Phytotoxic Effects Research Articles

The effects of Selenium phytotoxicity on two wheat (Triticum aestivum) cultivars differing in Se tolerance and the role of antioxidant enzymes in the tolerance mechanism

Abstract Wheat seedlings were hydroponically grown in Hoagland solution containing various levels of Se. Tolerance response to Se toxicity was investigated by determining the level of thiobarbituric acid reactive substance (TBARS), proline and chlorophyll content, the growth parameters, and the activity of antioxidant enzymes. The toxic level of Se treatment significantly retarded the seedling growth. A substantial amount of proline accumulation was also observed in response to toxic Se concentration, but it was more pronounced in putative-sensitive cultivars. Chlorophyll content significantly decreased in Se-intoxicated seedlings and increased at the lowest Se dose in both cultivars. Severe and mild chlorosis was observed in putative-sensitive and tolerant cultivars at the highest Se level. Alterations in the activities of glutathione reductase (GR, 1.6.4.2), glutathione S transferase (GST, 2.5.1.18), guaiacol peroxidase (GPX, 1.11.1.7), catalase (CAT, 1.11.1.6), and ascorbate peroxidase (APX, 1.11.1.11) and superoxide dismutase (SOD, EC 1.15.1.1) were determined. TBAR level did not significantly increase in putative tolerant cultivars as an indicator of membrane lipid peroxidation. However, a significant increase was observed in putative-sensitive cultivars in response to higher selenium concentrations. In higher Se treatment groups, CAT and GST activities significantly increased in putative Se tolerant cultivars. However, excluding SOD, the activity of all the studied enzymes was increased considerably in putative-sensitive cultivars in a dose-dependent manner. Higher antioxidant enzyme activities and a substantial amount of proline accumulation did not significantly contribute to overcoming Se phytotoxicity in wheat seedlings grown in media supplemented with toxic selenium levels.

Early prediction of maize resistance to nicosulfuron using hyperspectral imaging and deep learning: Method and mechanism

Inappropriate use of herbicides in agricultural fields can result in significant phytotoxic effects on maize, adversely affecting both yield and quality. The development of herbicide-resistant maize varieties is a crucial strategy for managing herbicide-related challenges in agriculture. However, traditional methods for screening resistant strains are often time-consuming and inefficient, presenting several limitations. Consequently, there is a pressing need for a rapid and precise methodology to evaluate herbicide resistance in maize. This study involved a field trial to evaluate herbicide resistance in maize, utilizing two resistant and two sensitive varieties. We developed an ATT-RES model using hyperspectral data from maize leaves subjected to herbicide stress to predict resistance. The model’s accuracy and generalizability were confirmed by integrating datasets across different years, planting seasons, and varieties. Additionally, this study examined the correlation between leaf spectra and corresponding physiological and biochemical indicators under herbicide stress by constructing a regression model and investigated the mechanisms through which spectra can predict herbicide resistance in maize. The findings indicate that on the fourth day after herbicide treatment, the model’s predictive accuracy exceeded 90 %. The accuracy peaked on the seventh day, achieving up to 95 %. The ATT-RES-based transfer model attained prediction accuracy of 93.55 %, 90.63 %, and 95.86 % across various years, varieties, and seasons, respectively. The results presented here offer significant advantages over traditional models such as Support Vector Machines (SVM), Multilayer Perceptrons (MLP), and AlexNet. Furthermore, we employed Partial Least Squares Regression (PLSR) to analyze the relationship between leaf physiological-biochemical parameters and spectral data. The analysis revealed significant correlations between the spectra and key biochemical markers: glutathione (GSH, Rp2 = 0.59), malondialdehyde (MDA, Rp2 = 0.48), chlorophyll content (SPAD, Rp2 = 0.82), and water content (WC, Rp2 = 0.71). The prediction of resistance was primarily influenced by variations in leaf SPAD and WC, but also showed correlations with GSH and MDA levels in the leaves. This study contributes valuable theoretical and technological insights that facilitate early and precise prediction of herbicide resistance in maize. The advancements demonstrated in this research hold significant potential for improving crop management and reducing the adverse impacts of herbicides on the environment.

Phytotoxic Activity of Sesquiterpene Lactones-Enriched Fractions from Cynara cardunculus L. Leaves on Pre-Emergent and Post-Emergent Weed Species and Putative Mode of Action

Sesquiterpene lactones (SLs) are compounds that are highly produced in Cynara cardunculus leaves, known for their phytotoxic activity. This study aims to assess SL-enriched fractions’ (cynaropicrin, aguerin B, and grosheimin) phytotoxic potentials and putative modes of action, compared to an initial extract, using two approaches: first, against a panel of nine weed species in pre-emergence, and then on Portulaca oleracea L.’s post-emergency stage. The SL-enriched fractions demonstrated greater phytotoxic activity when compared with the C. cardunculus leaf initial extract. The SL-enriched fractions had higher activity at root growth inhibition over the panel tested, doubling the activity in five of them at 800 ppm. Regarding the post-emergence bioassay, the SL-enriched fractions had a higher influence on the plants’ growth inhibition (67% at 800 ppm). The SL-effects on the plants’ metabolisms were evidenced. The total chlorophyll content was reduced by 65% at 800 ppm. Oxidative stress induction was observed because of the enhancement in MDA levels at 800 ppm compared to control (52%) and the decrease in SOD-specific activity from 4.20 U/mg protein (400 ppm) to 1.74 U/mg protein (800 ppm). The phytotoxic effects of the SL-enriched fractions suggest that they could be used for a future bioherbicide development.

Relative Benefits of Aqueous Extract of Sorghum Residues with Herbicide on Weed Control and Yield of Wheat Varieties

Reducing herbicide use in agriculture is key for sustainability, addressing costs, environmental issues, and resistance problems. Using non-chemical methods like allelopathy in weed management offers a viable alternative. In this phenomenon, a field study was carried out at the Agronomy Field Laboratory (AFL) of Bangladesh Agricultural University (BAU), Mymensingh, from November 2021 to March 2022, to assess the phytotoxic effects of herbicides combined with aqueous extract of sorghum (AES) on weed management and yield of wheat. This study used three wheat varieties viz. BARI Gom (wheat)-32, BARI Gom-33, and BWMRI Gom-1 and six treatment levels such as, no weeding, recommended dose of herbicide (RDH), 90% RDH + AES (1:20 w/v), 80% RDH + AES (1:20), 70% RDH + AES (1:20), and 60% RDH + AES (1:20). The experiment followed a randomized complete block design (RCBD) with three replications. The RDH with AES and wheat variety significantly influenced weed population (WP) and dry weight (DW) of weeds. BARI Gom-32 produced the highest grain yield (GY) and other yield-contributing characteristics. The best results, including the highest numbers of tillers (NET) hill-1 (6.47), spike length (SL) (15.10 cm), number of spikelet spike-1 (NSS) (19.38), 1000-grain weight (TGW) (57.67g), GY (5.10 t ha-1), and straw yield (SY) (7.07 t ha-1) and harvest index (HI) (41.95%) were observed in plots treated with the RDH and the BARI Gom-32 variety, followed closely by those receiving 90% RDH + AES (1:20). The results demonstrate that varying concentrations of AES crop residue can effectively suppress weed growth and enhance wheat yield, suggesting that sorghum residues might be utilized to manage weeds effectively and sustainably while boosting wheat production. The study supports the potential of AES crop residue as an effective means to control weeds and significantly improve wheat yields. J Bangladesh Agril Univ 22(3): 326-334, 2024

Assessment of the Potential Phytotoxicity of Chlorpyrifos in the Wetland Macrophyte Bidens laevis (L.).

Chlorpyrifos (CPF) has been used worldwide, but its possible negative effects on macrophytes have been scarcely studied. The main goal of the present work was to assess the potential phytotoxic effects of CPF on different stages (seed and seedling) of the wetland macrophyte Bidens laevis. During the germination of seeds, stimulation of radicle growth at low concentrations of CPF (10µg/L) and inhibition of its elongation at 80µg/L CPF were observed. In seedlings, concentrations ≤ 160µg/L CPF did not exhibit adverse effects on growth after 7 days of exposure, despite the decrease of photosynthetic pigments and carotenoids observed at 40µg/L CPF compared to the control. Environmentally relevant concentrations of CPF altered neither oxidative stress biomarkers nor pigment contents in seedlings exposed for 48h, suggesting CPF would be non-toxic to B. laevis in natural scenarios.

Влияние предварительной биоконверсии пшеничной соломы в модельной природоподобной системе на продуктивность растений

Studies focused on maintaining high productivity and stability of artificial ecosystems that reproduce the processes of natural cenoses are relevant and interesting. It seems to be effective to include decomposers, detritivores and vegetative waste in model systems aimed at obtaining products. The use of earthworms as detritivores is promising because they utilize the organic matter as well as enrich the substrates with microflora including those with antagonistic and growth-stimulating activities. The aim of this study was to assess the prospects of preliminary bioconversion of wheat straw by basidiomycetes (Lentinus tigrinus and Pleurotus ostreatus) to increase the productivity of lettuce plants. The work was carried out in laboratory conditions with model systems consisting of a substrate (peat, cattle manure and wheat straw with and without bioconversion), earthworms (Eisenia fetida) and lettuce (Lactuca sativa var. crispa cultivar Credo). The leaf area, the weight of each plant (wet and dry), the productivity of lettuce plants, and the content of the main biogenic elements in the plant tissue and substrate were evaluated. The number and weight of adult worms at the beginning and at the end of the experiment, and the number of juvenile worms at the end of the experiment, the number of cocoons, as well as coprolite weight and yield were considered. A significant phytotoxic effect when straw was added into the substrate was found. The addition of straw processed by basidiomycetes (10%) in the substrate had a favorable effect on the earthworm population. Growing lettuce on substrates with bioconverted straw and with the earthworm introduction increases the content of major macronutrients (nitrogen, phosphorus, potassium) in plants. The introduction of earthworms contributed to a significant decrease in the phytotoxicity of substrates. Thus, it is possible to recommend the inclusion of fungiculture wastes (such as substrates after fruiting bodies obtaining) in green crop production systems together with the introduction of earthworms into substrates.

Secondary Metabolites from Australian Lichens Ramalina celastri and Stereocaulon ramulosum Affect Growth and Metabolism of Photobiont Asterochloris erici through Allelopathy.

In the present work, the phytotoxic effects of secondary metabolites extracted from lichen Ramalina celastri (usnic acid) and lichen Stereocaulon ramulosum (a naturally occurring mixture of atranorin and perlatolic acid, approx. 3:1) on cultures of the aposymbiotically grown lichen photobiont Asterochloris erici were evaluated. Algae were cultivated on the surface of glass microfiber disks with applied crystals of lichen extracts for 14 days. The toxicity of each extract was tested at the two selected doses in quantities of 0.01 mg/disk and 0.1 mg/disk. Cytotoxicity of lichen extracts was assessed using selected physiological parameters, such as growth (biomass production) of photobiont cultures, content of soluble proteins, chlorophyll a fluorescence, chlorophyll a integrity, contents of chlorophylls and total carotenoids, hydrogen peroxide, superoxide anion, TBARS, ascorbic acid (AsA), reduced (GSH) and oxidized (GSSG) glutathione, and composition of selected organic acids of the Krebs cycle. The application of both tested metabolic extracts decreased the growth of photobiont cells in a dose-dependent manner; however, a mixture of atranorin and perlatolic acid was more effective when compared to usnic acid at the same dose tested. A higher degree of cytotoxicity of extracts from lichen S. ramulosum when compared to identical doses of extracts from lichen R. celastri was also confirmed by a more pronounced decrease in chlorophyll a fluorescence and chlorophyll a integrity, decreased content of chlorophylls and total carotenoids, increased production of hydrogen peroxide and superoxide anion, peroxidation of membrane lipids (assessed as TBARS), and a strong decrease in non-enzymatic antioxidants such as AsA, GSH, and GSSG. The cytotoxicity of lichen compounds was confirmed by a strong alteration in the composition of selected organic acids included in the Krebs cycle. The increased ratio between pyruvic acid and citric acid was a very sensitive parameter of phytotoxicity of lichen secondary metabolites to the algal partner of symbiosis. Secondary metabolites of lichens are potent allelochemicals and play significant roles in maintaining the balance between mycobionts and photobionts, forming lichen thallus.

Investigation of phytotoxic effects of fullerene С60 with the use of Allium-test

Aim. To investigate the cytogenetic effects of water-soluble fullerene C60 with the use of Allium test. To study the influence of various concentrations of fullerene С60 on the morpho-physiological parameters of A. cepa. Methods. The influence of different concentrations of fullerene С60 (25–100 μg/ml) on the induction of root formation and their growth, as well as its cytogenetic effects on the meristematic cells of root apices, were investigated. Results. It was found that fullerene C60 at concentrations of 50 and 75 μg/ml induced root formation and stimulated root growth, though causing minor deformations. Also, it was shown that fullerene С60 disrupts the progression of various phases of mitosis in the meristematic cells of roots, along with the occurrence of chromosomal aberrations at all investigated concentrations. Conclusions. The cytogenetic effects of water-soluble fullerene C60 were investigated for the first time using the Allium-test. Both positive effects on the morphophysiological parameters of A. cepa and its genotoxicity were demonstrated, which could indicate the disruptions in the mechanisms of spindle formation.

Green synthesis of silver nanoparticles for antifungal activity against tomato fusarium wilt caused by Fusariumoxysporum

Fusarium wilt caused by Fusarium oxysporum f. sp. radicis-lycopersici is one of the most important diseases in tomatoes, resulting in severe yield loss and mycotoxin infection in food and feed. The management of Fusarium wilt is based heavily on chemical fungicides, but these chemicals have many environmental concerns. Silver nanoparticles (AgNPs) are gaining importance as emerging resistance-free alternatives of chemical fungicides. In this study, AgNPs were synthesized using the aqueous leaf extract of Viola odorata as a green approach. The antifungal activity of these biosynthesised AgNPs was evaluated in vitro against F. oxysporum using the agar well diffusion method. AgNPs were also evaluated against tomato Fusarium wilt diseases using the foliar spray method in the greenhouse. The characterization of AgNPs revealed that AgNPs were of spherical shape, crystalline in nature, and had an average size of 18 nm. In the antifungal assay, 60 mg/l AgNPs strongly inhibited the growth of F. oxysporum with a growth zone of 18 ± 0.89 mm compared to fungicide (23 ± 1.20 mm) and AgNO3 (52 ± 2.33 mm). Similarly, 60 mg/l of AgNPs when sprayed on tomato plants in the greenhouse showed a survival rate of about 80% with no observable phytotoxic effect. This study provides a first baseline to control Fusarium wilt in tomato using biosynthesised AgNPs without affecting the health of crops.

Phloretin inhibits the growth of Arabidopsis shoots by inducing chloroplast damage and programmed cell death

Phloretin is a key secondary metabolite produced by apple trees. Known for its strong antioxidant properties, this dihydrochalcone has been extensively studied in animals but less so in plants. Recently, we identified phloretin as a phytotoxic allelochemical that inhibits growth in the model plant Arabidopsis by disrupting auxin metabolism and distribution in the roots. In this study, we found that phloretin significantly hinders the growth of Arabidopsis seedlings' aerial parts after a short-term treatment (10 days) and causes their decay after long-term exposure (28 days). These effects result from ultrastructural damage in the mesophyll cells of the leaves, including chloroplast displacement and swelling, lesions, and alterations in thylakoid and cell wall organization. Interestingly, phloretin-treated plants showed a decrease in malondialdehyde levels and antioxidant enzyme activities, while hydrogen peroxide and proline levels remained unchanged. This suggests that phloretin-induced chlorosis and seedling decay are not due to oxidative stress but rather to severe chloroplast structural damage, leading to inefficient photosynthesis, starch degradation, starvation, and activation of micro- and macroautophagic processes for self-preservation. Ultimately, these processes result in programmed cell death. These new insights into the phytotoxic effects of phloretin on Arabidopsis shoots could pave the way for future research into phloretin as a potential multitarget bioherbicide and enhance our understanding of autoallelopathy in apple trees.

Hydrothermal growth of Zn2GeO4 nanorods for optical and (Photo)Catalytic applications: An experimental and theoretical study

From the material design perspective, we reported a systematic investigation based on theoretical and experimental approaches to explore the physical properties of Zn2GeO4 nanorods prepared by hydrothermal method with different zinc precursors for optical and (photo)catalytic applications. All ZGO samples exhibited uniform nanorod morphology with high purity and crystallinity. A negative zeta potential ranging from −13 mV to −16 mV have been observed for these nanorods. Bandgap values indicated variations among samples synthesized with different precursors. The photoluminescence and photocatalytic activities for these nanorods, have been attributed to the presence of oxygen vacancies on the Zn2GeO4 surfaces. Experimental evidence suggests that these surface defects favor the formation of hydroxyl radicals identified as primary reactive oxygen species responsible for the methylene blue photodegradation. Toxicity testing of photocatalytic residues showed minimal phytotoxic effect on lettuce seed (Lactuca sativa) germination. Additionally, Zn2GeO4 was utilized as an acid catalyst for synthesizing isoxazol-5(4H)-ones, resulting in an increase in the yield from 69 % to 92 % by using this catalyst in multicomponent reactions. Lastly, the theoretical efforts outlined in the study aim to enhance the comprehension of the material design with well-defined morphology using realist theoretical models for the Zn2GeO4 nanorods for the first time.

Composting Cow Dung Enriched with Vivianite (Phosphocompost) for Agricultural Use in the Balaza Lawane Locality (Far North, Cameroon)

Aims: Soils in the Far North of Cameroon are deficient in organic matter and available phosphorus, making it difficult to intensify agricultural production. This affects the yield of several crops. With this in mind, a study has been carried out to produce cow dung compost enriched with vivianite, to improve soil quality in terms of organic matter and available phosphorus, and boost agricultural production. Study Design: A study was carried out to produce cow dung compost enriched with rock phosphate (Vivianite). Place and Duration of Study: Balaza Lawane in Far North Region of Cameroon. The sowing was done on January 15, 2021 until 20 april 2021. Methodology: To this end, we produced 3 organic amendments based on cow dung (a compost and two phospho-composts containing 10 and 20% of vivianite, respectively). Monitoring and chemical characterization of each of the three was carried out. A seed germination test was also carried out, on petri dishes in a completely randomized block design repeated three times. Results: Physico-chemical analyses reveal that the soil at the Balaza Lawane site has a Sandy clay loam granulometry and an acid pH (6.8); it is low in organic matter and available phosphorus. The monitoring of the amendments showed that the temperature, the pH, and even the moisture content of the amendments changed in the same way over time. The application of vivianite powder improved the nitrogen, potassium, and phosphorus content of the phosphocomposts compared to the compost. Phytotoxicity tests showed that our various amendments had no phytotoxic effects. The 20 and 10% phosphocomposts showed higher germination index than the other treatments (157.33±16.32% and 157.01±15.32% respectively). An analysis of variance revealed a significant difference (p < 0.05) threshold. Conclusion: Compost enriched with 20% vivianite produced more available phosphorus, and showed no phytotoxicity. This phosphocompost is proving to be the most effective crop amendment on Balaza Lawane soil.

Assessing the response lettuce and arugula to MC-LR-contaminated water irrigation: photosynthetic changes and antioxidant defense.

Irrigation of crops with cyanotoxin-contaminated water poses a significant risk to human health. The direct phytotoxic effects of microcystin-LR (MC-LR), one of the most toxic and prevalent microcystin variants in water bodies, can induce physiological stress and hinder crop development and production. This study investigated the impact of environmentally relevant concentrations of MC-LR (1 to 10µg L-1) on photosynthetic parameters and antioxidant response of lettuce (Lactuca sativa L.) and arugula (Eruca sativa L.) following irrigation with contaminated water. During the 15-day experiment, lettuce and arugula were exposed to various concentrations of MC-LR, and their photosynthetic rates, stomatal conductance, leaf tissue transpiration, and intercellular CO2 concentrations were measured using an infrared gas analyzer. These results suggest that the influence of MC-LR on gas exchange in crops is concentration-dependent, with notable disruptions during exposure and recovery tendency during detoxification. Antioxidant response analysis revealed that glutathione S-transferase (GST) and superoxide dismutase (SOD) activities were upregulated during the exposure phase in the presence of MC-LR. However, GST activity decreased during the detoxification phase in both crops, although the effects of the toxin at 10µg L-1 were still evident in arugula. The internal H2O2 concentration in the crops increased after exposure to MC-LR, showing a time- and concentration-dependent pattern, with an increase during the exposure phase (days 1-7) and a decrease during the detoxification phase (days 8-15). Irrigation of lettuce and arugula with MC-LR-contaminated water affected various aspects of the photosynthetic apparatus and antioxidant responses, which could influence the general health and productivity of exposed crops at environmentally relevant microcystin concentrations. Furthermore, investigation of additional vegetable species and long-term MC-LR exposure can be crucial for understanding the extent of contamination risk, detoxification mechanisms, and other parameters affecting these crops.

Metabolomics combined with proteomics reveals phytotoxic effects of norfloxacin under drought stress on Oryza sativa

In recent decades, plants enduring abiotic stresses such as drought and chemical stresses. Currently, the mechanism of combined antibiotic and drought stress response and its impact on crop growth and food security remains poorly understood. Here, the mechanism of stress responses under the exposure of norfloxacin (NF) and drought (D) individually and in combination (DNF) were explored on rice (Oryza sativa) cultivar Hanyou73 through proteomics and metabolomic analysis. All treatments adversely affected chlorophyll fluorescence kinetics, antioxidant enzyme activities, rice grain composition and yield. The results showed that in DNF the antibiotic was accumulated 627% more than NF treatment in rice grains while in leaves there was no significant difference under both treatments. The proteomic revealed that differentially expressed identified proteins were involved in carbohydrate metabolism, amino acid metabolism, photosynthesis and mRNA binding. However, the metabolomics results showed that the abundance of metabolites related to RNA biosynthesis and amino acid metabolism were more affected. The disruptions caused in rice plant under DNF treatment become more severe, this makes it more susceptible than individual D and NF treatment. These findings improve our knowledge about the response of rice plant to cope with antibiotic contamination alone and in combination with drought.

Discovery of Two Novel Phthalide Phytotoxins from the Wheat Tan Spot Fungal Pathogen Pyrenophora tritici-repentis.

The Dothideomycete fungal pathogen Pyrenophora tritici-repentis (Ptr) is the causal agent of the tan spot disease of wheat. The proteinaceous necrotrophic effectors ToxA and ToxB are well characterized. A nonproteinaceous effector called ToxC has also been partially characterized. Ptr produces a number of other small molecular weight compounds, but these remain poorly characterized. In this study, two novel compounds, designated ToxE1 and ToxE2, capable of inducing chlorotic symptoms on wheat leaves in a cultivar-specific manner, were purified from Ptr liquid cultures. There is no evidence that these compounds correspond to ToxC. Most isolates produced ToxE1, ToxE2, or both, and both compounds were detected in infected wheat leaves. The structures of both analogues were elucidated by NMR spectroscopy and comprise a phthalide core structure with an amide moiety. We postulate that these compounds have a general phytotoxic effect and may have an ancillary role in disease development.

Multiomics Analysis of the Mechanism by Which Gibberellin Alleviates S-Metolachlor Toxicity in Rice Seedlings.

S-metolachlor is a selective pre-emergence herbicide used in dryland. However, it is challenging to employ in paddy fields due to its phytotoxic effects on rice. As a common phytohormone, Gibberellin-3 (GA3) is inferred to have the ability to alleviate herbicide phytotoxicity. This study first quantitatively verified the phytotoxicity of s-metolachlor to rice and then demonstrated the mitigative effect of GA3 on these adverse reactions. Furthermore, a transcriptome of rice seedlings subjected to different treatments was constructed to assemble the reference genes, followed by comparative metabolomics and proteomics analyses. Metabolomics revealed an enrichment of flavonoid metabolites in the group of adding GA3, and these flavonoids can eliminate ROS in plants. Proteomics analysis indicated that differential proteins were enriched in the phenylpropanoid biosynthesis pathway responsible for the synthesis of flavonoids and that the functions of most differential proteins are associated with peroxidase. The proteome, combined with the transcriptome, revealed that the expressions of proteins and genes was related to the POD activity in the group of adding GA3. It was speculated that the elimination of ROS is key to alleviating the stress of s-metolachlor on rice growth. It was inferred that the mechanism of GA3 in alleviating the phytotoxicity of the substance s-metolachlor is by increasing the activity of the POD and influencing the growth of rice seedlings through the restoration of flavonoid synthesis. In this study, we screened GA3 as a safener to alleviate the phytotoxicity of s-metolachlor on rice. On this basis, the mechanism of alleviating phytotoxicity was studied. The application range of s-metolachlor might be expanded, providing a new supplementary method for weed control and herbicide resistance management.

Impact of Different Herbicidal Treatments on Hybrid Maize: A Review

Maize (Zea mays L.) is an important cereal crop grown in the world. The living factors (insects, pests, weeds) and non-living factors (drought, salinity, heat stress) affects the yield of maize; among which weeds are considered as most destructive in decreasing the maize crop yield. Weeds negatively affect the grain yield of maize and increase the production cost of farmers. Various herbicides are used to control weeds in maize including atrazine, tembotrione etc. Atrazine is a pre-emergence herbicide used to control weeds. It is a selective herbicide used to control broad-leaved weeds and annual grasses. Tembotrione is a PoE (Post-emergence) broad spectrum herbicide used to control broad-leaved and grassy weeds in maize. This herbicide effectively reduces the density and dry weight of most of the weeds present in maize crop. Tembotrione gives lower weed index and higher weed control efficiency, when applied at 150 g ha−1 + surfactant and 125 g ha−1 + surfactant at 20 DAS. These herbicide shows no phytotoxicity effect on the crops. They are totally safe for weed control and enhance the productivity and profatibilty of the crop.

Silicon-mediated resilience: Unveiling the protective role against combined cypermethrin and hymexazol phytotoxicity in tomato seedlings

Insecticides and fungicides present potential threats to non-target crops, yet our comprehension of their combined phytotoxicity to plants is limited. Silicon (Si) has been acknowledged for its ability to induce crop tolerance to xenobiotic stresses. However, the specific role of Si in alleviating the cypermethrin (CYP) and hymexazol (HML) combined stress has not been thoroughly explored. This study aims to assess the effectiveness of Si in alleviating phytotoxic effects and elucidating the associated mechanisms of CYP and/or HML in tomato seedlings. The findings demonstrated that, compared to exposure to CYP or HML alone, the simultaneous exposure of CYP and HML significantly impeded seedling growth, resulting in more pronounced phytotoxic effects in tomato seedlings. Additionally, CYP and/or HML exposures diminished the content of photosynthetic pigments and induced oxidative stress in tomato seedlings. Pesticide exposure heightened the activity of both antioxidant and detoxification enzymes, increased proline and phenolic accumulation, and reduced thiols and ascorbate content in tomato seedlings. Applying Si (1 mM) to CYP- and/or HML-stressed seedlings alleviated pigment inhibition and oxidative damage by enhancing the activity of the pesticide metabolism system and secondary metabolism enzymes. Furthermore, Si stimulated the phenylpropanoid pathway by boosting phenylalanine ammonia-lyase activity, as confirmed by the increased total phenolic content. Interestingly, the application of Si enhanced the thiols profile, emphasizing its crucial role in pesticide detoxification in plants. In conclusion, these results suggest that externally applying Si significantly alleviates the physio-biochemical level in tomato seedlings exposed to a combination of pesticides, introducing innovative strategies for fostering a sustainable agroecosystem.

Characterization and toxicity evaluation of chitosan/ZnO nanocompoite as promising nano-biopolymer for treatment of synthetic wastewater

Nanotechnology advances wastewater treatment through the application of Nano entities that optimize contaminant removal and enhance water purification efficacy. In this study, ZnO nanoparticles (ZnO NPs) were synthesized using Klebsiella pneumoniae, subsequently, a chitosan/ZnO nanocomposite (CS/ZnO NC) was prepared for removing reactive black 5 (RB-5) dye from synthetic wastewater. The biosynthesized nanomaterials were characterized using UV–VIS, FTIR, XRD, SEM and TEM techniques. The UV–Vis absorbance peaks at 370 nm and 350 nm corresponded to the characteristic surface plasmon resonance of ZnO NPs and the CS/ZnO NC, respectively. Additionally, FTIR analysis identified the various functional groups associated with ZnO NPs and the CS/ZnO NC. XRD analysis revealed their crystallinity to be approximately 22.44 and 25.76, respectively. The SEM images of ZnO NPs and the CS/ZnO NC show hexagonal plate-like particles with sizes of 33.66 nm and 38.64 nm, respectively. Four concentrations of ZnO NPs and CS/ZnO NC (0.25, 0.5, 1, and 2 mg/mL) were evaluated for RB-5 degradation at three different levels (25, 50, and 100 mg/L). Statistical analysis showed that chitosan/ZnO NC achieved 95 % dye degradation, compared to 81 % degradation with the same amount of ZnO nanoparticles. Furthermore, a pot experiment was carried out to evaluate the phytotoxicity effects of treated wastewater on wheat (Triticum aestivum L.). Both ZnO NPs and CS/ZnO NC did not significantly affect the viability of epithelial retinal cell lines at concentrations up to 100 µg/mL, suggesting a safe cytotoxic profile within this dosage range. Overall, CS/ZnO NC proved effective for treating industrial wastewater, making it suitable for recycling in agricultural applications

Phyto-cytogenotoxic potential assessment of two medicinal plants: Davilla nitida (Vahl) Kubitzki and Davilla elliptica (A. St.-Hill) (Dilleniaceae)

ABSTRACT Humans have been using plants in the treatment of various diseases for millennia. Currently, even with allopathic medicines available, numerous populations globally still use plants for therapeutic purposes. Although plants constitute a safer alternative compared to synthetic agents, it is well established that medicinal plants might also exert adverse effects. Thus, the present investigation aimed to assess the phytotoxic, cytotoxic, and genotoxic potential of two plants from the Brazilian Cerrado used in popular medicine, Davilla nitida (Vahl) Kubitzki, and Davilla elliptica (A. St.-Hil.). To this end, germination, growth, and cell cycle analyses were conducted using the plant model Lactuca sativa. Seeds and roots were treated with 0.0625 to 1 g/L for 48 hr under controlled conditions. The germination test demonstrated significant phytotoxic effects for both species at the highest concentrations tested, while none of the extracts produced significant effects in the lettuce growth test. In the microscopic analyses, the aneugenic and cytotoxic action of D. elliptica was evident. In the case of D. nitida greater clastogenic action and induction of micronuclei, (MN) were noted suggesting that the damage initiated by exposure to these extracts was not repaired or led to apoptosis. These findings indicated that the observed plant damage was transmitted to the next generation of cells by way of MN. These differences in the action of the two species may not be attributed to qualitative variations in the composition of the extracts as both are similar, but to quantitative differences associated with synergistic and antagonistic interactions between the compounds present in these extracts.