Copper-contaminated Soil Research Articles

Growth and tolerance of Ilex paraguariensis A. St.-Hil. inoculated with ectomycorrhizal fungi in copper-contaminated soil

Copper (Cu) is one of the main heavy metals contaminating the soil. Plants have different behavior in terms of tolerance and toxicity to metals, being able to grow and produce even in soils contaminated with high concentrations. This study aimed to determine the influence of ectomycorrhizal fungi on the growth and tolerance of yerba mate plants grown in soil contaminated with Cu. The design was completely randomized in a factorial arrangement (4x6), with four possibilities of inoculum: without inoculum (control) and three ectomycorrhizal fungi (UFSC-PT116 — Pisolithus microcarpus, UFSC-PT132 — Pisolithus tinctorius and UFSC-SU118 — Suillus cothurnatus), with six Cu doses amended to the soil (0, 80, 160, 240, 320 and 400 mg kg-1 of Cu) in seven replicates. The height of the aerial part, the diameter of the lap, the dry mass of the aerial part and root system, the leaf area, the specific surface area of the roots, the contents of Cu in the aerial and radicular parts, the tolerance index, and mycorrhizal association were assessed. Inoculation of Ilex paraguariensis seedlings with ectomycorrhiza fungi UFSC-PT116, UFSC-PT132, and UFSC-SU118 mitigates the toxicity effect caused by the excess of Cu in the soil. The UFSC-PT116 isolate promoted the highest growth and tolerance of Ilex paraguariensis seedlings under the treatments. In general, the isolates promoted the reduction of Cu toxicity in Ilex paraguariensis plants, being an important alternative to remediate Cu-contaminated areas.

Эффективность высококремнистых пород в производстве экологически безопасной продукции растениеводства

The article presents the results of studying the influence of copper-contaminated soil (typical medium-loamy chernozem) on the ecological safety of grain and the yield of spring wheat when using high-silicate rock - diatomite as a detoxifier. It was found that when diatomite was introduced into soil contaminated with up to 4 MPC Cu at a dose of 5 t/ha, it completely blocked the negative impact of copper on the formation of spring wheat yield. Contamination of the soil with copper up to 10 MPC Cu was accompanied by its accumulation in the grain above the control by 8-35%. The introduction of diatomite into the soil helped to reduce its accumulation in products by 17-50%. Keywords: SOIL CONTAMINATION WITH COPPER, DIATOMITE, ENVIRONMENTALLY SAFE PRODUCTS

Phytoremediation of copper-contaminated soil by Artemisia absinthium: comparative effect of chelating agents.

Phytoremediation is a promising method for the removal of toxic trace elements, specifically of copper, from the contaminated soil in the mining regions of Armenia. Thereby, the objectives of our study were the assessment of copper accumulation capacity and phytoremediation suitability of wormwood (Artemisia absinthium L.), a potential metal hyperaccumulator, as well as the identification of the influence of some chelating agents and their combinations on copper phytoremediation effectiveness. The results of studies have shown that A. absinthium is a relatively well-adapted plant species with the ability to grow in copper-contaminated soils collected from the surroundings of Zangezur Copper and Molybdenum Combine (south-east of Armenia). The observed decrease in plant growth in contaminated soil was possible to restore by the use of ammonium nitrate. It was revealed that for the remediation of copper-contaminated soils by phytostabilisation method, A. absinthium could be grown without the application of chelating agents, as being a perennial herb, it is able to accumulate relatively high contents of copper in its root and do not transfer this metal to the above-ground part at the same time. As opposed to the phytostabilisation method, for the cleaning of copper-contaminated soils through phytoextraction method by A. absinthium, the application of chemical amendments is needed for the enhancement of copper bioavailability and for its intensive transportation to the above-ground part of the plant. Collating the effects of various chemical agents on the plant, we concluded that the growth scheme, when the application of NH4NO3, a promoter of plant growth, is combined with the joint use of citric and malic acids, can be applied as the most expedient approach for remediation of copper-contaminated soils by phytoextraction method.

Development of mycorrhizal soybean grown in copper-contaminated soil

High concentrations of copper in the soil are toxic to the development of plants and microorganisms. The aim of this study was to select arbuscular mycorrhizal fungi efficient for the development and yield of soybeangrown in copper-contaminated soil. The experiment was laid out in a completely randomized design with a 7 × 4 factorial arrangement corresponding to seven rates of copper (0, 80, 160, 240, 320, 400, and 480 mg kg-1 of soil) and four inocula (uninoculated control and three mycorrhizal fungi, namely, Acaulospora colombiana, Dentiscutata heterogama and Rhizophagus clarus), in seven replicates. Shoot height; collar diameter; number of grains per plant; shoot and root-system dry mass; leaf area; specific root surface; copper content and accumulation in the shoots, roots, and grain; chlorophyll parameters; and mycorrhizal colonization percentage were evaluated. Inoculation with the arbuscular mycorrhizal fungi Acaulospora colombiana, Dentiscutata heterogama and Rhizophagus clarus increases the phenological and physiological parameters of soybean and its yield when grown in soil contaminated with up to 480 mg kg-1 of copper applied to the soil. The Rhizophagus clarus isolate provides greater development and yield in soybean grown in soil contaminated with up to 480 mg kg-1 of copper applied to the soil, as compared with the other isolates.

Rhizobacteria Enhancing Accumulation of Copper in Contaminated-soil by Ricinus communis L

ABSTRACT In order to explore the effect of the combination of microorganisms and castor (Ricinus communis L.) in remediating copper-contaminated soil, a pot experiment was conducted to study the synergistic effect of Acinetobacter calcoaceticus, as the rhizospheric microorganisms added to siol, on the copper uptaking by castor. The results showed that after 120 days of thinning, the shoot and root biomass of castor added with A. calcoaceticus increased increased by 22.55% and 17.82%, respectively, and the copper content increased by 18.47% and 27.88%, compared with the control (without microorganism addition). The addition of the rhizobacteria could promote the synthesis of chlorophyll, especially chlorophyll a. The SOD and POD were significantly activated at the treatment group, however, which showed a downward trend with the extension of time. Furthermore, A. calcoaceticus could stimulate the secretion of malic acid, oxalic acid, and tartaric acid obviously of the plant, and accelerated the activity of urease, catalase, acid phosphatase and sucrase in the soil. Obove result indicated that the addition of microorganisms not only promoted the growth of castor seedling and increased the tolerance of castor to copper, but also strengthened the accumulation of copper in castor.

Study on Mechanical and Microscopic Properties of Nickel–Copper-Contaminated Soil Solidified by Cement, Fly Ash and Desulfurization Gypsum Under Carbonization Condition

The engineering characteristics of remediated soil are easily affected by CO2 erosion in nature. However, there are limited investigations on the mechanical and microscopic properties of heavy metal-contaminated soil. This study introduces effect of accelerated carbonization on the mechanical and microscopic properties of nickel–copper-contaminated soil, and the soil has been treated with a novel curing agent, formed by mixing cement, fly ash and desulfurization gypsum (CFG). The objective of the study is to ascertain CO2 erosion resistance of nickel–copper-contaminated soil solidified by CFG. Using unconfined compressive strength (UCS) tests, carbonization depth, X-ray diffraction, and scanning electron microscopy, the sample’s characteristics are investigated under different carbonization times and heavy metal ion concentrations. The results demonstrate that the UCS of samples of Ni0Cu0, Ni0.02, and Ni0.4 decrease with the increasing carbonization time, while that of Ni1, Cu1, and Ni1Cu1 increase initially and then decrease; in addition, when the concentration of heavy metals is lower, the effect of carbonization on UCS of samples is more significant. Moreover, the carbonization depth of samples increases with the increasing carbonization time, and the prediction model is given. Furthermore, the microscopic analysis demonstrates that calcium carbonate is the main carbonization product. The decomposition of hydrated calcium silicate gel leads to poor integrity of the structure and more pores produced in samples, which is the main reason for the decrease of the UCS in the process of carbonization. The outcomes of this investigation provide a reference for the durability in practical engineering of heavy metal-contaminated soil solidified by CFG.

Integrated biomarker responses of rice associated with grain yield in copper-contaminated soil

Copper (Cu) contamination in soil is an environmental issue that affects rice growth and development. This study investigated changes in photosynthetic capacities in combination with integrated biomarker responses at different growth stages of rice (Oryza sativa L. var. Hom Bai Toey) exposed to various concentrations of Cu. A randomized complete block design with four replications was used. Exposure to high copper concentrations of 200 Cu mg kg-1 of soil and more resulted in a marked decline in the photosynthetic efficiency of Photosystem II (Phi2) but increased yield of non-photochemical quenching (PhiNPQ) and yield of non-regulatory energy dissipation (PhiNO) at tillering and flowering stages. In addition, these concentrations induced a delay in the flowering of rice, as a consequence of stress experienced in early growth stage. Significant lipid peroxidation and leaf area reduction were observed with 400 Cu mg kg-1 treatment at flowering stage. Rice grain yield decreased significantly at copper concentrations of 200 and 400 mg kg-1. Overall, excess copper inhibited photosynthetic capacity, growth, and development of rice in the early growth stage, and synergistic effects of yield components contributed to final grain yield reduction at harvesting stage. In addition, calculated integrated biomarker response (IBR) values reflect well the severity of Cu toxicity with a decreasing order from tillering stage to harvesting stage.

Effect of Sorbent Additives to Copper-Contaminated Soils on Seed Germination and Early Growth of Grass Seedlings.

Heavy metal and metalloid-contaminated soil is a serious barrier to colonization for many plant species. The problem of the elimination of toxic waste accumulated in technogenous soils in many highly transformed regions is extremely important. Hence, another attempt was made to analyze the effect of the addition of sorbents (BCH—biochar, B—bentonite, ChM—chicken manure, OS—organo-zeolitic substrate) to contaminated copper soil on the germination and early growth of Eurasian common grass species (Agrostis capillaris, A. stolonifera, Festuca rubra and Poa pratensis), which could potentially be used in recultivation. This experiment was based on the laboratory sandwich method. Standard germination indexes, morphometry and biomass analysis were used. The percentage of germinating seeds was lower in each of the soil variants and sorbents used compared to the control. Dry mass was positively stimulated by all sorbents. The response to the addition of sorbents, expressed as the electrolyte leakage of seedlings, was different depending on the species and type of sorbent. Among all sorbents, the most positive effects on germination and growth were observed in the case of OS. Overall, the response to the addition of sorbents was different in the studied species, depending on their stage of development.

Copper uptake, physiological response, and phytoremediation potential of Brassica juncea under biochar application

Biochar can enhance the phytoremediation of copper-contaminated soils by improving soil quality and increasing plant growth. However, the impact of biochar varies with the biomass feedstock and soil condition. Our study investigated the effect of biochar from orange bagasse-OBB and coconut husk-CHB and two copper concentrations (0.17 mg kg−1-CLS soil; 100 mg kg−1- CTS soil) on plant growth, copper uptake, and physiological response of Brassica juncea. The low- and high-Cu soils were also tested without biochar. We evaluated plant biomass, plant Cu, N and P, chlorophyll content, and chlorophyll’s transient fluorescence. Plant growth was meager without biochar, indicating that the high Cu concentration was not the only limiting factor. Biochar (OBB and CHB) increased shoot mass by 300–574% and root mass by 50–2900%, and improved chlorophyll content and photosynthetic activity by 6–16%. Both biochars were efficient in the low-Cu soil as they increased plant biomass, shoot copper concentration, and translocation factor. In the high-Cu soil, both biochars increased plant biomass and copper uptake and reduced shoot copper concentration and translocation factor. The CHB and OBB removed 342% and 783% more Cu from the contaminated soil than the Control; therefore, the OBB was proven to be the best choice for phytoremediation. Novelty statement Our study showed that the orange bagasse biochar can be successfully applied for the phytoremediation of copper-contaminated soils using Brassica juncea. The orange bagasse biochar was effective regardless of the copper level in the soil, removing twice as much copper as the coconut biochar; therefore, it can speed up the process and reduce the time needed to clean up the site. Highlights Biochar significantly improved the plant’s physiological response Biochar increased plant growth and copper uptake in the contaminated soil Translocation factor was increased in the clean soil and reduced in the contaminated soil Biochar from orange bagasse is more effective than coconut husk for phytoremediation

Insights into enhanced electrokinetic remediation of copper-contaminated soil using a novel conductive membrane based on nanoparticles.

Electrokinetic remediation is a process in which a direct electric current is applied across a section of contaminated soil to remove metals. To improve the electrokinetic remediation in this study, a conductive membrane was fabricated via in situ chemical polymerization employing pyrrole and copper oxide nanoparticles. The fabricated membrane was placed in an electric field as part of the electrode structure. A physical model was constructed and filled with copper-contaminated kaolinite in the concentration of 200mg/kg. To control the pH, 0.1M citric acid and 0.01M potassium chloride were used as the electrolyte solutions. Experimental parameters such as voltage, current, pH, EC, drained flow, and copper concentration were measured. The results showed that the minimum surface resistivity of the fabricated membrane under a maximum pressure of 8.2kPa was 2.55 kΩ/m2. The experimental results demonstrated that the use of citric acid as an electrolyte was more useful to desorb the copper due to the formation of the copper-citrate complex. When employing the fabricated membrane, the copper removal increased from 13% (in CT-2) to 63% (in GM-2), while the removal of copper using potassium chloride electrolyte increased from 42% (in CT-1) to 52% (in GM-1). The highest power consumption was obtained in experiments using citric acid. Due to the higher removal efficiency of copper in GM-2, the energy utilization efficiency (β) increased and reached 29.9 near β value of GM-1 with the lowest power consumption.

Solidification/stabilization of copper-contaminated soil using phosphogypsum

Heavy metal contamination has become a major environmental concern worldwide. On the other hand, more than 300 million tons of annual worldwide production of phosphogypsum is leading to disposal and environmental problems. In view of this, an effort has been made in this investigation to evaluate the effectiveness of phosphogypsum-based stabilization/solidification technique to remediate copper-contaminated soil. Two concentrations of copper (630 mg/kg and 20,000 mg/kg) were selected on the basis of literature and were used to synthetically prepare the contaminated soils. A systematic testing program consisted of consistency limits, compaction, unconfined compressive strength, cation exchange capacity, X-ray diffraction, and scanning electron microscopy with EDAX was conducted on phosphogypsum-treated uncontaminated and contaminated soils. The UCS test results showed that 3% phosphogypsum was optimal for uncontaminated soil, which was used to treat the contaminated soils. An increase in strength was observed in uncontaminated soil with lower phosphogypsum content at all curing periods (3, 7, 14 and 28 days). Formation of copper sulfate-based minerals with good retention and diminutive leaching characteristics of copper in soil indicates the effectiveness of PG. Overall, phosphogypsum can be employed for effective treatment of copper-contaminated soils.

Does Copper Contamination Affect Soil CO2 Emissions? A Literature Review

Contaminated soils are widespread and contamination is known to impact several biotic soil processes. But it is still not clear to what extent soil contamination affects soil carbon efflux (CO2) occurring through soil microfauna respiration. Regarding the large stocks of organic carbon (Corga) stored in soils, even limited changes in the outputs fluxes may modify atmospheric CO2 concentration with important feedbacks on climate. In this study, we aimed at assessing and quantifying how soil respiration is affected by contamination. For that, we performed a quantitative review of literature focusing on 1) soil heterotrophic respiration measurements thus excluding autotrophic respiration from plants, 2) soil copper contamination, and 3) the influence of pedo-climatic parameters such as pH, clay content or the type of climate. Using a dataset of 389 data analyzed with RandomForest and linear mixed statistical models, we showed a decrease in soil CO2 emission with an increase in soil copper contamination. Specific data from ex-situ spiking experiments could be easily differentiated from the ones originated from in-situ contamination due to their sharper decrease in soil Corga mineralization. Interestingly, ex-situ spikes data provided a threshold in soil Cu contents for CO2 emissions: CO2 emission increased for inputs below 265 mgCu.kg−1 soil and decreased above this concentration. Data from long-term in-situ contaminations due to anthropogenic activities (industrialization, agriculture, … ) also displayed an impact on soil carbon mineralization, much particularly for industrial contaminations (smelter, sewage sludge, … ) with decreased in CO2 emissions when Cu contamination increased. Soil pH was identified as a significant driver of the effect of Cu on CO2 emissions, as soil C mineralization was found to be more sensitive to Cu contamination in acidic soils than in neutral or alkaline soils. Conversely the clay content and the type of climate did not significantly explain the responses in soil C mineralization. Finally, the collected data were used to propose an empirical equation quantifying how soil respiration can be affected by a Cu contamination. The decrease in soil CO2 emissions cannot be related, however, in a role of C sink as it comes together with a decrease in soil microbial biomass.

Frankobactin Metallophores Produced by Nitrogen-Fixing Frankia Actinobacteria Function in Toxic Metal Sequestration.

A series of new metallophores, referred to as frankobactins, were extracted from cultures of the symbiotic and nitrogen-fixing actinobacterium Frankia sp. CH37. Structure elucidation revealed a 2-hydroxyphenyl-substituted oxazoline core and a chain composed of five proteinogenic and nonproteinogenic amino acids, suggesting nonribosomal peptide synthesis as the biosynthetic origin. By whole-genome sequencing, bioinformatic analysis, and comparison with other Frankia strains, the genetic locus responsible for the biosynthesis was detected. Spectrophotometric titration of frankobactin with Fe(III) and Cu(II) and mass spectrometry established the 1:1 (metal:frankobactin) coordination. Uptake experiments suggested that frankobactin A1 (1) did not serve to recruit iron, but to detoxify Cu(II). As frankobactin A1 prevents the cellular entry of Cu(II), it could play a crucial role in the symbiosis of Frankia sp. and its host in the reclamation of copper-contaminated soil.

Zinc Alleviates Copper Toxicity to Lettuce and Oat in Copper-Contaminated Soils

Copper (Cu) mining operations have a global footprint and have led to contamination of soils and Cu toxicity to plants. Understanding the controls of plant Cu uptake, including competition with other metals, such as zinc (Zn), is essential for improving plant growth in Cu-contaminated soils. The objective of this study was to evaluate the capacity of Zn to alleviate the toxicity of Cu in crops grown in Cu-contaminated soils. Lettuce was grown in 27 soils with ranges of total Cu and Zn concentrations of 82–1295 mg Cu kg−1 and 86–345 mg Zn kg−1 for a period of 21 days. Oat was grown in 21 soils with the same total Cu and Zn concentration ranges for a period of 62 days. Regression analyses were used to evaluate the impact of total soil Zn on plant growth in the Cu-contaminated soils. We show for the first time that Zn alleviates Cu toxicity in lettuce and oat grown in soils. Specifically, we observed a negative (toxicity) effect of total soil Cu and a positive (protective) effect of total soil Zn on shoot growth response for lettuce and oat. The effective concentration 50% (EC50) of Cu/Zn mass ratio was 7.0 ± 1.8 for lettuce shoot length and 5.9 ± 1.0 for oat shoot weight. These results indicate that the previously demonstrated efficacy of Zn in mitigating Cu phytotoxicity in hydroponic systems can extend to more complex soil systems. Further research should be done to evaluate specific Zn amendments for restoring vegetative growth in Cu-contaminated soils.

Response of wheat grown on copper-contaminated soil to soil silicon fertilisation

Response of wheat grown on copper-contaminated soil to soil silicon fertilisation

Tolerance and phytoremediation potential of grass species native to South American grasslands to copper-contaminated soils

Grass species native to South American can have mechanisms to tolerate copper (Cu) excess, which improves their use to phytoremediate Cu-contaminated soils . The aims of the present study are to assess the tolerance of grass species native to South American grasslands to copper-contaminated soils, as well as their adaptive responses under high Cu-stressed condition and to identify native grass species presenting the highest potential to be used for phytoremediation purposes. Soil samples were air-dried and their acidity, phosphorus and potassium levels were corrected, and the samples were incubated. Three Cu levels were used in the experiment: natural (Dose 0), with added of 40 mg kg−1 of Cu and with added of 80 mg kg−1 of Cu. Three Axonopus affinis, Paspalum notatum and Paspalum plicatulum seedlings were transferred to 5-L pots filled with soil in August and grown for 121 days. Soil solution was collected during cultivation with the aid of Rhizon lysimeters. Main concentrations of cations and anions, dissolved organic carbon and pH in the soil solution were analyzed and the ionic speciation was carried out. Cu toxicity impaired the growth of grass species native to South America, since Cu excess led to both changes in root morphology and nutritional unbalance. Among all assessed native species, Paspalum plicatulum was the one presenting the greatest potential to phytostabilize in Cu-contaminated soils, since it mainly accumulates Cu absorbed in the roots; therefore, its intercropping with grapevines is can be beneficial in Cu-contaminated soils.

A converging subset of soil bacterial taxa is permissive to the IncP-1 plasmid pKJK5 across a range of soil copper contamination.

Stressors like metals or antibiotics can affect bacterial community permissiveness for plasmid uptake, but there is little knowledge about long-term effects of such stressors on the evolution of community permissiveness. We assessed the effect of more than 90 years of soil Cu contamination on bacterial community permissiveness (i.e. uptake ability) toward a gfp-tagged IncP-1 plasmid (pKJK5) introduced via an Escherichia coli donor. Plasmid transfer events from the donor to the recipient soil bacterial community were quantified and transconjugants were subsequently isolated by fluorescence activated cell sorting and identified by 16S rRNA gene amplicon sequencing. Transfer frequency of plasmid pKJK5 was reduced in bacterial communities extracted from highly Cu contaminated (4526mg kg-1) soil compared to corresponding communities extracted from moderately (458mg kg-1) Cu contaminated soil and a low Cu reference soil (15mg kg-1). The taxonomic composition of the transconjugal pools showed remarkable similarities irrespective of the degree of soil Cu contamination and despite contrasting compositions of the extracted recipient communities and the original soil communities. Permissiveness assessed at the level of individual operational taxonomic units (OTUs; 16S rRNA gene 97% sequence similarity threshold) was only slightly affected by soil Cu level and high replicate variability of OTU-level permissiveness indicated a role of stochastic events in IncP-1 plasmid transfer or strain-to-strain permissiveness variability.

Mechanical behavior of copper-contaminated soil solidified/stabilized with carbide slag and metakaolin

Different doses of carbide slag and metakaolin are used to solidify/stabilize copper-contaminated soil in accordance with its degree of contamination. This paper presents some experimental findings on the physical and chemical properties of the treated soil, including unconfined compressive strength, stress–strain state and pH, explained by series chemical and mineralogical reactions in the solidified/stabilized soil. Results showed that the unconfined compressive strength decreases and the failure strain increases with the copper ion concentration in the soil increasing. Additionally, the failure mode of the soil gradually changed from fragile failure to plastic failure. Increasing the amount of carbide slag favored improvements in unconfined compressive strength, yet decreased the failure strain. Furthermore, the pH of the soil decreased from 8.22 to 4.36 with the initial concentration of heavy metal in the contaminated soil increasing. High concentrations of Cu2+ react with OH− in pore solutions to form complexes like [Cu(OH)4]2– to decrease alkalinity in the soil. Additionally, under certain conditions, the reaction of carboxyl (–OH) and hydrated groups (–OH2) with Cu2+ release H+, which will also reduce the pH value in the soil. However, when the carbide slag content increased from 5 to 15%, the pH increased significantly, up to 10.5, demonstrating the beneficial effect of the industrial waste carbide slag in solidifying/stabilizing the copper-contaminated soil.

Foliar application of gibberellic acid endorsed phytoextraction of copper and alleviates oxidative stress in jute (Corchorus capsularis L.) plant grown in highly copper-contaminated soil of China.

Copper (Cu) is an abundant essential micronutrient element in various rocks and minerals and is required for a variety of metabolic processes in both prokaryotes and eukaryotes. However, excess Cu can disturb normal development by adversely affecting biochemical reactions and physiological processes in plants. The present study was conducted to explore the potential of gibberellic acid (GA3) on fibrous jute (Corchorus capsularis L.) seedlings grown on Cu mining soil obtained from Hubei Province China. Exogenous application of GA3 (10, 50, and 100 mg/L) on 60-day-old seedlings of C. capsularis which was able to grow in highly Cu-contaminated soil (2221 mg/kg) to study different morphological, physiological, and Cu uptake and accumulation in different parts of C. capsularis seedlings. According to the results, increasing concentration of GA3 (more likely 100 mg/L) alleviates Cu toxicity in C. capsularis seedlings by increasing plant growth, biomass, photosynthetic pigments, and gaseous exchange attributes. The results also showed that exogenous application of GA3 reduced oxidative stress in C. capsularis seedlings by the generation of extra reactive oxygen species (ROS). The reduction in oxidative stress in C. capsularis seedlings is because that plant has strong enzymatic antioxidants [superoxidase dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT)], which ultimately increased their activities to overcome oxidative damage in the cells/tissues. In addition to the plant growth, biomass, and photosynthesis, foliar application of GA3 also helps to increase metal (Cu) concentration in different parts of the plants when compared to 0 mg/L of application of GA3. From these findings, we can conclude that foliar application of GA3 plays a promising role in reducing ROS generation in the plant cells/tissues and increased phytoextraction of Cu in different plant parts. However, more investigation is needed on field experiments to find a combination of GA3 with a very higher concentration of Cu using fibrous C. capsularis.

Investigating the potential of different jute varieties for phytoremediation of copper-contaminated soil.

Copper (Cu), with many documented cases of Cu toxicity in agriculture lands, is becoming an increasingly common issue in and elsewhere in China. However, fibrous crop such as jute is being used as phytoremediation candidate in Cu-contaminated soils due to its huge biomass. A pot experiment was conducted using four different varieties (HT, C-3, GC, and SH) of jute grown in highly Cu-contaminated soil (2221mgkg-1), collected from Hubei Province, China. Results from this study showed that C-3 and HT were more resistant to Cu stress, while GC and SH had a serious effect due to high concentration of Cu and a significant decrease in growth and biomass. Furthermore, Cu in roots, leaves, stem core, and bast were higher in C-3 and HT compared with GC and SH. Likewise, at post-harvesting stage, maximum Cu concentration from Cu-contaminated soil was extracted by C-3 and HT while small amount was accumulated by GC and SH. The high content of malondialdehyde (MDA) in the leaves of GC and SH indicated that Cu induced oxidative damage while the antioxidative enzyme activities of superoxidase dismutase (SOD) and peroxidase (POD) were increased to scavenge reactive oxygen species (ROS) formed during oxidative stress in the plants. Conclusively, it can be identified that when grown in Cu-contaminated soil, C-3 and HT have greater ability to grow in polluted soils and possible phytoremediation materials to revoke a large amount of Cu.