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Lactuca Sativa L. (lactuca + sativa_l)
Selected AbstractsToxicity of methyl tert butyl ether to soil invertebrates (springtails: Folsomia candida, Proisotoma minuta, and Onychiurus folsomi) and lettuce (Lactuca sativa)ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2010Matthew Dodd Abstract Experiments were conducted to assess the toxicity of methyl tert butyl ether (MTBE) to three species of Collembola (Proisotoma minuta, Folsomia candida, and Onychiurus folsomi) and lettuce (Lactuca sativa L.) using an artificial Organization for Economic Cooperation and Development (OECD) soil and field-collected sandy loam and silt loam soil samples. Soil invertebrate tests were carried out in airtight vials to prevent volatilization of MTBE out of the test units and to allow for direct head-space sampling and gas chromatography-mass spectrometry (GC-MS) analysis for residual MTBE. The use of the airtight vial protocol proved to be very successful, in that the measured MTBE concentrations at the beginning of the experiments were within 95% of nominal concentrations. The test methods used in this study could be used to test the toxicity of other volatile organic compounds to Collembola. The soil invertebrates tested had inhibitory concentration (ICx) and lethal concentration (LCx) values that ranged from 242 to 844 mg MTBE/kg dry soil. When the three test species of Collembola were tested under identical conditions in the artificial OECD soil, O. folsomi was the most sensitive collembolan, with a median inhibitory concentration (IC50; reproduction) of 296 mg MTBE/kg dry soil. The most sensitive endpoint for lettuce was an IC50 for root length of 81 mg MTBE/kg dry soil after 5 d of germination in OECD soil. Data on the loss of MTBE from the three test soils over time indicated that MTBE was retained in the silt loam soil longer than in either the sandy loam or the artificial OECD soil. Environ. Toxicol. Chem. 2010;29:338,346. © 2009 SETAC [source] Varietal Differences in Allelopathic Potential of AlfalfaJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 1 2002Tran Dang Xuan Alfalfa (Medicago sativa L.) plants were found to contain water-soluble substances that inhibited the germination and seedling growth of alfalfa (Chung and Miller 1990, Agron. J. 87, 762,767). Tsuzuki et al. (1999, Rep. Kyushu Branch Crop Sci. Soc. Japan 65, 39,40) discovered allelochemicals in alfalfa plants that could have adverse effects on the growth of some lowland weeds. This study was conducted to investigate varietal differences in allelopathic potential in alfalfa plants. Eight common varieties of Japanese alfalfa (Medicago sativa L.), namely Batasu, Hisawakaba, Kitawakaba, Makiwakaba, Natsuwakaba, Lucerne, Tachiwakaba and Yuba, were grown by conventional methods in the Experimental Field of the Crop Science Laboratory, Faculty of Agriculture, Miyazaki University. Aqueous extracts of both fresh and dried material of alfalfa plants of all varieties significantly inhibited both germination and growth of lettuce (Lactuca sativa L.). Leachates from germinating seeds of almost all alfalfa varieties inhibited elongation of the radicle but produced a negligible increase in germination and only slightly inhibited elongation of the hypocotyl of lettuce plants. Results demonstrated that the degree of inhibition of germination and growth of lettuce varied with the variety of alfalfa. In particular, Lucerne was identified as having the strongest allelopathic potential of the varieties studied. The results suggested that the allelopathic potential of alfalfa might be relating to a gene. Varietätsunterschiede im allelopathischen Potential von Luzerne Luzerne (Medicago sativa L.)-Pflanzen weisen wasserlösliche Substanzen auf, die die Keimung und das Sämlingswachstum von Luzerne inhibieren. Es kann angenommen werden, daß Luzernepflanzen allelopathisch wirkende Verbindungen aufweisen, die das Wachstum von Unkrautpflanzen des Tieflands beeinträchtigen. Die Untersuchung wurde durchgeführt, um das Potential allelopathischer Sortenunterschiede bei Luzerne zu bestimmen. Acht im Anbau verwendete Luzernesorten , Batasu, Hisawakaba, Kitawakaba, Makiwakaba, Natsuwakaba, Lucerne, Tachiwakaba und Yuba , wurden nach konventionellen Verfahren auf dem Versuchsfeld des Pflanzenbauinstitutes der Fakultät der Miyazaki-Universität angebaut. Wässerige Extrakte von frischen und trockenen Luzernepflanzen hemmten bei allen Sorten signifikant die Keimung und das Wachstum von Salat (Lactuca sativa L.). Auszüge keimender Samen der meisten Luzernesorten inhibierten das Längenwachstum der Wurzel, hatten aber kaum Einfluß auf eine Förderung der Keimung und zeigten eine geringe Inhibierung des Längenwachstum des Hypokotyls von Salat. Die Ergebnisse zeigen, daß der Grad der Inhibierung der Keimung des Wachstums von Salat abhängig von den geprüften Luzernesorten ist. Lucerne hat das stärkste allelopathische Potential der Sorten. Die Ergebnisse lassen vermuten, daß das allelopathische Potential genetisch bedingt ist. [source] Host Range of Australian Phoma ligulicola var. inoxydablis Isolates from PyrethrumJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2008S. J. Pethybridge Abstract Ray blight, caused by Phoma ligulicola var. inoxydablis is one of the most damaging diseases of pyrethrum (Tanacetum cinerariifolium [Trevir.] Sch. Bip.) in Australia. The pathogenicity of P. ligulicola var. inoxydablis to a range of ornamental and other plant species was tested to determine potential sources of inoculum into pyrethrum crops. Differences were identified in the host range of P. ligulicola var. inoxydablis isolates in this study in comparison with isolates reported from garden chrysanthemum (Chrysanthemum morifolium L.), most likely to be P. ligulicola var. ligulicola. Australian P. ligulicola var. inoxydablis isolates were unable to infect and cause disease following repeated inoculation to zinnia (Zinnia elegans L.), sunflower (Helianthus annuus L.), dahlia (Dahlia variabilis Desf.), and several cultivars of crisphead lettuce (Lactuca sativa L.). French marigold (Tagetes patula L.) was recorded as a susceptible host for this pathogen for the first time. Moreover, the susceptibility of annual chrysanthemum (Chrysanthemum carinatum L.) to infection by P. ligulicola var. inoxydablis was confirmed. Implications for disease management in Tasmanian pyrethrum fields are discussed. [source] Genotype x environment interaction in the uptake of Cs and Sr from soils by plantsJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 1 2004Alexei Melnitchouck Abstract The soil-plant transfer factors for Cs and Sr were analyzed in relationship to soil properties, crops, and varieties of crops. Two crops and two varieties of each crop: lettuce (Lactuca sativa L.), cv. Salad Bowl Green and cv. Lobjoits Green Cos, and radish (Raphanus sativus L.), cv. French Breakfast 3 and cv. Scarlet Globe, were grown on five different soils amended with Cs and Sr to give concentrations of 1 mg kg,1 and 50,mg,kg,1 of each element. Soil-plant transfer coefficients ranged between 0.12,19.10 (Cs) and 1.48,146.10 (Sr) for lettuce and 0.09,13.24 (Cs) and 2.99,93.00 (Sr) for radish. Uptake of Cs and Sr by plants depended on both plant and soil properties. There were significant (P , 0.05) differences between soil-plant transfer factors for each plant type at the two soil concentrations. At each soil concentration about 60,% of the variance in the uptake of the Cs and Sr was due to soil properties. For a given concentration of Cs or Sr in soil, the most important factor effecting soil-plant transfer of these elements was the soil properties rather than the crops or varieties of crops. Therefore, for the varieties considered here, soil-plant transfer of Cs and Sr would be best regulated through the management of soil properties. At each concentration of Cs and Sr, the main soil properties effecting the uptake of Cs and Sr by lettuce and radish were the concentrations of K and Ca, pH and CEC. Together with the concentrations of contaminants in soils, they explained about 80,% of total data variance, and were the best predictors for soil-plant transfer. The different varieties of lettuce and radish gave different responses in soil-plant transfer of Cs and Sr in different soil conditions, i.e. genotype x environment interaction caused about 30,% of the variability in the uptake of Cs and Sr by plants. This means that a plant variety with a low soil-plant transfer of Cs and Sr in one soil could have an increased soil-plant transfer factor in other soils. The broad implications of this work are that in contaminated agricultural lands still used for plant growing, contaminant-excluding crop varieties may not be a reliable method for decreasing contaminant transfer to foodstuffs. Modification of soil properties would be a more reliable technique. This is particularly relevant to agricultural soils in the former USSR still affected by fallout from the Chernobyl disaster. Wechselwirkungen Genotyp x Umwelt im Hinblick auf die Aufnahme von Cs und Sr aus Böden durch Pflanzen Die Transferfaktoren von Cs und Sr vom Boden zur Pflanze wurden in Zusammenhang mit den Bodeneigenschaften, der Fruchtart und der Sorte untersucht. Zwei Fruchtarten mit je zwei Sorten: Salat (Lactua sativa L.) cv. Salad Bowl Green und cv. Lobjoits Green Cos, und Rettich (Raphanus sativus L.) cv. French Breakfast 3 und cv. Scarlet Globe, wurden in fünf verschiedenen Böden, die mit Cs und Sr in Konzentrationen von je 1 mg kg,1 und 50 mg kg,1 angereichert wurden, untersucht. Die Boden-Pflanze-Transferkoeffizienten variierten für Salat von 0,12,19,10 (Cs) und 1,48,146,1 (Sr) und für Rettich von 0,09,13,24 (Cs) und 2,99,93,00 (Sr). Die Aufnahme von Cs und Sr durch Pflanzen hängt sowohl von der Pflanze als auch von den Bodeneigenschaften ab. Es gab signifikante (P , 0,05) Unterschiede zwischen den Boden-Pflanze-Transferfaktoren für jede Pflanzensorte bei beiden Konzentrationen im Boden. Bei jeder Konzentration im Boden wurde die Varianz für die Aufnahme von Cs und Sr zu ca. 60,% von den Bodeneigenschaften bestimmt. Für jede vorgegebene Konzentration von Cs oder Sr im Boden wurde der Boden-Pflanze-Transfer mehr durch die Bodeneigenschaften beeinflusst als durch die Fruchtart oder Sorte. Daher ist der Transfer von Cs und Sr für die hier untersuchten Sorten am besten über eine Beeinflussung der Bodeneigenschaften steuerbar. Die Aufnahme in Rettich und Salat wurde für alle untersuchten Cs- und Sr-Konzentrationen am stärksten durch die K- und Ca-Konzentrationen, den pH-Wert und die KAK der jeweiligen Böden beeinflusst. Die Konzentrationen der Schadstoffe in Böden und die beschriebenen Bodeneigenschaften erklärten ca. 80,% die Gesamtdatenvarianz und sind die besten Voranzeiger für den Boden-Pflanze-Transfer. Die verschiedenen Salat- und Rettichsorten reagierten im Transport von Cs und Sr vom Boden zur Pflanze unterschiedlich auf die verschiedenen Bodeneigenschaften. So erklärte z.,B. die Wechselwirkung Genotyp x Umweltbedingungen ca. 30,% der Variabilität der Pflanzenaufnahme von Cs und Sr. Das bedeutet, dass eine Sorte, die auf einem Boden einen geringen Boden-Pflanze-Transfer von Cs und Sr aufweist, auf einem anderen Boden einen höheren Boden-Pflanze-Transfer aufweisen kann. Die wichtigste Erkenntnis dieser Untersuchung besteht darin, dass die Veränderung der Bodeneigenschaften im Vergleich zum Einsatz von Sorten mit einer geringen Cs- und Sr-Akkumulationsrate auf kontaminierten landwirtschaftlichen Standorten eine aussichtsreichere Methode sein könnte, um die Aufnahme von Cs und Sr in Nahrungsmittel zu minimieren. Diese Aussage ist besonders für landwirtschaftliche Flächen in der früheren UdSSR relevant, die durch die Katastrophe von Chernobyl kontaminiert wurden. [source] 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 cultureJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2010Wim Voogt Abstract BACKGROUND: 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. RESULTS: In both a winter and summer trial, dose rates of 0, 13, 39, 65, and 90 or 129 µg iodine L,1, applied as iodate (IO3,) or iodide (I,), did not affect plant biomass, produce quality or water uptake. Increases in iodine concentration significantly enhanced iodine content in the plant. Iodine contents in plant tissue were up to five times higher with I, than with IO3,. Iodine was mainly distributed to the outer leaves. The highest iodide dose rates in both trials resulted in 653 and 764 µg iodine kg,1 total leaf fresh weight. CONCLUSION: Biofortification of lettuce with iodine is easily applicable in a hydroponic growing system, both with I, and IO3,. I, was more effective than IO3,. Fifty grams of iodine-biofortified lettuce would provide, respectively, 22% and 25% of the recommended daily allowance of iodine for adolescents and adults. Copyright © 2010 Society of Chemical Industry [source] Isolation and identification of a potent allelopathic substance in rice root exudatesPHYSIOLOGIA PLANTARUM, Issue 3 2002Hisashi Kato-Noguchi A search for growth inhibitors in rice root exudates was undertaken in order to clarify the allelopathic system in rice (Oryza sativa L.). Rice seedlings inhibited the growth of cress (Lepidium sativum L.) and lettuce (Lactuca sativa L.) seedlings when the cress and lettuce were grown with rice seedlings. The putative compound causing the inhibitory effect of rice seedlings was isolated from their culture solution, and the chemical structure of the inhibitor was determined by spectral data as momilactone B. Momilactone B inhibited the growth of cress and lettuce seedlings at concentrations greater than 3 and 30 µM, respectively. The concentration of momilactone B was 3.4 and 1.1 nmol per seedling in the culture solutions of husked and non-husked rice seedlings, respectively. These results suggest that rice seedlings may release momilactone B into the environment and the stress caused by the husk-treatment may increase the amount of momilactone B released. Thus, momilactone B may play an important role in rice allelopathy. [source] Carbon use efficiency depends on growth respiration, maintenance respiration, and relative growth rate.PLANT CELL & ENVIRONMENT, Issue 9 2003A case study with lettuce ABSTRACT Carbon use efficiency (CUE, the ratio between the amount of carbon incorporated into dry matter to the amount of carbon fixed in gross photosynthesis) is an important parameter in estimating growth rate from photosynthesis data or models. It previously has been found to be relatively constant among species and under different environmental conditions. Here it is shown that CUE can be expressed as a function of the relative growth rate (rGR) and the growth (gr) and maintenance respiration coefficients (mr): 1/CUE = 1 + gr + mr/rGR. Net daily carbon gain (Cdg), rGR, and CUE were estimated from whole-plant gas exchange measurements on lettuce (Lactuca sativa L.) ranging from 24 to 66 d old. Carbon use efficiency decreased from 0.6 to 0.2 with increasing dry mass, but there was no correlation between CUE and Cdg. The decrease in CUE with increasing dry mass was correlated with a simultaneous decrease in rGR. From the above equation, gr and mr were estimated to be 0.48 mol mol,1 and 0.039 g glucose g,1 dry matter d,1, respectively. Based on the gr estimate, the theoretical upper limit for CUE of these plants was 0.68. The importance of maintenance respiration in the carbon balance of the plants increased with increasing plant size. Maintenance accounted for 25% of total respiration in small plants and 90% in large plants. [source] Structure Elucidation and Phytotoxicity of Ecdysteroids from Chenopodium albumCHEMISTRY & BIODIVERSITY, Issue 4 2005Marina DellaGreca The leaves of Chenopodium album were infused in H2O/MeOH. The extract treated with cold acetone gave heavy precipitation, which was removed by centrifugation. Solid material was fractionated into acidic and neutral fractions. The acidic material was subjected to different silica-gel column chromatographies, and then it was purified by reversed-phase HPLC to afford four known ecdysteroids and the new 3,,14, -dihydroxy-5, -pregn-7-ene-2,6,20-trione that were characterized by extensive spectroscopic investigation, especially by 1D- and 2D-NMR. Their effects on germination and growth of Lactuca sativa L. have been studied. The results are reported as percentage differences of germination, root elongation and shoot elongation, from the control at concentrations ranging from 10,4 to 10,7,M. [source] Chenoalbicin, a Novel Cinnamic Acid Amide Alkaloid from Chenopodium albumCHEMISTRY & BIODIVERSITY, Issue 10 2004Francesca Cutillo The roots of Chenopodium album were infused in MeOH, and the extract was partitioned between AcOEt and H2O. AcOEt-Soluble material was subjected to different silica-gel column chromatographies and then purified by reverse-phase HPLC to afford a new cinnamic acid amide alkaloid as a racemic mixture. The new compound, named chenoalbicin (1), was characterized by extensive spectroscopic investigation, especially 1D and 2D NMR spectroscopy. Its effects on the germination and growth of Lactuca sativa L. has been studied. The results are reported as percentage differences of germination, root elongation, and shoot elongation from the control at concentrations ranging from 10,4 to 10,7,M. [source] | ||||||||||||||||