International Journal of Phytoremediation最新文献

Green manure returning can improve soil fertility and crop production, and immobilize heavy metals in the soil. However, limited information is available on the effects of green manure replacing chemical fertilizers on soil properties and crop growth. In this study, we investigated the effects of Chinese milk vetch incorporation with reduced chemical fertilizers on soil properties, rice agronomic traits and cadmium (Cd) accumulation by field experiments, and four treatments were conducted: chemical fertilizer alone (CF), milk vetch alone (MV), milk vetch plus 80% chemical fertilizers (MVCF80), and milk vetch plus 50% chemical fertilizers (MVCF50). The results showed that all milk vetch treatments decreased soil pH and Eh, and increased the SOM, DOC contents and the activities of catalase and urease. The soil DTPA-Cd contents decreased by 20.41%, 18.20%, and 21.22%, and the Cd accumulation in rice root, stem, leaf, and grain decreased by 21.13%-37.62%, 20.74%-39.61%, and 21.91%-43.56% under MV, MVCF80, and MVCF50 treatments, respectively. Additionally, the MVCF80 treatment showed a better rice agronomic traits and grain yield than others. These data revealed the great potential of milk vetch incorporation with chemical fertilizer reduction in decreasing Cd accumulation in rice plants and improving rice quality and yield of Cd-contaminated paddy fields.

Anthropogenic activities have accelerated lead (Pb) accumulation across different trophic levels in the ecosystem. This study focused on the physiological mechanisms of an invasive plant, Alternanthera tenella in a controlled hydroponic setting to understand its response to Pb stress. A. tenella was exposed to 680 µM of lead acetate for 21 days, showing high tolerance (83%) with minimal growth inhibition. Pb exposure altered macro- and micronutrient concentrations, suggesting essential mineral reallocation to enhance stress tolerance. Scanning electron microscopy (SEM) revealed Pb²⁺ depositions in the vacuoles and cell walls of root (∼14%) and leaf (∼3%) cells, a key mechanism for reducing Pb toxicity. Fourier transform infrared spectroscopy (FTIR) indicated that Pb²⁺ ions interacted with hydroxyl (-OH) and amide (CO-NH) groups, important for metal ion complexation. Physiological responses included increased proline, malondialdehyde, protein degradation, and elevated catalase (CAT) and ascorbate peroxidase (POD) activity. A. tenella accumulated 46,866.92 mg/kg DW of Pb, primarily in roots (2682.5 mg/kg DW), with limited Pb translocation to shoots, suggesting a protective mechanism. High biological concentration (BCF 19.04) highlight its potential for Pb phytostabilization. These findings are specific to hydroponic conditions, and further research is needed to assess its phytoremediation potential in field conditions.

Rice is the staple food for 1/3 of the world's population, but soil pollution with cadmium (Cd) is harmful to rice production and human health. Therefore, how to reduce the Cd content in rice grains is a hot topic worldwide. However, so far, little is known about Cd remediation technologies for paddy soils from the perspective of patents. Therefore, a meta-analysis was performed to assess the effects of measures based on 1402 observations from 336 patents from 2011 to 2021. The spatio-temporal analysis showed that the number of patents was positively related to the general economic development of the country, but hardly related to the regional economy or the level of provincal Cd pollution. The meta-analysis showed that the overall effect of Cd reduction was slightly higher for combined technologies (59%) than for single technologies (57%). Among all technology classifications, soil applications, which are mainly based on nutritional elements, were the most commonly used technology that could reduce the Cd content in rice grains by 57%. The plant biotechnology was the most effective and could reduce Cd content in rice grains by 76%. Further analysis showed that macronutrients (calcium, phosphorus, and sulfur) were preferred in soil amendments, while micronutrients (silicon, zinc, and selenium) were preferred in foliar amendments. NRAMP5 and HMA3 were the most important genes for manipulating Cd uptake in rice, while Bacillus and Pseudomonas were the most important bacterial taxa for bioremediation of Cd. Overall, this study compiled data on Cd remediation of paddy soil from 10 years of Chinese patents, providing a theoretical basis for better production of low Cd crops and protection of human health.

Atmospheric particulate matter (PM) emission from overpasses is serious. To optimize the solution of planting design in the overpass, it is essential to understand the plant's ability to capture PM. In this study, leaf samples were collected from 11 plant species commonly existing in five overpass greening areas in Changsha, China. The PM retention per unit leaf area (M_leaf), PM retention on a unit greening land (M_land), and leaf surface microstructure were measured and analyzed. Results showed that the M_leaf of Ophiopogon japonicus (1.59 g/m²) exhibited the highest value, and that of Nandina domestica (0.23 g/m²) was the lowest value. The M_land of O. japonicus, Fatsia japonica, and Magnolia grandiflora was the highest based on the leaf area index. Leaves with wide gullies and cuticular wax significantly affected the PM retention ability of plants. Plant height played an important role in the PM retention ability in the overpass. Multilayered canopy structures such as arbor-shrub-herb had great potential for PM retention in overpasses. Based on the results, a PM retention design scheme of overpass greening space was proposed. This study provided an optimal solution for providing critical insights and guidance for developing effective PM reduction strategies in urban overpass environments.

Phytoremediation is an effective and sustainable method for removing pollutants from wastewater. This study investigates the phytoremediation capabilities of Limoniastrum guyonianum, a halophytic Saharan plant species, for excess phosphorus and nitrogen in domestic wastewater. The plants were sourced from the "Halloufa" wetland, a wastewater discharge area in the north of El-Oued, south-eastern Algeria. The research was conducted using pilot-scale circular beds designed for phytoremediation, each with an 18-liter capacity, filled with layers of gravel and a clay-sand mixture. These beds were part of a vertical surface flow system at the National Sanitation Office (ONA) domestic wastewater treatment facility in El-Oued, Algeria. The results demonstrated significant improvements in water quality parameters. Treatment with L. guyonianum reduced pH values from 8.07 to 7.64 and decreased turbidity from 116.25 NTU to 8.87 NTU. The mean concentration values of ammonia, phosphate, and biochemical oxygen demand (BOD₅) were reduced by 99.22%, 55.58%, and 78.6%, respectively. The study concludes that L. guyonianum is highly efficient in remediating nitrogen contaminants, effective in reducing phosphorus levels, and capable of lowering biochemical oxygen demand. L. guyonianum presents a nontoxic, eco-friendly, and cost-effective alternative for wastewater treatment in the "Halloufa" wetland, highlighting its potential for application in bioremediation processes.

Cadmium (Cd) has shown toxicity to reduce growth and productivity in different plants. The Present study investigated the efficacy of menadiol diacetate (MD) to reduce Cd stress on growth and yield of summer squash plants. The experiment was performed under saturated Hoagland's nutrient solution (control) while the other group was supplemented with 0.1 mM CdCl₂ (Cd stress). Surface sterilized seeds of summer squash were primed in different concentrations (10, 20 µM) of MD as well as in distilled water for 24 h and sown in the pots. Different morphological and physio-biochemical attributes were determined after 35 d of growth whereas the data for yield attributes was collected after 70 d. Cd concentration was determined in various subcellular compartments i.e., cell walls and cell wall debris, chloroplast, cell membrane and other organelles including vacuoles. The Cd stress decreased photosynthetic pigments, osmoprotectants and ultimately caused reduction in the yield attributes. Further, it increased the secondary metabolites and oxidants (MDA and H₂O₂) in the summer squash tissues. Cd exposure also altered ions accumulation in the summer squash tissues by increasing the root and shoot Ca²⁺ (24-93%) and Fe (4-18%) ions while decreasing the Mg²⁺ (31-39%) ions. The MD-priming, particularly at 10 µM concentration mediated increase in the total phenolics, ascorbic acid, and anthocyanins concentration, and thus enhanced growth and yield attributes of summer squash exposed to Cd toxicity. Further, 10 µM MD-priming facilitated Cd compartmentalization in the subcellular compartments mainly in the cell wall (58%) rather than in the chloroplast (18%), cell membrane (7%) and soluble fractions (18%). In this context, cell wall and vacuole were the key compartments for Cd sequestration. This study highlights MD-priming as a potential strategy to counter Cd toxicity in summer squash plants.

The concurrently occurring multiple abiotic stresses like salinity and heavy metals (Nickel) pose a serious threat to plant survival and food security worldwide, especially in the face of climate change. Therefore, it is imperative to continuously test and study the plant's physiological changes under combinations of abiotic stresses to ensure sustainability and food security. An experiment was conducted to study the interactive effects of salinity (0, 7.5, and 15 dS m^-1) and Ni toxicity (0, 10, 20, and 40 mg kg^-1) on a tolerant (Naqeeb) and a sensitive (Nadir) Solanum lycopersicum L. physiology and fruit quality in the soil. At maturity (50% fruit ripening), the plant growth and physiological characteristics were measured, revealing that the tolerant genotype exhibited the higher values for plant height, dry weight, potassium, membrane stability index (MSI), and antioxidant enzymes (superoxide dismutase; SOD, catalase; CAT, ascorbate peroxidase; APX, and glutathione reductase; GR). Additionally, it showed enhancement in fruit yield, size, and quality. Conversely, the tolerant genotypes showed a lower reduction in terms of plant height (25.4%) and plant dry weight (41.9%) compared to sensitive genotype (30.1 and 51.4%, respectively). Additionally, the tolerant genotype demonstrated lower values of Ni and Na⁺ concentration and MDA accumulation under the combined stress of salt and Ni, compared to the sensitive genotype. Furthermore, the study indicated that Ni at a concentration of 10 mg kg^-1 significantly influenced tomato plant growth by enhancing its nutritional efficiency and competing with Na⁺. However, Ni at concentrations of 20 and 40 mg kg^-1 had toxic effects on the plants, leading to a decrease in plant growth and physiological processes. Moreover, a negative relationship was observed between Ni uptake and Na⁺ uptake, while a positive relationship was observed between Ni and K⁺ uptake. Overall, this study provides valuable insights into the interaction between salinity, heavy metal toxicity, and tomato plant physiology, contributing to the development of sustainable agricultural practices.

Heavy metals toxicity in soil is increasing globally and bioremediation of these contaminants through sustainable and recalcitrant materials has gained attention in recent years. A greenhouse pot experiment was conducted to investigate the effect of Cr tolerant Bacillus subtilis and Pseudomonas aeruginosa strains along with biochar of different feedstocks on maize plant biochemical attributes and soil health. Results of the study revealed that Cr contamination decreased plant growth attributes whilst the integrated application of B. subtilis+PLB significantly improved root-shoot length (36 and 10% respectively), total chlorophyll (11.29%), and stomatal conductance (11.95%). Under Cr contamination, maize carotenoid, flavonoid, and phenolic contents also improved up to 77.20%, 39.18%, and 7.90% respectively by B. subtilis+PLB treatment. Soil PLFA content, G+, G-, Fungi and actinomycetes activity also alleviated along with antioxidants superoxidase (54%), peroxidase (28.57%), and catalase (89%) under the treatment of B. subtilis+PLB. Additionally, microbial CUE improved up to 70% under B. subtilis+PLB followed by P. aeruginosa+PLB (62%). Moreover, soil nutrient content (TOC, N, P, and K) also showed a great improvement under the combinedcombined application of PGPR and biochar. These findings of the study provide a sustainable solution for the bioremediation of Cr in agricultural soil by improving soil microbial and antioxidative activities.

Adsorption is one of the most efficient ways to eliminate hazardous metals. The study evaluated the effectiveness of banana peel biochar as a cheap adsorbent to remove hazardous metals from landfill leachate. The landfill leachate of 100 mg/L was mixed with banana peel biochar (0.50, 1.50, and 3.00 g each) and placed in a water bath for 15, 30, and 45 min at a constant temperature of 30 °C and 35 °C. The adsorption efficiency of banana peel biochar for nickel in the leachate ranged from 98.76% to 98.96% and chromium ranged from 99.71% to 99.77% at a temperature of 30 °C for 15 mins and 99.07% to 99.27% for Ni and 99.71% to 99.73% for Cr at a temperature of 35 °C for 45 min. Banana peel biochar maximum adsorption capacity of nickel ranged from 1.15 × 10^-5 mg/g to 5.27 × 10^-6 mg/g, and 1.05 × 10^-5 mg/g to 6.76 × 10^-6 mg/g for chromium. Adsorbent made from less expensive banana peel can affordably remove nickel and chromium from landfill leachate. To acquire a broad understanding of the adsorbent's application, more adsorptive research utilizing banana peels as an adsorbent to treat various wastes ought to be conducted.

The photosynthetic pigments, antioxidant properties, and heavy metal content in Reseda lutea, Epilobium dodonaei, and Gentianella ciliata were examined in response to stress in the open pit of an abandoned iron mine. The soils were shallow, alkaline, and severely deficient in phosphorus, potassium, and humus. Heavy metal concentrations in the rhizospheres followed the order Fe > Mn > Pb > Zn > Cu > Ni > Cr > Cd for all three species, with Cu, Zn, and Pb exceeding the limits established by Bosnian legislation. The results indicated that the bioelements Cu, Zn, and Mn were within permissible limits set by FAO/WHO. Epilobium dodonaei acted as a Cd accumulator. The highest content of photosynthetic pigments was observed in this species. Positive correlations were detected between Cr and total phenolics, Cr and total flavonoids in E. dodonaei, Pb and total phenolic acids in G. ciliata. Negative correlations were noted between Zn and total phenolic acids in R. lutea, and Fe and total phenolics in E. dodonaei. Increased total proline and DPPH concentrations were associated with heightened Fe levels in E. dodonaei. These findings suggest that the species analyzed employ distinct defense mechanisms, enabling them to effectively adapt to stress.