Different Concentrations Of Lead Research Articles

Comprehensive Assessment of Lead Bioaccumulation in Helix aspersa (Müller, 1774), Snails: A Study of Histopathological and Biochemical Impacts

Background: The snail Helixa spersa is considered a relevant bioindicator of soil pollution by metallic elements due to its resistance and accumulation capabilities. Methods: This study aims to determine the dose-response relationship between different concentrations of lead and its toxic effects on juvenile H. aspersa through a semi-static ecotoxicity test under controlled conditions. In addition, continuous monitoring of carbohydrates, lipids and proteins of the snails affected by this metal was evaluated along with a histopathological study of the hepatopancreas. Result: The two-month lead exposure in H. aspersa resulted in significant alterations in biochemical and histological parameters. Lead concentrations in the hepatopancreas and foot exhibited a dose-dependent increase, with higher levels observed in the former. Elevated lead concentrations (1000 ìg/g and 1500 ìg/g of soil) led to substantial protein increase in both organs, while even lower doses displayed considerable protein elevation in the hepatopancreas. Carbohydrate levels were significantly lower in all contaminated groups compared to controls. Increasing lead concentrations caused a reduction in lipid levels. Histological analysis revealed distinct alterations, including excretory cell hypertrophy, tubule clustering and inflammatory changes in the hepatopancreas of treated snails. Severe histological damage, including inflammatory infiltrates, cellular debris and necrosis, were observed at higher lead concentrations (1000 and 1500 ìg/g). These findings emphasize the impact of lead exposure on biochemical profiles and organ histology in H. aspersa, highlighting the potential ecological implications of heavy metal contamination.

Screening of tolerance of Atriplex vulgatissima under zinc or lead experimental conditions. An integrative perspective by using the integrated biological response index (IBRv2).

The search for plants with a high capacity to tolerate and accumulate metals is an important issue in phytoremediation. In this sense, this study was conducted in the halophyte Atriplex vulgatissima to evaluate the effects of different concentrations of lead (Pb, 50 and 100 μM) or zinc (Zn, 100 and 200 μM) on morphological, physiological, and biochemical parameters as well as the accumulation patterns of this species. The results indicated that while essential metal Zn showed high translocation from roots to shoots (TF > 1), non-essential Pb was mainly accumulated in the roots (BCF>1). Regarding shape, both metals induced slenderness of the blade, but only Zn treatment reduced leaf size. No difference in biomass production and photosynthetic parameters was found between Pb and Zn treatments. Pb treatments did not show significant differences between treatments regarding water content (WC), pigment concentration, and the activity of superoxide dismutase (SOD) and guaiacol peroxidase (GPx), but did result in a decrease in catalase activity at 100 μM Pb. On the other hand, 200 μM Zn leads to a clear reduction in WC and pigment concentrations, along with an increase in SOD and GPx activities. In addition, ascorbate peroxidase (APx) activity showed a hormesis effect at 50 μM Pb and 100 μM Zn. Malondialdehyde increased with both Pb and Zn treatments. The integrated biological index (IBRv2) indicated that 200 μM Zn was the most affected treatment (IBRv2 = 19.02) and that under the same concentrations of metals (100 μM Pb or Zn), Pb treatments presented major stress (IBRv2 = 11.55). A. vulgatissima is a metallophyte with the potential for Pb phytostabilization and Zn phytoextraction, as well as a bioindicator of these metals. Its high biomass and deep roots, combined with its halophytic traits, make it suitable for bioremediation and monitoring programs.

Chronic lead exposure prolongs the immature stages of brown-legged grain mite, Aleuroglyphus ovatus, in a long-term population study

An important aspect of environmental pollution, lead contamination is a widespread problem in several ecosystems. The present study aimed to evaluate the potential effects of low concentration lead stress on the development and reproduction of Aleuroglyphus ovatus. They were fed with artificial diet containing four different concentrations of lead (12.5, 25, 50, and 100 mg/kg). The results showed that there were both accelerating effect of lead (at low concentrations), as well as retarding effects (at high concentrations) on the development of the mite, and lead stress significantly prolonged the immature stages of A. ovatus and this inhibitory effect was greater with greater lead concentrations. The immature stages in the L group were shorter than those in the S group. In the S and L groups, the oviposition periods were significantly longer in the treatments with lower lead concentrations than in the control, while they were significantly shorter in those treatments of higher lead concentrations. Age-specific survival rate (lx) started to decline earlier in the S group, whereas there were no differences between the L group and CK. Age-specific fecundity rate (mx) peaked earlier in the S group than in CK, while mx peaked later in L1 and L2 than in CK. The rm value and net reproduction rate (R0) of treated A. ovatus decreased with increasing lead concentrations. Lower lead concentrations could promote population expansion while higher concentrations could inhibit population size. These results confirmed the developmental effect of lead stress on A. ovatus, highlighting that heavy metal contamination has negative effects on organisms in their natural environment.

Investigation of phytoextraction and tolerance capacity of Calotropis procera for the detoxification of hexavalent chromium, nickel, and lead

The aim of the present study is to reveal the phytoremediation capability of Calotropis procera in the selected region of Bandhwari landfills. Results affirmed that the excessive deposition of municipal solid waste changes the physico-chemical parameters of the soil, which may cause soil pollution. The pot experiment was set up for heavy metals (Cr, Ni, and Pb) analysis with three different concentrations (50 ppm,100 ppm, and 150 ppm). Samples were analyzed to assess the plant’s capability for phytoremediation after 42 days. In the current investigation, ICP-MS results revealed that chromium, nickel, and lead concentration is higher than the permissible limit as per WHO. Results showed that the bioaccumulation factor follows the order of Cr > Ni > Pb. The bioconcentration factor and translocation factor are 15.63 mg/kg and 11.36 mg/kg respectively for Calotropis procera and the highest among all other metal concentrations. Peroxidase activity increases with an increase in chromium ion concentration whereas comparatively less increase of peroxidases in different concentrations of lead and nickel. Peroxidase enzyme assay and photosynthetic pigment test were carried out for tolerance estimation and uptake mechanism of Calotropis procera. FTIR data revealed significant levels of chromium complexation and binding to Calotropis procera tissue via hydroxyl and carboxyl groups. Therefore, it can be concluded that Calotropis procera has the efficiency to provide an effective way to handle heavy metal pollution problems and act as an important cost-effective tool for sustainability and conservation of the environment.

The effect of lead (Pb) on the growth rates of two aquatic macrophyte species; Limnobium laevigatum (Humb & Bonpl. ex Willd) Heine and Egeria densa Planch. grown in different experimental media

Anthropogenic causes contribute to toxic pollutants in aquatic environments and heavy metal pollution. As a heavy metal, Lead (Pb), is one of the most common causes of pollution in water. Heavy metals must be removed from the aquatic environment because they adversely affect health and all living things in each environment. In this study we aimed to determine the effects of lead (Pb) exposure on the growth rates and biomass of two aquatic macrophyte species, E. densa and L. laevigatum. Plants grown in in two different experimental media. For this purpose, both plants were exposed to 3 different concentrations of lead (1 ppm, 5 ppm, 15 ppm). Samples were measured on the 1st, 4th and 7th days, and the first and last weights of the plants were compared. Bioexperiments were run in triplicate. Positive values were observed in the growth rates of both plants, except for the negative growth rates observed on the 1st day at 1 ppm and 5 ppm lead concentrations in the pond water environment. Both plants showed positive growth in 25% Hoagland medium at all concentrations and days, except for the 1 ppm lead concentration, being observed for E. densa. As a result of our study, lead exposure did not significantly alter the growth rates of E. densa and L. laevigatum in the experimental media used for short-term (up tp 7 days) durations.

Modulatory effect of Picralima Nitida on oxidative stress: Cobalt, thiol, total protein in Drosophila melanogaster exposed to lead

Drosophila melanogaster, commonly known as fruit fly, vinegar fly, is a small model organism used in the study of various disciplines. D. biochemical, neurological and physiological sim ilarities with human beings and has about 75% functional homologs of genes causing diseases in humans. Picralima nitida is a diseases in humans. Picralima nitida is a therapeutic herb used in ethnomedicine for the management of several disease conditions. Theobjective of this study is to induce oxidative stress in Drosophila melanogaster using lead and determine its effect on the levels of selected oxidative stress parameters. Determining the potential modulatory effect of Picralima nitida on selected oxidative stress parameters in lead-induced oxidative stress in Drosophila melanogaster was also known in this study. The phytochemicals of Picralima nitida, and survival rate in Drosophila melanogaster exposed to different concentrations of lead and/or Picralima nitida in meal were also studied. A total of 250 Drosophila melanogaster flies were seen in each of the 9 groups (A-I). Group A was used as the control group and was fed with normal standard meal with water only. Group B were fed with 0.25mg/dl lead acetate meal, group C were fed with 1mg/dl lead acetate meal, group D were fed with 10mg/kg Picralima nitida meal, group E were fed with 100mg/kg Picralima nitida diet, group F were fed with 0.25mg/dl lead acetate and 10mg/kg Picralima nitida diet, group G were fed with 1 mg/dl lead acetate and 10mg/kg Picralima nitida diet, group H were fed with 0.25mg/dl lead acetate 100mg/kg Picralima nitida meal and group I were fed with 1mg/dl lead acetate and 100mg/kg Picralima nitida diet. After about 5 days, flies were homogenized and the supernatant recovered were then used for the various biochemical and survival assay, Cobalt was determined with inductively coupled plasma - mass spectrometry, total protein was determined with Lowrys method and total thiols was determined with Ellman's method. The results showed that lead at various concentrations had a toxic effect on the level of oxidative stress parameters (cobalt, thiols, total protein) in Drosophila melanogaster. While Picralima nitida a medicinal plant had a modulatory effect on the level of oxidative stress parameters (Cobalt, total thiols, total protein) in lead- induced Drosophila melanogaster, although it can become toxic when taken in high concentration. All varying concentrations of lead acetate or/and Picralima nitida reduced the survival rate in the flies. From this study it could be deduced that at low concentration Picralima nitida has modulatory effect on oxidative stress.

The metabolism and detoxification effects of lead exposure on Aleurolyphus ovatus (Acari: Acaridae) via transcriptome analysis

Aleurolyphus ovatus Troupeau is one of the most predominant species of the Acaridae family worldwide. Recent reports have demonstrated that the accumulation of lead in stored grains and dietary items exceeds the required standards. However, the molecular mechanism of heavy metal stress on mites has not been reported. To understand the mechanism underlying the heavy metal response of A. ovatus, comparative transcriptome analysis was performed in this study using an Illumina high throughput mRNA sequencing (RNA-seq) platform. A. ovatus was fed on artificial diets containing two different concentrations of lead, namely, a low concentration of 12.5 mg/kg (LAO) and a high concentration of 100 mg/kg (HAO), while the mites in the control (NAO) group were not exposed to lead. A total of 44,362 unigenes, with an average length of 1547 bp, were identified. Of these, 996 unigenes were successfully annotated in seven functional databases. The number of differentially expressed genes (DEGs) in A. ovatus under different lead concentrations was compared. In NAO versus LAO group, including 310 up-regulated and 1580 down-regulated DEGs. In NAO versus HAO group, including 3928 up-regulated and 1761 down-regulated DEGs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment indicated that detoxification enzyme genes were significantly expressed in pathways, such as cytochrome P450 foreign body metabolism, glutathione metabolism and drug metabolism-cytochrome pathway. The results of gene annotation and quantitative real-time PCR showed that high concentration of lead significantly stimulated the expression of metabolic detoxification enzyme genes such as glutathione S transferase (GST) and superoxide dismutase (SOD), while low concentration inhibited their expression. This study will provide a basis for the molecular mechanism of A. ovatus in response to heavy metal lead stimulation in stored grain.

Regulation of three subtypes of SOD gene in Aleuroglyphus ovatus (Acari: Acaridae) under lead stress

Superoxide dismutase (SOD) is an important enzyme that acts as the first line of protection in the mite antioxidant defense system and involves in eliminating reactive oxygen species (ROS) under harsh environmental conditions. Lead pollution is becoming increasingly serious and poses a serious hazard to the health and survival and reproduction of organisms. Nevertheless, the SOD gene family was yet to be reported in stored grain pest mite (Aleuroglyphus ovatus). In the present study, A. ovatus was reared on artificial diets treated with different concentrations of lead (12.5, 25, 50 and 100 mg/kg); the treatment fed on artificial diet without lead was marked as the control group (CK). Then three different subtypes of SOD were cloned, including AoSOD1 (Cu-ZnSOD), AoSOD2 and AoSOD3 (MnSOD). Enzyme activity of the egg stage was the lowest, and that of the protonymph stage was the highest. The enzyme activity of A. ovatus increased initially before dropping with increasing lead concentration, nevertheless, it was still substantially higher than that in CK. The analysis of SOD enzyme activity specified that it was higher at 25 mg/kg lead in each mite stage compared to other concentration groups. All three genes were up-regulated and thereafter reduced in the embryonic stage, according to an examination of mRNA expression levels; tritonymphs, in particular, attained the highest level. The expression level of the SOD genes also changed with lead concentration. It increased after an initial decline trend with increasing lead concentration, and then peaked in the 100 mg/kg lead group, which were 3.1 times (AoSOD1), 4.1 times (AoSOD2), and 2.3 times (AoSOD3) the control group, respectively. In this study, three AoSOD genes had developmental stage-specific mRNA expressions, and the expression of SOD enzyme activity was encouraged by the higher lead concentration, and the mRNA expression level of the AoSODs genes was not synchronized with the enzyme activity.

IMPACT OF SALT AND METALLIC STRESS ON THE SODIUM AND POTASSIUM UPTAKE BY THE VICIA FABA L. PLANTS

Environmental stresses, in particular salinity and heavy metal pollution, constitute a real problem menacing our ecosystems with detrimental effects on crop production and biodiversity. The present work aims to study the combined effect of salt stress by different concentrations of sodium chloride "NaCl" (0, 100, 200 meq) and metallic stress by different concentrations of lead "Pb(NO3 )2" (0, 1000, 3000, 5000 ppm) on the sodium and potassium contents variations of the aerial and underground parts of Vicia faba L. plants. The results obtained show that increased salinity causes an important accumulation of sodium in Vicia faba L. plants; with preferential sequestration in the roots. However, potassium compartmentalizes in the plant leaves studied with decreasing levels in response to high concentrations of sodium chloride and lead in the culture medium.

A Physiological behavior and tolerance of Lactuca sativa to lead nitrate and silver nitrate heavy metals.

This study goal to evaluate the effects of different concentrations of lead (Pb) and silver (Ag) on germination, initial growth and anatomical alterations of Lactuca sativa L. Plants use various mechanisms to reduce the impacts caused by anthropic action, such as xenobiotic elements of soils and water contaminated by heavy metals. These metals were supplied as lead nitrate and silver nitrate and the following treatments were established: control for both metals, maximum dose of heavy metals, for arable soils, allowed by the National Council of the Environment (Ag = 25 mg. Kg-1, Pb = 180 mg. Kg-1), double (Ag = 50 mg. Kg-1, Pb = 360 mg. Kg-1) and triple (Ag = 75 mg. Kg-1, Pb = 540 mg. Kg -1) of this dosage. Vigor and germination tests of the seeds and possible anatomical changes in the leaves and roots of lettuce plants were performed. The species showed a high capacity to germinate under Pb and Ag stress, and the germination was never completely inhibited; however, the germination decreased with increasing Pb concentrations, but not under Ag stress. The use of increasing doses of metals reduced seed vigor and increased chlorophyll content. An increase in biomass was also observed in plants from treatments submitted to Pb. The phytotoxic effects of metals were more pronounced at 15 days after sowing. Anatomically, L. sativa was influenced by metal concentrations, and had a reduction of up to 79.9% in root epidermis thickness at the highest Pb concentration, although some structures did not suffer significant changes. The results suggest that L. sativa presents tolerance to high concentrations of heavy metals, showing possible mechanisms to overcome the stress caused by these metals. In this research lettuce possibly used the mechanism of exclusion of metals retaining Pb and Ag in the roots preserving the photosynthetic apparatus in the aerial part of the plants. In general, the chemical element Pb was more toxic than Ag, in these experimental conditions.

Lead removal from soil by phytoremediation method

Many control approaches are used today to prevent the contamination of soils with heavy metals and to remove pollution. One of these approaches is phytoremediation for the on-site treatment of pollutants. In phytoremediation, hyperaccumulator plants are used, which absorb heavy metals, accumulate at high levels in their tissues, and neutralize them after various processes. It was aimed to determine the effects of heavy metals on plant growth and the heavy metal accumulation capacity of plants in this study. Using the phytoremediation method, the growth process of the canola plant and its lead removal capacity from the soil were investigated. The study was carried out in 3 replicates by watering the plants only with tap water and tap water containing different concentrations of lead in greenhouse conditions. The prepared soil mixture was placed in pots as 2000 g pot-1. The sown seeds were germinated using tap water in the plant growing room and the water requirement of the plants was met with tap water containing a certain concentration of lead during the next growing period. Plants were harvested at the end of the 3 month growth period. The plants irrigated with the lead solution were compared only with the plants irrigated with tap water, and the elongation amounts of root and stem lengths were determined. Plant samples with dry weights determined were burned with certain chemicals using the microwave method, and then the amount of lead in the plants was measured with the ICP-MS device.

Model-based Application for Adsorption of Lead (II) from Aqueous Solution using Low-cost Jute Stick Derived Activated Carbon

Background: Removal of lead (II) ions from supply water using an inexpensive adsorbent is essential. It is recommended that low-cost adsorbents are developed to effectively remove lead (II) ions from aqueous solutions. The aim of the study is to develop and validate models for predicting the performance of carboxylated jute stick derived activated carbon (JSAC-COOH) in removing lead (II) ions from aqueous solution, which can assist the water supply authorities in supplying lead (II) free drinking water to the communities at a low-cost. Methods: Controlled laboratory experiments were conducted following the statistical “Design of Experiments” through varying the factors affecting the performance of JSAC-COOH in removing lead (II) ions. The performance of JSACCOOH was investigated for different concentrations of lead (II) ions (range: 50 - 500 mg/L) at variable experimental conditions (temperature: 15°C and 27°C; pH: 4.0 and 7.0) and time (1, 10, 30 and 60 min). Several models (Linear and non-linear) were investigated and validated for predicting the concentrations of lead (II) ions in aqueous solution. Results: The prepared JSAC-COOH had a surface area of 615.3 m2 /g. In 60 min, up to 99.8% removal of lead (II) ions was achieved. Few models showed very good to excellent predictive capabilities with coefficients of determination in the range of 0.85–0.95. The model validation experiments showed the correlation coefficients in the range of 0.84 – 0.98. Conclusion: The models have the capabilities to reasonably predict the final concentrations of lead (II) ions, which can be used in controlling the effluent lead (II) ion concentrations. The proposed adsorbent is likely to be low-cost as it was developed using the commonly available agricultural byproduct.

Evidences for antioxidant response and biosorption potential of Bacillus simplex strain 115 against lead.

In this study, we investigated effects of lead on growth response and antioxidant defense protection in a new identified strain isolated from a soil, in the rhizosphere of Sainfoin Hedysarum coronarium L. Different concentrations of lead (0, 0.2, 1.5 and 3g L-1) added to Bacillus simplex strain 115 cultures surprisingly did not inhibit its growth. However, a resulting oxidative stress as attested by overproduction of H2O2 (+ 6.2 fold) and malondialdehyde (+ 2.3 fold) concomitantly to the enhancement of proteins carbonylation (+ 221%) and lipoxygenase activity (+ 59%) was observed in presence of 3g L-1 of lead. Intrinsic antioxidant defenses were revealed by the coupled up-regulation of catalase (+ 416%) and superoxide dismutase (+ 4 fold) activities, with a more important Fe-SOD increase in comparison to the other isoforms. Bioaccumulation assays showed both intracellular and extracellular lead accumulation. Biosorption was confirmed as a particularly lead resistance mechanism for Bacillus simplex strain 115 as the metal sequestration in cell wall accounted for 88.5% to 98.5% of the total endogenous metal accumulation. Potentiality of this new isolated microorganism as a biotechnological tool for agricultural soil lead bioremediation was thus proposed.

Effect of lead in the aerobic decomposition of Myriophyllum aquaticum (Vellozo) Verdecourt

Lead is a toxic element that has been used since early times and is still employed today in several industrial processes. Events as the collapse of the Fundão dam in Bento Rodrigues, district of Mariana (MG) on November 2015, significantly increase concentrations of metals above-recommended levels, including lead. In this context, this study aims to evaluate the impact of lead in the cycling rate of organic matter in the aquatic environment. Thus, the rates of aerobic decomposition of Myriophyllum aquaticum (Vell.) Verdec at different concentrations of lead (5.0, 10.0, 20.0 and 30.0 mg L-1) were measured, analyzing the dissolved oxygen consumption. Decomposition chambers filled with samples of water and M. aquaticum were incubated at 20° C in the dark for 80 days and periodically had the oxygen concentrations determined by polarography, when the concentrations were less than 2 mg L-1, the incubations were re-aerated. At the lowest concentrations (5.0 and 10.0 mg L-1) of lead the mineralization was lower, however, the reaction coefficients and the amount of oxygen consumed were equivalent to the control. At the highest concentrations (20.0 and 30.0 mg L-1) the mineralization was increased, with the reduction of reaction coefficients and higher oxygen consumption.

Physical properties of Pb-doped CuS nanostructures for optoelectronic applications

The present study was conducted to investigate the effects of different concentrations of lead (Pb) atoms on the physical properties of copper sulfide (CuS) nanostructures for optoelectronic applications. CuS nanostructures were grown using sonochemical method. The X-ray diffraction (XRD) patterns indicated polycrystalline phase formation of hexagonal CuS; therefore calculations through different methods demonstrated the increase in crystallite sizes with the addition of Pb concentrations. Field emission scanning electron microscopy (FESEM) images also revealed the growth of disk-like structures in nanometer dimensions, whose average size decreased by adding dopants. Optical analysis also showed an increase in the absorption and emission intensity of the doped samples compared to the un-doped sample. Photocatalytic degradation experiments for methyl orange (MO) pigments and electrical tests also showed improved optoelectronic performance of CuS nanostructures in the presence of Pb atoms in its structure. The current-voltage result was also plotted at different temperatures; it changed from nonlinear at low temperatures to linear at high temperatures. In addition, optoelectronic characterization implied the thermal dependence of the optoelectronics properties of CuS nanostructures to crystalline defects CuS. Ultimately, the hydrophilicity and hydrophobicity of un- and Pb-doped nanostructures were also investigated.

Determination of lead concentrations in the soils of Setif City, Eastern Algeria

This study describes the determination of lead and pH in Setif soils. Soil samples from the town of Setif were taken from a total of 100 subsurface soils, systematically sampled (regular 1 × 1 km grid). The lead concentration was determined by atomic absorption and the average lead concentrations ranged from 24 to 384 mg kg−1. The distribution of the different concentrations of lead and iso-concentration was distributed on the map of the exchange site with Arc GIS software. Compared with their local soil background values, higher concentrations of Pb were observed to different extents. The distribution of Pb concentrations has been explained by urban traffic.

Haemotoxic Assessment of Differential Leucocyte Counts (DLC) in Fresh Water Teleost, Heteropneustes fossilis Exposed to Lead

Fish blood is being used for assessing the health of the fish to changing environmental conditions due to heavy metals which are regularly released by anthropogenic activities. This study assesses the effects of lead (Pb) on the Differential Leucocyte Counts (DLC) of fresh water teleost Heteropneustes fossilis. The acclimatized fish were exposed to different concentrations of lead [2.25ppm (Group B), 2.65ppm (Group C), and 2.85ppm (Group D)] and the values were compared with the control (Group A). The time interval of examination was 7, 14, 21 and 28 days post exposure. DLC showed changes in small lymphocytes resulting in the fall of 41% to 31% at 2.65 ppm of Pb during 28 days of exposure period. The large lymphocyte counts also decreased of 39% to 27% at maximum concentration and maximum exposure period (2.85 ppm Pb; 28 days). The neutrophils increased (14%) to maximum (26%) at 2.65 ppm of Pb during 28 days exposure period. The monocyte counts increased 3% to 7% during 7 and 28 days exposure period at 2.65 ppm of Pb. The counts of eosinophils increased against the toxicity of lead from 2% to 6% at maximum concentration (2.85 ppm) during 14 and 28 days exposure period. Basophils increased (1%) to 3% at 2.65 ppm of Pb at 28 days exposure period. Our studies indicated that exposure to lead results in altered leucocyte counts.

Effect of lead treatment on the stipe and leaflet anatomy of Pteris vittata and Pityrogramma calomelanos (Pteridaceae: fern)

The effect of various concentrations of Lead on stipe and leaflet anatomy of Pteris vittata and Pityrogramma calomelanos were investigated. Fernlets were transplanted into 5 kg pots of soil pre-treated with five different concentrations of Lead, adequately watered and arranged in a complete randomized design in the screen house. Pots with no Lead treatment served as control. At twelve weeks after planting, plants were carefully removed, washed and taken to the laboratory. Anatomical sections of leaflets and stipe of each of the treatments were carried out with a sledge microtome (10-15 μm). Microscopic observations of structures were made after staining the sections. In Pteris vittata, the thickness of the cuticle of the stipe increased with increasing Lead concentrations but the reverse of this was observed in Pityrogamma calomelanos. There was also significant reduction of epidermal and mesophyll cell area of both species with increasing Lead concentrations. It can be concluded from this study that P. vittata has a higher tolerance level to Lead than Pityrogramma calomelanos.
 Key words: Anatomy, Cuticle thickness, Ferns, Lead, Pteridaceae.

AQUATIC PLANT (HYDRILLA VERTICILLATA) ROLES IN BIOACCUMULATION OF HEAVY METALS

The current study was aimed to test the ability of Hydrilla verticillata plant ability to accumulated of cadmium and lead in its tissues. The plant was treated with different concentrations of cadmium (1,2,4,8) ppm and lead (0.5,5,10,20) ppm for 21 days'. The concentration of metals was measured in plant and water, Bioaccumulation factor and removal ratio were also measured during days (1,7,14,21), as well as measured biomass and length of the plant were measured at the end of the experiment. The results were shown that the highest cadmium and lead removal rate were (77, 88) % at concentration (4, 10) ppm during (21, 7) days, respectively, also the bioaccumulation factor (BCF) of the two metals were (21639 and 45467) at concentrations (4 and 0.5) ppm during the 21st day of the experiment respectively. The biomass of plant in treated aquarium with different concentrations of cadmium showed a decrease during the experimental days, while increased in biomass of plant treated aquarium with different concentrations of lead. The length rate of the plant was significantly reduced in the plant that treated with cadmium but significant increase in plant treated with lead compared to the control.

Interaction of lead and cadmium on growth and leaf morphophysiological characteristics of European hackberry (Celtis australis) seedlings

BackgroundIn the present study, different concentrations of lead (factor A; 0, 15, and 30 mg L −1) and cadmium (factor B; 0 and 5 mg L −1) were applied via irrigation water during 6 months to evaluate their effects on growth of European hackberry (Celtis australis L.) plants. The experiment was arranged in factorial with completely randomized design and four replications under greenhouse conditions.ResultsApplication of 5 mg L −1 Cd or the lead levels (15 and 30 mg L −1) significantly reduced new shoot growth, plant leaf area, SPAD value, leaf water conductance and leaf photosynthesis, whereas significant increase in number of chlorotic and necrotic leaves, leaf transpiration rate, leaf proline and soluble sugars was observed. Higher reduction in new shoot growth and leaf water conductance and higher increase in leaf soluble sugars and proline was observed over the interaction of 5 mg L −1 Cd and 30 mg L −1 Pb. The highest soluble sugars and proline were in Pb30Cd5 (a3b2) treatment. Leaf Pb or Cd concentration was increased following their treatment. Application of cadmium significantly reduced leaf Pb, and similarly leaf Cd was significantly reduced by application of lead at both levels compared to untreated plants.ConclusionThe results showed that the hackberry growth was influenced by positive and negative interactions of Pb and Cd applied in irrigation water. The extent of growth reduction indicates that hackberry represents a relatively tolerant ornamental tree to high Pb and Cd levels.