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anxiolytic property of hydro-alcohol extract of lactuca sativa and its effect on behavioral activities of mice.lactuca sativa, belonging to the asteraceae family, is a leafy vegetable known for its medicinal properties. this study aimed to understand the mechanism of lactuca sativa extract with respect to pharmacological action.we investigated the anxiolytic effects of hydro-alcoholic extract of leaves of lactuca sativa on mice. the behavioral tests performed on mice models to assess anti-anxiety properties were: open field test (oft), elevated plus maze test (epm), elevated t maze test, and marble buryi ...201223554792
production and characterization of cyanocobalamin-enriched lettuce (lactuca sativa l.) grown using hydroponics.when lettuces (lactuca sativa l.) grown for 30 days in hydroponic culture were treated with various concentrations of cyanocobalamin for 24 h, its content in their leaves increased significantly from nondetectable to 164.6 ± 74.7 ng/g fresh weight. this finding indicated that consumption of only two or three of these fresh leaves is sufficient to meet the recommended dietary allowance for adults of 2.4 μg/day. analyses using a cobalamin-dependent escherichia coli 215 bioautogram and lc/esi-ms/ms ...201323578327
antibiotic uptake by plants from manure-amended soils.antibiotics are extensively given to livestock to promote growth and reduce diseases. therefore, animal manure often contains antibiotics. once manure is applied to agricultural land to improve soil productivity, crops would be exposed to antibiotics which may persist in soils from a few to several hundred days. the objective of this study was to evaluate the uptake of gentamicin and streptomycin by carrot (daucus carota), lettuce (lactuca sativa) and radish (rhaphanus sativus) from manure-amend ...201323581689
the linear accumulation of atmospheric mercury by vegetable and grass leaves: potential biomonitors for atmospheric mercury pollution.one question in the use of plants as biomonitors for atmospheric mercury (hg) is to confirm the linear relationships of hg concentrations between air and leaves. to explore the origin of hg in the vegetable and grass leaves, open top chambers (otcs) experiment was conducted to study the relationships of hg concentrations between air and leaves of lettuce (lactuca sativa l.), radish (raphanus sativus l.), alfalfa (medicago sativa l.) and ryegrass (lolium perenne l.). the influence of hg in soil o ...201323589268
lactuca spp. seeds as a bioindicator for the toxicity of gezira tannery corporation wastewater.this study was conducted to establish the potential of lettuce (lactuca sativa l. var. buttercrunch) seeds as a bioindicator (bi), or a biological tool for detecting the presence of some toxic materials used in tanning industry and determining their concentrations using the germination percentage as a parameter (indicator). samples of gezira tannery corporation (gtc) wastewater (ww) were collected from both the mouth and the tail of the drainage stream. lettuce seeds (10/petri dish, replicated 3 ...201323631151
growth potential of salmonella and listeria monocytogenes in ready-to-eat lettuce and collard greens packaged under modified atmosphere and in perforated film.this study was aimed at determining the effects of different storage scenarios on the growth potential of salmonella strains and listeria monocytogenes in ready-to-eat (rte) mixes of iceberg and crisp lettuces (lactuca sativa) and collard greens (brassica oleracea). vegetables were submitted to minimal processing, experimentally contaminated to achieve 10(1) and 10(2) cfu/g, packed under modified atmosphere and in perforated film, and submitted to the following storage scenarios: i = 100 % of th ...201323643135
chemical composition of essential oils and in vitro antioxidant activity of fresh and dry leaves crude extracts of medicinal plant of lactuca sativa l. native to sultanate of oman.to isolate and analyse the chemical composition in the essential oils and free radical scavenging activity of different crude extracts from the fresh and dry leaves of vegetable plants of lactuca sativa l. (l. sativa).201323646297
structure-activity relationships of analogs of 3,4,5-trimethylfuran-2(5h)-one with germination inhibitory activities.smoke-derived butenolide compounds have, in recent years, been shown to be important germination signaling molecules, which also affect seedling growth. the butenolide 3,4,5-trimethylfuran-2(5h)-one was previously isolated from plant-derived smoke and was found to significantly reduce the effect on germination by the highly active promotor karrikinolide (kar1, 3-methyl-2h-furo[2,3-c]pyran-2-one), another smoke-derived compound. in this study, 11 analogs of 3,4,5-trimethylfuran-2(5h)-one were syn ...201323648109
genotype variations in cadmium and lead accumulations of leafy lettuce (lactuca sativa l.) and screening for pollution-safe cultivars for food safety.heavy-metals in polluted soils can accumulate in plants and threaten crop safety. to evaluate the risk of heavy-metal pollution in leafy lettuce (lactuca sativa l.), two pot experiments were conducted to investigate cd and pb accumulation and transfer potential in 28 cultivars of lettuce and to screen for low-cd and low-pb accumulative cultivars. in the three treatments, 5.2-fold, 4.8-fold and 4.8-fold differences in the shoot cd concentration were observed between the cultivars with the highest ...201323665926
growth and phenolic compounds of lactuca sativa l. grown in a closed-type plant production system with uv-a, -b, or -c lamp.the production of high-quality crops based on phytochemicals is a strategy for accelerating the practical use of plant factories. previous studies have demonstrated that ultraviolet (uv) light is effective in improving phytochemical production. this study aimed to determine the effect of various uv wavelengths on growth and phenolic compound accumulation in lettuce (lactuca sativa l.) grown in a closed-type plant production system.201423670268
influence of fine process particles enriched with metals and metalloids on lactuca sativa l. leaf fatty acid composition following air and/or soil-plant field exposure.we investigate the effect of both foliar and root uptake of a mixture of metal(loid)s on the fatty acid composition of plant leaves. our objectives are to determine whether both contamination pathways have a similar effect and whether they interact. lactuca sativa l. were exposed to fine process particles enriched with metal(loid)s in an industrial area. data from a first experiment were used to conduct an exploratory statistical analysis which findings were successfully cross-validated by using ...201323694728
phytotoxic activity and metabolism of botrytis cinerea and structure-activity relationships of isocaryolane derivatives.research has been conducted on the biotransformation of (8s,9r)-isocaryolan-9-ol (4a) and (1s,2s,5r,8s)-8-methylene-1,4,4-trimethyltricyclo[6.2.1.0(2,5)]undecan-12-ol (5a) by the fungal phytopathogen botrytis cinerea. the biotransformation of compound 4a yielded compounds 6-9, while the biotransformation of compound 5a yielded compounds 10-13. the activity of compounds 4a and 5a against b. cinerea has been evaluated. (8r,9r)-isocaryolane-8,9-diol (6), a major metabolite of compound 4a, shows act ...201323730968
temporary reduction of radiation does not permanently reduce flavonoid glycosides and phenolic acids in red lettuce.applying transparent daytime screens in greenhouses in cool seasons reduces the amount of energy needed for heating, but also the solar radiation available for crops. this can reduce yield and product quality of leafy vegetables because of constrained photosynthesis and altered biosynthesis. to study this, we cultivated five-week old red leaf lettuce (lactuca sativa l.) for four weeks in growth chambers under a photosynthetic photon flux density (ppfd) of 225 and 410 μmol m(-2) s(-1), respective ...201323735845
human granulocyte colony-stimulating factor (hg-csf) expression in plastids of lactuca sativa.human granulocyte colony-stimulating factor (hg-csf) can serve as valuable biopharmaceutical for research and treatment of the human blood cancer. transplastomic plants have been emerged as a new and high potential candidate for production of recombinant biopharmaceutical proteins in comparison with transgenic plants due to extremely high level expression, biosafety and many other advantages.201323748895
anxiolytic property of lactuca sativa, effect on anxiety behaviour induced by novel food and height.to study anxiolytic property of hydro alchohol extract and to estimate polyphenols present in the extract by hplc.201323768824
irrigation with industrial wastewater activates antioxidant system and osmoprotectant accumulation in lettuce, turnip and tomato plants.we focused on the impact of industrial wastes on the water quality of the el-amia drain in egypt and the effect of irrigation with industrial wastewater on the growth, cell membranes, photosynthetic pigment content, the antioxidant system and selected osmoprotectants (proline, total amino nitrogen and soluble sugars) in three crop plants: turnip, tomato and lettuce. furthermore, the present work focused on the analysis of the heavy metal content and its accumulation in the studied plants. for th ...201323790475
lox-dependent gene expression in transgenic plants obtained via agrobacterium-mediated transformation.lox sites of the cre/lox recombination system from bacteriophage p1 were analyzed for their ability to affect on transgene expression when inserted upstream from a gene coding sequence adjacent to the right border (rb) of t-dna. wild and mutated types of lox sites were tested for their effect upon bar gene expression in plants obtained via agrobacterium-mediated and biolistic transformation methods. lox-mediated expression of bar gene, recognized by resistance of transgenic plants to ppt, occurr ...201323821951
copper, nickel and zinc accumulations in lettuce grown in soil amended with contaminated cattle manure vermicompost after sequential cultivations.the cu, ni and zn accumulations in leaves and roots of lettuce (lactuca sativa l) grown in soil amended with natural and contaminated cattle manure vermicompost were evaluated. the vermicompost residues containing relatively high metal concentrations used in this work were obtained from a previous experiment, in which vermicompost was applied to removing metals from electroplating wastes. sequential lettuce cultivations were conducted in pots containing the residual substrates from the first cul ...201323837328
phytotoxicity of secondary metabolites isolated from flourensia oolepis s.f.blake.the aim of this study was to isolate the active principles of flourensia oolepis s.f.blake (asteraceae), which completely inhibited the germination of raphanus sativus seeds at 10 mg/ml. flavanone pinocembrin and sesquiterpene ilicol, were isolated by bioassay-guided fractionation. they were active both against monocot and dicot seeds. pinocembrin was the most active compound, with an ic50 (germination) value of 0.24, 3.40, 3.28, and 3.55 mm against panicum miliaceum, avena sativa, lactuca sativ ...201323847074
bioactive steroidal saponins from agave offoyana flowers.bioguided studies of flowers of agave offoyana allowed the isolation of five steroidal saponins never described previously, magueyosides a-e (1-5), along with six known steroidal saponins (6-11). the structures of compounds were determined as (25r)-spirost-5-en-2α,3β-diol-12-one 3-o-{β-d-xylopyranosyl-(1→3)-o-β-d-glucopyranosyl-(1→2)-o-[β-d-xylopyranosyl-(1→3)]-o-β-d-glucopyranosyl-(1→4)-o-β-d-galactopyranoside} (1), (25r)-spirost-5-en-2α,3β-diol-12-one 3-o-{β-d-glucopyranosyl-(1→2)-o-[β-d-xylop ...201323859261
uptake of arsenic species by turnip (brassica rapa l.) and lettuce (lactuca sativa l.) treated with roxarsone and its metabolites in chicken manure.roxarsone is an organoarsenic feed additive that can be metabolised to other higher toxic arsenic (as) species in animal manure such as arsenate, arsenite, monomethylarsonic acid, dimethylarsinic acid, 3-amino-4-hydroxyphenylarsonic acid and other unknown as species. the accumulation, transport and distribution of as species in turnip (brassica rapa l.) and lettuce (lactuca sativa l.) amended with roxarsone and its metabolites in chicken manure were investigated. results showed arsenite was the ...201323859781
specific in planta recognition of two gklr proteins of the downy mildew bremia lactucae revealed in a large effector screen in lettuce.breeding lettuce (lactuca sativa) for resistance to the downy mildew pathogen bremia lactucae is mainly achieved by introgression of dominant downy mildew resistance (dm) genes. new bremia races quickly render dm genes ineffective, possibly by mutation of recognized host-translocated effectors or by suppression of effector-triggered immunity. we have previously identified 34 potential rxlr(-like) effector proteins of b. lactucae that were here tested for specific recognition within a collection ...201323883357
genotoxicity of nicotiana tabacum leaves on helix aspersa.tobacco farmers are routinely exposed to complex mixtures of inorganic and organic chemicals present in tobacco leaves. in this study, we examined the genotoxicity of tobacco leaves in the snail helix aspersa as a measure of the risk to human health. dna damage was evaluated using the micronucleus test and the comet assay and the concentration of cytochrome p450 enzymes was estimated. two groups of snails were studied: one fed on tobacco leaves and one fed on lettuce (lactuca sativa l) leaves (c ...201323885210
reversed-phase ultra-high-performance liquid chromatography coupled to electrospray ionization-quadrupole-time-of-flight mass spectrometry as a powerful tool for metabolic profiling of vegetables: lactuca sativa as an example of its application.lettuce (lactuca sativa), a leafy vegetal widely consumed worldwide, fresh cut or minimally processed, constitutes a major dietary source of natural antioxidants and bioactive compounds. in this study, reversed-phase ultra-high-performance liquid chromatography (rp-uhplc) coupled to electrospray ionization-quadrupole-time-of-flight mass spectrometry (esi-qtof-ms) was applied for the comprehensive profiling of polar and semi-polar metabolites from three lettuce cultivars (baby, romaine, and icebe ...201323891214
uptake and accumulation of four ppcp/edcs in two leafy vegetables.many pharmaceutical and personal care products (ppcps) and endocrine-disrupting chemicals (edcs) are present in reclaimed water, leading to concerns of human health risks from the consumption of food crops irrigated with reclaimed water. this study evaluated the potential for plant uptake and accumulation of four commonly occurring ppcp/edcs, i.e., bisphenol a (bpa), diclofenac sodium (dcl), naproxen (npx), and 4-nonylphenol (np), by lettuce (lactuca sativa) and collards (brassica oleracea) in h ...201323911624
a novel substance with allelopathic activity in ginkgo biloba.ginkgo (ginkgo biloba) is one of the oldest living tree species and has been widely used in traditional medicine. leaf extracts of ginkgo, such as the standardized extract egb761, have become one of the best-selling herbal products. however, no bioactive compound directed at plants has been reported in this species. therefore, we investigated possible allelopathic activity and searched for allelopathically active substances in ginkgo leaves. an aqueous methanol leaf extract inhibited the growth ...201323932539
first record of edessa meditabunda (f.) on lettuce in mato grosso state, brazil.we report the first record of the stink bug edessa meditabunda (f.) on lettuce lactuca sativa in the organic vegetable garden "cheiro verde" in tangará da serra, state of mato grosso, brazil (14°37'13″ s, 57°28'46″ w). during september, october, and november 2009, we collected 1,099 adults, 43 nymphs, and 29 egg masses. feeding by this stink bug possibly caused early bolting.201223950014
an intra-specific linkage map of lettuce (lactuca sativa) and genetic analysis of postharvest discolouration traits.minimally processed salad packs often suffer from discolouration on cut leaf edges within a few days after harvest. this limits shelf life of the product and results in high wastage. recombinant inbred lines (rils) derived from a cross between lettuce cvs. saladin and iceberg were shown to be suitable for genetic analysis of postharvest discolouration traits in lettuce. an intra-specific linkage map based on this population was generated to enable genetic analysis. a total of 424 markers were as ...201323959526
identification of thaumatin-like protein and aspartyl protease as new major allergens in lettuce (lactuca sativa).today, about 2-8% of the population of western countries exhibits some type of food allergy whose impact ranges from localized symptoms confined to the oral mucosa to severe anaphylactic reactions. consumed worldwide, lettuce is a compositae family vegetable that can elicit allergic reactions. to date, however, only one lipid transfer protein has been described in allergic reaction to lettuce. the aim of this study was to identify potential new allergens involved in lettuce allergy.201323983075
mineral nutrition and enzymatic adaptation induced by arsenate and arsenite exposure in lettuce plants.arsenate (as(v)) and arsenite (as(iii)) contamination is able to interfere negatively on plant metabolism, promoting a reduction of nutrients uptake and transport and also an increase of reactive oxygen species (ros) generation. however, some plants are considered tolerant against as exposure through the activation of defense mechanisms. therefore, this study aimed to evaluate the effects of different as(v) and as(iii) concentrations (0.0, 6.6, 13.2, 26.4 and 52.8 μmol l(-1)), on mineral nutrien ...201324007815
toxicological evaluation of vegetable oils and biodiesel in soil during the biodegradation process.vegetable oils and their derivatives, like biodiesel, are used extensively throughout the world, thus posing an environmental risk when disposed. toxicity testing using test organisms shows how these residues affect ecosystems. toxicity tests using earthworms (eisenia foetida) are widespread because they are a practical resource for analyzing terrestrial organisms. for phytotoxicological analysis, we used seeds of arugula (eruca sativa) and lettuce (lactuca sativa) to analyze the germination of ...201224031989
fine mapping quantitative resistances to downy mildew in lettuce revealed multiple sub-qtls with plant stage dependent effects reducing or even promoting the infection.three regions with quantitative resistance to downy mildew of non-host and wild lettuce species, lactuca saligna , disintegrate into seventeen sub-qtls with plant-stage-dependent effects, reducing or even promoting the infection. previous studies on the genetic dissection of the complete resistance of wild lettuce, lactuca saligna, to downy mildew revealed 15 introgression regions that conferred plant stage dependent quantitative resistances (qtls). three backcross inbred lines (bils), carrying ...201324037018
identification of three fungi newly intercepted from importing plants in korea.three fungi newly intercepted from importing plants were identified in 2004. they were ascochyta chrysanthemi on lactuca sativa from china, a. spinaciicola on spinacia oleracea from denmark, and leptosphaerulina australis on brassica oleracea var. capitata from china. the characters of these fungi were described and illustrated.200524049509
substituent effects of cis-cinnamic acid analogues as plant growh inhibitors.1-o-cis-cinnamoyl-β-d-glucopyranose is one of the most potent allelochemicals that has been isolated from spiraea thunbergii sieb by hiradate et al. it derives its strong inhibitory activity from cis-cinnamic acid (cis-ca), which is crucial for phytotoxicity. by preparing and assaying a series of cis-ca analogues, it was previously found that the key features of cis-ca for lettuce root growth inhibition are a phenyl ring, cis-configuration of the alkene moiety, and carboxylic acid. on the basis ...201324070619
quantitative trait loci associated with tipburn, heat stress-induced physiological disorders, and maturity traits in crisphead lettuce.crisphead lettuce (lactuca sativa l.) crops exhibit several economically important, physiological disorders when grown in high temperature conditions. these include tipburn, rib discoloration, premature bolting, ribbiness, and internal rib cracking. we evaluated seven physiological disorders and three agronomic traits segregating in a recombinant inbred line (ril) population consisting of 152 f7 rils derived from an intra-specific cross between two crisphead cultivars, l. sativa cv. emperor x l. ...201324078012
chemical compositions, phytotoxicity, and biological activities of acorus calamus essential oils from nepal.four essential oils from the leaf (p23) and rhizomes (p19, p22, p24) of acorus calamus l., collected from various parts of nepal, were obtained by hydrodistillation and analyzed by gc-ms. from a total of 61 peaks, 57 compounds were identified among the four essential oils accounting for 94.3%, 96.2%, 97.6%, and 94.1% of the oils, respectively. all of the essential oils were dominated by (z)-asarone (78.1%-86.9%). the essential oils also contained (e)-asarone (1.9%-9.9%) and small amounts of gamm ...201324079199
use of hairy roots extracts for 2,4-dcp removal and toxicity evaluation by lactuca sativa test.2,4-dichlorophenol (2,4-dcp) is widely distributed in wastewaters discharged from several industries, and it is considered as a priority pollutant due to its high toxicity. in this study, the use of different peroxidase extracts for 2,4-dcp removal from aqueous solutions was investigated. tobacco hairy roots (hrs), wild-type (wt), and double-transgenic (dt) for tomato basic peroxidases (tpx1 and tpx2) were used to obtain different peroxidase extracts: total peroxidases (tpx), soluble peroxidases ...201424085515
identification of qtls conferring resistance to downy mildew in legacy cultivars of lettuce.many cultivars of lettuce (lactuca sativa l.), the most popular leafy vegetable, are susceptible to downy mildew disease caused by bremia lactucae. cultivars iceberg and grand rapids that were released in the 18th and 19th centuries, respectively, have high levels of quantitative resistance to downy mildew. we developed a population of recombinant inbred lines (rils) originating from a cross between these two legacy cultivars, constructed a linkage map, and identified two qtls for resistance on ...201324096732
[analysis of the mineral elements of lactuca sativa under the condition of different spectral components].mineral elements absorption and content of lactuca sativa under different spectral component conditions were studied by icp-aes technology. the results showed that: (1) for lactuca sativa, the average proportion for ca : mg : k : na : p was 5.5 : 2.5 : 2.3 : 1.5 : 1.0, the average proportion for fe : mn : zn : cu : b was 25.9 : 5.9 : 2.8 : 1.1 : 1.0; (2) the absorptions for k, p, ca, mg and b are the largest under the led treatment r/b = 1 : 2.75, red light from fluorescent lamps and led can bot ...201324159877
physiological, phytochemical and structural changes of multi-leaf lettuce caused by salt stress.environmental stress due to salt has been described to enhance lettuce processability, shelf life and consumer acceptability. moderate salinity causes altered leaf carotenoid, lignin, phenolic and flavonol levels without noticeable changes in the green colour and morphology of lettuce. the aim of this study was to understand the improvements in processability, due to salt stress, related to textural properties and structural characteristics.201424170602
[effects of applying pig manure on lettuce yield and nitrate content and soil nutrients].a pot experiment with two representative soils (purple soil and yellow soil) in southwest china was conducted to study the effects of applying pig manure on the lettuce (lactuca sativa l. var. capitata l. ) yield and nitrate content and the soil nutrients. applying pig manure increased the lettuce yield significantly, and the increment was higher for yellow soil than for purple soil. the nitrate and total nitrogen, phosphorus, and potassium contents in lettuce plants were closely related to soil ...201324175524
design and synthesis of conformationally constrained analogues of cis-cinnamic acid and evaluation of their plant growth inhibitory activity.1-o-cis-cinnamoyl-β-d-glucopyranose is known to be one of the most potent allelochemical candidates and was isolated from spiraea thunbergii sieb by hiradate et al. (2004), who suggested that it derived its strong inhibitory activity from cis-cinnamic acid, which is crucial for phytotoxicity. in this study, key structural features and substituent effects of cis-cinnamic acid (cis-ca) on lettuce root growth inhibition was investigated. these structure-activity relationship studies indicated the i ...201324176527
genetic mapping of turnip mosaic virus resistance in lactuca sativa.presence of the dominant tu gene in lactuca sativa is sufficient to confer resistance to infection by turnip mosaic virus (tumv). in order to obtain an immunological assay for the presence of tumv in inoculated plants, the tumv coat protein (cp) gene was cloned by amplification of a cdna corresponding to the viral genome using degenerate primers designed from conserved potyvirus cp sequences. the tumv cp was overexpressed in escherichia coli, and polyclonal antibodies were produced. to locate tu ...199424177934
potential allelopathic indole diketopiperazines produced by the plant endophytic aspergillus fumigatus using the one strain-many compounds method.on the basis of the osmac (one strain-many compounds) strategy, 14 indole diketopiperazine (dkp) alkaloids, including spirotryprostatins (1-3), tryprostatins (4-6), and cyclotryprostatins (7-14), were isolated from the endophyte aspergillus fumigatus associated with melia azedarach l. their structures were identified by nuclear magnetic resonance and electrospray ionization mass spectrometry data. all the indole dkps were evaluated for plant growth regulation using the lettuce (lactuca sativa) s ...201324188331
microwave-enhanced uv/h2o2 degradation of an azo dye (tartrazine): optimization, colour removal, mineralization and ecotoxicity.this study optimizes two factors, ph and initial [h2o2], in the ultraviolet (uv)/h2o2/microwave (mw) process through experimental design and assesses the effect of mws on the colour removal of an azo-dye (tartrazine) solution that was favoured by an acidic ph. the estimated optimal conditions were: initial [h2o2] = 2.0 mmol l(-1) and ph = 2.6, at 30 +/- 2 degrees c. we obtained colour removals of approximately 92% in 24 min of irradiation (edl, 244.2 w), following zero order kinetics: k = (3.9 + ...201324191458
interactions of uptake of malate and nitrate into isolated vacuoles from lettuce leaves.vacuoles were isolated from leaves of two lettuce (lactuca sativa l.) genotypes that differed significantly in their nitrate accumulation. the rate of nitrate uptake into the vacuoles did not differ between the genotypes, but the malate-uptake rate did. fitting a michaelis-menten equation, with or without the addition of a linear term, showed that the rates of malate and nitrate uptake can be best described by saturation kinetics for both genotypes. malate transport across the tonoplast showed a ...199124193527
complementary analysis of freeze-dried and frozen-hydrated plant tissue by electron-probe x-ray microanalysis: spectral resolution and analysis of calcium.automated methods of peak determination including peak location, background determination and peak deconvolution are presented. special attention is given to the problem of severely overlapped peaks, such as the primary calcium peak (caka) and the secondary potassium peak (kkβ). a method, based on the principle of electronic transitional probabilities, is presented for estimating ca in the presence of a high background of k, and limitations of resolution are discussed. minimally detectable conce ...199124194149
the nutritional status of the apical meristem of lactuca sativa as affected by nacl salinization: an electron-probe microanalytic study.a volume of tissue of lettuce (lactuca sativa l.) plants extending 2 mm basipetally from the apical meristem and including leaf primordia and young expanding leaves was surveyed using electron-probe microanalysis (epma) on both frozen-hydrated and freeze-dried samples. this analysis was carried out either 2 or 5 d following nacl salinization of the medium from the 10 mol · m(--3) control level up to 80 mol · m(--3). the objective was the investigation of possible changes in the nutritional statu ...199124194150
influence of fertilizer and sewage sludge compost on yield and heavy metal accumulation by lettuce grown in urban soils.previous research has demonstrated that many urban soils are enriched in pb, cd and zn. culture of vegetable crops in these soils could allow transfer of potentially toxic metals to foods. 'tanya' lettuce (lactuca sativa l.) was grown in pots of five urban garden soils and one control agricultural soil to assess the effect of urban-soil metal enrichment, and the effect of soil amendments, on heavy metal uptake by garden vegetables. the amendments included npk fertilizer, limestone, ca(h2po4)2, a ...199624194408
qtl mapping of leafy heads by genome resequencing in the ril population of brassica rapa.leaf heads of cabbage (brassica oleracea), chinese cabbage (b. rapa), and lettuce (lactuca sativa) are important vegetables that supply mineral nutrients, crude fiber and vitamins in the human diet. head size, head shape, head weight, and heading time contribute to yield and quality. in an attempt to investigate genetic basis of leafy head in chinese cabbage (b. rapa), we took advantage of recent technical advances of genome resequencing to perform quantitative trait locus (qtl) mapping using 15 ...201324204591
uptake of perfluoroalkyl acids into edible crops via land applied biosolids: field and greenhouse studies.the presence of perfluoroalkyl acids (pfaas) in biosolids destined for use in agriculture has raised concerns about their potential to enter the terrestrial food chain via bioaccumulation in edible plants. uptake of pfaas by greenhouse lettuce ( lactuca sativa ) and tomato ( lycopersicon lycopersicum ) grown in an industrially impacted biosolids-amended soil, a municipal biosolids-amended soil, and a control soil was measured. bioaccumulation factors (bafs) were calculated for the edible portion ...201324206563
chloroplast gene expression in lettuce grown under different irradiances.chloroplast dna sequences have been used as hybridisation probes to measure the levels of rna transcripts present in low- and high-light-grown lettuce (lactuca sativa l.) plants. the transcript levels for rbc l, psa a, psb a and rdna are not different between these two light regimes. in contrast, transcript levels for atp be and pet bd are increased in high-light as a proportion of the chloroplast rna. three days after transfer from low-light into high-light, increased transcript levels were fou ...198924212551
comparative biochemical and immunological studies of the glycine betaine synthesis pathway in diverse families of dicotyledons.members of the chenopodiaceae can accumulate high levels (>100 μmol·(g dw)(-1)) of glycine betaine (betaine) in leaves when salinized. chenopodiaceae synthesize betaine by a two-step oxidation of choline (choline→betaine aldehyde→ betaine), with the second step catalyzed by betaine aldehyde dehydrogenase (badh, ec 1.2.1.8). high betaine levels have also been reported in leaves of species from several distantly-related families of dicotyledons, raising the question of whether the same betaine-syn ...198924212901
interspecific somatic hybridization between lettuce (lactuca sativa) and wild species l. virosa.somatic hybrids between cultivated lettuce (lactuca sativa) and a wild species l. virosa were produced by protoplast electrofusion. hybrid selection was based on inactivation of l. sativa with 20mm iodoacetamide for 15 min, and the inability of l. virosa protoplasts to divide in the culture conditions used. protoplasts were cultured in agarose beads in a revised ms media. in all 71 calli were formed and 21 of them differentiated shoots on ls medium containing 0.1mg/l naa and 0.2mg/l ba. most reg ...199124220705
induced expression of a chimeric gene construct in transgenic lettuce plants using tobacco pathogenesis-related protein gene promoter region.the expression of a stress- and salicylic acidinducible protein gene from tobacco, pr1a protein gene, was determined after its introduction to lettuce (lactuca sativa l.) plants. the 5' flanking 2.4 kb fragment from pr1a gene was joined to the bacterial β -glucuronidase (gus) gene (pr-gus) and introduced into lettuce cotyledons by agrobacterium-mediated gene transfer using a binary vector containing a kanamycin-resistance gene as a selectable marker. as a control with constitutive expression, th ...199024226367
β-mannoside mannohydrolase and the mobilization of the endosperm cell wall of lettuce seeds, cv. grand rapids.mobilization of the endosperm cell-wall reserves of lactuca sativa l. cv. grand rapids requires endo-β-mannanase and α-galactosidase activity. a third enzyme, β-mannoside mannohydrolase (ec 3.2.1.25) is also involved. we have determined the optimum extraction and assay conditions for this enzyme, which is soluble only in high-salt (1 m nacl) buffer. it is located exclusively within the cotyledons, in association with a cellulosic cell-wall fraction. its substrates are the products of endosperm c ...198624232644
brpspl9 (brassica rapa ssp. pekinensis spl9) controls the earliness of heading time in chinese cabbage.the leafy heads of cabbage (brassica oleracea), chinese cabbage (brassica rapa ssp. pekinensis), brussels sprouts (b. oleracea ssp. gemmifera) and lettuce (lactuca sativa) comprise extremely incurved leaves that are edible vegetable products. the heading time is important for high quality and yield of these crops. here, we report that brpspl9-2 (b. rapa ssp. pekinensis squamosa promoter binding-like 9-2), a target gene of microrna brp-mir156, controls the heading time of chinese cabbage. quantit ...201424237584
comparison of restriction endonucleases and sources of probes for their efficiency in detecting restriction fragment length polymorphisms in lettuce (lactuca sativa l.).as a first step in developing a detailed genetic map of lettuce (lactuca sativa l.), 156 cdna and 123 genomic dna clones of lettuce were compared for their efficiency to detect restriction fragment length polymorphism (rflp) between four lines of lettuce. polymorphism was detected 2.5 times more frequently with cdna probes than random genomic probes. less polymorphism was detected with cdna clones homologous to single copy than with cdna clones homologous to multiple copy dna sequences. a lower ...198724240222
phloem sap collection from lettuce (lactuca sativa l.): methodology and yield.three methods to collect phloem sap on different lettuce lines were optimized and are described in detail. the success ratio for stylectomy of aphids was over 80% through the combination of a specially designed setup and electrical penetration graphs to monitor phloem sap ingestion. for unknown reasons on some lettuce lines stylets never showed sustained exudation. there were clear differences in stylet exudation between two aphid species on the same lettuce line. honeydew collection in hexadeca ...199424241985
phloem sap collection from lettuce (lactuca sativa l.): chemical comparison among collection methods.the chemical composition of phloem sap from lettuce, collected by three different methods, was compared. phloem sap from stylectomy samples contained sucrose and 14 amino acids. honeydew and edta chelation samples showed considerable breakdown of sucrose into fructose and glucose, several additional amino acids, and large differences in relative concentrations of amino acids, when compared to stylectomy samples. honeydew contained considerable amounts of other oligosaccharides, and few proteins ...199424241986
allelopathy of oats. i. assessment of allelopathic potential of extract of oat shoots and identification of an allelochemical.the allelopathic potential of oat (avena sativa l.) extracts was investigated under laboratory conditions. the ethyl ether-, acetone-, and water-soluble fractions obtained from the extract of oat shoots inhibited the germination and growth of roots and hypocotyls of lettuce (lactuca sativa l.). the inhibitory activity of the water-soluble fraction was maximum, followed by that of ethyl ether-soluble and acetone-soluble fraction. an active principle of the water-soluble fraction was isolated and ...199424242056
allelopathy of oats. ii. allelochemical effect ofl-tryptophan and its concentration in oat root exudates.l-tryptophan caused growth inhibition of roots and hypocotyls (or coleoptiles) of cockscomb (amaranthus caudatus l.), lettuce (lactuca sativa l.), cress (lepidium sativum l.), timothy (phleum pratense l.), rice (oryza sativa l.), wheat (triticum aestivum l.), and oat (avena sativa l.), increasing the dose ofl-tryptophan increased the inhibition. the concentrations for 50% inhibition of the root growth were 0.14, 0.15, 0.21, 0.79, 0.95, 1.7, and 2.4 mm for cockscomb, cress, lettuce, timothy, rice ...199424242057
transformation of lettuce (lactuca sativa) mediated by agrobacterium tumefaciens.lactuca sativa can be routinely transformed using ti plasmids of agrobacterium tumefaciens containing a chimeric kanamycin resistance gene (nos.nptii.nos). critical experimental variables were plant genotype, bacterial concentration, presence of a nurse culture and timing of transfers between tissue culture media. transformation was confirmed by the ability to callus and root in the presence of kanamycin, nopaline production, and by hybridization in southern blots. transformation has been achiev ...198724248927
cell-programmed death induced by walnut husk washing waters in three horticultural crops.walnut husk washing waters (whww), a by-product of walnut production, are indiscriminately used for irrigation without preliminary risk assessment. basing on previous in vitro results on the toxicity of this by-product, we have followed the morphophysiological development of zea mays, lactuca sativa cv. gentilina and l. sativa cv. canasta under diluted and undiluted whww irrigation. significant development alterations have been observed in root and shoot elongations for all crops as well as in t ...201424249681
spectrophotometric determination of cu(2+) and monitoring of hg(2+) and ni(2+) in some iranian vegetables using 6-(2-naphthyl)-2, 3-dihydro-as-triazine-3-thione.recently, 6-(2-naphthyl)-2, 3-dihydro-as-triazine-3-thione (ndtt) was synthesized in laboratory and used successfully for the spectrophotometric determination of nanogram levels of cu(2+) in aqueous solution. this reagent forms a specific red complex with cu(2+) ions after the extraction by chloroform at alkaline ph. the absorption of the complex in the uv region (313 nm) is about 8 times as strong as in the visible one (510 nm). mercury and nickel ions form yellow complexes with ndtt under the ...201324250566
potentiating effects of lactuca sativa on pentobarbital-induced sleep.traditionally, lactuca sativa (lettuce) has been recommended for its hypnotic property. the present study was planned to investigate sleep-prolonging effect of this plant. the hydro-alcoholic extract (hae) of lettuce and its water fraction (wf), ethyl acetate fraction (eaf), and n-butanol fraction (nbf) were administrated (ip) to mice 30 min before the pentobarbital injection. moreover, both in-vivo and in-vitro toxicity of the extracts were determined. the quality of hae and nbf was also evalua ...201324250615
field study on the accumulation of trace elements by vegetables produced in the vicinity of abandoned pyrite mines.to evaluate the accumulation of trace elements (te) by vegetables produced in the vicinity of abandoned pyrite mines, eighteen different small farms were selected near three mines from the portuguese sector of the iberian pyrite belt (são domingos, aljustrel and lousal). total and bioavailable as, cu, pb, and zn concentrations were analyzed in the soils, and the same te were analyzed in three different vegetables, lettuce (lactuca sativa), coriander (coriandrum sativum), and cabbage (brassica ol ...201424252198
linkage analysis of genes for resistance to downy mildew (bremia lactucae) in lettuce (lactuca sativa).the genetics of specific resistance was studied in f2 populations which segregated for either one or two resistance genes. the resistance factors 1, 11 and 14 which had not previously been characterized genetically segregated as single dominant genes (dm). resistance was determined by three linkage groups; r 1/14, 2, 3, and 6 in the first, r 5/8, and 10 in the second and r 4, 7 and 11 in the third. cultivars of lettuce commonly used in the differential series to detect virulence to r3 and r10, w ...198524253062
pathogenic variation and sexual reproduction in swedish populations of bremia lactucae.the host-pathogen interaction between lettuce (lactuca sativa) and downy mildew (bremia lactucae) is mainly differential and the resistance so far utilized in the host is vertical. as in many other obligate parasites, the introduction of cultivars with new vertical resistance has exerted a strong selection pressure on the pathogen resulting in significant changes in virulence frequencies and in the establishment of races with new combinations of virulence. genetic diversity in pathogen populatio ...198524253122
changes in germination and respiratory potential of embryos of dormant grand rapids lettuce seeds during long-term imbibed storage, and related changes in the endosperm.grand rapids lettuce (lactuca sativa l.) seeds were stored in an imbibed state for up to two years. embryos dissected from stored seeds showed a progressive loss with time in their ability to germinate on polyethylene glycol (peg) solutions. little germination of dissected embryos from one-month imbibed seeds occurred on-6 bar peg but only after four months of storage did the dissected embryos fail to germinate on-4 bar peg. after two years storage 30% of dissected embryos still were able to ger ...198424253946
comparative toxicity of six test chemicals to lettuce using two root elongation test methods.lettuce (lactuca sativa l., cv buttercrunch) was used to evaluate and compare the results from two different root elongation phytotoxicity test methods with the same six test substances. seeds were either germinated in the dark on an inclined filter paper substrate with one end immersed in test solution or germinated in 0.1 strength nutrient solution with a 16 hr light period in a glass bulb mixed and aerated with compressed air. sodium fluoride, monosodium methanearsonate and monuron reduced le ...198624254736
improving water use efficiency of lettuce (lactuca sativa l.) using phosphorous fertilizers.a greenhouse pot experiment was conducted to evaluate the effect of phosphorous (p) fertilizers application to an alkaline calcareous soil on the water use efficiency (wue) of lettuce cultivar "robinson" of iceberg type. head fresh and dry weights, total water applied and wue were affected significantly by the p fertilizer type and rate. p fertilizers addition induced a significant enhancement in the wue and fresh and dry weights of the crop. a local phosphate rock (pr) applied directly was foun ...201324255857
long-term storage of dormant grand rapids lettuce seeds in the imbibed state: physiological and metabolic changes.grand rapids lettuce (lactuca sativa l.) seeds retained their viability for up to ten months when maintained in the fully imbibed state on moist filter paper at 25°c in darkness. the ability of red light (r) to promote their germination was essentially lost within one week from the start of imbibition; sensitivity to gibberellic acid was retained for two weeks longer. seeds which did not respond to either treatment had entered the state of secondary dormancy (skotodormancy). this could be reliev ...198324258141
effect of light and temperature on the germination of lettuce seeds.a short period (15-30 min) at 30° c promotes germination of seeds of lactuca sativa l. cv. repolhuda in darkness. far-red light reverses this stimulation, and the escape curves for phytochrome and high-temperature action are quite similar, indicating that the two factors act at a common point in the chain of events leading to germination. it is suggested that high temperature acts by decreasing the threshold of the active, far-red absorbing, form of phytochrome (pfr) needed to promote germinatio ...198424258424
effect of abiotic elicitation on main health-promoting compounds, antioxidant activity and commercial quality of butter lettuce (lactuca sativa l.).the study presents changes in the phytochemical levels, antiradical activity and quality of lettuce caused by different chemical elicitors: arachidonic acid (aa), jasmonic acid (ja), and abscisic acid (aba). the application of 1 μm and 100 μm ja induced an increase in the concentration of phenolic compounds, including flavonoids and phenolic acids. flavonoid levels were also increased after treatment with 100 μm aa and aba. some of the elicitor concentrations used also caused an increase in the ...201424262554
a role for α-galactosidase in the degradation of the endosperm cell walls of lettuce seeds, cv. grand rapids.isolated endosperms of grand rapids lettuce (lactuca sativa l.) seeds undergo extensive cell-wall degradation and sugars are released into the surrounding incubation medium. one sugar so released is galactose. α-galactosidase (ec 3.2.122) is present at the same level in both dry and imbibed isolated endosperms and is responsible for the release of galactose. however, this enzyme does not act upon the native endosperm cell wall, but requires first its partial hydrolysis and the production of olig ...198324264159
inhibition of seed germination by quinolizidine alkaloids : aspects of allelopathy in lupinus albus l.germination of lactuca sativa l. was inhibited by mixtures of quinolizidine alkaloids. the alkaloid esters resulted in the strongest inhibition: 6 mm 13-tigloyloxylupanine inhibited germination by 100%, whereas the other lupin alkaloids, such as lupanine and sparteine, gave a 45 and 20% inhibition, respectively. seedlings of lupinus albus l., which are not affected by quinolizidine alkaloids, excrete lupanine and 13-tigloyloxylupanine into the surrounding medium by their roots. it is assumed tha ...198324264757
foliar exposure of the crop lactuca sativa to silver nanoparticles: evidence for internalization and changes in ag speciation.the impact of engineered nanomaterials on plants, which act as a major point of entry of contaminants into trophic chains, is little documented. the foliar pathway is even less known than the soil-root pathway. however, significant inputs of nanoparticles (nps) on plant foliage may be expected due to deposition of atmospheric particles or application of np-containing pesticides. the uptake of ag-nps in the crop species lactuca sativa after foliar exposure and their possible biotransformation and ...201424275476
the effects of colchicine and gibberellic acid on growth and microtubules in excised lettuce hypocotyls.the effect of colchicine on growth and microtubules in h2o-and gibberellic acid (ga3)-treated hypocotyls of lettuce (lactuca sativa l. cv. arctic) was examined. hypocotyls of seedlings from γ-irradiated as well as non-irradiated seedlings were used in order to establish that the drug was affecting cell elongation and not cell division. although colchicine inhibited elongation of ga3-treated hypocotyl sections at concentrations as low as 1 μm, it did not affect the growth of sections. rather, col ...198224276062
evidence for a race-specific resistance factor in some lettuce (lactuca sativa l.) cultivars previously considered to be universally susceptible to bremia lactucae regel.previously undetected race-specific resistance to bremia lactucae (downy mildew) was located in many lettuce cultivars hitherto considered to be universally susceptible to this disease. this resistance factor(s) may also be widely distributed in other cultivars known to carry combinations of already recognised factors r1 to r11. specific virulence to match this resistance is almost invariably present in pathogen collections. this situation may be either a relic of the evolutionary history of the ...198124276692
construction of transplastomic lettuce (lactuca sativa) dominantly producing astaxanthin fatty acid esters and detailed chemical analysis of generated carotenoids.the plastid genome of lettuce (lactuca sativa l.) cv. berkeley was site-specifically modified with the addition of three transgenes, which encoded β,β-carotenoid 3,3'-hydroxylase (crtz) and β,β-carotenoid 4,4'-ketolase (4,4'-oxygenase; crtw) from a marine bacterium brevundimonas sp. strain sd212, and isopentenyl diphosphate isomerase from a marine bacterium paracoccus sp. strain n81106. constructed transplastomic lettuce plants were able to grow on soil at a growth rate similar to that of non-tr ...201424287848
red-light- and gibberellic-acid-enhanced α-galactosidase activity in germinating lettuce seeds, cv. grand rapids : control by the axis.dry lettuce (lactuca sativa l.) "seeds" (achenes) contain α-galactosidase (ec 3.2.122) at a level which is maintained in the imbibed dormant state in darkness. both red light (r) and gibberellic acid promote an increase in enzyme activity several hours prior to the completion of germination. germination and enzyme activity are not essentially linked, however, for the latter can increase while the former is inhibited. α-galactosidase activity increases within the cotyledons and the endosperm foll ...198124301117
short-term kinetics of elongation growth of gibberellin-responsive lettuce hypocotyl sections.the short-term kinetics of growth of the excised lettuce (lactuca sativa l.) hypocotyl were characterized with respect to the effects of gibberellic acid (ga3), indole-3-acetic acid (iaa), kcl and ph. a hall-device-based, miniaturized, linear displacement transducer was developed to measure the growth of 2-mm hypocotyl sections with 1-μm resolution. following treatment with ga3, a lag time of less than 10 min was typically followed by an increase in growth rate with two acceleration phases, reac ...198124301118
calcium and gibberellin-induced elongation of lettuce hypocotyl sections.the relationship between calcium ions and gibberellic acid (ga3)-induced growth in the excised hypocotyl of lettuce (lactuca sativa l.) was investigated. the short-term kinetics of growth responses were measured using a linear displacement transducer. test solutions were added either as drops to the filter paper on which the hypocotyl stood ("non-flow-past") or by switching solution flowing past the base of hypocotyl ("flow-past"), resulting in differences in growth behavior. drops of cacl2 adde ...198124301119
role of benzoxazinones in allelopathy by rye (secale cereale l.).two phytotoxic compounds [2,4-dihydroxy-1,4(2h)-benzoxazin-3-one (diboa) and 2(3h)-benzoxazolinone (boa)] were previously isolated and identified in 35-day-old greenhouse-grown rye shoot tissue. both compounds were also detected by tlc in greenhouse-grown root and fieldgrown shoot tissue. the concentration of diboa varied in the tissues, with the greatest quantity detected in greenhouse-grown shoots. diboa and boa were compared with β-phenyllactic acid (pla) and β-hydroxybutyric acid (hba) for a ...198724302054
growth physics and water relations of red-light-induced germination in lettuce seeds : v. promotion of elengation in the embryonic axes by gibberellins and phytochrome.red light (r) and gibberellins (ga) each induce a water potential decrease in the axes of lettuce (lactuca sativa l.) embryos resulting in germination of intact "seeds" (achenes) or an increase in growth of the axes of isolated embryos. the fruit coat and endosperm are a substantial barrier to the penetration of exogeneous ga. isolated embryos take up 35 times as much [(3)h]ga1 as the embryos of intact seeds and respond to less than 1·10(-10) m ga3 or ga4+7. we calculated that only 1·10(-8) m of ...198124302380
withanolides with phytotoxic activity from two species of the genus salpichroa: s. origanifolia and s. tristis var. lehmannii.seven new withanolides, salpichrolides o-u (1-7), the known 2,3-dihydrosalpichrolide b (9), a substance not previously isolated from a natural source, and three known compounds, salpichrolide d (8), salpichrolide a (10), and salpichrolide c (11), were isolated and characterized from the aerial parts of salpichroa origanifolia and s. tristis var. lehmannii. compounds 1-4 and 8 have an oxygenated d ring, while compounds 5-7 and 9-11 possess a six-membered aromatic d ring. the structures of the iso ...201324303781
occurrence of the carotenoid lactucaxanthin in higher plant lhc ii.the pigment composition of the light-harvesting complexes of photosystem ii (lhc ii) has been determined for lettuce (lactuca sativa). in common with other members of the composite, the photosynthetic tissues of this species may contain large amounts of the carotenoid lactucaxanthin (ε, ε-carotene-3,3'-diol) in addition to their normal compliment of carotenoids. the occurrence and distribution of lactucaxanthin in lhc ii has been examined using isoelectric focusing of bby particles followed by r ...199524306850
interaction of [(3)h]gibberellin a 1 with a sub-cellular fraction from lettuce (lactuca sativa l.) hypocotyls : the relationship between growth and incorporation.the relationship between elongation growth and the incorporation of [(3)h]gibberellin a1 ([(3)h]ga1) into a 2,000g pelletable (2kp) fraction from lettuce (lactuca sativa l., cv. arctic) hypocotyl sections has been examined. sections were loaded with incremental amounts of ga1 under conditions where growth was arrested (5° c) or permitted (30° c) and, after 16 h, all were transferred to a ga-free medium at 30° c. growth and 2kp radioactivity were measured at this point and after a further 24 h in ...198024310192
interaction of [(3)h]gibberellin a 1 with a sub-cellular fraction from lettuce (lactuca sativa l.) hypocotyls : requirement for protein synthesis.the relationship between protein synthesis and the incorporation of [(3)h]gibberellin a1 ([(3)h]ga1) into a 2,000xg pelletable (2kp) fraction from lettuce (lactuca sativa l.) hypocotyl sections has been investigated. concentrations of d-2-(4-methyl-2,6-dinitroanilino)-n-methylpropionamide (mdmp) between 10(-7) m and 10(-4) m caused increasing inhibition of growth, 2kp labelling and incorporation of [(14)c]leucine into soluble protein. growth and 2kp radioactivity were highly correlated (r=0.996) ...197924311043
membrane barriers and mehler-peroxidase reaction limit the ascorbate available for violaxanthin de-epoxidase activity in intact chloroplasts.the presence of an acidic lumen and the xanthophylls, zeaxanthin and antheraxanthin, are minimal requirements for induction of non-radiative dissipation of energy in the pigment bed of photosystem ii. we recently reported that ascorbate, which is required for formation for these xanthophylls, also can mediate the needed lumen acidity through the mehler-peroxidase reaction [neubauer and yamamoto (1992) plant physiol 99: 1354-1361]. it is demonstrated that in non-co2-fixing intact chloroplasts and ...199424311066
the influence of plant growth regulators on the growth of the embryonic axes of red- and far-red-treated lettuce seeds.the influence of several plant growth regulators on the growth of the embryonic axes from red- and far-red-(r- and fr-)treated lettuce (lactuca sativa l., cv. grand rapids) seeds was examined; as shown previously, the water potential of the axes from r-treated seeds has been lowered by 3.5-5.6 bars compared to that in axes from fr-treated ones. kinetin and abscisic acid (aba), when included in the incubation medium, reduced the elongation of the axes whereas fusicoccin stimulated it; however, th ...197924317869
degradation of the endosperm cell walls of lactuca sativa l., cv. grand rapids in relation to the mobilisation of proteins and the production of hydrolytic enzymes in the axis, cotyledons and endosperm.the timing of changes in total nitrogen and soluble amino nitrogen content, and in the activities of proteinase (ph 7.0), isocitrate lyase, catalase, phytase, phosphatase (ph 5.0), α-galactosidase and β-mannosidase were studied in extracts from the cotyledons, axis and endosperms of germinating and germinated light-promoted lettuce seeds. the largest amount of total nitrogen (2.7% seed dry weight) occurs within the cotyledons, as storage protein. as this decreases the total nitrogen content of t ...197924318187
interaction of [(3)h]gibberellin a 1 with a sub-cellular fraction from lettuce (lactuca sativa l.) hypocotyls : i. kinetics of labelling.the distribution of [(3)h]gibberellin a1 ([(3)h]ga1) amongst sub-cellular fractions from lettuce (lactuca sativa l.) hypocotyl sections was examined by differential centrifugation. material pelleting at 2000 g (2kp) accounted for 2-5% of the total tissue radioactivity and no other significant interactions were detected. after rigorous washing procedures, the 2kp fraction was found to consist mainly of cell wall material and the radioactivity remained associated during sucrose density-gradient ce ...197924318189
interaction of [(3)h] gibberellin a 1 with a sub-cellular fraction from lettuce (lactuca sativa l.) hypocotyls : ii. stability and properties of the association.radioactive 2,000 g pellets (2kp) derived from lettuce (lactuca sativa) hypocotyl sections incubated with [(3)h]gibberellin a1 ([(3)h]ga1) were subjected to a range of treatments to test the stability of labelling. the labelled association was stable in 0.1 m buffer at ph 3 and ph 9 and also in 1 m salt, organic solvents, protease or cellulase. both 1 m potassium hydroxide (koh) and a quaternary ammonium hydroxide tissue solubiliser effected an 80% release of incorporated [(3)h]. no radioactivit ...197924318190
seed germination, root elongation, root-tip mitosis, and micronucleus induction of five crop plants exposed to chromium in fluvo-aquic soil.the present study aimed to determine the toxic effects of chromium (cr) on cabbage (brassica oleracea), cucumber (cucumis sativus), lettuce (lactuca sativa), wheat (triticum aestivum), and corn (zea mays), and identify the sensitive plant species and appropriate bioassays for potential use in phytotoxicity assessment of cr in soil. results showed that seed germination might not be a sensitive assay for assessing cr toxicity because at most of the cr levels there were no toxic effects. root elong ...201424318542
microrna319a-targeted brassica rapa ssp. pekinensis tcp genes modulate head shape in chinese cabbage by differential cell division arrest in leaf regions.leafy heads of cabbage (brassica oleracea), chinese cabbage (brassica rapa), and lettuce (lactuca sativa) are composed of extremely incurved leaves. the shape of these heads often dictates the quality, and thus the commercial value, of these crops. using quantitative trait locus mapping of head traits within a population of 150 recombinant inbred lines of chinese cabbage, we investigated the relationship between expression levels of microrna-targeted brassica rapa ssp. pekinensis teosinte branch ...201424351684
geochemical characterization and biomonitoring of reclaimed soils in the po river delta (northern italy): implications for the agricultural activities.this geochemical study is focused on the easternmost part of the po river alluvial plain in northern italy, which is interested by widespread agricultural activities, investigating a reclaimed sector of the province of ferrara, known as "valle del mezzano" (mezzano low land, hereafter reported as mll) characterized by peat-rich soils. the chemical-mineralogical characterization of these reclaimed soils is important to compare the local geochemical backgrounds with those recorded in other sectors ...201424374785
fate and transformation products of amine-terminated pamam dendrimers under ozonation and irradiation.this article deals with the degradation of a third-generation (g3) poly(amidoamine) (pamam) dendrimer under ozonation and irradiation. the identification and quantification of g3 pamam dendrimer and its transformation products has been performed by liquid chromatography-electrospray ionization-hybrid quadrupole time-of-flight-mass spectrometry. the dendrimer was completely depleted by ozone in less than 1 min. the effect of ultraviolet irradiation was attributed to hydroxyl-mediated oxidation. t ...201424384376
the role of pentacyclic triterpenoids in the allelopathic effects of alstonia scholaris.alstonia scholaris is a tropical evergreen tree native to south and southeast asia. alstonia forests frequently lack understory species. however, potential mechanisms-particularly the allelochemicals involved-remain unclear. in the present study, we identified allelochemicals of a. scholaris, and clarified the role of allelopathic substances from a. scholaris in interactions with neighboring plants. we showed that the leaves, litter, and soil from a. scholaris inhibited growth of bidens pilosa-a ...201424390624
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