in soil treated with 1500 mg Pb kg?1 soil. Significant reduction in the dry-matter yield of Indian mustard occurred with Pb applications of 500 mg kg?1 soil and greater. The concentration as well as uptake of Pb by Indian mustard increased significantly over control at all rates of its application. It increased from 9.4 μg pot?1 in the control to 220.6 μg pot?1 at Pb application of 1500 mg kg?1 soil. Applications of Pb to the soil decreased the concentration of micronutrients in plants, but a significant reduction occurred only for iron at rates greater than 500 mg Pb kg?1 soil. However, the uptake of iron, manganese, and copper registered a significant decline at Pb application of 500 mg kg?1 and greater and that of zinc at 750 mg kg?1 and greater. In a Typic Ustorthent soil, a DTPA-extractable Pb level of 59.5 mg kg?1 and plant content of 44.2 μg Pb g?1 dry matter was found to be the upper threshold levels of Pb for Indian mustard. This study suggests that once the soil is contaminated by Pb, it remains available in the soil for a long time, and such soils, if ingested with food crops, may be a significant source of Pb toxicity to both humans and grazing animals.  相似文献   

10.
The use of phosphorus (P) to reduce lead (Pb)bioavailability is being proposed as an alternative to excavationand disposal as a remedial technology for Pb-contaminated soilsin residential areas. The objective of this study was todetermine the influence of P sources and rates andCaCO3additions on the bioavailabilities of Pb, cadmium (Cd), and zinc(Zn) in a contaminated soil material using plants, a sequentialextraction procedure, and ion activities in equilibrium solutionas indicators. A contaminated soil containing 370 mg kg-1 Cd, 2800 mg kg-1 Pb and 29100 mg kg-1 Zn was amended ina factorial arrangement of CaCO3 (0 or 2000 mg kg-1) and P as rock phosphate or KH2PO4 at 0:1, 2:1 or 4:1P:Pb mole ratios. A pot study was conducted using sorghum-sudangrass (Sorghum bicolor L. Moench). The addition of P did not influence Pb concentrations in plant tissue and had little effect on Cd concentrations. An interaction between P source and level of P addition was found for Zn concentrations in plant tissue; concentrations increased with increasing amounts of P from KH2PO4 anddecreased with increasing amounts of P from rock phosphate. Sequential extraction results suggested a much greater reduction in Pb bioavailability from treatment withKH2PO4 than with rock phosphate and that P influencedthe fractionations of Cd and Zn. Activities of Cd2+,Pb2+, and Zn2+ in equilibrium solutions generally weredecreased by rock phosphate and increased by KH2PO4. Saturation indices suggested the addition ofKH2PO4shifted the soil equilibrium from octavite to hydroxypyromorphite, whereas solid-phase control of Cd2+ andZn2+ was not influenced by soil amendments. A soluble Psource was more effective in reducing Pb bioavailability thanrock phosphate but had variable effects on Cd and Znbioavailabilities.  相似文献   

11.
Heavy metal phytoextraction is a soil remediation technique, which makes use of plants in removing contamination from soil. The plants must thus be tolerant to heavy metals, adaptable to soil and climate characteristics, and able to take up large amounts of heavy metals. Most of the high biomass productive plants such as, maize, oat and sunflower are plants, which do not grow in cold climates or need intensive care. In this study three “weed” plants, Borago officinalis; Sinapis alba L. and Phacelia boratus were investigated for their ability to tolerate and accumulate high amounts of Cd and Pb. Pot experiments were performed with soil containing Cd and Pb at concentrations of up to 180 mg kg?1 and 2,400 mg kg?1 respectively. All three plants showed high levels of tolerance. Borago officinalis; and Sinapis alba L. accumulated 109 mg kg?1 and 123 mg kg?1 Cd, respectively at the highest Cd spiked soil concentration. Phacelia boratus reached a Cd concentration of 42 mg kg?1 at a Cd soil concentration of 100 mg kg?1. In the case of Pb, B. officinalis and S. alba L. displayed Pb concentrations of 25 mg kg?1 and 29 mg kg?1, respectively at the highest Pb spiked soil concentration. Although the Pb uptake in P. boratus reached up to 57 mg kg?1 at a Pb spiked soil concentration of 1,200 mg kg?1, it is not suitable for phytoextraction because of its too low biomass.  相似文献   

12.
Environmental concern due to plant accumulation of natural radionuclides is a major concern in uranium mining areas. To evaluate the risk associated with the transfer of radionuclides to edible plants, the uptake of 238U, 226Ra, and 210Pb by Chinese cabbage (Brassica rapa L. subsp. pekinensis (Lour.) Hanelt) grown in soils contaminated with uranium-mill tailings (UMT) was investigated. Test plants were grown under controlled conditions in substrate composed of soil and UMT in different ratios. Activity concentrations of 238U, 226Ra, and 210Pb in substrate, leaves, and roots were measured and the concentration ratios determined. Soil characteristics were determined, since they directly affect bioavailability of radionuclides. Concentration ratios of 238U, 226Ra, and 210Pb in leaves varied from 0.001 to 0.006, 0.024 to 0.172, and 0.004 to 0.011, respectively, and in roots from 0.020 to 0.126, 0.015 to 0.241, and 0.033 to 1.460, respectively. Concentrations of 238U, 226Ra, and 210Pb in leaves and roots were found to correlate with the amount of 238U, 226Ra, and 210Pb in the substrate. A higher amount of 226Ra accumulated in aboveground parts (57–877 Bq kg?1 d. m. for leaves) compared to 238U (0.6–4.7 Bq kg?1 d. m. for leaves) and 210Pb (8–53 Bq kg?1 d. m. for leaves), which were mainly stored in the roots. The relationships between the amount of radionuclides in plants and soil characteristics and their role in radionuclide uptake are discussed and critically evaluated.  相似文献   

13.
ABSTRACT

Elsholtzia splendens Naki has been identified as a copper (Cu) geobotanical indicator. In this study, the effects of Cu supply levels (control, 100, 200, 400, 600, 800, 1000, 1200 mg kg1) on the growth and Cu accumulation in E. splendens were studied in one pot experiment. The results showed that no reduction in shoot height and dry weight was noted when the plants were grown at Cu supply levels up to 1000 mg kg?1 in soil. Slight stimulation on shoot growth was noted at Cu levels ≥ 100 mg kg?1. Copper concentration in shoots and roots increased with increasing Cu levels, and reached a maximum of 1751 and 9.45 mg kg?1 (DW) at 1200 mg Cu kg?1. The amount of Cu accumulated in the roots and shoots were 313 and 22 μ g plant?1 at external Cu levels of 1000 and 800 mg kg?1, respectively. The shoot/root Cu ratios ranged from 0.005 to 0.008 and more than 92% of the total Cu taken up by E. splendens was accumulated in roots. Furthermore, Cu concentrations in roots and shoots were significant and positively correlated with total soil Cu, water, ammonium nitrate (NH4NO3), ammonium (NH4)-acetate, and ethylenediaminetetraacetic acid (EDTA) extractable Cu. These results indicate that E. splendens can considered as a Cu tolerant and accumulated plant, and root is the major part for accumulation of Cu in E. splendens.  相似文献   

14.
A soil-culture study was conducted to investigate the phytoextraction of lead (Pb) in two species of vetiver grass (Vetiveria zizanioides and V. nemoralis) irrigated with an increasing level of Pb(NO3)2 (5, 7, 9 and 11 g L-1) for 12 weeks. In a laboratory study, the removalof lead from soil was correlated with lead accumulation by roots and shoots of both species of vetiver grass. High concentration of lead (9—11 g L-1) resulted in decrease of growth, total chlorophyllcontent and biomass of V. zizanioides, while V. nemoralis died after one week of application. Toxicity symptoms (e.g., burning leaf margins, shoot die back) occurred in vetiver grass at a high concentration of lead. Based on the data V. zizanioides tolerated and accumulated the greatest amount of lead most effectively. A simulated field experiment was conducted to examine the efficiency of vetiver grass in removing lead from contaminated soil. The vetiver grasses, V. zizanioides and V. nemoralis, were grown in soil contaminated with Pb(NO3)2 (5, 7, 9, and 11 g L-1) for 3 months. The removal of lead from soil was correlated with lead accumulation by roots and shoots of both grass species. The grass roots took up more lead than the shoots. V. zizanioides could uptake more lead from soil than V. nemoralis. The effects of lead on the biomass of V. zizanioides and V. nemoralisshowed that in both species, the biomass was decreased when the lead concentration was increased. In comparison, V. zizanioidesshowed greater biomass than V. nemoralis.  相似文献   

15.
Soil contamination with heavy metals can lead to losses in agricultural yield and affect human health as the metals enter the food chain, which has become a worldwide problem. Compared with other heavy metals, lead (Pb) contamination is high because of its long persistence in soil and highly toxic effects on crop production and human health. Wheat is the world's most widely grown cereal and can be cultivated in a wide range of soils. Recently, wheat has been grown widely in northern China. The aims of the present studies are to investigate the effect of Pb on antioxidative metabolisms and chlorophyll synthesis of wheat ‘Jinan No. 17.’ Moreover, calcium ion (Ca2+) levels and bioaccumulation of Pb in the leaves of wheat were investigated. The soil was artificially contaminated with different concentrations of Pb [0, 100, 500, and 2000 Pb mg kg?1 dry weight (DW) soil as lead nitrate, Pb(NO3)2]. The catalase (CAT) activity and glutathion (GSH), chlorophyll a, chlorophyll b, and total chlorophyll contents in the leaves of wheat were analyzed with a spectrophotometer at different stages of wheat growth. Calcium levels and bioaccumulation of Pb in the leaves of wheat were studied with inductively coupled plasma sector field mass spectrometry (ICP-SF-MS). The results indicated that Pb stress can increase the content of GSH in leaves of wheat, thereby affecting the activity of CAT. Both low and high concentrations of Pb stimulated chlorophyll synthesis at early stages of wheat growth and inhibited chlorophyll synthesis at later stages of wheat growth. Furthermore, Ca and Pb in leaves of wheat increased with increasing concentrations of Pb on day 34 as determined with ICP-SF-MS.  相似文献   

16.
The effects of inoculating arbuscular mycorrhizal (AM) fungi on the growth, phosphorus (P) uptake, and yield of Welsh onion (Allium fistulosum L.) were examined under the non-sterile field condition. Welsh onion was inoculated with the AM fungus, Glomus R-10, and grown in a glasshouse for 58?days. Non-inoculated plants were grown as control. Inoculated and non-inoculated seedlings were transplanted to a field with four available soil P levels (300, 600, 1,000, and 1,500?mg P2O5?kg?1 soil) and grown for 109?days. AM fungus colonization, shoot P concentration, shoot dry weight, shoot length, and leaf sheath diameter were measured. Percentage AM fungus colonization of inoculated plants was 94% at transplant and ranged from 60% to 77% at harvest. Meanwhile, non-inoculated plants were colonized by indigenous AM fungi. Shoot length and leaf sheath diameter of inoculated plants were larger than those of non-inoculated plants grown in soil containing 300 and 600?mg P2O5?kg?1 soil. Shoot P content of inoculated plants was higher than that of non-inoculated plants grown in soil containing 300 and 600?mg P2O5?kg?1 soil. Yield (shoot dry weight) was higher for non-inoculated plants grown in soil containing 1,000 and 1,500?mg P2O5?kg?1 soil than for those grown in soil containing 300 and 600?mg?P2O5 kg?1 soil. Meanwhile, the yields of inoculated plants (200?g plant?1) grown in soils containing the four P levels were not significantly different. Yield of inoculated plants grown in soil containing 300?mg P2O5 kg?1 soil was similar to that of non-inoculated plants grown in soil containing 1,000?mg P2O5?kg?1 soil. The cost of AM fungal inoculum for inoculated plants was US$ 2,285?ha?1 and lower than the cost of superphosphate (US$ 5,659?ha?1) added to soil containing 1,000?mg P2O5 kg?1 soil for non-inoculated plants. These results indicate that the inoculation of AM fungi can achieve marketable yield of A. fistulosum under the field condition with reduced application of P fertilizer.  相似文献   

17.
Phytoextraction of Heavy Metals by Eight Plant Species in the Field   总被引：1，自引：0，他引：1  
Phytoremediation is an in situ, cost-effective potential strategy for cleanup of sites contaminated with trace metals. Selection of plant materials is an important factor for successful field phytoremediation. A field experiment was carried out to evaluate the phytoextraction abilities of six high biomass plants (Vertiveria zizanioides, Dianthus chinensis, Rumex K-1 (Rumex upatientia × R. timschmicus), Rumex crispus, and two populations of Rumex acetosa) in comparison to metal hyperaccumulators (Viola baoshanensis, Sedum alfredii). The paddy fields used in the experiment were contaminated with Pb, Zn, and Cd. Our results indicated that V. baoshanensis accumulated 28 mg kg?1 Cd and S. alfredii accumulated 6,279 mg kg?1 Zn (dry weight) in shoots, with bioconcentration factors up to 4.8 and 6.3, respectively. The resulting total extractions of V. baoshanensis and S. alfredii were 0.17 kg ha?1 for Cd and 32.7 kg ha?1 for Zn, respectively, with one harvest without any treatment. The phytoextraction rates of V. baoshanensis and S. alfredii for Cd and Zn were 0.88 and 1.15%, respectively. Among the high biomass plants, R. crispus extracted Zn and Cd of 26.8 and 0.16 kg ha?1, respectively, with one harvest without any treatment, so it could be a candidate species for phytoextraction of Cd and Zn from soil. No plants were proved to have the ability to phytoextract Pb with high efficiency.  相似文献   

18.
Summary Mature (flowering) tobacco (Nicotiana tabacum cv. PBD6, Nicotiana rustica cv. Brasilia) and maize (Zea mays cv. INRA 260) plants were grown in an acid sandy-clay soil, enriched to 5.4 mg Cd kg–1 dry weight soil with cadmium nitrate. The plants were grown in containers in the open air. No visible symptoms of Cd toxicity developed on plant shoots over the 2-month growing period. Dry-matter yields showed that while the Nicotiana spp. were unaffected by the Cd application the yield of Z. mays decreased by 21%. Cd accumulation and distribution in leaves, stems and roots were examined. In the control treatment (0.44 mg Cd kg–1 dry weight soil), plant Cd levels ranged from 0.4 to 6.8 mg kg–1 dry weight depending on plant species and plant parts. Soil Cd enrichment invariably increased the Cd concentrations in plant parts, which varied from 10.1 to 164 mg kg–1 dry weight. The maximum Cd concentrations occurred in the leaves of N. tabacum. In N. rustica 75% of the total Cd taken up by the plant was transported to the leaves, and 81% for N. tabacum irrespective of the Cd level in the soil. In contrast, the Cd concentrations in maize roots were almost five times higher than those in the leaves. More than 50% of the total Cd taken up by maize was retained in the roots at both soil Cd levels. The Cd level in N. tabacum leaves was 1.5 and 2 times higher at the low and high Cd soil level, respectively, than that in N. rustica leaves, but no significant difference was found in root Cd concentrations between the two Nicotiana spp.Cd bioavailability was calculated as the ratio of the Cd level in the control plants to that in the soil or as the ratio of the additional Cd taken up from cadmium nitrate to the amount of Cd applied. The results showed that the plant species used can be ranked in a decreasing order as follows: N. tabacum > N. rustica > Z. mays.  相似文献   

19.
Lygeum spartum, Zygophyllum fabago and Piptatherum miliaceum are typical plant species that grow in mine tailings in semiarid Mediterranean areas. The aim of this work was to investigate metal uptake of these species growing on neutral mine tailings under controlled conditions and their response to fertilizer additions. A neutral mine tailing (pH of soil solution of 7.1–7.2) with high total metal concentrations (9,100 and 5,200 mg kg?1 Zn and Pb, respectively) from Southern Spain was used. Soluble Zn and Pb were low (0.5 and <0.1 mg l?1, respectively) but the major cations and anions reached relatively high levels (e.g. 2,600 and 1,400 mg l?1 Cl and Na). Fertilization caused a significant increase of the plant weight for the three species and decreased metal accumulation with the exception of Cd. Roots accumulated much higher metal concentrations for the three plants than shoots, except Cd in L. spartum. Shoot concentrations for the three plants were 3–14 mg kg?1 Cd, 150–300 mg kg?1 Zn, 4–11 mg kg?1 Cu, and 1–10 mg kg?1 As, and 6–110 mg kg?1 Pb. The results indicate that neutral pH mine tailings present a suitable substrate for establishment of these native plants species and fertilizer favors this establishment. Metal accumulation in plants is relatively low despite high total soil concentrations.  相似文献   

20.
The objective of this work was to evaluate the affects of the application of composted biosolids on the accumulation of heavy metals (Cd, Cu, Ni, Pb and Zn) in lettuce leaves. Pots containing different proportions (0 to 100%) of composted biosolids were used to grow lettuce plants under greenhouse conditions. Dry and fresh weight, leaf area and Cd, Cu, Ni, Pb and Zn uptake were determined after harvest. It was found that the dry and fresh matter productions of the plants were significantly lower in the control treatment. The addition of composted biosolids caused a 20 and 40% increase in biomass accumulation. Cd and Pb concentrations in leaves were below detection limits (0.05 mg kg?1) in all treatments. Zn concentration in leaves increases as compost proportion decreases, ranging from 57.2 to 80.4 mg kg?1. Composted biosolids application increased the Cu and Ni plant concentrations, ranging from 5.1 to 9.8 mg Cu kg?1 and 2.3 to 3.7 mg Ni kg?1. In all treatments the proportions of heavy metals in plants were below the international standards of toxicity. The results allow us to suggest that, in short-term applications, composted biosolids could be used as soil amendment for lettuce production, without toxic effects in the chemical composition of the plant.  相似文献   

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