Tribenuron Methyl Research Articles

Wild mustard (Sinapis arvensis L.) resistance to tribenuron methyl in wheat fields of Diyarbakır province, Türkiye

Chemical weed control is unavoidable in the fields where weeds cause problems in wheat production. However, resistance problems in weeds arise a few years later especially using herbicides with the same mode of action continuously. Frequent and inappropriate use of herbicides leads to various environmental, health and economic issues, as well as labour losses. Recently, growers complained that tribenuron-methyl (acetolactate synthase - ALS), commonly used to control wild mustard (Sinapis arvensis L.-SINAR), which is causing problems in the wheat fields of Diyarbakır province, is ineffective. To determine the extent of the problem, wild mustard seeds were collected from 56 suspected wheat fields in 16 districts of Diyarbakır. As a result of applications carried out with the method under controlled conditions, resistance was suspected in the population of 28 fields. The results of the dose-response experiments indicated that no resistance (RI

Novel mutations in acetolactate synthase confer high levels of resistance to tribenuron-methyl in Fagopyrum tataricum

Tartary buckwheat (Fagopyrum tataricum) field weeds are rich in species, with many weeds causing reduced quality, yield, and crop failure. The selection of herbicide-resistant Tartary buckwheat varieties, while applying low-toxicity and efficient herbicides as a complementary weed control system, is one way to improve Tartary buckwheat yield and quality. Therefore, the development of herbicide-resistant varieties is important for the breeding of Tartary buckwheat. In this experiment, 50 mM ethyl methyl sulfonate solution was used to treat Tartary buckwheat seeds (M1) and then planted in the field. Harvested seeds (M2) were planted in the experiment field of Guizhou University, and when seedlings had 5–7 leaves, the seedlings were sprayed with 166 mg/L tribenuron-methyl (TBM). A total of 15 resistant plants were obtained, of which three were highly resistant. Using the homologous cloning method, an acetolactate synthase (ALS) gene encoding 547 amino acids was identified in Tartary buckwheat. A GTG (valine) to GGA (glycine) mutation (V409G) occurred at position 409 of the ALS gene in the high tribenuron-methyl resistant mutant sm113. The dm36 mutant harbored a double mutation, a deletion mutation at position 405, and a GTG (valine) to GGA (glycine) mutation (V411G) at position 411. The dm110 mutant underwent a double mutation: an ATG (methionine) to AGG (arginine) mutation (M333R) at position 333 and an insertion mutation at position 372. The synthesis of Chl a, Chl b, total Chl, and Car was significantly inhibited by TBM treatment. TBM was more efficient at suppressing the growth of wild-type plants than that of mutant plants. Antioxidant enzyme activities such as ascorbate peroxidase, peroxidase, and superoxide dismutase were significantly higher in resistant plants than in wild-type after spraying with TBM; malondialdehyde content was significantly lower than in wild-type plants after spraying with TBM. Plants with a single-site mutation in the ALS gene could survive, but their growth was affected by herbicide application. In contrast, plants with dual-site mutations in the ALS gene were not affected, indicating that plants with dual-site mutations in the ALS gene showed higher levels of resistance than plants with a single-site mutation in the ALS gene.

Новый гербицидоустойчивый сорт подсолнечника масличного типа Бузулук сур

Early maturing herbicide resistant sunflower variety of oil type Buzuluk sur (elite number 875) was developed as a result of the breeding and genetic program on development of sulfonylurea resistant plants at the V.S. Pustovoit All-Russian Research Institute of Oil Crops. This variety was developed using a complex of hybridization methods, backcrosses, and group repollination. A line VK1-sur was a donor of a resistance gen to tribenuron methyl (Sur), early maturing variety of oil type was a recipient. Subsequent individual selection with progeny estimation of the best by its morphological and economically valuable traits families and a control of herbicide resistance on the all stages of a breeding process allowed creating a population resistant to tribenuron methyl. The new variety is designed for cultivation in the production system Sumo and ExpressSun.

The effectiveness of sulfonylurea-based herbicides against dicotyledonous weed species on spring wheat crops in the Southern forest-steppe of the Trans-Urals

The effectiveness of chemical treatment differs significantly depending on the region and the types of weeds. In this regard, in the Kurgan region in 2018-2020, a comparative assessment of preparations based on sulfonylureas in spring wheat crops was carried out to identify the application features in the conditions of the Trans-Urals. The research was carried out on the experimental field of the Kurgan Research Institute of Agricultural Sciences -of the branch of the FSNSI UrFARC UrB RAS as part of the grain-fallow crop rotation. The purpose of the research was to determine the effectiveness of the use of sulfonylurea-based herbicides in spring wheat crops for the control of dicotyledonous perennial and young weed species. The main task was to determine the herbicide that most completely suppresses weed vegetation and has a positive effect on yield. According to the research results, a good effectiveness of weed control at the level of 74-76% was noted in preparations based on metsulfuronmethyl 10 g/ha, as well as in a mixture of metsulfuron-methyl and tribenuron methyl 12 g/ha. A 64-69% reduction in the mass of weeds was obtained using the tribenuron-methyl and florasulam 30 g/ha variant. The weakest control of weeds was detected in the variant with tribenuronmethyl 20 g/ha (biological efficiency 57%). The tested drugs provided yield increases of +19-24% to the control level.

Inheriting the resistance of sunflower to tribenuron methyl under insufficient humidification in the southern Steppe of Ukraine

Aim. This study aimed to investigate the inheritance of resistance to sulfonylurea herbicides in sunflower under conditions of insufficient humidification in the southern Steppe of Ukraine. Methods. Isolation, castration, hybridization, herbicide application (Granstar Pro 75 % w.g., containing tribenuron methyl as the active substance (a.s.)), evaluation of herbicide resistance, and statistical analysis of the acquired data. Results. The investigation into the inheritance of resistance to sulfonylurea herbicides involved the utilization of both resistant (SURES-1, OS 1099 V, OS 2017 V) and non-resistant (Od 1002 B, Od 1318 V, OS 1295 V) sunflower genotypes. Through crossing, four F1 hybrid combinations were generated, namely OS 2017 V × OS 1099 V, SURES-1 × Od 1002 B, SURES-1 × Od 1318 V, and Od 1318 V x OS 1295 V. Subsequent treatment of F1 plants with the herbicide Granstar Pro 75 % w.g. revealed that three combinations (OS 2017 V × OS 1099 V, SURES-1 × Od 1002 B, SURES-1 × Od 1318 V) exhibited complete resistance to the herbicide. In the second generation, following herbicide treatment, the hybrid combinations SURES-1 × Od 1002 B and SURES-1 × Od 1318 V displayed segregation into resistant and non-resistant plants. Conversely, the plants in the combination OS 2017 V × OS 1099 V maintained complete resistance to the herbicidal effects. Conclusions. The investigation, conducted in the challenging climatic conditions of the southern Steppe of Ukraine, demonstrated complete resistance to sulfonylurea herbicides in three hybrid combinations of both F1 and F2 generations. Notably, the combination OS 2017 V × OS 1099 V exhibited uniform resistance throughout the second generation, devoid of segregation. Moreover, the results of F2 segregation analysis in the SURES-1 × Od 1002 B and SURES-1 × Od 1318 V populations indicated that resistance to tribenuron methyl is primarily governed by the presence of a dominant gene allele. These findings offer valuable insights for the development of sunflower hybrids with enhanced herbicide resistance, particularly in regions with adverse climatic conditions.

Determination of Yield and Quality Characteristics of Tribenuron Methyl Group Sunflower Genotypes Newly Developed

The present study was conducted to determine the yield and quality characteristics of oil sunflower genotypes as candidates for registration under Konya and Karaman conditions, in 4 replications according to the “Random Blocks Trial Design”. The differences between the cultivars used in both locations of the study in terms of the number of days to bloom, the number of days to physiological maturity, the diameter of the tray, the thousand seed weight, seed moisture, seed yield, oil content, and oil yield were found to be statistically significant. The number of flowering days of the genotypes was found to be 64.5-60.8 days (H412; P63LLE113), the number of days to physiological maturity was 113.9-110.3 days (H412; P63LLE113), plant height 169.0-164.6 cm (M94S35; P63LE113), head diameter 20.9-17.3 cm (H412; P63LLE113), thousand-seed weight 60.3-47.4 g (H408; P64LE119), seed moisture 7.8-5.9 % (H408; P63LE113), seed yield 43.6-43.2 t ha-1 (H412; P64LE119), oil content 44.2-41.8 (H412; M94S35), and oil yield 19.2-17.0 t ha-1 (H412; P63LE113). The study showed that high yields could be achieved by using newly-developed hybrid sunflower genotypes in the conditions in the region. According to the averages of the location, it can be argued that the H412 hybrid that has high seed and oil yield can be successfully grown in regional conditions.

English

The study work was carried out in order to prevent vegetative growth of summer asphodel which makes the management of rangelands difficult and shows toxic effects on grazing. This research work was conducted between the years of 2014-2017 in the Canakkale Province, Turkiye. The experiment trials were established according to the randomized complete block design by using three replications. Experimental treatments were consisted of five herbicides and their two different doses. Herbicide applications were done in the autumn of 2014 and summer of 2015 when the weed started its newly sprouted vegetative growth. Chlorsulfuron (7.5g/da and 15g/da), glyphosate (300ml/da and 600ml/da), dicamba+triasulfurun (12.5g/da and 25g/da), metsulfuron methyl+lodosulfuron methyl (25g/da and 50g/da), and tribenuron methyl+thifensulfuron methyl (2g/da and 4g/da) herbicides were used by applying their recommended and double doses, respectively. Upper and sub soil developments of summer asphodel were investigated. Consequently, a decrease of 80-85% in upper soil development and 60-95% in sub soil development of summer asphodel was observed after applying five different herbicides. In conclusion, it is suggested that the herbicides with active ingredients of glyphosate, metsulfuron methyl+lodosulfuron methyl and tribenuron methyl+thifensulfuron methyl can be used in the management of summer asphodel weed.

Comparative proteomic and physiological analyses reveal tribenuron-methyl phytotoxicity and nontarget-site resistance mechanisms in Brassicanapus.

The application of herbicides is the most effective strategy for weed control and the development of herbicide-resistant crops will facilitate the weed management. The acetolactate synthase-inhibiting herbicide, tribenuron-methyl (TBM), is broadly used for weed control. However, its application in rapeseed field is restricted since rapeseed is sensitive to TBM. Herein, an integrated study of cytological, physiological and proteomic analysis of the TBM-resistant rapeseed mutant M342 and its wild-type (WT) plants was conducted. After TBM spraying, M342 showed improved tolerance to TBM, and proteins implicated in non-target-site resistance (NTSR) to herbicides had a significantly higher level in M342 as compared with the WT. Differentially accumulated proteins (DAPs) between these two genotypes were enriched in glutathione metabolism and oxidoreduction coenzyme metabolic process, which protected the mutant from oxidative stress triggered by TBM. Important DAPs related to stress or defence response were up-accumulated in M342regardless of the TBM treatment, which might serve as the constitutive part of NTSR to TBM. These results provide new clues for further exploration of the NTSR mechanism in plants and establish a theoretical basis for the development of herbicide-resistant crops.

Assessment of Tribenuron Methyl Soil Residual on Crops Germination Properties

Assessment of Tribenuron Methyl Soil Residual on Crops Germination Properties

An Asp376Glu substitution in ALS gene and enhanced metabolism confers high tribenuron-methyl resistance in Sinapis alba.

Acetolactate synthase (ALS) inhibiting herbicides (group 2) have been widely applied for the last 20 years to control Sinapis alba in cereal crops from southern Spain. In 2008, a tribenuron-methyl (TM) resistant (R) S. alba population was first reported in a cereal field in Malaga (southern Spain). In 2018, three suspected R S. alba populations (R1, R2 and R3) to TM were collected from three different fields in Granada (southern Spain, 100 km away from Malaga). The present work aims to confirm the putative resistance of these populations to TM and explore their resistance mechanisms. Dose-response assays showed that the R1, R2 and R3 populations ranging between 57.4, 44.4 and 57.1 times more resistance to TM than the susceptible population (S). A mutation in the ALS gene (Asp376Glu) was detected in the Rs S. alba populations. 14C-metabolism studies show that metabolites and TM were changing significantly faster in the R than in the S plants. Alternative chemical control trials showed that 2,4-D and MCPA (auxin mimics), glyphosate (enolpyruvyl shikimate phosphate synthase,EPSPS, inhibitor-group 9), metribuzin (PSII inhibitors/Serine 264 Binders, -group 5) and mesotrione (hydroxyphenyl pyruvate dioxygenase, HPPD, inhibitor-group 27) presented a high control of the four populations of S. alba tested, both S and R. Based on these results, it is the first case described where the Asp376Glu mutation and P450-mediated metabolism participates in resistance to TM in S. alba. Comparing these results with those found in the S. alba population in Malaga in 2008, where the resistance was TSR type (Pro197Ser), we can suggest that despite the geographical proximity (over 100 km), the resistance in these cases was due to different evolutionary events.

Smartphone-based colorimetric sensor array using gold nanoparticles for rapid distinguishment of multiple pesticides in real samples

A simple, sensitive method for pesticide distinguishment based on a colorimetric sensor array using diverse gold nanoparticles (AuNPs) at room temperature is presented in this study. Acetylcholinesterase (AChE) hydrolysis ability was influenced by different pesticides and produced different concentrations of thiocholine by hydrolyzing acetylthiocholine iodide (ATCh). Thiocholine could be easily linked to the AuNPs through an Au − S covalent bond, and AuNPs underwent aggregation, resulting in a visible color change due to alteration of surface plasmon resonance properties. Based on these results, we successfully distinguished eight pesticides (glyphosate, thiram, imidacloprid, tribenuron methyl, nicosulfuron, thifensulfuron methyl, dichlorprop, and fenoprop) utilizing five different AuNPs by colorimetric assay. The limit of detection (LOD) of this visual method for all pesticides was less than 1.5 × 10-7 M, which was more sensitive than the U.S. Environmental Protection Agency regulations specify (1.18 ∼ 3.91 × 10-6 M). This method was further improved by combining a portable smartphone device with a color picking application using (color name AR) and RGB (red, green, blue) values. The method was successfully applied to pesticide residue distinguishment in real samples by linear discriminant analysis (LDA).

A novel naturally Phe206Tyr mutation confers tolerance to ALS-inhibiting herbicides in Alopecurus myosuroides

Herbicide-resistant weeds pose a serious threat to world food production. The rapid and widespread development of target-site based resistance limits the application of herbicides. Alopecurus myosuroides Huds. (blackgrass) has spread rapidly in winter wheat regions in China, and the field recommended dose of ALS herbicides no longer controls blackgrass populations in recent years. A highly resistant population TW18(R) was collected in 2018 from Shandong Province. Dose-response assays showed that the TW18 was resistant to mesosulfuron-methyl, flucarbazone-sodium, and imazethapyr, with resistance index values of 5.96, 6.1, and 4.09, respectively. DNA sequencing of the TW18 population revealed a Phe206Tyr (F206Y) mutation in the ALS, which was not yet reported. Blackgrass ALS gene with the F206Y mutation (R gene) was expressed in Arabidopsis and rice. Transgenic studies have shown that both Arabidopsis and rice expressing this R gene have resistance to imazethapyr. However, it did not confer resistance to tribenuron methyl and florasulam in transgenic Arabidopsis. This study showed that the F206Y substitution caused herbicide resistance in blackgrass. To our knowledge, this is the first-reported F206Y mutation of a weed species in the natural environment. Transgenic plants showed this functional site could be utilized to generate imazethapyr-resistant rice to control herbicide-resistant weed damage.

Biodegradation and Subsequent Toxicity Reduction of Co-contaminants Tribenuron Methyl and Metsulfuron Methyl by a Bacterial Consortium B2R.

AllyMax is a widely used herbicide formulation in wheat-rice cropping areas of the world. The residues of its active ingredients, tribenuron methyl (TBM) and metsulfuron methyl (MET), persist in soil and water as co-contaminants, and cause serious threats to nontarget organisms. This study was performed to assess the potential of a bacterial consortium for the degradation and detoxification of TBM and MET individually and as co-contaminants. A bacterial consortium (B2R), comprising Bacillus cereus SU-1, Bacillus velezensis OS-2, and Rhodococcus rhodochrous AQ1, capable of degrading TBM and MET in liquid cultures was developed. Biodegradation of TBM and MET was optimized using the Taguchi design of experiment. Optimum degradation of both TBM and MET was obtained at pH 7 and 37 °C. Regarding media composition, optimum degradation of TBM and MET was obtained in minimal salt medium (MSM) supplemented with glucose, and MSM without glucose, respectively. The consortium simultaneously degraded TBM and MET (94.8 and 80.4%, respectively) in cultures containing the formulation AllyMax, where TBM and MET existed as co-contaminants at 2.5 mg/L each. Mass spectrometry analysis confirmed that during biodegradation, TBM and MET were metabolized into simpler compounds. Onion (Allium cepa) root inhibition and Comet assays revealed that the bacterial consortium B2R detoxified TBM and MET separately and as co-contaminants. The consortium B2R can potentially be used for the remediation of soil and water co-contaminated with TBM and MET.

A study of the properties and efficacy of microparticles based on P(3HB) and P(3HB/3HV) loaded with herbicides

AbstractThe wide use of pesticides in agriculture has caused uncontrolled distribution of these chemicals in the environment, calling for the development and investigation of new environmentally friendly formulations, which would reduce human impact on nature. In the present study, the metribuzin (MET), tribenuron‐methyl (TBM), and fenoxaprop‐P‐ethyl (FPE) herbicides were encapsulated in microparticles of degradable microbial polymers – polyhydroxyalkanoates (PHAs) – of two types – poly‐3‐hydroxybutyrate [P(3HB)] and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate [P(3HB/3HV)]. The use of P(3HB) resulted in higher yields of microparticles (63% to 79%) and larger sizes of the particles, whose average diameter was 0.60 ± 0.06–0.75 ± 0.11 μm, while the average diameter of copolymer particles varied between 0.43 ± 0.12 and 0.55 ± 0.05 μm. Encapsulation efficiency was rather determined by the type of herbicide and its solubility, varying from 24.7% to 48.2%. In vitro herbicide release from microparticles to water was affected by herbicide solubility and PHA chemical composition. The readily soluble MET showed the highest release rate, and over 30 days, 64% and 78% of the encapsulated amounts were released from P(3HB) and P(3HB/3HV) microparticles, respectively. High herbicidal activity of microparticles loaded with metribuzin and tribenuron‐methyl was demonstrated in the laboratory stands of the Elsholtzia ciliata weed plant.

Humic and Fulvic Acids as Specific Sorbents of Herbicides in Water

AbstractThe ability of humic and fulvic acids (isolated from lignite with a simple, quick, and inexpensive method) to bind the active ingredients of herbicides contaminating drinking water is evaluated. During this study drinking water samples are contaminated with formulated herbicides (imazamox or a mixture of thifensulfuron methyl and tribenuron methyl), while humic and fulvic acids are used as reducing agents. The maximum reducing ability presented by humic and fulvic acids is 72.72% for thifensulfuron methyl and tribenuron methyl and 37.52% for imazamox. Humic acids’ binding ability is superior to that of fulvic acids.

Teratological Effects of Tribenuron Methyl on Zebra Fish Embryo and Larva

Tribenuron metil tarımda çok yıllık dikotları kontrol etmek için kullanılan herbisittir. Sucul ekosistemlere yeraltı suyu yoluyla erişebilir ve sucul yaşamı etkileyebilir. Zebra balığı (Danio rerio Hamilton, 1822), kolay üreme kapasitesine ve şeffaf embriyolara sahip olan ve bu yüzden bilimsel çalışmalarda sıkça tercih edilen bir omurgalı modelidir. Bu çalışmada tribenuron metil zebra balıkları üzerinde 120 saatlik LC50 değerinin 1.850 mg L-1 olarak tespit edildi. Bu değerden yola çıkarak uygulanan 1.812 mg L-1, 0.906 mg L-1, 0.453 mg L-1, 0.226 mg L-1 ve 0.113 mg L-1 konsantrasyonlarında tribenuron metilin zebra balığı embriyo ve larva gelişimine olan etkisi incelenmiştir. Bu çalışma sonucunda tribenuron metil uygulamasının embriyo hücrelerinde toksik etki ettiği, farklı malformasyonlara sebep olduğu tespit edilmiştir.

Transcriptome analysis reveals gene responses to herbicide, tribenuron methyl, in Brassica napus L. during seed germination

BackgroundTribenuron methyl (TBM) is an herbicide that inhibits sulfonylurea acetolactate synthase (ALS) and is one of the most widely used broad-leaved herbicides for crop production. However, soil residues or drifting of the herbicide spray might affect the germination and growth of rapeseed, Brassica napus, so it is imperative to understand the response mechanism of rape to TBM during germination. The aim of this study was to use transcriptome analysis to reveal the gene responses in herbicide-tolerant rapeseed to TBM stress during seed germination.Results2414, 2286, and 1068 differentially expressed genes (DEGs) were identified in TBM-treated resistant vs sensitive lines, treated vs. control sensitive lines, treated vs. control resistant lines, respectively. GO analysis showed that most DEGs were annotated to the oxidation-reduction pathways and catalytic activity. KEGG enrichment was mainly involved in plant-pathogen interactions, α-linolenic acid metabolism, glucosinolate biosynthesis, and phenylpropanoid biosynthesis. Based on GO and KEGG enrichment, a total of 137 target genes were identified, including genes involved in biotransferase activity, response to antioxidant stress and lipid metabolism. Biotransferase genes, CYP450, ABC and GST, detoxify herbicide molecules through physical or biochemical processes. Antioxidant genes, RBOH, WRKY, CDPK, MAPK, CAT, and POD regulate plant tolerance by transmitting ROS signals and triggering antioxidant enzyme expression. Lipid-related genes and hormone-related genes were also found, such as LOX3, ADH1, JAZ6, BIN2 and ERF, and they also played an important role in herbicide resistance.ConclusionsThis study provides insights for selecting TBM-tolerant rapeseed germplasm and exploring the molecular mechanism of TBM tolerance during germination.

Effects of Different Ammonia Levels on Tribenuron Methyl Toxicity in Daphnia magna.

The present study investigates the toxicity of the herbicide tribenuron methyl (TBM) as an anthropogenic agent and ammonia as an abiotic factor on Daphnia magna at environmentally relevant concentrations. These stressors may coexist in surface waters in agricultural regions. To achieve this objective, D. magna were exposed to TBM at a nominal concentration of 0.81μg/L in association with a low ammonia (LA) concentration of 0.65mg/L and a high ammonia (HA) concentration of 1.61mg/L in acute toxicity tests of 96-h duration and chronic toxicity tests of 21-day duration. The D. magna also were exposed to TBM, HA, and LA singly. The D. magna were analysed for various biomarkers of sublethal toxicity. Glutathione peroxidase (GPx), glutathione S-transferase (GST), cholinesterase (ChE) enzyme activities, and levels of thiobarbituric acid reactive substances (TBARS) and total protein were determined spectrophotometrically. Mitochondrial membrane potential (MMP) was analysed by microscopy with fluorescence staining. Cytochrome c and 5' AMP-activated protein kinase (AMPK) were analysed by Western blotting. Morphometric properties were examined microscopically. This is the first study in which AMPK, an indicator of intracellular energy, was measured in D. magna. GST and ChE enzyme activities and TBARS and total protein levels did not change during acute exposures (i.e., 96h) in all treatments. GPx activity increased in D. magna from the HA + TBM treatment compared with single-exposure groups. The level of cytochrome c protein was elevated in D. magna from the LA and LA + TBM treatments. AMPK protein levels increased in all treatments with daphnids, except in the LA group. MMP was depolarised in D. magna from all treatments, whereas the most notable change was observed in HA + TBM mixture group in chronic exposures. The results show that GST and ChE may not be sensitive biomarkers for evaluating the sublethal toxic effects to D. magna exposed to environmentally relevant concentrations of ammonia and TBM. Acute and chronic exposure to ammonia and TBM probably caused an energetic crisis in D. magna. Therefore, AMPK and MMP are promising biomarkers for these toxicants.

Structural and functional responses in sun spurge (Euphorbia helioscopia L.) against post‐emergence herbicides in wheat (Triticum aestivum L.)

AbstractWe investigated changes in plant morphology, anatomy and physiology in a commonly occurring weed, Euphorbia helioscopia L. due to exposure to post‐emergence herbicides. Weed plants were sprayed with one of the following herbicides: pyrimidinyl sulphonylharnstoffe (PS), tribenuron‐methyl (TM), fluroxypyr‐methyl tribenuron‐methyl (FMTM) and bromoxynil (Br). The PS treatment significantly decreased plant height, promoted initiation of side branches and induced a prostrate habit. A specific response of root anatomy to PS and Br treatments was the high proportion of storage parenchyma. The Br‐treated plants showed thickest roots with a significantly large storage parenchyma, not only in the central portion of roots, but also in the cortical parenchyma outside the vascular tissue. A high proportion of xylem in the central portion of roots in the TM or FMTM‐treated plants provides a strong survival response in E. helioscopia. Disintegration of stem cortical parenchyma is the most prominent response of E. helioscopia when treated with a herbicide like PS or FMTM. Survival against these herbicides relates to a complete ring of vascular bundles and intact cortical parenchyma outside the vascular tissue. Increased leaf thickness was recorded in most of the cases except in the FMTM‐treated plants. The PS‐treated plants showed midrib thickness with two distinct vascular bundles. The cortical region, however, was found to be damaged by tissue collapse forming a large lysigenous aerenchyma. Euphorbia helioscopia had altered morphology, anatomy and physiology in response to herbicide application, which changed its growth in the field. To achieve control of this weed species, alternative strategies or higher doses of herbicide should be applied. Further research is required to determine the interaction of surviving weed plants with the crop.

Microemulsions of tribenuron-methyl using Pluronic F127: Physico-chemical characterization and efficiency on wheat weed

Microemulsions have received particular interest as novel vehicles for drug delivery. Herein, a new tribenuron-methyl (TM) loaded oil-in-water Pluronic F127-stabilized microemulsion is developed as a promising delivery nanocarrier for herbicides to control the growth of wheat weed (Convolvulus arvensis). The diameter for the TM-loading microemulsions was determined to be 7.5 nm. Experimental results revealed a high entrapment (83% ± 6%) and loading efficiency (0.44% ± 0.07%) of TM in F127-stabilized microemulsions. The in-vitro release profile from the microemulsions ensured a controlled and sustained release of the loaded TM, with ca. 50% release of TM was achieved from the microemulsions within the first 35 h, in comparison to a complete release of free TM within the first 5 h. After 5 weeks, TM-microemulsions were able to reduce the fresh weight (76%), dry weight (55%), acetolactate synthase activity (83%), and plant height (79%) of C. arvensis in comparison with controls. Using a herbicide concentration as low as ca. 50% [15 g of active ingredient per hectare,g a.i. ha−1)], of the recommended dose of commercial herbicides (Granstar) great inhibitions of weed growth were obtained. Therefore, the present microemulsion system opens the door to new nanocarriers for effective weed control to reduce economic costs and potential pollution issues.