International Journal of Phytoremediation最新文献

Arsenic in groundwater is a severe problem in México, where its concentration in drinking water exceeds the limit established by the World Health Organization's reference value, and represents a public health problem in the San Luis Potosí, where the affected populations live in semiarid areas without access to arsenic reduction technologies. We developed transgenic Chlamydomonas reinhardtii strains by nuclear and plastid transformation using genes arsC, ɣ-ecs, and acr3 as a cost-effective and noninvasive phytoremediation strategy. The capacity to remove arsenic was evaluated under diverse As(V) concentrations (0.5-2 mg/L) and two phosphate levels (375 and 37.5 µM). The plastid and the double-recombinant strains exhibited substantial As(V) removal capabilities, with a 20% and 80% increase versus wild-type (WT) strain, at the lowest phosphate concentration, the double-recombinant strain exhibited an arsenic uptake rate up to 12 times higher than that of the wild-type (WT) strain, indicating that the genetic modifications enhanced arsenic removal. The double-recombinant microalgae demonstrated exceptional tolerance to As(V), maintaining a µ_max value comparable to that of other strains, indicating sustained cell growth under arsenic stress. This strategy offers a viable platform for arsenic phytoremediation and holds promise for future implementation in public-scale systems.

In this study, ZnO nanoparticles with a size of 192 nm were produced via green synthesis using Diospyros kaki L. peel extract and were characterized by energy-dispersive X-ray analysis (EDAX), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-Visible spectroscopy, dynamic light scattering (DLS), Brunauer-Emmett-Teller (BET), and zeta potential (ZP) analysis. The produced nanoparticles were tested for photocatalytic degradation of methylene blue and optimized using the Box-Behnken design. Under optimum conditions (pH: 10, dye concentration: 10 ppm and catalyst amount: 0.13 g and pH: 7, dye concentration: 10 ppm and catalyst amount: 0.6 g), 100% dye removal was achieved in 270 min and the model was validated by ANOVA. This study represents the first investigation involving the production and photocatalytic application of nanoparticles synthesized using D. kaki peel.

In the current study, we synthesized nano zinc sulfide (nZnS) and studied the effects of root zone (RZ) and foliar application (FS) of nZnS (0 and 50 mg/L) on cadmium (Cd) stressed maize (0 and 1 mM CdCl₂) using completely randomized design (CRD). After 20 d of nZnS supplementation, growth and biochemical responses were recorded. The study highlights the critical issue of Cd stress in maize and investigates how nZnS influences plant tolerance mechanisms. We explored the novelty of application of RZ and FS of nZnS, focusing on its role in Cd/Zn homeostasis, growth and stress resilience. The RZ supplementation with nZnS recovered growth and enhanced maize protein and phenolic content under Cd stress. Exogenous application of nZnS improved chlorophyll under Cd stress. Whereas, exposure to Cd stress markedly reduced Zn in shoots (0.0015 mg/g DW; -99.1%) compared to the control (0.186 mg/g DW). The nZnS application enhanced Zn fraction in shoots (2.03 mg/g DW by RZ; and 1.46 mg/g DW by FS), especially in Cd-stressed plants (2.68 mg/g DW by RZ; and 2.36 mg/g DW) by FS. Exposure to Cd stress resulted in an increased shoot Cd fraction (0.376 mg/g DW), which was further increased by root zone nZnS supply (0.673 mg/g DW; +44.0% compared to Cd-stressed plants. Foliar application of nZnS also enhanced the Cd concentration in the shoots (0.579 mg/g DW; +35.0% compared to the Cd-stressed plants). Although the Cd fraction was synergistically increased due to nZnS supply which can be explained based on Cd/Zn homeostasis reinforced by sulfur (S) supply. In conclusion, the use of nZnS alleviated Cd stress in maize, suggesting that it is an effective strategy for improving Cd tolerance in crops like maize.

Biochar has great potential as an adsorbent for heavy metal ions, and predicting its adsorption performance using machine learning algorithms is a promising research area. This study employs two machine learning methods, lightweight gradient boosting machine (LightGBM) and deep neural network (DNN), to establish predictive models for the removal rates of Pb²⁺ and Cd²⁺ by biochar. The dataset for Pb²⁺ and Cd²⁺ contains 419 and 240 samples, respectively. Shapley Additive Explanations (SHAP) values are also used to analyze the role of functional groups in the adsorption of heavy metal ions. By comparing two input feature combinations (with/without elemental analysis), it was found that adding elemental analysis can improve the prediction accuracy of Pb²⁺ removal rate. Specifically, the R² of the LightGBM model increased from 0.920 to 0.923, and the MAE and RMSE were reduced by 0.761 and 0.641, respectively. However, the inclusion of elemental analysis showed little change in the prediction accuracy of Cd²⁺ removal rate. This study provides valuable insights for predicting biochar's adsorption of other heavy metal ions and further explains that different functional groups influence the adsorption performance of various heavy metal ions differently.

This study investigates whether plants can uptake, accumulate, and detoxify polycyclic aromatic hydrocarbons (PAHs), hazardous pollutants that can harm soil fertility and the environment. To test this hypothesis, hydroponic system was used to examine the distribution dynamics and potential degradation pathways of pyrene (PYR) in proso millet (Panicum miliaceum) tissues at varying concentrations (0, 500, 1,000, 1,500, and 2,000 ppm). Results indicated that higher PYR concentrations adversely affected plant growth, but plant-assisted dissipation removed 29-43% of PYR over 30 days. While PYR levels in the roots increased with exposure, concentrations in the shoots significantly decreased at higher PYR levels. By the end of the experiment, PYR concentrations were higher in roots than in shoots. Bioconcentration and translocation factors peaked at 500 ppm, with translocation to shoots evident on day 15 but primarily restricted to roots by day 30. Furthermore, three main steps in PYR degradation in P. miliaceum were proposed: (A) ring cleavage and oxidation reactions forming epoxides, (B) enzymatic transformations of epoxides and other intermediates, and (C) synthesis of terpenoids and phthalates.

Lead (Pb) is a common environmental contaminant that poses a significant threat to plant growth and productivity. Gibberellic acid (GA₃), a phytohormone, is recognized for its role in promoting growth and alleviating abiotic stress. This study aimed to evaluate the effectiveness of foliar GA₃ in mitigating Pb toxicity in two brinjal varieties (round and long). Conducted in February 2023 at the experimental area of Govt. College Women University, Faisalabad, the experiment involved planting ten seeds of each variety in pots, using a completely randomized design (CRD) with three replicates. Treatments included Pb at 100 and 150 mg/kg, GA₃ at 25 mg/L, and a control group. Results indicated that Pb treatment significantly reduced shoot and root length, fresh and dry weight, total soluble sugars, proteins, malondialdehyde (MDA), phenolics, carotenoids, and anthocyanins. However, the application of GA₃ (25 mg/L) effectively mitigated the negative effects of Pb, with more pronounced benefits observed in the round variety compared to the long variety. Principal component analysis (PCA) confirmed that independent GA₃ treatment led to improved growth in the round variety when subjected to Pb stress.

Melatonin (MT) is a natural, multifunctional molecule with amphiphilic properties, enabling it to cross cellular membranes rapidly, and it also contributes to plant resistance against abiotic stresses. However, the possible complex mechanisms by which MT mitigates salt toxicity and oxidative damage in cauliflower (Brassica oleracea L.) remain unclear. To fill this gap and clarify the pathway to salt stress resistance, the present study investigated the effects of exogenous 50 μM MT on growth, physiological, biochemical, and phyto-hormonal responses of cauliflower seedlings subjected to 200 mM NaCl-induced salinity stress. Our results revealed that salinity stress triggered a significant reduction in leaf and root biomass, chlorophyll and carotenoid pigments, gas exchange parameters, and K⁺ and Mg²⁺ ions indicators, while Na⁺ levels and hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) concentrations were significantly elevated, suggesting that cauliflower plants were adversely affected by salt-induced oxidative stress. However, exogenous MT application alleviated the reductions in growth, biochemical parameters, and physiological functions, promoting melatonin content and reducing reactive oxygen species (ROS) accumulation and lipid peroxidation by enhancing photosynthetic efficiency and promoting the accumulation of osmoprotectants under salt stress. Moreover, MT suppressed salt-induced oxidative stress by declining oxidative indicators via enhancing antioxidants activities such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) enzymes as well as significantly increasing abscisic acid (ABA) levels in the leaves of cauliflower plants under saline stress. In conclusion, we propose that exogenous MT application significantly enhances the physiological and biochemical profiles of cauliflower plants by improving organic osmolytes and mitigating salt-induced oxidative stress. Likewise, the correlation analysis presented strong evidence and confirms a direct contribution of MT+NAA in the growth, physio-biochemical, and phyto-hormonal traits under severe saline stress. This finding suggests that exogenous melatonin application could offer valuable strategies for cauliflower cultivation in saline environments.

This study investigated the regulatory mechanism of exogenous Jasmonic acid (JA) in detoxifying Cu stress in guinea grass (Panicum maximum). Seedlings were treated with Cu (300 µM), JA (10 µM), and their combinations via Hoagland solution in controlled growth chambers for 30 days. The results indicated that Cu stress significantly reduced superoxide dismutase (-51.2%) and peroxidase (-38.0%), chlorophyll content, net photosynthetic rate (Pn), and led to decreases in leaf length, width, plant height, and biomass (-49.7%). Conversely, exogenous JA effectively mitigated the adverse effects of Cu stress by reducing membrane damage, and increasing chlorophyll, Pn (+107%), and antioxidant enzymes (p < 0.05), and biomass (+84.7%), modifying associated metabolites. A total of 63 metabolites with differential accumulations were identified when exposed to JA, Cu, or their combination, mainly including amino acids, organic acids, and carbohydrates. Excessive Cu significantly reduced the levels of capric acid, salicylic acid, and glucosaminic acid, while increasing malic acid and serine content, which are primarily involved in regulating the citrate cycle and alanine-aspartate and glutamate metabolism. Overall, these findings demonstrates that guinea grass alleviates Cu toxicity by enhancing photosynthetic efficiency, antioxidant enzyme activity, and modifying associated metabolites and pathways under JA, thereby exhibiting potential for phytoremediation of Cu stress.

The Chernobyl Nuclear Power Plant (CNPP) disaster in 1986 released significant amounts of radiocesium (¹³⁷Cs), radiostrontium (⁹⁰Sr), and radioiodine (¹³¹I) across Europe and eastern areas of Russia, leading to widespread environmental contamination that negatively impacted human health and harmed flora and fauna in a variety of terrestrial and aquatic ecosystems. The long-term effects of the Chernobyl incident remain a persistent concern, particularly due to radiocesium which has a half-life of 30.17 years, and various environmental and human-driven events that continue to resuspend radionuclides into the environment. Nearly four decades after the incident, various remediation efforts have been implemented, including physical, chemical, and biological approaches. However, no method has proven to be completely effective, and the significant remaining contamination necessitates the implementation of new strategies for remediation. Some of the most promising remediation techniques fall under the science of bioremediation; the use of bacteria, algae, fungi, and plants to remove contaminants from the environment. Phytoremediation is promising due to its environmentally friendly nature and its cost. This review article examines the environmental impacts of the Chernobyl fallout, evaluates remediation efforts over the past four decades, and explores emerging phytoremediation strategies that could enhance radionuclide removal from contaminated terrestrial and aquatic environments.

The green synthesis method is a significant approach that offers several advantages, including simplicity, rapidity, and cost-effectiveness in the synthesis of nanoparticles. Iron nanoparticles were synthesized in this work using waste banana peel extract as a capping and reducing agent. The produced nanoparticles were then subjected to a number of characterization procedures, such as Raman spectroscopy, X-ray diffractometry (XRD), zeta potential analysis, Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible (UV-VIS) absorption spectroscopy, field scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDX), and thermogravimetric analysis (TGA). The effect of the nanoparticles on dye elimination was next investigated separately and with the aid of ultrasound irridation. To ascertain the efficacy of the nanoparticles, their performance was compared with that of the classical Fenton process. The results showed that 99.7% of the dye was removed within 60 min with a 10 mg/L iron concentration, 10 mg/L hydrogen peroxide (H₂O₂) concentration, and 53 kHz ultrasound radiation. In FeNPs reuse, 91% efficiency was achieved in the 2nd cycle, 56% in the 3rd cycle and 51.37% in the 4th cycle.