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A cost-effective adsorbent (AWS@Zr) was synthesized from walnut shell using Zirconium and amino group modification for the uptake of 2,4-dichlorophenoxyacetic acid (2,4-D) and phosphate (PO43−). Characterization of the adsorbents revealed a significant difference in the physicochemical parameters of pristine and functionalized walnut shell. Langmuir model was observed to predict adsorption of 2,4-D, while Freundlich model best-fitted PO43− adsorption with chemisorption being the principal underlying mechanism. The adsorption phenomena were pH dependent with Langmuir maximum capacity of 227.4 ± 5.4 mg g−1 and 73.9 ± 3.2 mg g−1 for 2,4-D and PO43−, respectively. Kinetic models were also used to analyze the experimental data, and remarkable determined coefficients favor the pseudo-second-order kinetic model for the batch systems. The column experiments were carried out as a function of adsorbates flow rate, initial feed of 2,4-D and PO43− concentration, bed depth. The results indicated both Thomas and Clark models could predict uptake of 2,4-D and phosphate with Thomas maximum capacity as 195.5 ± 1.0 for 2,4-D and 87.4 ± 0.7 mg g−1 for PO43− at optimum flow rate of 10 mL min−1 and bed depth of 6 cm. Moreover, the column isotherm studies revealed that the Langmuir model predicted the adsorption data of PO43−, and 2,4-D, which was consistent with batch adsorption of 2,4-D. The studied pollutants onto AWS@Zr are PO43− > 2,4-D based on the β−1 obtained from the column's mass transfer analysis. Adsorption–desorption studies revealed the reusability potentials of AWS@Zr. Zr and amino in surface of AWS@Zr play major role during removal of 2,4-D and PO43−. There is potential for AWS@Zr to remove some anionic pollutants from solution. [ABSTRACT FROM AUTHOR]

Anaerobically digested sludge-derived biochar was produced through pyrolysis at 700 °C, called BC700. BC700 was characterized using a scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier-transform infrared spectroscopy (FTIR), and the Brunauer–Emmett–Teller (BET) method. The factors influencing the adsorption process and the mechanism involved in adsorbing tricyclazole and 2,4-D in single and binary systems were revealed. The theoretical maximum adsorption capacities of BC700 for tricyclazole and 2,4-D in a single system were 11.86 mg/g and 7.89 mg/g, respectively. In the binary system, the theoretical saturated adsorptive capacities of tricyclazole and 2,4-D were 5.27 mg/g and 3.20 mg/g, respectively. The adsorption of tricyclazole and 2,4-D by BC700, whether in single or binary systems, matched closely with the Freundlich isotherm and the pseudo-second-order model. This study indicates that anaerobically digested sludge-derived biochar is potentially valuable for removing pesticide contamination in surface water. [ABSTRACT FROM AUTHOR]

The present study presents the results obtained from evaluating the photocatalytic behavior of a series of sulfated CeO2 materials in the photocatalytic degradation of the herbicide 2,4-dichlorophenoxyacetic acid. The CeO2 photocatalytic support was prepared using the precipitation synthesis method. Subsequently, the support was wetly impregnated with different contents of sulfate ions (0.5, 1.0, and 2.0 wt.%). The materials were characterized using X-ray diffraction, nitrogen physisorption, infrared spectroscopy, diffuse reflectance UV–Vis spectrophotometry, and thermal analysis. The characterization results showed that the sulfation of the material promoted an increase in the surface area and a decrease in the average size of the crystallites. Likewise, it was possible to demonstrate the surface sulfation of the support through bidentate coordination of the sulfate groups to the semiconductor metal. Concerning photoactivity, the convenience of the surface modification of CeO2 was confirmed because the sulfate groups acted as capturers of the electrons generated during the photocatalytic process, reducing the frequency of recombination of the charge carriers and allowing the availability of the gaps to favor the degradation reaction of the contaminant. Finally, it was evident that a percentage of 1.0 wt.% of the sulfate anion is the optimal content to improve the photocatalytic properties of CeO2. [ABSTRACT FROM AUTHOR]

The commercialization of 2,4‐D (2,4‐dichlorophenoxyacetic acid) latifolicide in 1945 marked the beginning of the selective herbicide market, with this active ingredient playing a pivotal role among commercial herbicides due to the natural tolerance of monocots compared with dicots. Due to its intricate mode of action, involving interactions within endogenous auxin signaling networks, 2,4‐D was initially considered a low‐risk herbicide to evolve weed resistance. However, the intensification of 2,4‐D use has contributed to the emergence of 2,4‐D‐resistant broadleaf weeds, challenging earlier beliefs. This review explores 2,4‐D tolerance in crops and evolved resistance in weeds, emphasizing an in‐depth understanding of 2,4‐D metabolic detoxification. Nine confirmed 2,4‐D‐resistant weed species, driven by rapid metabolism, highlight cytochrome P450 monooxygenases in Phase I and glycosyltransferases in Phase II as key enzymes. Resistance to 2,4‐D may also involve impaired translocation associated with mutations in auxin/indole‐3‐acetic acid (Aux/IAA) co‐receptor genes. Moreover, temperature variations affect 2,4‐D efficacy, with high temperatures increasing herbicide metabolism rates and reducing weed control, while drought stress did not affect 2,4‐D efficacy. Research on 2,4‐D resistance has primarily focused on non‐target‐site resistance (NTSR) mechanisms, including 2,4‐D metabolic detoxification, with limited exploration of the inheritance and genetic basis underlying these traits. Resistance to 2,4‐D in weeds is typically governed by a single gene, either dominant or incompletely dominant, raising questions about gain‐of‐function or loss‐of‐function mutations that confer resistance. Future research should unravel the physiological and molecular‐genetic basis of 2,4‐D NTSR, exploring potential cross‐resistance patterns and assessing fitness costs that may affect future evolution of auxin‐resistant weeds. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The possibility of reusing mesoporous Sibunit as an adsorbent for 2,4-dichlorophenoxyacetic acid was studied. The effectiveness of using microwave radiation to restore the adsorption properties of the studied adsorbent was shown. A decrease in the average pore size on the surface of the Sibunit sample was noted as the adsorption–regeneration cycles were carried out without reducing the value of the adsorption capacity. [ABSTRACT FROM AUTHOR]

In this study, an adsorbent based on waste peanut husks was synthesized. To facilitate the easy removal and efficiency of these peanut husks, it was first endowed with magnetic properties via the coprecipitation method after which NH2-MIL-101 (Fe) was loaded onto the magnetized peanut husks. This magnetic biomass-MOF composite (MPN@NH2-MIL-101 (Fe)) was used for the removal of 2,4-dichlorophenoxyacetic acid (2,4-D) and tetracycline (TC) in single and binary systems. MPN@NH2-MIL-101 (Fe) was found to be a crystalline magnetic adsorbent with a mesoporous structure with a surface area of 70.5 m2 g−1, pH point of zero charge of about 4.05, and possesses oxygen and nitrogen atoms containing functional groups which promoted its interactions with the studied pollutants leading to their uptake. Owing to the nature of these contaminants, the interactions that occurred in these adsorption processes were found to be dominated by both chemisorption and physisorption mechanisms. The monolayer adsorption capacity of MPN@NH2-MIL-101 (Fe) towards 2,4-D and TC was found to be 79.2 ± 8.3 and 109 ± 3.76 mg g−1 according to the Langmuir model, respectively. In binary systems, MPN@NH2-MIL-101 (Fe) had a higher selectivity towards 2,4-D which could be due to its smaller size in comparison with TC signifying the role of intraparticle diffusion. These excellent features of MPN@NH2-MIL-101 (Fe) coupled with its stability in aqueous solution and ease associated with its removal may enhance its prospects as an alternative adsorbent for practical applications. [ABSTRACT FROM AUTHOR]

Yam (Dioscorea sp.) is an important staple crop for millions of smallholder farmers in West Africa. In this study, we aimed to develop an efficient indirect plant regeneration system for three important yam genotypes "Kukrupa," "Mankrong Pona" and "Matches." The potential of leaf primordia, petioles and axillary bud explants for callus induction on Murashige and Skoog (MS) medium supplemented with different concentrations (0, 3, 5, 7 and 9 mg/l) of 2,4-dicholorophenoxy acetic acid (2,4-D) or picloram were tested. Callus induction was influenced by auxin concentration as well as explant. The highest callus induction was achieved using leaf primordia ("Kukrupa" and "Mankrong Pona") explants on 3 mg/l picloram or axillary buds ("Matches") on 5 mg/l picloram. Transfer of callus to 6-benzylaminoapurine (BAP) amended medium resulted in the formation of at least two shoots per callus clump. Plantlets were obtained on basic yam medium supplemented with 0.2 mg/l 1-naphthalene acetic acid (NAA), 3 mg/l kinetin and 0.5 mg/l BAP after four weeks. Post acclimatization plantlet survival was high (75 − 82.5%). The indirect plant regeneration protocol reported through this study helps in the improvement of important yam genotypes through tissue culture-oriented genome editing, in vitro mutagenesis and also for its mass propagation. [ABSTRACT FROM AUTHOR]

The development of highly efficient and stable visible-light-driven photocatalysts for the removal of herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) from water is still a challenge. In this work, Bi2MoO6 (BMO) materials with different morphology were successfully prepared via a simple hydrothermal method by altering the solvent. The morphology of the BMO material is mainly influenced by the solvent used in the synthesis (H2O, ethanol, and ethylene glycol or their mixtures) and to a lesser extent by subsequent thermal annealing. BMO with aggregated spheres and nanoplate-like structures hydrothermally synthesized in ethylene glycol (EG) and subsequently calcined at 400 °C (BMO-400 (EG)) showed the highest adsorption capacity and photocatalytic activity compared to other synthesized morphologies. Complete degradation of 2,4-D on BMO upon irradiation with a blue light-emitting diode (LED, λmax = 467 nm) was reached within 150 min, resulting in 2,4-dichlorophenol (2,4-DCP) as the main degradation product. Holes (h+) and superoxide radicals (⋅O2−) are assumed to be the reactive species observed for the rapid conversion of 2,4-D to 2,4-DCP. The addition of H2O2 to the reaction mixture not only accelerates the degradation of 2,4-DCP but also significantly reduces the total organic carbon (TOC) content, indicating that hydroxyl radicals are crucial for the rapid mineralization of 2,4-D. Under optimal conditions, the TOC value was reduced by 84.5% within 180 min using BMO-400 (EG) and H2O2. The improved degradation performance of BMO-400 (EG) can be attributed to its particular morphology leading to lower charge transfer resistance, higher electron–hole separation, and larger specific surface area. [ABSTRACT FROM AUTHOR]

We face significant environmental pollution problems due to various industries, such as the aluminum industry, which generates large amounts of red mud (RM) waste, or agriculture, in which case the use of pesticides creates huge water pollution problems. In this context, the present study offers a better perspective to originally solve both environmental issues. Thus, the main target of the study referred to using RM waste as a filler for preparing composite copolymer beads. Thereafter, this can achieve significant removal of water pollutants due to their adsorption/oxidation characteristics. As evidenced by the changes in chemical structure and composition, thermal stability, morphology, and porosity, RM was homogenously incorporated in poly(acrylonitrile-co-acrylic acid) beads prepared by wet phase inversion. The final assessment for the removal of pesticides by adsorption and oxidation processes was proven successful. In this regard, 2,4-dichlorophenoxyacetic acid was chosen as a model pollutant, for which an adsorption capacity of 16.08 mg/g composite beads was achieved. [ABSTRACT FROM AUTHOR]

A method for obtaining effervescent tablets, consisting of magnetic carbon, tartaric acid, sodium carbonate and sodium bicarbonate, and their use for the adsorption of dichlorophenoxycarboxylic acids (DCPA)—2,4-dichlorophenoxyacetic, 2,4-dichlorophenoxypropionic and 2,4-dichlorophenoxybutyric acids and their metabolites—2,4-dichlorophenol and 4-chlorophenol is proposed. The tablets are immersed in an analyzed solution with a neutral reaction medium. To analyze soils, extraction with an alkali solution followed by the neutralization of the extract is carried out. After CO2 separation is completed, the sorbent is removed with a neodymium magnet and the analytes are desorbed with acetone. The acetone extract is evaporated under a stream of nitrogen, and the concentrate is analyzed by gas chromatography–mass spectrometry. The method was tested on model systems—samples of river water and typical chernozem, which were artificially contaminated with DCPA and chlorophenols (CP). In analyzing river waters, the limits of determination for DCPA are 0.7–0.9 μg/L, for CP—40 ng/L. In soils, the limit of detection is 3–4 and 0.1 μg/kg for DCPA and CP, respectively. [ABSTRACT FROM AUTHOR]

Compounds of three types, [LnL3(C2H5OH)] (Ln = Nd (I), Sm (II), Eu (III)), [LnL3(H2O)] (Ln = Gd (IV), Tb (V)), and [DyL2(NO3)(C2H5OH)2] (VI), were obtained by reactions of lanthanide nitrate with NaL (L– = 2,4-dichlorophenoxyacetate anion) in ethanol. The composition and structure of complexes I–VI were investigated by elemental and thermogravimetric analysis, IR spectroscopy, and X-ray diffraction (nos. 2311578 (I), 2311579 (II), 2311580 (III), 2311581 (IV), 2311582 (VI)). All compounds have a one-dimensional polymer structure in which metal atoms are connected by bridging carboxylate groups. The π–π interactions and intermolecular contacts between the chains give rise to a three-dimensional supramolecular structure. [ABSTRACT FROM AUTHOR]

The narrow band gap and rapid recombination rate of photogenerated carriers in CuBi2O4 limits the photocatalytic performance. Because it possesses unique properties such as up-conversion photoluminescence (PL) and in-plane quantum confinement effect, graphitic carbon nitride quantum dots (CNQDs) have outstanding application prospects in many fields. By combining solid-phase, coprecipitation and reconstruction methods, a new Z-scheme CNQDs/CuBi2O4 photocatalyst was successfully fabricated. The Box–Behnken design was optimized to study the complex interaction between reaction parameters. The CNQDs percentage in the catalyst, reaction time, 2,4-Dichlorophenoxyacetic acid (2,4-D) concentration, catalyst dose, and pH were varied from 0 to 2%, 90 to 120 min, 30 to 40 mg/L, 0.5 to 1.5 g/L, and 2.0 to 7.0, respectively, to maximize the 2,4-D removal efficiency after exposure to visible light. The following reaction parameters led to the highest photocatalytic removal efficiency: 1.0% of CNQDs, 110 min of reaction time, 33.0 mg/L of 2,4-D, 1.0 g/L of CNQDs/CuBi2O4, and a pH of 4.78. The predicted efficiency of 94.34% was very close to the experimental efficiency of 92.35%, which confirmed the accuracy of the design. The excellent activity of the CNQDs(1%)/CuBi2O4 catalyst in the photocatalytic degradation of 2,4-D is due to the enhanced charge separation efficiency and improved light absorption in the Z-scheme heterojunctions. Additionally, CNQDs(1%)/CuBi2O4 can be recycled with outstanding stability over four consecutive cycles. Superoxide radical (•O2−) and photoinduced hole (h+) play major roles, while the hydroxyl radical (OH•) plays a minor role in the photodegradation process. This study demonstrates that the design of the heterojunction is effective in achieving superior photocatalytic performance. The newly-developed Z-scheme CNQDs(1%)/CuBi2O4 photocatalyst is a promising visible-light catalyst for the decomposition of organic pollutants. [ABSTRACT FROM AUTHOR]

Adsorption of herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), on active carbon samples based on cedar nut shell (CN) was studied. The textural characteristics of CN, adsorption capacity, and kinetics of 2,4-D adsorption from an aqueous medium were studied. The activation of CN in a water vapor was shown to result in the formation of a developed microporous structure providing a high adsorption capacity of the carbon with respect to 2,4-D. [ABSTRACT FROM AUTHOR]

SUMMARY: Plant genome editing and propagation are important tools in crop breeding and production. Both rely heavily on the development of efficient in vitro plant regeneration systems. Two prominent regeneration systems that are widely employed in crop production are somatic embryogenesis (SE) and de novo shoot regeneration. In many of the protocols for SE or shoot regeneration, explants are treated with the synthetic auxin analog 2,4‐dichlorophenoxyacetic acid (2,4‐D), since natural auxins, such as indole‐3‐acetic acid (IAA) or 4‐chloroindole‐3‐acetic acid (4‐Cl‐IAA), are less effective or even fail to induce regeneration. Based on previous reports that 2,4‐D, compared to endogenous auxins, is not effectively exported from plant cells, we investigated whether efflux inhibition of endogenous auxins could convert these auxins into efficient inducers of SE in Arabidopsis immature zygotic embryos (IZEs). We show that natural auxins and synthetic analogs thereof become efficient inducers of SE when their efflux is transiently inhibited by co‐application of the auxin transport inhibitor naphthylphthalamic acid (NPA). Moreover, IZEs of auxin efflux mutants pin2 or abcb1 abcb19 show enhanced SE efficiency when treated with IAA or efflux‐inhibited IAA, confirming that auxin efflux reduces the efficiency of Arabidopsis SE. Importantly, in contrast to the 2,4‐D system, where only 50–60% of the embryos converted to seedlings, all SEs induced by transport‐inhibited natural auxins converted to seedlings. Efflux‐inhibited IAA, like 2,4‐D, also efficiently induced SE from carrot suspension cells, whereas IAA alone could not, and efflux‐inhibited 4‐Cl‐IAA significantly improved de novo shoot regeneration in Brassica napus. Our data provides new insights into the action of 2,4‐D as an efficient inducer of plant regeneration but also shows that replacing this synthetic auxin for efflux‐inhibited natural auxin significantly improves different types of plant regeneration, leading to a more synchronized and homogenous development of the regenerated plants. Significance Statement: It has been a longstanding question why the synthetic auxin 2,4‐dichlorophenoxyacetic acid (2,4‐D) is so effective in inducing plant regeneration. Here we show that the secret lies in its inefficient export from plant cells and that using natural auxins can be as effective, even leading to improved regeneration, when their efflux is transiently inhibited. [ABSTRACT FROM AUTHOR]

The effect of the simultaneous presence of fluoride (0.15–1.2 mg L−1), bicarbonates (83.6–596 mg L−1), and synthesized goethite (0.3 mg L−1) at typical concentrations often found in groundwater samples was evaluated on the degradation of 2,4‐dichlorophenoxyacetic acid (2,4‐D) at pH 6.9 under simulated sunlight irradiation (300 W m−2) and H2O2 concentrations of 10 mg L−1. The 2,4‐D removal was strongly enhanced by the presence of fluoride. F− could modify the surface of iron (hydr)oxide, leading to the formation of surface Fe–F bonds benefiting the formation of free •OH, producing upward band bending, reducing the electron‐hole recombination, and enhancing the electron transfer to H2O2. On the other hand, bicarbonate may react with •OH generating CO3−• species that could participate in pollutant oxidation, while solar light‐induced H2O2 photolysis also played an important role in removing 2,4‐D. These findings suggest that tuning of iron (hydr)oxides by fluoride could take place in real groundwater, generating photocatalysts with a high activity that could participate, by adding H2O2, in the enhancement of sunlight photoinduced natural abiotic processes for pollutant abatement. [ABSTRACT FROM AUTHOR]

Groundwater is the only source of clean water for human use in much of the world, but contaminants from the home, business, and agriculture-such as fertilizers and pesticides-can quickly contaminate it. The main objective of the current work was to investigate the photocatalytic removal of the herbicide 2,4-Dichlorophenoxyacetic acid (2,4-D) from an aqueous medium utilizing environmentally friendly zinc oxide nanoparticles. One of the main areas of research has been the possible use of zinc oxide (ZnO) nanoparticles in antifungal, antibacterial, and optical applications. Due to their unique qualities, the well-known nanoparticles utilized in nanotechnology and nanoscience have a wide range of practical applications in the chemical, pharmaceutical, medical, and rural sectors. These particles are used to degrade contaminants during synthetic production. Due to the availability of dangerous synthetic compounds and the outrageous climatic openness in these nanoparticles' physical and substance growth, eco-friendly approaches to utilizing plants have been established. The study includes a brief history of the production of zinc oxide nanoparticles and their application in the pollutant 2,4 D degrading process. This study highlights the use of neem extract in the manufacture of zinc oxide nanoparticles and their application in the removal of contaminants. [ABSTRACT FROM AUTHOR]

This article presents an environmentally friendly method of exploiting and recycling waste materials by synthesizing nanoparticles (NPs) from natural waste resources. Calcium oxide NPs have been synthesized from chicken eggshells through the sol-gel method. Sol-gel is a simple, cheap, low-temperature and low-pressure method for synthesizing metal oxide nanoparticles, which has many advantages over other mechanisms. The synthesized CaO nanoparticles were characterized by EDX, FTIR, XRD, SEM, HRTEM, BET, and UV-Visible spectroscopy. The as-synthesized CaO nanoparticles exhibit intrinsic peroxidase mimic activity (POD-like). A newly developed method was described for quantitatively determining 2,4-D herbicide residues based on their high POD-like activities and cascading catalytic reactions. The proposed method shows the limit of detection of 0.54 µg/mL, limit of quantification of 1.63 µg/mL, and the recovery was from 98.333 to 99.633%. The presented approach was successfully applied for estimation of 2,4-D in wastewater and soil samples and the results were compared with the results obtained from UV-Visible official method. [ABSTRACT FROM AUTHOR]

A bacterial strain 22S belonging to the genus Serratia was isolated from soil samples contaminated with chemical production wastes. The strain was found to be nonpathogenic based on the study of its virulence, toxicity, infectivity, and invasiveness. In batch culture, Serratia sp. 22S was able to separately utilize chlorophenoxyacetic acids (100 mg/L) as the sole source of carbon and energy. The catabolism pathway for chlorophenoxyacetic acids was suggested through complete reductive dechlorination of the substrate followed by meta-cleavage of the aromatic ring of catechol based on the compounds found in the culture medium (2,4-dichloro-6-methylphenoxyacetic, phenoxyacetic, and 2-hydroxy-2-hexenedionic acids). Intact cells experiments confirmed this assumption. In model systems, good adaptability and survival of the 22S strain in the soil was revealed, and the content of chlorophenoxyacetic acids up to a certain concentrations had a positive effect on the growth of the strain, most likely due to its selective effect. [ABSTRACT FROM AUTHOR]

Currently, there are no known human biomonitoring studies that concurrently examine biomarkers of dicamba and 2,4-D. We sought to compare biomarkers of exposure to herbicides in pregnant women residing in the US Midwest before and after the adoption of dicamba-tolerant soybean technology using urine specimens obtained in 2010–2012 from the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be (N = 61) and in 2020–2022 from the Heartland Study (N = 91). Specific gravity-standardized concentration levels for each analyte were compared between the cohorts, assuming data are lognormal and specifying values below the LOD as left-censored. The proportion of pregnant individuals with dicamba detected above the LOD significantly increased from 28% (95% CI: 16%, 40%) in 2010–2012 to 70% (95% CI: 60%, 79%) in 2020–2022, and dicamba concentrations also significantly increased from 0.066 μg/L (95% CI: 0.042, 0.104) to 0.271 μg/L (95% CI: 0.205, 0.358). All pregnant individuals from both cohorts had 2,4-D detected. Though 2,4-D concentration levels increased, the difference was not significant (p-value = 0.226). Reliance on herbicides has drastically increased in the last ten years in the United States, and the results obtained in this study highlight the need to track exposure and impacts on adverse maternal and neonatal outcomes. [ABSTRACT FROM AUTHOR]

Currently, there are no known human biomonitoring studies that concurrently examine biomarkers of dicamba and 2,4-D. We sought to compare biomarkers of exposure to herbicides in pregnant women residing in the US Midwest before and after the adoption of dicamba-tolerant soybean technology using urine specimens obtained in 2010–2012 from the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be (N = 61) and in 2020–2022 from the Heartland Study (N = 91). Specific gravity-standardized concentration levels for each analyte were compared between the cohorts, assuming data are lognormal and specifying values below the LOD as left-censored. The proportion of pregnant individuals with dicamba detected above the LOD significantly increased from 28% (95% CI: 16%, 40%) in 2010–2012 to 70% (95% CI: 60%, 79%) in 2020–2022, and dicamba concentrations also significantly increased from 0.066 μg/L (95% CI: 0.042, 0.104) to 0.271 μg/L (95% CI: 0.205, 0.358). All pregnant individuals from both cohorts had 2,4-D detected. Though 2,4-D concentration levels increased, the difference was not significant (p-value = 0.226). Reliance on herbicides has drastically increased in the last ten years in the United States, and the results obtained in this study highlight the need to track exposure and impacts on adverse maternal and neonatal outcomes.

Anaerobically digested sludge-derived biochar was produced through pyrolysis at 700 °C, called BC700. BC700 was characterized using a scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier-transform infrared spectroscopy (FTIR), and the Brunauer–Emmett–Teller (BET) method. The factors influencing the adsorption process and the mechanism involved in adsorbing tricyclazole and 2,4-D in single and binary systems were revealed. The theoretical maximum adsorption capacities of BC700 for tricyclazole and 2,4-D in a single system were 11.86 mg/g and 7.89 mg/g, respectively. In the binary system, the theoretical saturated adsorptive capacities of tricyclazole and 2,4-D were 5.27 mg/g and 3.20 mg/g, respectively. The adsorption of tricyclazole and 2,4-D by BC700, whether in single or binary systems, matched closely with the Freundlich isotherm and the pseudo-second-order model. This study indicates that anaerobically digested sludge-derived biochar is potentially valuable for removing pesticide contamination in surface water.

The present study presents the results obtained from evaluating the photocatalytic behavior of a series of sulfated CeO2 materials in the photocatalytic degradation of the herbicide 2,4-dichlorophenoxyacetic acid. The CeO2 photocatalytic support was prepared using the precipitation synthesis method. Subsequently, the support was wetly impregnated with different contents of sulfate ions (0.5, 1.0, and 2.0 wt.%). The materials were characterized using X-ray diffraction, nitrogen physisorption, infrared spectroscopy, diffuse reflectance UV–Vis spectrophotometry, and thermal analysis. The characterization results showed that the sulfation of the material promoted an increase in the surface area and a decrease in the average size of the crystallites. Likewise, it was possible to demonstrate the surface sulfation of the support through bidentate coordination of the sulfate groups to the semiconductor metal. Concerning photoactivity, the convenience of the surface modification of CeO2 was confirmed because the sulfate groups acted as capturers of the electrons generated during the photocatalytic process, reducing the frequency of recombination of the charge carriers and allowing the availability of the gaps to favor the degradation reaction of the contaminant. Finally, it was evident that a percentage of 1.0 wt.% of the sulfate anion is the optimal content to improve the photocatalytic properties of CeO2.

In this work, a comparison was made between the synthesis of niobium-based materials (Nb2O5), both in terms of material characterization and catalytic performance. The methods used were chemical mixtures: modified sol-gel and Pechini. The materials were calcined at different temperatures (753, 873 and 993K) and characterized by the following techniques: photoacousticspectroscopy (PAS), zero charge point (pHPZC), scanning electron microscopy (SEM/EDS), thermogravimetric analysis (TGA/DTG) and X-ray diffraction (XRD). The photocatalytic process was carried out to evaluate the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) under UV radiation (250 W mercury vapor lamp) and different experimental conditions. In addition, to better understand the influence of parameters such as pH, catalyst concentration (0.2, 0.5 and 0.8 g L−1) and calcination temperature, a Design of Experiments (DoE) was used. The results indicated that despite having similar structures and phases in the XRD analysis, the morphology presents two distinct surfaces, due to the preparation method. Differences in the synthesis method affected the catalytic activity in the parameters studied. Although the zero charge point values are close (6.18-6.36), we observed differences in the band gap depending on the calcination temperature. In the optimal condition studied, the catalyst prepared by the sol-gel method obtained the best results. [ABSTRACT FROM AUTHOR]

Nanomaterials are desirable for sensing applications. Therefore, MnO2 nanosheets and nitrogen-doped carbon dots (NCDs) were used to construct a ratiometric biosensor for quantification of 2,4-dichlorophenoxyacetic acid. The MnO2 nanosheets drove the oxidation of colorless o-phenylenediamine to OPDox, which exhibits fluorescence emission peaks at 556 nm. The fluorescence of OPDox was efficiently quenched and the NCDs were recovered as the ascorbic acid produced by the hydrolyzed alkaline phosphatase (ALP) substrate increased. Owing to the selective inhibition of ALP activity by 2,4-D and the inner filter effect, the fluorescence intensity of the NCDs at 430 nm was suppressed, whereas that at 556 nm was maintained. The fluorescence intensity ratio was used for quantitative detection. The linear equation was F = 0.138 + 3.863·C 2,4-D (correlation coefficient R2 = 0.9904), whereas the limits of detection (LOD) and quantification (LOQ) were 0.013 and 0.040 μg/mL. The method was successfully employed for the determination of 2,4-D in different vegetables with recoveries of 79%~105%. The fluorescent color change in the 2,4-D sensing system can also be captured by a smartphone to achieve colorimetric detection by homemade portable test kit. [ABSTRACT FROM AUTHOR]

This study analyzes the adsorption of two model pesticides, namely, 2,4-dichlorophenoxyacetic acid (2,4-D) and carbofuran on activated carbons obtained by chemical activation with phosphoric acid of peach stones. The effect of the synthesis conditions on the surface area development was analyzed. The highest surface area was obtained with an impregnation time of 5 h, an impregnation ratio equal to 3.5, an activation temperature of 400 °C, and 4.5 h of activation time. Under these conditions, the maximum specific surface area was equal to 1182 m2·g−1 which confirms the high porosity of the activated carbon, predominantly in the form of micropores. The surface chemistry of this activated carbon was also characterized using pH at point of zero charge, scanning electron microscopy, and Fourier transform infrared spectroscopy. Both kinetics and equilibrium adsorption tests were performed. Adsorption kinetics confirmed that 2,4-D adsorption follows a pseudo first-order adsorption kinetic model, while carbofuran adsorption is better described by a pseudo second-order one. Regarding the equilibrium adsorption, a higher adsorption capacity is obtained for 2,4-D than carbofuran (c.a. 500 and 250 mg·g−1, respectively). The analysis of the thermodynamics and characterization after use suggest a predominantly physisorption nature of the process. [ABSTRACT FROM AUTHOR]

This research investigates the potential of Balanites aegyptiaca (desert date) seed shells, an abundant renewable bio-waste product, as a precursor for producing low-cost activated carbon for the removal of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) from aqueous solution via batch technique adsorption. The chemical activation process was carried out using ZnCl2 as an activating agent at 700°C and 1:2 impregnation ratio. The activated carbon was characterized by “Boehm” titration, measurements of pH of the point zero charge, scanning electron microscopy, Fourier-transform infrared spectroscopy and specific surface areas (SMB) by methylene blue adsorption. The effects of initial herbicide concentration, contact time, solution pH, and solution temperature on the sorption capacity were investigated. Equilibrium data were fitted to the Langmuir, Freundlich, Temkin, Redlich– Peterson, Sips, and Toth models. The highest correlation coefficient (R2) values were obtained from Temkin model, with values of 0.997, 0.999, and 0.996 at 298.15, 308.15, and 318.15 K, respectively. The enthalpy change (ΔH°), entropy change (ΔS°) and free energy change (ΔG°) were also evaluated. The negative value of ΔG° shows that the adsorption process is spontaneous, and the positive value of ΔH° shows the endothermic nature of the process. The experimental data were tested through the pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. The pseudo- second-order kinetic model was the most fitting to the kinetics data (R2 > 0.981). Results showed that Balanites aegyptiaca seed shell activated carbon is very efficient for the removal of 2,4-D from aqueous solutions. [ABSTRACT FROM AUTHOR]

The emerging contaminant 2,4-dichlorophenoxyacetic acid (2,4-D) has been shown to have harmful effects on the environment and human health. These contaminants present a critical challenge in water remediation. Herein, a magnetic composite composed of silica-coated magnesium ferrite nanoparticles and glutaraldehyde-cross-linked polyethylenimine polymer (i.e., MgFe2O4@SiO2/GA-PEI composite) was synthesized to use as an effective adsorbent for the removal of 2,4-D. The successful preparation of the MgFe2O4@SiO2/GA-PEI composite using the optimal synthesis condition was confirmed through XRD, TGA-DTG, FTIR, zeta potential analysis, solid-state 13C NMR, TEM, SEM, EDS, VSM, and organic functional group tests. The adsorption behavior of 2,4-D by this composite was systematically investigated. The results showed that the MgFe2O4@SiO2/GA-PEI composite exhibited not only pH-dependent adsorption behavior but also an ultrahigh adsorption capacity (∼1631 mg g–1) for 2,4-D. The efficient adsorption of 2,4-D is due to the large numbers of functional groups (i.e., hydroxy and amines) in the obtained composite. Furthermore, the electrostatic interaction between the composite and 2,4-D molecules significantly influenced the adsorption behavior. The reusability test indicated that the MgFe2O4@SiO2/GA-PEI composite revealed the effective adsorption of 2,4-D after five adsorption–desorption cycles. This newly designed heterogeneous magnetic hybrid composite provides a unique foundation to perform ultrahigh removal capacity, easy separation, and reusability for harmful pesticide 2,4-D in water remediation. [ABSTRACT FROM AUTHOR]

The adsorption activity of a carbon material based on lignin modified with iron salts and carbonized under the influence of microwave radiation in relation to 2,4-dichlorophenoxyacetic acid (2,4-D) from an aqueous medium was studied. The kinetic parameters of the adsorption process were determined. Based on the results obtained, the possibility of using the test material as an adsorbent of biologically active organic compounds was shown. [ABSTRACT FROM AUTHOR]

Carbonaceous materials have been widely applied as adsorbents, but there are some factors that affect their efficiency. In this context, advances in nanotechnology provide new and more efficient methodologies for water treatment. This study evaluated the efficiency of a novel carbon-based adsorbent developed from Brazilian polyacrylonitrile textile fiber and functionalized with iron oxide magnetic nanoparticles for the removal of 2,4-dichlorophenoxyacetic acid (2,4-D) from the aqueous medium. The synthesized adsorbent (ACF-Fe3O4) was characterized by FTIR, XRD, VSM, Zeta potential, SEM, EDX, and TEM. The characterization techniques showed that the adsorbent has peaks characteristic of its precursors and superparamagnetic characteristics, confirming the efficiency of the synthesis method. The adsorption tests evaluated the influence of adsorbent dosage, pH of the contaminant solution, contact time and temperature on the removal of 2,4-D. The experimental data were better adjusted by the pseudo-second order kinetic model and by the Langmuir isothermal model. The thermodynamic parameters revealed that the process is exothermic, spontaneous and thermodynamically favorable. Under the best experimental conditions, the maximum adsorption capacity obtained was 51.10 mg g−1 with an adsorbent concentration of 0.33 g L−1, natural pH of the solution, temperature of 288 K at the equilibrium time of six hours. Adsorbent reusage was studied in four desorption cycles. The adsorption mechanism can be explained through π-π bonds, hydrogen bonds and electrostatic interactions. The prepared material presented high-efficiency adsorption capacity of 2,4-D compared to other carbonaceous materials present in the literature, demonstrating its viability for the removal of this contaminant from the aqueous medium. [ABSTRACT FROM AUTHOR]

【Objective】By comparing the differences in cell wall components among litchi varieties with different susceptibility to fruit cracking, the study aims to investigate the effects of exogenous application of auxin analogue 2,4-D on the cell wall composition of pericarp and fruit cracking, and to further explore the relationship between the cell wall synthesis metabolism and fruit cracking incidence.【Methods】The changes in carbohydrate contents of two easily cracked litchi varieties ('Guiwei' and 'Nuomici') and two not easily-cracked litchi varieties ('Huaizhi' and 'Lingfengnuo') after 75 days of flowering were compared, and the tissue structure and lignin distribution of the pericarps at the 60-85 d after flowering were observed. Fruit clusters of 'Nuomici' in two orchards were dipped into auxin analog 2,4-D, and the soluble sugar contents in the pericarps were determined by GC-MS. The starch and structural carbohydrate contents of the samples were detected by using a spectrophotometer. Transmission electron microscopy and lignin staining were used to observe the tissue structure of litchi pericarp.【Result】The contents of hexose including fructose, glucose and galactose in the pericarp of cracking susceptible variety 'Nuomici' were significantly lower than those of low-cracking varieties 'Huaizhi' and 'Lingfengnuo'. A complicate relationship between pectin contents and fruit cracking susceptibility was found. In the pericarp of 'Nuomici', the pectin content was only around 1.7 mg/g. And the fruit was bigger and susceptible to cracking. While in the cracking susceptible smaller fruit variety 'Guiwei', the pericarp contained high pectin (4.0 mg/g). 2,4-D treatment only temporarily increased the fruit setting rate of litchi in the early stage, but it had no significant impact on the final fruit setting rate. 2,4-D treatment could lead to an increase in the number of layers of pericarp cells and the blurring of the contour of inner pericarp cells; Compared with the control, the treatment with 40 mg/L 2,4-D resulted in an increase in pectin content, thickening of cell walls, and an increase in fruit cracking rate.【Conclusion】There are significant differences in the contents of carbohydrates in the pericarps of litchi varieties with different susceptibility to fruit cracking. Pectin may play a dual role in litchi fruit cracking. The development of pericarp requires dynamic changes in pectin synthesis and degradation. Pectin might play dual role in the cracking of litchi fruit. High pectin in the pericarp results in low expansion, smaller fruit size and higher cracking rate; while low pectin results in higher pericarp expansion, larger fruit size and higher cracking rate. 2,4-D treatment show no significant effect on the final fruit setting rate but will increase the risk of fruit cracking.

Abstract Herbicide residuals have posed severe threat to food safety and public health; thus, the development of smart, portable, efficient, and accurate on‐site detection system is in urgent demand. Here, a multi‐emitting fluorescent system‐assisted lab‐in‐a‐syringe (LIS) device was developed for the on‐site and background‐free determination of 2,4‐dichlorophenoxyacetic acid (2,4‐D). 2,4‐D‐responsive cascade reactions were constructed: 2,4‐D could specifically suppress alkaline phosphatase (ALP) activity and restrain the generation of ascorbic acid (AA), MnO2 nanosheets would oxidize AA into dehydroascorbic acid that subsequently reacts with o‐phenylenediamine (OPD) to generate blue‐emission product (λem, 435 nm), whereas remained MnO2 nanosheets and OPD further produced yellow‐emission product (λem, 570 nm). Red‐emission carbon dots (RCDs, λem, 680 nm), synthesized via the solvothermal treatment of cilantro, were introduced to construct a multi‐emitting fluorescent system. Then, four paper pads, respectively, dropped with ALP, sodium l‐ascorbyl‐2‐phosphate, MnO2 nanosheets + RCDs, and OPD were held into reusable plastic filters and assembled paper‐based LIS device to trigger cascade reactions (total analysis time, 65 min) and eliminate background interference. As a result, with the support of color recognizer application in smartphone, fluorescent color on detection pads from blue–purple to red to yellow was achieved for the sensitive and visual detection of 2,4‐D with LOD of 5.0 μg L−1, recoveries of 94.6%–106.8%, and relative standard deviations of 2.3%–6.8%. Obviously, this strategy provides a robust, visual, and background‐free platform for 2,4‐D detection, which expands application prospects in the field of herbicide analysis.

The development of highly efficient and stable visible-light-driven photocatalysts for the removal of herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) from water is still a challenge. In this work, Bi2MoO6 (BMO) materials with different morphology were successfully prepared via a simple hydrothermal method by altering the solvent. The morphology of the BMO material is mainly influenced by the solvent used in the synthesis (H2O, ethanol, and ethylene glycol or their mixtures) and to a lesser extent by subsequent thermal annealing. BMO with aggregated spheres and nanoplate-like structures hydrothermally synthesized in ethylene glycol (EG) and subsequently calcined at 400 °C (BMO-400 (EG)) showed the highest adsorption capacity and photocatalytic activity compared to other synthesized morphologies. Complete degradation of 2,4-D on BMO upon irradiation with a blue light-emitting diode (LED, λmax = 467 nm) was reached within 150 min, resulting in 2,4-dichlorophenol (2,4-DCP) as the main degradation product. Holes (h+) and superoxide radicals (⋅O2−) are assumed to be the reactive species observed for the rapid conversion of 2,4-D to 2,4-DCP. The addition of H2O2 to the reaction mixture not only accelerates the degradation of 2,4-DCP but also significantly reduces the total organic carbon (TOC) content, indicating that hydroxyl radicals are crucial for the rapid mineralization of 2,4-D. Under optimal conditions, the TOC value was reduced by 84.5% within 180 min using BMO-400 (EG) and H2O2. The improved degradation performance of BMO-400 (EG) can be attributed to its particular morphology leading to lower charge transfer resistance, higher electron–hole separation, and larger specific surface area.

We face significant environmental pollution problems due to various industries, such as the aluminum industry, which generates large amounts of red mud (RM) waste, or agriculture, in which case the use of pesticides creates huge water pollution problems. In this context, the present study offers a better perspective to originally solve both environmental issues. Thus, the main target of the study referred to using RM waste as a filler for preparing composite copolymer beads. Thereafter, this can achieve significant removal of water pollutants due to their adsorption/oxidation characteristics. As evidenced by the changes in chemical structure and composition, thermal stability, morphology, and porosity, RM was homogenously incorporated in poly(acrylonitrile-co-acrylic acid) beads prepared by wet phase inversion. The final assessment for the removal of pesticides by adsorption and oxidation processes was proven successful. In this regard, 2,4-dichlorophenoxyacetic acid was chosen as a model pollutant, for which an adsorption capacity of 16.08 mg/g composite beads was achieved.

This work demonstrates recent advancements in the phytosynthetic and environmentally friendly method of preparing ZnFe2O4 and ZnFe2O4@Ag hybrid nanocomposites using Pedalium murex L leaf extract as a stabilizing and reducing agent. The synthesized nanocomposite was characterized with UV–vis, FTIR, TGA/DSC, XRD, FE-SEM, and EDX to investigate the electronic as well as morphological properties. Moreover, the photocatalytic behaviour of ZnFe2O4 and ZnFe2O4@Ag hybrid nanocomposites was evaluated with a breakdown of 2,4-dichlorophenoxyacetic acid (2,4-DPA) by exposing to UV–Vis light. The results obtained suggest that ZnFe2O4@Ag hybrid nanocomposite exhibited photocatalytic activity for the degradation of 2,4-DPA by approximately 94% in 60 min compared to ZnFe2O4. The hybrid nanostructure of ZnFe2O4@Ag significantly promoted charge transfer and prevented electron and hole recombination resulting in the enhancement of photocatalytic activity. Furthermore, ZnFe2O4@Ag nanocomposite showed the fair recyclable capacity for up to five catalytic cycles with an acceptable degradation percentage of 2,4-DPA. The findings of this study identify efficient charge transfer factor as a major contributor to the catalytic activity, with promising possibilities for the design of environmental remediation nanocomposite for harmful contaminants.

This study was carried out for nine months to find bacterial strain capable of mineralizing 2,4-dichlorophenoxyacetic acid herbicide. A popular pre-/post emergent systemic herbicide known as 2, 4-dichlorophenoxyacetic Acid (2,4-D) is used to combat broad-leaved weeds and other plants on rangelands that are specifically intended to boost agricultural productivity and reduce losses the result of crop pests on agricultural products. This study's objective is to isolate, screen, and identify 2, 4-dichlorophenoxyacetic Acid degrading microorganisms from rice-growing soil in Kura local government area, Kano State. Experiments with incubation in mineral broth allowed for the isolation of 2, 4-dichlorophenoxyacetic Acid degrading bacteria. 2,4-dichlorophenoxyacetic Acid herbicide is added to salt medium. A native bacterial strain that can use 2, 4-dichlorophenoxyacetic Acid as its only source of carbon and energy was found in the soil of a rice field with a lengthy history of herbicide use. All the experiments were carried out in triplicates. Additionally, employed for data display were graphs and tables. An indigenous bacterial strain that is capable of 2,4-dichlorophenoxyacetic Acid supplementation in minimal salt medium were isolated from using 2,4-dichlorophenoxyacetic acid as the main alternative for energy and carbon from Rice cultivated lands. The strain named B3-BUK-BCH was recognized as Cupriavidus campinensis based on the analysis of sequence of 16S ribosomal RNA, morphological, and chemical features. The mineralization features of isolated B3-BUK-BCH was quantified using one factor at a time approach. The optimal conditions for 2,4-dichlorophenoxyacetic Acid degradation were as follows: pH 7, temperature 40 °C, 200 gL−1inoculum size, and 0.72 gL−1 of 2,4-D concentration. High-performance liquid chromatography (HPLC) was used to test the 2,4-D's propensity for degradation. Under ideal circumstances, up to 94.69% of the 2,4-D was degraded after 6 days of incubation, this isolate had never been reported as able to degrade 2,4-D based on the available literature in the study area. The isolated strain represents a great potential for bioremediation.

An experiment was conducted to evaluate the impacts of exogenous application of synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) on lentil (Lens culinaris M.) growth, yield, and nutritional parameters in the Department of Crop Botany, Bangladesh Agricultural University, Mymensingh. Six treatments of 2,4-D (T0 = 0; T1 = 0.3; T2 = 0.5; T3 = 0.8; T4 = 1; and T5 = 1.2 ppm 2,4-D) with three replications were used in this study. Data on growth, yield, and nutritional parameters were collected and analyzed. The response of exogenous application of 2,4-D was significant in improving the performance of all the growth and yield contributing parameters as compared to untreated control plants. Exogenous application of 1 ppm 2,4-D was found to be effective for increasing plant height, branch number, root length, root-shoot fresh, and dry weight, nodule number, flower number, pod number, pod length, number of grains plant-1, 100-grain weight, and yield. Exogenous 2,4-D treatment significantly reduced the maturity time of lentil grain. The lowest date of maturity was found at 0.8, 1.0, and 1.2 ppm 2,4-D treatments. In this study, results showed a significant increase of different macro- (N, P, K) and micro- (Fe, Mn, Zn) nutrient content, uptake, and protein content in lentil grains with 1 ppm 2,4-D. It has been also revealed that the minimum requirement of 2,4-D to produce 80% lentil yield was 0.83 ppm. As a result, it was determined that the exogenous application of 2,4-D treatments is promising for enhancing the growth and productivity of lentil. [ABSTRACT FROM AUTHOR]

Background: Parkinson's disease (PD) affects 1–2% of the population over the age of 60 and the majority of PD cases are sporadic, without any family history of the disease. Neuroinflammation driven by microglia has been shown to promote the progression of midbrain dopaminergic (mDA) neuron loss through the release of neurotoxic factors. Interestingly, the risk of developing PD is significantly higher in distinct occupations, such as farming and agriculture, and is linked to the use of pesticides and herbicides. Methods: The neurotoxic features of 2,4-Dichlorophenoxyacetic acid (2,4D) at concentrations of 10 µM and 1 mM were analyzed in two distinct E14 midbrain neuron culture systems and in primary microglia. Results: The application of 1 mM 2,4D resulted in mDA neuron loss in neuron-enriched cultures. Notably, 2,4D-induced neurotoxicity significantly increased in the presence of microglia in neuron-glia cultures, suggesting that microglia-mediated neurotoxicity could be one mechanism for progressive neuron loss in this in vitro setup. However, 2,4D alone was unable to trigger microglia reactivity. Conclusions: Taken together, we demonstrate that 2,4D is neurotoxic for mDA neurons and that the presence of glia cells enhances 2,4D-induced neuron death. These data support the role of 2,4D as a risk factor for the development and progression of PD and further suggest the involvement of microglia during 2,4D-induced mDA neuron loss. [ABSTRACT FROM AUTHOR]

Background: Resistance to 2,4‐Dichlorophenoxyacetic acid (2,4‐D) has been reported in several weed species since the 1950s; however, a biotype of Conyza sumatrensis showing a novel physiology of the rapid response minutes after herbicide application was reported in 2017. The objective of this research was to investigate the mechanisms of resistance and identify transcripts associated with the rapid physiological response of C. sumatrensis to 2,4‐D herbicide. Results: Differences were found in 2,4‐D absorption between the resistant and susceptible biotypes. Herbicide translocation was reduced in the resistant biotype compared to the susceptible. In resistant plants 98.8% of [14C] 2,4‐D was found in the treated leaf, whereas ≈13% translocated to other plant parts in the susceptible biotype at 96 h after treatment. Resistant plants did not metabolize [14C] 2,4‐D and had only intact [14C] 2,4‐D at 96 h after application, whereas susceptible plants metabolized [14C] 2,4‐D into four detected metabolites, consistent with reversible conjugation metabolites found in other 2,4‐D sensitive plant species. Pre‐treatment with the cytochrome P450 inhibitor malathion did not enhance 2,4‐D sensitivity in either biotype. Following treatment with 2,4‐D, resistant plants showed increased expression of transcripts within plant defense response and hypersensitivity pathways, whereas both sensitive and resistant plants showed increased expression of auxin‐response transcripts. Conclusion: Our results demonstrate that reduced 2,4‐D translocation contributes to resistance in the C. sumatrensis biotype. The reduction in 2,4‐D transport is likely to be a consequence of the rapid physiological response to 2,4‐D in resistant C. sumatrensis. Resistant plants had increased expression of auxin‐responsive transcripts, indicating that a target‐site mechanism is unlikely. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

[Objective]By comparing the differences in cell wall components among litchi varieties with different susceptibility to fruit cracking, the study aims to investigate the effects of exogenous application of auxin analogue 2,4-D on the cell wall composition of pericarp and fruit cracking, and to further explore the relationship between the cell wall synthesis metabolism and fruit cracking incidence.[Methods]The changes in carbohydrate contents of two easily cracked litchi varieties (‘Guiwei’ and ‘Nuomici’) and two not easily-cracked litchi varieties (‘Huaizhi’ and ‘Lingfengnuo’) after 75 days of flowering were compared, and the tissue structure and lignin distribution of the pericarps at the 60-85 d after flowering were observed. Fruit clusters of ‘Nuomici’ in two orchards were dipped into auxin analog 2, 4-D, and the soluble sugar contents in the pericarps were determined by GC-MS. The starch and structural carbohydrate contents of the samples were detected by using a spectrophotometer. Transmission electron microscopy and lignin staining were used to observe the tissue structure of litchi pericarp.[Result]The contents of hexose including fructose, glucose and galactose in the pericarp of cracking susceptible variety ‘Nuomici’ were significantly lower than those of low-cracking varieties ‘Huaizhi’ and ‘Lingfengnuo’. A complicate relationship between pectin contents and fruit cracking susceptibility was found. In the pericarp of ‘Nuomici’, the pectin content was only around 1.7 mg/g. And the fruit was bigger and susceptible to cracking. While in the cracking susceptible smaller fruit variety ‘Guiwei’, the pericarp contained high pectin (4.0 mg/g). 2,4-D treatment only temporarily increased the fruit setting rate of litchi in the early stage, but it had no significant impact on the final fruit setting rate. 2,4-D treatment could lead to an increase in the number of layers of pericarp cells and the blurring of the contour of inner pericarp cells; Compared with the control, the treatment with 40 mg/L 2,4-D resulted in an increase in pectin content, thickening of cell walls, and an increase in fruit cracking rate.[Conclusion]There are significant differences in the contents of carbohydrates in the pericarps of litchi varieties with different susceptibility to fruit cracking. Pectin may play a dual role in litchi fruit cracking. The development of pericarp requires dynamic changes in pectin synthesis and degradation. Pectin might play dual role in the cracking of litchi fruit. High pectin in the pericarp results in low expansion, smaller fruit size and higher cracking rate; while low pectin results in higher pericarp expansion, larger fruit size and higher cracking rate. 2,4-D treatment show no significant effect on the final fruit setting rate but will increase the risk of fruit cracking. [ABSTRACT FROM AUTHOR]

A superior heterojunction of HC-ZnBi-LDO was synthesized in two steps, namely hydrothermal carbonization, followed by co-precipitation. The 2% HC-ZnBi-LDO heterojunction photocatalysts could degrade over 90.8% of 30 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) using 1.0 g/L of the catalyst after 135 min of visible light exposure at pH 4. The activity of 2% HC-ZnO-LDO was remarkably stable. Approximately 86.4–90.8% of 30 mg/L 2,4-D was degraded, and more than 79–86.4% of TOC was mineralized by 2% HC-ZnBi-LDO at pH 4 after 135 min of visible light exposure during four consecutive cycles. The rapid separation and migration of charge carriers at the interfaces between HC and ZnBi-LDO were achieved within 2% HC-ZnBi-LDO. Moreover, the electron acceptor characteristic of HC in 2% HC-ZnBi-LDO caused the recombination of charge carriers to decrease significantly, thus generating more reactive radicals, such as hydroxyl radicals (OH●) and superoxide radicals (O2●−). These results demonstrate that the novel 2% HC-ZnBi-LDO is a superior photocatalyst for the remediation of hazardous organic pollutants. [ABSTRACT FROM AUTHOR]

This study was aimed to screen a plant hormone that can increase the microalgae growth and lipid accumulation when cultured in municipal wastewater. The effects of four plant hormones on the biomass and lipid yield of the microalgae Chlorella pyrenoidosa cultured in sewage were studied. It was found that 2,4-dichlorophenoxyacetic acid (2,4-D) with 1.00 mg/L had the optimum effect. The microalgae biomass and lipid content with 2,4-D treatment were 0.86 and 0.46 g/L, which were enhanced by 89.7 and 76.5% compared with the control, respectively. In the outdoor scale-up test, the biomass and lipid in the treatment group were 0.75 and 0.38 g/L, respectively. The increase of total lipid was due to the increase of microalgae biomass because the lipid content in the microalgae cell did not change much. The fatty acids composition analysis for the microalgae lipid showed that the main components of the lipid were 16-corbon fatty acids and 18-corbon fatty acids, which were suitable for biodiesel production. Meanwhile, the nitrogen and phosphorus indexes of effluent decreased significantly, including 87.3% removal of total nitrogen, 94.1% removal of ammonia nitrogen, and 90.0% removal of total phosphorus. The results of relative membrane permeability showed that plant hormone 2,4-D changed the cell permeability of microalgae. The relative membrane permeability of treatment group was 69.5%, 56% higher than that in the control group, which promoted the propagation of microalgae. The results showed that the addition of plant hormone improved the microalgae growth, while degraded nitrogen and phosphorus pollutants in sewage, which provided ideas for the industrial production of microalgae biodiesel and municipal wastewater reuse. [ABSTRACT FROM AUTHOR]

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In order to investigate the salt stress induced chlorophyll biosynthesis-related genes in photoheterotrophic cultures, we performed RNA-Seq analysis on A. thaliana calli exposed to 100 mM NaCl on MS medium containing 0.5 mg/L 2,4-D 30 days. Four different conditions of samples were sequenced on Illumina HiSeq Platform in total and generated about 4.49 Gb per sample. The average genome and gene mapping rates were 93.52% and 90.78%, respectively. According to expression profile analysis, some DEGs demonstrated altered related to chlorophyll pigment metabolism. According to analysis, green callus color of photoheterotrophic calli were mainly connected with the induction of LHCB4.3 light harvesting complex photosystem II (Gene ID:818599), AT1G49975 photosystem I reaction center subunit N (Gene ID: 841421), PAM68 PAM68-like protein (DUF3464) (Gene ID: 2745715) and AT3G63540 thylakoid lumenal protein (Mog1/PsbP/DUF1795-like photosystem II reaction center PsbP family protein)(Gene ID: 7922413) genes. Furthermore, 8 DEGs were randomly selected to validate the transcriptome profiles via qPCR. These results will provide a foundation for further studies aimed at giving photosynthetic properties to in vitro plant cultures. [ABSTRACT FROM AUTHOR]

Background: Russia is one of the largest peanut importing countries. At the same time, in the south of the country, several zones meet the requirements for peanut cultivation. It is possible to increase the yield of the existing peanut varieties by using modern biotechnology methods, in particular agrobacterial transformation. It is known from the literature data that different peanut genotypes and explants from various sources react differently to in vitro regeneration. Successful regeneration depends on the correct protocol, including both the type of regeneration and the composition of media promoting growth and in vitro induction. Objectives: a technique for obtaining peanut regenerants in in vitro culture. Materials and methods: Eight peanut accessions from the VIR collection of different origin were used in the work. Embryonic explants were grown on Murashige-Skoog medium supplemented with the hormone 2,4-dichlorophenoxyacetic acid (2,4-D). Results and conclusions: As a result of assessing the regenerative ability of peanuts grown on Murashige-Skoog medium with the hormone 2,4-D at a concentration of 2 g/L, differences in the callus formation ability were revealed in different accessions. Those with catalog numbers k-793, k-2054 and k-2055 did not form organogenic calli, while accessions k-698 and k-1987 showed the highest percentage of callus formation from embryonic explants.

In this study, a green adsorbent (Fe3O4-UiO-66-NH2) with the ability of addressing the issues of separation and recovery of UiO-66-NH2 is obtained using a simple co-precipitation method under environmentally benign conditions. Various characterization techniques are utilized for evaluating the properties of the developed adsorbent. The capability of Fe3O4-UiO-66-NH2 towards 2,4-dichlorophenoxyacetic acid (2,4-D) and glyphosate (GP) from solution is explored. The results revealed that the magnetization process did not destroy the crystal structure of UiO-66-NH2, which ensured that Fe3O4-UiO-66-NH2 had good adsorption performance for 2,4-D and GP. The adsorption processes showed a wide pH application range, high salt tolerance, and regeneration performance as well as an excellent adsorption rate. Results from thermodynamic study showed that both processes were spontaneous and endothermic. The unit uptake ability of Fe3O4-UiO-66-NH2 for 2,4-D and GP reached up to 249 mg·g−1 and 183 mg·g−1 from Langmuir model at 303 K, respectively. When solid–liquid ratio was 2 g·L−1, Fe3O4-UiO-66-NH2 can reduce the content of 2,4-D or GP with the initial density of 100 mg·L−1 below the drinking water requirement limit. In addition, the reusability efficiency of Fe3O4-UiO-66-NH2 towards 2,4-D and GP was found to be 86% and 80% using 5 mmol·L−1 NaOH as eluent. Analysis of simulated water samples indicated that Fe3O4-UiO-66-NH2 could achieve the single or simultaneous removal of 2,4-D and GP from wastewater. Summarily, Fe3O4-UiO-66-NH2 as a green adsorbent can serve as an alternative for removing 2,4-D and GP from water body. [ABSTRACT FROM AUTHOR]

Creeping bentgrass (Agrostis stolonifera L.) is a turfgrass species that is widely used on golf courses throughout the United States. In field settings, plants are often subjected to more than one stress at a time, and studying stresses independently is likely insufficient. Stresses, such as heat stress and salt stress, can affect plant hormone levels and, in turn, plant hormone levels can affect how well the plant tolerates stress. The objectives of the experiments were to determine if the levels of heat stress and salt stress used would be detrimental to creeping bentgrass health, and if applying plant growth regulators could improve plant health during stress. During the first experiment, creeping bentgrass was transplanted to hydroponics systems in two different growth chambers. One chamber was set to have day and night temperatures of 35 °C and 30°C (heat stress), respectively, and the other had day and night temperatures of 25 °C and 20°C, respectively. Within each chamber, one block received a 50 mM NaCl treatment (salt stress) and the other did not (control). The stress treatments were applied for 14 days. Results of the first experiment indicated that the treatments were sufficient to negatively affect creeping bentgrass growth and health as indicated by fresh shoot and root weights, tillering, electrolyte leakage, and total chlorophyll content (TCC). There were significant interactions of temperature x salt level detected for shoot and root weights and electrolyte leakage. Plants that were exposed to both heat stress and salt stress were more negatively affected than plants exposed to either heat stress or salt stress alone for all metrics except for tillering. The presence of salt reduced tillering regardless of the temperature regimen. During the second experiment, plants were treated the same, but the plant growth regulator (PGR) treatments were also applied. The PGR treatments consisted of two different gibberellic acid (GA) synthesis inhibitor products, 2,4-dichlorophenoxyacetic acid, two different rates of aminoethoxyvinylglycine (AVG), an ethylene synthesis suppressor, and plants that were not treated with the PGR. In addition to the measurements of plant health and growth, dry shoot and root weights were measured. For the TCC, there was a two-way interaction between temperature x PGR treatment. For electrolyte leakage, there was a three-way interaction between temperature x salt level x PGR treatment. Combined heat stress and salt stress negatively affected all plants regardless of PGR treatment, but there were differences between PGR treatments. Plants treated with AVG exhibited improved health and growth compared with the other PGR treatments. These plants had the highest shoot and root masses. Plants treated with GA synthesis inhibitors had the lowest shoot and root masses as well as the lowest TCC when subjected to stress. [ABSTRACT FROM AUTHOR]

The purpose of this study was to develop a method for the extraction and determination of 2,4-dichlorophenoxyacetic acid (2,4-D) from the soil, sediment, and water, and to investigate its stability in water using high-performance liquid chromatography (HPLC). The recoveries of the spiked compound from water and soil samples was found to be in the range of 80 to 100%. The yield of 2,4-D during acidification of the corresponding amine was 93.84-99.98%. A calibration curve for the method showed good linearity (R² = 0.9996). The LOD was determined to be 0.45 μg/mL while the LOQ was 2 μg/mL. From the analysis of the samples, 2,4-D was not detected in sediment or soil samples from the Wafiko or Kontola sites (Ethiopia), respectively. The 2,4-D concentrations in soil samples from Bochessa, and water samples from Wafiko and Sher sites (Ethiopia) were high, ranging from 68.22 to 167.7 mg/L which exceeded the United States Environmental Protection Agency (US EPA) regulatory agency standards of 70 μg/L. A 45-day experiment on spiked water samples from Lake Koka (Ethiopia) demonstrated that the acidic form of 2,4-D is stable in water with 73.46 ± 2.00% recoveries. The developed method can be used to determine 2,4-D residues in soil, sediment, and water. [ABSTRACT FROM AUTHOR]

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