Search Results (240)

The enhanced performance of electrokinetics (EK) on the cadmium (Cd) dissociation, redistribution, and phytoremediation of Cd-contaminated agricultural soil has been investigated based on the application of an electric field in different dimensions (1D, 2D, 3D). In electrokinetic–assisted phytoremediation (EKPR), unlike the uniform pH change observed in 1D treatment, more soil points (P1–P9) under 2D/3D electric fields were exposed to the influence of the anode (or cathode during polarity switching). Sedum plumbizincicola mitigates EK-induced soil acidification and alkalization, particularly anode acidification under high voltage (10–20 V). Studies reveal that EK promotes Cd dissolution into soil pore water, with a 227.82% maximum increase in the anode region under EK2 treatment of 10 V voltage, facilitating Cd phytoextraction. Periodically reversed DC electric fields enhanced Sedum plumbizincicola height more significantly than biomass, with no conspicuous regional differences. Overall, EKPR (voltage of 5–10 V) can effectively promote soil Cd phytoremediation due to the synergistic effect of direct interface action and indirect influence of the electric field to improve the Cd speciation evolution, dissociation, and bioavailability at the soil–water interface. The appropriate electric field arrangement and voltage were 2D treatment (EKPR2) and 5 V for S. plumbizincicola, respectively. In this case, the average Cd removal rate was as high as 50.23%, and the biomass and Cd accumulation increased by 16.59% and 29.31%. This suggests that plant growth constitutes the pivotal stage driving Cd accumulation and ultimately achieving Cd removal from soil, which is the key to enhancing remediation efficiency. Meanwhile, the configuration and intensity regulation of electric fields, as core elements ensuring the enhanced efficacy of electrokinetic–assisted phytoremediation (EKPR), can indirectly affect plant growth and Cd accumulation processes by modulating intermediate variables such as soil pH, nutrient status, and heavy metal speciation evolution. Full article

The SPIRE project, conducted in Baia Mare, Romania, investigated the use of nature-based solutions for the phytoremediation of soils contaminated with heavy metals such as lead (Pb), cadmium (Cd), copper (Cu), and zinc (Zn). In five pilot sites with various levels of pollution a selection of species were planted based on their potential for remediation. The results suggested that species such as Salix alba, Salix viminalis, Reynoutria japonica, Betula pendula, and Agrostis capillaris were effective in the absorption of high concentrations of heavy metals, especially cadmium and zinc. Data analysis showed distinct patterns of heavy metal uptake depending on location and species and highlighted the importance of adapting remediation strategies to local conditions. The study demonstrates the applicability of phytoremediation in post-industrial urban environments, with significant reductions in soil contaminants and potential for ecological remediation. Full article

This study systematically investigates cadmium (Cd) accumulation and translocation mechanisms in woody plants through integrated analysis of 16 species. Roots consistently exhibited the highest Cd concentrations (0.26 ± 0.13 mg/kg), serving as primary accumulation sites, while bark functioned as a critical secondary storage organ (0.22 ± 0.09 mg/kg) with strong physiological coordination to roots (r = 0.72, p < 0.001). Leaves demonstrated strict Cd restriction (0.09 ± 0.05 mg/kg) and low variability (CV = 48.7%), indicating evolutionary adaptations to minimize phytotoxicity in photosynthetic tissues. Three functional groups were identified: hyperaccumulators (e.g., Ulmus pumila, root/leaf ratio = 6.37), excluders (e.g., Malus spectabilis, root/leaf ratio = 1.12), and intermediate species (e.g., Syringa oblata) with balanced translocation patterns. Strong root-bark correlations (r = 0.68) and negative stem-leaf associations (r = −0.42) revealed complex interorgan translocation dynamics. Cd speciation analysis showed dominant residual fractions in soils (60–80%) and elevated water-soluble or weakly bound Cd in roots (35–52%). These findings provide a mechanistic basis for designing species-specific phytoremediation strategies, including phytoextraction and ecological stabilization. It will identify suitable tree species for effectively stabilizing or containing the metal pollution within a defined area, thereby preventing its lateral spread or leaching. Full article

Cadmium (Cd) pollution is a global environmental issue that severely impacts crop growth and food safety. This study systematically investigates the accumulation characteristics and physiological responses of different varieties of non-heading Chinese cabbage under Cd stress. A Cd stress experiment was conducted using 79 non-heading Chinese cabbage varieties under nutrient film technique (NFT) cultivation, leading to the identification of 11 high-Cd accumulation varieties, 32 medium-Cd accumulation varieties, and 36 low-Cd accumulation varieties. The results showed that all varieties primarily accumulated Cd in the roots, with weak translocation of Cd to the aerial parts. To thoroughly analyze the physiological mechanisms of Cd accumulation, two extreme phenotypes, low accumulation (GX-61) and high accumulation (GX-05), were selected for subsequent comprehensive analysis. The low-accumulation variety (GX-61) exhibited higher sensitivity to Cd stress, with significant inhibition of leaf area, canopy area, and photosynthesis. In contrast, the high-accumulation variety (GX-05) maintained a more stable physiological state by enhancing photoprotective capacity and activating peroxidase (POD) to compensate for the functional loss of catalase (CAT). Cd stress inhibition of photosynthesis was initially limited by stomatal factors, later transitioning to non-stomatal limitations, and low concentrations of Cd induced a protective response that slightly promoted plant growth. This study, through high temporal resolution analysis at key growth stages, reveals the differential responses in growth, photosynthesis, and physiological metabolism between low- and high-Cd-accumulating non-heading Chinese cabbages, providing a theoretical basis for the selection of efficient phytoremediation materials and the safe production of non-heading Chinese cabbage. Full article

Seed biopriming is increasingly recognized as a strategy capable of inducing molecular memory that enhances plant performance under heavy-metal stress. Here, we investigated how biopriming Silene sendtneri seeds with Paraburkholderia phytofirmans PsJN establishes a transcriptional state that predisposes seedlings for improved cadmium (Cd) tolerance. RNA-seq profiling revealed that primed seeds exhibited differential gene expression prior to Cd exposure, with strong upregulation of detoxification enzymes, antioxidant machinery, metal transporters, photosynthetic stabilizers, and osmoprotectant biosynthetic genes. Enrichment of gene ontology categories related to metal ion detoxification, redox homeostasis, phenylpropanoid metabolism, and cell wall organization indicated that biopriming imprints a preparatory transcriptional signature resembling early stress responses. Upon Cd exposure, primed plants displayed enhanced physiological performance, including preserved integrity, elevated antioxidant activity, particularly peroxidases in roots, higher osmolyte accumulation, stabilized micronutrient levels, and substantially increased Cd uptake and sequestration. These coordinated responses demonstrate that biopriming induces a sustained molecular memory that accelerates and strengthens downstream defense activation. These findings demonstrate that PGPR-based biopriming establishes a stable transcriptomic memory in seeds that enhances cadmium tolerance, metal sequestration, and stress resilience, highlighting its potential for improving hyperaccumulator performance in phytoremediation and stress adaptation strategies. Full article

Soil co-contamination with cadmium (Cd) and zinc (Zn) poses serious threats to environmental safety and public health. This study investigates the enhancement effect and underlying mechanism of the biodegradable chelator Ethylenediamine-N,N′-disuccinic acid (EDDS) on phytoremediation of Cd-Zn contaminated soil using Sedum lineare. The results demonstrate that EDDS application (3.65 g·L⁻¹) effectively alleviated metal-induced phytotoxicity by enhancing chlorophyll synthesis, activating antioxidant enzymes (catalase and dismutase), regulating S-nitrosoglutathione reductase activity, and promoting leaf protein synthesis, thereby improving photosynthetic performance and cellular integrity. The combined treatment significantly increased the bioavailability of Cd and Zn in soil, promoted their transformation into exchangeable fraction, and resulted in removal rates of 30.8% and 28.9%, respectively. EDDS also modified the interaction patterns between heavy metals and essential nutrients, particularly the competitive relationships through selective chelation between Cd/Zn and Fe/Mn during plant uptake. Soil health was substantially improved, as evidenced by reduced electrical conductivity, enhanced cation exchange capacity, and enriched beneficial microbial communities including Sphingomonadaceae. Based on the observed ion antagonism during metal uptake and translocation, this study proposes a novel “Nutrient Regulation Assisted Remediation” strategy to optimize heavy metal accumulation and improve remediation efficiency through rhizosphere nutrient management. These findings confirm the EDDS–S. lineare system as an efficient and sustainable solution for remediation of Cd–Zn co-contaminated soils. Full article

Cadmium (Cd) contamination in agricultural soils threatens food security and exacerbates climate change through its impact on greenhouse gas (GHG) (CO₂, N₂O and CH₄) emissions, in which N₂O and CO₂ are the dominant fluxes of the terrestrial carbon-nitrogen cycle whose magnitude is directly amplified by Cd stress. Key remediation approaches for this dual challenge are phytoremediation and biochar amendment. This study aims to investigate the effects of Solidago canadensis (CGR) and biochar (BC) on soil remediation and GHG emissions under different levels of Cd contamination. A pot experiment with four Cd concentration gradients (0, 5, 10, and 30 mg kg⁻¹, i.e., Cd-0, Cd-5, Cd-10, and Cd-30, respectively) and three remediation measures (control, BC addition, and CGR cultivation) was set up to measure available soil Cd (ACd), soil physicochemical properties, GHG emissions, and plant Cd accumulations. The results demonstrated that ACd was significantly reduced by BC via adsorption through surface complexation and by CGR via immobilization through root uptake and sequestration. CGR decreased ACd by 46.2% and 41.7% under mild and moderate Cd contamination, respectively, while BC reduced ACd by 8.9% under severe contamination. In terms of GHG emissions, CGR increased cumulative CO₂ by 83.4% in Cd-10 soil and 53.8% in Cd-30 soil, whereas BC significantly lowered N₂O emissions by 22.1% in Cd-5 soil. Mantel analysis revealed strong correlations between ACd and key carbon and nitrogen indicators, which mediate the bioavailability of Cd. Therefore, CGR cultivation is better suited to mild-to-moderate contamination given its high removal efficiency, while BC amendment is targeted at severe contamination by stabilizing Cd and mitigating N₂O. This provides a scientific basis for the remediation of Cd-contaminated soils. Full article

Cadmium (Cd) is a pervasive and highly toxic heavy metal that severely threatens environmental integrity, agricultural systems, plant metabolism, ecosystem health, and human food safety. Plants have evolved intricate detoxification mechanisms aimed at mitigating heavy metal toxicity, in which ATP-binding cassette (ABC) transporters play pivotal roles. This article contextualizes findings on the functional genetic manipulation of plant ABC transporters in Cd-exposed species, integrating evidence from model plants, crops, and transgenic systems. Key insights reveal how these transporters contribute to Cd distribution through multiple cellular and physiological pathways. We highlight the contribution of ABC transporters both in modulating Cd accumulation in plant tissues for food safety considerations and in regulating Cd-related parameters relevant to environmental cleanup and phytoremediation. Functional studies in different plant species demonstrate differential outcomes depending on transporter specificity and regulatory context. Cross-kingdom engineering further expands the biotechnological toolkit for Cd mitigation. Additionally, we performed a bibliometric analysis that underscores research trends linking ABC transporters with genetic manipulation strategies. The body of evidence highlights the perspective that precise modulation of ABC transporters—through strategies such as multi-gene engineering, tissue-specific expression, or fine-tuned regulatory approaches—offers a promising yet complex route to reconcile scientific and applied Cd management strategies. Full article

Soil contamination with heavy metals is a persistent challenge in the arid regions of Kazakhstan. This study evaluates the phytoremediation potential of sweet sorghum (Sorghum bicolor L.), a drought-tolerant crop with a well-developed root system, using a combination of in vitro and analytical approaches. In vitro culture of somatic cells revealed clear genotype-dependent differences in callus induction and morphogenesis, with Hybrid-2 and SAB-3 exhibiting the highest regenerative capacity and thus the greatest suitability for further biotechnological improvement and stress-tolerance selection. Analysis of metal distribution, based on atomic absorption spectroscopy (AAS), demonstrated that S. bicolor predominantly retained Pb, Cd, and Co in the root system. Cobalt accumulated to 12.7 ± 1.32 mg/kg under 1 MAC and 16.87 ± 2.78 mg/kg under 2 MAC, accounting for more than half of the metal absorbed by plants. Cadmium showed a similar root-dominant pattern, whereas lead exhibited the lowest mobility and remained almost entirely sequestered in roots, with translocation factors consistently below unity (TF < 1). Overall, these findings confirm the suitability of sweet sorghum as an environmentally sustainable species for the phytostabilization of Pb-, Cd-, and Co-contaminated soils in arid environments and highlight the value of genotype pre-selection under stress conditions for optimizing phytoremediation performance. Full article

Phytoremediation utilizing woody plants represents a promising approach for mitigating cadmium (Cd) contamination; however, the potential of ornamental species such as Punica granatum L. (pomegranate) remains insufficiently characterized. This study evaluated the growth performance, physiological responses, and Cd accumulation patterns of pomegranate seedlings exposed to increasing Cd concentrations (T1–T6) in a hydroponic system. High Cd levels (≥T4) markedly suppressed plant growth, as evidenced by reductions in biomass, root necrosis, leaf wilting, and chlorosis. Photosynthetic efficiency was severely compromised, indicated by significant declines in chlorophyll content and key chlorophyll fluorescence parameters (Fv/Fm, ΦPSII, and qP). Simultaneously, increases in the chlorophyll a/b ratio, carotenoid content, and non-photochemical quenching (NPQ) reflected the activation of photoprotective mechanisms. A reduction in stomatal conductance (G_s) and net photosynthetic rate (P_n), coupled with elevated intercellular CO₂ concentration (C_i), suggested that non-stomatal limitations were primarily responsible for photosynthetic inhibition. Cd exposure also triggered oxidative stress, as shown by increased levels of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂). In response, seedlings activated antioxidative and osmotic adjustment pathways, including elevated peroxidase (POD) activity and the accumulation of glutathione (GSH), proline, soluble proteins, and sugars. Notably, pomegranate displayed a root-based Cd sequestration strategy, with high root accumulation (bioconcentration factor, BCF > 271) and minimal translocation to aerial tissues (translocation factor, TF < 0.17). These findings demonstrate that pomegranate seedlings exhibit pronounced tolerance to Cd stress and substantial bioaccumulation capacity, supporting their potential application as ornamental woody species for phytoremediation of Cd-contaminated environments. Full article

The detrimental effects of anthropogenic pollution are often magnified across ecosystems due to the interconnected nature of land, rivers, and oceans. Phytoremediation is an accessible technique that leverages the ability of plants to absorb and sequester pollutants and can potentially mitigate contaminants entering the ocean. It is a cost-effective and minimally invasive alternative to traditional water treatment methods. This study investigates the potential of the grapevine species Cissus verticillata (L.), a native plant from Puerto Rico, to be used in the phytoremediation of a creek in a highly urbanized site impacted by contaminated runoff due to heavy rainfall and sanitary waters. A mesocosm experiment was conducted using distilled water mixed with nutrients and known concentrations of cadmium (Cd) and lead (Pb) salts to assess whether C. verticillata could accumulate heavy metals in its tissues. Results showed that C. verticillata successfully absorbed heavy metals, with removal efficiencies of 80.13% (±0.16 SE) for Pb and 44% (±1 SE) for Cd. Results indicated a translocation factor <1 for both cadmium and lead, meaning C. verticillata is not a hyperaccumulator, but a metal stabilizer, as evident by the below detection limit (BDL) of the metals in Juan Mendez Creek. Despite evidence of new vegetative growth among individuals, no significant changes in total biomass or chlorophyll concentration were detected, indicating that C. verticillata maintained physiological stability under heavy metal exposure. Therefore, C. verticillata’s wide availability, adaptability to various environments, and climbing nature—which makes it less vulnerable to runoff and strong currents during rainy seasons—position it as a promising candidate for conservation initiatives and pollution management strategies. Full article

A two-year field study was performed to evaluate the cadmium (Cd) phytoremediation potential of two hyperaccumulators, Sedum alfredii (S.A.) and Sedum plumbizincicola (S.P.), in contaminated farmland. Biomass and Cd uptake in both species followed logistic growth models. S.A. reached maturity about 20 days earlier than S.P., with optimal harvest timing at the early late-flowering stage (early–mid May), compared to the full late-flowering stage (early June) for S.P. The primary Cd-accumulating organs were stems and flowers in S.A. and leaves and stems in S.P. Under identical conditions, S.P. exhibited higher theoretical biomass, Cd content, bioconcentration factor (BCF), and Cd uptake, supported by transcriptomic data showing upregulation of metal transporter and stress-related genes under Cd exposure. However, S.P. demonstrated greater environmental sensitivity and lower stress resistance, resulting in more variable real-world remediation efficiency than S.A. It is recommended to harvest at flowering stages, enhance biomass in key Cd-accumulating tissues, and select species based on local conditions. Future work should aim to breed Sedum varieties with greater biomass, Cd accumulation capacity, and stress tolerance. This study provides actionable insights for optimizing the timing and species selection in Cd phytoremediation. Full article

As a typical heavy metal pollutant, cadmium (Cd) poses significant threats to ecosystems and human health. Giant duckweed (Spirodela polyrhiza), a small aquatic plant characterized by rapid growth and efficient heavy metal accumulation, holds great promise for phytoremediation. However, the mechanisms by which S. polyrhiza enriches Cd—particularly the contributions of its surface-associated microbiota—remain poorly understood. In this study, S. polyrhiza fronds were exposed to 0, 1, and 10 μM Cd, and we observed a concentration-dependent increase in the abundance of epiphytic microorganisms on the frond surfaces. High-throughput 16S rRNA gene sequencing revealed that Cd stress significantly altered the diversity of the frond-epiphytic bacterial community. Notably, the relative abundances of the genera Herbaspirillum, Enterobacter, and Pantoea increased significantly with rising Cd concentrations. Functional prediction using PICRUSt2 indicated enrichment under Cd stress of specific traits—such as the nitrate/nitrite transporter NarK, signal transduction mechanisms, and ion channel proteins—suggesting these taxa may actively participate in Cd uptake and tolerance. Together, our results reveal a synergistic S. polyrhiza–microbiome response to Cd and identify taxa/functions as targets and biomarkers for microbe-augmented remediation. Full article

Cadmium (Cd) contamination in agricultural soils originates mainly from atmospheric deposition, irrigation water, fertilizers, pesticides, and industrial waste discharges. This human-induced pollution adversely affects soil fertility and structure, disrupts plant growth and physiological activities, and poses severe health risks through food-chain accumulation. Despite increasing research attention, comprehensive assessments that integrate global patterns, remediation strategies, and knowledge gaps remain limited. Therefore, this literature review critically synthesizes findings from 1060 peer-reviewed studies (screened using PRISMA guidelines) retrieved from Scopus and Web of Science databases, focusing on Cd sources, environmental behavior, plant responses, and soil remediation techniques. Results show that most research has been concentrated in Asia—particularly China—and Latin America. The most frequently investigated topics include Cd accumulation in crops, soil amendments, phytoremediation, and microbial-assisted remediation. Among remediation strategies, assisted phytoremediation and integrated biological–chemical approaches (biochar, PGPR, and soil amendments) emerged as the most promising for sustainable Cd mitigation. In conclusion, this review highlights regional disparities in research coverage, emphasizes the effectiveness of combined remediation approaches, and identifies the need for interdisciplinary and field-scale studies to advance sustainable solutions for Cd pollution control in agricultural systems. Full article

The use of biodegradable chelating agents and fertilizer to improve phytoremediation is a cost-effective and environmental-friendly method for remediation of copper (Cu)- and cadmium (Cd)-polluted agricultural soil. A pot experiment was conducted to investigate the effects of phosphorus (P) fertilizer and the chelator ethylenediamine disuccinic acid (EDDS), both individually and in combination, on the phytoremediation efficiency of castor plants. The experiment included six treatments with three replicates, which were as follows: control (no P or EDDS), EDDS alone, P at 100 mg kg⁻¹, P at 300 mg kg⁻¹, P at 100 mg kg⁻¹ + EDDS, and P at 300 mg kg⁻¹ + EDDS. The results demonstrated that phosphorus significantly promoted the growth of castor plants. In the treatment in which 300 mg kg⁻¹ P₂O₅ and 5.0 mmol kg⁻¹ EDDS were added, the shoot dry weight and root dry weight increased by 42.0% and 67.6%, respectively, when compared to the treatment only applying EDDS, and this treatment significantly promoted the absorption of Cd by shoots of castor. In the absence of phosphorus application, EDDS significantly diminished the dry weight of castor roots by 27.3%. Nevertheless, it improved the concentrations of Cu in the shoots and roots of castor plants, which were 3.43 times and 3.27 times higher than those of the control, respectively. Furthermore, when combined with phosphorus fertilizers, EDDS further promoted the absorption of Cu and Cd in the shoots of castor, which significantly increased by 13.34 times and 0.47 times, respectively, with addition of 100 mg kg⁻¹ phosphorus and 5.0 mmol kg⁻¹ of EDDS compared with the control. Phosphorus and EDDS synergistically decreased the activity of POD enzymes in leaves and roots compared with those treated with only EDDS and alleviated the toxicity of EDDS and heavy metals to castor plants. These findings provide scientific evidence for the use of agronomic measures and chelators to optimize phytoremediation efficiency in Cu and Cd co-contaminated soils. Full article