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Deng S, Zhang X, Zhu Y, Zhuo R. Recent advances in phyto-combined remediation of heavy metal pollution in soil. Biotechnol Adv 2024; 72:108337. [PMID: 38460740 DOI: 10.1016/j.biotechadv.2024.108337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 11/14/2023] [Accepted: 03/05/2024] [Indexed: 03/11/2024]
Abstract
The global industrialization and modernization have witnessed a rapid progress made in agricultural production, along with the issue of soil heavy metal (HM) pollution, which has posed severe threats to soil quality, crop yield, and human health. Phytoremediation, as an alternative to physical and chemical methods, offers a more cost-effective, eco-friendly, and aesthetically appealing means for in-situ remediation. Despite its advantages, traditional phytoremediation faces challenges, including variable soil physicochemical properties, the bioavailability of HMs, and the slow growth and limited biomass of plants used for remediation. This study presents a critical overview of the predominant plant-based HM remediation strategies. It expounds upon the mechanisms of plant absorption, translocation, accumulation, and detoxification of HMs. Moreover, the advancements and practical applications of phyto-combined remediation strategies, such as the addition of exogenous substances, genetic modification of plants, enhancement by rhizosphere microorganisms, and intensification of agricultural technologies, are synthesized. In addition, this paper also emphasizes the economic and practical feasibility of some strategies, proposing solutions to extant challenges in traditional phytoremediation. It advocates for the development of cost-effective, minimally polluting, and biocompatible exogenous substances, along with the careful selection and application of hyperaccumulating plants. We further delineate specific future research avenues, such as refining genetic engineering techniques to avoid adverse impacts on plant growth and the ecosystem, and tailoring phyto-combined strategies to diverse soil types and HM pollutants. These proposed directions aim to enhance the practical application of phytoremediation and its integration into a broader remediation framework, thereby addressing the urgent need for sustainable soil decontamination and protection of ecological and human health.
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Affiliation(s)
- Shaoxiong Deng
- Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, PR China
| | - Xuan Zhang
- State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Changsha 410004, PR China
| | - Yonghua Zhu
- Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, PR China
| | - Rui Zhuo
- Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, PR China; Hunan Provincial Certified Enterprise Technology Center, Hunan Xiangjiao Liquor Industry Co., Ltd., Shaoyang 422000, PR China.
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Xin J, Liu Y, Liu J, Tian R. Colonization and phytoremediation potential for Miscanthus sacchariflorus in copper tailings. ENVIRONMENTAL TECHNOLOGY 2024; 45:532-543. [PMID: 35980148 DOI: 10.1080/09593330.2022.2114858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
A pot experiment was conducted to explore the effects of copper (Cu) tailings with various proportions in the substrate on seed germination and morphological traits of the plant. Concurrently, to identify the adaptive and tolerance strategies of the plant to Cu tailings, the uptake and accumulation of the plant to heavy metals, variations in soil enzymatic activities, and metal speciation in the blank, rhizospheric, and non-rhizospheric soils were estimated. Cu tailings at 25% proportion in the substrate exerted no significant negative effects on seed germination and seedling growth. However, Cu tailings at higher proportions (≧50%) inhibited seed germination and disturbed the plant physiological metabolism and growth. More biomass allocated to the plant roots could contribute to more heavy metals being immobilized, arresting their translocation from roots to shoots. This was accepted as a crucial defense mechanism for the plant against heavy metal co-contamination. The plant can improve the biological properties of Cu tailings in terms of enhanced invertase and phosphatase activities. And in turn, this can effectively alleviate heavy metal phytotoxicity. Simultaneously, it markedly decreased exchangeable Cu and Zn content in the rhizosphere in 25% Cu tailings treatments. In 50% Cu tailings treatment, no differences were observed in Zn speciation between rhizosphere and non-rhizosphere soils. In 75% Cu tailings, compared to the non-rhizosphere, an obvious reduction in exchangeable Cu in rhizosphere occurred, while an opposite tendency was demonstrated in carbonate-bound Zn. The plant could successfully colonize in Cu tailings, and represent a phytoremediation potential in Cu tailings.
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Affiliation(s)
- Jianpan Xin
- College of Landscape Architecture, Nanjing Forestry University, Nanjing, People's Republic of China
| | - Yali Liu
- College of Landscape Architecture, Nanjing Forestry University, Nanjing, People's Republic of China
| | - Jiefeng Liu
- College of Landscape Architecture, Nanjing Forestry University, Nanjing, People's Republic of China
| | - Runan Tian
- College of Landscape Architecture, Nanjing Forestry University, Nanjing, People's Republic of China
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Song J, Li Y, Tang H, Qiu C, Lei L, Wang M, Xu H. Application potential of Vaccinium ashei R. for cadmium migration retention in the mining area soil. CHEMOSPHERE 2023; 324:138346. [PMID: 36893865 DOI: 10.1016/j.chemosphere.2023.138346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/28/2023] [Accepted: 03/07/2023] [Indexed: 06/18/2023]
Abstract
Despite numerous reports on phytoremediation of heavy metals contaminated soil, there are few reports on plant retention of heavy metals in the mining area slope. This study was the first of its kind to explore the cadmium (Cd) retention capacity of the blueberry (Vaccinium ashei Reade). Firstly, we investigated the stress response of blueberry to different soil Cd concentrations (1, 5, 10, 15, 20 mg/kg) to assess its potential for phytoremediation by pot experiments. The results showed that the blueberry biomass exposed to 10 and 15 mg/kg Cd was significantly increased compared with the control (1 mg/kg Cd); the blueberry crown increased by 0.40% and 0.34% in 10 and 15 mg/kg Cd-contaminated soil, respectively, compared with control; the blueberry heigh did not even change significantly in each treatment group; the total chlorophyll content, peroxidase and catalase activity of blueberry were enhanced in 5-20 mg/kg Cd treatments. Furthermore, the Cd contents of blueberry in the root, stem and leaf increased significantly as the Cd concentration of soil increased. We found that more Cd accumulated in blueberry root: the bioaccumulation concentration factor was root > stem > leaf for all groups; the residual-Cd (Cd speciation) in soil increased by 3.83%-411.11% in blueberry-planted versus unplanted groups; blueberry improved the Cd-contaminated soil micro-ecological environment including soil organic matter, available K and P, as well as microbial communities. Then, to investigate the effect of blueberry cultivation on Cd migration, we developed a bioretention model and revealed that soil Cd transport along the model slope was significantly weakened by blueberry cultivation, especially at the bottom of the model. In a word, this research suggests a promising method for the phytoremediation of Cd-contaminated soil and the reduction of Cd migration in mining areas.
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Affiliation(s)
- Jianjincang Song
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, PR China
| | - Yongyun Li
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, PR China
| | - Hao Tang
- Ecological Protection and Development Research Institute of Aba Tibetan and Qiang Autonomous Prefecture, Aba, 623000, Sichuan, PR China
| | - Chengshu Qiu
- College of Chemistry and Life Science, Chengdu Normal University, Chengdu, 61130, Sichuan, PR China
| | - Ling Lei
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, PR China
| | - Maolin Wang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, PR China
| | - Heng Xu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, PR China.
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Coimbra ECL, Borges AC. Removing Mn, Cu and Fe from Real Wastewaters with Macrophytes: Reviewing the Relationship between Environmental Factors and Plants' Uptake Capacity. TOXICS 2023; 11:158. [PMID: 36851032 PMCID: PMC9967775 DOI: 10.3390/toxics11020158] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/31/2023] [Accepted: 02/01/2023] [Indexed: 06/18/2023]
Abstract
Heavy metal pollution creates environmental health concerns. Among these, iron (Fe), copper (Cu) and manganese (Mn) are commonly found in aquatic environments due to the release of wastewaters. Phytoremediation in hydroponics uses macrophytes to treat contaminated environments, and this is influenced by environmental factors. However, the relationship between these factors and the removal of Fe, Cu and Mn by macrophytes is not known. Therefore, a meta-analysis serves to determine the correlations between environmental factors and the removal of these metals in real wastewater by macrophytes, as well as to identify the role of different aquatic forms of macrophytes in phytoremediation. Emergent macrophytes had higher concentrations of manganese in their tissues, and higher bioconcentrations factor of iron and manganese than floating plants. Regardless of the biotope, higher concentrations of Fe and Cu decreased the ability of plants to bioconcentrate them. The correlations among exposure time, pH, dissolved oxygen, nitrogen, phosphorus, photoperiod and metal phytoremediation by plants were also found. It can be concluded that the emergent macrophytes showed better performance in terms of the removal of Fe, Cu and Mn, and that the significant correlations between environmental factors and removal vary with the type of metal and the environmental factor analyzed.
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Electro-enhanced phytoremediation system on the removal of trace metal concentration from contaminated water. Heliyon 2022; 8:e11451. [PMID: 36406724 PMCID: PMC9667259 DOI: 10.1016/j.heliyon.2022.e11451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 08/19/2022] [Accepted: 11/01/2022] [Indexed: 11/11/2022] Open
Abstract
The combination of electro-enhanced and hydroponic phytoremediation hereinafter referred to as electro-enhanced phytoremediation (EP) system, has been employed for rapid removal of trace metal concentration of lead (II) from contaminated water using Kentucky bluegrass (Poa pratensis L.) as accumulator plant. In this study, for rapid assessment the effectiveness of two-dimensional (2D) electrode configuration in electro-enhanced system was evaluated by agar media for 48h period of time. Furthermore, these configurations were applied to enhance the EP system for 9d period of time. Also, a common agrochemical-urea as chaotropic agent to facilitate the healthy growth of plant in contaminated water was evaluated. The results showed that the accumulation of lead (II) concentration was higher in the plant roots (i.e. high bioaccumulation coefficient (BC) value) than in aerial parts of plant (i.e. low translocation factor (TF) value). Also, the accumulation of lead (II) concentration in plant was higher under the treated urea of EP system. The chlorophyll content, biomass accumulation productivity, and water content (i.e. dry weight-fresh weight (DW/FW) ratio) of plant either under the treated urea or untreated urea with high accumulation of lead (II) concentration revealed that the Kentucky bluegrass has able to hold out the plant stress.
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Xu Z, Li K, Li W, Wu C, Chen X, Huang J, Zhang X, Ban Y. The positive effects of arbuscular mycorrhizal fungi inoculation and/or additional aeration on the purification efficiency of combined heavy metals in vertical flow constructed wetlands. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:68950-68964. [PMID: 35554837 DOI: 10.1007/s11356-022-20759-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 05/07/2022] [Indexed: 06/15/2023]
Abstract
Inoculation with arbuscular mycorrhizal fungi (AMF) and additional aeration (AA), as two approaches to improve the functioning of treatment wetlands, can further promote the capacity of wetlands to purify pollutants. The extent to which, and mechanisms by which, AMF and AA purify wetlands polluted by combined heavy metals (HMs) are not well understood. In this study, the effects and mechanisms of AMF and/or AA on combined HMs removal in vertical flow constructed wetlands (VFCWs) with the Phragmites australis (reeds) were investigated at different HMs concentrations. The results showed that (1) AA improved the AMF colonization in VFCWs and AMF accumulated the combined HMs in their structures; (2) AMF inoculation and/or AA significantly promoted the reeds growth and antioxidant enzymes activities, thereby alleviating oxidative stress; (3) AMF inoculation and AA significantly enhanced the removal rates of Pb, Zn, Cu, and Cd under the stress of high combined HMs concentrations comparing to the control check (CK) treatment (autoclaved AMF inoculation and no aeration), which increased by 22.72%, 30.31%, 12.64%, and 50.22%, respectively; (4) AMF inoculation and/or AA significantly promoted the combined HMs accumulation in plant roots and substrates and altered the distribution of HMs at the subcellular level. We therefore conclude that AMF inoculation and/or AA in VFCWs improves the purification of combined HM-polluted water, and the VFCWs-reeds-AMF/AA associations exhibit great potential for application in remediation of combined HM-polluted wastewater.
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Affiliation(s)
- Zhouying Xu
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, Hubei, China
| | - Kaiguo Li
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, Hubei, China
| | - Wenxuan Li
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan, 430070, Hubei, China
| | - Chen Wu
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, Hubei, China
| | - Xi Chen
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, Hubei, China
| | - Jun Huang
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, Hubei, China
| | - Xiangling Zhang
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, Hubei, China
| | - Yihui Ban
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan, 430070, Hubei, China.
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Yang GL, Yang MX, Lv SM, Tan AJ. The effect of chelating agents on iron plaques and arsenic accumulation in duckweed (Lemna minor). JOURNAL OF HAZARDOUS MATERIALS 2021; 419:126410. [PMID: 34157466 DOI: 10.1016/j.jhazmat.2021.126410] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 06/11/2021] [Accepted: 06/12/2021] [Indexed: 06/13/2023]
Abstract
Iron plaques have been found to limit the phytoremediation efficiency by reducing iron solubility, while chelating agents can increase the bioavailability of iron from Fe plaques to numerous terrestrial plants. However, the effects of chelating agents on Fe plaques along the As accumulation in aquatic plants remain unknown. In this study, the effects of five chelating agents (EDTA, DTPA, NTA, GLDA, and CA) on the As (As(III) or As(V)), phosphate, and iron uptake by iron plaques and duckweed (Lemna minor) were examined. The results showed that the chelating agents increased the As accumulation in L. minor plants by desorbing and mobilizing As from Fe plaques. The desorption rates of As(V) (As(III)) from the Fe plaques by the chelating agents were 5.26-8.77% (8.70-15.02%), and the plants/DCB extract ratios of As(V) (As(III)) increased from 2.63 ± 0.13 (1.97 ± 0.06) to the peak value of 3.38 ± 0.21 (2.70 ± 0.14) upon adding chelating agents. Besides, the addition of chelating agents increased the uptake of P and Fe by L. minor plants. This work provides a theoretical basis for the remediation of As-contaminated waters by duckweed with the help of chelating agents.
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Affiliation(s)
- Gui-Li Yang
- College of Life Sciences, Guizhou University, Guiyang 550025, China.
| | - Ming-Xing Yang
- Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Shi-Ming Lv
- College of Animal Science, Guizhou University, Guiyang 50025, China
| | - Ai-Juan Tan
- College of Life Sciences, Guizhou University, Guiyang 550025, China.
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Mozaffari MH, Shafiepour E, Mirbagheri SA, Rakhshandehroo G, Wallace S, Stefanakis AI. Hydraulic characterization and removal of metals and nutrients in an aerated horizontal subsurface flow "racetrack" wetland treating primary-treated oil industry effluent. WATER RESEARCH 2021; 200:117220. [PMID: 34038821 DOI: 10.1016/j.watres.2021.117220] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 04/30/2021] [Accepted: 05/04/2021] [Indexed: 06/12/2023]
Abstract
Constructed wetlands (CW) are an attractive technology due to their operational simplicity and low life-cycle cost. It has been applied for refinery effluent treatment but mostly single-stage designs (e.g., vertical or horizontal flow) have been tested. However, to achieve a good treatment efficiency for industrial effluents, different treatment conditions (both aerobic and anaerobic) are needed. This means that hybrid CW systems are typically required with a respectively increased area demand. In addition, a strong aerobic environment that facilitates the formation of iron, manganese, zinc and aluminum precipitates cannot be established with passive wetland systems, while the role of these oxyhydroxide compounds in the further co-precipitation and removal of heavy metals such as copper, nickel, lead, and chromium that can simplify the overall treatment of industrial wastewaters is poorly understood in CW. Therefore, this study tests for the first time an innovative CW design that combines an artificially aerated section with a non-aerated section in a single unit applied for oil refinery wastewater treatment. Four pilot units were tested with different design (i.e., planted/unplanted, aerated/non-aerated) and operational (two different hydraulic loading rates) characteristics to estimate the role of plants and artificial aeration and to identify the optimum design configuration. The pilot units received a primary refinery effluent, i.e., after passing through a dissolved air flotation unit. The first-order removal of heavy metals under aerobic conditions is evaluated, along with the removal of phenols and nutrients. High removal rates for Fe (96-98%), Mn (38-81%), Al (49-73%), and Zn (99-100%) generally as oxyhydroxide precipitates were found, while removal of Cu (61-80%), Ni (70-85%), Pb (96-99%) and Cr (60-92%) under aerobic conditions was also observed, likely through co-precipitation. Complete phenols and ammonia nitrogen removal was also found. The first-order rate coefficient (k) calculated from the collected data demonstrates that the tested CW represents an advanced wetland design reaching higher removal rates at a smaller area demand than the common CW systems.
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Affiliation(s)
| | | | | | | | - Scott Wallace
- Naturally Wallace Consulting LLC, Stillwater, MN 55082, USA
| | - Alexandros I Stefanakis
- Laboratory of Environmental Engineering and Management, School of Environmental Engineering, Technical University of Crete, 73100 Chania, Greece.
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Viana DG, Egreja Filho FB, Pires FR, Soares MB, Ferreira AD, Bonomo R, Martins LF. In situ barium phytoremediation in flooded soil using Typha domingensis under different planting densities. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 210:111890. [PMID: 33440270 DOI: 10.1016/j.ecoenv.2021.111890] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/29/2020] [Accepted: 12/31/2020] [Indexed: 05/19/2023]
Abstract
The management of initial planting density can be a strategy to increase barium phytoextraction from soil, reducing the time required for soil decontamination. To delimit the ideal planting density for barium (Ba) phytoremediation using Typha domingensis, we conducted a 300-day experiment in an area accidentally contaminated with barite. Four initial planting densities were tested: 4, 8, 12, and 16 plantsm-2 (D4, D8, D12, and D16 treatments, respectively). Plant development was evaluated periodically, and the phytoextraction efficiency was determined at the end of the trial. The initial planting density affected Ba phytoremediation by T. domingensis monoculture. Phytoextraction potential was better represented by the mass-based translocation factor (mTF) than the concentration-based translocation factor. D16 promoted the highest final number of plants and biomass production, but the mass of Ba in the aerial part did not differ among D8, D12, and D16. D4 resulted in more Ba accumulated belowground than aboveground (6.3 times higher), whereas D12 and D16 achieved the greatest mTFs. Higher absorption of Ba from soil can be achieved using less T. domingensis individuals at the beginning of the treatment (D4 and D8) but with high accumulation in belowground tissues. We conclude that the D8 density is considered the most appropriate if considering the phytoextraction potential and field management facilitated using fewer plants.
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Affiliation(s)
- Douglas Gomes Viana
- Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba, SP, Brazil.
| | | | - Fábio Ribeiro Pires
- Department of Agricultural and Biological Sciences, Federal University of Espírito Santo, São Mateus, ES, Brazil
| | - Matheus Bortolanza Soares
- Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba, SP, Brazil
| | - Amanda Duim Ferreira
- Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba, SP, Brazil
| | - Robson Bonomo
- Department of Agricultural and Biological Sciences, Federal University of Espírito Santo, São Mateus, ES, Brazil
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Xin J, Ma S, Li Y, Zhao C, Tian R. Pontederia cordata, an ornamental aquatic macrophyte with great potential in phytoremediation of heavy-metal-contaminated wetlands. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 203:111024. [PMID: 32741747 DOI: 10.1016/j.ecoenv.2020.111024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 07/07/2020] [Accepted: 07/08/2020] [Indexed: 06/11/2023]
Abstract
Pontederia cordata can tolerate heavy metal toxicity and possesses great potential for phytoremediation of heavy-metal-contaminated wetlands, yet how it copes with heavy metal stress has still not been determined. Hydroponic experiments were used to assess the effects of various levels of Cd2+ on the photosynthesis and activity of redox-regulatory systems in the plant leaves, and we also sought to elucidate the tolerance mechanism of the plant to Cd2+ by investigating Cd2+ enrichment characteristics and chemical forms. The plant can manage a low cadmium concentration (≤0.04 mM) with relatively stable biomass and photosynthetic performance. Cd2+ at the highest concentration (0.44 mM) decreased superoxide dismutase and peroxidase activities by 37.17% and 93.29%, respectively. Similar trends were demonstrated in the contents of ascorbic acid, carotenoids, lutein, glutathione, and non-protein thiol, as well as phytochelation in the leaves, exacerbating membrane peroxidation despite the significantly increased catalase activity observed. Moreover, the highest Cd2+ concentration disturbed the biosynthesis of chlorophyll precursors in the leaves, reduced chlorophyll a and b, as well as total chlorophyll contents by 60.47%, 67.47%, and 68.12%, respectively, which inhibited photosynthesis, leading to a decline in biomass. Compared with maximum quantum efficiency (Fv/Fm) and the potential activity (Fv/Fo) of photosystem II, the performance index for energy conservation from photons absorbed by PSII to the reduction of intersystem electron acceptors (PIabs), and of PSI end acceptors (PItotal), can indicate Cd2+ toxicity to the photosynthetic apparatus in the leaves. 49.95%-76.90% of the Cd2+ was sequestered in the plant roots, restraining translocation from roots to shoots, which is considered a tolerance mechanism, probably resulting from disturbed transpiration in leaves and increased Cd2+ content with low activity. Pontederia cordata is a candidate plant for phytoremediation of heavy-metal -contaminated wetlands.
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Affiliation(s)
- Jianpan Xin
- College of Architeture Landscape, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
| | - Sisi Ma
- College of Architeture Landscape, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
| | - Yan Li
- College of Architeture Landscape, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
| | - Chu Zhao
- College of Architeture Landscape, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
| | - Runan Tian
- College of Architeture Landscape, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China.
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