| cadmium-induced cyto- and genotoxicity are organ-dependent in lettuce. | cadmium is a priority pollutant. its mechanisms and effects within different plant organs remain unclear. here, cyto-genotoxicity biomarkers were evaluated in roots and leaves after cd exposure (0, 1, 10, and 50 μm) of the model crop lactuca sativa l. (cv. "reine de mai"). overall, superoxide dismutase (sod) and catalase (cat) activities were stimulated in leaves, where cd accumulation was lower in comparison to that in roots. in roots, sod and peroxidase (pox, apx) activities were stimulated. m ... | 2012 | 22624971 |
| development and application of a 6.5 million feature affymetrix genechip® for massively parallel discovery of single position polymorphisms in lettuce (lactuca spp.). | high-resolution genetic maps are needed in many crops to help characterize the genetic diversity that determines agriculturally important traits. hybridization to microarrays to detect single feature polymorphisms is a powerful technique for marker discovery and genotyping because of its highly parallel nature. however, microarrays designed for gene expression analysis rarely provide sufficient gene coverage for optimal detection of nucleotide polymorphisms, which limits utility in species with ... | 2012 | 22583801 |
| heavy metals in soil and salad in the proximity of historical ferroalloy emission. | emissions of manganese (mn), lead (pb), iron (fe), zinc (zn), copper (cu) from ferro-alloy operations has taken place in valcamonica, a pre-alp valley in the province of brescia, italy, for about a century until 2001. metal concentrations were measured in the soil of local home gardens and in the cultivated vegetables. soil analysis was carried out using a portable x-ray fluorescence (xrf) spectrometer in both surface soil and at 10 cm depth. a subset of soil samples (n = 23) additionally was an ... | 2012 | 27818841 |
| a bayesian analysis of gene flow from crops to their wild relatives: cultivated (lactuca sativa l.) and prickly lettuce (l. serriola l.) and the recent expansion of l. serriola in europe. | interspecific gene flow can lead to the formation of hybrid populations that have a competitive advantage over the parental populations, even for hybrids from a cross between crops and wild relatives. wild prickly lettuce (lactuca serriola) has recently expanded in europe and hybridization with the related crop species (cultivated lettuce, l. sativa) has been hypothesized as one of the mechanisms behind this expansion. in a basically selfing species, such as lettuce, assessing hybridization in n ... | 2012 | 22512715 |
| [analysis of essential oil extracted from lactuca sativa seeds growing in xinjiang by gc-ms]. | to analyze the components of essential oil from lactuca sativa seeds growing in xinjiang. | 2011 | 22500425 |
| crop to wild introgression in lettuce: following the fate of crop genome segments in backcross populations. | after crop-wild hybridization, some of the crop genomic segments may become established in wild populations through selfing of the hybrids or through backcrosses to the wild parent. this constitutes a possible route through which crop (trans)genes could become established in natural populations. the likelihood of introgression of transgenes will not only be determined by fitness effects from the transgene itself but also by the crop genes linked to it. although lettuce is generally regarded as s ... | 2012 | 22448748 |
| utility of bioassays (lettuce, red clover, red fescue, microtox, metstick, hyalella, bait lamina) in ecological risk screening of acid metal (zn) contaminated soil. | the objective of this study was to assess selected bioassays and ecological screening tools for their suitability in a weight of evidence risk screening process of acidic metal contaminated soil. intact soil cores were used for the tests, which minimizes changes in ph and metal bioavailability that may result from homogenization and drying of the soil. soil cores were spiked with zncl(2) or cacl(2). leachate collected from the soil cores was used to account for the exposure pathways through pore ... | 2012 | 22444727 |
| defensive sesquiterpenes from senecio candidans and s. magellanicus, and their structure-activity relationships. | eleven eremophilanolides, 1-3 and 6-13, and two eremophilanes, 24 and 25, were isolated from senecio candidans and s. magellanicus from the magallanes region (chile). compounds 2, 3, 9, and 10 have not been previously reported as natural products. their structures were established by nmr spectroscopic analysis and chemical transformations. the x-ray analysis of compounds 11, 13, and 17 were also performed. different semisynthetic analogs from eremophilanolide 11 were generated to carry out a str ... | 2012 | 22422530 |
| mapping qtl, epistasis and genotype × environment interaction of antioxidant activity, chlorophyll content and head formation in domesticated lettuce (lactuca sativa). | fruits and vegetables are rich sources of antioxidants in human diets and their intake is associated with chronic disease prevention. lettuce (lactuca sativa l.) is a common vegetable in diets worldwide, but its nutritional content is relatively low. to elucidate the genetic basis of antioxidant content in lettuce, we measured the oxygen radical absorbance capacity (orac) and chlorophyll (chl) content as a proxy of β-carotene in an f(8) recombinant inbred line (ril) in multiple production cycles ... | 2012 | 22327242 |
| carotenoids of lettuce (lactuca sativa l.) grown on soil enriched with spent coffee grounds. | the impact of spent coffee grounds on carotenoid and chlorophyll content in lettuce (lactuca sativa l. var. capitata) was evaluated. a greenhouse pot experiment was conducted with spent coffee amounts ranging from 0% to 20% (v/v). all evaluated pigments increased proportionally to spent coffee amounts. lutein and β-carotene levels increased up to 90% and 72%, respectively, while chlorophylls increased up to 61%. biomass was also improved in the presence of 2.5% to 10% spent coffee, decreasing fo ... | 2012 | 22314378 |
| preliminary studies on growth and fresh weight of lettuce (lactuca sativa) as affected by clay pot irrigation and spacing. | an experiment (completely randomized design) was set up to determine the effects of clay pot sub-surface irrigation (cpsi) and spacing on the growth and fresh weight of lettuce (lactuca sativa). the treatments were: cpsi with spacing; 15 x 15 cm, 20 x 20 cm and 30 x 30 cm. control treatments were watering can irrigation (wci) with the same spacing as above. treatments were replicated three times given a total of 18 experimental units. eighteen large enamel basins of 50/20 cm (diameter/height) we ... | 2011 | 22308659 |
| 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. | 2012 | 23950014 |
| potent endogenous allelopathic compounds in lepidium sativum seed exudate: effects on epidermal cell growth in amaranthus caudatus seedlings. | many plants exude allelochemicals--compounds that affect the growth of neighbouring plants. this study reports further studies of the reported effect of cress (lepidium sativum) seed(ling) exudates on seedling growth in amaranthus caudatus and lactuca sativa. in the presence of live cress seedlings, both species grew longer hypocotyls and shorter roots than cress-free controls. the effects of cress seedlings were allelopathic and not due to competition for resources. amaranthus seedlings grown i ... | 2012 | 22268144 |
| phytotoxic activity in flourensia campestris and isolation of (--)-hamanasic acid a as its active principle compound. | an aqueous extract from flourensia campestris (asteraceae) dry aerial parts showed strong inhibition on the germination and growth of lactuca sativa. based on bio-guided chromatographic fractionation of aq. extracts from dry and fresh leaves and spectroscopic means, (-)-hamanasic acid a (7-carboxy-8-hydroxy-1(2), 12(13)-dien-bisabolene (1)) was isolated as the most inhibitory active principle on germination (ecg(50)=2.9 mm) and on root (ecr(50)=1.5 mm)/shoot (ecs(50)=2.0 mm) growth. as measured ... | 2012 | 22245633 |
| calcium water treatment residue reduces copper phytotoxicity in contaminated sandy soils. | calcium water treatment residue (ca-wtr), an industrial by-product, was found to be effective in decreasing cu availability in contaminated soils and transport to the environment. in this study, a greenhouse study was conducted to test the ability of ca-wtr to reduce the toxicity and uptake of cu by ryegrass (lolium perenne l.) and lettuce (lactuca sativa l.) as indicator crop plants in cu-contaminated sandy soils. eight weeks growing period was observed in alfisol and spodosol amended with diff ... | 2012 | 22138174 |
| ethylene reduces plant gas exchange and growth of lettuce grown from seed to harvest under hypobaric and ambient total pressure. | naturally occurring high levels of ethylene can be a problem in spaceflight and controlled environment agriculture (cea) leading to sterility and irregular plant growth. there are engineering and safety advantages of growing plants under hypobaria (low pressure) for space habitation. the goals of this research were to successfully grow lettuce (lactuca sativa cv. buttercrunch) in a long-term study from seed to harvest under hypobaric conditions, and to investigate how endogenously produced ethyl ... | 2012 | 22118875 |
| predicting effects of cations on copper toxicity to lettuce (lactuca sativa) by the biotic ligand model. | a biotic ligand model (blm) was developed to estimate cu toxicity to lettuce (lactuca sativa) in terms of root elongation after 4 d of exposure. effects of na(+), k(+), ca(2+), and mg(2+) on cu toxicity were examined. the addition of these cations resulted in a 50-fold difference in the copper median effective activity (ec50 cu2+). however, these variations could not be interpreted entirely as a function of the concentrations of these cations alone. in particular, only the relationship between e ... | 2012 | 22105443 |
| a chlorophyll fluorescence analysis of photosynthetic efficiency, quantum yield and photon energy dissipation in psii antennae of lactuca sativa l. leaves exposed to cinnamic acid. | this study investigated the effects of cinnamic acid (ca) on growth, biochemical and physiological responses of lactuca sativa l. ca (0.1, 0.5, 1.0 and 1.5 mm) treatments decreased plant height, root length, leaf and root fresh weight, but it did not affect the leaf water status. ca treatment (1.5 mm) significantly reduced f(v), f(m), photochemical efficiency of psii (f(v)/f(m)) and quantum yield of psii (φpsii) photochemistry in l. sativa. the photochemical fluorescence quenching (qp) and non-p ... | 2011 | 22000052 |
| toxicity of the effluent from an anaerobic bioreactor treating cereal residues on lactuca sativa. | effluents generated during the process of anaerobic digestion should be treated before their disposal into the environment. the aim of this study was evaluating the effectiveness of the effluent treatment system from an anaerobic bioreactor, assessing the toxicity reduction with the lactuca sativa seed germination and root elongation inhibition test. three sampling points were selected along the effluent treatment system: inflow into the first treatment pond, outflow from the third pond and reci ... | 2012 | 21993347 |
| conventional, organic and biodynamic farming: differences in polyphenol content and antioxidant activity of batavia lettuce. | lactuca sativa l. ssp. acephala l., cv. batavia red mohican plants were cultivated under intensive conventional, organic and biodynamic farming and were analyzed for their polyphenol content and antiradical activity in order to demonstrate the influence of farming on yield, polyphenol content and antiradical activity. | 2012 | 21935957 |
| application of molecular techniques to identification of three plusiine species, autographa nigrisigna, macdunnoughia confusa, and thysanoplusia intermixta (lepidoptera: noctuidae), found in integrated pest management lettuce fields in japan. | three plusiine species, autographa nigrisigna, macdunnoughia confusa, and thysanoplusia intermixta (lepidoptera: noctuidae), are commonly found together in lettuce, lactuca sativa l., fields in japan. given the marked morphological similarities between these species and the difficulty associated with discriminating between them using only visual cues, we used multiplex polymerase chain reaction (pcr) assay to distinguish between the three target species. multiplex pcr uses four primers to simult ... | 2011 | 21882693 |
| locus-dependent selection in crop-wild hybrids of lettuce under field conditions and its implication for gm crop development. | gene escape from crops has gained much attention in the last two decades, as transgenes introgressing into wild populations could affect the latter's ecological characteristics. however, different genes have different likelihoods of introgression. the mixture of selective forces provided by natural conditions creates an adaptive mosaic of alleles from both parental species. we investigated segregation patterns after hybridization between lettuce (lactuca sativa) and its wild relative, l. serriol ... | 2011 | 25568012 |
| evaluation of the phytotoxicity of polycontaminated industrial effluents using the lettuce plant (lactuca sativa) as a bioindicator. | industrial wastewater containing heavy metals is generally decontaminated by physicochemical treatment consisting in insolublizing the contaminants and separating the two phases, water and sludge, by a physical process (filtration, settling or flotation). however, chemical precipitation does not usually remove the whole pollution load and the effluent discharged into the environment can be toxic even if it comes up to regulatory standards. to assess the impact of industrial effluent from 4 diffe ... | 2011 | 21835466 |
| pilot study of the efficacy and safety of lettuce seed oil in patients with sleep disorders. | lactuca sativa (garden lettuce) is a popular salad herb. it has been in use in folk medicine since ancient times as both an appetite stimulant and as an aid to sleep. l. sativa seed oil (sedan(®)) has demonstrated a pronounced sedative effect and potentiated the hypnotic effect of barbiturates in animal models. it also exhibited significant analgesic and anti-inflammatory activities. in this study, we evaluated the sedative and hypnotic effects of l. sativa in patients suffering from insomnia. | 2011 | 21731897 |
| anthocyanin content and the activities of polyphenol oxidase, peroxidase and phenylalanine ammonia-lyase in lettuce cultivars. | anthocyanin content and the activities of polyphenol oxidase (ppo), peroxidase (pod) and phenylalanine ammonia-lyase (pal) and their relationships were determined in the leaves of six lettuce (lactuca sativa l.) cultivars, exposed for 6 weeks to alternating three different day/night temperatures. anthocyanin content was found to be highest at 20/13°c, followed by 25/20°c and 30/25°c, showing accumulation of anthocyanin at low temperatures. activities of ppo and pal were also found to be highest ... | 2012 | 21718113 |
| beneficial effects of exogenous iodine in lettuce plants subjected to salinity stress. | salinity inhibits plant growth due to ionic and osmotic effects on metabolic processes and nutritional balance, leading to impaired physiological functions. selenium (se) and silicon (si) can be partially alleviated by the effects wrought by nacl on the plant metabolism. iodine (i), applied as iodate (io(3)(-)) in biofortification programmes, has been confirmed to improve the antioxidant response in lettuce plants. thus, the aim of this study was to determine whether the application of io(3)(-) ... | 2011 | 21683885 |
| using response surface methodology to assess the effects of iron and spent mushroom substrate on arsenic phytotoxicity in lettuce (lactuca sativa l.). | the effects of iron (fe) and spent mushroom substrate (sms) arsenic (as) phytotoxicity towards lettuce in artificial soils were investigated to separate the adverse soil parameters relating to as toxicity using a response surface methodology. sms induced the root elongation of lettuce in both control and as-treated soils. however, in phytotoxicity test using a median effective concentration (ec(50)) of as, fe and the interaction between both parameters (fe*sms) significantly affected ec(50), whi ... | 2011 | 21632176 |
| toxicity of polyfluorinated and perfluorinated compounds to lettuce (lactuca sativa) and green algae (pseudokirchneriella subcapitata). | recently, polyfluorinated and perfluorinated compounds (pfcs) have been detected in most surface waters around the world. because some pfcs are persistent and tend to accumulate in surface waters, their potential adverse effects to aquatic organisms have received increasing attention. nevertheless, currently available toxicity information is limited. the aim of this study was to evaluate the toxicity effects of seven pfcs on root elongation of lettuce (lactuca sativa) and photosynthesis of green ... | 2012 | 21626016 |
| bioavailability of copper, cadmium, zinc, and lead in tropical savanna soils assessed by diffusive gradient in thin films (dgt) and ion exchange resin membranes. | the technique of diffusion gradient in thin films (dgt) for assessing bioavailable metals has not been tested under field conditions. we assessed the relationships of dgt- and cation exchange resin-membrane-measured concentrations of cd, cu, pb, and zn with plant uptake of the metals under greenhouse and field conditions. in the greenhouse, the effective concentrations of cu, pb, and zn by dgt correlated significantly with uptake by sorghum (sorghum bicolor), but cation exchange resin-membrane-m ... | 2012 | 21590301 |
| ecotoxicity of chlorophenolic compounds depending on soil characteristics. | three chlorophenolic compounds (2-chlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol) were tested to assess their effects on two soils with different properties: a granitic soil (haplic arenosol) and a calcareous one (calcaric regosol). different concentrations of the pollutants (ranging from 0.001 to 10,000 mg kg(-1) soil, d.w.) were assayed for their effects on soil microbial activity and composition, using manometric respirometry and pcr-dgge analysis, respectively. other ecotoxicity ... | 2011 | 21531445 |
| bioactive saponins from microsechium helleri and sicyos bulbosus. | eleven oleanane-type saponins (1-11) have been isolated from microsechium helleri and sicyos bulbosus roots and were evaluated for their antifeedant, nematicidal and phytotoxic activities. saponins {3-o-β-d-glucopyranosyl (1→3)-β-d-glucopyranosyl-2β,3β,16α,23-tetrahydroxyolean-12-en-28-oic acid 28-o-α-l-rhamnopyranosyl-(1→3)-β-d-xylopyranosyl-(1→4)-[β-d-xylopyranosyl-(1→3)]-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranoside} (1), and {3-o-β-d-glucopyranosyl-2β,3β,16α,23-tetrahydroxyolean-12-en-28-o ... | 2011 | 21439597 |
| analysis of eleven phenolic compounds including novel p-coumaroyl derivatives in lettuce (lactuca sativa l.) by ultra-high-performance liquid chromatography with photodiode array and mass spectrometry detection. | lettuce is a widely consumed vegetable and a good source of phenolic compounds. several factors (genetic, agronomical and environmental) can influence the lettuce composition; their effects are not completely defined and more studies are needed on this topic. | 2017 | 21433163 |
| effects of microcystin-lr, linear alkylbenzene sulfonate and their mixture on lettuce (lactuca sativa l.) seeds and seedlings. | microcystin-lr (mclr) and linear alkylbenzene sulfonate (las) are present widely in aquatic and terrestrial ecosystems, but their combined ecotoxicological risk is unknown. this study investigated the toxic effects of mclr, las and their mixture on lettuce (lactuca sativa l.) and evaluated mclr accumulation level in lettuce with or without las. the changes in seed germination and shoot/root growth, responses of the antioxidative defense system, and the accumulation of mclr in lettuce were tested ... | 2011 | 21409590 |
| molecular cloning and characterization of 4-hydroxyphenylpyruvate dioxygenase gene from lactuca sativa. | vitamin e has been found to be associated with an important antioxidant property in mammals and plants. in photosynthetic organisms, the enzyme 4-hydroxyphenylpyruvate dioxygenase (hppd; e.c. 1.13.11.27) plays an important role in the vitamin e biosynthetic pathway. the full-length cdna encoding hppd was isolated from lactuca sativa l. by rapid amplification of cdna ends (race). the cdna, designated as lshppd, was 1743 base pairs (bp) long containing an open reading frame (orf) of 1338 bp encodi ... | 2011 | 21349599 |
| inhibition of photosynthetic oxygen evolution and electron transfer from the quinone acceptor qa- to qb by iron deficiency. | the effect of iron deficiency on photosynthetic electron transport in photosystem ii (ps ii) was studied in leaves and thylakoid membranes of lettuce (lactuca sativa, romaine variety) plants. ps ii electron transport was characterized by oxygen evolution and chlorophyll fluorescence parameters. iron deficiency in the culture medium was shown to affect water oxidation and the advancement of the s-states. a decrease of maximal quantum yield of ps ii and an increase of fluorescence intensity at ste ... | 2011 | 21311974 |
| selenium accumulation in lettuce germplasm. | selenium (se) is an essential micronutrient for animals and humans. increasing se content in food crops offers an effective approach to reduce the widespread selenium deficiency problem in many parts of the world. in this study, we evaluated 30 diverse accessions of lettuce (lactuca sativa l.) for their capacity to accumulate se and their responses to different forms of se in terms of plant growth, nutritional characteristics, and gene expression. lettuce accessions responded differently to sele ... | 2011 | 21153555 |
| heavy metal removal from industrial effluents by sorption on cross-linked starch: chemical study and impact on water toxicity. | batch sorption experiments using a starch-based sorbent were carried out for the removal of heavy metals present in industrial water discharges. the influence of contact time, mass of sorbent and pollutant load was investigated. pollutant removal was dependent on the mass of sorbent and contact time, but independent of the contaminant load. the process was uniform, rapid and efficient. sorption reached equilibrium in 60 min irrespective of the metal considered (e.g. zn, pb, cu, ni, fe and cd), r ... | 2011 | 21067859 |
| accumulation of heavy metals from contaminated soil to plants and evaluation of soil remediation by vermiculite. | we evaluated the distribution of 15 metal ions, namely al, cd, cu, cr, fe, la, mn, ni, pb, sc, ti, v, y, zn and zr, in the soil of a contaminated site in piedmont (italy). this area was found to be heavily contaminated with cu, cr and ni. the availability of these metal ions was studied using tessier's sequential extraction procedure: the fraction of mobile species, which potentially is the most harmful for the environment, was much higher than that normally present in unpolluted soils. this soi ... | 2011 | 21055788 |
| effects of industrial waste water on heavy metal accumulation, growth and biochemical responses of lettuce (lactuca sativa l.). | the waste water showed high values of total solid (ts), hardness and chloride with slightly alkaline ph along with high concentrations of cr (2.03 mg l(-1)), ni (1.59 mg l(-1)) and zn (0.46 mg l(-1)). the concentration of cu (0.21 mg l(-1)) and zn in industrial waste water was low than ni and cr. the diluted (25 and 50%), undiluted (100%) waste water was used to irrigate the lettuce plants grown in alluvial soils. plants accumulated heavy metals in their shoot (ni, 13.65; cr, 19.73; zn, 21.6 and ... | 2010 | 21046995 |
| potential of a metal-organic framework as a new material for solid-phase extraction of pesticides from lettuce (lactuca sativa), with analysis by gas chromatography-mass spectrometry. | the metal-organic framework (∞)[(la(0.9)eu(0.1))(2)(dpa)(3)(h(2)o)(3)] was tested for extraction of pyrimicarb, procymidone, malathion, methyl parathion and α- and β-endosulfan from lettuce, with analysis using gc/ms in sim mode. experiments were carried out in triplicate at two fortification levels (0.1 and 0.5 mg/kg), and resulted in recoveries in the range of 78-107%, with rsd values between 1.6 and 8.0% for (∞)[(la(0.9)eu(0.1))(2)(dpa)(3)(h(2)o)(3)] sorbent. detection and quantification limi ... | 2010 | 20972975 |
| testing the validity of a cd soil quality standard in representative mediterranean agricultural soils under an accumulator crop. | the validity of a quality standard for cadmium (cd) in representative agricultural mediterranean soils under an accumulator crop (lactuca sativa l.) is evaluated in this work considering both its effect on the crop growth (biomass production) and the metal accumulation in the edible part of the plant. four soils with different properties relevant to regulate the behaviour of heavy metals were selected from the valencian region, a representative area of the european mediterranean region. for all ... | 2010 | 20947133 |
| existence of vigorous lineages of crop-wild hybrids in lettuce under field conditions. | plant to plant gene flow is a route of environmental exposure for gm plants specifically since crosses with wild relatives could lead to the formation of more vigorous hybrids, which could increase the rate of introgression and the environmental impact. here, we test the first step in the process of potential transgene introgression: whether hybrid vigor can be inherited to the next generation, which could lead to fixation of altered, i.e., elevated, quantitative traits. the potential for a perm ... | 2010 | 20883659 |
| use of arsenic contaminated irrigation water for lettuce cropping: effects on soil, groundwater, and vegetal. | the present study investigated the effects of using arsenic (as) contaminated irrigation water in lactuca sativa l. cropping. two different arsenic concentrations, i.e., 25 and 85 μg l(-1) and two different soils, i.e., sandy and clay loam, were taken into account. we determined the arsenic mobility in the different soil fractions, its amount in groundwater, and the phytotoxicity and genotoxicity. nuclear magnetic resonance (nmr) and inductively coupled plasma (icp) were used to assess the lettu ... | 2011 | 20882365 |
| can δ(15)n in lettuce tissues reveal the use of synthetic nitrogen fertiliser in organic production? | the nitrogen isotopic fingerprint (δ(15)n) is reported to be a promising indicator for differentiating between organically and conventionally grown vegetables. however, the effect on plant δ(15)n of split nitrogen fertilisation, which could enable farmers to cover up the use of synthetic fertiliser, is not well studied. in this study the use of δ(15)n in lettuce as a potential marker for identifying the use of synthetic nitrogen fertiliser was tested on pot-grown lettuce (lactuca sativa l.) trea ... | 2011 | 20862716 |
| phytotoxicity of sarmentine isolated from long pepper (piper longum) fruit. | discovery of novel natural herbicides has become crucial to overcome increasing weed resistance and environmental issues. in this article, we describe the finding that a methanol extract of dry long pepper (piper longum l.) fruits is phytotoxic to lettuce (lactuca sativa l.) seedlings. the bioassay-guided fractionation and purification of the crude extract led to isolation of sarmentine (1), a known compound, as the active principle. phytotoxicity of 1 was examined with a variety of seedlings of ... | 2010 | 20839888 |
| characterization of volatile production during storage of lettuce (lactuca sativa) seed. | the duration that seeds stay vigorous during storage is difficult to predict but critical to seed industry and conservation communities. production of volatile compounds from lettuce seeds during storage was investigated as a non-invasive and early detection method of seed ageing rates. over 30 volatile compounds were detected from lettuce seeds during storage at 35 degrees c at water contents ranging from 0.03 to 0.09 g h(2)o g(-1) dw. both qualitative and quantitative differences in volatile c ... | 2010 | 20819791 |
| quantitative trait loci associated with longevity of lettuce seeds under conventional and controlled deterioration storage conditions. | lettuce (lactuca sativa l.) seeds have poor shelf life and exhibit thermoinhibition (fail to germinate) above ∼25°c. seed priming (controlled hydration followed by drying) alleviates thermoinhibition by increasing the maximum germination temperature, but reduces lettuce seed longevity. controlled deterioration (cd) or accelerated ageing storage conditions (i.e. elevated temperature and relative humidity) are used to study seed longevity and to predict potential seed lifetimes under conventional ... | 2010 | 20693410 |
| identification of three relationships linking cadmium accumulation to cadmium tolerance and zinc and citrate accumulation in lettuce. | lettuce (lactuca sativa) is a plant species that shows high accumulation of cadmium, a toxic heavy metal. lettuce is therefore a good model both for identifying determinants controlling cadmium accumulation in plant tissues and for developing breeding strategies aimed at limiting cadmium accumulation in edible tissues. in this work, 14-day-old plants from three lettuce varieties were grown for 8 days on media supplemented with cadmium concentrations ranging from 0 to 50 microm. growth, as well a ... | 2010 | 20576318 |
| constituents of calamintha ashei: effects on florida sandhill species. | chemical constituents of the perennial shrub calamintha ashei have been characterized as part of our investigation of the allelopathic properties of this plant. besides the known monoterpenes, (+)-evodone, (-)-calaminthone and (+)-desacetylcalaminthone, fresh aerial parts of c. ashei provided six new menthofurans, two new germacrane sesquiterpenes, and the six, known flavonoids: 5-desmethoxynobiletin, 5-hydroxy-6,7,8,4'-tetramethoxyflavone, 5,4'-dihydroxy-6,7,8,3'-tetramethoxyflavone, thymonin, ... | 2010 | 20521531 |
| effects of seasonal variation on sensory properties and total phenolic content of 5 lettuce cultivars. | butterhead, crisphead, green leaf, red leaf, and romaine types of lettuce (lactuca sativa l.) are all commonly available in u.s. markets. sensory properties of lettuce may vary in response to environmental factors that often fluctuate widely throughout the growing season. bitterness is generally thought to increase in lettuce grown at higher temperatures and may be related to phenolic content. this study evaluated sensory properties and total phenolic content of 5 lettuce cultivars harvested ear ... | 2010 | 20492312 |
| light-induced root hair formation in lettuce (lactuca sativa l. cv. grand rapids) roots at low ph is brought by chlorogenic acid synthesis and sugar. | previously, we reported that chlorogenic acid (cga) facilitated root hair formation at ph 4.0 in lettuce (lactuca sativa l. cv. grand rapids). light was essential for this process. in the present study, we determined relationships between cga, light, and sugar during root hair formation in lettuce seedlings. the amount of cga increased with white light in intact seedlings. exogenously applied cga restored root hair formation in dark-grown intact seedlings at ph 4.0. however, no root hair formati ... | 2010 | 20437192 |
| metal uptake in a peri-urban lactuca sativa cultivated area. | in this study, two lactuca sativa crops grown in a net-protected site and an unprotected site were compared. the results showed metals were accumulated by lactuca sativa. higher metal accumulation in lettuce grown in the unprotected parcel was established, and the only significant differences in their physicochemical properties were cation exchange capacity and exposure to sunlight. exposure to the sun may translate into higher soil-plant flux of water and/or higher decomposition rate of organic ... | 2010 | 20390850 |
| spermine delays leaf senescence in lactuca sativa and prevents the decay of chloroplast photosystems. | aliphatic polyamines (pas) are involved in the delay or prevention of plant senescence, but the molecular mechanism is not clarified. the hypothesis is put forward that one of the mechanisms by which pas modulate leaf senescence and chlorophyll stabilisation could be due to their modification of chlorophyll-bound proteins, catalysed by transglutaminase (tgase, r-glutaminylpeptide-amine gamma-glutamyltransferase; e.c. 2.3.2.13). the retardation of leaf senescence of lactuca sativa l. by spermine ... | 2010 | 20381367 |
| effect of water treatment residuals on soil phosphorus, copper and aluminium availability and toxicity. | water treatment residuals (wtrs) are produced by the treatment of potable water with coagulating agents. beneficial recycling in agriculture is hampered by the fact that wtrs contain potentially toxic contaminants (e.g. copper and aluminium) and they bind phosphorus strongly. these issues were investigated using a plant bioassay (lactuca sativa), chemical extractions and an isotopic dilution technique. two wtrs were applied to an acidic and a neutral ph soil at six rates. reductions in plant gro ... | 2010 | 20378219 |
| regulation of cell division and growth in roots of lactuca sativa l. seedlings by the ent-kaurene diterpenoid rabdosin b. | rabdosin b, an ent-kaurene diterpenoid purified from the air-dried aerial parts of isodon japonica (burm.f) hara var. galaucocalyx (maxin) hara, showed a biphasic, dose-dependent effect on root growth and a strong inhibitory effect on root hair development in lettuce seedlings (lactuca sativa l.). lower concentrations of rabdosin b (20-80 microm) significantly promoted root growth, but its higher levels at 120-200 microm, by contrast, had inhibitory effects. additionally, all tested concentratio ... | 2010 | 20376693 |
| biofortification of lettuce (lactuca sativa l.) with iodine: the effect of iodine form and concentration in the nutrient solution on growth, development and iodine uptake of lettuce grown in water culture. | iodine is an essential trace element for humans. two billion individuals have insufficient iodine intake. biofortification of vegetables with iodine offers an excellent opportunity to increase iodine intake by humans. the main aim was to study the effect of iodine form and concentration in the nutrient solution on growth, development and iodine uptake of lettuce, grown in water culture. | 2010 | 20355129 |
| allelochemical, eudesmane-type sesquiterpenoids from inula falconeri. | we have identified through bioassay guided isolation an allelochemical, eudesmane-type sesquiterpeniod, 3beta-caffeoxyl-beta1,8alpha-dihydroxyeudesm-4(15)-ene (1), from an endemic plant species growing in the himalayas. in our search for the bioactive subfraction, the hexane one was highly significant, showing 100% inhibition of lettuce seed growth at 100 ppm while other subfractions (chloroform, ethyl acetate, butanol and water) exhibited inhibitory to stimulatory allelopathic effects. the bioa ... | 2010 | 20336000 |
| modification of cell wall properties in lettuce improves shelf life. | it is proposed that post-harvest longevity and appearance of salad crops is closely linked to pre-harvest leaf morphology (cell and leaf size) and biophysical structure (leaf strength). transgenic lettuce plants (lactuca sativa cv. valeria) were produced in which the production of the cell wall-modifying enzyme xyloglucan endotransglucosylase/hydrolase (xth) was down-regulated by antisense inhibition. independently transformed lines were shown to have multiple members of the lsxth gene family do ... | 2010 | 20179011 |
| phytoavailability of cadmium in long-term biosolids-amended soils. | agronomic use of biosolids has raised concern that plant availability of biosolids-cd will increase with time after cessation of biosolids application. it has been demonstrated that chemical extractability of cd is persistently decreased in biosolids-amended soils. this study was conducted to determine if cd phytoavailability in long-term biosolids-amended soils was also persistently decreased. paired control and biosolids-amended soils were collected from three experimental sites where large cu ... | 2017 | 20176825 |
| the effect of cyanide compounds, fluorides, aluminum, and inorganic oxides present in spent pot liner on germination and root tip cells of lactuca sativa. | spl (spent pot liner) is a solid waste produced by the aluminum industry. this waste has a highly variable composition, consisting of cyanides, fluorides, organics, and metals. the aim of this work was to study the effect of spl on root tips of lactuca sativa using current plant bioassays. we observed a decrease in the germination rate with increasing concentrations of spl. in addition, spl was found to reduce root growth, which is correlated with a decrease in the mitotic index. nevertheless, w ... | 2010 | 20092896 |
| toxicity assessment of garden soils in the vicinity of mining areas in southern morocco. | the aim of the present work is the assessment of the concentration, toxicity and phytoavailability of heavy metals in garden soils in the vicinity of three mines (a, b and c) in south of morocco by using concurrently selective chemical extractions, metplate a toxicity bioassay and plant growth experiments. the tailings materials containing very high concentrations of mn, cu and co in mine a, co, mn, cr and ni in mine b and cu and zn in mine c. the high toxicity of tailings from mine c (86.7% inh ... | 2010 | 20074853 |
| foliar lead uptake by lettuce exposed to atmospheric fallouts. | metal uptake by plants occurs by soil-root transfer but also by direct transfer of contaminants from the atmosphere to the shoots. this second pathway may be particularly important in kitchen gardens near industrial plants. the mechanisms of foliar uptake of lead by lettuce ( lactuca sativa ) exposed to the atmospheric fallouts of a lead-recycling plant were studied. after 43 days of exposure, the thoroughly washed leaves contained 335 +/- 50 mg pb kg(-1) (dry weight). micro-x-ray fluorescence m ... | 2010 | 20063891 |
| ecological risks of an old wood impregnation mill: application of the triad approach. | although many studies deal with the distribution and mobility of chromated copper arsenate (cca) metals in soil, the ecotoxicity of cca-contaminated soils is rarely studied. the triad approach was applied to determine the ecological risks posed by a cca mixture at a decommissioned wood impregnation mill in southern finland. a combination of (1) chemical analyses; (2) toxicity tests with plants (aquatic: lemna minor; terrestrial: lactuca sativa), earthworms (lumbricus rubellus), and enchytraeids ... | 2009 | 20050027 |
| a genetic locus and gene expression patterns associated with the priming effect on lettuce seed germination at elevated temperatures. | seeds of most cultivated varieties of lettuce (lactuca sativa l.) fail to germinate at warm temperatures (i.e., above 25-30 degrees c). seed priming (controlled hydration followed by drying) alleviates this thermoinhibition by increasing the maximum germination temperature. we conducted a quantitative trait locus (qtl) analysis of seed germination responses to priming using a recombinant inbred line (ril) population derived from a cross between l. sativa cv. salinas and l. serriola accession uc9 ... | 2010 | 20047028 |
| nmr-metabolic methodology in the study of gm foods. | the 1h-nmr methodology used in the study of genetically modified (gm) foods is discussed. transgenic lettuce (lactuca sativa cv "luxor") over-expressing the arabidopsisknat1 gene is presented as a case study. twenty-two water-soluble metabolites (amino acids, organic acids, sugars) present in leaves of conventional and gm lettuce were monitored by nmr and quantified at two developmental stages. the nmr spectra did not reveal any difference in metabolite composition between the gm lettuce and the ... | 2010 | 22253988 |
| association mapping and marker-assisted selection of the lettuce dieback resistance gene tvr1. | lettuce (lactuca saliva l.) is susceptible to dieback, a soilborne disease caused by two viruses from the family tombusviridae. susceptibility to dieback is widespread in romaine and leaf-type lettuce, while modern iceberg cultivars are resistant to this disease. resistance in iceberg cultivars is conferred by tvr1 - a single, dominant gene that provides durable resistance. this study describes fine mapping of the resistance gene, analysis of nucleotide polymorphism and linkage disequilibrium in ... | 2009 | 19930659 |
| irrigation with treated wastewater: effects on soil, lettuce (lactuca sativa l.) crop and dynamics of microorganisms. | the aim of this study was to evaluate the applicability of treated wastewater for horticultural crops, assess the effects of continuous use of treated water on soil and crops, and analyse the physical, chemical and biological effects of irrigation with recycled water. two lettuce plots watered with drinking water and treated wastewater were monitored over a three year period. nutrients, heavy metal and the dynamics of pathogen and indicator microorganism content in soil and foliar tissues were a ... | 2009 | 19847714 |
| sewage sludge sugarcane trash based compost and synthetic aggregates as peat substitutes in containerized media for crop production. | effect of partial substitution of peat in growth media by sewage sludge sugarcane trash based compost (ssc) and synthetic aggregates (sa) on the physical and chemical characteristics of the growth media and on the growth and nutrition of lettuce (lactuca sativa l.) grown in the substituted media was investigated under this study. ssc was produced from sugarcane trash and sewage sludge. unconventional sa were produced by low productive acidic red soil with paper waste and starch waste. the treatm ... | 2010 | 19828249 |
| antifeedant and cytotoxic activity of longipinane derivatives. | the polyoxygenated longipinane derivatives 1- 8 were tested as antifeedant compounds against the herbivorous insects spodoptera littoralis, rhopalosiphum padi, and myzus persicae. compounds 1-3 and 8 exhibited significant antifeedant activity against s. littoralis and m. persicae. the antifeedant activity against s. littoralis increased moderately after the c-8 hydroxy group in 3 was removed to afford 1 and increased strongly after the remaining two hydroxy groups were acetylated to afford 2. co ... | 2010 | 19742424 |
| nitrate content of lettuce (lactuca sativa l.) after fertilization with sewage sludge and irrigation with treated wastewater. | a romaine-type lettuce (lactuca sativa l.) was cultivated over three crop seasons (spring 2005, spring 2006 and autumn-winter 2006) in six 36 m(2) plots in alcázar de san juan, spain. a drip irrigation system was used to water all plots: five plots with drinking water and one plot with wastewater from the activated sludge system of a wastewater treatment plant (wwtp). one drinking water-irrigated plot was not fertilized (control). five different treatments were applied to the soil: three organic ... | 2009 | 19680887 |
| toxicity assessment from electro-coagulation treated-textile dye wastewaters by bioassays. | in this study the pollutant removal from a textile dyeing wastewater has been investigated by using the electro-coagulation technique with iron electrodes. in order to obtain optimal values of the system state variables, a 3(3) full factorial experimental design was applied. the electro-coagulation (ec) process response was evaluated on the basis of cod removal and decolourization values. the electrolysis time and density current were statistically significant for the cod removal and decolouriza ... | 2009 | 19640647 |
| phytotoxicity tests of solid wastes and contaminated soils in the czech republic. | the purpose of this study was to compare the suitability of different phytotoxicity testing procedures for the evaluation of toxicity associated with both soil contamination and solid wastes, both of which can be of environmental risk to plants. ten different representative types of contaminated soils and solid waste samples were chosen from the czech republic. | 2010 | 19557447 |
| use of spent mushroom substrates from agaricus subrufescens (syn. a. blazei, a. brasiliensis) and lentinula edodes productions in the enrichment of a soil-based potting media for lettuce (lactuca sativa) cultivation: growth promotion and soil bioremediation. | this study aimed to assess physicochemical and microbiological properties of fresh spent mushroom substrates (smss)--without post-crop heat treatment--from agaricus subrufescens and lentinula edodes production to optimize the use of these residues in the soil enrichment for lettuce growth promotion and soil remediation. organic matter and c content of both smss were high. fresh a. subrufescens sms was a good source of n, p and k. on the other hand, l. edodes sms presented a lower concentration o ... | 2009 | 19467593 |
| arsenate toxicity for wheat and lettuce in six chinese soils with different properties. | to assess soil arsenic (as, in the form of arsenate) toxicity to plants, 6-d root elongation tests on wheat (triticum aestivum l.) and lettuce (lactuca sativa) were conducted in six chinese soils freshly spiked with as. plants were treated with 7 or 10 levels of as to establish concentration-effect curves. median effective concentration and 10% effective concentration values were derived with regression analysis to measure as toxic potencies, and no-observed-effect concentration was determined b ... | 2009 | 19379017 |
| moderate and high doses of sodium hypochlorite, neutral electrolyzed oxidizing water, peroxyacetic acid, and gaseous chlorine dioxide did not affect the nutritional and sensory qualities of fresh-cut iceberg lettuce (lactuca sativa var. capitata l.) after washing. | besides the traditionally used sodium hypochlorite (20 and 200 mg l(-1)), alternative sanitizers such as peroxyacetic acid (80 and 250 mg l(-1)) and neutral electrolyzed oxidizing water (4.5 and 30 mg l(-1) free chlorine) as well as chlorine dioxide gas (1.54 mg l(-1)) were evaluated for their efficiency in reducing the microbial load of fresh-cut iceberg lettuce. an additional rinsing step with tap water and cooling of the sanitizing solutions, which are obvious for the fresh-cut industry, were ... | 2009 | 19371140 |
| comprehensive proteome analysis of lettuce latex using multidimensional protein-identification technology. | commercially, lettuce (lactuca sativa) is one of the most important leafy vegetables. lettuce produces a milky latex of variable chemical compositions within its laticifers. as a step toward understanding the main physiological roles of this latex in higher plants, we embarked on its proteomic analysis. we investigated 587 latex proteins that were identified from the lettuce latex using multidimensional protein-identification technology. a bioinformatics analysis showed that the most frequently ... | 2009 | 19356777 |
| phytotoxic aromatic constituents of oxalis pes-caprae. | a cinnamic acid ester, two dihydrocinnamic acid esters, a noroxyneolignan, a dibenzyl ether derivative, along with common aromatic compounds and flavonoids were isolated from the extracts of fresh leaves and twigs of oxalis pes-caprae. the structures of these aromatic compounds were elucidated on the basis of spectroscopic analyses, especially 2d-nmr techniques. their effects on the germination and growth of lactuca sativa l. as standard target species have been studied at concentrations ranging ... | 2009 | 19353540 |
| ecological genomics of natural plant populations: the israeli perspective. | the genomic era revolutionized evolutionary population biology. the ecological genomics of the wild progenitors of wheat and barley reviewed here was central in the research program of the institute of evolution, university of haifa, since 1975 ( http://evolution.haifa.ac.il ). we explored the following questions: (1) how much of the genomic and phenomic diversity of wild progenitors of cultivars (wild emmer wheat, triticum dicoccoides, the progenitor of most wheat, plus wild relatives of the ae ... | 2009 | 19347652 |
| bioactive furanoeremophilanes from senecio otites kunze ex dc. | the furanoeremophilanes 6 beta-angeloyloxy-1,10-dehydrofuranoeremophilan-9-one (1), 6 beta-hydroxy-1,10-dehydrofuranoeremophilan-9-one (2) and 6 beta-propionyloxy-1,10-dehydrofuranoeremophilan-9-one (3) were isolated from senecio otites, their structures elucidated by spectral analyses, and their insecticidal and phytotoxic properties evaluated. compounds 1-3 proved to be effective aphid antifeedants against myzus persicae and rhopalosiphum padi and had postingestive negative effects on spodopte ... | 2009 | 19227831 |
| ethylene reduces gas exchange and growth of lettuce plants under hypobaric and normal atmospheric conditions. | elevated levels of ethylene occur in controlled environment agriculture and in spaceflight environments, leading to adverse plant growth and sterility. the objectives of this research were to characterize the influence of ethylene on carbon dioxide (co(2)) assimilation (c(a)), dark period respiration (dpr) and growth of lettuce (lactuca sativa l. cv. buttercrunch) under ambient and low total pressure conditions. lettuce plants were grown under variable total gas pressures of 25 kpa (hypobaric) a ... | 2009 | 19175518 |
| chlorogenic acid facilitates root hair formation in lettuce seedlings. | root hairs, which arise from root epidermal cells, are tubular structures that increase the efficiency of water absorption and nutrient uptake. a low ph (ph 4) medium induced root hair formation in lettuce (lactuca sativa l.) seedlings, and the decapitation of shoots inhibited root hair formation. the addition of shoot extract to the medium restored root hair formation in the decapitated lettuce seedlings. these results suggest that factors essential to the formation of root hairs may be present ... | 2009 | 19168456 |
| microsatellite instability in lactuca sativa chronically exposed to cadmium. | cadmium (cd) is a cytotoxic, mutagenic and carcinogenic metal. mutagenesis is indicative of genetic instability and can be assayed by use of microsatellite markers (simple sequence repeats, ssrs). these are tandem-repeated tracts of dna composed of units that are 1-6 base pairs (bp) long, spread throughout the genome and highly polymorphic. ssrs can be used in the detection of genomic dna damage and/or mutational events (e.g. deletions, insertions, point mutations). in order to study chronic exp ... | 2009 | 19041419 |
| oil palm waste and synthetic zeolite: an alternative soil-less growth substrate for lettuce production as a waste management practice. | a study was conducted to assess the characteristics and the prospective utilization of oil palm waste (op) and synthetic zeolite (sz) developed by coal fly ash, as an alternative substrate to peat and commercial perlite for lettuce (lactuca sativa l.) production. the sz, op, sphagnum peat (pe), perlite (pl) and two different sz-op mixtures (v/v) at the ratio of 1 : 3 and 1 : 10 were utilized as the substrates under this study. the substrates formulated by mixing sz with op at the ratio of 1 : 3 ... | 2008 | 19039073 |
| phenyl cinnamate derivatives from oxalis pes-caprae. | during the screening of mediterranean invasive plants, oxalis pes-caprae was identified as promising species. the fresh leaves and twigs of the plant were crumbled and extracted with acoet. the solution was concentrated, and separated into acidic and neutral fractions. the crude neutral residue was fractionated by chromatographic procedures, followed by structure elucidation on the basis of 1h- and 13c-nmr, and ms data analysis, and six new phenyl cinnamate derivatives were identified. the phyto ... | 2008 | 19035569 |
| unusual products of the aqueous chlorination of atenolol. | the reaction of the drug atenolol with hypochlorite under conditions that simulate wastewater disinfection was investigated. the pharmaceutical reacted in 1h yielding three products that were separated by chromatographic techniques and characterized by spectroscopic features. two unusual products 2-(4-(3-(chloro(2-chloropropan-2-yl)amino)-2-hydroxypropoxy)phenyl) acetamide and 2-(4-(3-formamido-2-hydroxypropoxy)phenyl) acetamide were obtained along with 2-(4-hydroxyphenyl) acetamide. when the re ... | 2009 | 18996563 |
| quantitative trait loci associated with lettuce seed germination under different temperature and light environments. | temperature and light are primary environmental cues affecting seed germination. to elucidate the genetic architecture underlying lettuce (lactuca sativa l.) seed germination under different environmental conditions, an f8 recombinant inbred line population consisting of 131 families was phenotyped for final germination and germination rate. seeds were imbibed in water at 20 degrees c under continuous red light (20-rc), 20 degrees c continuous dark (20-dc), 31.5 degrees c continuous red light (3 ... | 2008 | 18956026 |
| assessment of biomarkers of cadmium stress in lettuce. | laboratory and field studies have provided encouraging insights into the capacity of plants to act as biomonitors of environmental quality through the use of biomarkers. however, a better understanding of the overall process of cd-induced senescence, describing the cascade of cd effects in plants is needed for a selection of relevant biomarkers of cd stress. in order to approach this, 5-week old lactuca sativa l. were exposed for 14 days to 100mum cd(no(3))(2) and harvested at days 0, 1, 3, 7 an ... | 2009 | 18952284 |
| tributyltin and triphenyltin uptake by lettuce. | this paper provides quantitative information on the transfer of tbt (tributyltin) and tpht (triphenyltin) from sludged soil to cultivated lettuce. the effect of their initial concentrations in the soil (varying from 20 to 50 microg(sn)kg(-1) for each triorganotin), sludge amount (between 1% and 9%), and cultivation duration (32-54 days) was evaluated by means of experimental designs. the impact of the cultivation temperature at 13 degrees c and 19 degrees c on organotin fate in the soil/plant sy ... | 2009 | 18951698 |
| role of syrphid larvae and other predators in suppressing aphid infestations in organic lettuce on california's central coast. | organic lettuce, lactuca sativa l., growers on the central coast of california rely on conservation biological control to manage nasonovia ribisnigri mosley (hemiptera: aphididae) and other aphid pests of lettuce. in 2006, we carried out five replicated field trials to determine the importance of syrphid larvae in the suppression of n. ribisnigri and other aphids infesting organic romaine lettuce. we used entrust, a spinosad-based insecticide approved for use on organic farms, to suppress syrphi ... | 2008 | 18950033 |
| phytotoxic effects of leukamenin e (an ent-kaurene diterpenoid) on root growth and root hair development in lactuca sativa l. seedlings. | leukamenin e, an ent-kaurene diterpenoid isolated from isodon racemosa (hemsl) hara, showed phytotoxic effects on root growth and root hair development of lettuce seedlings (lactuca sativa l.). lower concentrations (10 microm) of leukamenin e did not affect root growth, but at concentrations higher than 50 microm, the rate was inhibited. the influence of leukamenin e on root growth rate was closely correlated with alterations in the mitotic index. a low incidence of aberrant mitosis image was ob ... | 2008 | 18937011 |
| chemical characterization of new oxylipins from cestrum parqui, and their effects on seed germination and early seedling growth. | isolation, chemical characterization, and phytotoxicity of five new oxylipins, together with seven already known related compounds, from cestrum parqui l' hérl. is reported. all the structures were elucidated on the basis of their spectral data, especially 1d-(1h- and 13c-nmr, dept) and 2d-nmr (cosy, tocsy, hsqc, hmbc, and noesy). the configurations of the stereogenic c-atoms were determined by the mosher's method. the compounds have been assayed for their phytotoxicity on lactuca sativa at conc ... | 2008 | 18816534 |
| development of est-ssr markers for the study of population structure in lettuce (lactuca sativa l.). | a set of 61 simple sequence repeat (ssr) markers was developed from the 19,523 lactuca sativa and lactuca serriola unigenes. approximately 4.5% of the unigenes contained a perfect ssr at least 20 bp long, corresponding to roughly 1 perfect ssr per 14.7 kb. marker polymorphism was tested on a set comprising 96 accessions representing all major horticultural types and 3 wild species (l. serriola, lactuca saligna, and lactuca virosa). both the average marker heterozygosity (uhe = 0.32) and the numb ... | 2009 | 18796462 |
| ultraviolet radiation as a limiting factor in leaf expansion and development. | reductions in leaf growth are a commonly observed response to ultraviolet radiation, but the underlying mechanisms remain poorly defined. this study examined the response of leaves exposed to a uv environment across a range of organizational scales, including leaf expansion rate, epidermal cell size and number, biomechanical properties, leaf-water relations and activity of cell-wall peroxidases. two experimental approaches were used; lettuce (lactuca sativa l.) plants were propagated under (a) s ... | 2009 | 18764892 |
| metabolic fate of [14c] chlorophenols in radish (raphanus sativus), lettuce (lactuca sativa), and spinach (spinacia oleracea). | chlorophenols are potentially harmful pollutants that are found in numerous natural and agricultural systems. plants are a sink for xenobiotics, which occur either intentionally or not, as they are unable to eliminate them although they generally metabolize them into less toxic compounds. the metabolic fate of [ (14)c] 4-chlorophenol (4-cp), [ (14)c] 2,4-dichlorophenol (2,4-dcp), and [ (14)c] 2,4,5-trichlorophenol (2,4,5-tcp) was investigated in lettuce, spinach, and radish to locate putative to ... | 2008 | 18763782 |
| genetic variation for lettuce seed thermoinhibition is associated with temperature-sensitive expression of abscisic acid, gibberellin, and ethylene biosynthesis, metabolism, and response genes. | lettuce (lactuca sativa 'salinas') seeds fail to germinate when imbibed at temperatures above 25 degrees c to 30 degrees c (termed thermoinhibition). however, seeds of an accession of lactuca serriola (uc96us23) do not exhibit thermoinhibition up to 37 degrees c in the light. comparative genetics, physiology, and gene expression were analyzed in these genotypes to determine the mechanisms governing the regulation of seed germination by temperature. germination of the two genotypes was differenti ... | 2008 | 18753282 |
| chemical basis for the phytotoxicity of n-aryl hydroxamic acids and acetanilide analogues. | germination inhibition activity of n-aryl hydroxamic acids and acetanilide analogues was measured on lettuce seeds (lactuca sativa). lipophilicity of the compounds was determined by hplc. a correlation between lipophilicity values and percentage of germination inhibition was established. a model mechanism of action for auxin was used for analyzing the effect of the substituent at the alpha carbon atom (ca) on the polarization of hydroxamic and amide functions in relation to the germination inhib ... | 2009 | 18669025 |
| hormesis in mixtures -- can it be predicted? | binary mixture studies are well established for mixtures of pollutants, pesticides, or allelochemicals and sound statistical methods are available to evaluate the results in relation to reference models. the majority of mixture studies are conducted to investigate the effect of one compound on the inhibitory action of another. however, since stimulatory responses to low concentrations of chemicals are gaining increased attention and improved statistical models are available to describe this phen ... | 2008 | 18640701 |
| secondary metabolism and antioxidants are involved in environmental adaptation and stress tolerance in lettuce. | lettuce (lactuca sativa) plants grown in a protective environment, similar to in vitro conditions, were acclimated in a growth chamber and subjected to water stress to examine the activation of genes involved in secondary metabolism and biosynthesis of antioxidants. the expression of phenylalanine ammonia-lyase (pal), gamma-tocopherol methyl transferase (gamma-tmt) and l-galactose dehydrogenase (l-galdh) genes involved in the biosynthesis of phenolic compounds, alpha-tocopherol and ascorbic acid ... | 2009 | 18562042 |
| hybridization rates between lettuce (lactuca sativa) and its wild relative (l. serriola) under field conditions. | hybridization and introgression between crops and wild relatives may have important evolutionary and ecological consequences such as gene swamping or increased invasiveness. in the present study, we investigated hybridization under field conditions between crop lettuce (lactuca sativa) and its wild relative prickly lettuce (l. serriola), two cross-compatible, predominantly autogamous and insect pollinated species. in 2003 and 2004, we estimated the rates of hybridization between l. sativa and l. ... | 2008 | 18549768 |
| antifeedant and phytotoxic activity of the sesquiterpene p-benzoquinone perezone and some of its derivatives. | the sesquiterpene p-benzoquinone perezone (1), isolated from perezia adnata var. alamani (asteraceae), and its non-natural derivatives isoperezone (2), dihydroperezone (3), dihydroisoperezone (4), and anilidoperezone (5) were tested as antifeedants against the herbivorous insects spodoptera littoralis, leptinotarsa decemlineata, and myzus persicae. compounds 1-5 exhibited strong antifeedant activity against l. decemlineata and m. persicae, and elicited a low response by s. littoralis. antifeedan ... | 2008 | 18528728 |