Lactuca Sativa Seeds Research Articles

Phytotoxicity assessment of treated vegetable oily wastewater via environmentally coagulation/flocculation and membrane filtration technologies using lettuce (Lactuca sativa) seeds.

The present investigation highlights the necessity of monitoring some basic physico-chemical water quality indicators and their phytotoxic effect using ecotoxicological bioassays such as "seed germination tests." The phytotoxicity of raw and treated vegetable oil refinery wastewater (VORW) using different treatment processes was assessed through some physiological responses (relative seed germination (RSG), seedling elongation, and germination index (GI)) using Lactuca sativa cultivar. Biotest results of different raw water samples revealed a noticeable correlation between the organic matter content and water phytotoxicity. In fact, VORW showed a very low RSG (17 ± 0.7 to -47 ± 0.58%) and high phytotoxic effects (GI < 50%). The use of coagulation/flocculation (CF) allowed a satisfactory phytotoxicity removal where RSG obtained ranged from 83 ± 1.58 to 90 ± 1.2%. However, the effluent still presents high to moderate phytotoxicity since GI remained below 80% which indicates the presence of toxic elements remaining after CF treatment. When VORW were treated using membrane processes, their phytotoxicity was gradually decreased with the decrease in the membrane pore size. The use of microfiltration membranes (MF), with pore size of 5 µm, 1.2 µm, 0.45 µm, and 0.22 µm, showed RSG values ranged from 37 ± 1.15 to 77 ± 1.68% and GI of less than 80% indicating a moderate to high phytotoxicity. However, the use of ultrafiltration (UF) membranes with molecular weight cut-off (MWCO) of 100 kDa, 30 kDa, and 10 kDa made it possible to achieve an RSG of 100% and an IG exceeding 80% showing that the VORW-treated using UF does not exhibit any phytotoxicity effect. Hence, UF appears to be the most efficient and environmentally friendly technology that could be used for safely treated VORW irrigation purposes compared to CF and MF processes.

Study on the auxin-like activity of organic compounds extracted from corn waste hydrochar prepared by hydrothermal carbonization

ABSTRACT This work studied the auxin-like activity of liquid and solid hydrochar from aboveground corn biomass prepared using hydrothermal carbonization (HTC). Understanding the action of organic compounds in regulating plant metabolism is important to develop strategies to improve plant growth and production. Bioassays were performed by testing liquid hydrochar concentrations in the range of 0.0557-5570.0 mg carbon L−1; and solid hydrochar (via extracted dissolved organic matter, DOM) in the range of 0.026-2600.0 mg carbon L−1, using seeds of Lactuca sativa. SEM, ATR-FTIR, and Py-GC/MS were applied to assess the effect of HTC on hydrochar production/composition. Liquid hydrochar presented an intense bioactivity, completely inhibiting the germination of testing seeds at higher concentrations. Liquid hydrochar also was considerably more bioactive. Py-GC/MS allowed the identification of the molecules involved in IAA-like effects: carboxylic acids (linear and aromatic) and amino acids. The concentration of more bioactive molecules, rather than their simple presence in the hydrochar fraction, determined the bio-stimulating effect, besides an excellent linear regression between the auxin-like effect and the concentration of active molecules.

The allelopathic effects of aqueous Talinum triangulare (jacq.) willd extracts on the development of Lactuca sativa L. seedlings.

Plants that produce allelopathic compounds against weeds have emerged as a potential solution for the development of ecologically correct bioherbicides. Talinum triangulare is noteworthy in this regard, as its phytochemical composition encompasses flavonoids, alkaloids and other metabolites that can be used to develop inhibitory weed growth solutions. Lactuca sativa (lettuce) has been widely applied as a bioindicator species for bioherbicides and several chemicals, animal waste, water and soil quality, and atmospheric contamination, among others. In this context, this study aimed to assess the potential allelopathic effect of aqueous T. triangulare extracts on the development of L. sativa seedlings. A completely randomized design employing a 2x4 factorial scheme (shoot and root extracts) x the concentration of each extract (0, 2.5, 5, 7.5%) was applied, comprising four replications. Lactuca sativa seeds were sown on germitest papers soaked with the extracts in a germination chamber at 20°C. Physiological seed evaluations comprising the germination test, where normal and abnormal seedlings are counted on the seventh day after sowing, first normal seedling counts on the fourth day after sowing, and seedling and root length measurements. At the end of the germination test, L. sativa seedlings were separated for morphoanatomical characterizations and chlorophyll a fluorescence analyses. The T. triangulare extracts significantly influenced L. sativa root growth, with shoot extract exposure leading to more abnormal plants and lower root lengths at increasing concentrations and compared to the root extract. Root extract exposure led to evident cellular changes and lower non-photochemical quenching and unregulated dissipation quantum yields at a 5% exposure dose compared to shoot extract exposure. These findings suggest that both aqueous T. triangulare root and shoot extracts from 5% exposure doses exhibit high potential as bioherbicides, acting directly on plant structure, anatomy, quality, size and physiology.

Evaluation of an eco-friendly botanical extract against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and its composition

The red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae), is one of the most damaging grain insect pests in the storage products industry. The acquired resistance to synthetic pesticides and the high toxicity of these compounds on non-target organisms have led to an increase in the search for biopesticides. Thus, the present study aimed to analyze, for the first time, the chemical composition of the extract of Crotalaria stipularia Desv. seeds and its insecticidal activity against T. castaneum adults. Therefore, the crude extract (5 % w/v) of C. stipularia seeds was performed in a 50 mM Tris − HCl pH 8.0. Lectin and secondary metabolites such as flavones, flavonols, xanthones and saponins were detected in the extract. The extract (10 % w/v) of C. stipularia caused 100 % mortality against T. castaneum insects and exhibited moderate deterrent activity, resulting in a 70 % reduction in food consumption compared to their normal intake. Furthermore, the aqueous extract exerted antinutritional effects, interfering with the metabolism of proteins, cholesterol, triglycerides and carbohydrates, and abolished the hatching of eggs of the treated insects. The phytotoxicity test revealed that the extract of C. stipularia is not toxic to non-target organisms, as it did not affect the germination of lettuce (Lactuca sativa) seeds. These results support the search for integrated management strategies for the control of T. castaneum using a new biomaterial obtained from C. stipularia seeds.

Solar photocatalysis using post-consumer alkaline batteries for degrading contaminants of emerging concern in surface water

The goal of this study was to explore the use of post-consumer alkaline batteries' electrolytic paste as photocatalysts in solar processes for degrading contaminants of emerging concern (CECs) in surface water. Two types of alkaline batteries were used: Super Hyper UM-3SHSL8P6 (SH) and Alkaline LR6XAB/4B192 (AK), which were calcined at 500 °C for 4 h. The materials underwent various characterization tests, including SEM, XRF, BET, DRS, TGA, DRX, and pH at the Isoelectric Point (pI). The initial pH and catalysts dose conditions that result in the highest efficiency of methylene blue degradation were achieved through central composite design (CCD), i.e., 11.2, a dose of 1.5 g L−1 for AK and 1.6 g L−1 for SH. After 2 h of exposure to natural solar radiation, SH and AK achieved 72.6% and 96.6% removal efficiency in degrading the methylene blue model substance, respectively. This optimal condition was validated experimentally and statistically. In recycling tests, the photocatalysts maintained their efficiency until the third cycle with no statistically significant differences. The toxicity test with Lactuca sativa (lettuce) seeds showed that the treated water was not toxic. The AK catalyst was tested in the presence of three pharmaceutical drugs (ciprofloxacin, acetaminophen, and carbamazepine) in surface water at optimal pH 11.2 and natural pH (∼7), resulting in an overall removal of approximately 41.3% and 30.6%, respectively. Overall, our findings demonstrate that post-consumer alkaline batteries' electrolytic paste can be a viable option for solar heterogeneous photocatalysis under well-adjusted conditions.

Application of Mobile Fluorescence Spectroscopy as a Method in the Determination of Varietal Differences in Lettuce (Lactuca Sativa) Seeds

Application of Mobile Fluorescence Spectroscopy as a Method in the Determination of Varietal Differences in Lettuce (Lactuca Sativa) Seeds

Actividad insecticida y fitotóxica del aceite esencial de Eryngium foetidum L. colombiano

Eryngium foetidum L. is a biennial herb belonging to the family Apiaceae, which is used extensively as a medicinal plant in most tropical regions. In this research work, the activity of the essential oil (EO) from E. foetidum against the Hyalomma lusitanicum Koch, and its phytotoxicity in germination of seeds of Lolium perenne and Lactuca sativa was studied. E. foetidum EO was isolated by the hydrodistillation technique. Gas chromatography coupled to mass spectrometry (GC-MS) was used to identify the volatile metabolites. Fifteen compounds were found in the E. foetidum EO. The major compounds were E-2-dodecenal (53.0%), trimetilbenzaldehyde (duraldehyde) (14.8%), cyclododecane (4.4%), trans-tetradec-enal (3.9%), decanal (3.6%), and trans-2-dodecen-1-ol (3.0%) and D-limonene (1.5%), respectively. The E. foetidum EO, and two of its individual main compounds (2-dodecenal, and duraldehyde) had low phytotoxic activity when were compared with the percentage of inhibition of germination of the control (carvone), in seeds of L. perenne and L. sativa. The acaricidal activity against Hyalomma lusitanicum was determined using a probit analysis (P&gt;0.05). The essential oil of E. foetidum showed 100% mortality on H. lusitanicum at a concentration of 10 µg µL-1, and LC50 = 4.2 µg µL-1. The results obtained from the essential oil of E. foetidum show a great potential to develop natural biocides for the control of H. lusitanicum due to its chemical composition rich in aldehydes and benzene derivatives, and without adverse phytotoxic effects.

Synthesis, characterization, and reusability of novel nanobiocomposite of endophytic fungus Aspergillus flavus and magnetic nanoparticles (Fe3O4) with dye bioremediation potential

The incorrect disposal of textile dyes, such as Reactive Black 5 (RB5), causes several problems for living beings and the quality of the environment. Nanobiocomposites (NBC) produced from endophytic fungi (potentially remediation dyes-agents) and magnetic nanoparticles have high biotechnological potential due to their superparamagnetic behavior, which would allow their recovery through the magnetic field after the bioremediation process. This work aimed to obtain a new nanobiocomposite from the interaction of magnetite nanoparticles (Fe3O4) with the endophyte Aspergillus flavus (Af-CL-7) to evaluate its bioremediation capacity and to reduce the toxicity of RB5 and its reuse. Before obtaining the NBC, Af-CL-7 showed discoloration of RB5 and it was tolerant to all tested concentrations of this dye. The discovery of the nanobiocomposite textile dye bioremediator product presents a significant environmental advantage by addressing the issue of water pollution caused by textile dyes. The NBC called Af-Fe3O4 was successfully obtained with the magnetized endophyte, and their magnetic properties were verified by VSM analysis and by action of magnetic fields generated by Nd-Fe-B magnets SEM analyzes showed that the nanoparticles did not cause any damage to the hypha morphology, and TEM analyzes confirmed the presence of nanoparticles in the fungus wall and also inside the cell. The NBC Af-Fe3O4 and Af-CL-7 showed, respectively, 96.1% and 92.2% of RB5 discoloration in the first use, 91.1% e 86.2% of discoloration in the validation test, and 89.0% in NBC reuse. In the toxicological bioassay with Lactuca sativa seeds, NBC showed a positive reduction in the toxicity of RB5 after treatment, allowing the hypocotyl growth to be statistically similar to the control with water. Thus, we highlight the promising obtaining process of NBC that could be applied in bioremediation of contaminated waters, wherein the industrial economic cost will depend on the fermentation efficiency, biomass production and nanoparticle synthesis.

Effect of crystalline phase of MnO2 on the degradation of Bisphenol A by catalytic ozonation

In recent decades, manganese oxide (MnO2) has been an attractive catalyst for organic pollutants removal from wastewater by ozonation. However, the effect of the MnO2 crystalline phase on Bisphenol A ozonation in water has never been investigated. In the present study, three crystalline phases of MnO2 were synthesized by hydrothermal method, including α-, γ-, and δ-MnO2, the last generating three different kinds. The as-prepared MnO2 were evaluated in the ozonation of Bisphenol A (BPA) and correlated with their physicochemical properties obtained by different characterization techniques. The activity of MnO2 polymorphs for TOC removal followed the order of γ-MnO2 > δ3-MnO2 > δ1-MnO2 > α-MnO2 > δ2-MnO2. The catalytic activity of MnO2 strongly depended on the presence of active sites such as density of the surface oxygen vacancy, Mn+3/Mn+4 ratio, and OH-groups on the catalyst surface. The catalysts with the highest amount of oxygen vacancies (but the minor density of the surface oxygen vacancy) and OH-groups were δ3-MnO2 and γ-MnO2, respectively, demonstrating excellent catalytic activity on BPA removal. The effect of stabilities of δ3-MnO2 and γ-MnO2 was also investigated in this research. Furthermore, the toxicity bioassay based on Lactuca sativa seeds demonstrated that by-products generated during conventional and catalytic ozonation were non-toxic. The elimination of the model mixture of emergent compounds in four types water were also tested with δ3-MnO2 and γ-MnO2, obtaining mineralization values around 47–59 % and 40–55 %, respectively, at 120 min compared with 18–23 % of conventional ozonation.

Influence of different concentrations of plasticizer diethyl phthalate (DEP) on toxicity of Lactuca sativa seeds, Artemia salina and Zebrafish

Like other phthalates, diethyl phthalate (DEP) is considered as a contaminant of emerging concern (CEC) due to its ease in migrating from a package to water and food, and hence contaminate consumers, being metabolized and excreted in the urine. Its presence has a negative impact on aquatic ecosystems, especially with respect to disruption of the endocrine system and to reproductive disorders in humans. It mainly enters water bodies via sewage effluents from effluent treatment plants, due to its incomplete or inefficient removal. The objective of this work was to evaluate the toxicity of DEP at different trophic levels and to analyze data on the incidence and concentration of DEP according to its solubility. The concentrations ranged from 12.5 mg L−1 to 500 mg L−1 considering the response for toxicity at each trophic level and to determine the lethal concentration in 50% of the following organisms (LC50) (in mg L−1): Lactuca sativa seeds, Artemia salina Leach nauplii and Zebrafish embryo larval stage (Danio rerio), being 41,057.58 after 120 h; 401.77 after 48 h; and 470 after 96 h of exposure, respectively. As expected, higher organisms were more affected even at low concentrations, which shows the anthropological contribution of CECs to water bodies.

Characterization and Germination Performance of Lettuce Sativa by Iron Oxide Nanoparticles Seed Priming

Increasing food availability and ensuring food security have become critical issues for nations with varying levels of economic growth. The agricultural sector plays an essential role in these developments. To cater to this, seed priming is a typical method for controlling the hydration of seeds, ensuring that the plant can consume water and proceed to the initial stage of germination. The main objective of this research is to characterise the synthesis of chemical iron oxide nanoparticles (FeNPs) and investigate the germination performance of Lactuca sativa (lettuce). Iron oxide (Fe) is important for various processes in plants, such as photosynthesis. The chemical method was chosen to synthesise the nanoparticles as it can reduce the overall cost, has a high yield, and is safe for the environment. In this experiment, two salt solutions were chosen as the reducing agents for the chemical method. The effect of seed priming with different concentrations of FeNPs (1, 2, 4, 6, 8, and 10 ppm) on seedling growth parameters such as germination rate and average shoot and root length varieties was studied on the fifth and eighth days of seedling development. Seed priming with FeNPs increased the germination rate more than control at all studied concentrations. As a result, among the 5 different concentrations, 1 ppm shows an increase in germination rate, average length of root of Lactuca sativa (lettuce) seeds, and shoot better than the others. The germination rate of 1 ppm is 80%, compared to the control at 70%. Seed priming with FeNPs was nontoxic in comparison to the control, but it decreased the amount of chlorophyll and can be used to increase the nonenzymatic antioxidant capacity during the early phases of Lactuca sativa (lettuce) seedling development. Overall, this study suggests that using FeNPs to prime the seeds of Lactuca sativa (lettuce) can potentially increase crop yield and help keep the demand for food production stable.

The Essential Oil of Petroselinum crispum (Mill) Fuss Seeds from Peru: Phytotoxic Activity and In Silico Evaluation on the Target Enzyme of the Glyphosate Herbicide.

Petroselinum crispum (Mill) Fuss is an aromatic plant belonging to the Apiaceae family and used in gastronomy as a spice. Several studies have been developed in leaves but studies are limited in seeds, especially the essential oils obtained from seeds. The aim of this study was to determine the phytochemical profile of the volatile compounds of this essential oil by gas-chromatography-mass spectrometry (GC-MS) in order to evaluate its phytotoxic activity on Lactuca sativa seeds and to carry out an in silico analysis on the target enzyme of the herbicide glyphosate 5-enolpyruvylshikimate 3-phosphate synthase (EPSP). The essential oil was obtained by steam distillation for two hours and then was injected into a GC-MS, the phytotoxic assay was carried out on Lactuca seeds and the in silico evaluation on the EPSP synthase focused on the volatile compounds similar to glyphosate, docking analysis, and molecular dynamics to establish the protein-ligand stability of the most active molecule. The chromatographic analysis revealed 47 compounds, predominated by three compounds with the most abundant percentage in the total content (1,3,8-ρ-menthatriene (22.59%); apiole (22.41%); and β-phellandrene (15.02%)). The phytotoxic activity demonstrated that the essential oil had a high activity at 5% against L. sativa seed germination, inhibition of root length, and hypocotyl length, which is comparable to 2% glyphosate. The molecular docking on EPSP synthase revealed that trans-p-menth-6-en-2,8-diol had a high affinity with the enzyme EPSP synthase and a better stability during the molecular dynamic. According to the results, the essential oil of P. crispum seeds presented a phytotoxic activity and might be useful as a bioherbicide agent against weeds.

Biological treatment of leachate from the uncontrolled landfill: evaluation of toxicity and heavy metals reduction

ABSTRACT This work assesses the efficiency of biological processes in reducing leachate toxicity, using tests of phytotoxicity, cytotoxicity and heavy metals assay. Concerning metal load of raw leachate, iron is the most abundant with a value of 77.23 mg/L; combined treatment is most effective in reducing metals with abatement rates of: Al (94.96%), Fe (99.23%), Pb (90.53%), Sn (90.25%) and Zn (90.43%). The phytotoxicity of raw leachate is total against all tested seeds, this phytotoxicity was decreased after treatment with SBR, and the germination indices are between 3.60%−65.36%, 0.25%−39.99% and 5.36%−35.55% respectively for Daucus carota, Lactuca sativa and Hordeum vulgare seeds. Leachate treated with the combined treatment exhibits no inhibition of germination even at concentrations of 100%. Regarding cytotoxicity assessed via Brine Shrimp test, raw leachates were cytotoxic killing all Artemia salina larvae even at low concentration of 1%. After the treatments, cytotoxicity of leachate was decreased especially in leachate treated by SBR and combination with inhibition percentages up to 16.66%. The experimental results obtained were confirmed using PCA which showed that the SBR and combination treatments have common purification characteristics and also the inverse correlation between heavy metal concentrations and germination indices indicate that these metals are involved in leachate toxicity.

Piper nigrum allelopathy on the germination and initial growth of Lactuca sativa and Panicum maximum

The increased demand for food promotes greater use of agricultural inputs and pesticides used in pest control. Many of these products have negative environmental and public health impacts. Thus, there is a need for alternative products, with allelopathic capacity that reduce such impacts. The objective of this work was to verify the allelopathic potential of Piper nigrum L. extracts on the germination and initial growth of Panicum maximum Jacq. and Lactuca sativa seeds. The experimental design used was completely randomized, using two plant organs (leaf and seed), three extractors (hexane, ethyl acetate and methanol) and five concentrations (0 mg/L, 200 mg/L, 400 mg/L, 600 mg/L and 800 mg/L). It was verified the influence of these extracts on germination speed index (IVG), germination percentage (G), mean germination time (TMG), allelopathy index (IA), shoot growth (CPA) and in the root growth (CR) of seeds and seedlings. The leaf and seed extracts, at all concentrations and extractors tested, did not show phytotoxicity or had a very small inhibitory effect on germination and initial growth of Lactuca sativa. For Panicum maximum, ethyl acetate and methanol seed extracts, at the highest concentrations tested, had the most significant negative effects on the weed. Thus, it was possible to infer that extracts from Piper nigrum seeds have potential use in the control of the weed Panicum maximum.

Effect of eucalyptus saponin and sophorolipid amendment on soil and sediment microbial communities and seed germination: potential application for PAH bioremediation

PurposeThe potential toxic effects due to the application of sophorolipid and the novel saponin biosurfactant extracted from the leaves of Eucalyptus camaldulensis for the purpose of bioremediating PAH-contaminated soils and sediments were studied.MethodsThe phytotoxic effects of sophorolipid and eucalyptus saponin were determined based on the seed germination assays carried out using the seeds of Lactuca sativa L and compared with commonly used rhamnolipid and Tween 20 surfactants. Further, biosurfactant-induced changes in soil/sediment bacterial structure and diversity were investigated by conducting Miseq amplicon sequencing of the bacterial genes.ResultsGermination indices (GI) demonstrated the non-phytotoxic effects (GI > 80%) of saponin and sophorolipid biosurfactants (100–500 mg/L), while rhamnolipid demonstrated greater phytotoxicity than Tween 20 at high concentrations (500 mg/L). Saponin-amended soil resulted in greater bacterial diversity and richness compared to controls, while sophorolipid produced the opposite effect. These significant variations were not observed in sediment samples. Incubation of biosurfactants for 20 and 40 days did not result in significant changes in bacterial diversity and structure in any of the samples. Increased abundance of some of the PAH-degrading bacteria was noted at OTU level, in the presence of saponin and sophorolipid. Saponin had less impact on native soil/sediment bacteria relative to sophorolipid based on the prevalence of the significantly shifted OTUs.ConclusionAs saponin and sophorolipid were shown to have no adverse impacts on the microbiome, and non-phytotoxic effects, their sustainable applications to remediate PAH-contaminated soils and sediments can be recommended.

Volatile Components, Antioxidant and Phytotoxic Activity of the Essential Oil of Piper acutifolium Ruiz & Pav. from Peru.

Piper acutifolium Ruiz & Pav is known as "matico" and belongs to the Piperaceae family, and in Peru it is traditionally used as an infusion or decoction to ameliorate wound healings or ulcers. In this study, the aim was to investigate the volatile components, the antioxidant profile, and the phytotoxic activity of the essential oil (EO) of P. acutifolium from Peru. To identify the phytoconstituents, the EO was injected into a Gas Chromatography-Mass Spectrometry (GC-MS) to obtain the chemical profile of the volatile components, followed by the antioxidant activity carried out by the reaction with three organic radicals (2,2-diphenyl-1-picrylhydrazyl (DPPH); 2,2'-azinobis-(3-ethylbenzothiazoline)-6- sulfonic acid (ABTS); ferric reducing/antioxidant power (FRAP)). Finally, the phytotoxic capabilities of the EO were tested on two model plants, Lactuca sativa seeds and Allium cepa bulbs. As a result, the analysis identified α-phellandrene as its main volatile chemical at 38.18%, followed by β-myrcene (29.48%) and β-phellandrene (21.88%). Regarding the antioxidant profile, the half inhibitory concentration (IC50) in DPPH was 160.12 ± 0.30 µg/mL, for ABTS it was 138.10 ± 0.06 µg/mL and finally in FRAP it was 450.10 ± 0.05 µg/mL. The phytotoxic activity demonstrated that the EO had high activity at 5% and 10% against L. sativa seed germination, the inhibition of root length, and hypocotyl length. Additionally, in A. cepa bulbs, the inhibition root length was obtained at 10%, both comparable to glyphosate, which was used as a positive control. The molecular docking on 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) revealed that α-phellandrene had -5.8 kcal/mol, being near to glyphosate at -6.3 kcal/mol. The conclusion shows that the EO of P. acutifolium presented antioxidant and phytotoxic activity and might be useful as a bioherbicide in the future.

Oregano essential oil and its main components Thymol and Carvacrol as alternatives to control citrus canker

Plant Essential Oils and their constituents are well-known for their properties as antimicrobial agents and are labeled as Generally Recognized as Safe (GRAS), prompting studies around their usage in the control of food-borne microorganisms and phytopathogens. In this study, we evaluated Oregano Essential Oil (OEO), Thymol (THY) and Carvacrol (CAR) for the control of Xanthomonas citri subsp. citri (X. citri). In vitro antibacterial assays revealed that CAR and THY inhibit X. citri growth at the concentrations of 100 µg.mL-1 and 114 µg.mL-1, lower than OEO (136 µg.mL-1). Bactericidal effects were observed at 400 µg.mL-1 for OEO and 200 ug.mL-1 for CAR and THY. Investigating potential cellular targets for the compounds showed that after 30 minutes of exposure up to 84% of the cells had their membranes disrupted, implicating the membrane as the primary target. Phytotoxicity evaluations using Lactuca sativa and Solanum lycopersicum seeds showed an acute toxic effect in all treatments above 200 µg.mL-1, except for OEO and THY in S. lycopersicum at lower concentrations. Regarding their protective effect on citrus leaves, CAR showed no effect when compared to the untreated control (0.39 and 0.50 lesions per cm2, respectively). OEO and THY were able to reduce significantly citrus canker symptoms (0.18 and 0.11 lesions per cm2, respectively). In addition, no toxic effects were observed on citrus leaves in all treatments. THY inhibits X. citri growth and the development of citrus canker lesions. These results show that THY as a viable alternative to be used in citrus canker management.

Application of TiO2 nanoplates anatase [001] impregnated on Luffa Cylindrica for biostimulation of biogas production from cassava wastewater

Anaerobic digestion (AD) has been intensively applied in the treatment of effluents, as it allows the recovery of energy and value-added chemical products. However, limitations such as the reduction of the biomass hydrolysis rate can affect the performance of the process. Thus, the addition of nanoparticles (NPs) with the reactive surface area can favor the metabolism of microorganisms, resulting in the rapid conversion of organic matter into bioenergy. However, the recovery of these NPs and their possible reuse in AD stands out as a limitation not yet evaluated. Consequently, this study explored the interrelationship of the addition of TiO2 nanoplates anatase [001] impregnated on Luffa Cylindrica (LufTiO2) and the reuse of this nanocatalyst (LufTiO2R) in the production of biogas from cassava wastewater. The results showed that the addition of (LufTiO2 and LufTiO2R) caused a reduction in the system delay time and an increase in biogas production by stimulating microbial metabolism. The batches LufTiO2 and LufTiO2R started the stabilization of biogas production from the 5th day of AD, the period in which the pH presented values lower than 4. Differently, the Control and LufTiO2P25 stabilized the biogas production on the 19th day. The COD reduction was noted in the following order: LufTiO2 (39%) > LufTiO2R (34%) > LufTiO2P25 (33%) > control (30%), suggesting the presence of organic acids in the digested materials and hydrogen in the biogas produced. After ecotoxicological evaluation of the digested materials, it was observed that the presence of these compounds formed during the acidogenic phase caused the lethality of Lactuca sativa seeds in all samples with a concentration above 6.25%. Therefore, the results highlight the potential for the application and reuse of TiO2 nanoplates anatase [001] through the combination of nanotechnology and natural fibers as a promising method to stimulate the production of biogas from cassava wastewater.

Efeito materno na tolerância à termoinibição em sementes de alface

Abstract The objective of this work was to evaluate the occurrence of the maternal effect on thermotolerance in lettuce (Lactuca sativa) seeds, as well as to find an enzymatic marker for this trait in lettuce seedlings. Seeds from the Everglades thermotolerant cultivar, the Verônica susceptible cultivar, and their reciprocal hybrids were used. For each cultivar and reciprocal hybrid, germination percentage and vigor (germination speed index) tests were carried out at 20 and 32°C. Thermotolerance was defined as the capacity to germinate at 32°C. To obtain markers that could be associated with thermotolerance, enzymatic tests were performed. The bands of the electrophoretic enzymatic extracts were quantified using the ImageJ software. The hybrids behaved similarly to their female genitors. When cultivar Verônica was the female genitor, hybrid seeds did not germinate at high temperatures and showed a lower expression of the esterase enzyme. However, when the female genitor was the Everglades cultivar, hybrids showed a high germination at high temperatures and a greater esterase expression. Therefore, there is a maternal effect on tolerance to thermoinhibition in lettuce seeds, and the esterase enzyme can be used as a selective marker to identify homozygous progenies for this trait.

Pre-emergent bioherbicide potential of Schinus terebinthifolia Raddi essential oil nanoemulsion for Urochloabrizantha

Essential oils are natural products capable of being used as novel agrochemical products. In order to fill knowledge gaps, this work evaluates the bioherbicidal potential of Schinus terebinthifolia fruit essential oil (EOsST) emulsions on germination parameters of Lactuca sativa and Urochloa brizantha seeds. The hydrodynamic size distribution of the emulsions was evaluated by dynamic light scattering (DLS), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). Also, the chemical composition of EOsST was performed by gas chromatography coupled to mass spectrometry (GC-MS). DLS results suggest nanoemulsion (NE) particle sizes smaller than 735 nm and SEM images showed spherical and cuboid shapes. FTIR spectra indicate peaks at 1640 cm−1 and 1440 cm−1, referring to the benzene ring, and the C–H stretching band from 2970 cm−1–2870 cm−1 indicates the interaction between EOsST and TX-100. GC-MS reveals that the major compounds present on EOsST were α-pinene, germacrene-D, and β-pinene. U. brizantha seed germination was reduced at doses >2 mg mL−1 and completely inhibited at 32 mg mL−1. For L. sativa there was a reduction in germination which was dose-dependent and no dose caused total inhibition. Moreover, a decrease in photosynthetic pigments, flavonoids, phenolics, and total tannins was observed. Enzyme activity was altered, with reduction to catalase and peroxidase.