The efficacy and environmental effects of using metal-organic frameworks (MOFs) for the remediation of arsenic (As)-contaminated soil, a significant global problem, remain unclear. This study evaluated MIL-88A(Fe) and MIL101(Fe) coupled with ramie (Boehmeria nivea L.) for As-contaminated soil remediation. A soil incubation experiment revealed that 10,000 mg kg-1 MIL-88A(Fe) and MIL-101(Fe) reduced As bioavailability by 77.1 % and 65.0 %, respectively, and increased residual As fractions by 8 % and 7 % through Fe-As co-precipitation and adsorption. Divergent environmental effects emerged, which were probably due to differences in the framework structures and organic ligands: MIL-88A(Fe) improved soil urease activity and bacterial diversity, whereas MIL101(Fe) induced acidification (decreasing soil pH by 25 %) and salinity stress (elevating soil electrical conductivity (EC) by 946 %). A pot experiment showed that 1000 mg kg-1 MOFs enhanced ramie biomass via As immobilization, whereas 5000 mg kg-1 MIL-101(Fe) suppressed growth because exposure to the MOF caused root damage. The MOFs enriched Pseudomonas (As-oxidizing) and suppressed Dokdonella (pathogenic), enhancing plant resilience. Notably, 100 mg kg-1 MIL-101(Fe) increased As translocation to stems (14.8 %) and leaves (27.6 %). Hydroponic analyses showed that 50-200 mg L-1 MIL-101(Fe) mitigated As-induced chlorophyll degradation (elevating Soil and plant analyzer development (SPAD) by 12.8 %-28.3 %), whereas 500 and 1000 mg L-1 induced oxidative stress (reducing SPAD by 4.2 %-10.7 %). This study provides valuable insights into using Fe-based MOFs in soil remediation and highlights their beneficial and harmful effects.

Biochar has been considered a promising material for soil carbon sequestration. However, there are huge knowledge gaps regarding the carbon reduction effects of biochar-plant-polluted soil. Here, rice straw biochar (RB) was applied in ryegrass-cadmium (Cd)-contaminated soil to investigate the full-cycle carbon dioxide (CO2) emission and intrinsic mechanism. RB resulted in a 37.00 %-115.64 % reduction in accumulative CO2 emissions and a 31.61 %-45.80 % reduction in soil bioavailable Cd throughout the whole phytoremediation period. CO2 emission reduction triggered by RB can be attributed to the regulation of plant and rhizosphere ecological functions. RB could bolster photosynthetic carbon fixation by maintaining the stability of the structure of the chloroplasts and thylakoids, accelerating the consumption of terminal photosynthate, upregulating photosynthetic pigments, and mitigating oxidative damage. Besides, RB reduced the metabolism of readily mineralizable carbon sources while reinforcing the utilization of certain nutrient substrates. Besides, the composition of rhizosphere microbial communities was altered, especially those associated with carbon cycling (Chloroflexi, Actinobacteriota, and Acidobacteriota phyla) to orient soil microbial evolution to lower soil CO2 emission. This study aims to establish a win-win paradigm of carbon reduction-pollution alleviation to deepen the understanding of biochar in carbon neutrality and soil health and provide a theoretical basis for field pilot-scale studies.

Arsenic contamination poses a significant threat to agricultural productivity and food security, especially in Cicer arietinum L. (chickpea). This study evaluates the potential of silicon nanoparticles (SiNPs) to mitigate arsenic stress in C. arietinum (Noor 2022). The experiment was conducted at The Islamia University of Bahawalpur using a randomized complete block design (RCBD) with a factorial arrangement and three replications. A pot experiment was conducted using seven treatments comprising various concentrations of SiNPs applied alone or combined with arsenic [T0 (control, no SiNPs), T1 (3.5% SiNPs), T2 (7% SiNPs), T3 (10.5% SiNPs), T4 (3.5% SiNPs + 30 ppm Ar), T5 (7% SiNPs + 30 ppm Ar), and T6 (10.5% SiNPs + 30 ppm Ar)]. SiNPs were applied as foliar sprays in three splits from the second to fourth weeks after sowing. Morphological, physiological, and biochemical parameters were assessed, including chlorophyll content, total soluble proteins, proline, and antioxidant enzyme activities. The results demonstrated that SiNPs significantly enhanced stress tolerance in chickpea plants. At 10.5% SiNPs, chlorophyll content increased by 35%, carotenoids by 42%, and proline by 68% compared to arsenic-stressed plants without SiNPs, indicating improved photosynthetic efficiency and osmotic adjustment. Antioxidant enzyme activities, including peroxidase (POD), superoxide dismutase (SOD), and ascorbate peroxidase (APX), increased by 50%, 47%, and 53%, respectively, mitigating oxidative damage. Soluble sugars and phenolic content also rose by 28% and 32%, respectively, under 10.5% SiNPs. However, when combined with arsenic, some antagonistic effects were observed, with a slight decrease in chlorophyll and antioxidant activity compared to SiNPs alone. These findings suggest that SiNPs are a promising tool for improving crop resilience in arsenic-contaminated soils, offering insights into sustainable agricultural practices. Further research is warranted to explore long-term impacts and optimize application strategies.

Cadmium (Cd) is one of the most harmful heavy metals in the environment, negatively impacting plant growth and development. However, phytoremediation which is an environmentally friendly and cost-effective technique can be used to treat Cd contaminated environments. It effectively removes Cd from polluted soil and water through processes, such as phytoextraction, phytostabilization, phytostimulation, phytofiltration, and phytotransformation. Numerous research has shown evidences that biological, physical, chemical, agronomic, and genetic methods are being utilized to improve phytoremediation. A special group of plants known as hyperaccumulator plants further enhance Cd removal, turning polluted areas into productive land. These plants accumulate Cd in root cell vacuoles and aerial parts. Despite the morphological and genetic variations, different plant species remediate Cd at different rates using either one or multiple mechanisms. To improve the effectiveness of phytoremediation, it is essential to thoroughly understand the mechanisms that control the accumulation and persistence of Cd in plants, including absorption, translocation, and elimination processes. However, what missing in understanding is in depth of idea on how the limitations of phytoremediation can be overcome. The limitations of phytoremediation can be addressed through various strategies, including natural and chemical amendments, genetic engineering, and natural microbial stimulation, broadly categorized into soil amelioration and plant capacity enhancement approaches. This review presents a concise overview of the latest research on various plants utilized in Cd phytoremediation and the different methods employed to enhance this process. Moreover, this review also underscores the creditability of phytoremediation technique to remediate Cd pollution as it offers a promising approach for eliminating Cd from contaminated sites and restoring their productivity. Additionally, we recommend directing future research toward enhancing the biochemical capabilities of plants for remediation purposes, elucidating the molecular mechanisms underlying the damage caused by Cd in plants, and understanding the fundamental principles regulating the enrichment of Cd in plants.

Phytoremediation of soils contaminated with high concentrations of multiple heavy metals (HCMHMs) is a promising technique. However, the microbial response mechanisms during the phytoremediation process remain poorly understood. The role of microbes in HCMHMs soil remediation may be underestimated. This study investigated microbial responses and their potential roles in HCMHMs soil remediation using the hyperaccumulator plant Sedum alfredii (S. alfredii). Soil microbial communities were characterised by 16S rRNA sequencing, and metabolic pathways and functions were predicted using PICRUSt2 analysis. The results indicated that the impact of heavy metals on bacterial community structure was more significant than that of S. alfredii. The formation of dominant phyla such as Proteobacteria and Patescibacteria played a crucial role in the bacterial remediation of HCMHMs soils. Proteobacteria utilised the Inorganic ion transport and metabolism gene clusters to translocate heavy metals or reduce their bioavailability and toxicity. Patescibacteria used the Replication, recombination and repair gene clusters to repair damaged genes, enhancing bacterial tolerance of heavy metals. The results provided new insights into the role of microbes during phytoremediation and offered a scientific basis for optimizing phytoremediation technologies. This study demonstrated that dominant phyla effectively mitigated the damage to soil ecological functions from HCMHMs soil.

Soil polycyclic aromatic hydrocarbons (PAHs) and cadmium (Cd) pollution poses severe threats to environment security. Previous studies have reported that both nanoparticles and humic acid (HA) have ability to phytoremediate of pyrene/Cd in soil. Here, pot experiments were conducted to investigate the effects of TiO2NPs and humic acid addition on the applicability Hylotelephium spectabile of remediation for pyrene-Cd co-contaminated soil and the corresponding plant growth. The results show that TiO2NPs with HA can mitigate the damage to plant physiology. TiO2NPs-HA is more suitable to be applied on composite soil where Cd pollution is dominant and pyrene pollution is light. Furthermore, the coating of TiO2NPs with HA enhances the availability of Cd and expands root xylem, allowing roots to absorb and accumulate Cd in large quantities finally. This study aims to establish a theoretical foundation for the implementation of sedum plant in remediating soil contaminated with multiple pollutants.

Introduction Arbuscular mycorrhizal fungi (AMF) show significant potential for improving plant tolerance to vanadium (V) stress. However, the pattern and physiological mechanisms behind this effect are not fully understood.Methods To investigate this, we used green foxtail (Setaria viridis) as a test plant and inoculated this plant with (+AMF) or without (-AMF) Rhizophagus irregularis. These +AMF and -AMF plants were grown in soils with low (150 mg kg-1), medium (500 mg kg-1), and high (1000 mg kg-1) V pollution levels.Results Our results showed root colonization of +AMF plants, whereas no such colonization was observed in -AMF plants. Compared to -AMF plants, +AMF plants showed a more organized arrangement of leaf cells, intact chloroplasts, fewer starch granules, and an intact nuclear membrane. AMF increased leaf chlorophyll a concentration by 49% under high V pollution and that of chlorophyll b by 18% under low V pollution and 36% at medium soil V levels. AMF reduced the concentration of malondialdehyde (MDA) by 36%-40% in leaves and increased the activities of superoxide dismutase (SOD) by 20%-84%, catalase (CAT) by 5%-13%, and peroxidase (POD) by 12%-16%. +AMF plants exhibited 13%-32% greater plant height, 17%-23% longer root length, 42%-78% higher shoot biomass, 61%-73% greater root biomass, 16% increased root-to-shoot ratio (at high V pollution), and 7%-13% elevated leaf phosphorus concentration than -AMF plants. Furthermore, +AMF shoots had 16%-30% lower V concentrations than -AMF plants while +AMF roots exhibited 52%-73% smaller V concentrations than the -AMF control.Discussion These results suggest that AMF increase plant tolerance to V stress by protecting leaf ultrastructure, increasing chlorophyll concentration, reducing oxidative damage as well as biomass-driven V dilution and these effects of AMF were independent of soil V concentrations.

Phytoremediation is a promising approach grounded in green and sustainable development principles for decontaminating water and soil. Among the studied duckweed species (Spirodela polyrhiza, Wolffia arrhizal, and Lemna minor), S. polyrhiza exhibited the highest zinc removal efficiency of 88.50% by day 7, followed by L. minor and W. arrhiza with removal efficiency of 78.69 and 38.59%, respectively. This study investigated the effects of environmental factors, including initial zinc ion concentration (50, 100, 150, 200, and 250 mg/L), solution pH (pH 5, 6, 7, and 8), and macrophytes mass (5, 10, 15, 20, and 25 g) on the phytoremediation of the zinc ion from synthetic wastewater by S. polyrhiza. The process effectively treated 500 mL of synthetic wastewater containing 100 ppm zinc ion and the process could be enhanced to achieve the removal efficiency of 90% by adjusting the solution pH to slightly acidic (pH 5) and increasing the mass of duckweed to its saturation point (20 g). Excessive zinc intake by duckweed led to chlorophyll reduction, negatively impacting the duckweed growth rate. Scanning electron microscopy (SEM) analysis revealed that the duckweed fronds' surface became uneven after the treatment, with the irregular small particles attached due to cellular damage. The energy dispersive X-ray (EDX) analysis confirmed the successful uptake and accumulation of zinc in the duckweed cells from the synthetic wastewater. In conclusion, duckweed-based phytoremediation demonstrates significant potential for removing zinc ion from wastewater, at low and moderate concentrations.

Anthropogenic activities enhance the concentration of trace elements in environment like highly carcinogenic Cadmium (Cd), which adversely affect the plant growth and development. They deliberately accumulate defense compounds e.g., flavonoids, terpenoids, and alkaloids to ensure resilience in such adverse conditions. Current study explores the adaptive evolution, structural complexity, and functional roles of Flavin Adenine Dinucleotide (FAD)-linked oxidase genes in widespread leading cash crop cotton. As a non-edible, hyperaccumulator halophyte crop, cotton is an excellent candidate for phytoremediation of Cd-polluted soils by manipulating stress resistant genetic material. They utilize FAD as a cofactor to drive oxidative reactions, including benzylisoquinoline alkaloid biosynthesis, which plays a critical role in cellular signaling pathways, stress responses and metabolic processes. A total of 387 FADs retrieved from four cotton species were distributed into seven families and twelve subfamilies. They underwent large scale expansion under intense purifying selection with lineagespecific gene loss and retention, reflecting their ongoing evolution for functional advancements to adopt altering environment. High throughput transcriptomic, functional enrichment and qRT-PCR validation revealed their multifaceted roles in growth, development and stress responses. Overexpression of GhBBE59 (BBE7) in Arabidopsis enhanced Cd tolerance by 25 % marked by a 20% reduction in malondiadehyde (MDA) and 25 % higher superoxide dismutase (SOD) activity compared to wild type plants. While its knockdown in cotton, reduced Proline accumulation by 60 % and increased electrolyte leakage by 2 fold, rendering plants hypersensitity to Cd stress. Transcriptomic and biochemical analyses demonstrated that BBE7 modulates redox homeostasis via 25% higher glutathione accumulation and hormonal crosstalk, mitigating oxidative damage. Functional analyses further revealed the pivotal role of BBE7 in regulation of oxidative stress, antioxidant production, epigenetic modifications and proline accumulation, thereby enhancing stress resilience. These findings hold substantial promise for reducing cadmium accumulation in soils, thereby mitigating its entry into the food chain and associated health risks. The implications of current study extend beyond fundamental research, addressing real-world challenges associated with environmental stresses and sustainable agriculture practices by enabling safer cultivation in polluted environments.

Phytoremediation assisted by endophytic bacteria is a promising strategy to enhance the remediation efficiency of heavy metals in contaminated soil. In this study, the capacity and role of the endophytic Bacillus sp. D2, previously isolated from Commelina communis growing near a copper (Cu) mine, in assisting the phytoremediation were evaluated. Results showed that inoculation of Bacillus sp. D2 significantly enhanced the biomass production of C. communis by 131.06% under high level of Cu stress. Additionally, the oxidative damages caused by Cu toxicity in C. communis tissues were alleviated as evidenced by significant reductions in malondialdehyde (MDA), superoxide anion (O2 center dot-) and proline content following Bacillus sp. D2 inoculation. Meanwhile, the activities of antioxidant enzymes in plant leaves presented upward trends after Bacillus sp. D2 inoculation. Notably, Bacillus sp. D2 inoculation significantly decreased Cu uptake and translocation by C. communis, while enhancing the Cu stabilization in contaminated soils. Furthermore, soil enzyme activities (acid phosphatase, catalase, and urease), as well as the richness of soil bacterial communities in Cu-contaminated soil increased following Bacillus sp. D2 inoculation. Importantly, the inoculation specifically augmented the relative abundance of key bacterial taxa (including Pseudomonas and Sphingomonadaceae) in the rhizosphere soil, which was positively correlated with soil nutrients cycling and plant growth. Our findings suggest that the endophytic strain Bacillus sp. D2 can strengthen the phytostabilization efficiency of Cu by C. communis through its beneficial effects on plant physio-biochemistry, soil quality and bacterial microecology, which provides a basis for the relative application to Cu-contaminated soils.