Germination Of Lactuca Sativa Research Articles

Bio-transformation of poultry litter and activated sewage sludge to produce biomixtures for the remediation of water polluted with pesticides

The aim of this study was to formulate novel biomixtures with the ability to dissipate globally used pesticides. For this, an effective stabilization of two wastes, poultry litter and activated sewage sludge, was achieved through a combination of composting and vermicomposting, with the aid of the earthworm Eisenia fetida. Hence, two different mixtures were prepared combining the wastes with and without the addition of sewage sludge, and their physicochemical and microbiological characterization was examined during both processes. Earthworms reproduction was promoted by more than fourteen times the initial number of individuals introduced. This step made it possible to obtain substrates rich in organic matter, stable and non-pathogenic. The resulting vermicomposted substrates (V–C1 and V–C2) were used to produce two different biomixtures with wheat stubble (WS) and soil (S): SWSV-C1 and SWSV-C2, and they were tested for the remediation of a solution of five pesticides (2,4-D, cypermethrin, imidacloprid, acetochlor and dimethoate) in a 119-days assay. Comparisons were made with a WS-only biomixture (SWS) and a soil control. All biomixtures were more successful in dissipating the pesticides than soil; 2,4-D, dimethoate, and acetochlor degradation reached more than 99% in the three biomixtures after 28–56 days of assay. Biomixtures containing either vermicomposts acted faster than SWS, particularly for 2,4-D, dimethoate and cypermethrin. The total microbial activity was found to be higher in the two biomixtures containing vermicompost, which can be linked to their enhanced performance in the degradation of pesticides. Although the germination of Lactuca sativa proved that neither of the three spent biomixtures were phytotoxic at the end (germination index >60%), only SWSV-C1 and SWSV-C2 proved to be safe for the survival of E. fetida. This work confirms that vermicompost improves the success of biomixtures, not only in terms of pesticide removal, but also providing non-toxic spent biomixtures.

The Biosurfactants Mannosylerythritol Lipids (MELs) as Stimulant on the Germination of Lactuca sativa L.

The application of pesticides in agriculture leads to improved crop quality and promotes high productivity. However, the uninterrupted use of these chemicals is directly related to environmental impacts, affecting biodiversity and the health of ecosystems and humans. In this sense, mannosylerythritol lipids (MELs) are a promising alternative, as they are biosurfactants with antimicrobial, amphiphilic characteristics, and low toxicity. Thus, in search of a partial reduction in the use of chemical pesticides in agriculture, this work aimed to evaluate the biostimulant effect of one of the homologs of MELs–MEL-B on the germination of Monica lettuce seeds (Lactuca sativa L.) and the influence on plant growth and root development. The seeds germinated in different concentrations of MEL-B. The incidence of germinated seeds, the germination index, and the average germination time were evaluated. MEL-B at 158 mg/L stimulated seed germination, growth, and seedling development parameters by 65%, while concentrations of 316 and 632 mg/L did not exceed 45% for these parameters. It was observed that MEL-B at 158 mg/L biostimulated the appearance of lateral roots and promoted only 7% of root stress, a difference of 47% for roots grown with MEL-B at 632 mg/L. Furthermore, MEL-B at 158 mg/L was the highest concentration at which there was no phytotoxic effect of MEL-B on seeds. The increase in enzymatic activity corroborates the phytotoxic effect and seed stress at concentrations of 316 and 632 mg/L, showing results of 47% and 54% of stressed roots. In an unprecedented way, this study proved that MEL-B has a biostimulant and phytotoxic effect related to its concentration.

Sustainable bioprocess combining subcritical water pretreatment followed by anaerobic digestion for the valorization of jabuticaba (Myrciaria cauliflora) agro-industrial by-product in bioenergy and biofertilizer

The management of agri-food by-products has received worldwide attention due to concerns about the environmental impacts caused by incorrect deposition. This study presented a sustainable bioprocess combining subcritical water pretreatment (SWP) followed by semi-continuous anaerobic digestion (AD) for the valorization of jabuticaba (Myrciaria cauliflora) agro-industrial by-product in bioenergy and agricultural fertilizer. The SWP was conducted at 180 °C, 15 MPa, water flow rate of 10 mL min−1, solvent to feed of 22.5 g g−1, and a kinetic time of 45 min. The AD process was operated in semi-continuous mode under mesophilic and methanogenic conditions. The results demonstrated that the hydrolysate presented glucose (5.78 g L−1), fructose (3.63 g L−1), arabinose (1.82 g L−1), and cellobiose (1.28 g L−1) as major compounds. The use of pretreated jabuticaca by-product increased the methane yield (239.04 L CH4 kg−1 TVS) in the designed bioprocess combining SWP and AD when compared to the AD without pretreatment (42.31 L CH4 kg−1 TVS). The methane produced in the bioprocess with SWP followed by AD can generate 543 kWh t−1 of electricity and 2,243.17 MJ t−1 of heat, avoiding a total of 177.54 kg CO2-eq t−1. The digestate generated after AD can be used as a biofertilizer up to a concentration of 0.3 g L−1, without toxic effects on the germination of Lactuca sativa. Finally, the sustainable bioprocess designed could be an alternative to the management of jabuticaba by-product within a circular economy framework, producing bioenergy and agricultural fertilizer that can reduce greenhouse gas emissions and environmental pollution in the food industry.

Phytotoxic activity and identification of chemicals constituents in Lonchocarpus cultratus (Vell.) A.M.G. Azevedo & H.C. Lima aerial parts (Fabaceae)

Lonchocarpus cultratus (Vell.) A.M.G. Azevedo & H.C. Lima (Fabaceae) is a native tree species and from which flavonoids, triterpenes, alkaloid were isolated. In addition, potent antiproliferative activity of hexane fraction and chalcone, obtained from this plant, has been described in different cell lines of human tumors. However, no studies were found on the allelopathic and/or bioherbicidal action, using aerial parts of L. cultratus. Thus, the aim of the present work was to evaluate the allelopathic activity of methanol extract, fractions and compounds from aerial parts of L. cultratus. Dried aerial parts were extracted by exhausting extraction with methanol at room temperature, and the solvent was evaporated under reduced pressure providing the crude extract. The crude extract was partitioned in a liquid-liquid extraction and to obtain hexanic (HF), chloroform (CF), ethyl acetate (EAF), and hydromethanolic (HMF) fractions. The compounds were extracted from fractions through chromatographic methods. Crude extract and its fractions inhibited Lactuca sativa germination mean time (GMT) and germination speed índex (GSI), but not the germination percentage (GP) of Lactuca sativa. Crude extract and hexane fraction inhibited the hypocotyl growth of L. sativa seedlings and the other fractions inhibited the primary root of seedlings. Hexane, chloroform, and ethyl acetate fractions inhibited primary root growth of Euphorbia heterophylla. Chalcone 2’,4’-dihydroxy-5’-prenylchalcone, flavanone 8-prenylpinocembrin and alkaloid 4-hydroxy-N-methylproline were tested on lettuce early growth. Thirty-three metabolites were identified by UHPLC-MS/MS analysis, with flavonoid derivatives being the most abundant constituents.

Insights into the Bioprospecting of the Endophytic Fungi of the Medicinal Plant Palicourea rigida Kunth (Rubiaceae): Detailed Biological Activities.

A multitude of plants from the Brazilian savanna are known for their medicinal properties. Many plants contain endophytic fungi, which lead to the production of bioactive compounds by both the fungi and their hosts. This study investigated the bioprospecting of endophytic fungi recovered from the leaves of Palicourea rigida, a native medicinal plant of the Brazilian savanna. Four fungal taxa (Colletotrichum sp. SXS649, Pestalotiopsis sp. SXS650, the order Botryosphaeriales SXS651, and Diaporthe sp. SXS652) were recovered. The phenolic, flavonoid, extracellular degrading enzymes (amylase, cellulase, protease, and tannase) and antioxidant activity of these taxa were determined. Evaluation of the antimicrobial activity showed that the Botryosphaeriales SXS651 extract displays a minimum inhibitory concentration (MIC) of 23.20 mg mL−1 against Staphylococcus epidermidis and Pseudomonas aeruginosa, and the Diaporthe sp. SXS652 extract exhibited an MIC of 27.00 mg mL−1 against Escherichia coli. The Colletotrichum sp. SXS649 isolate inhibited tumors in potato discs by 69% at a concentration of 9.70 mg mL−1. All isolates had potential bioremediation criteria against soil contaminated with soybean oil, as proved by a high percentage of germination of Lactuca sativa and a reduction in phytotoxicity. Furthermore, the taxa under investigation demonstrated antagonistic action to phytopathogenic fungi, namely, Aspergillus niger, Inonotus rickii, Pestalotiopsis mangiferae, and Coniophora puteana, with an inhibition range between 34.2% and 76.9%. The preliminary toxicity assessment showed that all isolates possessed an LC50 of less than 100 mg mL−1 to the microcrustacean Artemia salina. These results indicate that the endophytic fungi of the Brazilian savanna are promising candidates for biotechnological and industrial applications and, in agricultural applications, for the biological control of phytopathogenic fungi.

Eco-friendly production of biochar via conventional pyrolysis: Application of biochar and liquefied smoke for plant productivity and seed germination

Abstract Conventional pyrolysis of agricultural wastes may emit considerable amounts of greenhouse gases that affect negatively the surrounding environment. A trial was done to capture the emitted gases through connecting a small water jacket with the pyrolysis unit. This plant was then used for production of biochars from two waste materials i.e. nutshell (NS-BC) and date-palm seed (DP-BC). The biochars manufactured from the aforementioned waste materials were then evaluated for their applicability vs pig manure (each amendment was applied at rates of 1, 2.5, 5 and 10%; w/w) to improve growth of Brassica chinensis grown on a sandy soil under greenhouse conditions. Collected liquefied smokes were also tested for enhancing germination of Lactuca sativa (lettuce) seeds using different concentrations (0%–5%, v/v). Results revealed that produced biochars decreased significantly soil pH where the highest reduction (14.30%) was occurred due to addition of 10% DP-BC. Moreover, NS-BC and DP-BC decreased significantly soil salinity from 0.21 dS m −1 (control) to 0.13 and 0.14 dS m −1, respectively; on the other hand, pig manure raised significantly soil salinity (10% application rate). Residual organic matter was higher in biochar amended soils than its corresponding values in pig manure treated ones. Generally, all investigated amendments improved considerably the uptake of nitrogen, phosphorus, and potassium. Moreover, they increased chlorophyll pigments in leaves and enhanced plant growth parameters upon their application at rates up to 2.5% with superiority for NS-BC versus DP-BC. Liquefied smoke also improved lettuce seed germination and growth, but only up to 0.25% application rate. Our results highlighted the success of the adopted technique for recycling NS and DP wastes and sustaining the environment.

Toxicity reduction of persistent pollutants through the photo-fenton process and radiation/H2O2 using different sources of radiation and neutral pH

The presence of toxic compounds in aquatic bodies is of great concern, and the Fenton, photo-Fenton and radiation/H2O2 processes can be applied in the remediation of these compounds due to their efficiency and advantages. However, these processes need to be investigated to make them more viable and environmentally friendly. Thus, the reduction of toxicity was evaluated, through ecotoxicological tests with Artemia salina and Lactuca sativa, of the compounds 2,4-D, diazepam, nicotine and paracetamol (acetaminophen) by the Fenton, photo-Fenton and radiation/H2O2 process with UVC, UVA and natural solar radiation at neutral pH with low concentrations of Fe2+ and H2O2. The UVC/H2O2 process was efficient in the degradation of nicotine (74%), the photo-Fenton process was more efficient in the degradation of 2,4-D (82%), diazepam (27%) and paracetamol (85%) using solar radiation, UVA and UVC respectively. The toxicity and total organic carbon (TOC) tests showed a reduction in the toxicity of the compounds after treatment, except for diazepam, which was more resistant to the process, leading to a higher mortality of Artemia salinas (92%) and less relative seed germination of Lactuca sativa (40%).

Silver nanoparticle filter for domestic wastewater reuse

AbstractBACKGROUNDUnder scarcity of freshwater, the reuse and low‐cost technological solutions applied to wastewaters seek to reduce contamination to the users and freshwater biota.RESULTSA low‐cost cellulose membrane was doped with silver nanoparticles to filter urban wastewater (UW) from a city in Argentina. The total amount of coliforms and Escherichia coli in the filter decreased by 99.6% and 99.9%, respectively. The leak of silver from the filter was 275 ng L−1, analyzed by square wave anodic stripping voltammetry. Silver nanoparticles tested on HepG2 and A549 mammalian cell lines showed no toxicity in a broad concentration range. Calculation of the organic matter provided by dead bacteria post‐filtration was 347 μg L−1 proteins, 148 μg L−1 nucleic acids, 57 μg L−1 lipids, and 53 μg L−1 polysaccharides, indicating high availability of organic matter. The retention of inorganic salts in the filter was 78.5% ammonia, 6.2% nitrates, 97.6% nitrites, and 19.2% phosphates. In post‐filtered UW, the Lactuca sativa germination test showed early seed germination between 90% and 95% in all the dilutions tested. In the range of 6.25% to 50.0%, filtered UW showed no significant differences in the hypocotyl but the difference was significant in the radicle length (mm) compared to the control made of synthetic media (P < 0.05).CONCLUSIONThe development of a low‐cost filter based on cellulose membranes doped with silver nanoparticles allowed the reuse of wastewater for domestic purposes and garden irrigation. © 2021 Society of Chemical Industry (SCI).

Evaluation of toxic effect of bamboo preservatives on Lactuca sativa germination and growth

Materials such as wood and bamboo in their various applications are subject to degradation by deteriorating organisms like fungi and insects. Chemical treatments are routinely used by bamboo professionals aiming to control this degradation. However, it is usual the dispose of these used solutions on soil and the environmental risks and effects on vegetation of this improper disposal are still unknown. Thus, this study aims to evaluate the phytotoxicity of CCB solutions (compound based on copper, chromium and boron), tetrahydrate sodium octaborate and CB (copper sulfate with boric acid) under different concentrations in the germination and development of lettuce (Lactuca sativa). The pH and electrical conductivity of the prepared solutions were also measured. The results show that the three preservatives are phytotoxic and inhibit root development, even after dilutions of 50 times that used by professionals. Thus, the disposal of these effluents in the soil or water bodies may have negative environmental impacts on vegetation, requiring treatment after use on preservation of the culms or higher dilutions of the effluents before the disposal.

Growth responses and rubisco activity influenced by antibiotics and organic amendments used for stress alleviation in Lactuca sativa

The global increase in the consumption of antibiotics has resulted in contamination of different ecosystems with severe implications on crop productivity. This study investigated the effects of ampicillin and ofloxacin on Lactuca sativa germination upon solution exposure and growth when cultivated in soils treated with three organic amendments (compost, rice husk and vermicompost). Two levels of both antibiotics 5 and 10 mg L−1 (for solution) or mg kg−1 (for soil) were tested in addition to the control. Results indicated that addition of compost significantly (p < 0.05) increased (50%) the root lengths of plant exposed to ampicillin (5 mg L−1). Similarly, vermicompost-amended treatments displayed a 64% increase (p < 0.05) in the shoot length of seedlings under the effect of 5 mg L−1 ofloxacin, depicting a positive synergistic effect between the antibiotics and amendments in the germination test. Nevertheless, the germination percentage remained unaffected in all the treatments. In greenhouse experiment, enhanced plant biomass was observed with the use of rice husk across all the treatment groups. Comparable to the germination test, plants treated with rice husk and compost signaled a higher content of rubisco large subunit (157% and 85%, respectively) and soluble protein (248% and 108%, respectively) post antibiotics application. On the contrary, an antagonistic effect of the rice husk and ofloxacin 5 mg kg−1 was observed on the chlorophyll content, evident by a 37% decrease. Overall, it was observed that the effect of antibiotics on different plant traits vary depending on the antibiotic concentration as well as type of amendment used.

Role of Smoke Stimulatory and Inhibitory Biomolecules in Phytochrome-Regulated Seed Germination of Lactuca sativa.

The biologically active molecules karrikinolide (KAR1) and trimethylbutenolide (TMB) present in wildfire smoke play a key role in regulating seed germination of many plant species. To elucidate the physiological mechanism by which smoke-water (SW), KAR1, and TMB regulate seed germination in photosensitive 'Grand Rapids' lettuce (Lactuca sativa), we investigated levels of the dormancy-inducing hormone abscisic acid (ABA), three auxin catabolites, and cytokinins (26 isoprenoid and four aromatic) in response to these compounds. Activity of the hydrolytic enzymes α-amylase and lipase along with stored food reserves (lipids, carbohydrate, starch, and protein) were also assessed. The smoke compounds precisely regulated ABA and hydrolytic enzymes under all light conditions. ABA levels under red (R) light were not significantly different in seeds treated with TMB or water. However, TMB-treated seeds showed significantly inhibited germination (33%) compared with water controls (100%). KAR1 significantly enhanced total isoprenoid cytokinins under dark conditions in comparison with other treatments; however, there was no significant effect under R light. Enhanced levels of indole-3-aspartic acid (an indicator of high indole-3-acetic acid accumulation, which inhibits lettuce seed germination) and absence of trans-zeatin and trans-zeatin riboside (the most active cytokinins) in TMB-treated seeds might be responsible for reduced germination under R light. Our results demonstrate that SW and KAR1 significantly promote lettuce seed germination by reducing levels of ABA and enhancing the activity of hydrolytic enzymes, which aids in mobilizing stored reserves. However, TMB inhibits germination by enhancing ABA levels and reducing the activity of hydrolytic enzymes.

Clopyralid degradation using solar-photocatalytic/ozone process with olive stone activated carbon

Clopyralid degradation in ultrapure water was investigated by homogeneous ozonation (O3), catalytic ozonation with Olive Stone Activated Carbon (O3/OSAC), under simulated sunlight radiation by photolytic ozonation (O3/Daylight) and photocatalytic ozonation (O3/OSAC/Daylight). The OSAC was characterized by several analytical techniques, such as Nitrogen adsorption desorption at 77 K, Scanning Electron Microscopy (SEM-EDX), determination of pHpzc and X-ray Photoelectron Spectroscopy (XPS). This herbicide exhibited a rapid oxidation rate in the simultaneous presence of ozone, activated carbon and simulated sunlight. The combined process led to a complete removal of clopyralid in less than 30 min. Solar-photocatalytic ozonation was the most efficient process both in terms of clopyralid elimination rate and mineralization. Clopyralid degradation mainly occurs through hydroxyl radical in those systems involving ozone. For comparison purposes, the different processes can be modelled by simple first-order kinetics in clopyralid concentration (rate constants khomo = 0.0159 min−1, homogeneous ozonation; kO3/Daylight = 0.0410 min−1, kO3/OSAC = 0.0705 min−1, kO3/OSAC/Daylight = 0.1433 min−1). 90% of Total Organic Carbon (TOC) removal after 3 h was reached in photocatalytic ozonation (O3/OSAC/Daylight) and photolytic ozonation (O3/Daylight) compared to about 70% using O3/OSAC. Single ozonation just led to 20% TOC reduction under similar operating conditions. Furthermore, small oxygenated organic and inorganic by-products were analyzed by ionic chromatography. As a rule of thumb, TOC removal led to the formation of low weight carboxylic acids, taking place the release of chlorides and nitrates. Finally, toxicity evolution during O3, O3/OSAC, O3/Daylight and O3/OSAC/Daylight were monitored considering phytotoxicity trials of Lactuca Sativa germination. Phytotoxicity assays indicate almost total detoxification after the photocatalytic ozonation treatment.

Metabolomics approach to investigate phytotoxic effects of Wedelia trilobata leaves, litter and soil

Although release and accumulation of plant metabolites from plant into soil can influence allelopathy, little information is known about metabolite changes that occur in leaf, litter and soil. In this study, seed germination bioassay tests and metabolomics analysis were performed to investigate the phytotoxic effects and metabolic variations (measured as buckets) in the ethanolic extracts of leaf, leaf litter and soil of Wedelia trilobata. Increasing the ethanolic extracts concentration of all extracts significantly inhibited Lactuca sativa germination rate (GR), shoot height (SH) and root length (RL). Soil exerted the strongest inhibition but contained the lowest number of buckets relative to those of leaf and leaf litter extracts. An overlap overview on the metabolome revealed a poor bucket overlap and redundancy among the leaf, leaf litter and soil extracts. Canonical correspondence analysis concluded that the SH of L. sativa was more sensitive to leaf litter extract and the leaf extract exerted a strong influence on the GR and RL of L. sativa. Multivariate analysis suggested that the metabolome of the leaf, leaf litter and soil differ substantially. Finally, putative identification using MS/MS data demonstrated various plant metabolites with phytotoxic effects that can contribute to the allelopathy of W. trilobata.

Plant Growth-Promoting Rhizobacteria Improved Salinity Tolerance of Lactuca sativa and Raphanus sativus.

Salinity stress is an important environmental problem that adversely affects crop production by reducing plant growth. The impacts of rhizobacterial strains to alleviate salinity stress on the germination of Lactuca sativa and Raphanus sativus seeds were assessed using different concentrations of NaCl. Plant growth-promoting rhizobacteria (PGPR) strains were also examined to improve the early germination of Chinese cabbage seeds under normal conditions. Lactobacillus sp. and P. putida inoculation showed higher radicle lengths compared with non-inoculated radish (Raphanus sativus) seeds. LAP mix inoculation increased the radicle length of lettuce (Lactuca sativa) seedlings by 2.0 and 0.5 cm at salinity stress of 50 and 100 mM NaCl concentration, respectively. Inoculation by Azotobacter chroococcum significantly increased the plumule and radicle lengths of germinated seeds compared with non-inoculated control. A. chroococcum increased the radicle length relative to the uninoculated seeds by 4.0, 1.0, and 1.5 cm at 50, 100, and 150 mM NaCl concentration, respectively. LAP mix inoculation significantly improved the radicle length in germinated radish seeds by 7.5, 1.3, 1.2, and 0.6 cm under salinity stress of 50, 100, 150, and 200 mM NaCl concentration, respectively. These results of this study showed that PGPR could be helpful to mitigate the salinity stress of different plants at the time of germination.

Volatile organic compounds stimulate plant growing and seed germination of Lactuca sativa

Volatile organic compounds stimulate plant growing and seed germination of Lactuca sativa

Essential Oil of the Brazilian Native Species Hesperozygis ringens: A Potential Alternative to Control Weeds

This study evaluated the allelopathic effect of the Hesperozygis ringens essential oil using dicotyledonous and monocotyledonous seeds which are classified as weeds [Bidens pilosa and Lolium multiflorum], bioindicators [Lactuca sativa and Avena strigosa] and crops [Glycine max and Oryza sativa]. The essential oil from the leaves was extracted and analyzed by gas chromatography coupled to mass spectrometry and gas chromatography with flame ionization detector. The extractive was diluted in ethanol, Tween 20 and water, and then tested at concentrations of 0.25, 0.50, 1.00, 2.50, and 5.00% (v/v). Water and the highest concentration of the solvents were used as control groups. The analyzed variables were germination, emergence velocity index, roots and shoot lengths and total seedlings length. Pulegone was the major essential oil compound representing 82.02% of the composition. Considering dicot seeds, the highest concentration of the extractive completely inhibited the germination of Bidens pilosa without affecting the germination of Lactuca sativa and Glycine max. On monocots, the highest essential oil concentration affected the germination of Lolium multiflorum and Avena strigosa without affecting the Oryza sativa one. The results indicate that the extractive has the potential to control weeds because they were more affected than the crops.

A potential use of vine-shoot wastes: The antioxidant, antifeedant and phytotoxic activities of their aqueous extracts

One of the biggest challenges for wine producing regions is to create alternatives to increase the added value of the large amount of vine-shoot wastes generated. The antioxidant, antifeedant and phytotoxic activities of vine-shoot aqueous extracts obtained by different extraction methods (Conventional Solid-Liquid Extraction, CSLE; Solid-Liquid Dynamic Extraction, SLDE-Naviglio; Microwave Extraction, ME) have been studied. Because of their higher content of phenolic compounds, CSLE and ME extracts showed a higher DPPH radical-scavenging activities compared with SLDE-Naviglio extracts. Significant antifeedant effects against Leptinotarsa decemlineata were observed for CSLE and ME. None of the extracts had phytotoxic effect against Lactuca sativa germination and radicle growth, but SLDE-Naviglio extracts stimulated the radicule elongation. ME extracts were the most active inhibitors of Lolium perenne germination. These results suggest some potential applications of vine-shoot extracts including cosmetics, nutraceuticals or pharmaceuticals linked to their antioxidant effects, or in organic agriculture because of their antifeedant and allelopathic activities.

Fate and risk of atrazine and sulfentrazone to nontarget species at an agriculture site.

The present study evaluated the risk associated with the application and co-occurrence of 2 herbicides, atrazine and sulfentrazone, applied to a 32-ha corn and soybean rotational field. Field concentrations of the compounds were measured in soil, runoff water, and groundwater, with peak mean atrazine and sulfentrazone concentrations found in the soil (144 ng/g dry wt, and 318 ng/g dry wt, respectively). Individual and mixture laboratory bioassays were conducted to determine the effects of atrazine and sulfentrazone on the survival of Daphnia magna and Pimephales promelas, the germination of Lactuca sativa, and the growth of Pseudokirchneriella subcapita and Lemna minor. Pseudokirchneriella subcapita and L. minor were the most susceptible species tested, and the effects on growth of the herbicides in mixtures best fit an independent action model. Risk quotients and margin of safety of 10% (MOS10) values were used to estimate risk and were calculated using runoff water concentrations. The MOS10 values were more sensitive than risk quotients in estimating risk. The MOS10 value for sulfentrazone runoff water concentration effects on P. subcapita was 7.8, and for L. minor was 1.1, with MOS10 values < 1 indicating potential risk. Overall, the environmentally relevant concentrations fell below the effect concentrations; therefore, atrazine and sulfentrazone posed little to no risk to the nontarget species tested. Environ Toxicol Chem 2017;36:1301-1310. © 2016 SETAC.

Assessing the combination of iron sulfate and organic materials as amendment for an arsenic and copper contaminated soil. A chemical and ecotoxicological approach

The efficiency of combining iron sulfate and organic amendments (paper mill sludge, olive mill waste compost and olive tree pruning biochar) for the remediation of an As- and Cu-contaminated soil was evaluated. Changes in As and Cu fractionation and solubility due to the application of the amendments was explored by leachate analysis, single and sequential extractions. Also, the effects on Arrhenatherum elatius growth, germination of Lactuca sativa and toxicity to the bacteria Vibrio fischeri were assessed. The combination of iron sulfate and the organic amendments efficiently reduced As solubility and availability through the formation of amorphous iron oxides, while organic matter did not seem to mobilize As. At the same time, copper fractionation was strongly affected by soil pH and organic matter addition. The soil pH significantly influenced both As and Cu mobility. Within all the amendments tested, FeSO4 in combination with compost showed to be the most suitable treatment for the overall remediation process, as it reduced As and Cu availability andenhanced soil nutrient concentrations and plant growth. In sipte of contradictory trends between chemical analyses and ecotoxicity tests, we can still conclude that the application of organic amendments in combination with reactive iron salts is a suitable approach for the remediation of soils contaminated by Cu and As.

Gibberellins producing Bacillus methylotrophicus KE2 supports plant growth and enhances nutritional metabolites and food values of lettuce

The nutritional quality of green leafy vegetables can be enhanced by application of plant beneficial micro-organisms. The present study was aimed to increase the food values of lettuce leaves by bacterial treatment. We isolated bacterial strain KE2 from Kimchi food and identified as Bacillus methylotrophicus by phylogenetic analysis. The beneficial effect of B. methylotrophicus KE2 on plants was confirmed by increasing the percentage of seed germination of Lactuca sativa L., Cucumis melo L., Glycine max L. and Brassica juncea L. It might be the secretion of array of gibberellins (GA1, GA3, GA7, GA8, GA9, GA12, GA19, GA20, GA24, GA34 and GA53) and indole-acetic acid from B. methylotrophicus KE2. The mechanism of plant growth promotion via their secreted metabolites was confirmed by a significant increase of GA deficient mutant rice plant growth. Moreover, the bacterial association was favor to enhance shoot length, shoot fresh weight and leaf width of lettuce. The higher concentration of protein, amino acids (Asp, Thr, Ser, Glu, Gly, Ala, Leu, Tyr and His), gama-aminobutric acid and fructose was found in bacterial culture (KE2) applied plants. The macro and micro minerals such as K, Mg, Na, P, Fe, Zn and N were also detected as significantly higher quantities in bacteria treated plants than untreated control plants. In addition, the carotenoids and chlorophyll a were also increased in lettuce at bacterial inoculation. The results of this study suggest that B. methylotrophicus KE2 application to soil helps to increase the plant growth and food values of lettuce.