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Sample records for catenulata sobre zea

  1. A Perilipin Gene from Clonostachys rosea f. Catenulata HL-1-1 Is Related to Sclerotial Parasitism

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    Zhan-Bin Sun

    2015-03-01

    Full Text Available Clonostachys rosea f. catenulata is a promising biocontrol agent against many fungal plant pathogens. To identify mycoparasitism-related genes from C. rosea f. catenulata, a suppression subtractive hybridization (SSH cDNA library of C. rosea f. catenulata HL-1-1 that parasitizes the sclerotia of S. sclerotiorum was constructed. 502 clones were sequenced randomly, and thereby 472 expressed sequence tags (ESTs were identified. Forty-three unigenes were annotated and exhibited similarity to a wide diversity of genes. Quantitative real -time PCR showed that a perilipin-like protein encoding gene, Per3, was up-regulated by 6.6-fold over the control at 96 h under the induction of sclerotia. The full-length sequence of Per3 was obtained via 5' and 3' rapid identification of cDNA ends. Overexpression of Per3 in HL-1-1 significantly enhanced the parasitic ability on sclerotia. The results indicated that Per3 might be involved in the mycoparasitism of C. rosea f. catenulata HL-1-1. This is the first report of a perilipin as a potential biocontrol gene in mycoparasites. The study provides usefu l insights into the interaction between C. rosea f. catenulata and fungal plant pathogens.

  2. Estudio de la irritación ocular y dérmica de Pochonia chlamydosporia var. catenulata

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    L. García

    2004-01-01

    Full Text Available Pochonia chlamydosporia var. catenulata, cepa Vcc 108 es un agente eficaz en el control de Meloidogyne spp. Para determinar el potencial de irritación dérmica y ocular se emplearon los métodos in vivo descritos por la Agencia de Protección Ambiental (EPA y dos ensayos in vitro como alternativos a irritación ocular, el método de la membrana corioalantoidea del huevo de gallina (HET-CAM y el ensayo cuantitativo con tinción de azul de tripán (CAM-TBS. En los estudios in vitro se aplicaron cuatro concentraciones del hongo vivo e inactivado y en los in vivo se emplearon dosis límite. Aunque cada método utiliza diferentes categorías de irritación, en todos los ensayos Pochonia chlamydosporia var. catenulata se clasificó como No irritante dérmico y ocular

  3. Efectividad de filtrados de hongos presentes en frutos de maíz (Zea mays L.) sobre Fusarium moniliforme

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    Reyes, Janeth; Pineda, Juan de (S.I.), 1558-1637; Sanabria., Maria Elena

    2007-01-01

    Los frutos de maíz son portadores de hongos, como el caso de Fusarium moniliforme, que producen micotoxinas, las cuales pueden ser altamente tóxicas, por lo tanto es necesario controlar su presencia en los mismos. El presente trabajo tuvo como objetivo evaluar la efectividad de fi ltrados puros de hongos presentes en frutos de maíz sobre dicho patógeno. De muestras provenientes de localidades de los Estados Lara, Yaracuy y Portuguesa, se obtuvo la micobiota: Aspergillus ni...

  4. Efecto de la aplicación de mezclas de abono organomineral en el cultivo del maíz (Zea mays L. sobre un suelo pardo sialítico mullido no carbonatado.

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    Pável Chaveli Chávez

    2013-04-01

    Full Text Available RESUMEN Se realizó un estudio para comprobar el efecto de varias mezclas de abonos organominerales sobre el cultivo del maíz en un suelo Pardo sialítico mullido no carbonatado. Se utilizaron cinco diferentes mezclas utilizando como abonos orgánicos el estiércol vacuno composteado; cachaza y como portadores minerales urea, superfosfato triple y cloruro de potasio. Además se tomaron muestras de suelo con el objetivo de medir el efecto que produce la utilización de este abono sobre las principales propiedades del mismo. Se obtuvo que la fertilización organomineral favorece la producción de maíz, manteniendo el rendimiento y la calidad del fruto con respecto a la fertilización mineral tradicional; de igual forma no deteriora las condiciones del suelo para el mejor desarrollo del cultivo. EFFECT OF FERTILIZER APPLICATION OF MIXED ORGANOMINERAL GROWING CORN (Zea mays ON BROWN SIALYTIC FLUFFY NONCARBONATED SOIL. ABSTRACT. A study was conducted to test the effect of various mixtures of organo-fertilizers on maize in a fluffy Sialytic Brown noncarbonated soil. Five different mixtures were used as organic fertilizers using the composted cow manure, press mud as carrier minerals and urea, triple superphosphate and potassium chloride. In addition soil samples were taken in order to measure the effect of the use of this fertilizer on major properties. It was found that the organo-fertilization favors the production of corn, maintaining performance and fruit quality compared to traditional mineral fertilization, and likewise does not deteriorate the soil conditions for better crop development.

  5. Efectos de extractos acuosos de la maleza Cyperus rotundus L. (Cyperaceae sobre la germinación de semillas y crecimiento de plántulas de maíz ( Zea mays L. cv. Pioneer 3031

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    José A. Laynez Garsaball

    2013-04-01

    Full Text Available La investigación tuvo por fi nalidad determinar los efectos de extractos acuosos del follaje de Cyperus rotundus L. sobre la germinación de semillas y el crecimiento de plántulas de maíz ( Zea mays L. cv. Pioneer 3031. Un primer extracto al 15% p/v fue preparado con el follaje de plantas mays L. cv . Pioneer 3031. Un primer extracto al 15% p/v fue preparado con el follaje de plantas mays de C. rotundus de 15 días, se dejó reposar por 48 h y luego se obtuvo por dilución extractos al 0; 2,0; 4,0 y 6,0% p/v evaluándoseles pH y conductividad eléctrica (S.cm -1 . Para la siembra se utilizaron bandejas cubiertas con una doble capa de papel absorbente sobre la que se colocó 20 semillas/bandeja, tapadas con dos hojas más de papel y regadas tres veces al día con los extrac- tos foliares. El tratamiento control recibió agua corriente. El diseño estadístico fue bloques al azar con cuatro concentraciones de extracto y cinco repeticiones. A los 12 días después de la siembra se determinaron los diferentes parámetros de germinación y crecimiento. Se práctico un análisis de varianza y regresión para los parámetros estudiados. El pH disminuyó y la CE incrementó al aumentar la concentración del extracto. La germinación, altura de las plántulas, longitud de las radículas, peso seco del vástago y relación peso seco del vástago/peso seco de la radícula dismi- nuyeron proporcionalmente al aumento de la concentración de extracto, contrariamente, el peso seco de la radícula incrementó. La relación altura de la plántula/longitud de la radícula no presentó diferencias signifi cativas en las fuentes de variación.

  6. EFFECT OF DIFFERENT MULCHES ON THE CONTROL OF UNWISHED PLANTS IN MAIZE CROP (Zea mays EFEITO DE DIVERSAS ESPÉCIES DE COBERTURA MORTA SOBRE O CONTROLE DE PLANTAS DANINHAS DA CULTURA DO MILHO

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    Rogério de Araújo Almeida

    2007-09-01

    ;">KEY-WORDS: Mulches; uwished plants; maize crop.

    Pesquisas em diversos países sul-americanos apontam o plantio direto para pequenos produtores como responsável por melhor conservação do solo e água, menores custos de produção e maiores rendimentos, melhorando o nível de vida dos produtores e propiciando sua permanência no meio rural. Os tratamentos normalmente incluem a aplicação de herbicidas e considera-se um desafio à pesquisa encontrar sistemas que viabilizem o plantio direto sem uso, ou com uso reduzido, de herbicidas. Objetivando avaliar os efeitos de diferentes coberturas mortas sobre o controle de plantas indesejáveis na cultura do milho (Zea mays, conduziu-se o presente trabalho, cujos tratamentos foram constituídos pelo cultivo de áreas de cem metros quadrados com as seguintes plantas: crotalária (Crotalaria juncea, milheto (Pennisetum americanum e girassol (Helianthus annus L., cultivares Stanzuela e V 2000. A semeadura foi efetuada na segunda quinzena do mês de abril e, decorridos sessenta dias, foi feito o plantio direto do milho, com matraca. Imediatamente após, as plantas constantes nas parcelas foram cortadas manualmente, constituindo-se em cobertura morta. Fez-se adubação de acordo com a análise do solo e a população adotada foi de 60.000 plantas por hectare. Não houve controle de plantas daninhas. Por ocasião do florescimento do milho, coletaram-se as plantas daninhas presentes nas parcelas, mediante amostragens de 1 m² (duas repetições. O material foi seco até peso constante. A análise estat

  7. EFECTO DE LOS EXTRACTOS ETANÓLICOS DE ZEA MAYS L. Y DE BETA VULGARIS SOBRE EL PERFIL LIPIDICO EN RATAS NORVERGICUS WISTAR HIPERCOLESTEROLEMICAS. BIOTERIO U.C.S.M. AREQUIPA 2015

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    HERRERA ENRÍQUEZ, PAMELA CATHERINE

    2016-01-01

    LIPIDOGRAMA COLESTEROL FUNCIONES DEL COLESTEROL TRANSPORTE DEL COLESTEROL EXCRECIÓN DEL COLESTEROL DETERMINACIÓN DEL COLESTEROL TOTAL (SUERO-PLASMA) LIPOPROTEÍNAS TIPOS DE LIPOPROTEÍNAS TRIGLICÉRIDOS SÍNTESIS DE TRIGLICÉRIDOS TRANSPORTE DE TRIGLICÉRIDOS DETERMINACIÓN DE TRIGLICÉRIDOS ALTERACIONES DEL PERFIL LIPÍDICO DISLIPIDEMIA RIESGO CARDIOVASCULAR GLOBAL (RCG) HIPERCOLESTEROLEMIA HIPERTRIGLICERIDEMIA ATEROSCLEROSIS TRATAMIENTO DISLIPIDEMIAS FARMACOLÓGICO NO FARMACOLÓGICO MAÍZ MORADO- ZEA M...

  8. Efeito do tamanho de partícula e da altura de colheita das plantas de milho (Zea mays L. sobre as perdas durante o processo fermentativo e o período de utilização das silagens Effect of particle size and cutting height of corn (Zea mays L. on losses of silages during the fermentation process and utilization period

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    Mikael Neumann

    2007-10-01

    Full Text Available O experimento foi conduzido com o objetivo de avaliar o efeito do tamanho de partícula (pequena de 0,2 a 0,6 cm ou grande de 1,0 a 2,0 cm e da altura de corte das plantas de milho para ensilagem (baixo: 15,2 cm ou alto: 38,6 cm sobre as perdas e o valor nutritivo das silagens. Foram avaliadas as seguintes silagens: silagem de partícula pequena com altura de corte baixo; silagem de partícula grande com altura de corte baixo; silagem de partícula pequena com altura de corte alto; e silagem de partícula grande com altura de corte alto. Não houve efeito significativo das interações altura de colheita das plantas × tamanho de partícula sobre as perdas de MS, PB e FDN. Influências significativas das interações altura de colheita das plantas × estrato no silo e tamanho de partícula × estrato no silo foram observadas, respectivamente, sobre as perdas de MS e PB. As silagens obtidas com corte alto (38,6 cm no estrato inferior apresentaram maiores perdas (4,91% em relação ao estrato superior no silo (2,67% e às silagens obtidas com corte baixo (15,2 cm, independentemente do estrato no silo. Na análise das perdas de PB, os maiores valores foram observados em silagens de partículas pequenas no estrato superior (18,96% e em silagens de partículas grandes no estrato inferior (18,68%, comparativamente às silagens com partículas pequenas no estrato inferior (11,52% e às silagens de partículas grandes no estrato superior (17,54%. A silagem com partícula grande resultou em maiores perdas físicas na desensilagem.This trial evaluated the effect of particle size (small: between 0.2 and 0.6 cm or large: between 1.0 and 2.0 cm and cutting height (low cut: 15.2 cm or high cut: 38.6 cm of the corn plant on losses and nutritional value of silages. Treatments were: T1 - small particle size with low cutting height; T2 - large particle size with low cutting height; T3 - small particle size with high cutting height; and T4 - large particle size

  9. "Zea"-Because It's There

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    Chamberlain, Eric

    1983-03-01

    The Subject is a long standing symbiotic relationship between Zea and the movies. As usual the impossible was required - to attain cinema release quality films with dramatic interpretation - at the same time using Hy-speed macro photographic techniques. The subject was not to be recognizable until the end of the film - some four minutes long. Zea is explosive, it reacts to heat and is extremely difficult to predict when it will explode, which left little time for the focus, stop down and shooting. Using a Hy-cam at 5,000 pictures per second - a 400 ft. roll of 7247 raw stock, left but a brief three seconds for synchronization. To add to the confusion, two co-directors, a cameraman, plus equipment, were jammed into a 2 x 2m space. To achieve reasonable resolution for theatrical showing, 400,000 foot/candles of light were needed. This was achieved. The film was edited and music from Vaughan Williams' "Fantasia" recorded at St. Martins-in-the-Fields, London was added. The result was sent to the Cannes Film Festival, where it was given the Jury Award.

  10. ZEA MAIZE: A MODERN CRAZE

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    Dhamija Isha

    2013-06-01

    Full Text Available Zea stands for ‘sustaining life’ and Mays stands for ‘life giver’. Zea mays is one of the oldest and most dynamic crop species, which has gained popularity in modern world too, due to its applications in diverse dishes. Corn is produced in every continent of the world with the exception of Antarctica. It is an annual monoecious sunny plant, surviving perfectly in nutrient rich, well-drained soil. Each and every part of the corn, from husk to corn silk is beneficial for the society. There are more than 3,500 different uses for corn products. Corn does much more than feed people and livestock. The plant contains alkaloids, flavonoids, saponins, maizenic acid, vitamins B1, K and minerals like potassium, phosphorous and zinc. Traditionally, Maize is used as an analgesic, anti-diarrheal, anti-prostatitic, anti-lithiasis, anti-tumor, anti-hypertensive, anti-diabetic, anti-hyperlipidemic, anti-inflammatory and anti-oxidant. In this review article, we have narrated miscellaneous uses of corn varieties and described the pharmacological activities, phytoconstituents, nutritional value and traditional uses of maize. The maize has assorted uses like culinary, medicinal and industrial. Corn dishes like corn-meal, corn-flakes, popcorn, “makki ki roti” and corn soup highlight its dominance all over the world. Therefore, maize has become a craze among modern youth.

  11. Maize, tropical (Zea mays L.).

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    Assem, Shireen K

    2015-01-01

    Maize (Zea mays L.) is the third most important food crop globally after wheat and rice. In sub-Saharan Africa, tropical maize has traditionally been the main staple of the diet; 95 % of the maize grown is consumed directly as human food and as an important source of income for the resource-poor rural population. The biotechnological approach to engineer biotic and abiotic traits implies the availability of an efficient plant transformation method. The production of genetically transformed plants depends both on the ability to integrate foreign genes into target cells and the efficiency with which plants are regenerated. Maize transformation and regeneration through immature embryo culture is the most efficient system to regenerate normal transgenic plants. However, this system is highly genotype dependent. Genotypes adapted to tropic areas are difficult to regenerate. Therefore, transformation methods used with model genotypes adapted to temperate areas are not necessarily efficient with tropical lines. Agrobacterium-mediated transformation is the method of choice since it has been first achieved in 1996. In this report, we describe a transformation method used successfully with several tropical maize lines. All the steps of transformation and regeneration are described in details. This protocol can be used with a wide variety of tropical lines. However, some modifications may be needed with recalcitrant lines.

  12. Teosinte inflorescence phytolith assemblages mirror Zea taxonomy.

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    John P Hart

    Full Text Available Molecular DNA analyses of the New World grass (Poaceae genus Zea, comprising five species, has resolved taxonomic issues including the most likely teosinte progenitor (Zea mays ssp. parviglumis of maize (Zea mays ssp. mays. However, archaeologically, little is known about the use of teosinte by humans both prior to and after the domestication of maize. One potential line of evidence to explore these relationships is opaline phytoliths produced in teosinte fruit cases. Here we use multidimensional scaling and multiple discriminant analyses to determine if rondel phytolith assemblages from teosinte fruitcases reflect teosinte taxonomy. Our results indicate that rondel phytolith assemblages from the various taxa, including subspecies, can be statistically discriminated. This indicates that it will be possible to investigate the archaeological histories of teosinte use pending the recovery of appropriate samples.

  13. Una filosofía para América Latina: Leopoldo Zea

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    Giuseppe Cacciatore

    2004-01-01

    Full Text Available Uno de los mas significativos recorrido filosoficos e hsitorico-culturales a traves de los que se ha manisfestado la reflexion sobre la identidad latinoamericana es indudablemente el trazado por el pensador mexicano Leopoldo Zea, alumno predilecto de jose gaos. En el, como en tanto otros intelectuales de los paises latinos del conteniente americano el problema de la individuacion de las trazas de una autonoma dimension filosofica (y de su ambivalente relacion con la tradicion indigena pre-colonial y con los modelos de la cultura europea se liga constante y significativamente al evento traumatico y dramatico de la conquista y del genocidio. Zea no se cierra en esta dicatomia civilizacion precolombina/civilizacion europea, ni olvida la que quizas es la verdadera especificidad del continente americano centromeridional, la multiculturalidad y la multietnia, el denominado mestizaje.

  14. Urinary deoxynivalenol (DON) and zearalenone (ZEA) as biomarkers of DON and ZEA exposure of pigs.

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    Thanner, S; Czeglédi, L; Schwartz-Zimmermann, H E; Berthiller, F; Gutzwiller, A

    2016-05-01

    Four diets contaminated with 1.1 to 5.0 mg/kg deoxynivalenol (DON) and 0.4 to 2.4 mg/kg zearalenone (ZEA) were fed to four groups of six growing Large White pigs. Urine samples were collected after 3 to 4 days and again after 6 to 7 days on the diets. On each sampling day, half of the animals were sampled in the morning, after an 8-h fast, and the other half were sampled in the afternoon, after 7 h of ad libitum access to feed. The urinary concentrations of DON, DON-glucuronide, DON-3-sulphate, de-epoxy-DON, as well as of ZEA, ZEA-14-glucuronide, α-zearalenol and α-zearalenol-14-glucuronide, analysed using LC-MS/MS, were used to calculate urinary DON and ZEA equivalent concentrations (DONe and ZEAe). The urinary concentration of DONe (P < 0.001), but not of ZEAe (P = 0.31), was lower in the fasted than that in the fed animals. The urinary DONe/creatinine and ZEAe/creatinine ratios were highly correlated with DON and ZEA intake per kg body weight the day preceding sampling (r = 0.76 and 0.77; P < 0.001). The correlations between DON intake during the 7 h preceding urine sampling in the afternoon and urinary DONe/creatinine ratio (r = 0.88) as well as between mean ZEA intake during 3 days preceding urine sampling and urinary ZEAe/creatinine ratio (r = 0.84) were even higher, reflecting the plasma elimination half-time of several hours for DON and of more than 3 days for ZEA. ZEAe analysed in enzymatically hydrolysed urine using an ELISA kit was highly correlated with the LC-MS/MS data (r = 0.94). The urinary DONe and ZEAe to creatinine ratios, analysed in pooled urine samples of several pigs fed the same diet, can be used to estimate their exposure to DON and ZEA.

  15. Glucolipids of Zea mays and Pisum sativum

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    Morohashi, Y.; Bandurski, R.S.

    1976-06-01

    The glucolipids formed upon feeding (U--/sup 14/C)glucose to embryos of Zea mays were partially characterized with respect to: (a) metabolic turnover, (b) acid lability, (c) phosphorus content, (d) chromatographic properties, and (e) hydrolysis products. The chloroform--methanol-soluble-assimilated radioactivity was examined specifically for occurrence of a glycosylated prenol phosphate. With the extraction conditions used, no evidence was found for formation of a glucosylated prenol phosphate. Several, as yet unidentified, acid-labile glucolipids undergoing metabolic turnover were observed. Four diglycerides were characterized as hydrolysis products of a fraction that contained /sup 14/C-glucose and phosphorus, and was subject to metabolic turnover. Examination of the 1-butanol-soluble glucolipids from pea (Pisum sativum) seedlings also demonstrated anionic glucolipids, evidencing metabolic turnover but none with the properties of glucosylated prenol phosphate.

  16. Efecto del herbizida Antrazina sobre los microorganismos Diazótrofos asociados al cultivo de maíz ( Zea mays L. en un suelo de Saldaña (Tolima Effect of atrazine on the diaztrophos associated with corn cultivated on soil from Saldana, Tolima

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    Ordoñez Alba Ruth

    1999-11-01

    Full Text Available

    En un experimento de invernadero, se evaluó el efecto a través del tiempo de la aplicación del herbicida atrazina sobre la población de microorganisrnos diazótrofos asociados a raíz y suelo rizosférico de un cultivo de maíz en un suelo, Uscroper Fluvaquentic, franco-arcillo-arenoso de Saldaña (Tolima. El 61% de los aislamientos de suelo y el 83% de los de raíz presentaron crecimiento característico en forma de película blanquecina bajo la superficie del medio. La población de microorganismos diazótrofos de suelo rizosférico y la actividad de la nitrogenasa no presentaron diferencias significativas por la aplicación del herbicida. Los mayores valores en la actividad de la nitrogenasa se presentaron a los 45 días de aplicación del herbicida con la dosis más alta (3,0 Kg/ha. En las raíces de maíz, el testigo sin aplicación de atrazina presentó los valores más altos, sin embargo, tampoco en este caso se presentaron diferencias significativas entre las dosis ni a claves del tiempo. Se concluye que bajo las condiciones del experimento, hasta los 90 días, no se presentó efecto significativo de la aplicación de atrazina sobre la actividad ni sobre la población de diazotrofos presentes en la rizosfera y en la raíz de las plantas de maíz.

    The effect of the herbicide atrazine on the diazotrophic microorganisms associated with rhizosphere soil and roots of a corn cultivated on a clay-loam soil in a greenhouse, Ustropet Fluvaquentic from Saldana (Tolima was evaluated. 61% of soil isolates and 83% of root isolates presented characteristic cultural growth of whitish pellicle under the surface of the semisolid NFb-malic acid medium. The soil population of diazotrophic microorganisms and the nitrogenase activity were not significantly different between atrazine treatments. The highest values were obtained 45 days after the highest dose ofatrazine (3.0 Kg/ha. Corn roots without treatment had greater values

  17. Maíz I (Zea mays)

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    Sánchez Ortega, Iván; Pérez-Urria Carril, Elena

    2014-01-01

    El maíz es uno de los cultivos básicos más importantes y extendidos en todo el mundo. Constituye una de las fuentes principales de alimento de millones depersonas, sobre todo en América y Asia. Se trata de una de las primeras plantas que se domesticaron y se difundieron por todo el mundo.

  18. Caracterización de los ácidos húmicos extraídos de cuatro lombricompuestos y su efecto sobre la germinación de semillas de maíz Zea mays L., algodón Gossypium hirsutum y tomate Lycopersicon esculentum L.

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    Gómez Zambrano Jairo

    1996-12-01

    Full Text Available

    The work perfomed to characterize the elemental composition and functional groups of humic acids extracted from four lombricompost cow dung, filter press cake of sugar cane, coffee pulp and grass residue the total content of essential elements and its distribution in the humic and no humic fractions were determined. It was evalued the effect of two concentrations of humic acids (150 and 300 ppm upon seed germination of maize, cotton and tomat. There were found differences in the elemental composition (CHON and functional groups (COOH, OH phedic and carbony of the humic acids atributed to variations in composition of the original substrates. The lombricompost of cow dung showed higher oxidation values (O/H = 0.49 than the lombricompost of filter press cake of sugar cane (0.40 sugering a higher grade of humification of the first. The grass residue showed higher contribution to the CIC (COOH + OH = 9. O me/g than the coffe pulp (7. 1 me/g the total essential elements were concentrated in the remanent residue, with lower content in the water and 0.1M HCL solutions; the fulvic and humic fractions had very low content of these elements. The humic acid at the concentrations tested did not have any effect on the germination of maize and cotton, and depressed the germination of tomato seeds.

    El trabajo se realizó con el fin de caracterizar por su composición elemental y contenido de grupos funcionales, los acidos húmicos extraídos de cuatro lombricompuestos (bovinaza, cachaza, pulpa de café y residuo de prado. Se determinó el contenido y distribución de los elementos esenciales totales en las fracciones húmicas y no de acidos húmicas. Se evaluó el efecto de dos concentraciones de acidos húmicos (150 y 300 ppm sobre la germinación de semillas de maíz, algodón y tomate. Se encontraron diferencias en el contenido elemental (CHON y grupos funcionales (COOH, OH fenólico y carbonilo atribuido a variaciones en la composición de los

  19. Induced cytomictic diversity in maize (Zea mays L.) inbred.

    Science.gov (United States)

    Rai, Prashant Kumar; Kumar, Girjesh; Tripathi, Avinash

    2010-01-01

    Mutation breeding has been used for improving oligogenic and polygenic characters, disease resistance and quantitative characters including yielding ability. The cytological stability of maize inbred lines is an important consideration in view of their extensive use in genetics and plant breeding research. Investigation in Zea mays L. confirms that the migration of chromosomes is a real event that cannot be misunderstood as an artifact produced by fixation or mechanical injuries. During present investigation, we found that out of six inbred lines of Zea mays L. viz. CM-135, CM-136, CM-137, CM-138, CM-142 and CM-213 at various treatment doses of gamma irradiations viz. 200, 400 and 600 Gy, some of the plants of inbred line CM- 138 at 200 Gy dose displayed characteristic cytoplasmic connections during all the stages of meiosis. Four plants from this treatment set were found to be engaged in a rare phenomenon reported as "Cytomixis". It elucidates that in inbred of Zea mays L., induced cytomixis through gamma rays treatment may be considered to be a possible source of production of aneuploid and polyploid gametes. This phenomenon may have several applications in Zea mays L. improvement in the sense of diversity and ever yield potential.

  20. Pinitol, a larval growth inhibitor for Heliothis zea in soybeans.

    Science.gov (United States)

    Dreyer, D L; Binder, R G; Chan, B G; Waiss, A C; Hartwig, E E; Beland, G L

    1979-09-15

    A search for insect growth inhibitors in methanol extracts of soybean leaves resulted in isolation of pinitol. Pinitol caused a 50% reduction in weight gain (ED50) of Heliothis zea larvae at about 0.7% when added to a synthetic diet. Although myo-inositol is a normal component of the insect diet, it also caused growth inhibition at higher concentrations; ED50 4%.

  1. PATOGENICIDAD BACTERIANA EN MAÍZ (ZEA MAYS)

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    Rocío Pérez-y-Terrón; Julio César Carmona Díaz; Jorge Alejandro Cebada Ruíz; José Antonio Munive Hernández

    2012-01-01

    El maíz es un grano de consumo mundial para alimento tanto humano como animal. México se encuentra en el séptimo lugar de la producción, China y Estados Unidos son los principales consumidores. Zea mays pertenece a la familia de las gramíneas y tiene producción anual. La planta se puede ver afectada por plagas principalmente de diferentes especies de insectos. Puede también desarrollar enfermedad debida a hongos y virus, así como a bacterias patogénicas. Dentro de estas la causada por organis...

  2. Structure of the novel monomeric glyoxalase I from Zea mays.

    Science.gov (United States)

    Turra, Gino L; Agostini, Romina B; Fauguel, Carolina M; Presello, Daniel A; Andreo, Carlos S; González, Javier M; Campos-Bermudez, Valeria A

    2015-10-01

    The glyoxalase system is ubiquitous among all forms of life owing to its central role in relieving the cell from the accumulation of methylglyoxal, a toxic metabolic byproduct. In higher plants, this system is upregulated under diverse metabolic stress conditions, such as in the defence response to infection by pathogenic microorganisms. Despite their proven fundamental role in metabolic stresses, plant glyoxalases have been poorly studied. In this work, glyoxalase I from Zea mays has been characterized both biochemically and structurally, thus reporting the first atomic model of a glyoxalase I available from plants. The results indicate that this enzyme comprises a single polypeptide with two structurally similar domains, giving rise to two lateral concavities, one of which harbours a functional nickel(II)-binding active site. The putative function of the remaining cryptic active site remains to be determined.

  3. Mutational effects of space flight on Zea mays seeds

    Science.gov (United States)

    Mei, M.; Qiu, Y.; He, Y.; Bucker, H.; Yang, C. H.

    1994-01-01

    The growth and development of more than 500 Zea mays seeds flown on Long Duration Exposure Facility (LDEF) were studied. Somatic mutations, including white-yellow stripes on leaves, dwarfing, change of leaf sheath color or seedling color were observed in plants developed from these seeds. When the frequency of white-yellow formation was used as the endpoint and compared with data from ground based studies, the dose to which maize seeds might be exposed during the flight was estimated to be equivalent to 635 cGy of gamma rays. Seeds from one particular holder gave a high mutation frequency and a wide mutation spectrum. White-yellow stripes on leaves were also found in some of the inbred progenies from plants displayed somatic mutation. Electron microscopy studies showed that the damage of chloroplast development in the white-yellow stripe on leaves was similar between seeds flown on LDEF and that irradiated by accelerated heavy ions on ground.

  4. PATOGENICIDAD BACTERIANA EN MAÍZ (ZEA MAYS

    Directory of Open Access Journals (Sweden)

    Rocío Pérez-y-Terrón

    2012-01-01

    Full Text Available El maíz es un grano de consumo mundial para alimento tanto humano como animal. México se encuentra en el séptimo lugar de la producción, China y Estados Unidos son los principales consumidores. Zea mays pertenece a la familia de las gramíneas y tiene producción anual. La planta se puede ver afectada por plagas principalmente de diferentes especies de insectos. Puede también desarrollar enfermedad debida a hongos y virus, así como a bacterias patogénicas. Dentro de estas la causada por organismos del género Pantoea. P. stewartii se sabe que tiene genes como cps que codifican para la producción de exopolisacarido sterwatan controlada por un mecanismo de quórum sensing, y hrp para el sistema de secreción tipo III involucrados en la patogenicidad de la bacteria.

  5. Plasmid-mediated Detoxification of Mycotoxin Zearalenone in Pseudomonas Sp. ZEA-1

    OpenAIRE

    2007-01-01

    The Pseudomonas sp. Strain ZEA-1 was isolated from rhizosphere of corn plant by an enrichment technique showed capability of utilizing zearalenone as the sole source of carbon. The bacterium rapidly utilized zearalenone beyond 200 µg/ml and showed prolific growth in a minimal medium containing 100 µg/ml zearalenone source. The course of ZEA degradation as well as the formation of its metabolites was observed by UV Spectrophotometer and thin layer chromatography analysis. Toxicity of biotransf...

  6. Battle in the New World: Helicoverpa armigera versus Helicoverpa zea (Lepidoptera: Noctuidae)

    Science.gov (United States)

    2016-01-01

    The corn earworm Helicoverpa zea (Boddie) and the old world bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) are allopatric species and occur in important agricultural crops. In maize, both species tend to infest the ear. The introduction of H. armigera in Brazil has created a new scenario, where these Helicoverpa species might cohabit and interact with one another, affecting the prevalence of each species in the agroecosystem, integrated pest management, and insect resistance management. In this study, larval occurrence and proportion of these species in maize was assessed in three regions of Brazil during three crop seasons. Interaction between the species was evaluated in interspecific and intraspecific scenarios under laboratory and field conditions. Helicoverpa zea was predominant in Rio Grande do Sul and the Planaltina, DF (central Brazil). In western Bahia, H. zea was predominant in the first collection, but approximately equal in number to H armigera in the second crop season. Both species exhibit high cannibalism/predation rates, and larval size was the primary factor for larval survival in the interaction studies. Larva of H. zea had higher survival when interacting with H. armigera, indicating that H. zea has an advantage in intraguild interactions with H. armigera in maize. Overall, the results from this study indicate that maize might play a role as a source of infestation or a sink of insecticide or Bt protein unselected H. armigera populations, depending on the H. zea:H. armigera intraguild competition and adult movement in the landscape. PMID:27907051

  7. The earliest archaeological maize (Zea mays L.) from highland Mexico: New accelerator mass spectrometry dates and their implications

    OpenAIRE

    Piperno, D.R.; Flannery, K. V.

    2001-01-01

    Accelerator mass spectrometry age determinations of maize cobs (Zea mays L.) from Guilá Naquitz Cave in Oaxaca, Mexico, produced dates of 5,400 carbon-14 years before the present (about 6,250 calendar years ago), making those cobs the oldest in the Americas. Macrofossils and phytoliths characteristic of wild and domesticated Zea fruits are absent from older strata from the site, although Zea pollen has previously been identified from those levels. These results, to...

  8. Extração de corantes de milho (Zea mays L. Extraction of corn colorants (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Felix Martin Cabajal Gamarra

    2009-03-01

    Full Text Available Os corantes naturais foram amplamente utilizados de forma artesanal até antes do surgimento dos corantes sintéticos. O estudo e uso dos corantes naturais voltaram a ter importância nestes últimos anos devido aos questionamentos dos organismos internacionais da saúde e dos consumidores pelo uso indiscriminado dos corantes sintéticos, ligados ao desenvolvimento de doenças degenerativas e ao impacto ambiental. O corante extraído do milho roxo (Zea mays L. tem sido utilizado ao longo da história pela civilização Inca na preparação de alimentos e no tingimento de fibras têxteis. Neste trabalho, os pigmentos do grupo das antocianinas foram extraídos das variedades de milho roxo e do milho vermelho (Z. mays L. e depois foram caracterizados. Três métodos de extração foram utilizados: imersão, lixiviação com algumas modificações e extração supercrítica (ESC. O melhor método para extração foi o da lixiviação que alcançou 88% (m/m de rendimento, em função da massa do corante extraído e da matéria-prima. Também utilizando a lixiviação modificada, foi possível concentrar em 3% os compostos acilados, assim como recuperar 85% dos solventes utilizados. Um indicador de pH foi obtido pela fixação das antocianinas num papel de filtro, com base na estabilidade das antocianinas, ferramenta que pode ser utilizada em laboratórios de ensino de química.Natural colorants were craftly made and widely used before the discovery of the synthetic colorants. The study and the use of natural colorants have become important again in the last few years due to questions raised by the international health organizations and consumers related to the indiscriminate use of synthetic colorants which were linked to the development of degenerative illnesses and environmental impact. The colorant extracted from purple corn (Zea Mays L. was used by the Inca civilization to prepare food and to dye textile fibers. In this work, pigments from the

  9. Nascent transcription affected by RNA polymerase IV in Zea mays.

    Science.gov (United States)

    Erhard, Karl F; Talbot, Joy-El R B; Deans, Natalie C; McClish, Allison E; Hollick, Jay B

    2015-04-01

    All eukaryotes use three DNA-dependent RNA polymerases (RNAPs) to create cellular RNAs from DNA templates. Plants have additional RNAPs related to Pol II, but their evolutionary role(s) remain largely unknown. Zea mays (maize) RNA polymerase D1 (RPD1), the largest subunit of RNA polymerase IV (Pol IV), is required for normal plant development, paramutation, transcriptional repression of certain transposable elements (TEs), and transcriptional regulation of specific alleles. Here, we define the nascent transcriptomes of rpd1 mutant and wild-type (WT) seedlings using global run-on sequencing (GRO-seq) to identify the broader targets of RPD1-based regulation. Comparisons of WT and rpd1 mutant GRO-seq profiles indicate that Pol IV globally affects transcription at both transcriptional start sites and immediately downstream of polyadenylation addition sites. We found no evidence of divergent transcription from gene promoters as seen in mammalian GRO-seq profiles. Statistical comparisons identify genes and TEs whose transcription is affected by RPD1. Most examples of significant increases in genic antisense transcription appear to be initiated by 3'-proximal long terminal repeat retrotransposons. These results indicate that maize Pol IV specifies Pol II-based transcriptional regulation for specific regions of the maize genome including genes having developmental significance.

  10. Ontogeny of the sheathing leaf base in maize (Zea mays).

    Science.gov (United States)

    Johnston, Robyn; Leiboff, Samuel; Scanlon, Michael J

    2015-01-01

    Leaves develop from the shoot apical meristem (SAM) via recruitment of leaf founder cells. Unlike eudicots, most monocot leaves display parallel venation and sheathing bases wherein the margins overlap the stem. Here we utilized computed tomography (CT) imaging, localization of PIN-FORMED1 (PIN1) auxin transport proteins, and in situ hybridization of leaf developmental transcripts to analyze the ontogeny of monocot leaf morphology in maize (Zea mays). CT imaging of whole-mounted shoot apices illustrates the plastochron-specific stages during initiation of the basal sheath margins from the tubular disc of insertion (DOI). PIN1 localizations identify basipetal auxin transport in the SAM L1 layer at the site of leaf initiation, a process that continues reiteratively during later recruitment of lateral leaf domains. Refinement of these auxin transport domains results in multiple, parallel provascular strands within the initiating primordium. By contrast, auxin is transported from the L2 toward the L1 at the developing margins of the leaf sheath. Transcripts involved in organ boundary formation and dorsiventral patterning accumulate within the DOI, preceding the outgrowth of the overlapping margins of the sheathing leaf base. We suggest a model wherein sheathing bases and parallel veins are both patterned via the extended recruitment of lateral maize leaf domains from the SAM.

  11. Arsenic accumulation in maize crop (Zea mays): a review.

    Science.gov (United States)

    Rosas-Castor, J M; Guzmán-Mar, J L; Hernández-Ramírez, A; Garza-González, M T; Hinojosa-Reyes, L

    2014-08-01

    Arsenic (As) is a metalloid that may represent a serious environmental threat, due to its wide abundance and the high toxicity particularly of its inorganic forms. The use of arsenic-contaminated groundwater for irrigation purposes in crop fields elevates the arsenic concentration in topsoil and its phytoavailability for crops. The transfer of arsenic through the crops-soil-water system is one of the more important pathways of human exposure. According to the Food and Agriculture Organization of the United Nations, maize (Zea mays L.) is the most cultivated cereal in the world. This cereal constitutes a staple food for humans in the most of the developing countries in Latin America, Africa, and Asia. Thus, this review summarizes the existing literature concerning the conditions involved in agricultural soil that leads to As influx into maize crops and the uptake mechanisms, metabolism and phytotoxicity of As in corn plants. Additionally, the studies of the As accumulation in raw corn grain and corn food are summarized, and the As biotransfer into the human diet is highlighted. Due to high As levels found in editable plant part for livestock and humans, the As uptake by corn crop through water-soil-maize system may represent an important pathway of As exposure in countries with high maize consumption.

  12. RNA-seq Analysis of Cold and Drought Responsive Transcriptomes of Zea mays ssp. mexicana L.

    Science.gov (United States)

    Lu, Xiang; Zhou, Xuan; Cao, Yu; Zhou, Meixue; McNeil, David; Liang, Shan; Yang, Chengwei

    2017-01-01

    The annual Zea mays ssp. mexicana L. is a member of teosinte, a wild relative of the Zea mays spp. mays L. This subspecies has strong growth and regeneration ability, high tiller numbers, high protein and lysine content as well as resistance to many fungal diseases, and it can be effectively used in maize improvement. In this study, we reported a Zea mays ssp. mexicana L. transcriptome by merging data from untreated control (CK), cold (4°C) and drought (PEG2000, 20%) treated plant samples. A total of 251,145 transcripts (N50 = 1,269 bp) and 184,280 unigenes (N50 = 923 bp) were predicted, which code for homologs of near 47% of the published maize proteome. Under cold conditions, 2,232 and 817 genes were up-regulated and down-regulated, respectively, while fewer genes were up-regulated (532) and down-regulated (82) under drought stress, indicating that Zea mays ssp. mexicana L. is more sensitive to the applied cold rather than to the applied drought stresses. Functional enrichment analyses identified many common or specific biological processes and gene sets in response to drought and cold stresses. The ABA dependent pathway, trehalose synthetic pathway and the ICE1-CBF pathway were up-regulated by both stresses. GA associated genes have been shown to differentially regulate the responses to cold in close subspecies in Zea mays. These findings and the identified functional genes can provide useful clues for improving abiotic stress tolerance of maize.

  13. Biology, Ecology, and Evolving Management of Helicoverpa zea (Lepidoptera: Noctuidae) in Sweet Corn in the United States.

    Science.gov (United States)

    Olmstead, Daniel L; Nault, Brian A; Shelton, Anthony M

    2016-08-01

    The corn earworm, Helicoverpa zea (Boddie), is a polyphagous pest found throughout the United States, where it attacks many field and vegetable crops. Although H. zea has long been a traditional pest of sweet corn, its importance to this crop has increased dramatically over the past two decades. In this review, we summarize information critical for current and future management of H. zea in sweet corn production in the United States. First, we discuss the pest status of H. zea and its life history, including migration, infestation and larval development, diapause, overwintering, and abiotic factors that affect its biology. Next we describe monitoring methods, crop protection decision-making processes, chemical control options, and the use of genetic technologies for control of H. zea Alternative H. zea management options including biological control, cultural controls, host plant resistance, and pheromone disruption are also reviewed. The role of climate change and its effects on H. zea and its ecology are discussed, as well as the recent invasion of its relative, Helicoverpa armigera (Hübner), which is a major pest of corn in other parts of the world. To conclude, we suggest future research opportunities for H. zea and H. armigera management in sweet corn.

  14. The earliest archaeological maize (Zea mays L.) from highland Mexico: new accelerator mass spectrometry dates and their implications.

    Science.gov (United States)

    Piperno, D R; Flannery, K V

    2001-02-13

    Accelerator mass spectrometry age determinations of maize cobs (Zea mays L.) from Guilá Naquitz Cave in Oaxaca, Mexico, produced dates of 5,400 carbon-14 years before the present (about 6,250 calendar years ago), making those cobs the oldest in the Americas. Macrofossils and phytoliths characteristic of wild and domesticated Zea fruits are absent from older strata from the site, although Zea pollen has previously been identified from those levels. These results, together with the modern geographical distribution of wild Zea mays, suggest that the cultural practices that led to Zea domestication probably occurred elsewhere in Mexico. Guilá Naquitz Cave has now yielded the earliest macrofossil evidence for the domestication of two major American crop plants, squash (Cucurbita pepo) and maize.

  15. Graviresponsiveness of surgically altered primary roots of Zea mays

    Science.gov (United States)

    Maimon, E.; Moore, R.

    1991-01-01

    We examined the gravitropic responses of surgically altered primary roots of Zea mays to determine the route by which gravitropic inhibitors move from the root tip to the elongating zone. Horizontally oriented roots, from which a 1-mm-wide girdle of epidermis plus 2-10 layers of cortex were removed from the apex of the elongating zone, curve downward. However, curvature occurred only apical to the girdle. Filling the girdle with mucilage-like material transmits curvature beyond the girdle. Vertically oriented roots with a half-girdle' (i.e. the epidermis and 2-10 layers of the cortex removed from half of the circumference of the apex of the elongating zone) curve away from the girdle. Inserting the half-girdle at the base of the elongating zone induces curvature towards the girdle. Filling the half-circumference girdles with mucilage-like material reduced curvature significantly. Stripping the epidermis and outer 2-5 layers of cortex from the terminal 1.5 cm of one side of a primary root induces curvature towards the cut, irrespective of the root's orientation to gravity. This effect is not due to desiccation since treated roots submerged in water also curved towards their cut surface. Coating a root's cut surface with a mucilage-like substance minimizes curvature. These results suggest that the outer cell-layers of the root, especially the epidermis, play an important role in root gravicurvature, and the gravitropic signals emanating from the root tip can move apoplastically through mucilage.

  16. Use of Zea mays L. in phytoremediation of trichloroethylene.

    Science.gov (United States)

    Moccia, Emanuele; Intiso, Adriano; Cicatelli, Angela; Proto, Antonio; Guarino, Francesco; Iannece, Patrizia; Castiglione, Stefano; Rossi, Federico

    2016-09-13

    Trichloroethylene (TCE) is a chlorinated aliphatic organic compound often detected as pollutant in soils and ground water. "Green technologies" based on phytoremediation were proven to be effective to reclaim organic pollutants (e.g. TCE) and heavy metals from different environmental matrices. In this work, we use Zea mays L. for the removal of high TCE concentrations from medium cultures. In particular, we investigated a sealed bioreactor where the growth medium was contaminated with an increasing amount of TCE, in the range 55-280 mg/L; the removal capability of the maize plants was assessed by means of GC-MS and LC-MS analyses. An accurate mass balance of the system revealed that the plants were able to remove and metabolise TCE with an efficiency up to 20 %, depending on the total amount of TCE delivered in the bioreactor. Morphometric data showed that the growth of Z. mays is not significantly affected by the presence of the pollutant up to a concentration of 280 mg/L, while plants show significant alterations at higher TCE concentrations until the growth is completely inhibited for [TCE] ≃ 2000 mg/L. Finally, the presence of several TCE metabolites, including dichloroacetic and trichloroacetic acids, was detected in the roots and in the aerial part of the plants, revealing that Z. mays follows the green liver metabolic model. These results encourage further studies for the employment of this plant species in phytoremediation processes of soils and waters contaminated by TCE and, potentially, by many other chlorinated solvents.

  17. Occurrence and metabolism of 7-hydroxy-2-indolinone-3-acetic acid in Zea mays

    Science.gov (United States)

    Lewer, P.; Bandurski, R. S.

    1987-01-01

    7-Hydroxy-2-indolinone-3-acetic acid was identified as a catabolite of indole-3-acetic acid in germinating kernels of Zea mays and found to be present in amounts of ca 3.1 nmol/kernel. 7-Hydroxy-2-indolinone-3-acetic acid was shown to be a biosynthetic intermediate between 2-indolinone-3-acetic acid and 7-hydroxy-2-indolinone-3-acetic acid-7'-O-glucoside in both kernels and roots of Zea mays. Further metabolism of 7-hydroxy-2-[5-3H]-indolinone-3-acetic acid-7'-O-glucoside occurred to yield tritiated water plus, as yet, uncharacterized products.

  18. The effect of lead on the photoelectric reaction of Zea mays L. plants.

    Science.gov (United States)

    Pazurkiewicz-Kocot, K; Pietruszka, M

    2000-09-01

    We investigate the correlation between the concentrations of lead (10(-6)-10(-2) mol dm(-3) PbCl2) in the external medium and photoelectric reaction of Zea mays L. plants. The experiments were carried out on 8-10-day-old maize plants (Zea mays L. var. K33 x F2) with the use of conventional electrophysiological technique. The results suggest that in plants treated with lead ions the photoelectric reaction is significantly reduced. The pH variation of the incubation medium including the green fragments of leaves showed that lead ions caused inhibition of light-induced external acidification.

  19. Impuesto sobre la renta

    OpenAIRE

    Universitat de Barcelona. Grup d'Innovació Docent en Economia dels Impostos (GIDEI)

    2016-01-01

    Tema 7. Esquema de presentación del tema "Impuesto sobre la renta". Incorpora datos actuales, gráficos, cuadros y tablas. Esquema de presentació del tema "Impuesto sobre la renta". Incorpora dades actuals, gràfics, quadres i taules.

  20. Impuesto sobre sociedades

    OpenAIRE

    Universitat de Barcelona. Grup d'Innovació Docent en Economia dels Impostos

    2016-01-01

    Tema 8. Esquemas de la presentación del tema "Impuesto sobre sociedades". Incorpora datos actuales, gráficos, cuadros y tablas. Esquemes de la presentació del tema "Impuesto sobre sociedades". Incorpora dades actuals, gràfics, quadres i taules

  1. Digital signage sobre IP

    OpenAIRE

    Casademont Filella, Albert

    2012-01-01

    Projecte que versa sobre el disseny i la implementació d'un sistema de Digital Signage (Cartelleria Digital) sobre IP, creant un gestor que permeti controlar de forma remota tot un conjunt de petits dispositius connectats a pantalles que emeten continguts multimèdia com vídeos, imatges, feeds rss...

  2. Production and characterization of amylases from Zea mays malt

    Directory of Open Access Journals (Sweden)

    Joana Paula Menezes Biazus

    2009-08-01

    Full Text Available In this work the α and β-amylase enzymes were obtained from maize (Zea mays malt and were biochemistry characterized. A germination study to obtain the maize malt with good amylase activity was made. The maize seeds were germinated in laboratory and the enzymatic activity was measured daily. Activity dependence to germination time were fitted to an exponential model (A=A0eµt, which showed that the behaviour of enzymatic activity in the germination process was similar to the growth of the microorganism. Its model could be applied to describe the mechanism of α-amylase production for each maize varieties and others cereals. Maize malt characterization showed that α and β-amylase had optimal pH between 4-6.5, optimal temperature 50 and 90ºC, and molecular weight of 67.4 and 47.5kDa, respectively. This work contributed with the advances in biotechnology generating of conditions for application of a new and of low price amylases source.Neste trabalho as enzimas α e β-amilases foram obtidas de malte de milho e depois foram caracterizadas bioquimicamente. Um estudo da germinação foi feito para obtenção do malte com boa atividade amilásica. A germinação ocorreu em escala laboratorial e a atividade enzimática foi medida diariamente. Um modelo exponencial do tipo A=A0eµt foi ajustado a dependência do tempo de germinação com a atividade, mostrando que o comportamento da atividade enzimática no processo de germinação é semelhante ao crescimento de microorganismos. Este modelo pode ser aplicado para descrever o mecanismo de produção da α-amilase para cada variedade de milho e de outros cereais. A caracterização do malte de milho mostrou que as α e β-amilase têm pH ótimo entre 4,0-6,5, temperatura ótima de 50 e 90ºC, e massa molar de 67,4 e 47,5 kDa, respectivamente. Este trabalho contribuiu com os avanços da biotecnologia gerando condições de emprego de uma nova e barata fonte de amilases.

  3. INVENTARISASI GULMA PADA TANAMAN JAGUNG (Zea mays L. DI LAHAN SAWAH KELURAHAN PADANG GALAK, DENPASAR TIMUR, KODYA DENPASAR, PROVINSI BALI

    Directory of Open Access Journals (Sweden)

    SURYANINGSIH -

    2013-05-01

    Full Text Available This study aims to determine the weed species that exist on Zea mays L. plant in paddyfields Padang Galak village, East Denpasar, Bali Province. This study is useful to provideinformation about the species of weeds found in maize (Zea mays L. in the fields of biology andagriculture, so weed control on Zea mays L. Plant can be implemented.Research was conducted from January 7 until March 11, 2011. In this study used themethod of cruising (exsploration sampling. To be more efficient and systematic results, alsoused a systematic method of lines.The results found 36 weed species belonging to 20 families. The distribution of theweed species, was found in Zea mays L. plant age of 4 weeks, which composed of 8 families 16Species. Weeds found in Zea mays L. plants aged of 6 weeks (the formation of fruit consistedof 10 familes and 23 species. While weeds found in Zea mays L. plants 8 weeks of age(ripening fruit were 14 families and 28 species. Weeds found in Zea mays L. plants aged 10weeks (before harvest comprised of 20 families and 36 species.

  4. Potassium fertilization mitigates the adverse effects of drought on selected Zea mays cultivars

    Science.gov (United States)

    In the present study, the role of potassium (K) in mitigating the adverse effects of drought stress (DS) on 2 maize (Zea mays L.) cultivars, ‘Shaandan 9’ (S9; drought-tolerant) and ‘Shaandan 911’ (S911; drought-sensitive), was assessed. K application increased dry matter (DM) across all growth stage...

  5. Identification and characterization of digestive serine proteases from inhibitor-resistant Helicoverpa zea larval midgut

    NARCIS (Netherlands)

    Volpicella, M.; Cordewener, J.H.G.; Jongsma, M.A.; Gallerani, R.; Ceci, L.R.; Beekwilder, M.J.

    2006-01-01

    Protease inhibitors mediate a natural form of plant defence against insects, by interfering with the digestive system of the insect. In this paper, affinity chromatography was used to isolate trypsins and chymotrypsins from Helicoverpa zea larvae, which had been raised on inhibitor-containing diet.

  6. Purification and characterization of recombinant protein kinase CK2 from Zea mays expressed in Escherichia coli

    DEFF Research Database (Denmark)

    Riera, Marta; Pages, Montserrat; Issinger, Olaf Georg;

    2003-01-01

    Recombinant protein kinase subunits rmCK2alpha-1 and rmCK2beta-1 from Zea mays were expressed separately in Escherichia coli and assembled to a fully active tetrameric holoenzyme complex in vitro. The obtained maize holoenzyme was purified to homogeneity, biochemically characterized, and compared...

  7. Cloning and sequencing of the casein kinase 2 alpha subunit from Zea mays

    DEFF Research Database (Denmark)

    Dobrowolska, G; Boldyreff, B; Issinger, O G

    1991-01-01

    The nucleotide sequence of the cDNA coding for the alpha subunit of casein kinase 2 of Zea mays has been determined. The cDNA clone contains an open reading frame of 996 nucleotides encoding a polypeptide comprising 332 amino acids. The primary amino acid sequence exhibits 75% identity to the alpha...

  8. Characterization of phenylpropanoid pathway genes within European maize (Zea mays L.) inbreds

    DEFF Research Database (Denmark)

    Andersen, Jeppe Reitan; Zein, Imad; Wenzel, Gerhard;

    2008-01-01

    genomic fragments of six putative phenylpropanoid pathway genes in a panel of elite European inbred lines of maize (Zea mays L.) contrasting in forage quality traits. Six loci, encoding C4H, 4CL1, 4CL2, C3H, F5H, and CAD, displayed different levels of nucleotide diversity and linkage disequilibrium (LD...

  9. Chromosomal Location by Use of Trisomics and New Alleles of an Endopeptidase in Zea Mays

    DEFF Research Database (Denmark)

    Nielsen, Gunnar Gissel; Scandalios, John G.

    1974-01-01

    An association was found earlier between the Ep1 gene locus coding for an endopeptidase and the endosperm color gene Y1 on chromosome 6 of Zea mays. By employing primary trisomics we have unequivocally placed the Ep1 gene on chromosome 6, closely linked to the Y1 locus. Additionally we describe new...

  10. Isolation of EF1gamma from calli regenerating SSH library in Maize (Zea mays).

    Science.gov (United States)

    Xia, Y L; Ding, J; Zhang, Z M; Rong, T Z; Shi, L Y; Pan, G T

    2007-12-01

    18599Hong, a good Maize (Zea mays) inbred line as well as good transformation acceptor with high regeneration capacity, was used for isolating embryonic callus regeneration genes. Subtractive library was constructed by Suppression subtractive hybridization and screened by Reverse Northern Hybridization. The clones of No. 27 was randomly picked to sequence. NCBI blastx results showed the similarity to elongation factor 1gamma in rice.

  11. Differential distribution of cadmium in lettuce (Lactuca sativa L.) and maize (Zea mays L.).

    NARCIS (Netherlands)

    Florijn, P.J.

    1993-01-01

    Large genotypic variation in shoot Cd concentrations has been reported in literature for several plant species including lettuce ( Lactuca sativa L.) and maize ( Zea mays L.). The objective of this thesis was to elucidate the physiological andlor morphological basis of this differential behaviour us

  12. Identification and characterization of a Zea mays line carrying a transposon-tagged ENOD40

    NARCIS (Netherlands)

    Compaan, B.; Ruttink, T.; Albrecht, C.; Meeley, R.; Bisseling, T.; Franssen, H.G.J.M.

    2003-01-01

    In Zea mays, two ENOD40 homologous were identified that show only 30% of sequence homology to each other. We identified line e40-mum1 carrying a Mu transposon inserted in ZmENOD40-1, the maize gene that has the highest homology to leguminous ENOD40. The insertion causes a dramatic reduction of the Z

  13. Molecular cloning and functional characterization of the diapause hormone receptor in the corn earworm Helicoverpa zea

    Science.gov (United States)

    The diapause hormone (DH) in the heliothine moth has shown its activity in termination of pupal diapause, while the orthology in the silkworm is known to induce embryonic diapause. In the current study, we cloned the diapause hormone receptor from the corn earworm Helicoverpa zea (HzDHr) and tested ...

  14. Cytodifferentiation during callus initiation and somatic embryogenesis in Zea mays L.

    NARCIS (Netherlands)

    Fransz, P.F.

    1988-01-01

    This thesis deals with cytomorphogenic aspects during various phases of regeneration in tissue cultures of Zeamays L. Regeneration through tissue culture has been shown in an increasing number of plant species and is applied on large scale in agriculture and horticulture. Nevertheless,

  15. Effects of cotton condensed tannin, maysin (Corn) and pinitol (soybeans) onHeliothis zea growth and development.

    Science.gov (United States)

    Reese, J C; Chan, B G; Waiss, A C

    1982-12-01

    Maysin, a flavone glycoside from corn silks, inhibits ingestion, and thus growth, ofHeliothis zea (Boddie) larvae. Pinitol from soybeans inhibitedH. zea growth by the same mechanism. Despite the widely held assumption that tannins inhibit growth by inhibiting assimilation, cotton condensed tannin inhibitedH. zea growth by reducing ingestion; no evidence was found for a reduction in assimilation. Neonate larvae are shown to be much more sensitive to allelochemics than larvae that have fed on control diet before being transferred to diet containing plant allelochemics.

  16. ZEA-TDMA: design and system level implementation of a TDMA protocol for anonymous wireless networks

    Science.gov (United States)

    Banerjee, Debasmit; Dong, Bo; Biswas, Subir

    2013-05-01

    Wireless sensor network used in military applications may be deployed in hostile environments, where privacy and security is of primary concern. This can lead to the formation of a trust-based sub-network among mutually-trusting nodes. However, designing a TDMA MAC protocol is very challenging in situations where such multiple sub-networks coexist, since TDMA protocols require node identity information for slot assignments. This paper introduces a novel distributed TDMA MAC protocol, ZEA-TDMA (Zero Exposure Anonymous TDMA), for anonymous wireless networks. ZEA-TDMA achieves slot allocation with strict anonymity constraints, i.e. without nodes having to exchange any identity revealing information. By using just the relative time of arrival of packets and a novel technique of wireless collision-detection and resolution for fixed packetsizes, ZEA-TDMA is able to achieve MAC slot-allocation which is described as follows. Initially, a newly joined node listens to its one-hop neighborhood channel usage and creates a slot allocation table based on its own relative time, and finally, selects a slot that is collision free within its one-hop neighborhood. The selected slot can however cause hidden collisions with a two-hop neighbor of the node. These collisions are resolved by a common neighbor of the colliding nodes, which first detects the collision, and then resolve them using an interrupt packet. ZEA-TDMA provides the following features: a) it is a TDMA protocol ideally suited for highly secure or strictly anonymous environments b) it can be used in heterogeneous environments where devices use different packet structures c) it does not require network time-synchronization, and d) it is insensitive to channel errors. We have implemented ZEA-TDMA on the MICA2 hardware platform running TinyOS and evaluated the protocol functionality and performance on a MICA2 test-bed.

  17. Production and characterization of Bacillus thuringiensis Cry1Ac-resistant cotton bollworm Helicoverpa zea (Boddie).

    Science.gov (United States)

    Anilkumar, Konasale J; Rodrigo-Simón, Ana; Ferré, Juan; Pusztai-Carey, Marianne; Sivasupramaniam, Sakuntala; Moar, William J

    2008-01-01

    Laboratory-selected Bacillus thuringiensis-resistant colonies are important tools for elucidating B. thuringiensis resistance mechanisms. However, cotton bollworm, Helicoverpa zea, a target pest of transgenic corn and cotton expressing B. thuringiensis Cry1Ac (Bt corn and cotton), has proven difficult to select for stable resistance. Two populations of H. zea (AR and MR), resistant to the B. thuringiensis protein found in all commercial Bt cotton varieties (Cry1Ac), were established by selection with Cry1Ac activated toxin (AR) or MVP II (MR). Cry1Ac toxin reflects the form ingested by H. zea when feeding on Bt cotton, whereas MVP II is a Cry1Ac formulation used for resistance selection and monitoring. The resistance ratio (RR) for AR exceeded 100-fold after 11 generations and has been maintained at this level for nine generations. This is the first report of stable Cry1Ac resistance in H. zea. MR crashed after 11 generations, reaching only an RR of 12. AR was only partially cross-resistant to MVP II, suggesting that MVP II does not have the same Cry1Ac selection pressure as Cry1Ac toxin against H. zea and that proteases may be involved with resistance. AR was highly cross-resistant to Cry1Ab toxin but only slightly cross-resistant to Cry1Ab expressing corn leaf powder. AR was not cross-resistant to Cry2Aa2, Cry2Ab2-expressing corn leaf powder, Vip3A, and cypermethrin. Toxin-binding assays showed no significant differences, indicating that resistance was not linked to a reduction in binding. These results aid in understanding why this pest has not evolved B. thuringiensis resistance, and highlight the need to choose carefully the form of B. thuringiensis protein used in experiments.

  18. Influence of microgravity on cellular differentiation in root caps of Zea mays

    Science.gov (United States)

    Moore, R.; Fondren, W. M.; McClelen, C. E.; Wang, C. L.

    1987-01-01

    We launched imbibed seeds of Zea mays into outer space aboard the space shuttle Columbia to determine the influence of microgravity on cellular differentiation in root caps. The influence of microgravity varied with different stages of cellular differentiation. Overall, microgravity tended to 1) increase relative volumes of hyaloplasm and lipid bodies, 2) decrease the relative volumes of plastids, mitochondria, dictyosomes, and the vacuome, and 3) exert no influence on the relative volume of nuclei in cells comprising the root cap. The reduced allocation of dictyosomal volume in peripheral cells of flight-grown seedlings correlated positively with their secretion of significantly less mucilage than peripheral cells of Earth-grown seedlings. These results indicate that 1) microgravity alters the patterns of cellular differentiation and structures of all cell types comprising the root cap, and 2) the influence of microgravity on cellular differentiation in root caps of Zea mays is organelle specific.

  19. Influence of calcium phosphate nanoparticles, Piriformospora indica and Glomus mosseae on growth of Zea mays

    Science.gov (United States)

    Rane, Mansi; Bawskar, Manisha; Rathod, Dnyaneshwar; Nagaonkar, Dipali; Rai, Mahendra

    2015-12-01

    In this study, the arbuscular mycorrhizal fungus (G. mosseae) and endosymbiont (P. indica) colonized Zea mays were treated with calcium phosphate nanoparticles (CaPNPs) and evaluated for their plant growth promotion efficiency. It was observed that CaPNPs in combination with both G. mosseae and P. indica are more potent plant growth promoter than independent combinations of CaPNPs + G. mosseae, CaPNPs + P. indica or CaPNPs alone. The fluorimetric studies of treated plants revealed that CaPNPs alone and in combination with P. indica can enhance vitality of Zea mays by improving chlorophyll a content and performance index of treated plants. Hence, we conclude that CaPNPs exhibit synergistic growth promotion, root proliferation and vitality improvement properties along with endosymbiotic and arbuscular mycorrhizal fungi, which after further field trials can be developed as a cost-effective nanofertilizer with pronounced efficiency.

  20. Inducing gravitropic curvature of primary roots of Zea mays cv Ageotropic

    Science.gov (United States)

    Moore, R.; Evans, M. L.; Fondren, W. M.

    1990-01-01

    Primary roots of the mutant 'Ageotropic' cultivar of Zea mays are nonresponsive to gravity. Their root caps secrete little or no mucilage and touch the root only at the extreme apex. A gap separates the cap and root at the periphery of the cap. Applying mucilage from normal roots or substances with a consistency similar to that of mucilage to tips of mutant roots causes these roots to become strongly graviresponsive. Gravicurvature stops when these substances are removed. Caps of some mutants secrete small amounts of mucilage and are graviresponsive. These results indicate that (a) the lack of graviresponsiveness in the mutant results from disrupting the transport pathway between the cap and root, (b) movement of the growth-modifying signal from the cap to the root occurs via an apoplastic pathway, and (c) mucilage is necessary for normal communication between the root cap and root in Zea mays cv Ageotropic.

  1. Optimization of drying process of Zea Mays malt to use as alternative source of amylolytics enzymes

    Directory of Open Access Journals (Sweden)

    Joana Paula Menezes Biazus

    2005-06-01

    Full Text Available This work aimed to study the drying process optimization of maize (Zea Mays malt for obtaining maize malt, without affecting enzymatic activity of alpha e beta-amylases from maize malt. Results showed that dryer operation must occur in zone at 54°C and 5.18-6 h process time. The maize malt obtained had good enzymatic properties.Este trabalho objetivou a otimização da secagem do malte de milho (Zea Mays para obter um malte sem afetar a atividade das enzimas presentes neste, alfa e beta -amilases. Os resultados mostraram que a operação do secador deve ser feita a 54°C e entre 5,18-6 h de processo. O malte obtido possuiu boas propriedades enzimáticas.

  2. Abscisic acid is not necessary for gravitropism in primary roots of Zea mays

    Science.gov (United States)

    Moore, R.

    1990-01-01

    Primary roots of Zea mays L. cv. Tx 5855 treated with fluridone are strongly graviresponsive, but have undetectable levels of abscisic acid (ABA). Primary roots of the carotenoid-deficient w-3, vp-5, and vp-7 mutants of Z. mays are also graviresponsive despite having undetectable amounts of ABA. Graviresponsive roots of untreated and wild-type seedlings contain 286 to 317 ng ABA g-1 f. wt, respectively. These results indicate that ABA is not necessary for root gravicurvature.

  3. Movement of endogenous calcium in the elongating zone of graviresponding roots of Zea mays

    Science.gov (United States)

    Moore, R.; Cameron, I. L.; Smith, N. K.

    1989-01-01

    Endogenous calcium (Ca) accumulates along the lower side of the elongating zone of horizontally oriented roots of Zea mays cv. Yellow Dent. This accumulation of Ca correlates positively with the onset of gravicurvature, and occurs in the cytoplasm, cell walls and mucilage of epidermal cells. Corresponding changes in endogenous Ca do not occur in cortical cells of the elongating zone of intact roots. These results indicate that the calcium asymmetries associated with root gravicurvature occur in the outermost layers of the root.

  4. PENYELENGGARAAN MAKANAN DAN TINGKAT KEPUASAN KONSUMEN DI KANTIN ZEA MAYS INSTITUT PERTANIAN BOGOR

    Directory of Open Access Journals (Sweden)

    Arnati Wulansari

    2013-11-01

    Full Text Available ABSTRACTThis research aimed was to know food service and level of customer satisfaction in the Zea Mays cafetaria at Bogor Agricultural University. Case study and descriptive analysis were applied in this study. Sampling method of purposive sampling was carried out and number of subjects used was 95 people. The food service in the Zea Mays cafetaria consists of planning, purchasing, receiving, storing, processing, and distributing. The result of analysis based on Importance Performance Analysis showed that the most important attribute was the security and hygiene product and the highest performance levels was the cleanliness of dining room. More than fifty percent subjects was concerned against nutrient content of the menu (50.5%. Based on the Customer Satisfaction Index the satisfaction value was 69.3 (satisfied. There was a correlation between job and education level with quality of the product and between income with nutrient content (p<0.05.Keywords: customer, food service, satisfactionABSTRAKPenelitian ini bertujuan untuk mengetahui penyelenggaraan makanan dan tingkat kepuasan konsumen di Kantin Zea Mays Institut Pertanian Bogor. Penelitian ini menggunakan metode penelitian analisis deskriptif dan studi kasus. Metode penarikan subjek dilakukan secara purposive dan sebanyak 95 subjek digunakan dalam penelitian ini. Penyelenggaraan makanan di Kantin Zea Mays terdiri dari perencanaan, pembelian, penerimaan, penyimpanan, pengolahan, dan penyajian. Berdasarkan hasil analisis Importance Performance Analysis (IPA diketahui bahwa atribut yang dirasakan paling penting adalah keamanan dan kebersihan produk sedangkan atribut tingkat kinerja yang paling tinggi skornya adalah kebersihan tempat makan. Lebih dari separuh subjek masih memerhatikan kandungan gizi menu (50.5%. Berdasarkan Customer Satisfaction Index (CSI diperoleh nilai kepuasan sebesar 69.3 (puas. Terdapat hubungan antara pekerjaan dan tingkat pendidikan dengan penilaian atribut mutu produk

  5. Conservation and diversity of seed associated endophytes in Zea across boundaries of evolution, ethnography and ecology.

    Science.gov (United States)

    Johnston-Monje, David; Raizada, Manish N

    2011-01-01

    Endophytes are non-pathogenic microbes living inside plants. We asked whether endophytic species were conserved in the agriculturally important plant genus Zea as it became domesticated from its wild ancestors (teosinte) to modern maize (corn) and moved from Mexico to Canada. Kernels from populations of four different teosintes and 10 different maize varieties were screened for endophytic bacteria by culturing, cloning and DNA fingerprinting using terminal restriction fragment length polymorphism (TRFLP) of 16S rDNA. Principle component analysis of TRFLP data showed that seed endophyte community composition varied in relation to plant host phylogeny. However, there was a core microbiota of endophytes that was conserved in Zea seeds across boundaries of evolution, ethnography and ecology. The majority of seed endophytes in the wild ancestor persist today in domesticated maize, though ancient selection against the hard fruitcase surrounding seeds may have altered the abundance of endophytes. Four TRFLP signals including two predicted to represent Clostridium and Paenibacillus species were conserved across all Zea genotypes, while culturing showed that Enterobacter, Methylobacteria, Pantoea and Pseudomonas species were widespread, with γ-proteobacteria being the prevalent class. Twenty-six different genera were cultured, and these were evaluated for their ability to stimulate plant growth, grow on nitrogen-free media, solubilize phosphate, sequester iron, secrete RNAse, antagonize pathogens, catabolize the precursor of ethylene, produce auxin and acetoin/butanediol. Of these traits, phosphate solubilization and production of acetoin/butanediol were the most commonly observed. An isolate from the giant Mexican landrace Mixteco, with 100% identity to Burkholderia phytofirmans, significantly promoted shoot potato biomass. GFP tagging and maize stem injection confirmed that several seed endophytes could spread systemically through the plant. One seed isolate

  6. Conservation and diversity of seed associated endophytes in Zea across boundaries of evolution, ethnography and ecology.

    Directory of Open Access Journals (Sweden)

    David Johnston-Monje

    Full Text Available Endophytes are non-pathogenic microbes living inside plants. We asked whether endophytic species were conserved in the agriculturally important plant genus Zea as it became domesticated from its wild ancestors (teosinte to modern maize (corn and moved from Mexico to Canada. Kernels from populations of four different teosintes and 10 different maize varieties were screened for endophytic bacteria by culturing, cloning and DNA fingerprinting using terminal restriction fragment length polymorphism (TRFLP of 16S rDNA. Principle component analysis of TRFLP data showed that seed endophyte community composition varied in relation to plant host phylogeny. However, there was a core microbiota of endophytes that was conserved in Zea seeds across boundaries of evolution, ethnography and ecology. The majority of seed endophytes in the wild ancestor persist today in domesticated maize, though ancient selection against the hard fruitcase surrounding seeds may have altered the abundance of endophytes. Four TRFLP signals including two predicted to represent Clostridium and Paenibacillus species were conserved across all Zea genotypes, while culturing showed that Enterobacter, Methylobacteria, Pantoea and Pseudomonas species were widespread, with γ-proteobacteria being the prevalent class. Twenty-six different genera were cultured, and these were evaluated for their ability to stimulate plant growth, grow on nitrogen-free media, solubilize phosphate, sequester iron, secrete RNAse, antagonize pathogens, catabolize the precursor of ethylene, produce auxin and acetoin/butanediol. Of these traits, phosphate solubilization and production of acetoin/butanediol were the most commonly observed. An isolate from the giant Mexican landrace Mixteco, with 100% identity to Burkholderia phytofirmans, significantly promoted shoot potato biomass. GFP tagging and maize stem injection confirmed that several seed endophytes could spread systemically through the plant. One seed

  7. Antihypertensive and antioxidant activity of atomized andean purple corn (Zea mayz L) hydroalcoholic extract in rats

    OpenAIRE

    Arroyo, Jorge; Facultad de Medicina, Universidad Nacional Mayor de San Marcos. Lima, Perú. Químico farmaceútico.; Raez, Ernesto; Facultad de Medicina, Universidad Nacional Mayor de San Marcos. Lima, Perú. Médico patólogo.; Rodríguez, Miguel; Facultad de Odontología, Universidad Nacional Mayor de San Marcos. Lima, Perú. Odontólogo.; Chumpitaz, Víctor; Facultad Odontología, Universidad Nacional Mayor de San Marcos. Lima, Perú. Odontólogo.; Burga, Jonny; Facultad de Odontología, Universidad Nacional Mayor de San Marcos. Lima, Perú. Odontólogo.; De la Cruz, Walter; Facultad de Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos. Lima, Perú. Médico.; Valencia, José; Facultad de Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos. Lima, Perú. Químico Farmacéutico.

    2008-01-01

    Objectives. To determine the antihypertensive and antioxidant activity of the atomized hydroalcoholic extract of Zea mays L. (Andean purple corn) in rats with induced hypertension. Material and methods. We used five groups of six Holtzmann rats each, one without hypertension (negative control) and four with hypertension induced by L-NAME: positive control and three groups for the doses of 250, 500 and 1000 mg/kg, respectively. The treatment was carried out orally once a day for 25 days. Th...

  8. La historia de las ideas en la perspectiva de Leopoldo Zea.

    Directory of Open Access Journals (Sweden)

    Susana Vázquez

    2015-09-01

    Full Text Available Leopoldo Zea (México 1912 para muchos el mayor pensador de Hispanoamérica en la segunda mitad del siglo XX, ejerce un indudable magisterio en elplano de la historia de las idas a nivel continental (...Contenido: Introducción. Contexto histórico y genealogía de sus conceptos fundamentales. Análisis de algunas de sus obras. Reflexión final

  9. Comparative toxicity of mycotoxins to navel orangeworm (Amyelois transitella) and corn earworm (Helicoverpa zea).

    Science.gov (United States)

    Niu, Guodong; Siegel, Joel; Schuler, Mary A; Berenbaum, May R

    2009-08-01

    Mycotoxins, such as aflatoxins and ochratoxins, are widely distributed in nature and are frequently problematic crop contaminants that cause millions of dollars of annual losses in the United States. Insect infestations of crop plants significantly exacerbate mycotoxin contamination. Damage to a variety of nut species by Amyelois transitella Walker (navel orangeworm, NOW) is associated with infection by Aspergillus species and concomitant production of aflatoxins and ochratoxins. Resistance to aflatoxins in this lepidopteran is compared here with the levels of resistance in Helicoverpa zea (corn earworm, CEW), another lepidopteran that routinely encounters aflatoxins in its diet, albeit at lower levels. Measured as the developmental delay caused by aflatoxin B1 (AFB1), it is apparent that the LC(50) (defined as the concentration preventing 50% of newly hatched larvae from entering the 2nd instar within 48 h) for AFB1 is 100 times greater for A. transitella than for H. zea. Similarly, A. transitella 1st instars display substantially higher tolerance to ochratoxin A, another mycotoxin contaminant produced by Aspergillus species, than do H. zea. Our studies indicate that A. transitella, although a hostplant generalist, may well be highly specialized for mycotoxin detoxification.

  10. Phytoremediation potential of maize (Zea mays L.) in co-contaminated soils with pentachlorophenol and cadmium.

    Science.gov (United States)

    Hechmi, Nejla; Ben Aissa, Nadhira; Abdennaceur, Hassen; Jedidi, Naceur

    2013-01-01

    The ubiquitous coexistence of heavy metals and organic contaminants was increased in the polluted soil and phytoremediation as a remedial technology and management option is recommended to solve the problems of co-contamination. Growth of Zea mays L and pollutant removal ability may be influenced by interactions among mixed pollutants. Pot-culture experiments were conduced to investigate the single and interactive effect of cadmium (Cd) and pentachlorophenol (PCP) on growth of Zea mays L, PCP, and Cd removal from soil. Growth response of Zea mays L is considerably influenced by interaction of Cd and PCP, significantly declining with either Cd or PCP additions. The dissipation of PCP in soils was notably affected by interactions of Cd, PCP, and plant presence or absence. At the Pentachlorophenol in both planted and non-planted soil was greatly decreased at the end of the 10-week culture, accounting for 16-20% of initial extractable concentrations in non-planted soil and 9-14% in planted soil. With the increment of Cd level, residual pentachlorophenol in the planted soil tended to increase. The pentachlorophenol residual in the presence of high concentration of Cd was even higher in the planted soil than that in the non-planted soil.

  11. Iron oxide nanoparticles coated with β-cyclodextrin polluted of Zea mays plantlets

    Directory of Open Access Journals (Sweden)

    Mihaela Racuciu

    2012-01-01

    Full Text Available The present experimental investigation is focused on the study of assimilatory pigments and nucleic acid levels in young plants intended for agricultural use (Zea mays in presence of water based magnetic fluid added in culture medium. The magnetic fluid was constituted by coating the nanosized magnetic nanoparticles (with 10.55 nm average value of the physical diameter with β-cyclodextrin (C42H70O35 and further dispersion in water. After germination, various volume fractions (between 10 mL/L and 500 mL/L of the magnetic fluid was added daily in the culture medium of Zea mays plants still at their early ontogenetic stages. Toxicity symptoms leaded to brown spots covering the leaf surface for the highest magnetic fluid volume fractions used, a putative oxidative stress generated by iron excess treatment. Relatively small volume fraction of magnetic fluid solutions induced the increase of chlorophyll a level (up to 38%, the main photosynthesis pigment, as well that the nucleic acid level (up to 57% in Zea mays plantlets. All volume fractions of magnetic fluid solutions analyzed may have severe disruptive effects such as the ratio chlorophyll a/chlorophyll b (about 50% decreasing.

  12. Todo sobre el neobarroco

    Directory of Open Access Journals (Sweden)

    Arturo Carrera

    2007-07-01

    Full Text Available Lo que hemos escuchado y atendido hasta aquí, hoy, ayer, sobre todo en la propuesta poética esbozada por Sergio Raimondi en su ensayo sobre Aldo Oliva, demuestra que las singularidades, su pasión, anulan subrepticiamente las nominaciones.Anoche en la televisión una orquesta sinfónica y un coro numeroso. Súbitamente, me hubiera gustado ser uno de esos intérpretes solitarios para sí, a pesar de la armonía, anónimos, a pesar del brillo sonoro… un violín, un triángulo… apenas… tres grillos… como ...

  13. Resumen estudios sobre tabaquismo

    OpenAIRE

    Gónzalez, M.M. (M.)

    2009-01-01

    Este documento se realizó para publicar en la página Web de la Gerencia de Atención primaria del Área III. Este documento es una recopilación de estudios sobre tabaquismo. Gerencia de Atención Primaria Área III

  14. Effect of emamectin benzoate on mortality, proboscis extension, gustation and reproduction of the corn earworm, Helicoverpa zea.

    Science.gov (United States)

    López, Juan D; Latheef, M A; Hoffmann, W C

    2010-01-01

    Newly emerged corn earworm adults, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) require a carbohydrate source from plant or other exudates and nectars for dispersal and reproduction. Adults actively seek and forage at feeding sites upon eclosion in the habitat of the larval host plant or during dispersal to, or colonization of, a suitable reproductive habitat. This nocturnal behavior of H. zea has potential for exploitation as a pest management strategy for suppression using an adult feeding approach. This approach entails the use of a feeding attractant and stimulant in combination with a toxicant that when ingested by the adult will either reduce fecundity/fertility at sub-lethal dosages or kill the adult. The intent of this study was to assess reproductive inhibition and toxicity of emamectin benzoate on H. zea when ingested by the adults when mixed in ppm active ingredient (wt:vol) with 2.5 M sucrose as a feeding stimulant. Because the mixture has to be ingested to function, the effect of emamectin benzoate was also evaluated at sub-lethal and lethal concentrations on proboscis extension and gustatory response of H. zea in the laboratory. Feral males captured in sex pheromone-baited traps in the field were used for toxicity evaluations because they were readily available and were more representative of the field populations than laboratory-reared adults. Laboratory-reared female moths were used for reproduction effects because it is very difficult to collect newly emerged feral females from the field. Emamectin benzoate was highly toxic to feral H. zea males with LC(50) values (95% CL) being 0.718 (0.532-0.878), 0.525 (0.316-0.751), and 0.182 (0.06-0.294) ppm for 24, 48 and 72 h responses, respectively. Sub-lethal concentrations of emamectin benzoate did not significantly reduce proboscis extension response of feral males and gustatory response of female H. zea. Sublethal concentrations of emamectin benzoate significantly reduced percent larval hatch of

  15. VIGOR DE SEMENTES DE MILHO (Zea mays L. AVALIADO PELA PRECOCIDADE DE EMISSÃO DA RAIZ PRIMÁRIA EVALUATION OF CORN (Zea mays L. SEED VIGOR THROUGH THE PRECOCITY OF PRIMARY ROOT EMISSION

    Directory of Open Access Journals (Sweden)

    Francisco Ferraz de Toledo

    1999-01-01

    Full Text Available Foi desenvolvido trabalho baseado na determinação da precocidade da emissão da raiz primária de sementes de milho, em dez lotes de um mesmo cultivar. Este processo constou da distribuição de 200 sementes de cada lote sobre folhas de papel umedecido e, também, rolos de papel, que permaneceram em germinador a 25 °C; de 12 em 12 horas, aquelas que apresentaram emissão da raiz primária foram removidas, contadas e anotadas. Para estabelecer comparação entre os métodos e os lotes, paralelamente, as sementes eram avaliadas através da determinação do grau de umidade, dos testes de germinação e de vigor (primeira contagem, teste de frio com solo e emergência de plântulas em campo. Concluiu-se que há possibilidade de se utilizar o teste de emissão da raiz primária, em rolos de papel, para a avaliação do vigor de sementes de milho.The objectives of this study were to evaluate the variability of the emission of seed radicle of corn (Zea mays L. and to establish indexes of primary root emission to test the vigor of commercial seed lots. Samples of corn seeds not treated with fungicides, were taken from ten lots of the same cultivar. Two hundred seeds from each lot were distributed on wetted paper towels and also within paper rolles at 25 °C. Each 12 hours, seeds with primary root emission were counted and removed. Indexes of primary root emission were calculated and compared to conventional laboratory tests (first count; accelerated aging; cold test and field emergence. It was concluded that the primary root emission test, in rolled paper towels can be of great value for evaluating the vigor of corn seeds.

  16. Tesis sobre municipalismo libertario

    OpenAIRE

    Bookchin, Murray

    2014-01-01

    Históricamente, la teoría y la práctica social radical se han centrado sobre dos campos de la actividad social humana: el lugar de trabajo y la comunidad. A partir de la creación del Estado-nación y de la Revolución Industrial, la economía ha ido adquiriendo una posición predominante sobre la comunidad; y no sólo en la ideología capitalista, sino también en los diferentes socialismos, libertarios y autoritarios, que han ido apareciendo en el último siglo. Este cambio de posición del socialism...

  17. Escrito sobre el cuerpo

    Directory of Open Access Journals (Sweden)

    Antonio Malalana Ureña

    2013-09-01

    Full Text Available El catálogo, en una edición bilingüe español-inglés, es una pequeña guía de la exposición Shirin Neshat. Escrito sobre el cuerpo, muestra que se integra dentro de los actos de PHOTOESPAÑA13, el festival internacional de fotografía y artes visuales. El esquema del libro es sencillo y los textos son extremadamente divulgativos. El primero de ellos, Escrito sobre el cuerpo (pp. 10-15, cuyo autor es Octavio Zaya, comisario de la exposición, resume la trayectoria de esta intelectual, que "interactúa" con la fotografía y los formatos audiovisuales, y nos presenta la argumentación narrativa de los documentos expuestos, contextualizando la obra recopilada.

  18. Inferencias sobre Grafos

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    Sira M. Allende

    2002-05-01

    Full Text Available El estudio de un juego puede ser modelado asumiendo que solo algunas partidas son observadas. Entonces el árbol del juego debe ser estimado utilizando información muestral. Similarmente ocurre al obtener información sobre el comportamiento de las decisiones tomadas por individuos muestreados sobre un árbol de decisión teórico. Al considerar una medida de probabilidad que caracterice el comportamiento de redes aleatorias se puede obtener un estimado del árbol asociado. Este problema es el analizado en este trabajo. Algunos resultados experimentales obtenidos usando Recocido Simulado ilustran el procedimiento. Su papel en el estudio de modelos económicos y de mercadeo es discutido.

  19. Caracterização da atividade amilásica do malte de milho (Zea mays L. = Characterization of amylase activity from maize (Zea mays L. malt

    Directory of Open Access Journals (Sweden)

    Joana Paula Menezes Biazus

    2006-01-01

    Full Text Available Este trabalho objetivou estudar o processo de germinação e a caracterização da atividade bioquímica das amilases do malte de milho (Zea mays L. para gerar uma fonte de amilase de baixo custo e boa atividade enzimática. A atividade enzimática foi monitorada todos os dias durante a germinação das sementes para se obter a melhor condição de produção do malte. Os resultados mostraram que a atividade enzimática nas sementes foi maior no 4º. dia de germinação. A caracterização bioquímica mostrou que as amilases do malte apresentam faixa ótima de pH entre 4,3 e 6, com temperaturas ótimas a 50°C e 80ºC e os valores de Km e Vmax para hidrólise do amido foram de 7,69.10-2 g/L e 7,69.102g/L.min, respectivamente.This work aimed to study the germination process and characterization of the amylolytic activity of the maize (Zea mays L. malt aiming to obtain source amylases at lower cost. Enzymatic activity was monitored all days during the seed germination, for obtaining thebest condition of malt production. Results showed that the enzymatic activity from maize seeds was larger in 4° germination day. Enzymes characterization showed that the maize malt amylases have optimal zone of pH between 4.3 and 6, with optimal temperatures of 50°C and 80ºC. The Km and Vmax values for starch hydrolysis were 7.69.10-2 g/L and 7.69.102g/L.min, respectively.

  20. Recovery of Lead(II from Aqueous Solutions by Zea mays Tassel Biosorption

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    Caliphs M. Zvinowanda

    2010-01-01

    Full Text Available Problem statement: Major adsorbent materials used in heavy metal ion removal from polluted aqueous streams are expensive and difficult to regenerate. In this study, the possibility of using Zea mays tassel, as an alternative low cost biosorbent material to remediate heavy metal pollution was investigated. Lead (II was used because of its wide application in industrial products and well documented toxicity. Approach: Tassel was obtained from mature Zea mays cultivar R52 hybrid plants. The tassel was milled to a powder and was used to adsorb lead(II ions from simulated solutions in batch experiments. The desorption of lead(II was carried out using nitric acid and sodium citrate solutions. The adsorbent was characterized by FTIR, EDX and ESCA before and after application of lead(II solutions. Results: For samples with concentrations of 100 mg L-1 Pb(II, 94-98% was adsorbed and 57-74 and 57-67% recoveries were achieved with 0.5-5 M nitric acid and 0.01-0.2 M sodium citrate as the stripping solutions, respectively. EDX spectrum of pure tassel indicated that group 1 and 2 metals were the major exchangeable ions present on its surface. ESCA analysis picked up small amounts of lead(II in the form of Pb(OH+ and Pb(NH+ ions on the surface of tassel adsorbent exposed to Pb2+ ions and none on pure tassel sample. Functional groups such as -H, -NH2, -C = O and -COOH which are polar and are legends which are capable of binding heavy metals were identified by FTIR. Conclusion: The potential of Zea mays tassel to adsorb and recover heavy metals from aqueous solution was successfully demonstrated with Pb(II sample solutions. The results obtained thus far demonstrated the possibility of using tassel powder in the removal as well as recovery of metals from aqueous solutions.

  1. THE INFLUENCE OF GRAMOXONE HERBICIDE ON THE CONTENT OF THE PHOTOSYNTHETIC PIGMENTS IN ZEA MAYS

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    Antoanela Patras

    2007-08-01

    Full Text Available The active substance of Gramoxone herbicide is interacting with plant’s photosynthetic systems, playing the role of final acceptor of the photosynthetic electrons. Except this known mode of action, it has been also observed the inhibitory action on the protoporphyrinogen oxidase – essential enzyme for chlorophylls biosynthesis, and also the decrease of photosynthetic pigment’s concentration in some spontaneous plants. Based on these prerequisites, the present study demonstrates the decrease of the photosynthetic pigment’s content in Zea mays in the presence of Gramoxone.

  2. Salmon silk genes contribute to the elucidation of the flavone pathway in maize (Zea mays L.).

    Science.gov (United States)

    McMullen, M D; Kross, H; Snook, M E; Cortés-Cruz, M; Houchins, K E; Musket, T A; Coe, E H

    2004-01-01

    We utilized maize (Zea mays L.) lines expressing the salmon silk (sm) phenotype, quantitative trait locus analysis, and analytical chemistry of flavone compounds to establish the order of undefined steps in the synthesis of the flavone maysin in maize silks. In addition to the previously described sm1 gene, we identified a second sm locus, which we designate sm2, located on the long arm of maize chromosome 2. Our data indicate that the sm1 gene encodes or controls a glucose modification enzyme and sm2 encodes or controls a rhamnosyl transferase. The order of intermediates in the late steps of maysin synthesis was established as luteolin --> isoorientin --> rhamnosylisoorientin --> maysin.

  3. Cytogenetics of monosomes in Zea mays. Comprehensive report, October 1, 1970--January 31, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Weber, D. F.

    1976-10-01

    Monosomics (organisms lacking one chromosome) are perhaps the most interesting of the aneuploid types because a chromosome lacks a pairing partner in each meiotic cell and because genes on an entire chromosome are present in the hemizygous condition in each meiotic cell. A recently-discovered system produces a high frequency of monosomics in a Zea mays (maize). With this system, monosomics are available in a diploid organism in relatively large numbers and for most of the chromosomes for the first time. Results are reported from studies on several aspects of the cytogenetics of monosomics.

  4. Zinc toxicity on antioxidative response in (Zea mays L. at two different pH

    Directory of Open Access Journals (Sweden)

    Hosseini, Zahra

    2013-02-01

    Full Text Available Zn is the second most abundant transition metal after iron (Fe. Excess Zn can have negative effects on plants. The effect of Zn at two different pH on lipid peroxidation (MDA, membrane permeability (EC, hydrogen peroxide (H2O2,non-protein thiols (NPT and the activities of major antioxidant enzymes Zea mays were investigated under controlled growth conditions. Zn-excess conditions increased the EC, MDA, H2O2 content and non-protein thiols and also activities of antioxidant enzymes were increased. Also zinc toxicity was higher in 4.5 pH than 7.5 pH.

  5. Puente sobre el Rin

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    Gortz, Wilhelm

    1961-12-01

    Full Text Available Del total de 35 proyectos presentados al concurso del puente para carretera sobre el Rin, entre Duisburg-Ruhrort y Homberg, sólo dos proposiciones de la Demag fueron consideradas: Una con tablero suspendido por vientos que parten de dos torres, y otra, con suspensión por cables flexibles que se apoyan en dos torres y anclaje en la misma estructura. Por razones netamente estéticas fue elegida la propuesta Demag de puente suspendido por cables, aunque la solución con vientos hubiera sido la más económica, teniendo en cuenta las condiciones existentes.

  6. Saber sobre la radio

    OpenAIRE

    Mata, María Cristina; Universidad Nacional de Córdoba. Argentina

    1998-01-01

    La autora propone en este artículo repensar los fundamentos sobre los cuales se estructuran las asignaturas y talleres de radio en las escuelas de Comunicación Social en Latinoamérica, con el proposito de romper la escisión  entre teoría/práctica y de no violentar su complejidad: en la radio, entendida como práctica comunicativa, se juega en primer lugar una "red de vinculaciones e intercambios" en condiciones privilegiadas para la dialoguicidad. En un segundo lugar, asociado al desarrollo de...

  7. Excertos sobre o sedentarismo

    OpenAIRE

    Alexandre Palma; Murilo Mariano Vilaça; Monique Ribeiro de Assis

    2014-01-01

    O sedentarismo tem sido tratado como algo perfeitamente determinável, objetivo e, portanto, que pode ser apreendido. Por outro lado, o conceito de sedentarismo ainda permanece questionável e, por conseguinte, os instrumentos mostram-se inconsistentes. Neste sentido, o objetivo do presente estudo foi mostrar que diferentes discursos de verdade vêm concorrendo por esse conceito, o que nos motiva a pensar qual é a verdade ou, até mesmo, se há alguma verdade sobre ele. Após apresentarmos diferent...

  8. Effects of Different Nitrogen Application Strategies on Yield and ForageNutritive Quality of Zea mexicana

    Institute of Scientific and Technical Information of China (English)

    WANGYong-jun; WANGKong-jun; YUANCui-ping; XUHong

    2004-01-01

    A pool experiment was carried out to study the effects of different nitrogen application strategies (rates and stages of nitrogen application) on yield and forage nutritive quality of Zea mexicana cultivated in summer, 2002. In the whole growing stage, its stem was clipped three times at the height of 25 cm when it was II0 cm high (H1, H2 and H3 stand for the first, second and third harvest stage, respectively). Six indexes including crude protein (CP), ether extract (EE), nitrogen free extract (NFE), acid detergent fiber (ADF), crude ash (CA), and general energy (GE) were employed to evaluate the forage nutritive value. The results showed that the content of CP and EE increased but the content of CA and ADF decreased under the two nitrogen rates (High-rate N, 600 kg ha-1;Mid-rate N, 300 kg ha-1). The fresh and dry harvest biomass of the whole plants on H1 and those of the leaves on H2 were also improved. But the stalks on H2 and the whole plants on H3 were affected mainly by dressing nitrogen fertilizer. The yield of CP and EE, CA,NFE, and GE was mainly affected by nitrogen rates. The ADF yield increased was due to the increment of the fresh and dry harvest biomass. Nitrogen applied as base fertilizer for summer Zea mexicana can be harvested a higher biomass and improve the forage nutritive quality.

  9. De novo assembly ofZea nicaraguensis root transcriptome identiifed 5261full-length transcripts

    Institute of Scientific and Technical Information of China (English)

    JIANG Wei; LIU Hai-lan; WU Yuan-qi; ZHANG Su-zhi; LIU Jian; LU Yan-li; TANG Qi-lin; RONG Ting-zhao

    2016-01-01

    Zea nicaraguensis, a wild relative of cultivated maize (Zea mayssubsp. mays), is considered to be a valuable germplasm to improve the waterlogging tolerance of cultivated maize. Use of reverse genetic-based gene cloning and function veriif-cation to discover waterlogging tolerance genes inZ. nicaraguensis is currently impractical, because little gene sequence information forZ. nicaraguensis is available in public databases. In this study,Z. nicaraguensis seedlings were subjected to simulated waterlogging stress and total RNAs were isolated from roots stressed and non-stressed controls. In total, 80 mol L–1 Ilumina 100-bp paired-end reads were generated.De novo assembly of the reads generated 81002 ifnal non-re-dundant contigs, from which 5261 full-length transcripts were identiifed. Among these full-length transcripts, 3169 had at least one Gene Ontology (GO) annotation, 2354 received cluster of orthologous groups (COG) terms, and 1992 were assigned a Kyoto encyclopedia of genes and genomes (KEGG) Orthology number. These sequence data represent a valuable resource for identiifcation ofZ. nicaraguensisgenes involved in waterlogging response.

  10. IDENTIFICATION OF LECTINS OF ZEA MAYS RAW MATERIAL AND THE STUDY OF LECTIN ACTIVITY

    Directory of Open Access Journals (Sweden)

    Karpiuk UV

    2013-03-01

    Full Text Available The aime of the study was to identify lectins in the Zea mays raw material: roots, stems, heads, leaves and corn silk and study their activity. Lectins activity has been studied using the biological method of ratuserytroagglutination. This method is based on formation of aggregates of lectins and rats erythrocytes. The activity unit was the floor amount of lectins that agglutinate erythrocytes. The protein nature of extracts that agglutinate has been determined using Bradford method. The lectins activity of Zea mays roots was 6,21±0,11 unit/mg of protein; of heads – 2,61±0,17 unit/mg of protein; of leaves – 0,62 ±0,05 unit/mg of protein; of corn silk – 1,06±0,08 unit/mg of protein; of stems – 0,97±0,09 unit/mg of protein. The greatest lectins activity was in leaves, stems and corn silk.

  11. Analysis of the Genome of the Sexually Transmitted Insect Virus Helicoverpa zea Nudivius 2

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    Zhiqiang Lu

    2012-01-01

    Full Text Available The sexually transmitted insect virus Helicoverpa zea nudivirus 2 (HzNV-2 was determined to have a circular double-stranded DNA genome of 231,621 bp coding for an estimated 113 open reading frames (ORFs. HzNV-2 is most closely related to the nudiviruses, a sister group of the insect baculoviruses. Several putative ORFs that share homology with the baculovirus core genes were identified in the viral genome. However, HzNV-2 lacks several key genetic features of baculoviruses including the late transcriptional regulation factor, LEF-1 and the palindromic hrs, which serve as origins of replication. The HzNV-2 genome was found to code for three ORFs that had significant sequence homology to cellular genes which are not generally found in viral genomes. These included a presumed juvenile hormone esterase gene, a gene coding for a putative zinc-dependent matrix metalloprotease, and a major facilitator superfamily protein gene; all of which are believed to play a role in the cellular proliferation and the tissue hypertrophy observed in the malformation of reproductive organs observed in HzNV-2 infected corn earworm moths, Helicoverpa zea.

  12. Knob-associated tandem repeats on mitotic chromosomes in maize, Zea diploperennis and their hybrids

    Institute of Scientific and Technical Information of China (English)

    XIONG Zhiyong; GAO Yuan; HE Guanyuan; GU Mingguang; GUO Lequn; SONG Yunchun

    2004-01-01

    Knob-associated tandem repeats, 180-bp repeats and TR-1 elements, together with 45S rDNA were located on mitotic chromosomes of Zea diploperennis (DP),maize inbred line F102 and their hybrid. In DP, knobs on the short arm of chromosomes 1 and 4 and on the long arm of the chromosomes 4 and 5 are composed predominantly of the 180-bp repeats. In addition, 180-bp repeats existed together with TR-1 elements were also detected on the short arm of chromosomes 2 and 5 and on the long arm of the chromosomes 2, 6, 7, 8 and 9. In maize inbred line F102, 180-bp repeats were present in chromosomes 7S and one homologue of chromosomes 8L. TR-1 elements appeared on satellite of chromosome 6 and no detectable hybridization site co-located with 180-bp repeats was observed in maize F102. Polymorphism of size, number, and distribution of 180-bp and TR-1 signals were revealed among different chromosomes in these two species and heteromorphism existed between some homologous chromosomes in the same species.Using these excellent landmarks, the interspecific hybrid of maize and DP were identified. The results suggest that comparative analysis of 180-bp repeats and TR-1 elements may help understand the genome organization and the evolution in Zea.

  13. Chromium accumulation potential of Zea mays grown under four different fertilizers.

    Science.gov (United States)

    Dheeba, B; Sampathkumar, P; Kannan, K

    2014-12-01

    Chromium (Cr) contamination in soil is a growing concern in sustainable agriculture production and food safety. We performed pot experiment with chromium (30 mg/soil) to assess the accumulation potential of Zea mays and study the influence of four fertilizers, viz. Farm Yard Manure (FYM), NPK, Panchakavya (PK) and Vermicompost (VC) with respect to Cr accumulation. The oxidative stress and pigment (chlorophyll) levels were also examined. The results showed increased accumulation of chromium in both shoots and roots of Zea mays under FYM and NPK supply, and reduced with PK and VC. While the protein and pigment contents decreased in Cr treated plants, the fertilizers substantiated the loss to overcome the stress. Similarly, accumulation of Cr increased the levels of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) indicating the enhanced damage control activity. However, these levels were relatively low in plants supplemented with fertilizers. Our results confirm that the maize can play an effective role in bioremediation of soils polluted with chromium, particularly in supplementation with fertilizers such as farm yard manure and NPK.

  14. Effects of Different Nitrogen Application Strategies on Yield and Forage Nutritive Quality of Zea mexicana

    Institute of Scientific and Technical Information of China (English)

    WANG Yong-jun; WANG Kong-jun; YUAN Cui-ping; XU Hong

    2004-01-01

    A pool experiment was carried out to study the effects of different nitrogen application strategies (rates and stages of nitrogen application) on yield and forage nutritive quality of Zea mexicana cultivated in summer, 2002. In the whole growing stage, its stem was clipped three times at the height of 25 cm when it was 110 cm high (H1, H2 and H3 stand for the first, second and third harvest stage, respectively). Six indexes including crude protein (CP), ether extract (EE), nitrogen free extract (NFE), acid detergent fiber (ADF), crude ash (CA), and general energy (GE) were employed to evaluate the forage nutritive value. The results showed that the content of CP and EE increased but the content of CA and ADF decreased under the two nitrogen rates (High-rate N, 600 kg ha-1;Mid-rate N, 300 kg ha-1). The fresh and dry harvest biomass of the whole plants on H1 and those of the leaves on H2 were also improved. But the stalks on H2 and the whole plants on H3 were affected mainly by dressing nitrogen fertilizer. The yield of CP and EE, CA,NFE, and GE was mainly affected by nitrogen rates. The ADF yield increased was due to the increment of the fresh and dry harvest biomass. Nitrogen applied as base fertilizer for summer Zea mexicana can be harvested a higher biomass and improve the forage nutritive quality.

  15. Sobre historia mundial hoy

    Directory of Open Access Journals (Sweden)

    Vera Weiler

    2010-08-01

    Full Text Available Los procesos de globalización son una realidad; su enorme impacto sobre la vida humana los ha convertido en un tema recurrente sobre el que se escribe y se comenta a diario también en Colombia. Los libros que de ellos tratan, ante todo los que 10 hacen en tono crítico, baten records en la industria editorial en todo el mundo. Las expectativas que acerca del futuro abrigan cientos de millones de personas se relacionan con 10 que ellas esperan, para bien o para mal, de la globalización. Las posturas que los gobernantes ocupan al respecto en el mundo son, cuando menos de aceptación, generalmente de activa participación en pos de la globalización. Por un lado, crece la preocupación y se multiplican las protestas; por el otro, dominan los razonamientos de los especialistas en materia de maximización de los rendimientos de los capitales que presentan la globalización, al estilo que se viene imponiendo, como el camino ineludible del gobierno universal de la eficiencia. ¿Tienen que decir algo los historiadores frente a todo esto?.

  16. Sobre la tragedia griega

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    Mauricio Vélez Upegui

    2015-01-01

    Full Text Available Luego de caracterizar la tragedia griega clásica como expresión de un arte ciudadano que participa por igual de un carácter festivo, cierto régimen discursivo y una clara inscripción físico-espacial, el texto se demora en considerar tres aspectos fundamentales de esta forma dramática inventada por los griegos, a saber: una exposición sobre las fuentes orales míticas de las que los autores echan mano para componer la historia de cada una de las piezas que son llevadas a escena al amparo de un espíritu agonal; una explicación del funcionamiento formal de la tragedia, basado en la alternancia de partes cantadas (coro y partes recitadas (héroe; y, finalmente, una acotación sobre el sentido –interno y externo– que la acción dramática posee, en tanto elemento articulador de la trama.

  17. Cinética de rehidratación y deterioro biológico en Zea mays almacenado a una Humedad Relativa del Aire Intergranular (HRAI del 92%

    Directory of Open Access Journals (Sweden)

    Eguiazu, G. M.

    1993-12-01

    Full Text Available Maize grains (Zea mays var indurata «Plata» tipe destined to commercialization were submitted to a relative humidity of the intergranular air of 92% during 120 days to 25 °C. The kinetics of rehydration, humidity and biological damage («mouldy» «blue eye» and «spoiled» was determined. After 14 to 17 days, the sample rehydrates on the basis of commercialization of 14,5% of humidity and in the same period a degree of standard of commercial quality is lost. It is established that the basis of commercialization of 14,5% is very near the limit which favours the biological damage.Granos de maíz (Zea mays var. indurata tipo «Plata», destinado a comercialización, fueron sometidos a una Humedad Relativa del Aire Intergranular del 92% a 25 °C durante 120 días. Se determinó la cinética de rehidratación, humedad y el deterioro biológico («Verdín» y «Dañado». Se observó que luego de 14 a 17 días la muestra se rehidrató por sobre la base de comercialización del 14,5% de humedad y en el mismo periodo se pierde un grado en el estandard de calidad comercial. Se plantea que la base de comercialización del 14,5% se halla muy cercana al límite que favorece el deterioro biológico.

  18. Selection and adaptation to high plant density in the Iowa Stiff Stalk synthetic maize (Zea mays L.) population

    Science.gov (United States)

    The plant density at which Zea mays L. hybrids achieve maximum grain yield has increased throughout the hybrid era while grain yield on a per plant basis has increased little. Changes in plant traits including grain yield, moisture, test weight, and stalk and root lodging have been well characterize...

  19. Effect of emamectin benzoate on mortality, proboscis extension, gustation and reproduction of the corn earworm, Helicoverpa zea

    Science.gov (United States)

    Newly emerged bollworm adults, Helicoverpa zea (Boddie) require carbohydrate source from plant exudates and nectars for reproduction. Adults actively seek such feeding sites upon eclosion in their natural habitat. We wanted to evaluate this nocturnal behavior of the bollworm for potential use as a p...

  20. Water management options based on rainfall analysis for rainfed maize (Zea Mays L.) production in Rushinga district Zimbabwe

    NARCIS (Netherlands)

    Nyakudya, I.W.; Stroosnijder, L.

    2011-01-01

    Maize (Zea mays L.), the dominant and staple food crop in Southern and Eastern Africa, is preferred to the drought-tolerant sorghum and pearl millet even in semi-arid areas. In semi-arid areas production of maize is constrained by droughts and poor rainfall distribution. The best way to grow crops i

  1. 玉米低磷胁迫研究现状%Research Situation of Low Phosphorus Stress in Zea mays

    Institute of Scientific and Technical Information of China (English)

    湛静; 陈发波

    2014-01-01

    玉米是世界第二大粮食作物,同时也是我国第一大农作物。磷是玉米生长发育所必需的元素之一,充当生物膜和核酸的重要组成元素,缺磷将严重影响玉米的生长发育。综述了缺磷对玉米苗期性状、根系、生理生化特性及产量等方面的影响。%Zea mays is not only the second largest food crops in the world ,but also the first major crops in China.Phosphorus ,one of the essential elements making up biofilm and nucleic acid ,is indispensable to Zea mays.Phosphorus deficiency will affect growth and development of Zea mays.This article summarized the effects of low phosphorus stress on seedling traits ,root,physiological and biochemistry characteristics ,and yield in Zea mays.

  2. TOXICITY OF METHYL-TERT BYTYL ETHER (MTBE) TO PLANTS (AVENA SATIVA, ZEA MAYS, TRITICUM AESTIVUM, AND LACTUCA SATIVA)

    Science.gov (United States)

    Effects of Methyl tert-butyl ether (MTBE) on the germination of seeds and growth of the plant were studied in some laboratory experiments. Test plants were wild oat (Avena sative), sweet corn (Zea mays), wheat (Triticum aestivum), and lettuce (Lactuca sativa). Seed germination,...

  3. Embryogenesis in Zea mays L. A structural approach to maize caryopsis development in vivo and in vitro.

    NARCIS (Netherlands)

    Lammeren, van A.A.M.

    1987-01-01

    In this thesis the embryological development of the maize plant ( Zeamays L.) is described. The investigations aim at analysing the development of polarity, the initiation of meristems, the differentiation of tissues within the embryo and the interaction between the embryo and the extr

  4. Promoting Student Inquiry Using "Zea Mays" (Corn) Cultivars for Hypothesis-Driven Experimentation in a Majors Introductory Biology Course

    Science.gov (United States)

    Blair, Amy C.; Peters, Brenda J.; Bendixen, Conrad W.

    2014-01-01

    The AAAS Vision and Change report (2011) recommends incorporating student research experiences into the biology curriculum at the undergraduate level. This article describes, in detail, how "Zea mays" (corn) cultivars were used as a model for a hypothesis-driven short-term research project in an introductory biology course at a small…

  5. Molecular and biochemical analysis of the plastidic ADP-glucose transporter (ZmBT1) from Zea mays.

    NARCIS (Netherlands)

    Kirchberger, S.; Leroch, M.; Huynen, M.A.; Wahl, M.; Neuhaus, H.E.; Tjaden, J.

    2007-01-01

    Physiological studies on the Brittle1 maize mutant have provided circumstantial evidence that ZmBT1 (Zea mays Brittle1 protein) is involved in the ADP-Glc transport into maize endosperm plastids, but up to now, no direct ADP-Glc transport mediated by ZmBT1 has ever been shown. The heterologous synth

  6. Molecular and biochemical analysis of the plastidic ADP-glucose transporter (ZmBT1) from Zea mays

    NARCIS (Netherlands)

    Kirchberger, S.; Leroch, M.; Huynen, M.A.; Wahl, M.; Neuhaus, H.E.; Tjaden, J.

    2007-01-01

    Physiological studies on the Brittle1 maize mutant have provided circumstantial evidence that ZmBT1 (Zea mays Brittle1 protein) is involved in the ADP-Glc transport into maize endosperm plastids, but up to now, no direct ADP-Glc transport mediated by ZmBT1 has ever been shown. The heterologous synth

  7. NUTRITIVE VALUE OF MAIZE (Zea Mays AND DOLECOUS (Lablab Purpureus AS AFFECTED BY PHOSPHOROUS FERTILIZATION AND INTERCROPPING

    Directory of Open Access Journals (Sweden)

    E.O. AMASAIB

    2012-11-01

    Full Text Available A field experiment was conducted at the Demonstration Farm of University of Khartoum to determine the effect of phosphorous fertilization and intercropping on the nutritive value of Zea mays and Lablab purpureus. The field experiment was arranged as Split Plot Design with four replications. The main plots were (Lablab purpureus as sole crop, Zea mays as sole crop, Lablab purpureus and Zea mays in the mixture. The sub plot treatments were phosphorous fertilization at the rate of (0, 50 and 75 kg P2O5 / ha which were then referred to as P0, P1 and P2 respectively. The plants measured were Lablab purepureus as pure stand, Lablab purepureus in the mixture, Zea mays as the pure stand and the Zea mays in the mixture. Samples of 45 days cut from sowing were used to assess the ash, crude protein (CP, ether extracts (EE, crude fiber (CF, neutral detergent fibre (NDF and dry matter digestibility. The data were statistically analyzed using complete randomized design. The results revealed that intercropping and phosphorous fertilization caused a significant (P<0.05 increased on the CP content and dry matter digestibility of all forages under estimation. Intercropping and phosphorous fertilization caused slight increase on the Ash content for all crops in this study. Moreover, Intercropping and phosphorous fertilization caused a decrease on the CF and NDF content of all forages under estimation but with no significant difference. However, Intercropping caused non–significant effect (P<0.05 on the EE content of Zea mays while, intercropping had a positive influence (P<0.05 on the EE content of Lablab purpureus. The data obtained indicated that phosphorous fertilization caused non–significant effect on the EE content of all crops in this study (P<0.05 except Lablab purpureus in the mixture with Zea mays which increased significantly (P<0.05 by increasing phosphorous level. It can be concluded that intercropping and phosphorous fertilization improved the

  8. Excertos sobre o sedentarismo

    Directory of Open Access Journals (Sweden)

    Alexandre Palma

    2014-09-01

    Full Text Available O sedentarismo tem sido tratado como algo perfeitamente determinável, objetivo e, portanto, que pode ser apreendido. Por outro lado, o conceito de sedentarismo ainda permanece questionável e, por conseguinte, os instrumentos mostram-se inconsistentes. Neste sentido, o objetivo do presente estudo foi mostrar que diferentes discursos de verdade vêm concorrendo por esse conceito, o que nos motiva a pensar qual é a verdade ou, até mesmo, se há alguma verdade sobre ele. Após apresentarmos diferentes possibilidades de compreender o sedentarismo, através do uso de aforismos, entendemos que postular um discurso como verdade talvez apenas signifique que as pessoas nele creem e que há uma vontade de verdade como uma vontade voltada para o poder.

  9. Sobre el Portugal ilustrado

    OpenAIRE

    Santolaya Heredero, Laura

    1992-01-01

    El mismo título invita a preguntarse, a modo de introducción, en qué consistió la Ilustración en Portugal. Me refiero a las prácticas, sin pretender entrar en un debate filosófico. Desde luego, las prácticas políticas y económicas de los Estados del XVIII poco tuvieron que ver con las ideas de los filósofos de la Ilustración. El fenómeno de la Ilustración se aprovechió de una propaganda anecdótica para hacer suponer a los lectores de libros sobre ella que en los diversos ...

  10. Sobre multifunciones Fuzzy

    Directory of Open Access Journals (Sweden)

    Renato César Scarparo

    2002-01-01

    Full Text Available En este trabajo se presentan y demuestran algunos resultados de D.T. Luc y C, Vargas referentes a multifunciones con dominio y blanco en espacios vectoriales topológicos de Hausdorff sobre R, como así mismo se explícita el concepto de multifunción fuzzy de acuerdo a Papageogiou, y se demuestran dos teorema de S. S. Chag, con respecto a las multifunciones fuzzy, proposiciones todas estas, que integran una línea de resultados necesarios para la demostración de desigualdades variacionales para multifunciones fuzzy, a su vez necesarias, para la extensión fuzzy de conocido teorema de Walras.

  11. Bt Maize Seed Mixtures for Helicoverpa zea (Lepidoptera: Noctuidae): Larval Movement, Development, and Survival on Non-transgenic Maize.

    Science.gov (United States)

    Burkness, Eric C; Cira, T M; Moser, S E; Hutchison, W D

    2015-12-01

    In 2012 and 2013, field trials were conducted near Rosemount, MN, to assess the movement and development of Helicoverpa zea (Boddie) larvae on non-Bt refuge corn plants within a seed mixture of non-Bt and Bt corn. The Bt corn hybrid expressed three Bt toxins-Cry1Ab, Cry1F, and Vip3A. As the use of seed mixtures for insect resistance management (IRM) continues to be implemented, it is necessary to further characterize how this IRM approach impacts resistance development in ear-feeding Lepidopteran pests. The potential for Bt pollen movement and cross pollination of the non-Bt ears in a seed mixture may lead to Bt toxin exposure to larvae developing on those refuge ears. Larval movement and development by H. zea, feeding on non-Bt refuge plants adjacent to either transgenic Bt or non-Bt plants, were measured to investigate the potential for unintended Bt exposure. Non-Bt plants were infested with H. zea eggs and subplots were destructively sampled twice per week within each treatment to assess larval development, location, and kernel injury. Results indicate that H. zea larval movement between plants is relatively low, ranging from 2-16% of larvae, and occurs mainly after reaching the second instar. Refuge plants in seed mixtures did not produce equivalent numbers of H. zea larvae, kernel injury, and larval development differed as compared with a pure stand of non-Bt plants. This suggests that there may be costs to larvae developing on refuge plants within seed mixtures and additional studies are warranted to define potential impacts.

  12. Heterozygosity of Knob-Associated Tandem Repeats and Knob Instability in Mitotic Chromosomes of Zea (Zea mays L. and Z. diploperennis Iltis Doebley)

    Institute of Scientific and Technical Information of China (English)

    Zhi-Yong XIONG; Yong LIU; Yong-Gang HE; Yun-Chun SONG; Ke-Xiu LI; Guan-Yuan HE

    2005-01-01

    Knobs are blocks of heterochromatin present on chromosomes of maize (Zea mays L.) and its relatives that have effects on the frequency of genetic recombination, as well as on chromosome behavior.Knob heterozygosity and instability in six maize inbred lines and one Z. diploperennis Iltis Doebley line were investigated using the fluorescence in situ hybridization (FISH) technique with knob-associated tandem repeats (180 bp and 350 bp (TR-1)) as probes. Signals of seven heterozygous knobs containing 180-bp repeats and of one heterozygous knob containing TR- 1 were captured in chromosomes of all materials tested according to the results of FISH, which demonstrates that the 180-bp repeat is the main contributor to knob heterozygosity compared with the TR-1 element. In addition, one target cell with two TR-1 signals on one homolog of chromosome 2L, which was different from the normal cells in the maize inbred line GB57,was observed, suggesting knob duplication and an instability phenomenon in the maize genome.

  13. Cross-resistance to alpha-cypermethrin after xanthotoxin ingestion in Helicoverpa zea (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Li, X; Zangerl, A R; Schuler, M A; Berenbaum, M R

    2000-02-01

    Cytochrome P450 monooxygenases (P450) are membrane-bound hemoproteins that play important roles in conferring protection against both naturally occurring phytochemicals and synthetic organic insecticides. Despite the potential for common modes of detoxification, cross-resistance between phytochemicals and synthetic organic insecticides has rarely been documented. In this study, we examined the responses of a susceptible strain of corn earworm, Helicoverpa zea (Boddie), a polyphagous noctuid, to exposure by an allelochemical infrequently encountered in its host plants and by an insecticide widely used for control purposes. Within a single generation, survivors of xanthotoxin exposure displayed higher levels of tolerance to alpha-cypermethrin than did unexposed control larvae. The F1 offspring of xanthotoxin-exposed survivors also displayed higher alpha-cypermethrin tolerance than did offspring of unexposed control larvae, suggesting that increased alpha-cypermethrin tolerance after xanthotoxin exposure represents, at least in part, heritable resistance. Administration of piperonyl butoxide, a P450 synergist, demonstrated that resistance to both xanthotoxin and alpha-cypermethrin is P450-mediated. Alpha-cypermethrin-exposed survivors, however, failed to show superior growth on xanthotoxin diets. Assays with control larvae, larvae induced by both xanthotoxin and alpha-cypermethrin, and survivors of LD50 doses of both compounds indicated that H. zea midgut P450s are capable of metabolizing both xanthotoxin and alpha-cypermethrin. Metabolism of each compound is significantly inhibited by the presence of the other compound, suggesting that at least one form of P450 in H. zea midguts degrades both compounds and may constitute the biochemical basis for possible cross-resistance. Compared with control larvae, xanthotoxin- and alpha-cypermethrin-induced larvae displayed 2- to 4-fold higher P450-mediated metabolism of both compounds. However, xanthotoxin- and alpha

  14. Endophytic Phoma sp. isolated from medicinal plants promote the growth of Zea mays

    Directory of Open Access Journals (Sweden)

    ASHWINI KEDAR

    2014-11-01

    Full Text Available Kedar A, Rathod D, Yadav A, Agarkar G, Rai M. 2014. Endophytic Phoma sp. isolated from medicinal plants promote the growth of Zea mays. Nusantara Bioscience 6: 132-139. Fungal endophytes are reported as rich sources of valuable secondary metabolites and could be used as bio-fertilizers. In the present study, we report growth promotion potential of two Phoma species isolated from Tinospora cordifolia and Calotropis procera on maize. The fungal endophytes enhanced growth in inoculated maize plants compared to non-inoculated plants. The main aim of this work was to assess the growth promotion activity of endophytic Phoma species on maize isolated from T. cordifolia and C. procera.

  15. Cytogenetics of monosomes in Zea mays. Progress report, October 1, 1975--January 31, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Weber, D. F.

    1976-10-01

    Monosomics lack a pairing partner in each meiotic cell and genes on an entire chromosome are present in the hemizygous condition. Monosomics for chromosomes 1, 2, 3, 4, 6, 7, 8, 9, and 10 in Zea mays were isolated utilizing a recently-discovered system. This is the first time that a series of this type has been recovered in any diploid organism. The monosomic plants are surprisingly vigorous, good cytological samples can be taken, and crosses made. We are isolating all possible monosomic types and characterizing them by studying the cytology of meiosis, the cytological behavior of monosomic chromosomes, the effect of monosomy and trisomy on intergenic and intragenic recombination, the frequency and types of spontaneous chromosomal aberrations arising in monosomics, the effect of monosomy on free amino acids, and the effect of monosomy on isozymes in leaves, the effect of trisomy on the lipid content, and the relative amounts of specific fatty acids in embryos.

  16. Collection of gravitropic effectors from mucilage of electrotropically-stimulated roots of Zea mays L

    Science.gov (United States)

    Fondren, W. M.; Moore, R.

    1987-01-01

    We placed agar blocks adjacent to tips of electrotropically stimulated primary roots of Zea mays. Blocks placed adjacent to the anode-side of the roots for 3 h induced significant curvature when subsequently placed asymmetrically on tips of vertically-oriented roots. Curvature was always toward the side of the root unto which the agar block was placed. Agar blocks not contacting roots and blocks placed adjacent to the cathode-side of electrotropically stimulated roots did not induce significant curvature when placed asymmetrically on tips of vertically-oriented roots. Atomic absorption spectrophotometry indicated that blocks adjacent to the anode-side of electrotropically-stimulated roots contained significantly more calcium than (1) blocks not contacting roots, and (2) blocks contacting the cathode-side of roots. These results demonstrate the presence of a gradient of endogenous Ca in mucilage of electrotropically-stimulated roots (i.e. roots undergoing gravitropic-like curvature).

  17. A gradient of endogenous calcium forms in mucilage of graviresponding roots of Zea mays

    Science.gov (United States)

    Moore, R.; Fondren, W. M.

    1988-01-01

    Agar blocks that contacted the upper sides of tips of horizontally-oriented roots of Zea mays contain significantly less calcium (Ca) than blocks that contacted the lower sides of such roots. This gravity-induced gradient of Ca forms prior to the onset of gravicurvature, and does not form across tips of vertically-oriented roots or roots of agravitropic mutants. These results indicate that (1) Ca can be collected from mucilage of graviresponding roots, (2) gravity induces a downward movement of endogenous Ca in mucilage overlying the root tip, (3) this gravity-induced gradient of Ca does not form across tips of agravitropic roots, and (4) formation of a Ca gradient is not a consequence of gravicurvature. These results are consistent with gravity-induced movement of Ca being a trigger for subsequent redistribution of growth effectors (e.g. auxin) that induce differential growth and gravicurvature.

  18. The involvement of glucose-6-phosphatase in mucilage secretion by root cap cells of Zea mays

    Science.gov (United States)

    Moore, R.; McClelen, C. E.

    1985-01-01

    In order to determine the involvement of glucose-6-phosphatase in mucilage secretion by root cap cells, we have cytochemically localized the enzyme in columella and peripheral cells of root caps of Zea mays. Glucose-6-phosphatase is associated with the plasmalemma and cell wall of columella cells. As columella cells differentiate into peripheral cells and begin to produce and secrete mucilage, glucose-6-phosphatase staining intensifies and becomes associated with the mucilage and, to a lesser extent, the cell wall. Cells being sloughed from the cap are characterized by glucose-6-phosphatase staining being associated with the vacuole and plasmalemma. These changes in enzyme localization during cellular differentiation in root caps suggest that glucose-6-phosphatase is involved in the production and/or secretion of mucilage by peripheral cells of Z. mays.

  19. Oxidative damage and cell-programmed death induced in Zea mays L. by allelochemical stress.

    Science.gov (United States)

    Ciniglia, Claudia; Mastrobuoni, Francesco; Scortichini, Marco; Petriccione, Milena

    2015-05-01

    The allelochemical stress on Zea mays was analyzed by using walnut husk washing waters (WHWW), a by-product of Juglans regia post-harvest process, which possesses strong allelopathic potential and phytotoxic effects. Oxidative damage and cell-programmed death were induced by WHWW in roots of maize seedlings. Treatment induced ROS burst, with excess of H2O2 content. Enzymatic activities of catalase were strongly increased during the first hours of exposure. The excess in malonildialdehyde following exposure to WHWW confirmed that oxidative stress severely damaged maize roots. Membrane alteration caused a decrease in NADPH oxidase activity along with DNA damage as confirmed by DNA laddering. The DNA instability was also assessed through sequence-related amplified polymorphism assay, thus suggesting the danger of walnut processing by-product and focusing the attention on the necessity of an efficient treatment of WHWW.

  20. QTL mapping of resistance to sheath blight in maize (Zea mays L.)

    Institute of Scientific and Technical Information of China (English)

    YANG Hua; YANG Junpin; RONG Tingzhao; TAN Jun; QIU Zhenggao

    2005-01-01

    The genetic linkage map has been constructed with 125 SSR markers based on BC1:2 population consisting of 322 lines derived from the combination of (CML270×478) ×CML270 in maize (Zea mays L.), covering 1939.0 cM of maize genome. The average mapping distance was about 15.5 cM. Three major QTLs of the relative resistant index of resistance to maize sheath blight (Rhizoctonia solani) had been located on chromosomes 1, 7 by composite interval mapping (CIM). 7 QTLs of the plant height have been located on chromosomes 3, 4, 5, 6. Five QTLs of ear height have been located on chromosomes 3, 4, 6. The resistance to the sheath blight is shown to be not relative to plant height and ear height genetically. Inbred line CML270 was used for molecular assisted selection and cloning the genes.

  1. Root graviresponsiveness and columella cell structure in carotenoid-deficient seedlings of Zea mays

    Science.gov (United States)

    Moore, R.; McClelen, C. E.

    1985-01-01

    Root graviresponsiveness in normal and carotenoid-deficient mutant seedlings of Zea mays was not significantly different. Columella cells in roots of mutant seedlings were characterized by fewer, smaller, and a reduced relative volume of plastids as compared to columella cells of normal seedlings. Plastids in columella cells of mutant seedlings possessed reduced amounts of starch. Although approximately 10 per cent of the columella cells in mutant seedlings lacked starch, their plastids were located at the bottom of the cell. These results suggest that (i) carotenoids are not necessary for root gravitropism, (ii) graviresponsiveness is not necessarily proportional to the size, number, or relative volume of plastids in columella cells, and (iii) sedimentation of plastids in columella cells may not result directly from their increased density due to starch content. Plastids in columella cells of normal and mutant seedlings were associated with bands of microtubule-like structures, suggesting that these structures may be involved in 'positioning' plastids in the cell.

  2. The effect of ethylene on root growth of Zea mays seedlings

    Science.gov (United States)

    Whalen, M. C.; Feldman, L. J.

    1988-01-01

    The control of primary root growth in Zea mays cv. Merit by ethylene was examined. At applied concentrations of ethylene equal to or greater than 0.1 microliter L-1, root elongation during 24 h was inhibited. The half-maximal response occurred at 0.6 microliter L-1 and the response saturated at 6 microliters L-1. Inhibition of elongation took place within 20 min. However, after ethylene was removed, elongation recovered to control values within 15 min. Root elongation was also inhibited by green light. The inhibition caused by a 24-h exposure to ethylene was restricted to the elongating region just behind the apex, with inhibition of cortical cell elongation being the primary contributor to the effect. Based on use of 2,5-norbornadiene, a gaseous competitive inhibitor of ethylene, it was concluded that endogenous ethylene normally inhibits root elongation.

  3. The influence of gravity on the formation of amyloplasts in columella cells of Zea mays L

    Science.gov (United States)

    Moore, R.; Fondren, W. M.; Koon, E. C.; Wang, C. L.

    1986-01-01

    Columella (i.e., putative graviperceptive) cells of Zea mays seedlings grown in the microgravity of outer space allocate significantly less volume to putative statoliths (amyloplasts) than do columella cells of Earth-grown seedlings. Amyloplasts of flight-grown seedlings are significantly smaller than those of ground controls, as is the average volume of individual starch grains. Similarly, the relative volume of starch in amyloplasts in columella cells of flight-grown seedlings is significantly less than that of Earth-grown seedlings. Microgravity does not significantly alter the volume of columella cells, the average number of amyloplasts per columella cell, or the number of starch grains per amyloplast. These results are discussed relative to the influence of gravity on cellular and organellar structure.

  4. Efficient isolation, purification, and characterization of the Helicoverpa zea VHDL receptor.

    Science.gov (United States)

    Persaud, Deryck R; Yousefi, Vandad; Haunerland, Norbert

    2003-12-01

    The study of fat body receptors (e.g., VHDL receptor) in Lepidoptera has been irksome due to the fact that isolation and purification of these proteins are difficult and resulted in extremely low yields. A rapid and efficient method is presented for the purification of Helicoverpa zea VHDL receptor by the use of VHDL-biotin ligand complexed to streptavidin coated magnetic beads. The technique can be easily applied to other ligands and allows for the purification of membrane proteins with higher yields compared to previously used methods involving immunopurification. Although the purified protein can be characterized by Western and non-radioactive ligand blots using enhanced chemiluminescence (ECL), a non-radioactive ligand blot method using VHDL-FITC is presented, which allows for the quick analysis of the receptor directly from the blot under standard UV light. Sufficient receptor protein has been derived for amino acid analysis, receptor-ligand and xenobiotic binding studies.

  5. Accumulation potentials of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) in maize (Zea mays).

    Science.gov (United States)

    Krippner, Johanna; Falk, Sandy; Brunn, Hubertus; Georgii, Sebastian; Schubert, Sven; Stahl, Thorsten

    2015-04-15

    Uptake of perfluoroalkyl acids (PFAAs) by maize represents a potential source of exposure for humans, either directly or indirectly via feed for animals raised for human consumption. The aim of the following study was, therefore, to determine the accumulation potential of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) in maize (Zea mays). Two different concentrations of PFAAs were applied as aqueous solution to the soil to attain target concentrations of 0.25 mg or 1.00 mg of PFAA per kg of soil. Maize was grown in pots, and after harvesting, PFAA concentrations were measured in the straw and kernels of maize. PFCA and PFSA concentrations of straw decreased significantly with increasing chain length. In maize kernels, only PFCAs with a chain length ≤ C8 as well as perfluorobutanesulfonic acid (PFBS) were detected. The highest soil-to-plant transfer for both straw and kernels was determined for short-chained PFCAs and PFSAs.

  6. Antimony uptake by Zea mays (L.) and Helianthus annuus (L.) from nutrient solution.

    Science.gov (United States)

    Tschan, Martin; Robinson, Brett; Schulin, Rainer

    2008-04-01

    We investigated the extent of Sb uptake by maize (Zea mays) and sunflower (Helianthus annuus) from nutrient solutions containing concentrations from 3 to 24 mg/L of potassium antimonate, with the aim of determining the potential of Sb to enter the food chain. The maximum shoot Sb concentrations in Z. mays and H. annuus were 41 mg/kg and 77 mg/kg dry weight, respectively. There was no significant difference in Sb uptake between species. The average bioaccumulation coefficients (the plant/solution concentration quotients) were 1.02 and 1.93 for Z. mays and H. annuus, respectively. Phosphate addition did not affect plant growth or Sb uptake. Antimony uptake by both Z. mays and H. annuus is unlikely to pose a health risk to animals and humans.

  7. Sequence diversity and virulence in Zea mays of Maize streak virus isolates.

    Science.gov (United States)

    Martin, D P; Willment, J A; Billharz, R; Velders, R; Odhiambo, B; Njuguna, J; James, D; Rybicki, E P

    2001-09-30

    Full genomic sequences were determined for 12 Maize streak virus (MSV) isolates obtained from Zea mays and wild grass species. These and 10 other publicly available full-length sequences were used to classify a total of 66 additional MSV isolates that had been characterized by PCR-restriction fragment length polymorphism and/or partial nucleotide sequence analysis. A description is given of the host and geographical distribution of the MSV strain and subtype groupings identified. The relationship between the genotypes of 21 fully sequenced virus isolates and their virulence in differentially MSV-resistant Z. mays genotypes was examined. Within the only MSV strain grouping that produced severe symptoms in maize, highly virulent and widely distributed genotypes were identified that are likely to pose the most serious threat to maize production in Africa. Evidence is presented that certain of the isolates investigated may be the products of either intra- or interspecific recombination.

  8. Sobre la muerte voluntaria

    Directory of Open Access Journals (Sweden)

    Juan Álvarez-Cienfuegos Fidalgo

    2012-03-01

    Full Text Available El problema de cómo morir en nuestra sociedad se ha convertido en una inquietud para los ciudadanos y la reflexión moral. Especialmcnte por dos razones: por el desarrollo de la tecnología médica y por el hecho de que la mayor parte de los fallecimientos tienen lugar fuera del hogar, donde tradicionalmente ocurra el deceso. El presente artículo tiene como objetivo acercarse a esta cuestión. Para ello, se parte de la autonomía del ciudadano, con derecho a decidir sobre lo que considera cuál sea su manera de vivir y de morir. A tal fin, se hace una breve introducción sobre el dolor, el suicidio y la muerte, desde un punto de vista antropológico, pasando, después, a mostrar las cuestiones relacionadas con el problema de la eutanasia, donde la atención se dirigirá, ante todo, al enjuiciamiento crítico del tenso equilibrio en el que se mantienen dos principios fundamentales de la bioética: el de no maleficencia y el de autonomía del ciudadano.The problem of how to die in modern society has become a concern for both the citizen and moral reflection for two reasons in particular: due to developments in medical technology, and because most deaths occur outside the honre, where they traditionaÍlY took place. This paper addresses this issue, starting from citizen autonomy, the right to decide on what s/he considers to be his or her way of living and dying. To this end, a brief introduction considers pain, suicide and death from an anthropological viewpoint. Questions related to the problem of euthanasia are then exposed, with particular attention to, above all the critical judgement of the tense balance in which two fundamental principies of bioethics are held, the principle of non-maleficence and that of citizen autonomy.

  9. Uptake and accumulation of copper by roots and shoots of maize(Zea may L.)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effects of different concentrations of copper sulfate on rootand shoot growth of maize(Zea mays L.) and the uptake and accumulation of Cu2+ by its roots and shoots were investigated in the present study. The concentrations of opper sulfate (CuSO4.5H2O) used were in the range of 10-5-10-3mol/L. Root growth decreased progressively with increasing concentration of Cu2+ in solution. The seedlings exposed to 10-3 mol/L Cu exhibited substantial growth reduction, yielding only 68% of the root length of the control. The shoot growth of the seedlings grown at 10-5-10-4 mol/L Cu2+ were more or less than the same as the control seedlings. The leaves treated with 10-3 mol/L Cu2+ were obviously inhibited in shoot growth. The fresh and dry weights both in roots and shots decreased progressively with increasing Cu2+ concentration.This fits well with the above mentioned effects of copper sulfate on root growth. Zea mays has considerable ability to remove Cu from solutions and accumulate it. The Cu content in roots of Z. Mays increased with increasing solution concentration of Cu2+. The amount of Cu in roots of plants treated with 10-3, 10-4 and 10-5 mol/L Cu2+ were 10, 8 and 1.5 fold, respectively, greater than that of roots of control plant. However, the plants transported and concentrated only a small amount of Cu in their shoots.

  10. Francisco Antonio Zea: periodista, botánico y político

    Directory of Open Access Journals (Sweden)

    Soto Arango, Diana E.

    1996-06-01

    Full Text Available This work analyzes the journalistic facet of Francisco Antonio Zea, whose first article, «Avisos de Hebephilo», was published in 1791 in the Papel Periódico de la ciudad de Santa Fé de Bogotá. His interest for the press shows at his stage of student in the National Institute of France, but won't be up to 1803, at his return to Madrid, when he proves his talent for the organization and journalistic administration on The Mercury and on the Gazette de Madrid. Later on, being manager of the Royal Botanical Garden of Madrid, he shares the management of the Semanario de Agricultura y Artes, and, finally, in 1818 establishes and directs the Venezuelan Correo del Orinoco.

    Este trabajo analiza la faceta periodística de Francisco Antonio Zea, cuyo primer artículo, «Avisos de Hebephilo», se publicó en 1791 en el Papel Periódico de la ciudad de Santa Fé de Bogota. Su interés por la prensa se manifiesta en su etapa de estudiante en el Instituto Nacional de Francia, pero no será hasta 1803, a su regreso a Madrid, cuando evidencie sus dotes para la organización y dirección periodísticas en El Mercurio y en la Gaceta de Madrid. Posteriormente, siendo director del Real Jardín Botánico de Madrid, comparte la dirección del Semanario de Agricultura y Artes, y, finalmente, en 1818 funda y dirige el venezolano Correo del Orinoco.

  11. INFLUENCE OF CROP SEQUENCES ON AGRONOMIC CHARACTERISTICS OF CORN (Zea mays L. UNDER NO-TILLAGE INFLUÊNCIA DE SUCESSÃO DE CULTURAS SOBRE CARACTERÍSTICAS AGRONÔMICAS DO MILHO (Zea mays L. EM PLANTIO DIRETO

    Directory of Open Access Journals (Sweden)

    Liovando Marciano da Costa

    2007-09-01

    Full Text Available

    Evoluated agronomic characteristics of corn in six crop sequences (corn-corn, soybean-corn, sunflower-corn, pearl milletcorn, sorghum-corn and pigeon pea-corn under no-tillage for three years, in Rio Verde, Goiás State. Significance was observed by the test F for plant height, 100 grain weight and grain moisture. Pigeon pea, soybean, sunflower and pearl millet, resulted in taller corn plants. No statistical differences were found between crop sequences for corn grain yield and other characteristics.

    KEY-WORDS: Crop sequences; corn; agronomic characteristics.

    Avaliaram-se características agronômicas na cultura do milho em seis sucessões de culturas (milho-milho, soja-milho,girassol-milho, milheto-milho, sorgo-milho e guandu milho em plantio direto, durante três anos, em Rio Verde, Goiás. Observou-se significância, pelo teste F, para altura de planta, peso de 100 grãos e umidade dos grãos na colheita. Guandu, soja, girassol e milheto proporcionaram maior altura da planta de milho. Não foram observadas diferenças estatísticas entre as sucessões para produtividades de grãos e demais características avaliadas.

    PALAVRAS-CHAVE: Sucessão de culturas; milho; características agronômicas.

  12. Debate sobre el parto (normal).

    OpenAIRE

    Vidal Puèrtolas, Adela

    2008-01-01

    El artículo pretende una reflexión sobre la asistencia al parto, desde el punto de vista de una comadrona. A raíz de la apuesta oficial sobre el cómo para humanizar la asistencia obstétrica hospitalaria, se plantea un análisis de las implicaciones profesionales y los matices culturales que influyen sobre la vivencia de la experiencia del parto. La importancia de la psico-profilaxis en la preparación al parto como vehículo terapéutico de acercamiento a la realidad y de ...

  13. Debate internacional sobre pobreza

    Directory of Open Access Journals (Sweden)

    Neritza Alvarado Chacín

    2016-01-01

    Full Text Available El objetivo del artículo es organizar la proliferación de ideas en torno de la pobreza, a menudo dispersas, difusas y confusas en la literatura, bosquejando sistematizadamente un marco teórico referencial útil al abordaje científico de este fenómeno, en investigaciones teóricas y aplicadas, así como en la enseñanza y discusión de tales temas en el ámbito universitario. Para ello, se compendian, organizan y clasifican diversos enfoques sobre la pobreza, según los criterios presentes en los planteamientos de autores e instituciones relevantes que han contribuido a la reflexión desde distintas lecturas, teniendo en cuenta que no existe consenso en torno a una definición. La investigación es exploratoria-documental. Se aplican las técnicas del arqueo electrónico y físico de la información, el fichaje computarizado y la reducción de la misma en tablas de contenido. Se precisa el alcance de las mismas en el tiempo, según la evolución conceptual que han experimentado en el debate internacional. Se señalan algunas ventajas y desventajas de los principales enfoques, que han sido reconocidas en el mismo debate.

  14. Leopoldo Zea e o movimento latino-americano de História das idéias Leopoldo Zea and the Latin-American movement of History of Ideas

    Directory of Open Access Journals (Sweden)

    Eugênio Rezende de Carvalho

    2010-06-01

    Full Text Available O artigo analisa as etapas de fundação e consolidação de um dos mais importantes movimentos intelectuais da América Latina no século XX - o movimento latino-americano de História das Ideias -, a partir, sobretudo, das ações e escritos de seu principal líder e fundador, o filósofo mexicano Leopoldo Zea Aguilar (1912-2004. Na etapa de fundação, que corresponde à década de 1940, o foco principal é na obra inicial de Zea, bem como em seus primeiros esforços no sentido da articulação e organização institucional do movimento em escala continental. Já na etapa seguinte, que corresponde à década de 1950, é abordado o processo de consolidação orgânica e epistemológica do movimento.This article analyzes the stages of foundation and consolidation of one of the most important intellectual movements of Latin America in the twentieth century - the Latin-American movement of History of Ideas -, starting from actions and writings of its main leader and founder, the Mexican philosopher Leopoldo Zea Aguilar (1912-2004. In the 1940s, during the foundation period, the main focus is on the primary work of Zea, as well as on his first efforts to articulate and organize this movement in continental scale. Moreover, in the following stage held in the 1950s, the process of organic and epistemology consolidation of the movement is invoked.

  15. Influência da idade dos ovos de Helicoverpa zea (Boddie no parasitismo de Trichogramma pretiosum Riley Influence of egg age of Helicoverpa zea (Boddie on the parasitism by Trichogramma pretiosum Riley

    Directory of Open Access Journals (Sweden)

    Dirceu Pratissoli

    1999-05-01

    Full Text Available Entre os agentes de controle biológico, os parasitóides do gênero Trichogramma representam um dos mais importantes grupos, pois controlam diversas pragas na agricultura. Este trabalho teve por objetivo determinar a melhor idade dos ovos de Helicoverpa zea (Boddie para que Trichogramma pretiosum Riley tenha uma melhor eficiência no controle dessa praga. Ovos com um, dois, três e quatro dias foram oferecidos para o parasitismo, por um período de 24 horas a 25 ± 1ºC, umidade relativa de 70 ± 10% e fotofase de 14 horas. Ovos de um dia de idade apresentaram a maior taxa de parasitismo, viabilidade e número de descendentes por fêmea. A mais alta eficiência de T. pretiosum será alçancada no campo, quando for observado maior densidade de ovos de H. zea com, no máximo, dois dias de desenvolvimento embrionário.Among the agents of biological control, the parasitoids of the genus Trichogramma represent one of the most important groups, as they are able to control many pests in agriculture. The objective of this work was to determine the best age of the Helicoverpa zea (Boddie eggs so that the Trichogramma pretiosum Riley could have the best efficiency against this pest. One, two, three and four-days-old eggs were offered for the parasitism during 24 hours, at 25 ± 1ºC, relative humidity 70 ± 10% and photofase of 14 hours. One-day-old eggs showed the highest rates of parasitism, viability, and number of descendants for each female. The highest efficiency with T. pretiosum will be reached in the field conditions, when observed a great density of H. zea eggs until two days of embryonic development.

  16. Activity and multiple forms of peroxidase in Zea mays and Medicago sativa treated and non-treated with lead

    Energy Technology Data Exchange (ETDEWEB)

    Maier, R.

    1978-02-11

    The influence of lead on peroxidase was studied in young plants of Zee mays and Medicago sativa grown in solutions of Pb(NO/sub 3/)/sub 2/. The content of nitrate in the control- and the lead-solutions was equalized by NaNO/sub 3/. In the patterns of the multiple forms in roots and leaves of Zea and Medicago qualitatively no, or respectively negligible, change between control and lead-treated plants takes place. The temperature during the lead-treatment does not effect the numbers and the positions of bands. The bands' activity of peroxidase in lead-treated plants differs clearly from untreated plants, resulting in a different activity of the whole enzyme. In the roots and in the leaves of Zea as well as in the leaves of Medicago the relative activity of the peroxidase in lead-treated plants is raised. In the roots of Medicago the relative activity decreased slightly.

  17. Unraveling the role of dark septate endophyte (DSE) colonizing maize (Zea mays) under cadmium stress: physiological, cytological and genic aspects

    OpenAIRE

    Jun-ling Wang; Tao Li; Gao-yuan Liu; Joshua M. Smith; Zhi-wei Zhao

    2016-01-01

    A growing body of evidence suggests that plant root-associated fungi such as dark septate endophytes (DSE) can help plants overcome many biotic and abiotic stresses, of great interest is DSE-plant metal tolerance and alleviation capabilities on contaminated soils. However, the tolerance and alleviation mechanisms involved have not yet been elucidated. In the current study, the regulation and physiological response of Zea mays to its root-associated DSE, Exophiala pisciphila was analyzed under...

  18. Pengelolaan Hara Kalium Berdasarkan Batas Kritis Untuk Tanaman Jagung (Zea mays L.) Pada Berbagai Status Hara di Tanah Inceptisol

    OpenAIRE

    Putra, Irwan Agusnu

    2011-01-01

    IRWAN AGUSNU PUTRA, 2010. Potassium Based Nutrient Management of Critical Level For Maize (Zea mays L.) at Various Nutrient Status in the Inceptisol Soil. Under his guidance, Dr. Ir. Hamidah Hanum, MP as Chairman of the Commission of Advisors with members Dr. Ir. Chairani Hanum, MP. In North Sumatra, most of the planting area of corn in the ground Inceptisol widespread, also dominated by the relatively high clay content so that the fixation of potassium are very strong which resulted in the c...

  19. Influence of Dual-Bt Protein Corn on Bollworm, Helicoverpa zea (Boddie), Survivorship on Bollgard II Cotton.

    Science.gov (United States)

    Von Kanel, M B; Gore, J; Catchot, A; Cook, D; Musser, F; Caprio, M

    2016-04-01

    Similar Cry proteins are expressed in both Bt corn, Zea mays L., and cotton, Gossypium hirsutum (L.), commercial production systems. At least one generation of corn earworm, Helicoverpa zea (Boddie), completes development on field corn in the Mid-South before dispersing across the landscape into other crop hosts like cotton. A concern is that Bt corn hybrids may result in selection for H. zea populations with a higher probability of causing damage to Bt cotton. The objective of this study was to determine the susceptibility of H. zea offspring from moths that developed on non-Bt and VT Triple Pro (VT3 PRO) field corn to lyophilized Bollgard II cotton tissue expressing Cry1Ac and Cry2Ab. Offspring of individuals reared on VT3 PRO expressing Cry1A.105 and Cry2Ab had a significantly higher LC50 two out of the three years this study was conducted. Excess larvae were placed on artificial diet and allowed to pupate to determine if there were any inheritable fitness costs associated with parental development on VT3 PRO corn. Offspring resulting from males collected from VT3 PRO had significantly lower pupal weight and longer pupal duration compared with offspring of individuals collected from non-Bt corn. However, offspring from females collected from VT3 PRO were not different from non-Bt offspring. Paternal influence on offspring in insects is not commonly observed, but illustrates the side effects of development on a transgenic plant expressing less than a high dose, 25 times the concentration needed to kill susceptible larvae.

  20. Cannibalism of Helicoverpa zea (Lepidoptera: Noctuidae) from Bacillus thuringiensis (Bt) transgenic corn versus non-Bt corn.

    Science.gov (United States)

    Chilcutt, Charles F

    2006-06-01

    Because of the importance of cannibalism in population regulation of Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) in corn, Zea mays L., it is useful to understand the interactions between Bacillus thuringiensis (Bt) transgenic corn and cannibalism. To determine the effects of Bt corn on cannibalism in H. zea, pairs of the same or different instars were taken from Bt or non-Bt corn and placed on artificial diet in proximity. Cannibalism occurred in 91% of pairs and was approximately 7% greater for pairs of larvae reared from Bt transgenic corn (95%) than from non-Bt corn (88%). Also, first instar by first instar pairs had a lower rate of cannibalism than other pairs. Time until cannibalism was not different for larvae from Bt corn versus non-Bt corn. Pupation rate of cannibals and surviving victims was not different for pairs from Bt corn versus non-Bt corn. Finally, cannibalism increased pupation rate of cannibals from both Bt and non-Bt corn by approximately 23 and 12%, respectively, although the increases were not significant. Thus, negative effects of Bt on larvae were compensated by increased cannibalism in comparison with larvae reared on non-Bt corn, which increased larval survival to levels comparable with larvae reared on non-Bt plants.

  1. Phytotoxicity assay of diesel fuel-spiked substrates remediated with Pleurotus tuberregium using Zea mays

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    E M Ogbo

    2010-06-01

    Full Text Available Summary: The remediation of soil contaminated with petroleum based compounds by white rot fungi is well documented.  In this study the ability of diesel fuel contaminated soils treated with the fungus Pleurotus tuber-regium to support plant growth was tested.  Pleurotus tuber-regium was grown in different levels (2.50, 5.00, 10.00% and control- no fungus for each level of contamination of diesel fuel contaminated soil and sawdust. The removal of petroleum hydrocarbons was highest in the 5.00% level of contamination where 55.53% of the petroleum hydrocarbons were removed. The least reduction in hydrocarbons was in the 10.00% level of contamination where only 35.53% of the hydrocarbons were removed. After the remediation the toxicity of the soils were tested by growing Zea mays in the treated soils. There was reduction in the toxicity of the soils treated with Pleurotus tuber-regium. Germination of the seeds of the test plant in treated 2.50 and 5.00% diesel fuel contaminated substrates was higher than that in the control. Germination of seeds in the 10.00% diesel fuel contaminated substrates was less than that in the control. The continued growth of the plant in the treated soils however showed no significant difference between them and the control using leaf area, plant height, fresh weight, dry weight and root length indices. The formation of lateral roots was however adversely affected in the treated 10.00% contaminated soil only substrate. The fungus was able to reduce the toxicity of diesel fuel contaminated substrates when compared with control in which there was no remediation. Industrial relevance: Nigeria is an oil producing country with heavy or high reliance on diesel fuel for use in cars and electric power generating sets. The transportation of diesel fuel is by tankers and pipelines. There have been cases of spills which has adverse effect on the environment. The study aims to solve the process of amelioration of the environment

  2. Efectos en suelo y plantas debido al riego de un cultivo de maíz (Zea mays L. con el efluente de la planta de tratamiento de aguas residuales de la ciudad de Jinotepe

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    E. Umaña

    2006-08-01

    Full Text Available Un estudio de reúso de aguas para el riego de una parcela de cultivo de maíz (Zea mays L. se realizó en la comunidad de El Aguacate municipio de Jinotepe aprovechando los efluentes de la planta de tratamiento de aguas residuales de la ciudad de Jinotepe, con el objetivo de evaluar los efectos de esta práctica sobre las características físicas y químicas del suelo y los rendimientos obtenidos con respecto a una parcela de referencia. El manejo que se dio al cultivo fue el que tradicionalmente realizan los agricultores de la zona excepto que no se aplicó ningún fertilizante para aprovechar los nutrientes contenidos en el agua residual tratada. El monitoreo de las características del suelo se realizaron en una etapa inicial, una etapa intermedia y una etapa final del ciclo del cultivo. Los resultados obtenidos indican que estadísticamente las variaciones experimentadas en las características del suelo en la parcela de estudio no fueron significativas. Por otro lado, la calidad del efluente en cuanto al contenido de nutrientes, compensa el no uso de fertilizantes por cuanto los rendimientos obtenidos en el estudio superaron hasta en un 60 % la media de rendimientos de maíz en la zona reportados que es de 1.61 t/ha.

  3. Physiological Responses of Zea mays Seedlings to Interactions Between Cadmium and Salinity

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effects of 0, 2.5, 5.0, and 10.0 μmol/L Cd2+ (Cd(NO3)2·4H2O) and 0, 10, 25, 50, and 100 mmol/L NaCl on growth,photosynthesis and the content of some ions in maize (Zea mays L.) were investigated in the present study. With increasing concentrations of Cd2+ or NaCl alone in Hoagland nutrient solution, the chlorophylls and starch content decreased. Combination treatment with salinity and cadmium increased the negative effects observed following the two stresses alone. Plants exhibiting growth retardation in response to one mild stress factor (25-50 mmol/L NaCl) became more tolerant to the other stress factor (Cd). The exposure of plants to cadmium caused a partial reversal of the effects of salinity. Root and shoot growth, ion accumulation and levels of photosynthetic pigments were improved at moderate concentrations of the two stress factors imposed jointly.

  4. A seed mixture increases dominance of resistance to Bt cotton in Helicoverpa zea.

    Science.gov (United States)

    Brévault, Thierry; Tabashnik, Bruce E; Carrière, Yves

    2015-05-07

    Widely grown transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) can benefit agriculture, but adaptation by pests threatens their continued success. Refuges of host plants that do not make Bt toxins can promote survival of susceptible insects and delay evolution of resistance, particularly if resistance is inherited as a recessive trait. However, data have been lacking to compare the dominance of resistance when Bt and non-Bt seeds are planted in random mixtures versus separate blocks. Here we report results from greenhouse experiments with transgenic cotton producing Bt toxin Cry1Ac and the bollworm, Helicoverpa zea, showing that the dominance of resistance was significantly higher in a seed mixture relative to a block of Bt cotton. The proportion of larvae on non-Bt cotton plants in the seed mixture was also significantly higher than expected under the null hypothesis of random distribution. In simulations based on observed survival, resistance evolved 2- to 4.5-fold faster in the seed mixture relative to separate blocks of Bt and non-Bt cotton. These findings support previous modelling results indicating that block refuges may be more effective than seed mixtures for delaying resistance in pests with mobile larvae and inherently low susceptibility to the toxins in Bt crops.

  5. Non-destructive leaf area measurement in maize (Zea mays L.).

    Science.gov (United States)

    Sezer, Ismail; Oner, Fatih; Mut, Zeki

    2009-09-01

    In this research, leaf area prediction model was developed for some leaf-used maize (Zea mays L.) cultivars namely Coluna, Luce, Maveric, Ranchero, TTM-813, Zamora and RX-788 grown in Black Sea region of Turkey. Lamina width, length and leaf area were measured without destroying the leaf to develop the models. The actual leaf areas of the plants were measured by PLACOM Digital Planimeter and multiple regression analysis with Excel 2003 computer package program was performed for the plants separately. The produced leaf area prediction models in the present study were formulized as LA = a - (b x W2) + [c x (W x L)] where LA is leaf area, W is leaf width, L is leaf length and a, b, c are coefficiencies. R2 values for maize cultivars tested varied with species from 0.95 in Luce to 0.98 in Maveric. All R2 values and standard errors were found to be significant at the p < 0.001 level.

  6. Growth promoting characteristics of rhizobacteria and AM Fungi for biomass amelioration of Zea mays

    Directory of Open Access Journals (Sweden)

    Kumar Manoj

    2015-01-01

    Full Text Available Plant growth promoting rhizobacteria (PGPR and mycorrhiza were evaluated on the growth (biomass and yield of Zea mays. In the present study, selective rhizospheric PGPR (Azotobacter chroococcum, Pseudomonas aeruginosa, Azospirillum brasilense and Streptomyces sp. and a combination of six strains of arbuscular mycorrhizal fungi (AMF (Acaulospora morrowae, Gigaspora margarita, Glomus constrictum, Glomus mossae, Glomus aggregatum and Scutellospora calospora were isolated and identified with standard methods and 16S rRNA sequence analysis. PGPR and AMF were checked for their growth-promoting behavior under specific treatment conditions. The 30-48-day-old treated plants in all combinations showed a significantly higher mass value. The average dry weight from the shoot was in a range from 41-52% as compared to the control. This increase also translated into a higher mass value of the roots. Overall, an 82% growth rate was observed in terms of height as the consequence of biomass production, specifically in the case of AMF + rhizobacteria combination. We report an efficient, sustainable and cost-effective biofertilizer for enhanced biomass of Z. mays, one of the staple food crops worldwide.

  7. Overexpression of Arabidopsis molybdenum cofactor sulfurase gene confers drought tolerance in maize (Zea mays L.).

    Science.gov (United States)

    Lu, Yao; Li, Yajun; Zhang, Jiachang; Xiao, Yitao; Yue, Yuesen; Duan, Liusheng; Zhang, Mingcai; Li, Zhaohu

    2013-01-01

    Abscisic acid (ABA) is a key component of the signaling system that integrates plant adaptive responses to abiotic stress. Overexpression of Arabidopsis molybdenum cofactor sulfurase gene (LOS5) in maize markedly enhanced the expression of ZmAO and aldehyde oxidase (AO) activity, leading to ABA accumulation and increased drought tolerance. Transgenic maize (Zea mays L.) exhibited the expected reductions in stomatal aperture, which led to decreased water loss and maintenance of higher relative water content (RWC) and leaf water potential. Also, transgenic maize subjected to drought treatment exhibited lower leaf wilting, electrolyte leakage, malondialdehyde (MDA) and H(2)O(2) content, and higher activities of antioxidative enzymes and proline content compared to wild-type (WT) maize. Moreover, overexpression of LOS5 enhanced the expression of stress-regulated genes such as Rad 17, NCED1, CAT1, and ZmP5CS1 under drought stress conditions, and increased root system development and biomass yield after re-watering. The increased drought tolerance in transgenic plants was associated with ABA accumulation via activated AO and expression of stress-related gene via ABA induction, which sequentially induced a set of favorable stress-related physiological and biochemical responses.

  8. Identification and characterization of the RCI2 gene family in maize (Zea mays).

    Science.gov (United States)

    Zhao, Yang; Tong, Haiqing; Cai, Ronghao; Peng, Xiaojian; Li, Xiaoyu; Gan, Defang; Zhu, Suwen

    2014-12-01

    Rare-cold-inducible (RCI2) genes are structurally conserved members that encode small, highly hydrophobic proteins involved in response to various abiotic stresses. Phylogenetic and functional analyses of these genes have been conducted in Arabidopsis, but an extensive investigation of the RCI2 gene family has not yet been carried out in maize. In the present study, 10 RCI2 genes were identified in a fully sequenced maize genome. Structural characterization and expression pattern analysis of 10 ZmRCI2s (Zea mays RCI2 genes) were subsequently determined. Sequence and phylogenetic analyses indicated that ZmRCI2s are highly conserved, and most of them could be grouped with their orthologues from other organisms. Chromosomal location analysis indicated that ZmRCI2s were distributed unevenly on seven chromosomes with two segmental duplication events, suggesting that maize RCI2 gene family is an evolutionarily conserved family. Putative stress-responsive cis-elements were detected in the 2-kb promoter regions of the 10 ZmRCI2s. In addition, the 10 ZmRCI2s showed different expression patterns in maize development based on transcriptome analysis. Further, microarray and quantitative real-time PCR (qRT-PCR) analysis showed that each maize RCI2 genes were responsive to drought stress, suggesting their important roles in drought stress response. The results of this work provide a basis for future cloning and application studies of maize RCI2 genes.

  9. Accumulation of Hydrocarbons by Maize (Zea mays L.) in Remediation of Soils Contaminated with Crude Oil.

    Science.gov (United States)

    Liao, Changjun; Xu, Wending; Lu, Guining; Liang, Xujun; Guo, Chuling; Yang, Chen; Dang, Zhi

    2015-01-01

    This study has investigated the use of screened maize for remediation of soil contaminated with crude oil. Pots experiment was carried out for 60 days by transplanting maize seedlings into spiked soils. The results showed that certain amount of crude oil in soil (≤2 147 mg·kg(-1)) could enhance the production of shoot biomass of maize. Higher concentration (6 373 mg·kg(-1)) did not significantly inhibit the growth of plant maize (including shoot and root). Analysis of plant shoot by GC-MS showed that low molecular weight polycyclic aromatic hydrocarbons (PAHs) were detected in maize tissues, but PAHs concentration in the plant did not increase with higher concentration of crude oil in soil. The reduction of total petroleum hydrocarbon in planted soil was up to 52.21-72.84%, while that of the corresponding controls was only 25.85-34.22% in two months. In addition, data from physiological and biochemical indexes demonstrated a favorable adaptability of maize to crude oil pollution stress. This study suggested that the use of maize (Zea mays L.) was a good choice for remediation of soil contaminated with petroleum within a certain range of concentrations.

  10. Differential expression of superoxide dismutase genes in aphid-stressed maize (Zea mays L. seedlings.

    Directory of Open Access Journals (Sweden)

    Hubert Sytykiewicz

    Full Text Available The aim of this study was to compare the expression patterns of superoxide dismutase genes (sod2, sod3.4, sod9 and sodB in seedling leaves of the Zea mays L. Tasty Sweet (susceptible and Ambrozja (relatively resistant cultivars infested with one of two hemipteran species, namely monophagous Sitobion avenae F. (grain aphid or oligophagous Rhopalosiphum padi L. (bird cherry-oat aphid. Secondarily, aphid-elicited alternations in the antioxidative capacity towards DPPH (1,1-diphenyl-2-picrylhydrazyl radical in insect-stressed plants were evaluated. Comprehensive comparison of expression profiles of the four sod genes showed that both insect species evoked significant upregulation of three genes sod2, sod3.4 and sod9. However, aphid infestation affected non-significant fluctuations in expression of sodB gene in seedlings of both maize genotypes. The highest levels of transcript accumulation occurred at 8 h (sod2 and sod3.4 or 24 h (sod9 post-infestation, and aphid-induced changes in the expression of sod genes were more dramatic in the Ambrozja cultivar than in the Tasty Sweet variety. Furthermore, bird cherry-oat aphid colonization had a more substantial impact on levels of DPPH radical scavenging activity in infested host seedlings than grain aphid colonization. Additionally, Ambrozja plants infested by either hemipteran species showed markedly lower antioxidative capacity compared with attacked Tasty Sweet plants.

  11. Targeted mutagenesis in Zea mays using TALENs and the CRISPR/Cas system.

    Science.gov (United States)

    Liang, Zhen; Zhang, Kang; Chen, Kunling; Gao, Caixia

    2014-02-20

    Transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems have emerged as powerful tools for genome editing in a variety of species. Here, we report, for the first time, targeted mutagenesis in Zea mays using TALENs and the CRISPR/Cas system. We designed five TALENs targeting 4 genes, namely ZmPDS, ZmIPK1A, ZmIPK, ZmMRP4, and obtained targeting efficiencies of up to 23.1% in protoplasts, and about 13.3% to 39.1% of the transgenic plants were somatic mutations. Also, we constructed two gRNAs targeting the ZmIPK gene in maize protoplasts, at frequencies of 16.4% and 19.1%, respectively. In addition, the CRISPR/Cas system induced targeted mutations in Z. mays protoplasts with efficiencies (13.1%) similar to those obtained with TALENs (9.1%). Our results show that both TALENs and the CRISPR/Cas system can be used for genome modification in maize.

  12. Small amounts of ammonium (NH4+) can increase growth of maize (Zea mays)

    KAUST Repository

    George, Jessey

    2016-09-16

    Nitrate (NOequation image) and ammonium (NHequation image) are the predominant forms of nitrogen (N) available to plants in agricultural soils. Nitrate concentrations are generally ten times higher than those of NHequation image and this ratio is consistent across a wide range of soil types. The possible contribution of these small concentrations of NHequation image to the overall N budget of crop plants is often overlooked. In this study the importance of this for the growth and nitrogen budget of maize (Zea mays L.) was investigated, using agriculturally relevant concentrations of NHequation image. Maize inbred line B73 was grown hydroponically for 30 d at low (0.5 mM) and sufficient (2.5 mM) levels of NOequation image. Ammonium was added at 0.05 mM and 0.25 mM to both levels of NOequation image. At low NOequation image levels, addition of NHequation image was found to improve the growth of maize plants. This increased plant growth was accompanied by an increase in total N uptake, as well as total phosphorus, sulphur and other micronutrients in the shoot. Ammonium influx was higher than NOequation image influx for all the plants and decreased as the total N in the nutrient medium increased. This study shows that agriculturally relevant proportions of NHequation image supplied in addition to NOequation image can increase growth of maize.

  13. Biochemical and Photosynthetic Evaluation of Responses in Zea mays L. Under Drought Stress

    Directory of Open Access Journals (Sweden)

    S. S. Abu-Muriefah

    2014-04-01

    Full Text Available Antioxidant defense system(s, pigments content and photosynthetic activity as well as some biochemical changes under drought stress were analyzed in maize (Zea mays L. cv. Giza 21 leaves to determine the response of plant to drought stress and to elucidate the role of various protective mechanisms against oxidative stress. It was found that the application of drought stress led to changes in the carbohydrates and protein contents. Total soluble sugars, accumulated in the leavesof water-stressed plants, whereas, starch and protein contents were dropped to a small amounts compared to the control. Furthermore, plants have well-developed defense systems againstreactive oxygen species (ROS, involving both limiting the formation of ROS as well asinstituting its removal. Within a cell, the activities of a range of antioxidant enzymes suchas superoxide dismutase (SOD, catalase (CAT, ascorbate peroxidase(APX involved in scavenging ROS were investigated. During dehydrationthe SOD, APX and CAT increased significantly up to 4 days, then declined in their activities but still maintained higher than the control levels this indicates that the defense systems involvedare efficient in the protection of plant cells against oxidation. In addition, there was consistent increase in the lipid peroxidation and accumulation of malondialdehyde (MDA. The levels of hydrogen peroxide were also elevated during stressing periods. In this study we are reporting the negative response of maize plants toward drought stress especially on the antioxidant enzymatic activity for the prolonged drought effect.

  14. Nematode suppression and growth stimulation in corn plants (Zea mays L.) irrigated with domestic effluent.

    Science.gov (United States)

    Barros, Kenia Kelly; do Nascimento, Clístenes Williams Araújo; Florencio, Lourdinha

    2012-01-01

    Treated wastewater has great potential for agricultural use due to its concentrations of nutrients and organic matter, which are capable of improving soil characteristics. Additionally, effluents can induce suppression of plant diseases caused by soil pathogens. This study evaluates the effect of irrigation with effluent in a UASB reactor on maize (Zea mays L.) development and on suppression of the diseases caused by nematodes of the genus Meloidogyne. Twelve lysimeters of 1 m(3) each were arranged in a completely randomized design, with four treatments and three replicates. The following treatments were used: T1 (W+I), irrigation with water and infestation with nematodes; T2 (W+I+NPK), irrigation with water, infestation with nematodes and fertilization with nitrogen (N), phosphorus (P) and potassium (K); T3 (E+I), irrigation with effluent and infestation with nematodes; and T4 (E+I+P), irrigation with effluent, infestation with nematodes and fertilization with phosphorus. The plants irrigated with the effluent plus the phosphorus fertilizer had better growth and productivity and were more resistant to the disease symptoms caused by the nematodes. The suppression levels may have been due to the higher levels of Zn and NO(3)(-) found in the leaf tissue of the plants irrigated with the effluent and phosphorus fertilizer.

  15. NUTRIENTS POOL IN CONSORTIA OF Eucalyptus urograndis, Acacia mearnsii AND Zea mays

    Directory of Open Access Journals (Sweden)

    Márcio Viera

    2013-08-01

    Full Text Available http://dx.doi.org/10.5902/1980509810543This study aimed to determine the nutrient pool in monospecific and mixed stands of Eucalyptus urograndis and Acacia mearnsii in a consortium with Zea mays.The amount determination of nutrients of forest species was carried out in the treatments: 100E (100% of eucalyptus; 100A (100% of black wattle and 50E:50A (50% of eucalyptus + 50% of black-wattle. On the other hand, for corn, it was carried out in all treatments (100E; 100A, 50E:50A; 75E:25A – 75% of eucalyptus + 25% black-wattle and 25E:75A – 25% of eucalyptus + 75% of black wattle. The delimitation adopted was the one of a randomized block with three replications. The magnitude of the nutrient pool in the agrossilvicultural systems biomass was: N> K > Ca > Mg > P > S, for macronutrients, and Mn > Fe > Zn > B > Cu, for micronutrients. Due to the great export of nutrients through the corn harvest, residues should be kept and it is necessary to make a nutritional reposition, mainly with P, N, K, S and Zn in the following crops, because of the higher amount that are exported with the extraction of the corn tang, which reaches 75.3; 60.6; 59.9; 55.8 e 53.8%, respectively, in relation to the total stocked in the biomass.

  16. Evolution of Resistance by Helicoverpa zea (Lepidoptera: Noctuidae) Infesting Insecticidal Crops in the Southern United States.

    Science.gov (United States)

    Pan, Zaiqi; Onstad, David; Crain, Philip; Crespo, Andre; Hutchison, William; Buntin, David; Porter, Pat; Catchot, Angus; Cook, Don; Pilcher, Clint; Flexner, Lindsey; Higgins, Laura

    2016-04-01

    We created a deterministic, frequency-based model of the evolution of resistance by corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), to insecticidal traits expressed in crops planted in the heterogeneous landscapes of the southern United States. The model accounts for four generations of selection by insecticidal traits each year. We used the model results to investigate the influence of three factors on insect resistance management (IRM): 1) how does adding a third insecticidal trait to both corn and cotton affect durability of the products, 2) how does unstructured corn refuge influence IRM, and 3) how do block refuges (50% compliance) and blended refuges compare with regard to IRM? When Bt cotton expresses the same number of insecticidal traits, Bt corn with three insecticidal traits provides longer durability than Bt corn with two pyramided traits. Blended refuge provides similar durability for corn products compared with the same level of required block refuge when the rate of refuge compliance by farmers is 50%. Results for Mississippi and Texas are similar, but durabilities for corn traits are surprisingly lower in Georgia, where unstructured corn refuge is the highest of the three states, but refuge for Bt cotton is the lowest of the three states. Thus, unstructured corn refuge can be valuable for IRM but its influence is determined by selection for resistance by Bt cotton.

  17. Computational Study on Substrate Specificity of a Novel Cysteine Protease 1 Precursor from Zea mays

    Directory of Open Access Journals (Sweden)

    Huimin Liu

    2014-06-01

    Full Text Available Cysteine protease 1 precursor from Zea mays (zmCP1 is classified as a member of the C1A family of peptidases (papain-like cysteine protease in MEROPS (the Peptidase Database. The 3D structure and substrate specificity of the zmCP1 is still unknown. This study is the first one to build the 3D structure of zmCP1 by computer-assisted homology modeling. In order to determine the substrate specificity of zmCP1, docking study is used for rapid and convenient analysis of large populations of ligand–enzyme complexes. Docking results show that zmCP1 has preference for P1 position and P2 position for Arg and a large hydrophobic residue (such as Phe. Gly147, Gly191, Cys189, and Asp190 are predicted to function as active residues at the S1 subsite, and the S2 subsite contains Leu283, Leu193, Ala259, Met194, and Ala286. SIFt results indicate that Gly144, Arg268, Trp308, and Ser311 play important roles in substrate binding. Then Molecular Mechanics-Poisson-Boltzmann Surface Area (MM-PBSA method was used to explain the substrate specificity for P1 position of zmCp1. This study provides insights into the molecular basis of zmCP1 activity and substrate specificity.

  18. Perennial aneuploidy as a potential material for gene introgression between maize and Zea perennis

    Institute of Scientific and Technical Information of China (English)

    FU Jie; TANG Qi-lin; YANG Xiu-yan; CHENG Ming-jun; LÜ Gui-hua; WANG Pei; WU Yuan-qi; ZHENG Ming-min; ZHOU Shu-feng; RONG Ting-zhao

    2015-01-01

    Hybridization, which al ows for gene lfow between crops, is dififcult between maize and Zea perennis. In this study, we aim to initiate and study gene lfow between maize and Z. perennis via a special aneuploid plant (MDT) derived from an interspeciifc hybrid of the two species. The chromosome constitution and morphological characters of MDT as wel as certain backcross progenies were examined. Results from genomic in situ hybridization (GISH) indicate that aneuploid MDT consisted of nine maize chromosomes and 30 Z. perennis chromosomes. The backcross progenies of MDT×maize displayed signiifcant diversity of vegetative and ear morphology;several unusual plants with speciifc chromosome constitution were founded in its progenies. Some special perennial progeny with several maize chromosomes were obtained by backcrossing MDT with Z. perennis, and the ifrst whole chromosome introgression from maize to Z. perennis was detected in this study. With this novel material and method, a number of maize-tetraploid teosinte addition or substitution lines can be generated for further study, which has great signiifcance to maize and Z. perennis genetic research, especial y for promoting introgression and transferring desirable traits.

  19. Proteus mirabilis alleviates zinc toxicity by preventing oxidative stress in maize (Zea mays) plants.

    Science.gov (United States)

    Islam, Faisal; Yasmeen, Tahira; Riaz, Muhammad; Arif, Muhammad Saleem; Ali, Shafaqat; Raza, Syed Hammad

    2014-12-01

    Plant-associated bacteria can have beneficial effects on the growth and health of their host. However, the role of plant growth promoting bacteria (PGPR), under metal stress, has not been widely investigated. The present study investigated the possible mandatory role of plant growth promoting rhizobacteria in protecting plants from zinc (Zn) toxicity. The exposure of maize plants to 50µM zinc inhibited biomass production, decreased chlorophyll, total soluble protein and strongly increased accumulation of Zn in both root and shoot. Similarly, Zn enhanced hydrogen peroxide, electrolyte leakage and lipid peroxidation as indicated by malondaldehyde accumulation. Pre-soaking with novel Zn tolerant bacterial strain Proteus mirabilis (ZK1) isolated zinc (Zn) contaminated soil, alleviated the negative effect of Zn on growth and led to a decrease in oxidative injuries caused by Zn. Furthermore, strain ZK1 significantly enhanced the activities of catalase, guaiacol peroxidase, superoxide dismutase and ascorbic acid but lowered the Proline accumulation in Zn stressed plants. The results suggested that the inoculation of Zea mays plants with P. mirabilis during an earlier growth period could be related to its plant growth promoting activities and avoidance of cumulative damage upon exposure to Zn, thus reducing the negative consequences of oxidative stress caused by heavy metal toxicity.

  20. Depth Profiles in Maize ( Zea mays L.) Seeds Studied by Photoacoustic Spectroscopy

    Science.gov (United States)

    Hernández-Aguilar, C.; Domínguez-Pacheco, A.; Cruz-Orea, A.; Zepeda-Bautista, R.

    2015-06-01

    Photoacoustic spectroscopy (PAS) has been used to analyze agricultural seeds and can be applied to the study of seed depth profiles of these complex samples composed of different structures. The sample depth profile can be obtained through the photoacoustic (PA) signal, amplitude, and phase at different light modulation frequencies. The PA signal phase is more sensitive to changes of thermal properties in layered samples than the PA signal amplitude. Hence, the PA signal phase can also be used to characterize layers at different depths. Thus, the objective of the present study was to obtain the optical absorption spectra of maize seeds ( Zea mays L.) by means of PAS at different light modulation frequencies (17 Hz, 30 Hz, and 50 Hz) and comparing these spectra with the ones obtained from the phase-resolved method in order to separate the optical absorption spectra of seed pericarp and endosperm. The results suggest the possibility of using the phase-resolved method to obtain optical absorption spectra of different seed structures, at different depths, without damaging the seed. Thus, PAS could be a nondestructive method for characterization of agricultural seeds and thus improve quality control in the food industry.

  1. Effect of a longitudinally applied voltage upon the growth of Zea mays seedlings

    Science.gov (United States)

    Desrosiers, M. F.; Bandurski, R. S.

    1988-01-01

    The electrical parameters that affect young seedling growth were investigated. Voltages ranging from 5 to 40 volts were applied longitudinally along the mesocotyl region of 4-day old Zea mays L. (cv Silver Queen) seedlings for periods of 3 or 4 hours. It was determined that: (a) making the tips of the seedlings electrically positive relative to the base strongly inhibited shoot growth at 5 volts, whereas the reverse polarity had no effect; (b) at higher voltages, making the tip of the seedlings negative caused less growth inhibition than the reverse polarity at each voltage level; (c) the higher the applied voltage the greater the degree of inhibition; and, (d) the more growth inhibition experienced by the plants the poorer, and slower, their recovery. Previous observations of a relationship between the amount of free indole-3-acetic acid in the mesocotyl cortex and the growth rate of the mesocotyl and of gravitropism-induced movement of labeled indole-3-acetic acid from the seed to the shoot lead to the prediction of a voltage-dependent gating of the movement of indole-3-acetic acid from the stele to the cortex. This provided the basis for attempting to alter the growth rate of seedlings by means of an applied voltage.

  2. Morphometric analysis of epidermal differentiation in primary roots of Zea mays

    Science.gov (United States)

    Moore, R.; Smith, H. S.

    1990-01-01

    Epidermal differentiation in primary roots of Zea mays was divided into six cell types based on cellular shape and cytoplasmic appearance. These six cell types are: 1) apical protoderm, located at the tip of the root pole and characterized by periclinally flattened cells; 2) cuboidal protoderm, located approximately 230 microns from the root pole and characterized by cuboidal cells; 3) tabular epidermis, located approximately 450 microns from the root pole and characterized by anticlinally flattened cells; 4) cuboidal epidermis, located approximately 900 microns from the root pole and characterized by cuboidal cells having numerous small vacuoles; 5) vacuolate cuboidal epidermis, located approximately 1,500 microns from the root pole and characterized by cuboidal cells containing several large vacuoles; and 6) columnar epidermis, located approximately 2,200 microns from the root pole (i.e., at the beginning of the zone of elongation) and characterized by elongated cells. We also used stereology to quantify the cellular changes associated with epidermal differentiation. The quiescent center and the apical protoderm have significantly different ultrastructures. The relative volume of dictyosomes increases dramatically during the early stages of epidermal differentiation. This increase correlates inversely with the amount of coverage provided by the root cap and mucilage.

  3. Morphological and physiological responses of maize (Zea mays) exposed to sand contaminated by phenanthrene.

    Science.gov (United States)

    Dupuy, Joan; Ouvrard, Stéphanie; Leglize, Pierre; Sterckeman, Thibault

    2015-04-01

    Phytoremediation is promising, but depends on clearly understanding contaminants' impact on plant functioning. We therefore focused on the impact of polycyclic aromatic hydrocarbons (PAH) on cultivated plants and understanding the impact of phenanthrene (PHE) on maize functioning (Zea mays). Cultivation was conducted under controlled conditions on artificially contaminated sand with PHE levels increasing from 50 to 750 mg PHE kg(-1). After four weeks, plants exposed to levels above 50 mg PHE kg(-1) presented decreased biomasses and reduced photosynthetic activity. These modifications were associated with higher biomass allocations to roots and lower ones to stems. The leaf biomass proportion was similar, with thinner blades than controls. PHE-exposed plant showed modified root architecture, with fewer roots of 0.2 and 0.4 mm in diameter. Leaves were potassium-deplete, but calcium, phosphorus, magnesium and zinc-enriched. Their content in nitrogen, iron, sulfur and manganese was unaffected. These responses resembled those of water-stress, although water contents in plant organs were not affected by PHE and water supply was not limited. They also indicated a possible perturbation of both nutritional functioning and photosynthesis.

  4. Asymmetric distribution of glucose and indole-3-acetyl-myo-inositol in geostimulated Zea mays seedlings

    Science.gov (United States)

    Momonoki, Y. S.; Bandurski, R. S. (Principal Investigator)

    1988-01-01

    Indole-3-acetyl-myo-inositol occurs in both the kernel and vegetative shoot of germinating Zea mays seedlings. The effect of a gravitational stimulus on the transport of [3H]-5-indole-3-acetyl-myo-inositol and [U-14C]-D-glucose from the kernel to the seedling shoot was studied. Both labeled glucose and labeled indole-3-acetyl-myo-inositol become asymmetrically distributed in the mesocotyl cortex of the shoot with more radioactivity occurring in the bottom half of a horizontally placed seedling. Asymmetric distribution of [3H]indole-3-acetic acid, derived from the applied [3H]indole-3-acetyl-myo-inositol, occurred more rapidly than distribution of total 3H-radioactivity. These findings demonstrate that the gravitational stimulus can induce an asymmetric distribution of substances being transported from kernel to shoot. They also indicate that, in addition to the transport asymmetry, gravity affects the steady state amount of indole-3-acetic acid derived from indole-3-acetyl-myo-inositol.

  5. Starch Mobilization in Ultradried Seed of Maize (Zea mays L.) During Germination

    Institute of Scientific and Technical Information of China (English)

    Xiao-Feng WANG; Xin-Ming JING; Jian LIN

    2005-01-01

    The effects of ultradry storage on the starch mobilization in maize (Zea mays L.) seed after aging were investigated. The results indicated that there were no significant differences in the content of ATP,starch, and soluble sugar, as well as the activity of amylase, between ultradried seeds and seeds stored at -20 ℃ during germination. These results were consistent with the higher level of vigor of the ultradried seed. Sieve tube introduction of a fluorescence dye (carboxyl fluoresceindiacetate) and laser confocal microscopy were used to study the development of plasmodesmata in the ultradried seeds. The results indicated that plasmodesmata developed well in ultradried seeds. Fluorescence analysis also showed that the fluorescence intensity in the radicle of ultradried seeds was stronger than that in seeds with a higher moisture content. This suggests that ultradry treatment has no adverse effects on the seeds. After seed imbibition, cell orgaelles could be resumed. It is concluded that ultradry seed storage is beneficial for maintaining seed vigor and that starchy mobilization proceeds regularly during germination.

  6. Differential expression of superoxide dismutase genes in aphid-stressed maize (Zea mays L.) seedlings.

    Science.gov (United States)

    Sytykiewicz, Hubert

    2014-01-01

    The aim of this study was to compare the expression patterns of superoxide dismutase genes (sod2, sod3.4, sod9 and sodB) in seedling leaves of the Zea mays L. Tasty Sweet (susceptible) and Ambrozja (relatively resistant) cultivars infested with one of two hemipteran species, namely monophagous Sitobion avenae F. (grain aphid) or oligophagous Rhopalosiphum padi L. (bird cherry-oat aphid). Secondarily, aphid-elicited alternations in the antioxidative capacity towards DPPH (1,1-diphenyl-2-picrylhydrazyl) radical in insect-stressed plants were evaluated. Comprehensive comparison of expression profiles of the four sod genes showed that both insect species evoked significant upregulation of three genes sod2, sod3.4 and sod9). However, aphid infestation affected non-significant fluctuations in expression of sodB gene in seedlings of both maize genotypes. The highest levels of transcript accumulation occurred at 8 h (sod2 and sod3.4) or 24 h (sod9) post-infestation, and aphid-induced changes in the expression of sod genes were more dramatic in the Ambrozja cultivar than in the Tasty Sweet variety. Furthermore, bird cherry-oat aphid colonization had a more substantial impact on levels of DPPH radical scavenging activity in infested host seedlings than grain aphid colonization. Additionally, Ambrozja plants infested by either hemipteran species showed markedly lower antioxidative capacity compared with attacked Tasty Sweet plants.

  7. Substrate geometry controls the cyclization cascade in multiproduct terpene synthases from Zea mays.

    Science.gov (United States)

    Vattekkatte, Abith; Gatto, Nathalie; Köllner, Tobias G; Degenhardt, Jörg; Gershenzon, Jonathan; Boland, Wilhelm

    2015-06-07

    Multiproduct terpene synthases TPS4-B73 and TPS5-Delprim from maize (Zea mays) catalyze the conversion of farnesyl diphosphate (FDP) and geranyl diphosphate (GDP) into a complex mixture of sesquiterpenes and monoterpenes, respectively. Various isotopic and geometric isomers of natural substrates like (2Z)-[2-(2)H]- and [2,4,4,9,9,9-(2)H6]-(GDP) and (2Z,6E)-[2-(2)H]- and [2,4,4,13,13,13-(2)H6]-(FDP) were synthesized analogous to presumptive reaction intermediates. On incubation with labeled (2Z) substrates, TPS4 and TPS5 showed much lower kinetic isotope effects than the labeled (2E) substrates. Interestingly, the products arising from the deuterated (2Z)-precursors revealed a distinct preference for cyclic products and exhibited an enhanced turnover on comparison with natural (2E)-substrates. This increase in the efficiency due to (2Z) configuration emphasizes the rate limiting effect of the initial (2E) → (2Z) isomerization step in the reaction cascade of the multiproduct terpene synthases. Apart from turnover advantages, these results suggest that substrate geometry can be used as a tool to optimize the biosynthetic reaction cascade towards valuable cyclic terpenoids.

  8. Exogenous melatonin improves corn (Zea mays L.) embryo proteome in seeds subjected to chilling stress.

    Science.gov (United States)

    Kołodziejczyk, Izabela; Dzitko, Katarzyna; Szewczyk, Rafał; Posmyk, Małgorzata M

    2016-04-01

    Melatonin (MEL; N-acetyl-5-methoxytryptamine) plays an important role in plant stress defense. Various plant species rich in this indoleamine have shown a higher capacity for stress tolerance. Moreover, it has great potential for plant biostimulation, is biodegradable and non-toxic for the environment. All this indicates that our concept of seed enrichment with exogenous MEL is justified. This work concerns the effects of corn (Zea mays L.) seed pre-sowing treatments supplemented with MEL. Non-treated seeds (nt), and those hydroprimed with water (H) or with MEL solutions 50 and 500 μM (HMel50, HMel500) were compared. Positive effects of seed priming are particularly apparent during germination under suboptimal conditions. The impact of MEL applied by priming on seed protein profiles during imbibition/germination at low temperature has not been investigated to date. In order to identify changes in the corn seed proteome after applying hydropriming techniques, purified protein extracts of chilling stressed seed embryos (14 days, 5°C) were separated by two-dimensional electrophoresis. Then proteome maps were graphically and statistically compared and selected protein spots were qualitatively analyzed using mass spectrometry techniques and identified. This study aimed to analyze the priming-induced changes in maize embryo proteome and at identifying priming-associated and MEL-associated proteins in maize seeds subjected to chilling. We attempt to explain how MEL expands plant capacity for stress tolerance.

  9. Expression profiling of selected glutathione transferase genes in Zea mays (L.) seedlings infested with cereal aphids.

    Science.gov (United States)

    Sytykiewicz, Hubert; Chrzanowski, Grzegorz; Czerniewicz, Paweł; Sprawka, Iwona; Łukasik, Iwona; Goławska, Sylwia; Sempruch, Cezary

    2014-01-01

    The purpose of this report was to evaluate the expression patterns of selected glutathione transferase genes (gst1, gst18, gst23 and gst24) in the tissues of two maize (Zea mays L.) varieties (relatively resistant Ambrozja and susceptible Tasty Sweet) that were colonized with oligophagous bird cherry-oat aphid (Rhopalosiphum padi L.) or monophagous grain aphid (Sitobion avenae L.). Simultaneously, insect-triggered generation of superoxide anion radicals (O2•-) in infested Z. mays plants was monitored. Quantified parameters were measured at 1, 2, 4, 8, 24, 48 and 72 h post-initial aphid infestation (hpi) in relation to the non-infested control seedlings. Significant increases in gst transcript amounts were recorded in aphid-stressed plants in comparison to the control seedlings. Maximal enhancement in the expression of the gst genes in aphid-attacked maize plants was found at 8 hpi (gst23) or 24 hpi (gst1, gst18 and gst24) compared to the control. Investigated Z. mays cultivars formed excessive superoxide anion radicals in response to insect treatments, and the highest overproduction of O2•- was noted 4 or 8 h after infestation, depending on the aphid treatment and maize genotype. Importantly, the Ambrozja variety could be characterized as having more profound increments in the levels of gst transcript abundance and O2•- generation in comparison with the Tasty Sweet genotype.

  10. Calcium-regulated in vivo protein phosphorylation in Zea mays L. root tips

    Science.gov (United States)

    Raghothama, K. G.; Reddy, A. S.; Friedmann, M.; Poovaiah, B. W.

    1987-01-01

    Calcium dependent protein phosphorylation was studied in corn (Zea mays L.) root tips. Prior to in vivo protein phosphorylation experiments, the effect of calcium, ethyleneglycol-bis-(beta-aminoethyl ether)-N-N' -tetraacetic acid (EGTA) and calcium ionophore (A-23187) on phosphorus uptake was studied. Calcium increased phosphorus uptake, whereas EGTA and A-23187 decreased it. Consequently, phosphorus concentration in the media was adjusted so as to attain similar uptake in different treatments. Phosphoproteins were analyzed by two-dimensional gel electrophoresis. Distinct changes in phosphorylation were observed following altered calcium levels. Calcium depletion in root tips with EGTA and A-23187 decreased protein phosphorylation. However, replenishment of calcium following EGTA and ionophore pretreatment enhanced phosphorylation of proteins. Preloading of the root tips with 32P in the presence of EGTA and A-23187 followed by a ten minute calcium treatment, resulted in increased phosphorylation indicating the involvement of calcium, calcium and calmodulin-dependent kinases. Calmodulin antagonist W-7 was effective in inhibiting calcium-promoted phosphorylation. These studies suggest a physiological role for calcium-dependent phosphorylation in calcium-mediated processes in plants.

  11. Selection of inbred maize (Zea mays L.) progenies by topcrosses conducted in contrasting environments.

    Science.gov (United States)

    Rodrigues, C S; Pacheco, C A P; Guedes, M L; Pinho, R G V; Castro, C R

    2016-09-23

    The aim of this study was to identify inbred progenies of S0:1 maize (Zea mays L.) plants that were efficient at a low level of technology and responsive at a high level of technology through the use of topcrosses. Two contrasting environments were created using two levels of base fertilization and topdressing, so that the levels of nitrogen, phosphorus, and potassium were applied four times higher in one environment than in the other. We used S0:1 progenies derived from commercial hybrids in topcrosses with two testers (an elite line from the flint heterotic group and an elite line from the dent heterotic group). The progenies and three controls were evaluated in an augmented block design in Nossa Senhora das Dores, SE, Brazil in the 2010 crop season. The average grain yield in the high-technological level was 21.44% greater than that in the low-technological level. There were no changes in progeny behavior in the two technological levels for grain yield. The testers did not differ in the average grain yield of the progenies at the two technological levels. Therefore, it is possible to select progenies derived from commercial hybrids that have an efficient response to fertilization.

  12. Effect of biochar on reclaimed tidal land soil properties and maize (Zea mays L.) response.

    Science.gov (United States)

    Kim, Hyuck-Soo; Kim, Kwon-Rae; Yang, Jae E; Ok, Yong Sik; Owens, Gary; Nehls, Thomas; Wessolek, Gerd; Kim, Kye-Hoon

    2016-01-01

    Reclaimed tidal land soil (RTLS) often contains high levels of soluble salts and exchangeable Na that can adversely affect plant growth. The current study examined the effect of biochar on the physicochemical properties of RTLS and subsequently the influence on plant growth performance. Rice hull derived biochar (BC) was applied to RTLS at three different rates (1%, 2%, and 5% (w/w)) and maize (Zea mays L.) subsequently cultivated for 6weeks. While maize was cultivated, 0.1% NaCl solution was supplied from the bottom of the pots to simulate the natural RTLS conditions. Biochar induced changes in soil properties were evaluated by the water stable aggregate (WSA) percentage, exchangeable sodium percentage (ESP), soil organic carbon contents, cation exchange capacity, and exchangeable cations. Plant response was measured by growth rate, nutrient contents, and antioxidant enzyme activity of ascorbate peroxidase (APX) and glutathione reductase (GR). Application of rice hull derived biochar increased the soil organic carbon content and the percentage of WSA by 36-69%, while decreasing the ESP. The highest dry weight maize yield was observed from soil which received 5% BC (w/w), which was attributed to increased stability of water-stable aggregates and elevated levels of phosphate in BC incorporated soils. Moreover, increased potassium, sourced from the BC, induced mitigation of Na uptake by maize and consequently, reduced the impact of salt stress as evidenced by overall declines in the antioxidant activities of APX and GR.

  13. Evaluation of zinc accumulation, allocation, and tolerance in Zea mays L. seedlings: implication for zinc phytoextraction.

    Science.gov (United States)

    Bashmakov, Dmitry I; Lukatkin, Alexander S; Anjum, Naser A; Ahmad, Iqbal; Pereira, Eduarda

    2015-10-01

    This work investigated the accumulation, allocation, and impact of zinc (Zn; 1.0 μM-10 mM) in maize (Zea mays L.) seedlings under simulated laboratory conditions. Z. mays exhibited no significant change in its habitus (the physical characteristics of plants) up to 10-1000 μM of Zn (vs 5-10 mM Zn). Zn tolerance evaluation, based on the root test, indicated a high tolerance of Z. mays to both low and intermediate (or relatively high) concentrations of Zn, whereas this plant failed to tolerate 10 mM Zn and exhibited a 5-fold decrease in its Zn tolerance. Contingent to Zn treatment levels, Zn hampered the growth of axial organs and brought decreases in the leaf area, water regime, and biomass accumulation. Nevertheless, at elevated levels of Zn (10 mM), Zn(2+) was stored in the root cytoplasm and inhibited both axial organ growth and water regime. However, accumulation and allocation of Zn in Z. mays roots, studied herein employing X-ray fluorimeter and histochemical methods, were close to Zn accumulator plants. Overall, the study outcomes revealed Zn tolerance of Z. mays, and also implicate its potential role in Zn phytoextraction.

  14. Response of maize (Zea mays L. saccharata Sturt) to different concentration treatments of deltamethrin.

    Science.gov (United States)

    Duran, Ragbet Ezgi; Kilic, Semra; Coskun, Yasemin

    2015-10-01

    The aim of this study was to investigate the effect of the deltamethrin pesticide on the biological properties of maize (Zea mays L. saccharata Sturt). Maize seeds were exposed to environmentally relevant dosages (0.01, 0.05, 0.1 and 0.5 ppm) of deltamethrin. On the 7th day of germination, morphological, anatomical and physiological responses were determined. All seedling growth characters were decreased with increasing deltamethrin levels. The most negative effect on the radicle length of maize was observed by the highest deltamethrin concentration with a 61% decrease (P <0.05). Both stomatal density and stomatal dimension reduction were caused by increasing concentrations of deltamethrin. Moreover, the pigments like chlorophyll a, chlorophyll b, total chlorophyll and caretonoids decreased with the increase in deltamethrin concentration. Conversely, anthocyanin and proline content increased in parallel with deltamethrin concentration. As a result, all morphological traits and pigments except for proline and anthocyanin were significantly reduced with an increase in pesticide concentration, compared to control (P <0.05).

  15. Comparative effectiveness of metal ions in inducing curvature of primary roots of Zea mays

    Science.gov (United States)

    Hasenstein, K. H.; Evans, M. L.; Stinemetz, C. L.; Moore, R.; Fondren, W. M.; Koon, E. C.; Higby, M. A.; Smucker, A. J.

    1988-01-01

    We used five cultivars of Zea mays (Bear Hybrid WF9 * 38MS, B73 * Missouri 17, Yellow Dent, Merit, and Great Lakes Hybrid 422) to reinvestigate the specificity of metal ions for inducing root curvature. Of 17 cations tested, 6 (Al3+, Ba2+, Ca2+, Cd2+, Cu2+, Zn2+) induced curvature. Roots curved away from Al3+, Ba2+, and Cd2+. Roots curved away from low (0.1 millimolar) concentrations of Cu2+ but toward higher (1-5 millimolar) concentrations. Roots initially curved away from Zn2+ but the direction of the subsequent curvature was unpredictable. In most cases, roots of all cultivars curved towards calcium. However, in some tests there was no response to calcium or even (especially in the cultivars Merit and B73 * Missouri 17) substantial curvature away from calcium. The results indicate that the induction of root curvature is not specific for calcium. The results are discussed relative to the possible role of calmodulin as a mediator of ion-induced root curvature.

  16. Plant species coexistence alleviates the impacts of lead on Zea mays L.

    Institute of Scientific and Technical Information of China (English)

    Ruyi Yang; Ling Liu; Shuting Zan; Jianjun Tang; Xin Chen

    2012-01-01

    Whether plant coexistence can reduce the impacts of lead(Pb)on crops in agroecosystems has not been well understood.We conducted a factorial experiment to investigate the effects of weeds coexisting with maize(Zea mays L.)on Pb accumulation in maize and soil microbes at two Pb levels(ambient and 300 mg/kg).Elevated Pb tended to increase the Pb concentration in maize and decreased soil microbial activity(indicated by the average well color development,AWCD),functional group diversity,as well as arbuscular mycorrhizal(AM)colonization and vesicle number of maize.Compared to the monoculture,weeds coexisting with maize reduced the Pb concentrations in the root,leaf,sheath and stem of maize at both seedling and mature stages.In maize-weed mixtures,soil microbial activity and functional group diversity tended to increase for both Pb treatments relative to the monoculture.Furthermore,principal component analysis revealed that the soil microbial community structure changed with the introduction of weeds.The highest Pb accumulation in weeds occurred for the elevated Pb treatment in a three species mixture.The results suggest that multiple plant species coexistence could reduce lead accumulation in crop plants and alleviate the negative impacts on soil microbes in polluted land,thereby highlighting the significance of plant diversity in agroecosystems.

  17. [Systematically induced effects of Tetranychus cinnabarinus infestation on chemical defense in Zea mays inbred lines].

    Science.gov (United States)

    Zhu, Yu-xi; Yang, Qun-fang; Huang, Yu-bi; Li, Qing

    2015-09-01

    In the present study, we investigated the systematically induced production of defense-related compounds, including DIMBOA, total phenol, trypsin inhibitors (TI) and chymotrypsin inhibitor (CI), by Tetranychus cinnabarinus infestation in Zea mays. The first leaves of two corn in-bred line seedlings, the mite-tolerant line ' H1014168' and the mite-sensitive line 'H1014591', were sucked by T. cinnabarinus adult female for seven days, and then the contents of DIMBOA, total phenol, TI and CI were measured in the second leaf and in the roots, respectively. Results showed that as compared to the unsucked control, all contents of DIMBOA, total phenol, TI and CI induced by T. cinnabarinus sucking were significantly higher in the second leaf of both inbred lines as well as in the roots of the mite-tolerant 'H1014168'. However, in the roots of 'H1014591', these defense compounds had different trends, where there was a higher induction of TI and a lower level of total phenol than that of the healthy control, while had almost no difference in DIMBOA and CI. These findings suggested that the infestation of T. cinnabarinus could systematically induce accumulation of defense-related compounds, and this effect was stronger in the mite-tolerant inbred line than in the mite-sensitive inbred line.

  18. Cytochemical localization of calcium in cap cells of primary roots of Zea mays L

    Science.gov (United States)

    Moore, R.

    1986-01-01

    The distribution of calcium (Ca) in caps of vertically- and horizontally-oriented roots of Zea mays was monitored to determine its possible role in root graviresponsiveness. A modification of the antimonate precipitation procedure was used to localize Ca in situ. In vertically-oriented roots, the presumed graviperceptive (i.e., columella) cells were characterized by minimal and symmetric staining of the plasmalemma and mitochondria. No precipitate was present in plasmodesmata or cell walls. Within 5 min after horizontal reorientation, staining was associated with the portion of the cell wall adjacent to the distal end of the cell. This asymmetric staining persisted throughout the onset of gravicurvature. No staining of lateral cell walls of columella cells was observed at any stage of gravicurvature, suggesting that a lateral flow of Ca through the columella tissue of horizontally-oriented roots does not occur. The outermost peripheral cells of roots oriented horizontally and vertically secrete Ca through plasmodesmata-like structures in their cell walls. These results are discussed relative to proposed roles of root-cap Ca in root gravicurvature.

  19. Corn (Zea mays growth in petroleum contaminated soil, remediated with orange (Citrus sinensis peel extract

    Directory of Open Access Journals (Sweden)

    Tomás Darío Marín Veláquez

    2016-09-01

    Full Text Available Soil pollution has a strong impact when oil activity takes place within a savanna ecosystem. Any oil spill affects agricultural soils. Biostimulation with orange peel extract (Citrus sinensis is an alternative for remediation of soil contaminated with crude oil and in this research the corn plant (Zea mays was used as a biomarker of contamination level of a savanna soil after their treatment. Three samples of savannah soil contaminated with oil light crude were treated with dissolutions 1, 3 and 5% of extract of orange peel in water at a dose of 150 mL per kg of soil treated. The content of oils and fats was measured every 7 days, up to 42 days. Corn seeds were planted in soil samples, their growth was measured every 5 days for a period of 35 consecutive days, comparing their growth with seeds planted in a soil sample without contamination. According to an analysis of rank contrast, the plant growth was statistically the same in all samples up to 20 days; from there, evident differences regarding the pattern were shown.

  20. Quantitative trait loci for mercury accumulation in maize (Zea mays L.) identified using a RIL population.

    Science.gov (United States)

    Fu, Zhongjun; Li, Weihua; Zhang, Qinbin; Wang, Long; Zhang, Xiaoxiang; Song, Guiliang; Fu, Zhiyuan; Ding, Dong; Liu, Zonghua; Tang, Jihua

    2014-01-01

    To investigate the genetic mechanism of mercury accumulation in maize (Zea mays L.), a population of 194 recombinant inbred lines derived from an elite hybrid Yuyu 22, was used to identify quantitative trait loci (QTLs) for mercury accumulation at two locations. The results showed that the average Hg concentration in the different tissues of maize followed the order: leaves > bracts > stems > axis > kernels. Twenty-three QTLs for mercury accumulation in five tissues were detected on chromosomes 1, 4, 7, 8, 9 and 10, which explained 6.44% to 26.60% of the phenotype variance. The QTLs included five QTLs for Hg concentration in kernels, three QTLs for Hg concentration in the axis, six QTLs for Hg concentration in stems, four QTLs for Hg concentration in bracts and five QTLs for Hg concentration in leaves. Interestingly, three QTLs, qKHC9a, qKHC9b, and qBHC9 were in linkage with two QTLs for drought tolerance. In addition, qLHC1 was in linkage with two QTLs for arsenic accumulation. The study demonstrated the concentration of Hg in Hg-contaminated paddy soil could be reduced, and maize production maintained simultaneously by selecting and breeding maize Hg pollution-safe cultivars (PSCs).

  1. Quantitative trait loci for mercury accumulation in maize (Zea mays L. identified using a RIL population.

    Directory of Open Access Journals (Sweden)

    Zhongjun Fu

    Full Text Available To investigate the genetic mechanism of mercury accumulation in maize (Zea mays L., a population of 194 recombinant inbred lines derived from an elite hybrid Yuyu 22, was used to identify quantitative trait loci (QTLs for mercury accumulation at two locations. The results showed that the average Hg concentration in the different tissues of maize followed the order: leaves > bracts > stems > axis > kernels. Twenty-three QTLs for mercury accumulation in five tissues were detected on chromosomes 1, 4, 7, 8, 9 and 10, which explained 6.44% to 26.60% of the phenotype variance. The QTLs included five QTLs for Hg concentration in kernels, three QTLs for Hg concentration in the axis, six QTLs for Hg concentration in stems, four QTLs for Hg concentration in bracts and five QTLs for Hg concentration in leaves. Interestingly, three QTLs, qKHC9a, qKHC9b, and qBHC9 were in linkage with two QTLs for drought tolerance. In addition, qLHC1 was in linkage with two QTLs for arsenic accumulation. The study demonstrated the concentration of Hg in Hg-contaminated paddy soil could be reduced, and maize production maintained simultaneously by selecting and breeding maize Hg pollution-safe cultivars (PSCs.

  2. Characterization and Fine Mapping of a Necrotic Leaf Mutant in Maize (Zea mays L.)

    Institute of Scientific and Technical Information of China (English)

    Lijing Wang; Shuai Han; Shiyi Zhong; Haizhong Wei; Yanjun Zhang; Yan Zhao; Baoshen Liu

    2013-01-01

    Maize (Zea mays L.) is a commercially important crop.Its yield can be reduced by mutations in biosynthetic and degradative pathways that cause death.In this paper,we describe the necrotic leaf (nec-t) mutant,which was obtained from an inbred line,81647.The nec-t mutant plants had yellow leaves with necrotic spots,reduced chlorophyll content,and the etiolated seedlings died under normal growth conditions.Transmission electron microscopy revealed scattered thylakoids,and reduced numbers of grana lamellae and chloroplasts per cell.Histochemical staining suggested that spot formation of nec-t leaves might be due to cell death.Genetic analysis showed that necrosis was caused by the mutation of a recessive locus.Using simple sequence repeat markers,the Nec-t gene was mapped between mmc0111 and bnlg2277 on the short arm of chromosome 2.A total of 1287 individuals with the mutant phenotype from a F2 population were used for physical mapping.The Nec-t gene was located between markers T31 and H8 within a physical region of 131.7 kb.

  3. Characteristics and functional properties of purple corn (Zea mays L. var. subnigroviolaceo

    Directory of Open Access Journals (Sweden)

    Jhoseline Guillén-Sánchez

    2014-09-01

    Full Text Available Zea Mays L. variety purple (purple corn is a plant native of America, which has the episperm seeds (grains and the cobs (cob in purple, which gives special characteristics to the pigments that have (between 1.5% and 6.0%, called anthocyanins, which belong to the group of flavonoids. Due to its high content of anthocyanins (cianin C3G-3-glucose as its main color and phenolic compounds act as powerful natural antioxidant and anticancer, Further having functional properties due to these bioactive compounds. The purple corn also provides significant amounts of starch, about 80% (complex carbohydrate, 10% of sugars provide sweetness, up to 11% protein, up to 2% minerals and B vitamins and ascorbic acid, concentrated in endosperm (grain free envelope. Also the nutritional value, the purple corn has a rich composition of phytochemicals, which have beneficial effects on our body, such as neutralize free radicals and act as antimutagenic. His review paper aimed to collect information on the studies undertaken to purple corn as an alternative to artificial food dyes and health benefits when included in the diet. Benefits such as cardiovascular diseases (hypertension, lowering cholesterol, fighting diabetes, being the most remarkable antioxidant action (wrinkle.

  4. Azospirillum brasilense does not affect population structure of specific rhizobacterial communities of inoculated maize (Zea mays).

    Science.gov (United States)

    Herschkovitz, Yoav; Lerner, Anat; Davidov, Yaacov; Okon, Yaacov; Jurkevitch, Edouard

    2005-11-01

    Positive response of plant species to plant growth-promoting rhizobacteria have led to an increased interest in their use as bacterial inoculants. However, the introduction of exogenous bacteria into natural ecosystems may perturb bacterial populations within the microbial community and lead to the disruption of indigenous populations performing key functional roles. In this study the effect of Azospirillum brasilense inoculation on maize (Zea mays) rhizosphere Actinobacteria, Bacteroidetes, alpha-Proteobacteria, Pseudomonas and Bdellovibrio spp. was assessed using a polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) approach in conjunction with group-specific primers. The DGGE fingerprints analysis revealed that the introduction of A. brasilense did not alter or disrupt the microbial system at the group-specific level. However, some communities such as the alpha-Proteobacteria and Bdellovibrio were influenced by plant age while the other bacterial groups remained unaffected. Based on these as well as previous data, it can be inferred that inoculation with A. brasilense does not perturb the natural bacterial populations investigated.

  5. Neonicotinoid-Coated Zea mays Seeds Indirectly Affect Honeybee Performance and Pathogen Susceptibility in Field Trials.

    Directory of Open Access Journals (Sweden)

    Mohamed Alburaki

    Full Text Available Thirty-two honeybee (Apis mellifera colonies were studied in order to detect and measure potential in vivo effects of neonicotinoid pesticides used in cornfields (Zea mays spp on honeybee health. Honeybee colonies were randomly split on four different agricultural cornfield areas located near Quebec City, Canada. Two locations contained cornfields treated with a seed-coated systemic neonicotinoid insecticide while the two others were organic cornfields used as control treatments. Hives were extensively monitored for their performance and health traits over a period of two years. Honeybee viruses (brood queen cell virus BQCV, deformed wing virus DWV, and Israeli acute paralysis virus IAPV and the brain specific expression of a biomarker of host physiological stress, the Acetylcholinesterase gene AChE, were investigated using RT-qPCR. Liquid chromatography-mass spectrometry (LC-MS was performed to detect pesticide residues in adult bees, honey, pollen, and corn flowers collected from the studied hives in each location. In addition, general hive conditions were assessed by monitoring colony weight and brood development. Neonicotinoids were only identified in corn flowers at low concentrations. However, honeybee colonies located in neonicotinoid treated cornfields expressed significantly higher pathogen infection than those located in untreated cornfields. AChE levels showed elevated levels among honeybees that collected corn pollen from treated fields. Positive correlations were recorded between pathogens and the treated locations. Our data suggests that neonicotinoids indirectly weaken honeybee health by inducing physiological stress and increasing pathogen loads.

  6. The effect of bottom sediment supplement on heavy metals content in plants (Zea mays and soil

    Directory of Open Access Journals (Sweden)

    Baran A.

    2013-04-01

    Full Text Available Important aspect of bottom sediments is the problem of their management or disposal after their extraction from the bottom of rivers, dam reservoirs, ports, channels or ponds. The research aimed at an assessment of potential environmental management of bottom sediment used as an admixture to light soil basing on its effect on contents of heavy metals in plants and soil. The research was conducted on light soil with granulometric structure of weakly loamy sand. The bottom sediment was added to light soil in the amount of 0 (control 5, 10, 30 i 50%. The test plant was maize (Zea mays, “Bora” c.v. The sediment applied in the presented research revealed high share of silt and clay fractions, alkaline pH and low contents of heavy metals, therefore it may be used as an admixture to the above mentioned soils to improve their productivity. The applied bottom sediment to the soil affected a decreased in Zn, Cd and Pb content in maize in comparison with the treatment without the deposit whereas increased content of Cu, Cr and Ni. No exceeded permissible content of heavy metals concerning plant assessment in view of their forage usability were registered in maize biomass.

  7. Effect of salt stress on some sweet corn (Zea mays L. var. saccharata genotypes

    Directory of Open Access Journals (Sweden)

    Shtereva Lydia A.

    2015-01-01

    Full Text Available An experiment was carried out hydroponically under laboratory conditions to investigate the effect of salt stress on several physiological and biochemical parameters of three sweet corn (Zea mays L. var. saccharata genotypes: lines 6-13, C-6 (pollen source and their heterotic F1 hybrid “Zaharina”. The degree of salinity tolerance among these genotypes was evaluated at three different sodium chloride (NaCl concentrations: 0 mM, 100 mM, 125 mM and 150 mM. Seed germination, plant growth and biochemical stress determining parameters such as malondialdehyde (MDA, proline content and hydrogen peroxide (H2O2 levels were compared between seedlings of lines and hybrid. The obtained results indicated that both lines and hybrid have similar responses at different salinity levels for all examined traits. All the seedlings’ growth parameters, such as germination percentage, root length, shoot length, root and shoot fresh and dry weight, decreased with increasing salinity level. MDA, proline and H2O2 increased at different saline conditions in comparison to the control. Based on the results, of the three genotypes examined, the hybrid Zaharina, followed by line C-6, was more salt-sensitive than line 6-13 in salt stress condition.

  8. Influence of Corn (Zea mays L. Cultivar Development on Grain Nutrient Concentration

    Directory of Open Access Journals (Sweden)

    Carla Fernanda Ferreira

    2012-01-01

    Full Text Available While corn productivity has been increased by the adoption of high-yield hybrids, there are concerns that increased grain potential may be associated with diminished grain nutrient concentration. Ten corn (Zea mays L. cultivars representing five technological levels (landrace variety, commercial variety, and double, triple, and single cross-hybrids were cropped on a Rhodic Ferralsol Eutric soil with high fertility in 2006 (dry year and 2007 (normal year in Rolândia County, Brazil. At maturity, grain was evaluated for concentrations of P, K, Ca, Mg, Fe, Mn, Zn, and Cu. In general, differences among cultivars were noted for all nutrients in both years. Concentrations of P, K, Fe, and Mn were lower in the dry year, while Ca, Mg, Cu, and Zn were higher. Soil water availability appeared to exert more influence on grain nutrient concentration than did cultivar development; nutrient removal due to grain harvest was also greatly influenced by rainfall patterns and their impact on corn productivity. Even though genetic differences were noted, which may be useful to breeding programs, long-term testing in subtropical environments will be required to clarify the interaction between genetics and climate events on grain nutrient quality and exportation.

  9. Identification and characterization of the RCI2 gene family in maize (Zea mays)

    Indian Academy of Sciences (India)

    Yang Zhao; Haiqing Tong; Ronghao Cai; Xiaojian Peng; Xiaoyu Li; Defang Gan; Suwen Zhu

    2014-12-01

    Rare-cold-inducible (RCI2) genes are structurally conserved members that encode small, highly hydrophobic proteins involved in response to various abiotic stresses. Phylogenetic and functional analyses of these genes have been conducted in Arabidopsis, but an extensive investigation of the RCI2 gene family has not yet been carried out in maize. In the present study, 10 RCI2 genes were identified in a fully sequenced maize genome. Structural characterization and expression pattern analysis of 10 ZmRCI2s (Zea mays RCI2 genes) were subsequently determined. Sequence and phylogenetic analyses indicated that ZmRCI2s are highly conserved, and most of them could be grouped with their orthologues from other organisms. Chromosomal location analysis indicated that ZmRCI2s were distributed unevenly on seven chromosomes with two segmental duplication events, suggesting that maize RCI2 gene family is an evolutionarily conserved family. Putative stress-responsive cis-elements were detected in the 2-kb promoter regions of the 10 ZmRCI2s. In addition, the 10 ZmRCI2s showed different expression patterns in maize development based on transcriptome analysis. Further, microarray and quantitative real-time PCR (qRT-PCR) analysis showed that each maize RCI2 genes were responsive to drought stress, suggesting their important roles in drought stress response. The results of this work provide a basis for future cloning and application studies of maize RCI2 genes.

  10. Neonicotinoid-Coated Zea mays Seeds Indirectly Affect Honeybee Performance and Pathogen Susceptibility in Field Trials

    Science.gov (United States)

    Alburaki, Mohamed; Boutin, Sébastien; Mercier, Pierre-Luc; Loublier, Yves; Chagnon, Madeleine; Derome, Nicolas

    2015-01-01

    Thirty-two honeybee (Apis mellifera) colonies were studied in order to detect and measure potential in vivo effects of neonicotinoid pesticides used in cornfields (Zea mays spp) on honeybee health. Honeybee colonies were randomly split on four different agricultural cornfield areas located near Quebec City, Canada. Two locations contained cornfields treated with a seed-coated systemic neonicotinoid insecticide while the two others were organic cornfields used as control treatments. Hives were extensively monitored for their performance and health traits over a period of two years. Honeybee viruses (brood queen cell virus BQCV, deformed wing virus DWV, and Israeli acute paralysis virus IAPV) and the brain specific expression of a biomarker of host physiological stress, the Acetylcholinesterase gene AChE, were investigated using RT-qPCR. Liquid chromatography-mass spectrometry (LC-MS) was performed to detect pesticide residues in adult bees, honey, pollen, and corn flowers collected from the studied hives in each location. In addition, general hive conditions were assessed by monitoring colony weight and brood development. Neonicotinoids were only identified in corn flowers at low concentrations. However, honeybee colonies located in neonicotinoid treated cornfields expressed significantly higher pathogen infection than those located in untreated cornfields. AChE levels showed elevated levels among honeybees that collected corn pollen from treated fields. Positive correlations were recorded between pathogens and the treated locations. Our data suggests that neonicotinoids indirectly weaken honeybee health by inducing physiological stress and increasing pathogen loads. PMID:25993642

  11. Protein Changes in Response to Pyrene Stress in Maize (Zea mays L.) Leaves

    Institute of Scientific and Technical Information of China (English)

    Sheng-You Xu; Ying-Xu Chen; Wei-Xiang Wu; Shao-Jian Zheng; Sheng-Guo Xue; Shi-Ying Yang; Yi-Jin Peng

    2007-01-01

    Phytoremediation is a relatively new approach to remove polycyclic aromatic hydrocarbons (PAHs) from the environment. When plants are grown under pyrene treatment, they respond by synthesizing a set of protective proteins. To learn more about protein changes in response to pyrene treatment, we extracted total proteins from the leaves of maize (Zea mays L.) 1 week after pyrene treatment. The proteins extracted were separated with twodimensional gel electrophoresis. In total, approximately 54 protein spots were found by comparing gels from treated and control groups. According to the isoelectric point, molecular weight, and abundance of these protein spots, 20 pyrene-induced proteins were found to have changed abundance. Of these, 15 protein spots were increased and five protein spots were newly appeared in pyrene-treated plant leaves. Six model upregulated protein spots of different molecular weights were excised from the gels and subjected to trypsin digestion followed by peptide separation using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Peptlde masses were used to search the matrix-science database for protein identification. Two of the proteins were identified on the basis of the homology of their peptide profiles with existing protein sequences as pyruvate orthophosphate dikinase and the rlbulose-1,5-bisphosphate carboxylase/oxygenase large subunit. These proteins are involved in the regulation of carbohydrate and energy metabolism. The present study gives new insights into the pyrene stress response in maize leaves and demonstrates the power of the proteomlc approach in phytoremediation of PAHs.

  12. Genomewide analysis of LATERAL ORGAN BOUNDARIES Domain gene family in Zea mays

    Indian Academy of Sciences (India)

    Yue-Min Zhang; Shi-Zhong Zhang; Cheng-Chao Zheng

    2014-04-01

    The investigation of transcription factor (TF) families is a major focus of postgenomic research. The plant-specific ASYMMETRIC LEAVES2-LIKE (ASL) / LATERAL ORGAN BOUNDARIES Domain (LBD) proteins constitute a major zincfinger-like-domain transcription factor family, and regulate diverse biological processes in plants. However, little is known about LBD genes in maize (Zea mays). In this study, a total of 44 LBD genes were identified in maize genome and were phylogenetically clustered into two groups (I and II), together with LBDs from Arabidopsis. The predicted maize LBDs were distributed across all the 10 chromosomes with different densities. In addition, the gene structures of maize LBDs were analysed. The expression profiles of the maize LBD genes under normal growth conditions were analysed by microarray data and qRT-PCR. The results indicated that LBDs might be involved in various aspects of physiological and developmental processes in maize. To our knowledge, this is the first report of a genomewide analysis of the maize LBD gene family, which would provide valuable information for understanding the classification and putative functions of the gene family.

  13. Characterization and expression of an antifungal zeamatin-like protein (Zlp) gene from Zea mays.

    Science.gov (United States)

    Malehorn, D E; Borgmeyer, J R; Smith, C E; Shah, D M

    1994-12-01

    A cDNA clone encoding a basic thaumatin-like protein of Zea mays was recovered from a mid-development seed cDNA library. The gene, Zlp, encoded a protein that was nearly identical with maize zeamatin and alpha-amylase/trypsin inhibitor. Expression of Zlp mRNA was highest in the endosperm tissue of seed 4 weeks after pollination. Expression of zeamatin-like (ZLP) protein correlated with mRNA; also, a low basal level of ZLP expression in leaf was not appreciably induced by abiotic stresses. ZLP was expressed with its own signal peptide in insect cells and in transgenic Arabidopsis and tomato plants. ZLP was secreted in all three systems, with correct processing of the signal peptide. ZLP expressed in transgenic tomato was found to be partially subjected to a proteolytic cleavage after residue 180, by an unknown mechanism, to give a "nicked" isoform of ZLP. Purified ZLP from all three sources, as well as purified "nicked" ZLP from tomato, demonstrated fungal inhibition against Candida albicans and Trichoderma reesei, with marginal inhibition observed against Alternaria solani and Neurospora crassa.

  14. Compositional equivalency of Cry1F corn event TC6275 and conventional corn (Zea mays L.).

    Science.gov (United States)

    Herman, Rod A; Phillips, Amy M; Collins, Randy A; Tagliani, Laura A; Claussen, Fred A; Graham, Christopher D; Bickers, Brenda L; Harris, Travis A; Prochaska, Lee M

    2004-05-01

    Maize (Zea mays L.) plants have been transformed to express a Cry1F insecticidal crystal protein originally isolated from Bacillus thuringiensis Berliner. This protein controls lepidopteran pests of maize, including the European corn borer, Ostrinia nubilalis (Hübner). As part of the safety assessment for crops containing transgenes, a compositional analysis of the food and feed is conducted. This analysis is designed to detect unintended changes in the nutrient and antinutrient content of the raw commodities produced by the crop due to the insertion of the genes into the genomic DNA of the plant (pleotropic effects). Samples of transgenic and nontransgenic maize forage and grain were collected from six field sites located in the U.S. and Canada. Forage samples were analyzed for proximates and minerals, and grain was further analyzed for fatty acids, amino acids, vitamins, secondary metabolites, and antinutrients. Results demonstrated that maize expressing the Cry1F protein was equivalent to nontransgenic maize with respect to these important components. Comparison of the variability within the nontransgenic and transgenic hybrid, as compared to composition values reported in the literature, suggest that factors other than transgenes may contribute more substantially to the composition of crops.

  15. Root cap removal increases root penetration resistance in maize (Zea mays L).

    Science.gov (United States)

    Iijima, Morio; Higuchi, Toshifumi; Barlow, Peter W; Bengough, A Glyn

    2003-09-01

    The root cap assists the passage of the root through soil by means of its slimy mucilage secretion and by the sloughing of its outer cells. The root penetration resistance of decapped primary roots of maize (Zea mays L. cv. Mephisto) was compared with that of intact roots in loose (dry bulk density 1.0 g cm-3; penetration resistance 0.06 MPa) and compact soil (1.4 g cm-3; penetration resistance 1.0 MPa), to evaluate the contribution of the cap to decreasing the impedance to root growth. Root elongation rate and diameter were the same for decapped and intact roots when the plants were grown in loose soil. In compacted soil, however, the elongation rate of decapped roots was only about half that of intact roots, whilst the diameter was 30% larger. Root penetration resistances of intact and decapped seminal axis were 0.31 and 0.52 MPa, respectively, when the roots were grown in compacted soil. These results indicated that the presence of a root cap alleviates much of the mechanical impedance to root penetration, and enables roots to grow faster in compacted soils.

  16. Cytogenetics of monosomes in Zea mays. Progress report, May 16, 1979-May 15, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Weber, D. F.

    1980-02-01

    Monosomics lack a pairing partner in each meiotic cell, and genes on an entire chromosome are present in the hemizygous condition. Monosomics for chromosomes 1, 2, 3, 4, 6, 7, 8, 9, and 10 in Zea mays have been isolated. This is the only series of this type that has been recovered in any diploid organism. The monosomic plants are vigorous, good cytological samples can be taken, and crosses can be made. All possible monosomic types are being isolated and characterized by studying: (1) the cytology of meiosis; (2) the cytological behavior of univalent chromosomes; (3) the effect of monosomy and trisomy on intergenic and intragenic recombination; (4) the frequency and types of spontaneous chromosomal aberrations arising in monosomics; (5) the effect of aneuploidy on the relative amounts of specific fatty acids in embryos; (6) monosomic mutational mapping; and (7) metabolic profile analysis of monosomics. Systems in maize to detect the environmental and genetic induction of non-disjunction are also being developed. By comparing a monosomic with its disomic siblings, one compares one and two copies of all genes on an entire chromosome. If a gene expressing dosage effects resides on a specific chromosome, a difference will be found between a plant monosomic for that chromosome and its diploid siblings. Genetic factors that control the meiotic process, genetic recombination, lipid biosynthesis, and the free amino acid pool have been discovered.

  17. Cytogenetics of monosomes in Zea mays. Progress report, May 16, 1980-May 15, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Weber, D. F.

    1981-02-01

    Monosomics lack a pairing partner in each meiotic cell, and genes on an entire chromosome are present in the hemizygous condition. We have isolated monosomics for chromosomes 1, 2, 3, 4, 6, 7, 8, 9, and 10 in Zea mays utilizing a recently-discovered system. This is the only series of this type that has been recovered in any diploid organism. The monosomic plants are surprisingly vigorous, good cytological samples can be taken, and crosses can be made. We are isolating all possible monosomic types and characterizing them by studying: (1) the cytology of meiosis, (2) the cytological behavior of univalent chromosomes, (3) the effect of monosomy and trisomy on intergenic and intragenic recombination, (4) the frequency and types of spontaneous chromosomal aberrations arising in monosomics, (5) the effect of aneuploidy on the relative amounts of specific fatty acids in embryos, (6) monosomic mutational mapping, (7) the effect of monosomy on pollen exine morphology with the scanning electron microscope, and (8) the effect of monosomy on DIMBOA levels. We are also developing test systems utilizing maize to detect the environmental or genetic induction of non-disjunction. This study has discovered genetic factors that control the meiotic process, genetic recombination, lipid biosynthesis, and the free amino acid pool.

  18. Detection of Cell Wall Chemical Variation in Zea Mays Mutants Using Near-Infrared Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Buyck, N.; Thomas, S.

    2001-01-01

    Corn stover is regarded as the prime candidate feedstock material for commercial biomass conversion in the United States. Variations in chemical composition of Zea mays cell walls can affect biomass conversion process yields and economics. Mutant lines were constructed by activating a Mu transposon system. The cell wall chemical composition of 48 mutant families was characterized using near-infrared (NIR) spectroscopy. NIR data were analyzed using a multivariate statistical analysis technique called Principal Component Analysis (PCA). PCA of the NIR data from 349 maize leaf samples reveals 57 individuals as outliers on one or more of six Principal Components (PCs) at the 95% confidence interval. Of these, 19 individuals from 16 families are outliers on either PC3 (9% of the variation) or PC6 (1% of the variation), the two PCs that contain information about cell wall polymers. Those individuals for which altered cell wall chemistry is confirmed with wet chemical analysis will then be subjected to fermentation analysis to determine whether or not biomass conversion process kinetics, yields and/or economics are significantly affected. Those mutants that provide indications for a decrease in process cost will be pursued further to identify the gene(s) responsible for the observed changes in cell wall composition and associated changes in process economics. These genes will eventually be incorporated into maize breeding programs directed at the development of a truly dual use crop.

  19. The nitrate reductase inhibitor, tungsten, disrupts actin microfilaments in Zea mays L.

    Science.gov (United States)

    Adamakis, Ioannis-Dimosthenis S; Panteris, Emmanuel; Eleftheriou, Eleftherios P

    2014-05-01

    Tungsten is a widely used inhibitor of nitrate reductase, applied to diminish the nitric oxide levels in plants. It was recently shown that tungsten also has heavy metal attributes. Since information about the toxic effects of tungsten on actin is limited, and considering that actin microfilaments are involved in the entry of tungsten inside plant cells, the effects of tungsten on them were studied in Zea mays seedlings. Treatments with sodium tungstate for 3, 6, 12 or 24 h were performed on intact seedlings and seedlings with truncated roots. Afterwards, actin microfilaments in meristematic root and leaf tissues were stained with fluorescent phalloidin, and the specimens were examined by confocal laser scanning microscopy. While the actin microfilament network was well organized in untreated seedlings, in tungstate-treated ones it was disrupted in a time-dependent manner. In protodermal root cells, the effects of tungsten were stronger as cortical microfilaments were almost completely depolymerized and the intracellular ones appeared highly bundled. Fluorescence intensity measurements confirmed the above results. In the meristematic leaf tissue of intact seedlings, no depolymerization of actin microfilaments was noticed. However, when root tips were severed prior to tungstate application, both cortical and endoplasmic actin networks of leaf cells were disrupted and bundled after 24 h of treatment. The differential response of root and leaf tissues to tungsten toxicity may be due to differential penetration and absorption, while the effects on actin microfilaments could not be attributed to the nitric oxide depletion by tungsten.

  20. Climate Change Adaptation: Real Time Nitrogen Management in Maize (Zea Mays L. Using Leaf Colour Chart

    Directory of Open Access Journals (Sweden)

    R. K. Mathukia

    2014-12-01

    Full Text Available A field experiment was conducted at Instructional Farm, College of Agriculture, Junagadh Agricultural University, Junagadh during rabi 2011-12 and 2012-13 to study the real time nitrogen management using leaf colour chart (LCC in maize (Zea mays L.. Basal dose of 20-50 kg N-P2O5/ha was applied in all the treatments. Top dressing of 60 or 80 N in form of Urea in two splits at LCC 2, 3, 4 and 5 were compared with fixed time N application [50 kg N/ha at 30 DAS + 30 kg N/ha at 60 days after sowing (DAS]. Top dressing of 50 kg N/ha + 30 kg N/ha when LCC=4 or LCC=5 significantly improved growth and yield attributes viz., plant height, dry matter accumulation/plant, number of leaves/plant, stem diameter, number of internodes/ plant, leaf area index, cob length, cob girth, number of cobs/plant, number of grains/cob, grain weight/plant and 1000-grain weight along with higher grain and stover yields, grain protein content and economic returns over fixed time application of 50 kg N/ha at 30 DAS + 30 kg N/ha at 60 DAS.

  1. Responses of Different Physiological Indices for Maize (Zea mays) to Soil Water Availability

    Institute of Scientific and Technical Information of China (English)

    WU Yuan-Zhi; HUANG Ming-Bin; D. N. WARRINGTON

    2011-01-01

    Knowledge of plant responses to soil water availability is essential for the development of efficient irrigation strategies.However,notably different results have been obtained in the past on the responses of various physiological indices for different plants to soil water availability.In this study,the responses of various plant processes to soil water availability were compared with data from pot and field plot experiments conducted on maize (Zea mays L.).Consistent results were obtained between pot and field plot experiments for the responses of various relative plant indices to changes in the fraction of available soil water (FASW).A threshold value,where the relative plant indices began to decrease with soil drying,and a lower water limit,where the decline of relative plant indices changed to a very slow rate,were found.Evaporative demand not only influenced the transpiration rate over a daily scale but also determined the difference in transpirational response to soil water availability among the transient,daily and seasonal time scales.At the seasonal scale,cumulative transpiration decreased linearly with soil drying,but the decrease of transpiration from FASW =1 in response to water deficits did not affect dry weight until FASW =0.75.On the other hand,the decrease in dry weight was comparable with plant height and leaf area.Therefore,the plant responses to soil water availability were notably different among various plant indices of maize and were influenced by the weather conditions.

  2. A multidrug resistance-associated protein involved in anthocyanin transport in Zea mays.

    Science.gov (United States)

    Goodman, Christopher Dean; Casati, Paula; Walbot, Virginia

    2004-07-01

    Anthocyanin biosynthesis is one of the most thoroughly studied enzymatic pathways in biology, but little is known about the molecular mechanisms of its final stage: the transport of the anthocyanin pigment into the vacuole. We have identified a multidrug resistance-associated protein (MRP), ZmMrp3, that is required for this transport process in maize (Zea mays). ZmMrp3 expression is controlled by the regulators of anthocyanin biosynthesis and mirrors the expression of other anthocyanin structural genes. Localization of ZmMRP3 in vivo shows its presence in the tonoplast, the site at which anthocyanin transport occurs. Mutants generated using antisense constructs have a distinct pigmentation phenotype in the adult plant that results from a mislocalization of the pigment as well as significant reduction in anthocyanin content, with no alteration in the anthocyanin species produced. Surprisingly, mutant plants did not show a phenotype in the aleurone. This appears to reflect the presence of a second, highly homologous gene, ZmMrp4, that is also coregulated with the anthocyanin pathway but is expressed exclusively in aleurone tissue. This description of a plant MRP with a role in the transport of a known endogenous substrate provides a new model system for examining the biological and biochemical mechanisms involved in the MRP-mediated transport of plant secondary metabolites.

  3. Open Field Study of Some Zea mays Hybrids, Lipid Compounds and Fumonisins Accumulation

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    Paola Giorni

    2015-09-01

    Full Text Available Lipid molecules are increasingly recognized as signals exchanged by organisms interacting in pathogenic and/or symbiotic ways. Some classes of lipids actively determine the fate of the interactions. Host cuticle/cell wall/membrane components such as sphingolipids and oxylipins may contribute to determining the fate of host–pathogen interactions. In the present field study, we considered the relationship between specific sphingolipids and oxylipins of different hybrids of Zea mays and fumonisin by F. verticillioides, sampling ears at different growth stages from early dough to fully ripe. The amount of total and free fumonisin differed significantly between hybrids and increased significantly with maize ripening. Oxylipins and phytoceramides changed significantly within the hybrids and decreased with kernel maturation, starting from physiological maturity. Although the correlation between fumonisin accumulation and plant lipid profile is certain, the data collected so far cannot define a cause-effect relationship but open up new perspectives. Therefore, the question—“Does fumonisin alter plant lipidome or does plant lipidome modulate fumonisin accumulation?”—is still open.

  4. Cloning and Functional Characterization of the Maize (Zea mays L. Carotenoid Epsilon Hydroxylase Gene.

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    Shu Chang

    Full Text Available The assignment of functions to genes in the carotenoid biosynthesis pathway is necessary to understand how the pathway is regulated and to obtain the basic information required for metabolic engineering. Few carotenoid ε-hydroxylases have been functionally characterized in plants although this would provide insight into the hydroxylation steps in the pathway. We therefore isolated mRNA from the endosperm of maize (Zea mays L., inbred line B73 and cloned a full-length cDNA encoding CYP97C19, a putative heme-containing carotenoid ε hydroxylase and member of the cytochrome P450 family. The corresponding CYP97C19 genomic locus on chromosome 1 was found to comprise a single-copy gene with nine introns. We expressed CYP97C19 cDNA under the control of the constitutive CaMV 35S promoter in the Arabidopsis thaliana lut1 knockout mutant, which lacks a functional CYP97C1 (LUT1 gene. The analysis of carotenoid levels and composition showed that lutein accumulated to high levels in the rosette leaves of the transgenic lines but not in the untransformed lut1 mutants. These results allowed the unambiguous functional annotation of maize CYP97C19 as an enzyme with strong zeinoxanthin ε-ring hydroxylation activity.

  5. Efecto vasodilatador mediado por óxido nítrico del extracto hidroalcohólico de Zea mays L. (maíz morado en anillos aórticos de rata Vasodilator effect mediated by nitric oxide of the Zea mays L (andean purple corn hydroalcoholic extract in aortic rings of rat

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    Oscar Moreno-Loaiza

    2010-12-01

    Full Text Available Objetivo. Evaluar la respuesta vasodilatadora e inhibidora de la vasoconstricción del extracto hidroalcohólico de Zea mays L. (maíz morado y determinar si esta respuesta es mediada por óxido nítrico (NO. Materiales y métodos. Se obtuvo un extracto de las corontas de maíz morado maceradas durante ocho días en etanol al 70%, y posterior concentración del producto. Se trabajó con anillos aórticos de rata en cámara de órganos aislados, bañada con solución Krebs-Hensleit (K-H y se registró la actividad vasomotora con un transductor de tensión isométrica. Se produjo una contracción basal con KCl 120 mM sobre la cual determinó el efecto vasodilatador de tres dosis del extracto: 0,1; 0,5 y 1,0 mg/mL. Se utilizó L-NG-Nitroarginina metil ester (L-NAME para comprobar que la vasodilatación depende de la óxido nítrico sinteasa (NOs. Luego se comparó la inhibición de la contracción vascular tras la incubación durante 30 minutos, con extracto de maíz morado y captopril 10-5 M. Resultados. Se observó una reducción de la contracción máxima (100% a 85,25 ± 2,60%, 77,76 ± 3,23% y 73,3 ± 4,87%, para las dosis de 0,1; 0,5 y 1,0 mg/mL, respectivamente. La vasodilatación fue inhibida por la incubación previa con L-NAME. El extracto de maíz morado no inhibió la contracción vascular, a diferencia del captopril (reducción a 75,27 ± 8,61%. Conclusión. El extracto hidroalcohólico de Zea mays L produce vasodilatación dependiente de la síntesis de NO.Objective: To evaluate the vasodilator response of the hydroalcoholic extract of Zea mays L. (Andean purple corn and to determine if this response is mediated by nitric oxide (NO. Material and methods: We obtained an extract by maceration for eight days of Andean purple corn cobs in 70% ethanol and subsequent concentration of the product. Thoracic aortic rings were evaluated in an isolated organ chamber, bathed with Krebs-Hensleit solution (KH, and vasomotor activity was recorded

  6. Sobre Humanismo y Medicina

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    Adolfo de Francisco Zea

    2000-12-01

    Full Text Available

    En esta disertación sobre “Humanismo y Medicina”, título del libro que tuve ocasión de publicar hace un par de años, destacaré algunas de las relaciones que existen entre la medicina y las bellas artes, concretamente la música y la pintura. La Medicina tiene como objeto de su acción al Hombre. Definida como la ciencia y el arte de prevenir, curar o aliviar la enfermedad, no tiene como meta la simple prolongación de la vida biológica.

    Su tarea consiste en postergar la muerte, prevenir o reducir los padecimientos y las deformidades, curar las enfermedades, ampliar las capacidades biológicas y psicológicas de los seres humanos y ocuparse de los sufrimientos de las personas. Para Tristam Engelhardt, es la Medicina de las personas.

    Se concibe a la persona humana como el individuo de conciencia reflexiva normal que es a la vez miembro pleno de la comunidad, con los deberes y derechos que presuponen su pertenencia a ella. A esta acepción de carácter moral de la persona humana, que corresponde a lo que se llama persona “en sentido estricto”, se agrega la acepción social, que hace relación con aquellas personas a las que se otorgan prácticamente los mismos derechos, como es el caso de los niños, de los individuos que perdieron el carácter de personas por padecer de lesiones cerebrales o demencia, y de aquellos que nunca llegarán a serlo como los retrasados mentales profundos.

    Al sostener que no todos los seres humanos son personas “en sentido estricto”, la Bioética que expone Engelhardt impone, sin embargo, como obligación moral, tratar a estos últimos con pleno respeto y comprensión. Lo que es importante acerca de nosotros mismos como seres humanos, es el hecho real de que seamos personas; no simplemente nuestra pertenencia al género Horno sapiens como tal.

    Para Víctor Frankl, la persona humana es de carácter espiritual y en tal virtud, es diferente del organismo psicofísico cuya

  7. Acueducto pretensado sobre el Holme

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    Editorial, Equipo

    1958-04-01

    Full Text Available Breve descripción del paso de una canalización de 0,60 m de diámetro, destinada al abastecimiento de aguas, sobre el río Holme (Inglaterra. El puente formado tiene dos vigas de hormigón pretensado, cuyas armaduras se componen de barras McCall.

  8. Comparisons on Forage Yield and Feeding Value Between Zea mexicana,Yucao2 and Chuandan14-Zea mexicana Hybrid%玉草2号、川单14×墨西哥大刍草和墨西哥大刍草产量和饲用价值比较

    Institute of Scientific and Technical Information of China (English)

    冯云超; 唐祈林; 荣廷昭

    2011-01-01

    To understand the forage yields in different planting density as well as their feeding value in the optimum density, a field experiment which Zea mexicana and Zea mays -Zea mexicana hybrids (Yucao2 and Chuan-danl4 × Zea mexicana) used as the materials were designed by random block split plot design investigated. The main results were that the fresh and dry matter yields of the three forages, which showed the change of "low-high-low" with the increase of planting density. The fresh and dry matter yields were the highest in the Yucao2 and the lowest in Zea mexicana among all planting density. The yields of crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF) and ether extract(EE) in Yucao2 and chuandanl4× Zea Mexicana were higher than in Zea mexicana significantly or high significant, however, the content of CP and EE was the highest in Zea Mexicana. The relative feeding value(RFV) in Yucao2 had no significance with that in Zea mexicana and were higher than in chuandanl4 × Zea mexicana significantly.%采用裂区设计,对不同种植密度下玉草2号、川单14×墨西哥大刍草和墨西哥大刍草产量以及最适密度下饲用价值进行研究.结果表明,在试验设计的密度下,玉草2号鲜、干草产量均最高,川单14×墨西哥大刍草其次,墨西哥大刍草最低;3种饲草其鲜、干草产量随密度增加呈"低-高-低"的变化趋势.最适密度下饲用价值比较表明,玉草2号和川单14×墨西哥大刍草粗蛋白、酸性洗涤纤维、中性洗涤纤维和粗脂肪4种饲用成分产量均显著或极显著高于墨西哥大刍草,其粗蛋白和粗脂肪含量均低于墨西哥大刍草;玉草2号和墨西哥大刍草相对饲用价值差异不显著,均显著高于川单14×墨西哥大刍草.

  9. Survivorship of Helicoverpa zea and Heliothis virescens on cotton plant structures expressing a Bacillus thuringiensis vegetative insecticidal protein.

    Science.gov (United States)

    Bommireddy, P L; Leonard, B R

    2008-08-01

    A series of tests quantified bollworm, Helicoverpa zea (Boddie), and tobacco budworm, Heliothis virescens (F.), larval survival on plant structures of a nontransgenic cotton (Gossypium hirsutum L.), 'Coker 312', and two transgenic cottons expressing Vip3A protein or both Vip3A + CrylAb proteins (VipCot). Vegetative and reproductive structures including terminal leaves, flower bud (square) bracts, whole debracted squares, flower petals, flower anthers, and intact capsules (bolls) were harvested from plants in field plots. Each structure was infested with 2-d-old larvae from one of the two heliothine species. Larvae were allowed to feed for 96 h on fresh tissue. Survivorship at 96 h after infestation was significantly lower on all structures of Vip3A and VipCot cotton lines compared with similar structures of Coker 312. VipCot plant structures generally resulted in lower larval survivorship compared with similar structures of the Vip3A cotton line. H. zea survivorship ranged from 4 to 28% and from 1 to 18% on Vip3A and VipCot plant structures, respectively. H. virescens survivorship ranged from 10 to 43% and from 2 to 12% on Vip3A and VipCot plant structures, respectively. H. virescens survivorship was higher on VIP3A plant structures compared with that for H. zea on similar structures. These differences between species were not observed on plants from the cotton line expressing VipCot proteins. The results for these plant structures demonstrate that the combination of proteins expressed in VipCot cotton lines are more effective than Vip3A cotton lines against this heliothine complex.

  10. Demographics and genetic variability of the new world bollworm (Helicoverpa zea) and the old world bollworm (Helicoverpa armigera) in Brazil.

    Science.gov (United States)

    Leite, Natália A; Alves-Pereira, Alessandro; Corrêa, Alberto S; Zucchi, Maria I; Omoto, Celso

    2014-01-01

    Helicoverpa armigera is one of the primary agricultural pests in the Old World, whereas H. zea is predominant in the New World. However, H. armigera was first documented in Brazil in 2013. Therefore, the geographical distribution, range of hosts, invasion source, and dispersal routes for H. armigera are poorly understood or unknown in Brazil. In this study, we used a phylogeographic analysis of natural H. armigera and H. zea populations to (1) assess the occurrence of both species on different hosts; (2) infer the demographic parameters and genetic structure; (3) determine the potential invasion and dispersal routes for H. armigera within the Brazilian territory; and (4) infer the geographical origin of H. armigera. We analyzed partial sequence data from the cytochrome c oxidase subunit I (COI) gene. We determined that H. armigera individuals were most prevalent on dicotyledonous hosts and that H. zea were most prevalent on maize crops, based on the samples collected between May 2012 and April 2013. The populations of both species showed signs of demographic expansion, and no genetic structure. The high genetic diversity and wide distribution of H. armigera in mid-2012 are consistent with an invasion period prior to the first reports of this species in the literature and/or multiple invasion events within the Brazilian territory. It was not possible to infer the invasion and dispersal routes of H. armigera with this dataset. However, joint analyses using sequences from the Old World indicated the presence of Chinese, Indian, and European lineages within the Brazilian populations of H. armigera. These results suggest that sustainable management plans for the control of H. armigera will be challenging considering the high genetic diversity, polyphagous feeding habits, and great potential mobility of this pest on numerous hosts, which favor the adaptation of this insect to diverse environments and control strategies.

  11. Demographics and genetic variability of the new world bollworm (Helicoverpa zea and the old world bollworm (Helicoverpa armigera in Brazil.

    Directory of Open Access Journals (Sweden)

    Natália A Leite

    Full Text Available Helicoverpa armigera is one of the primary agricultural pests in the Old World, whereas H. zea is predominant in the New World. However, H. armigera was first documented in Brazil in 2013. Therefore, the geographical distribution, range of hosts, invasion source, and dispersal routes for H. armigera are poorly understood or unknown in Brazil. In this study, we used a phylogeographic analysis of natural H. armigera and H. zea populations to (1 assess the occurrence of both species on different hosts; (2 infer the demographic parameters and genetic structure; (3 determine the potential invasion and dispersal routes for H. armigera within the Brazilian territory; and (4 infer the geographical origin of H. armigera. We analyzed partial sequence data from the cytochrome c oxidase subunit I (COI gene. We determined that H. armigera individuals were most prevalent on dicotyledonous hosts and that H. zea were most prevalent on maize crops, based on the samples collected between May 2012 and April 2013. The populations of both species showed signs of demographic expansion, and no genetic structure. The high genetic diversity and wide distribution of H. armigera in mid-2012 are consistent with an invasion period prior to the first reports of this species in the literature and/or multiple invasion events within the Brazilian territory. It was not possible to infer the invasion and dispersal routes of H. armigera with this dataset. However, joint analyses using sequences from the Old World indicated the presence of Chinese, Indian, and European lineages within the Brazilian populations of H. armigera. These results suggest that sustainable management plans for the control of H. armigera will be challenging considering the high genetic diversity, polyphagous feeding habits, and great potential mobility of this pest on numerous hosts, which favor the adaptation of this insect to diverse environments and control strategies.

  12. Inhibition of Helicoverpa zea (Lepidoptera: Noctuidae) Growth by Transgenic Corn Expressing Bt Toxins and Development of Resistance to Cry1Ab.

    Science.gov (United States)

    Reisig, Dominic D; Reay-Jones, Francis P F

    2015-08-01

    Transgenic corn, Zea mays L., that expresses the Bacillus thuringiensis (Bt) toxin Cry1Ab is only moderately toxic to Helicoverpa zea (Boddie) and has been planted commercially since 1996. Growth and development of H. zea was monitored to determine potential changes in susceptibility to this toxin over time. Small plots of corn hybrids expressing Cry1F, Cry1F × Cry1Ab, Cry1Ab × Cry3Bb1, Cry1A.105 × Cry2Ab2 × Cry3Bb1, Cry1A.105 × Cry2Ab2, and Vip3Aa20 × Cry1Ab × mCry3A were planted in both 2012 and 2013 inNorth and South Carolina with paired non-Bt hybrids from the same genetic background. H. zea larvae were sampled on three time periods from ears and the following factors were measured: kernel area injured (cm(2)) by H. zea larvae, larval number per ear, larval weight, larval length, and larval head width. Pupae were sampled on a single time period and the following factors recorded: number per ear, weight, time to eclosion, and the number that eclosed. There was no reduction in larval weight, number of insect entering the pupal stadium, pupal weight, time to eclosion, and number of pupae able to successfully eclose to adulthood in the hybrid expressing Cry1Ab compared with a non-Bt paired hybrid. As Cry1Ab affected these in 1996, H. zea may be developing resistance to Cry1Ab in corn, although these results are not comprehensive, given the limited sampling period, size, and geography. We also found that the negative impacts on larval growth and development were greater in corn hybrids with pyramided traits compared with single traits.

  13. Zea mays iRS1563: a comprehensive genome-scale metabolic reconstruction of maize metabolism.

    Science.gov (United States)

    Saha, Rajib; Suthers, Patrick F; Maranas, Costas D

    2011-01-01

    The scope and breadth of genome-scale metabolic reconstructions have continued to expand over the last decade. Herein, we introduce a genome-scale model for a plant with direct applications to food and bioenergy production (i.e., maize). Maize annotation is still underway, which introduces significant challenges in the association of metabolic functions to genes. The developed model is designed to meet rigorous standards on gene-protein-reaction (GPR) associations, elementally and charged balanced reactions and a biomass reaction abstracting the relative contribution of all biomass constituents. The metabolic network contains 1,563 genes and 1,825 metabolites involved in 1,985 reactions from primary and secondary maize metabolism. For approximately 42% of the reactions direct literature evidence for the participation of the reaction in maize was found. As many as 445 reactions and 369 metabolites are unique to the maize model compared to the AraGEM model for A. thaliana. 674 metabolites and 893 reactions are present in Zea mays iRS1563 that are not accounted for in maize C4GEM. All reactions are elementally and charged balanced and localized into six different compartments (i.e., cytoplasm, mitochondrion, plastid, peroxisome, vacuole and extracellular). GPR associations are also established based on the functional annotation information and homology prediction accounting for monofunctional, multifunctional and multimeric proteins, isozymes and protein complexes. We describe results from performing flux balance analysis under different physiological conditions, (i.e., photosynthesis, photorespiration and respiration) of a C4 plant and also explore model predictions against experimental observations for two naturally occurring mutants (i.e., bm1 and bm3). The developed model corresponds to the largest and more complete to-date effort at cataloguing metabolism for a plant species.

  14. β-aminobutyric acid mediated drought stress alleviation in maize (Zea mays L.).

    Science.gov (United States)

    Shaw, Arun K; Bhardwaj, Pardeep K; Ghosh, Supriya; Roy, Sankhajit; Saha, Suman; Sherpa, Ang R; Saha, Samir K; Hossain, Zahed

    2016-02-01

    The present study highlights the role of β-aminobutyric acid (BABA) in alleviating drought stress effects in maize (Zea mays L.). Chemical priming was imposed by pretreating 1-week-old plants with 600 μM BABA prior to applying drought stress. Specific activities of key antioxidant enzymes and metabolites (ascorbate and glutathione) levels of ascorbate-glutathione cycle were studied to unravel the priming-induced modulation of plant defense system. Furthermore, changes in endogenous ABA and JA concentrations as well as mRNA expressions of key genes involved in their respective biosynthesis pathways were monitored in BABA-primed (BABA+) and non-primed (BABA-) leaves of drought-challenged plants to better understand the mechanistic insights into the BABA-induced hormonal regulation of plant response to water-deficit stress. Accelerated stomatal closure, high relative water content, and less membrane damage were observed in BABA-primed leaves under water-deficit condition. Elevated APX and SOD activity in non-primed leaves found to be insufficient to scavenge all H2O2 and O2 (·-) resulting in oxidative burst as evident after histochemical staining with NBT and DAB. A higher proline accumulation in non-primed leaves also does not give much protection against drought stress. Increased GR activity supported with the enhanced mRNA and protein expressions might help the BABA-primed plants to maintain a high GSH pool essential for sustaining balanced redox status to counter drought-induced oxidative stress damages. Hormonal analysis suggests that in maize, BABA-potentiated drought tolerance is primarily mediated through JA-dependent pathway by the activation of antioxidant defense systems while ABA biosynthesis pathway also plays an important role in fine-tuning of drought stress response.

  15. Growth responses of plants to various concentrations of nitrogen dioxide. [Helianthus annuus L. ; Zea mays L

    Energy Technology Data Exchange (ETDEWEB)

    Okano, K.; Totsuka, T.; Fukuzawa, T.; Tazaki, T.

    1985-01-01

    Sunflower Helianthus annuus L. and maize Zea mays L. plants in the vegetative phase were exposed to nitrogen dioxide (NO2) at 0.0 (control), 0.2, 0.5 and 1.0 ppm ( l liter ) for 2 weeks. The growth responses of the plants to NO2 were examined by the techniques of growth analysis. The sunflower plant was more susceptible to NO2 than the maize plant. Exposure to NO2 at 0.2 ppm slightly stimulated the growth of the sunflower plants. The net assimilation rate (NAR) was also significantly increased when the plants were exposed to 0.2 ppm NO2. Exposures to NO2 at 0.5 or more significantly reduced the dry weight of the sunflower plant. Of the component parts, the roots and stems were severely affected, while the leaves were less affected. This resulted in an elevated shoot/root ratio. The net assimilation rate of both species was reduced by the exposures to NO2 at 0.5 ppm or more, while, in contrast, the leaf area ratio (LAR) was increased. The relative growth rate (RGR), the product of the NAR and the LAR, was therefore less affected by NO2. The increase in the LAR was overwhelmingly the result of an increase in the leaf weight ratio (LWR). These results imply that a reduction in photosynthetic efficiency induced by NO2 could be, in part, compensated for by an increase in assimilatory area, suggesting an adaptive growth response of the plants to air pollutant stresses.

  16. Calcium ion dependency of ethylene production in segments of primary roots of Zea mays

    Science.gov (United States)

    Hasenstein, K. H.; Evans, M. L.

    1986-01-01

    We investigated the effect of Ca2+ on ethylene production in 2-cm long apical segments from primary roots of corn (Zea mays L., B73 x Missouri 17) seedlings. The seedlings were raised under different conditions of Ca2+ availability. Low-Ca and high-Ca seedlings were raised by soaking the grains and watering the seedlings with distilled water or 10 mM CaCl2, respectively. Segments from high-Ca roots produced more than twice as much ethylene as segments from low-Ca roots. Indoleacetic acid (IAA; 1 micromole) enhanced ethylene production in segments from both low-Ca and high-Ca roots but auxin-induced promotion of ethylene production was consistently higher in segments from high-Ca roots. Addition of 1-aminocyclopropane-1-carboxylic acid (ACC) to root segments from low-Ca seedlings doubled total ethylene production and the rate of production remained fairly constant during a 24 h period of monitoring. In segments from high-Ca seedlings ACC also increased total ethylene production but most of the ethylene was produced within the first 6 h. The data suggest that Ca2+ enhances the conversion of ACC to ethylene. The terminal 2 mm of the root tip were found to be especially important to ethylene biosynthesis by apical segments and, experiments using 45Ca2+ as tracer indicated that the apical 2 mm of the root is the region of strongest Ca2+ accumulation. Other cations such as Mn2+, Mg2+, and K+ could largely substitute for Ca2+. The significance of these findings is discussed with respect to recent evidence for gravity-induced Ca2+ redistribution and its relationship to the establishment of asymmetric growth during gravitropic curvature.

  17. Transport and metabolism of indole-3-acetyl-myo-inositol-galactoside in seedlings of Zea mays

    Science.gov (United States)

    Komoszynski, M.; Bandurski, R. S.

    1986-01-01

    Indole-3-acetyl-myo-inositol galactoside labeled with 3H in the indole and 14C in the galactose moieties was applied to kernels of 5 day old germinating seedlings of Zea mays. Indole-3-acetyl-myo-inositol galactoside was not transported into either the shoot or root tissue as the intact molecule but was instead hydrolyzed to yield [3H]indole-3-acetyl-myo-inositol and [3H]indole-3-acetic acid which were then transported to the shoot with little radioactivity going to the root. With certain assumption concerning the equilibration of applied [3H]indole-3-acetyl-myo-inositol-[U-14C]galactose with the endogenous pool, it may be concluded that indole-3-acetyl-myo-inositol galactoside in the endosperm supplies about 2 picomoles per plant per hour of indole-3-acetyl-myo-inositol and 1 picomole per plant per hour of indole-3-acetic acid to the shoot and thus is comparable to indole-3-acetyl-myo-inositol as a source of indole-acetic acid for the shoot. Quantitative estimates of the amount of galactose in the kernels suggest that [3H]indole-3-acetyl-myo-inositol-[14C]galactose is hydrolyzed after the compound leaves the endosperm but before it reaches the shoot. In addition, [3H]indole-3-acetyl-myo-inositol-[14C]galactose supplies appreciable amounts of 14C to the shoot and both 14C and 3H to an uncharacterized insoluble fraction of the endosperm.

  18. Hydrogen sulphide improves adaptation of Zea mays seedlings to iron deficiency.

    Science.gov (United States)

    Chen, Juan; Wu, Fei-Hua; Shang, Yu-Ting; Wang, Wen-Hua; Hu, Wen-Jun; Simon, Martin; Liu, Xiang; Shangguan, Zhou-Ping; Zheng, Hai-Lei

    2015-11-01

    Hydrogen sulphide (H2S) is emerging as a potential molecule involved in physiological regulation in plants. However, whether H2S regulates iron-shortage responses in plants is largely unknown. Here, the role of H2S in modulating iron availability in maize (Zea mays L. cv Canner) seedlings grown in iron-deficient culture solution is reported. The main results are as follows: Firstly, NaHS, a donor of H2S, completely prevented leaf interveinal chlorosis in maize seedlings grown in iron-deficient culture solution. Secondly, electron micrographs of mesophyll cells from iron-deficient maize seedlings revealed plastids with few photosynthetic lamellae and rudimentary grana. On the contrary, mesophyll chloroplasts appeared completely developed in H2S-treated maize seedlings. Thirdly, H2S treatment increased iron accumulation in maize seedlings by changing the expression levels of iron homeostasis- and sulphur metabolism-related genes. Fourthly, phytosiderophore (PS) accumulation and secretion were enhanced by H2S treatment in seedlings grown in iron-deficient solution. Indeed, the gene expression of ferric-phytosiderophore transporter (ZmYS1) was specifically induced by iron deficiency in maize leaves and roots, whereas their abundance was decreased by NaHS treatment. Lastly, H2S significantly enhanced photosynthesis through promoting the protein expression of ribulose-1,5-bisphosphate carboxylase large subunit (RuBISCO LSU) and phosphoenolpyruvate carboxylase (PEPC) and the expression of genes encoding RuBISCO large subunit (RBCL), small subunit (RBCS), D1 protein (psbA), and PEPC in maize seedlings grown in iron-deficient solution. These results indicate that H2S is closely related to iron uptake, transport, and accumulation, and consequently increases chlorophyll biosynthesis, chloroplast development, and photosynthesis in plants.

  19. Optical Reflectance and Fluorescence for Detecting Nitrogen Needs in Zea mays L.

    Science.gov (United States)

    McMurtrey, J. E.; Middleton, E. M.; Corp. L. A.; Campbell, P. K. Entcheva; Butcher, L. M.; Daughtry, C. S. T.

    2003-01-01

    Nitrogen (N) status in field grown corn (Zea mays L.) was assessed using spectral techniques. Passive reflectance remote sensing and, both passive and active fluorescence sensing methods were investigated. Reflectance and fluorescence methods are reported to detect changes in the primary plant pigments (chlorophylls a and b; carotenoids) in higher plant species. As a general rule, foliar chlorophyll a (Chl a) and chlorophyll b (Chl b) usually exist in approx.3:l ratio. In plants under stress, Chl b content is affected before Chl a reductions occur. For reflectance, a version of the chlorophyll absorption in reflectance index (CARI) method was tested with narrow bands from the Airborne Imaging Spectroradiometer for Applications (ASIA). CARI minimizes the effects of soil background on the signal from green canopies. A modified CARI (MCARI) was used to track total Chl a levels in the red dip of the spectrum from the corn canopy. A second MCARI was used to track the auxiliary plant pigments (Chl b and the carotenoids) in the yellow/orange/red edge part of the reflectance spectrum. The difference between these two MCARI indices detected variations in N levels across the field plot canopies using ASIA data. At the leaf level, ratios of fluorescence emissions in the blue, green, red and far-red wavelengths sensed responses that were associated with the plant pigments, and were indicative of energy transfer in the photosynthetic process. N stressed corn stands could be distinguish from those with optimally applied N with fluorescence emission spectra obtained from individual corn leaves. Both reflectance and fluorescence methods are sensitive in detecting corn N needs and may be especially powerful in monitoring crop conditions if both types of information can be combined.

  20. Chelant-assisted phytoextraction and accumulation of Zn by Zea mays.

    Science.gov (United States)

    Gheju, M; Stelescu, I

    2013-10-15

    Zea mays plants were exposed to soils with concentrations of Zn ranging from 64 to 1800 mg kg(-1) dw, and the efficiency of three selected chelating agents (trisodium citrate (CI), disodium oxalate (OX) and disodium dihydrogen ethylene-diamine-tetraacetate (EDTA)) in enhancing metal phytoextraction was compared. Zn concentration in plant tissues increased in conjunction with the metal concentration of the soil. EDTA was found to be the most efficient chelating amendment, increasing concentrations of Zn in shoots from 88 mg kg(-1) dw, at 64 mg kg(-1) dw soil, to 8026 mg kg(-1) dw at 1800 mg kg(-1) dw soil. The overall orders of BCFs and TFs which resulted from this study are: EDTA > H2O > OX > CI, and EDTANa2 > OX > CI > H2O, respectively. The more effective uptake of Zn by plants for the control treatment (distilled water only) than for CI and OX was attributed to the neutral or slightly alkaline pH of the two chelant irrigation solutions. Instead, EDTA had a favorable effect on Zn uptake from soil due to its additive chelating and acidifying properties. Among the three chelants, only EDTA significantly increased the Zn phytoextraction potential of Z. mays, while CI and OX induced a low metal uptake from soil by plants. Although Z. mays has a lower Zn accumulation capacity than the hyperaccumulator Thlaspi caerulescens, it could be considered as a potential phytoremediator of soils with elevated Zn concentrations, especially when metal pollution extends to depths greater than 20 cm.

  1. Correlations between gravitropic curvature and auxin movement across gravistimulated roots of Zea mays

    Science.gov (United States)

    Young, L. M.; Evans, M. L.; Hertel, R.

    1990-01-01

    We compared the kinetics of auxin redistribution across the caps of primary roots of 2-day-old maize (Zea mays, cv Merit) seedlings with the time course of gravitropic curvature. [3H] indoleacetic acid was applied to one side of the cap in an agar donor and radioactivity moving across the cap was collected in an agar receiver applied to the opposite side. Upon gravistimulation the roots first curved upward slightly, then returned to the horizontal and began curving downward, reaching a final angle of about 67 degrees. Movement of label across the caps of gravistimulated roots was asymmetric with preferential downward movement (ratio downward/upward = ca. 1.6, radioactivity collected during the 90 min following beginning of gravistimulation). There was a close correlation between the development of asymmetric auxin movement across the root cap and the rate of curvature, with both values increasing to a maximum and then declining as the roots approached the final angle of curvature. In roots preadapted to gravity (alternate brief stimulation on opposite flanks over a period of 1 hour) the initial phase of upward curvature was eliminated and downward bending began earlier than for controls. The correlation between asymmetric auxin movement and the kinetics of curvature also held in comparisons between control and preadapted roots. Both downward auxin transport asymmetry and downward curvature occurred earlier in preadapted roots than in controls. These findings are consistent with suggestions that the root cap is not only the site of perception but also the location of the initial redistribution of effectors that ultimately leads to curvature.

  2. Evaluating Corn (Zea Mays L.) N Variability Via Remote Sensed Data

    Science.gov (United States)

    Sullivan, D. G.; Shaw, J. N.; Mask, P. L.; Rickman, D.; Luvall, J.; Wersinger, J. M.

    2003-01-01

    Transformations and losses of nitrogen (N) throughout the growing season can be costly. Methods in place to improve N management and facilitate split N applications during the growing season can be time consuming and logistically difficult. Remote sensing (RS) may be a method to rapidly assess temporal changes in crop N status and promote more efficient N management. This study was designed to evaluate the ability of three different RS platforms to predict N variability in corn (Zea mays L.) leaves during vegetative and early reproductive growth stages. Plots (15 x 15m) were established in the Coastal Plain (CP) and Appalachian Plateau (AP) physiographic regions each spring from 2000 to 2002 in a completely randomized design. Treatments consisted of four N rates (0, 56, 112, and 168 kg N/ha) applied as ammonium nitrate (NH4N03) replicated four time. Spectral measurements were acquired via spectroradiometer (lambda = 350 - 1050 nm), Airborne Terrestrial Applications Sensor (ATLAS) (lambda = 400 - 12,500 nm), and the IKONOS satellite (lambda = 450 - 900 nm). Spectroradiometer data were collected on a biweekly basis from V4 through R1. Due to the nature of - satellite and aircraft acquisitions, these data were acquired per availability. Chlorophyll meter (SPAD) and tissue N were collected as ancillary data along with each RS acquisition. Results showed vegetation indices derived from hand-held spectroradiometer measurements as early as V6-V8 were linearly related to yield and tissue N content. ATLAS data was correlated with tissue N at the AP site during the V6 stage (r2 = 0.66), but no significant relationships were observed at the CP site. No significant relationships were observed between plant N and IKONOS imagery. Using a combination of the greenness vegetation index (GNDVI) and the normalized difference vegetation index (NDVI), RS data acquired via ATLAS and the spectroradiometer could be used to evaluate tissue N variability and estimate corn yield variability

  3. The influence of calcium and pH on growth in primary roots of Zea mays

    Science.gov (United States)

    Hasenstein, K. H.; Evans, M. L.

    1988-01-01

    We investigated the interaction of Ca2+ and pH on root elongation in Zea mays L. cv. B73 x Missouri 17 and cv. Merit. Seedlings were raised to contain high levels of Ca2+ (HC, imbibed and raised in 10 mM CaCl2) or low levels of Ca2+ (LC, imbibed and raised in distilled water). In HC roots, lowering the pH (5 mM MES/Tris) from 6.5 to 4.5 resulted in strong, long-lasting growth promotion. Surprisingly, increasing the pH from 6.5 to 8.5 also resulted in strong growth promotion. In LC roots acidification of the medium (pH 6.5 to 4.5) resulted in transient growth stimulation followed by a gradual decline in the growth rate toward zero. Exposure of LC roots to high pH (pH shift from 6.5 to 8.5) also promoted growth. Addition of EGTA resulted in strong growth promotion in both LC and HC roots. The ability of EGTA to stimulate growth appeared not to be related to H+ release from EGTA upon Ca2+ chelation since, 1) LC roots showed a strong and prolonged response to EGTA, but only a transient response to acid pH, and 2) promotion of growth by EGTA was observed in strongly buffered solutions. We also examined the pH dependence of the release of 45Ca2+ from roots of 3-day-old seedlings grown from grains imbibed in 45Ca2+. Release of 45Ca2+ from the root into agar blocks placed on the root surface was greater the more acidic the pH of the blocks. The results indicate that Ca2+ may be necessary for the acid growth response in roots.

  4. Proliferation of maize (Zea mays L.) roots in response to localized supply of nitrate

    Science.gov (United States)

    Granato, T. C.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

    1989-01-01

    Maize (Zea mays L.) plants with two primary nodal root axes were grown for 8 d in flowing nutrient culture with each axis independently supplied with NO3-. Dry matter accumulation by roots was similar whether 1.0 mol m-3 NO3- was supplied to one or both axes. When NO3- was supplied to only one axis, however, accumulation of dry matter within the root system was significantly greater in the axis supplied with NO3-. The increased dry matter accumulation by the +N-treated axis was attributable entirely to increased density and growth of lateral branches and not to a difference in growth of the primary axis. Proliferation of lateral branches for the +N axis was associated with the capacity for in situ reduction and utilization of a portion of the absorbed NO3-, especially in the apical region where lateral primordia are initiated. Although reduced nitrogen was translocated to the -N axis, concentrations in the -N axis remained significantly lower than in the +N axis. The concentration of reduced nitrogen, as well as in vitro NO3- reductase activity, was greater in apical than in more basal regions of the +N axis. The enhanced proliferation of lateral branches in the +N axis was accompanied by an increase in total respiration rate of the axis. Part of the increased respiration was attributable to increased mass of roots. The specific respiration rate (micromoles CO2 evolved per hour per gram root dry weight) was also greater for the +N than for the -N axis. If respiration rate is taken as representative of sink demand, stimulation of initiation and growth of laterals by in situ utilization of a localized exogenous supply of NO3- establishes an increased sink demand through enhanced metabolic activity and the increased partitioning of assimilates to the +N axis responds to the difference in sink demand between +N and -N axes.

  5. Genetic and cellular analysis of cross-incompatibility in Zea mays.

    Science.gov (United States)

    Lu, Yongxian; Kermicle, Jerry L; Evans, Matthew M S

    2014-03-01

    Three genetic systems conferring cross-incompatibility have been described in Zea mays: Teosinte crossing barrier1-strong (Tcb1-s) found in teosinte, and Gametophyte factor1-strong (Ga1-s) and Ga2-s found in maize and teosinte. The reproductive barrier between maize and some weedy teosintes is controlled by the Tcb1-s locus. Multi-generation inheritance experiments on two independent Tcb1-s lineages show that the Tcb1-s barrier is unstable in some maize lines. Reciprocal crosses between Tcb1-s tester plants and three recombinants in the Tcb1-s mapping region demonstrate that the Tcb1-s haplotype contains separable male and female components. In vivo assays of the dynamics of pollen tube growth and pollen tube morphology during rejection of incompatible pollen in silks carrying the Tcb1-s, Ga1-s, or Ga2-s barriers showed that, in all three, pollen tube growth is slower than in compatible crosses at early stages and had ceased by 24 h after pollination. In all three crossing barrier systems, incompatible pollen tubes have clustered callose plugs in contrast to pollen tubes of compatible crosses. Incompatible pollen tubes growing in the Tcb1-s, Ga1-s, and Ga2-s silks have different morphologies: straight, curved, and kinked, respectively. The distinct morphologies suggest that these crossing barriers block incompatible pollen through different mechanisms. This study lays the foundation for cloning the Tcb1 genes and provides clues about the cellular mechanisms involved in pollen rejection in the Tcb1-s, Ga1-s, and Ga2-s crossing barriers.

  6. Effect of selenite and selenate on plant uptake of cadmium by maize (zea mays)

    Energy Technology Data Exchange (ETDEWEB)

    Shanker, K.; Mishra, S.; Srivastava, S. [Dayalbagh Educational Institute (India)

    1996-03-01

    Selenium has been reported to confer tolerance to toxicity of heavy metals including cadmium, a highly toxic and non essential heavy metal, which enters the food chain via plant uptake from soils. Selenium reduces availability of cadmium to plants along with other aspects of its toxicokinetics. When plants are supplied with selenite, selenium concentrations in the xylem exudate are lower than selenate. Most of the selenate was transported as selenate and unidentified organic Se compounds. In contrast, Se distribution among various Se fractions within plants does not depend significantly on whether selenite or selenate was used. Selenium has a strong tendency to form complexes with heavy metals like Cd, Hg, Ag and Tl. It has been suggested that the protective effects of selenium are due to the formation of non toxic Se-metal complexes, although the mechanism by which this protective effect is exerted remains unclear. Studies on the effect of selenium (selenite) and cadmium additions to the soil on their concentrations in lettuce and wheat has indicated the role of selenite in reduction of cadmium uptake. The cletoxifying effect of sodium selenite on cadmium ion in the freshwater fish Potyacuthus cupanus has been reported. The discovery that an element like selenium counteracts the toxicity, chemical carcinogenesis and reduces the plant uptake of other toxic metals, highlights the possibility of existence of a Se-metal interaction mechanism in soil plant systems. The uptake and translocation of root-absorbed chromium supplied through irrigation in the trivalent and hexavalant states in various parts of the onion plant (Allium cepa) grown in soil and sand culture has been recently reported by us. In continuation of that, this preliminary report describes the effect of selenite and selenate pretreatment on the uptake of cadmium in the maize plant (Zea mays).

  7. Effects of Cadmium on Polar Lipid Composition and Unsaturation in Maize (Zea mays) in Hydroponic Culture

    Institute of Scientific and Technical Information of China (English)

    Radhouane Chaffai; Tinni Nouhou Seybou; Brahim Marzouk; Ezzedine El Ferjani

    2007-01-01

    This study aimed to evaluate the effect of Cd exposure (100 μmol/L) on polar lipid composition, and to examine the level of fatty acid unsaturation in maize (Zea mays L.).In roots, the level of 16:0 and monounsaturated fatty acids (16:1+18:1)decreased in phosphatidylcholine (PC) and phosphatidylethanolamine (PE).In contrast, the proportion of unsaturated 18-C fatty acid species showed an opposite response to Cd.The content, on the other hand, of PC, PE, digalactosyldiacylglycerol (DGDG), and steryl lipids increased in roots (2.9-, 1.6-, 5.3-, and 1.7-fold increase, respectively).These results suggest that a more unsaturated fatty acid composition than found in control plants with a concomitant increase in polar lipids may favor seedling growth during Cd exposure.However, the observed increase in the steryl lipid (SL) : phospholipid (PL) ratio (twofold), the decrease in monogalactosyldiacylglycerol (MGDG) : DGDG ratio, as well as the induction of lipid peroxidation in roots may represent symptoms of membrane injury.In shoots, the unsaturation level was markedly decreased in PC and phosphatidylglycerol (PG) after Cd exposure, but showed a significant increase in sulfoquinovosyldiacylglycerol (SQDG),MGDG and DGDG.The content of PG and MGDG was decreased by about 65%, while PC accumulated to higher levels (4.4-fold increase).Taken together, these changes in the polar lipid unsaturation and composition are likely to be due to alterations in the glycerolipid pathway.These results also support the idea that the increase in overall unsaturation plays some role in enabling the plant to withstand the metal exposure.

  8. Zea mays iRS1563: a comprehensive genome-scale metabolic reconstruction of maize metabolism.

    Directory of Open Access Journals (Sweden)

    Rajib Saha

    Full Text Available The scope and breadth of genome-scale metabolic reconstructions have continued to expand over the last decade. Herein, we introduce a genome-scale model for a plant with direct applications to food and bioenergy production (i.e., maize. Maize annotation is still underway, which introduces significant challenges in the association of metabolic functions to genes. The developed model is designed to meet rigorous standards on gene-protein-reaction (GPR associations, elementally and charged balanced reactions and a biomass reaction abstracting the relative contribution of all biomass constituents. The metabolic network contains 1,563 genes and 1,825 metabolites involved in 1,985 reactions from primary and secondary maize metabolism. For approximately 42% of the reactions direct literature evidence for the participation of the reaction in maize was found. As many as 445 reactions and 369 metabolites are unique to the maize model compared to the AraGEM model for A. thaliana. 674 metabolites and 893 reactions are present in Zea mays iRS1563 that are not accounted for in maize C4GEM. All reactions are elementally and charged balanced and localized into six different compartments (i.e., cytoplasm, mitochondrion, plastid, peroxisome, vacuole and extracellular. GPR associations are also established based on the functional annotation information and homology prediction accounting for monofunctional, multifunctional and multimeric proteins, isozymes and protein complexes. We describe results from performing flux balance analysis under different physiological conditions, (i.e., photosynthesis, photorespiration and respiration of a C4 plant and also explore model predictions against experimental observations for two naturally occurring mutants (i.e., bm1 and bm3. The developed model corresponds to the largest and more complete to-date effort at cataloguing metabolism for a plant species.

  9. Soluble and bound phenolic compounds in different Bolivian purple corn ( Zea mays L.) cultivars.

    Science.gov (United States)

    Cuevas Montilla, Elyana; Hillebrand, Silke; Antezana, Amalia; Winterhalter, Peter

    2011-07-13

    In nine Bolivian purple corn ( Zea mays L.) varieties the content of phenolic compounds as well as the anthocyanin composition has been determined. The phenotypes under investigation included four red and five blue varieties (Kulli, Ayzuma, Paru, Tuimuru, Oke, Huaca Songo, Colorado, Huillcaparu, and Checchi). In purple corn, phenolic compounds were highly concentrated in cell walls. Thus, simultaneous determination of soluble and bound-form phenolics is essential for analysis, extraction, and quantification. The present study reports the determination of soluble and insoluble-bound fraction of phenolic compounds by HPLC-DAD and HPLC-ESI-MS(n) in Bolivian purple corn varieties. Enzymatic, thermal, and alkaline hydrolyses were used to obtain the cell wall-linked phenolic compounds. Ferulic acid values ranged from 132.9 to 298.4 mg/100 g, and p-coumaric acid contents varied between 251.8 and 607.5 mg/100 g dry weight (DW), respectively, and were identified as the main nonanthocyanin phenolics. The total content of phenolic compounds ranged from 311.0 to 817.6 mg gallic acid equivalents (GAE)/100 g DW, and the percentage contribution of bound to total phenolics varied from 62.1 to 86.6%. The total monomeric anthocyanin content ranged from 1.9 to 71.7 mg cyanidin-3-glucoside equivalents/100 g DW. Anthocyanin profiles are almost the same among the different samples. Differences are observed only in the relative percentage of each anthocyanin. Cyanidin-3-glucoside and its malonated derivative were detected as major anthocyanins. Several dimalonylated monoglucosides of cyanidin, peonidin, and pelargonidin were present as minor constituents.

  10. Kinetics of sup 15 NH sub 4 sup + assimilation in Zea mays

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, J.R.; Ju, G.C.; Rich, P.J.; Rhodes, D. (EMBRAPA-Centro Nacional de Pesquisa de Hortalicas-CNPH, Brasilia-D.F. (Brazil) Purdue Univ., West Lafayette, IN (USA))

    1990-10-01

    Comparative studies of {sup 15}NH{sub 4}{sup +} assimilation were undertaken with a GDH1-null mutant of Zea mays and a related (but not strictly isogenic) GDH1-positive wild type from which this mutant was derived. The kinetics of {sup 15}NH{sub 4}{sup +} assimilation into free amino acids and total reduced nitrogen were monitored in both roots and shoots of 2-week-old seedlings supplied with 5 millimolar 99% ({sup 15}NH{sub 4}){sub 2}SO{sub 4} via the aerated root medium in hydroponic culture over a 24-h period. The GDH1-null mutant, with a 10- to 15-fold lower total root GDH activity in comparison to the wild type, was found to exhibit a 40 to 50% lower rate of {sup 15}NH{sub 4}{sup +} assimilation into total reduced nitrogen. The lower rates of {sup 15}NH{sub 4}{sup +} assimilation in the mutant was associated with lower rates of labeling of several free amino acids (including glutamate, glutamine-amino N, aspartate, asparagine-amino N, and alanine) in both roots and shoots of the mutant in comparison to the wild type. Qualitatively, these labeling kinetics appear consistent with a reduced flux of {sup 15}N via glutamate in the GDH1-null mutant. However, the responses of the two genotypes to the potent inhibitor of glutamine synthetase, methionine sulfoximine, and differences in morphology of the two genotypes (particularly a lower shoot:root ratio in the GDH1-null mutant) urge caution in concluding that GDH1 is solely responsible for these differences in ammonia assimilation rate.

  11. Pengaruh Jarak Tanam dan Pemangkasan terhadap Kualitas Silase Dua Varietas Jagung (Zea mays L.

    Directory of Open Access Journals (Sweden)

    La Karimuna

    2009-04-01

    Full Text Available Effects of crop arrangement and cutting on the silages quality of two varieties of maize (Zea mays L. ABSTRACT. The objective of this experiment was to study the interaction effect of varieties, spacing and cutting on the quality of silage as foodstuff. The experiment had been conducted from January to April, 2007 at the experimental Garden of Faculty of Agriculture, University of Haluoleo. This experiment was arranged in Split-Split plot design with three factors. The first factor was variety as main plot, consisting of BISI-2 variety and local variety; the second factor was space arrangement as sub plot, consisting of 60 cm x 40 cm (J1, 75 cm x 40 cm (J2, 90 cm x 40 cm (J3, the third factor was cutting period as sub plot, consisting of no cutting (Po, cutting on 40 days (P1, and cutting on 55 days (P2. So that there were 2 x 3 x 3 x 3 = 54 experimental units. Analysis of variance was applied to know the effect of treatment. If so, least significant difference (LSD 0.05 (95 % confidence level was used. Variables observed was plant growth determining silages quality, consisting of quality of crude protein, crude fiber, crude fat, and water. Results of research revealed that interaction affect of spacing and cutting periods on 40 days of BISI-2 variety gave the best yield of plant growth for plant height. While the local variety tended to adverse effect of cutting. However, the quality of silages of two varieties tended to be similar. Every crop spacing had a positive effect of cutting on 40 days. The best quality of silages of two varieties was resulted from the interaction between spacing 75 cm x 40 cm and cutting of 40 days.

  12. Expression and characterization of plasma membrane aquaporins in stomatal complexes of Zea mays.

    Science.gov (United States)

    Heinen, Robert B; Bienert, Gerd Patrick; Cohen, David; Chevalier, Adrien S; Uehlein, Norbert; Hachez, Charles; Kaldenhoff, Ralf; Le Thiec, Didier; Chaumont, François

    2014-10-01

    Stomata, the microscopic pores on the surface of the aerial parts of plants, are bordered by two specialized cells, known as guard cells, which control the stomatal aperture according to endogenous and environmental signals. Like most movements occurring in plants, the opening and closing of stomata are based on hydraulic forces. During opening, the activation of plasma membrane and tonoplast transporters results in solute accumulation in the guard cells. To re-establish the perturbed osmotic equilibrium, water follows the solutes into the cells, leading to their swelling. Numerous studies have contributed to the understanding of the mechanism and regulation of stomatal movements. However, despite the importance of transmembrane water flow during this process, only a few studies have provided evidence for the involvement of water channels, called aquaporins. Here, we microdissected Zea mays stomatal complexes and showed that members of the aquaporin plasma membrane intrinsic protein (PIP) subfamily are expressed in these complexes and that their mRNA expression generally follows a diurnal pattern. The substrate specificity of two of the expressed ZmPIPs, ZmPIP1;5 and ZmPIP1;6, was investigated by heterologous expression in Xenopus oocytes and yeast cells. Our data show that both isoforms facilitate transmembrane water diffusion in the presence of the ZmPIP2;1 isoform. In addition, both display CO2 permeability comparable to that of the CO2 diffusion facilitator NtAQP1. These data indicate that ZmPIPs may have various physiological roles in stomatal complexes.

  13. Towards efficient photosynthesis: overexpression of Zea mays phosphoenolpyruvate carboxylase in Arabidopsis thaliana.

    Science.gov (United States)

    Kandoi, Deepika; Mohanty, Sasmita; Govindjee; Tripathy, Baishnab C

    2016-12-01

    Plants with C4 photosynthesis are efficient in carbon assimilation and have an advantage over C3 photosynthesis. In C4 photosynthesis, the primary CO2 fixation is catalyzed by phosphoenolpyruvate carboxylase (PEPC). Here, we show that overexpression of Zea mays PEPC cDNA, under the control of (35)S promoter, in Arabidopsis thaliana resulted in ~7-10 fold higher protein abundance and ~7-10 fold increase in PEPC activity in the transgenic lines than that in the vector control. We suggest that overexpression of PEPC played an anaplerotic role to increase the supply of 4-carbon carboxylic acids, which provided carbon skeletons for increased amino acid and protein synthesis. Higher protein content must have been responsible for increased metabolic processes including chlorophyll biosynthesis, photosynthesis, and respiration. Consequently, the PEPC-overexpressed transgenic plants had higher chlorophyll content, enhanced electron transport rate (ETR), lower non-photochemical quenching (NPQ) of chlorophyll a fluorescence, and a higher performance index (PI) than the vector control. Consistent with these observations, the rate of CO2 assimilation, the starch content, and the dry weight of PEPC-overexpressed plants increased by 14-18 %, 10-18 %, and 6.5-16 %, respectively. Significantly, transgenics were tolerant to salt stress as they had increased ability to synthesize amino acids, including the osmolyte proline. NaCl (150 mM)-treated transgenic plants had higher variable to maximum Chl a fluorescence (F v/F m) ratio, higher PI, higher ETR, and lower NPQ than the salt-treated vector controls. These results suggest that expression of C4 photosynthesis enzyme(s) in a C3 plant can improve its photosynthetic capacity with enhanced tolerance to salinity stress.

  14. Modulation of thiamine metabolism in Zea mays seedlings under conditions of abiotic stress.

    Science.gov (United States)

    Rapala-Kozik, Maria; Kowalska, Ewa; Ostrowska, Katarzyna

    2008-01-01

    The responses of plants to abiotic stress involve the up-regulation of numerous metabolic pathways, including several major routes that engage thiamine diphosphate (TDP)-dependent enzymes. This suggests that the metabolism of thiamine (vitamin B1) and its phosphate esters in plants may be modulated under various stress conditions. In the present study, Zea mays seedlings were used as a model system to analyse for any relation between the plant response to abiotic stress and the properties of thiamine biosynthesis and activation. Conditions of drought, high salt, and oxidative stress were induced by polyethylene glycol, sodium chloride, and hydrogen peroxide, respectively. The expected increases in the abscisic acid levels and in the activities of antioxidant enzymes including catalase, ascorbate peroxidase, and glutathione reductase were found under each stress condition. The total thiamine compound content in the maize seedling leaves increased under each stress condition applied, with the strongest effects on these levels observed under the oxidative stress treatment. This increase was also found to be associated with changes in the relative distribution of free thiamine, thiamine monophosphate (TMP), and TDP. Surprisingly, the activity of the thiamine synthesizing enzyme, TMP synthase, responded poorly to abiotic stress, in contrast to the significant enhancement found for the activities of the TDP synthesizing enzyme, thiamine pyrophosphokinase, and a number of the TDP/TMP phosphatases. Finally, a moderate increase in the activity of transketolase, one of the major TDP-dependent enzymes, was detectable under conditions of salt and oxidative stress. These findings suggest a role of thiamine metabolism in the plant response to environmental stress.

  15. Characterization and Transposon Mutagenesis of the Maize (Zea mays) Pho1 Gene Family

    Science.gov (United States)

    Salazar-Vidal, M. Nancy; Acosta-Segovia, Edith; Sánchez-León, Nidia; Ahern, Kevin R.; Brutnell, Thomas P.; Sawers, Ruairidh J. H.

    2016-01-01

    Phosphorus is an essential nutrient for all plants, but also one of the least mobile, and consequently least available, in the soil. Plants have evolved a series of molecular, metabolic and developmental adaptations to increase the acquisition of phosphorus and to maximize the efficiency of use within the plant. In Arabidopsis (Arabidopsis thaliana), the AtPHO1 protein regulates and facilitates the distribution of phosphorus. To investigate the role of PHO1 proteins in maize (Zea mays), the B73 reference genome was searched for homologous sequences, and four genes identified that were designated ZmPho1;1, ZmPho1;2a, ZmPho1;2b and ZmPho1;3. ZmPho1;2a and ZmPho1;2b are the most similar to AtPHO1, and represent candidate co-orthologs that we hypothesize to have been retained following whole genome duplication. Evidence was obtained for the production of natural anti-sense transcripts associated with both ZmPho1;2a and ZmPho1;2b, suggesting the possibility of regulatory crosstalk between paralogs. To characterize functional divergence between ZmPho1;2a and ZmPho1;2b, a program of transposon mutagenesis was initiated using the Ac/Ds system, and, here, we report the generation of novel alleles of ZmPho1;2a and ZmPho1;2b. PMID:27648940

  16. Determination of Genetic Coefficients of Some Maize (Zea mays L.) Cultivars of Iran for Application in Crop Simulation Models

    OpenAIRE

    S Rahimi Moghaddam; R. Deihimfard; S Soufizadeh; J Kambouzia; F Nazariyan Firuzabadi; H Eyni Nargeseh

    2015-01-01

    A field experiment was conducted at the research field of the University of Lorestan in 2011 as a randomized complete block design with three replications to estimate genetic coefficients of some maize (Zea mays L.) cultivars. Treatments include six maize cultivars (T.V.C.767 and S.C.704 from late maturing group, T N.S640 and Maxima from mid-maturing group, and Koppany and D.C.370 from early maturing group). Results showed that there were significant differences among cultivars in terms of st...

  17. Evaluating the physiological state of maize (Zea mays L.) plants by direct-injection electrospray mass spectrometry (DIESI-MS).

    Science.gov (United States)

    García-Flores, Martín; Juárez-Colunga, Sheila; Montero-Vargas, Josaphat Miguel; López-Arciniega, Janet Ana Isabel; Chagolla, Alicia; Tiessen, Axel; Winkler, Robert

    2012-06-01

    Climatic change is an increasing challenge for agriculture that is driving the development of suitable crops in order to ensure supply for both human nutrition and animal feed. In this context, it is increasingly important to understand the biochemical responses of cells to environmental cues at the whole system level, an aim that is being brought closer by advances in high throughput, cost-efficient plant metabolomics. To support molecular breeding activities, we have assessed the economic, technical and statistical feasibility of using direct mass spectrometry methods to evaluate the physiological state of maize (Zea mays L.) plants grown under different stress conditions.

  18. Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by an enzyme preparation from Zea mays

    Science.gov (United States)

    Reinecke, D. M.; Bandurski, R. S.

    1988-01-01

    Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.

  19. Efeitos da densidade e proporção de plantas de milho (Zea mays L. e caruru (Amaranhus retroflexus L. em competição Density and porportion effects among corn (Zea mays L. and pigweed (Amaranthus retroflexus L. under competition

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    Pedro J. Christoffoleti

    1996-01-01

    Full Text Available A maioria dos estudos de competição, entre plantas daninhas e cultivadas, conduzidos nos últimos anos, procuram quantificar a interferência que as plantas daninhas causam sobre as culturas; no entanto, poucos destes trabalhos estudam mecanisticamente os efeitos da densidade e da proporção de plantas em uma mistura de espécies, a importância da competição intra e interespecífica e a diferenciação de nicho ecológico. Desta forma, foi desenvolvida a presente pesquisa com o objetivo principal de descrever as interações competitivas e os índices de competitividade entre plantas de milho (Zea mays L. e caruru (Amarathus retroflexus L.. A metodologia utilizada foi a de um experimento substitutivo com densidade total de 400 plantas/m2 e 5 proporções, além da monocultura que variou de 50 a 800 plantas/m2, sendo conduzido no delineamento experimental de blocos casualizados, com quatro repetições. Os resultados obtidos foram analisados pelo método convencional de análise de experimentos substitutivos e pelo método da produção recíproca total e por planta. O milho foi um competidor muito mais agressivo que o caruru, sendo que para a planta cultivada a competição intraespecífica é mais importante que a competição interespecífica. O contrário é verdadeiro para o caruru, ou seja, a competição interespecífica é mais importante que a intraespecífica. Ambas espécies de plantas estão competindo pelos mesmos fatores de crescimento, pois o índice que mede a diferenciação de nicho ecológico é menor que 1,0. A determinação da influência da densidade e proporção de espécies em estudos de competição entre plantas é muito importante para a compreensão das interações competitivas.Most of the competition studies between weeds and crops conducted lately quantify the interference that the weeds cause to crops; however, these researches do not show mechanistically neither the effects of density and proportion of

  20. La aplicación de abono organo-mineral: una alternativa para la producción de maíz (Zea mays L., en suelos pardos con carbonatos.

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    Ignacio Corrales Garriga

    2013-04-01

    Full Text Available RESUMEN Durante tres años se condujo un experimento en áreas del Instituto de Investigaciones de Viandas Tropicales (INIVIT de Camagüey, empleando diferentes abonos organo-mineral, con el objetivo de conocer su influencia en el rendimiento del maíz (Zea maiz, L, sobre un suelo Pardo Sialítico Mullido Carbonatado de pH ligeramente ácido, bajo contenido de P2O5 y medio de K2O y materia orgánica. Para las mezclas organo-mineral se emplearon como abonos orgánicos el estiércol vacuno y la cachaza y como fertilizantes minerales, el superfosfato triple y el cloruro de potasio. El organo-mineral se aplicó en el momento de la siembra a una dosis de 745 kg ha1 de acuerdo a cada tratamiento, los que fueron replicados 4 veces en un diseño de bloques al azar. Se midió el rendimiento y sus componentes y se tomaron muestras de suelo para conocer la variación de sus propiedades. Los datos fueron evaluados por un análisis de varianza de clasificación doble y se aplicó la prueba de rango múltiple de Duncan para un nivel de significación del 5 %. Los resultados muestran que el empleo de los abonos organo-minerales favorece el rendimiento, reducen los fertilizantes químicos a emplear y mejoran las propiedades del suelo. ORGANO-MINERAL FERTILIZER APPLICATION: AN ALTERNATIVE FOR PRODUCTION OF CORN (Zea mays L., IN SIALYTIC BROWN CARBONATED SOIL. ABSTRACT. For three years, an experiment was conducted in areas of the Research Institute (INIVIT Camaguey , using different organo- mineral fertilizers , in order to study its influence on the performance of maize ( Zea mays , L on a Fluffy Sialytic Brown Carbonated soil slightly acidic pH , low P2O5 and K2O and medium organic matter. For organo- mineral mixtures were used as organic fertilizers and cow manure and cachaza and mineral fertilizer, triple superphosphate and potassium chloride. The organo- mineral was applied at the time of planting at a dose of 745 kg ha1 according to each treatment, which

  1. Breve informe sobre la coca

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    Lauro Hinostroza García

    1985-12-01

    Full Text Available El presente informe se integra en la investigación dirigida por el doctor Juan Ossio, por encargo de la Organización de los Estados Americanos (O.E.A. sobre “EFECTOS SOCIALES, CULTURALES, MÉDICOS Y ECONÓMICOS DEL USO TRADICIONAL DE LA COCA EN POBLACIONES DEL ANTIPLANO Y SIERRA DEL PERÚ, EN ESPECIAL DE LAS POBLACIONES INDÍGENAS”. Expone tópicos sobre la hoja de coca en la cultura andina: criterios clasificatorios, mitos, canciones y una muestra de qatipay o seguimiento. Este último es una práctica ritual importante para el campesinado andino, orienta el presente, pasado y futuro de toda su actividad. Cada hoja, por su forma, posición y tamaño, develará los roles sociales que ha de asumir, es decir los misterios del tiempo.

  2. Sobre la verdad en periodismo

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    Julio Estremadoyro Alegre

    2011-05-01

    Full Text Available Cuando un periodista informa sobre un desastre natural, con granpérdida de vidas, las autoridades y las fuentes de primera manodan cifras que son difundidas como verdades del suceso. Sinembargo, y la experiencia lo confirma, al día siguiente la cifraspueden haber cambiado y, por lo tanto, la verdad informativa esotra. Y así, sucesivamente, cada día habrá novedades y nuevas cifras verdaderas.

  3. Enhanced formation of aerenchyma and induction of a barrier to radial oxygen loss in adventitious roots of Zea nicaraguensis contribute to its waterlogging tolerance as compared with maize (Zea mays ssp. mays).

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    Abiko, Tomomi; Kotula, Lukasz; Shiono, Katsuhiro; Malik, Al Imran; Colmer, Timothy David; Nakazono, Mikio

    2012-09-01

    Enhancement of oxygen transport from shoot to root tip by the formation of aerenchyma and also a barrier to radial oxygen loss (ROL) in roots is common in waterlogging-tolerant plants. Zea nicaraguensis (teosinte), a wild relative of maize (Zea mays ssp. mays), grows in waterlogged soils. We investigated the formation of aerenchyma and ROL barrier induction in roots of Z. nicaraguensis, in comparison with roots of maize (inbred line Mi29), in a pot soil system and in hydroponics. Furthermore, depositions of suberin in the exodermis/hypodermis and lignin in the epidermis of adventitious roots of Z. nicaraguensis and maize grown in aerated or stagnant deoxygenated nutrient solution were studied. Growth of maize was more adversely affected by low oxygen in the root zone (waterlogged soil or stagnant deoxygenated nutrient solution) compared with Z. nicaraguensis. In stagnant deoxygenated solution, Z. nicaraguensis was superior to maize in transporting oxygen from shoot base to root tip due to formation of larger aerenchyma and a stronger barrier to ROL in adventitious roots. The relationships between the ROL barrier formation and suberin and lignin depositions in roots are discussed. The ROL barrier, in addition to aerenchyma, would contribute to the waterlogging tolerance of Z. nicaraguensis.

  4. Effect of Nitrogen Nutritional Stress on some Mineral Nutrients and Photosynthetic Apparatus of Zea mays L. and Vigna unguiculata L.

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    Akinbode Foluso OLOGUNDUDU

    2013-08-01

    Full Text Available The study investigated the responses of maize (Zea mays L. and cowpea (Vigna unguiculata L. Walp. seedlings metabolic activities and photosynthetic apparatus to nitrogen nutritional stress. Germination of seeds was done using treated sand in sixty plastic pots and the seedlings were divided into four nutrient regimes. A group of the seedlings was nutrient stressed by administering 200 ml of complete nutrient solution minus nitrogen (-N while the other groups were fed with five times (X5N and ten times (X10N the optimal concentration of nitrogen and the last regime was fed with full nutrient solution (FN. The photosynthetic parameters studied included chlorophylls ‘a’ and ‘b’ respectively; carotenes and xanthophyll while the mineral elements investigated include potassium, calcium and magnesium. The result of the growth analysis showed that nitrogen deficiency promotes an increase in the content of abscisic acid (ABA, causing stomatal closure and a reduction in photosynthesis. This explains the higher rate of leaf abscission in -N plants. A comparison of calcium ion and magnesium ion concentrations in both optimal and stressed conditions reveals that the two ions show antagonism in uptake. There is a correlation between nitrogen and magnesium accumulation as magnesium ion plays a vital role in chlorophyll biosynthesis, protein synthesis and photosynthesis. The pattern of accumulation of photosynthetic apparatus in both maize and cowpea follow a similar pattern. Chlorophyll a dictated the growth pattern of other photosynthetic apparatus in both Zea mays and Vigna unguiculata.

  5. Presence of Zea luxurians (Durieu and Ascherson) Bird in Southern Brazil: Implications for the Conservation of Wild Relatives of Maize

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    2015-01-01

    Records of the occurrence of wild relatives of maize in South American lowlands are unprecedented, especially in sympatric coexistence with landraces. This fact is relevant, because regions of occurrence of wild relatives of cultivated plants should be a priority for conservation, even if they do not correspond to the center of origin of the species. The aim of this study was to identify and characterize the wild relatives of maize in the Far West of Santa Catarina, southern Brazil. Therefore, phenotypic characterization was performed for five populations, based on 22 morphological traits deemed as fundamental for classifying the species of the genus Zea, and validated through the characterization of chromosomal knobs of two populations. The occurrence and distribution of teosinte populations were described through semi-structured interviews applied to a sample of 305 farmers. A total of 136 teosinte populations were identified; 75% of them occur spontaneously, 17% are cultivated populations, and 8% occur both ways, for the same farm. Populations that were characterized morphologically had trapezoidal fruits mostly, upright tassel branch (4–18), non-prominent main branch and glabrous glumes, with two protruding outer ribs and 8 inner ribs, on average. Cytogenetic analysis identified 10 pairs of homologous chromosomes (2n = 20) with 26 knobs, located in the terminal region of all chromosomes. The similarity of these results with the information reported in the literature indicates that the five populations of wild relatives of maize in this region of Santa Catarina belong to the botanical species Zea luxurians. PMID:26488577

  6. A morphometric analysis of the redistribution of organelles in columella cells of horizontally-oriented roots of Zea mays

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    Moore, R.

    1986-01-01

    In order to determine what structural changes in graviperceptive cells are associated with onset of root gravicurvature, the redistribution of organelles in columella cells of horizontally-oriented, graviresponding roots of Zea mays has been quantified. Root gravicurvature began by 15 min after reorientation, and did not involve significant changes in the (i) volume of individual columella cells or amyloplasts, (ii) relative volume of any cellular organelle, (iii) number of amyloplasts per columella cell, or (iv) surface area of cellular location of endoplasmic reticulum. Sedimentation of amyloplasts began within 1 to 2 min after reorientation, and was characterized by an intensely staining area of cytoplasm adjacent to the sedimenting amyloplasts. By 5 min after reorientation, amyloplasts were located in the lower distal corner of columella cells, and, by 15 min after reorientation, overlaid the entire length of the lower cell wall. No consistent contact between amyloplasts and any cellular structure was detected at any stage of gravicurvature. Centrally-located nuclei initially migrated upward in columella cells of horizontally-oriented roots, after which they moved to the proximal ends of the cells by 15 min after reorientation. No significant pattern of redistribution of vacuoles, mitochondria, dictyosomes, or hyaloplasm was detected that correlated with the onset of gravicurvature. These results indicate that amyloplasts and nuclei are the only organelles whose movements correlate positively with the onset of gravicurvature by primary roots of this cultivar of Zea mays.

  7. ZmSOC1, a MADS-box transcription factor from Zea mays, promotes flowering in Arabidopsis.

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    Zhao, Suzhou; Luo, Yanzhong; Zhang, Zhanlu; Xu, Miaoyun; Wang, Weibu; Zhao, Yangmin; Zhang, Lan; Fan, Yunliu; Wang, Lei

    2014-11-03

    Zea mays is an economically important crop, but its molecular mechanism of flowering remains largely uncharacterized. The gene, SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1), integrates multiple flowering signals to regulate floral transition in Arabidopsis. In this study, ZmSOC1 was isolated from Zea mays. Sequence alignment and phylogenetic analysis demonstrated that the ZmSOC1 protein contained a highly conserved MADS domain and a typical SOC1 motif. ZmSOC1 protein was localized in the nucleus in protoplasts and showed no transcriptional activation activity in yeast cells. ZmSOC1 was highly expressed in maize reproductive organs, including filaments, ear and endosperm, but expression was very low in embryos; on the other hand, the abiotic stresses could repress ZmSOC1 expression. Overexpression of ZmSOC1 resulted in early flowering in Arabidopsis through increasing the expression of AtLFY and AtAP1. Overall, these results suggest that ZmSOC1 is a flowering promoter in Arabidopsis.

  8. Measurement of the rates of oxindole-3-acetic acid turnover, and indole-3-acetic acid oxidation in Zea mays seedlings

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    Nonhebel, H. M.; Bandurski, R. S. (Principal Investigator)

    1986-01-01

    Oxindole-3-acetic acid is the principal catabolite of indole-3-acetic acid in Zea mays seedlings. In this paper measurements of the turnover of oxindole-3-acetic acid are presented and used to calculate the rate of indole-3-acetic acid oxidation. [3H]Oxindole-3-acetic acid was applied to the endosperm of Zea mays seedlings and allowed to equilibrate for 24 h before the start of the experiment. The subsequent decrease in its specific activity was used to calculate the turnover rate. The average half-life of oxindole-3-acetic acid in the shoots was found to be 30 h while that in the kernels had an average half-life of 35h. Using previously published values of the pool sizes of oxindole-3-acetic acid in shoots and kernels from seedlings of the same age and variety, and grown under the same conditions, the rate of indole-3-acetic acid oxidation was calculated to be 1.1 pmol plant-1 h-1 in the shoots and 7.1 pmol plant-1 h-1 in the kernels.

  9. Intraear Compensation of Field Corn, Zea mays, from Simulated and Naturally Occurring Injury by Ear-Feeding Larvae.

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    Steckel, S; Stewart, S D

    2015-06-01

    Ear-feeding larvae, such as corn earworm, Helicoverpa zea Boddie (Lepidoptera: Noctuidae), can be important insect pests of field corn, Zea mays L., by feeding on kernels. Recently introduced, stacked Bacillus thuringiensis (Bt) traits provide improved protection from ear-feeding larvae. Thus, our objective was to evaluate how injury to kernels in the ear tip might affect yield when this injury was inflicted at the blister and milk stages. In 2010, simulated corn earworm injury reduced total kernel weight (i.e., yield) at both the blister and milk stage. In 2011, injury to ear tips at the milk stage affected total kernel weight. No differences in total kernel weight were found in 2013, regardless of when or how much injury was inflicted. Our data suggested that kernels within the same ear could compensate for injury to ear tips by increasing in size, but this increase was not always statistically significant or sufficient to overcome high levels of kernel injury. For naturally occurring injury observed on multiple corn hybrids during 2011 and 2012, our analyses showed either no or a minimal relationship between number of kernels injured by ear-feeding larvae and the total number of kernels per ear, total kernel weight, or the size of individual kernels. The results indicate that intraear compensation for kernel injury to ear tips can occur under at least some conditions.

  10. VHDL, a larval storage protein from the corn earworm, Helicoverpa zea, is a member of the vitellogenin gene family.

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    Sum, Herbert; Haunerland, Norbert H

    2007-10-01

    The hemolymph of last instar larvae of the corn earworm, Helicoverpa zea contains a blue very high-density lipoprotein (VHDL) that is selectively taken up into fat body prior to pupation. Its amino-terminal sequence was determined by Edman degradation, and used to design a degenerate primer for PCR amplification. With 5' and 3' RACE techniques, the entire cDNA coding for VHDL was amplified and sequenced. Conceptual translation reveals a 173 kDa protein that contains a 15 amino acid signal sequence immediately before the experimentally determined N-terminus of the mature protein. The protein contains a typical lipoprotein N-terminal domain, and shows high sequence similarity to vitellogenins from Lepidoptera and other insect species. VHDL mRNA was not detectable in adult H. zea, and antibodies raised against VHDL did not react with adult hemolymph or yolk proteins. Therefore VHDL, although a member of the vitellogenin gene family, seems to be distinct from the vitellogenin expressed in adult females.

  11. Effect of Nitrogen Nutritional Stress on Some Growth Parameters of Zea mays L. and Vigna unguiculata (L. Walp.

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    Akinbode Foluso OLOGUNDUDU

    2013-02-01

    Full Text Available This study investigated the responses of maize (Zea mays L. and cowpea (Vigna unguiculata L. Walp. seedlings growth parameters to nitrogen nutritional stress. This was with a view to determining whether nitrogen nutritional stress would retard or enhance maize and cowpea growth, partly, wholly or not at all through its effect on biomass accumulation and some morphological parameters. Germination of seeds was done using treated sand in sixty plastic pots. A group of the seedlings was nutrient stressed by administering 200 ml of complete nutrient solution minus nitrogen (-N while the other groups were fed with five times (X5N and ten times (X10N the optimal concentration of nitrogen and the last regime was fed with full nutrient solution (FN. The effects of optimal concentration and nitrogen stress on the growth rates (as measured by their fresh and dry weight were studied. The result of the growth analysis showed that there was increase in shoot height with supraoptimal concentrations of nitrogen treatments (X10N and X5N while there was a decrease in shoot height with minus nitrogen (-N regimes. The observed higher biomass (dry matter yield under the FN regimes in both Zea mays and Vigna unguiculata were attributed to optimal nutrient assimilation rate.

  12. Plantas de cobertura e seus efeitos sobre o feijoeiro em plantio direto

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    Oliveira Tadário Kamel de

    2002-01-01

    Full Text Available O objetivo deste trabalho foi estimar o rendimento de matéria fresca, matéria seca e o acúmulo de nutrientes da fitomassa produzida por milheto (Pennisetum americanum (L. Leek, sorgo (Sorghum bicolor (L. Moench, milho (Zea mays L., mucuna-preta (Stizolobium aterrimum e feijão-de-porco (Canavalia ensiformis (L. DC., em cultivo exclusivo e consorciado, e seus efeitos sobre o feijoeiro (Phaseolus vulgaris L. cv. Carioca em plantio direto. Os tratamentos consistiram no cultivo exclusivo das espécies e nos consórcios das gramíneas com as leguminosas. Utilizou-se o delineamento experimental em blocos casualizados, com quatro repetições. O sorgo em cultivo exclusivo apresenta maior produtividade de matéria fresca e, juntamente com o milheto exclusivo e o consórcio milheto e mucuna-preta, maior produtividade de matéria seca. Ocorre maior acúmulo de nutrientes no milheto exclusivo e consorciado com mucuna-preta. Posteriormente, realizou-se o plantio direto do feijoeiro, cujo rendimento de grãos é influenciado pelas diferentes palhadas das plantas de cobertura no sistema plantio direto, sendo mais afetado pela espécie produtora de palha do que pela sua forma de cultivo.

  13. Lipid extracted microalgal biomass residue as a fertilizer substitute for Zea mays L

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    Rahulkumar eMaurya

    2016-01-01

    Full Text Available High volumes of lipid extracted microalgal biomass residues (LMBRs are expected to be produced upon commencement of biodiesel production on a large scale, thus necessitating its value addition for sustainable development. LMBRs of Chlorella variabilis and Lyngbya majuscula were employed to substitute the nitrogen content of recommended rate of fertilizer (RRF for Zea mays L. The pot experiment comprised of 10 treatments, i.e. T1 (No fertilizer; T2 (RRF-120 N: 60 P2O5: 40 K2O kg ha-1; T3 to T6 -100, 75, 50 and 25% N through LMBR of the Chlorella sp., respectively; T7 to T10 -100, 75, 50 and 25% N through LMBR of Lyngbya sp., respectively. It was found that all LMBR substitution treatments were at par to RRF with respect to grain yield production. T10 gave the highest grain yield (65.16 g plant-1, which was closely followed by that (63.48 g plant-1 under T5. T10 also recorded the highest phosphorus and potassium contents in grains. T4 was markedly superior over control in terms of dry matter accumulation (DMA as well as carbohydrate content, which was ascribed to higher pigment content and photosynthetic activity in leaves. Even though considerably lower DMA was obtained in Lyngbya treatments, which might have been due to the presence of some toxic factors, no reduction in grain yield was apparent. The length of the tassel was significantly higher in either of the LMBRs at any substitution rates over RRF, except T6 and T7. The ascorbate peroxidase activity decreased with decreasing dose of Chlorella LMBR, while all the Lyngbya LMBR treatments recorded lower activity, which were at par with each other. Among the Chlorella treatments, only T5 recorded significantly higher values of glutathione reductase activity over RRF, while the rest were at par. There were significant increases in carbohydrate and crude fat, respectively, only in T4 and T3 over RRF, while no change was observed in crude protein due to LMBR treatments. Apparently, there was no

  14. Stable isotope biogeochemistry of seabird guano fertilization: results from growth chamber studies with maize (Zea mays.

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    Paul Szpak

    Full Text Available BACKGROUND: Stable isotope analysis is being utilized with increasing regularity to examine a wide range of issues (diet, habitat use, migration in ecology, geology, archaeology, and related disciplines. A crucial component to these studies is a thorough understanding of the range and causes of baseline isotopic variation, which is relatively poorly understood for nitrogen (δ(15N. Animal excrement is known to impact plant δ(15N values, but the effects of seabird guano have not been systematically studied from an agricultural or horticultural standpoint. METHODOLOGY/PRINCIPAL FINDINGS: This paper presents isotopic (δ(13C and δ(15N and vital data for maize (Zea mays fertilized with Peruvian seabird guano under controlled conditions. The level of (15N enrichment in fertilized plants is very large, with δ(15N values ranging between 25.5 and 44.7‰ depending on the tissue and amount of fertilizer applied; comparatively, control plant δ(15N values ranged between -0.3 and 5.7‰. Intraplant and temporal variability in δ(15N values were large, particularly for the guano-fertilized plants, which can be attributed to changes in the availability of guano-derived N over time, and the reliance of stored vs. absorbed N. Plant δ(13C values were not significantly impacted by guano fertilization. High concentrations of seabird guano inhibited maize germination and maize growth. Moreover, high levels of seabird guano greatly impacted the N metabolism of the plants, resulting in significantly higher tissue N content, particularly in the stalk. CONCLUSIONS/SIGNIFICANCE: The results presented in this study demonstrate the very large impact of seabird guano on maize δ(15N values. The use of seabird guano as a fertilizer can thus be traced using stable isotope analysis in food chemistry applications (certification of organic inputs. Furthermore, the fertilization of maize with seabird guano creates an isotopic signature very similar to a high-trophic level

  15. CRP1 Protein: (dis)similarities between Arabidopsis thaliana and Zea mays

    Science.gov (United States)

    Ferrari, Roberto; Tadini, Luca; Moratti, Fabio; Lehniger, Marie-Kristin; Costa, Alex; Rossi, Fabio; Colombo, Monica; Masiero, Simona; Schmitz-Linneweber, Christian; Pesaresi, Paolo

    2017-01-01

    Biogenesis of chloroplasts in higher plants is initiated from proplastids, and involves a series of processes by which a plastid able to perform photosynthesis, to synthesize amino acids, lipids, and phytohormones is formed. All plastid protein complexes are composed of subunits encoded by the nucleus and chloroplast genomes, which require a coordinated gene expression to produce the correct concentrations of organellar proteins and to maintain organelle function. To achieve this, hundreds of nucleus-encoded factors are imported into the chloroplast to control plastid gene expression. Among these factors, members of the Pentatricopeptide Repeat (PPR) containing protein family have emerged as key regulators of the organellar post–transcriptional processing. PPR proteins represent a large family in plants, and the extent to which PPR functions are conserved between dicots and monocots deserves evaluation, in light of differences in photosynthetic metabolism (C3 vs. C4) and localization of chloroplast biogenesis (mesophyll vs. bundle sheath cells). In this work we investigated the role played in the process of chloroplast biogenesis by At5g42310, a member of the Arabidopsis PPR family which we here refer to as AtCRP1 (Chloroplast RNA Processing 1), providing a comparison with the orthologous ZmCRP1 protein from Zea mays. Loss-of-function atcrp1 mutants are characterized by yellow-albinotic cotyledons and leaves owing to defects in the accumulation of subunits of the thylakoid protein complexes. As in the case of ZmCRP1, AtCRP1 associates with the 5′ UTRs of both psaC and, albeit very weakly, petA transcripts, indicating that the role of CRP1 as regulator of chloroplast protein synthesis has been conserved between maize and Arabidopsis. AtCRP1 also interacts with the petB-petD intergenic region and is required for the generation of petB and petD monocistronic RNAs. A similar role has been also attributed to ZmCRP1, although the direct interaction of ZmCRP1 with the

  16. A comparison of canopy evapotranspiration between perennial rhizomatous grasses and Zea mays

    Science.gov (United States)

    Hickman, G.; Bernacchi, C.; Dohleman, F.

    2008-12-01

    Perennial rhizomatous C4 grasses are currently considered one of the most promising vegetation types to accommodate a cellulosic feedstock based liquid fuel economy. The current focus on using these vegetation types as a source of renewable fuel has sparked numerous concerns associated with environmental impacts. Of particular interest is the impact that altering the composition of vegetation at the landscape scale would have on local and regional hydrological cycles. We hypothesize that evapotranspiration, ET, will be higher for perennial grasses relative to maize as a result higher leaf area, higher above-ground biomass and prolonged growing seasons. To test this hypothesis, a technique in which ET is estimated as the residual in the energy balance equation from measurements of net radiation and sensible and latent heat fluxes was employed. Measurements were made during the 2007 growing season for three replicate plots of the perennial rhizomatous grasses Miscanthus giganteus and Panicum virgatum, as well as for Zea mays planted at the University of Illinois South Farms. When averaged across the entire growing season, ET for M. giganteus was double relative to Z. mays, and 130% of P. virgatum ET. When compared over the periods in which all three species experienced mature and closed canopies (from day of year 200 to 250), M. giganteus still showed higher rates of ET compared with Z. mays, however, the increase was only ~15%. We conclude that ET associated with perennial alternative energy crops are higher relative to annual row crop; with most ET disparity, particularly for P. virgatum, being driven by phenology, quicker canopy closure and a prolonged growing season. Physiological rates of ET were highest for M. giganteus, followed by Z. mays, followed P. virgatum. Differences in phenology were more important than those of physiology for ET overshadowing effects from increased biomass associated with M. giganteus and/or a physiological difference between these

  17. Bacterial communities in the rhizosphere of amilaceous maize (Zea mays L. as assessed by pyrosequencing

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    David Correa-Galeote

    2016-07-01

    Full Text Available Maize (Zea mays L. is the staple diet of the native peasants in the Quechua region of the Peruvian Andes who continue growing it in small plots called chacras following ancestral traditions. The abundance and structure of bacterial communities associated with the roots of amilaceous maize has not been studied in Andean chacras. Accordingly, the main objective of this study was to describe the rhizospheric bacterial diversity of amilaceous maize grown either in the presence or the absence of bur clover cultivated in soils from the Quechua maize belt. Three 16S rRNA gene libraries, one corresponding to sequences of bacteria from bulk soil of a chacra maintained under fallow conditions, the second from the rhizosphere of maize-cultivated soils, and the third prepared from rhizospheric soil of maize cultivated in intercropping with bur clover were examined using pyrosequencing tags spanning the V4 and V5 hypervariable regions of the gene. A total of 26031 sequences were found that grouped into 5955 distinct operational taxonomic units which distributed in 309 genera. The numbers of OTUs in the libraries from the maize-cultivated soils were significantly higher than those found in the libraries from bulk soil. One hundred ninety seven genera were found in the bulk soil library and 234 and 203 were in those from the maize and maize/bur clover-cultivated soils. Sixteen out of the 309 genera had a relative abundance higher than 0.5% and the were (in decreasing order of abundance Gp4, Gp6, Flavobacterium, Subdivision3 genera incertae sedis of the Verrucomicrobia phylum, Gemmatimonas, Dechloromonas, Ohtaekwangia, Rhodoferax, Gaiella, Opitutus, Gp7, Spartobacteria genera incertae sedis, Terrimonas, Gp5, Steroidobacter and Parcubacteria genera incertae sedis. Genera Gp4 and Gp6 of the Acidobacteria, Gemmatimonas and Rhodoferax were the most abundant in bulk soil, whereas Flavobacterium, Dechloromonas and Ohtaekwangia were the main genera in the rhizosphere

  18. Potentially toxic elements in foodcrops: Triticum aestivum L., Zea mays L.

    Science.gov (United States)

    Bini, Claudio; Fontana, Silvia; Squizzato, Stefania; Minello, Fabiola; Fornasier, Flavio; Wahsha, Mohammad

    2013-04-01

    Soil is the basis of the ecosystems and of our system of food production. Crops can uptake heavy metals and potentially toxic elements from the soil and store them in the roots or translocate them to the aerial parts. Excessive content of these elements in edible parts can produce toxic effects and, through the food chain and food consumption, result in a potential hazard for human health. In this study soils and plants (spring wheat, Triticum aestivum L. and maize, Zea mays L.) from a tannery district in North-East Italy were analyzed to determine pedological characters, soil microbial indicators and the content of some major and micro-nutrients and potentially toxic elements (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, P, Pb, S, Zn, V). The soils of the area are moderately polluted; Cr is the most important inorganic contaminant, followed by Ni, Cu and V. Factor analysis evidenced that the contaminants are in part anthropogenic and in part geogenic. Major anthropogenic origin was detected for Cr, Ni (from industrial activities), Zn, Cu, Cd (from agriculture practices). Biological Absorption Coefficient (BAC) from soil to plant roots and Translocation factor (TF) within the plant were calculated; major nutrients (K, P, S) and some micronutrients (Cu, Zn, Mg, Mn) are easily absorbed and translocated, whilst other nutrients (Ca, Fe) and potentially toxic elements or micronutrients (Al, Cd, Cr, Ni, Pb, V) are not accumulated in the seeds of the two considered species. However, the two edible species proved differently able to absorb and translocate elements, and this suggests to consider separately every species as potential PHEs transporter to the food chain and to humans. Cr concentrations in seeds and other aerial parts (stem and leaves) of the examined plants are higher than the values found for the same species and for other cereals grown on unpolluted soils. Comparing the Cr levels in edible parts with recommended dietary intake, besides other possible Cr sources

  19. Selection and adaptation to high plant density in the Iowa Stiff Stalk synthetic maize (Zea mays L.) population: II. Plant morphology

    Science.gov (United States)

    The plant density at which Zea mays L. hybrids achieve maximum grain yield has increased throughout the hybrid era while grain yield on a per plant basis has increased little. Changes in plant characteristics including flag leaf angle, anthesis-silking interval (ASI), plant height, tassel branch num...

  20. Diapause hormone in the corn earworm, Helicoverpa zea: Optimum temperature for activity, structure-activity relationships, and efficacy in accelerating flesh fly pupariation

    Science.gov (United States)

    Diapause hormone (DH) effectively terminated pupal diapause in Helicoverpa zea. This effect was temperature-dependent, with an optimum of 21 degrees C. The dose-response curve indicated an ED50 of DH for diapause termination of approximately 100 pmol. The core sequence and essential amino acids w...

  1. The role of 2,4-D and auxin-binding proteins during the induction of embryogenic and non-embryogenic callus in Zea mays (L.).

    NARCIS (Netherlands)

    Bronsema, F.

    1998-01-01

    This thesis deals with the influence of the growth regulator 2,4-dichlorophenoxyacetic acid (2,4-D) on the induction of callus in cultured immature embryos of Zea mays (L). In maize, two types of embryogenic callus can be induced in immature zygotic embryos.Type I callus, which is compact in appeara

  2. The Effect of Morphaction on the Kinetics of Indol-3yl-Acetic Acid-2-14C Transport in Zea Mays L. Coleoptile Segments

    DEFF Research Database (Denmark)

    Naqvi, S. M.

    1972-01-01

    This paper elucidates the effects of chloroflurenol (morphactin, IT 3456) treatment on the kinetics of 14C-IAA transport through Zea mays L. (cv. Orla-266) coleoptile segments. Maximum inhibition of transport was achieved when chloroflurenol remained in contact with the tissue segments for at least...

  3. Cloning and Characterization of Purple Acid Phosphatase Phytases from Wheat (Triticum aestivum L.), Barley (Hordeum vulgare L.), Maize (Zea maize L.) and Rice (Oryza sativa L.)

    DEFF Research Database (Denmark)

    Dionisio, Giuseppe; Madsen, Claus Krogh; Holm, Preben Bach;

    2011-01-01

    Barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) possess a significant phytase activity in the mature grains. Maize (Zea mays L.) and rice (Oryza sativa L.) possess little or virtually no pre-formed phytase activity in the mature grain and depend fully on de novo synthesis during...

  4. Estela Restrepo Zea. El Hospital San Juan de Dios 1635-1895: una historia de la enfermedad, pobreza y muerte en Bogotá

    Directory of Open Access Journals (Sweden)

    María Angélica Ospina Martínez

    2012-09-01

    Full Text Available [...] Este libro de Estela Restrepo Zea, producto de su tesis doctoral, es una obra que traza, con gran minucia y rigurosidad,el devenir del Hospital San Juan de Dios en Bogotá, desde su creación, en el siglo XVII, hasta finales del siglo XIX. [...

  5. Estimation of long-terminal repeat element content in the Helicoverpa zea genome from next generation sequencing of reduced representation bacterial artificial chromosome (BAC) pools

    Science.gov (United States)

    The lepidopteran pest insect, Helicoverpa zea, feeds on cultivated corn and cotton crops in North America where control remains challenging due to evolution of resistance to chemical and transgenic insecticidal toxins, yet few genomic resources are available for this species. A bacterial artificial...

  6. Mode of inheritance and combining abilities for kernel row number, kernel number per row and grain yield in maize (Zea mays L.)

    NARCIS (Netherlands)

    Bocanski, J.; Sreckov, Z.; Nastasic, A.; Ivanovic, M.; Djalovic, I.; Vukosavljev, M.

    2010-01-01

    Bocanski J., Z. Sreckov, A. Nastasic, M. Ivanovic, I.Djalovic and M. Vukosavljev (2010): Mode of inheritance and combining abilities for kernel row number, kernel number per row and grain yield in maize (Zea mays L.) - Genetika, Vol 42, No. 1, 169- 176. Utilization of heterosis requires the study of

  7. Susceptibility of Helicoverpa zea and Heliothis virescens (Lepidoptera: noctuidae) to Vip3A insecticidal protein in VipCotTM cotton

    Science.gov (United States)

    Susceptibility of laboratory and field colonies of Helicoverpa zea (Boddie) and Heliothis virescens F. to Vip3A insecticidal protein was studied in diet incorporation and diet overlay assays from 2004 to 2008. Responses of field populations were compared to paired responses of University of Arkansas...

  8. Susceptibility of Helicoverpa zea and Heliothis virescens (Lepidoptera: Noctuidae) to Vip3A insecticidal protein expressed in VipCot™ cotton.

    Science.gov (United States)

    Ali, M I; Luttrell, R G

    2011-10-01

    Susceptibility of laboratory and field colonies of Helicoverpa zea (Boddie) and Heliothis virescens F. to Vip3A insecticidal protein was studied in diet incorporation and diet overlay assays from 2004 to 2008. Responses of field populations were compared to paired responses of University of Arkansas laboratory susceptible H. zea (LabZA) and H. virescens (LabVR) colonies. After 7d of exposure, observations were made on number of dead larvae (M) and the number of larvae alive but remaining as first instars (L1). Regression estimates using M (LC(50)) and M plus L1 (MIC(50)) data were developed for laboratory and field populations. Susceptibility of laboratory and field populations exposed to Vip3A varied among different batches of protein used over the study period. Within the same batch of Vip3A protein, susceptibilities of laboratory colonies of both species (LabZA and LabVR) were similar. Field colonies were significantly more susceptible to Vip3A than the respective reference colonies of both species. Within field populations, susceptibility to Vip3A varied up to 75-fold in H. zea and 132-fold in H. virescens in LC(50) estimates. Variabilities in MIC(50)s were up to 59- and 11-fold for H. zea and H. virescens, respectively.

  9. Sobre el Kelsen de Ferrajoli

    OpenAIRE

    Ruiz Manero, Juan

    2015-01-01

    El objeto de este trabajo es el de dar cuenta de las críticas a Kelsen contenidas en el último libro, todavía inédito, de Luigi Ferrajoli, Diritto e lógica. Dieci aporie nell'opera di Hans Kelsen, y formular algunas críticas a las tesis sostenidas en él por el propio Ferrajoli. Entre las críticas que el autor considera que cabe dirigir a este respecto a Ferrajoli, las principales afectan al carácter exclusivamente interno de la mirada ferrajoliana sobre el derecho, al carácter siempre opinabl...

  10. Manual de lecciones sobre objetos

    OpenAIRE

    2010-01-01

    Pautas para la enseñanza inicial con niños, apoyado con Objetos. Traducido por S. Bond (Profesor de la Universidad Nacional). Contiene: Desarrollo de la observación - Desarrollo de las ideas de forma - Ejercicios preliminares para enseñar a los niños a observar formas - Desarrollo de las ideas de dibujo -  de color - de número - de tamaño - de peso -  de sonido -  sobre el cuerpo humano - de lugar - morales

  11. Sobre el contenido del despertar

    OpenAIRE

    Badr, Marisa

    2013-01-01

    El presente trabajo tiene como propósito situar algunas referencias, sobre lo que Freud denomina “la perturbación” en los sueños. De este modo, intentaremos situar algunas consideraciones respecto a los sueños de angustia como principal antecedente del fracaso de la función del sueño y del principio del placer como principio rector del aparato anímico. Tomaremos como punto de partida los sueños de angustia, en “La interpretación de los sueños” de Sigmund Freud.

  12. Generalidades sobre las fibras artificiales

    OpenAIRE

    González Salcedo, Luis Octavio

    2012-01-01

    Las fibras han sido utilizadas como materia prima en la elaboración de otros productos, como telas, papel, artesanías, entre otros, y como material de refuerzo en diversas matrices cerámicas y metálicas, con el fin mejorar o ganar propiedades, en materiales compuestos denominados composites. Las fibras pueden ser clasificadas de acuerdo con su origen, en fibras naturales y fibras artificiales. Una amplia exploración sobre el uso de fibras vegetales ha sido realizada, sin embargo su uso ...

  13. Prototipo de RINA sobre Ethernet

    OpenAIRE

    Bergesio, Leonardo

    2013-01-01

    Este PFM se enmarca dentro del trabajo a realizar por el proyecto IRATI. IRATI es un proyecto STReP (Specific Targeted Research Project) financiado por la Unión Europea dentro del programa FP7 (Seventh Framework Programme for Research and Technological Development). El objetivo general de IRATI es conseguir una mayor compresión y exploración de RINA. El trabajo que se reportará en este PFM es (aproximadamente) la primera fase del diseño y desarrollo de un prototipo de RINA sobre Ethernet en e...

  14. Algunas conjeturas sobre fracciones egipcias

    OpenAIRE

    Mora, Lyda Constanza; Lima, Isaac

    2003-01-01

    A continuación se presentan algunas conjeturas sobre las fracciones, con base en el tratamiento que los Egipcios hacían en antigüedad. En la primera parte se hace una introducción a las fracciones unitarias, y la representación de fracciones con numerador dos por medio de la suma de fracciones unitarias distintas. En la segunda parte, se presentan algunas de las conjeturas halladas a partir de la determinación de regularidades presentes en adiciones entre fracciones cuya suma es una fracción ...

  15. Desarrollo de aplicaciones sobre SCTP

    OpenAIRE

    López Aragoneses, Jorge

    2009-01-01

    En el año 2000, el grupo SIGTRAN definió un nuevo protocolo de capa de transporte conocido como Stream Control Transmission Protocol (SCTP) pensado, inicialmente, para transportar señalización telefónica SS7 sobre IP. La intención fue proveer en IP algunas de las características de confiabilidad de SS7. Por su versatilidad, más tarde, se ha propuesto utilizarlo en otras áreas. Para tal fin, se ha realizado este proyecto fin de carrera, en el cual se estudiarán las características del protocol...

  16. Novel Vip3A Bacillus thuringiensis (Bt) maize approaches high-dose efficacy against Helicoverpa zea (Lepidoptera: Noctuidae) under field conditions: Implications for resistance management.

    Science.gov (United States)

    Burkness, Eric C; Dively, Galen; Patton, Terry; Morey, Amy C; Hutchison, William D

    2010-01-01

    Sweet corn, Zea mays L., transformed to express a novel vegetative insecticidal protein, Vip3A (event MIR162, Syngenta Seeds, Inc..), produced by the bacterium, Bacillus thuringiensis (Bt), was evaluated over four field seasons in Maryland and two field seasons in Minnesota for efficacy against the corn earworm, Helicoverpa zea (Boddie). Hybrids expressing the Vip3A protein and pyramided in hybrids also expressing the Cry1Ab Bt protein (event Bt11, ATTRIBUTE(®), Syngenta Seeds, Inc.) were compared to hybrids expressing only Cry1Ab or to genetically similar non-Bt hybrids each year. In addition to H. zea efficacy, results for Ostrinia nubilalis (Hübner) and Spodoptera frugiperda (J.E. Smith) are presented. Over all years and locations, the non-Bt hybrids, without insecticide protection, averaged between 43 and 100% ears infested with a range of 0.24 to 1.74 H. zea larvae per ear. By comparison, in the pyramided Vip3A x Cry1Ab hybrids, no larvae were found and only minimal kernel damage (likely due to other insect pests) was recorded. Hybrids expressing only Cry1Ab incurred a moderate level of H. zea feeding damage, with surviving larvae mostly limited to the first or second instar as a result of previously documented growth inhibition from Cry1Ab. These results suggest that the Vip3A protein, pyramided with Cry1Ab, appears to provide the first "high-dose" under field conditions and will be valuable for ongoing resistance management.

  17. Reducción del colesterol y aumento de la capacidad antioxidante por el consumo crónico de maíz morado (Zea mays L en ratas hipercolesterolémicas

    Directory of Open Access Journals (Sweden)

    Jorge Arroyo

    2007-04-01

    Full Text Available Objetivos: Determinar la actividad hipocolesterolémica y antioxidante del consumo crónico del extracto hidroalcohólico atomizado del maíz morado (Zea mays L en ratas hipercolesterolémicas. Materiales y métodos: Se utilizaron cinco grupos de seis ratas Holtzmann cada uno, uno sin hipercolesterolemia (control negativo, y cuatro con hipercolesterolemia inducida por consumo de colesterol puro vía oral durante 60 días: control positivo y tres para las dosis de 250, 500 y 1000 mg/kg, respectivamente. En el día 60 se determinaron los niveles séricos de colesterol total, triglicéridos y colesterol HDL (mg/dL, así como de malondialdehido (mmol/L para determinar la actividad antioxidante. Se comparó la diferencias de medias con ANOVA y test de Tukey. Resultados: Se observó una disminución del colesterol total en las ratas hipercolesterolémicas que consumieron dosis de 250 y 500 mg/kg en relación con el grupo control positivo (reducción de 21,5 y 11,2% respectivamente, p<0,01. No se observaron diferencias significativas sobre los niveles de triglicéridos y colesterol HDL. A mayor dosis se maíz morado se encontró una mayor reducción de radicales libres, con la dosis de 1000 mg/kg se redujo en 56,4% los niveles de malondialdehido (p< 0,01. Conclusiones: En condiciones experimentales, el consumo crónico del extracto hidroalcohólico atomizado de maíz morado disminuye los niveles de colesterol total y aumenta la capacidad antioxidante.

  18. Controle de plantas daninhas na cultura do milho (Zea mays L. por meio de herbicidas Weed control in maize (Zea mays L. with herbicides

    Directory of Open Access Journals (Sweden)

    C. A. L. dos Santos

    1979-12-01

    Full Text Available Com o objetivo de se verificar a ação do butylate, aplicado isoladamente e em mistura com atrazine, no controle de plantas daninhas da cultura do milho, foi instalado um experimento de campo em solo fino areno-argiloso. Foram utilizados os seguintes tratamentos: butylate a 2,80; 3,60 e 4,32 kg/ha (p.p.i.; butylate + atrazine a 3,24 + 0,80; 3,24 + 1,20 e 3,60 + 0,96 kg/ha (p.p.i.; atrazine a 3,00 kg/ha e atrazine + metolachlor a 1,40 + 2,10 kg/ha, ambos aplicados em pré-emergência e empregados como herbicidas padrão para a cultura. As plantas daninhas encontradas foram: tiririca - Cyperus rotundus L., carurú comum - .:maranthus viridis L., capim de colchão - Digitaria sanguinalis (L. Scop. e capim pé-de-galinha Eleusine indica (L. Gaertn. Butylate nas três doses apresentou-se bem contra C. rotundus e E. indica; nas doses de 3,60 e 4,32 kg foram obtidos bons resultados sobre D. sanguinalis. Butylate + atrazine controlou, nas três doses, todas as espécies incidentes, o mesmo ocorrendo com a mistura atrazine + metolachlor. Atrazine foi mais eficiente para A. viridis e E. indica. Nas condições em que foi conduzido o experimento nenhum dos herbicidas foi prejudicial para a cultura.Butylate at 2.80; 3.60 and 4.32 kg/ha and butylate + atrazine at. 3.24 + 0.80; 3.24 + 1.20 and 3.60 + 0.96 kg, were applied in preplant incorporated; atrazine at 3.00 kg and atrazine + metolachlor at 1.40 + 2.10 kg were applied in preemergence on corn. The weeds were represented by Cyperus rotundus L., Amaranthus viridis L., Digitaria sanguinalis (L. Scop. and Eleusine indica (L. Gaertn. Butylate + atrazine, in all rates, atrazine + metolachlor and atrazine gave good control of the weeds in general. Butylate, in the three rates, controlled C. rotundus and E. indica; at 3.60 and 4.32 kg/ha controlled well D. sanguinalis. The herbicides did not cause injuries to the crop.

  19. Blanco sobre blanco sobre blanco: Oiticica / Malevich / Nietzsche

    Directory of Open Access Journals (Sweden)

    Sérgio Martins

    2014-09-01

    Full Text Available El blanco sobre blanco, de Malevich, es una presencia fuerte en los escritos de Hélio Oiticica durante los setenta. Este artículo investiga los diferentes momentos del enlace de Oiticica con Malevich y el papel de esa noción en su pensamiento, articulándola a la referencia igualmente importante de Oiticica a John Cage y a la filosofía de Nietzsche. Así, es posible percibir tanto la centralidad del escrito para Oiticica en esta década, como la singularidad del modo de enunciación en él contenido, que puede ser descrito como aquel de un escrito manifiesto.

  20. PENGARUH PENAMBAHAN PUPUK NPK TERHADAP PRODUKSI BEBERAPA AKSESI TANAMAN JAGUNG (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Danny Pratikta

    2013-11-01

    Split Plot dengan tiga ulangan. Petak utama adalah Pupuk NPK (200, 300, 400 kg NPK ha-1 dan sub-plot adalah aksesi jagung (V1 = Srikandi Kuning x Manado Merah, V2 = Bisma x Srikandi Kuning, V3 = Srikandi Kuning x Bisma, dan V4 = Bisma x Manado Merah. Hasil percobaan dianalisis dengan menggunakan analisis varian (ANOVA dan Duncan Multiple Range Test (DMRT pada taraf α 5% (Hanafiah, 2005 dengan menggunakan program excel. Parameter pengamatan meliputi tinggi tanaman, jumlah daun atas dan dibawah tongkol jagung, umur berbunga jantan, umur berbungan betina, umur masak fisiologis, berat tongkol per petak (kg, berat pipilan per petak (kg, berat tongkol per tanaman (g, panjang tongkol isi (cm, lingkar tongkol (cm, berat 100 biji per tanaman (g, dan kandungan protein biji jagung (mg g-1. Hasil penelitian menunjukkan bahwa tidak ada perbedaan yang nyata antar perlakuan yang dicobakan pada parameter yang diamati. Perlakuan penambahan pupuk NPK tidak menunjukkan pengaruh yang nyata pada semua parameter. Berdasarkan pemilihan karakter, semua aksesi terpilih lebih tinggi dibanding varietas Bisma. Kandungan protein rata-rata aksesi yang diuji yaitu 11,14 ; 10,25 ; 10,95 ; dan 10,10 mg g-1 masing-masing untuk V1, V2, V3, dan V4. Kata Kunci: Pupuk NPK; Aksesi Jagung; Produksi How to citate: Pratikta D, S Hartatik, KA Wijaya. 2013. Pengaruh penambahan pupuk NPK terhadap produksi beberapa aksesi tanaman jagung (Zea mays L.. Berkala Ilmiah Pertanian 1(2: 19-21.

  1. INFLUENCE OF IRRIGATION AND NITROGEN FERTILIZATION ON YIELD AND QUALITY OF (Zea mays L. MAIZE GRAIN

    Directory of Open Access Journals (Sweden)

    Monika Marković

    2014-06-01

    Full Text Available The three years’ research (from 2010 to 2012, conducted on a trial field of the Institute of Agriculture in Osijek, is a part of a long stationary experiment. The objective of the research was the impact of irrigation (main factor, A, nitrogen fertilization (second factor, B, and the genotype (third factor, C on the grain yield and the quality of maize hybrids (Zea mays L. The irrigation scheduling was the main factor where A1 treatment was the control, rain-fed plot. In A2 treatment the soil water content was 60-100% of the field water capacity (FWC, while in the A3 treatment the soil water content was 80 to 100% FWC. Nitrogen fertilization as a sub factor, consisted of the three levels where B1 was the control treatment (0 kg N ha-1. In B2 treatment 100 kg N ha-1 was added, while in B3 treatment 200 kg N ha-1. Fall application (1/3 of all nitrogen was in the form of UREA. The same amount of nitrogen was applied in the pre-sowing period. During the vegetation period, two side dressings with CAN were carried out. The first side dressing (1/6 of nitrogen was done by cultivating the maize in 6-8 leaves phase, while the second one in 8 to 10 leaves phase (1/6 of nitrogen. Four maize hybrids (FAO 500 and 600 were used in the research, C1=OSSK596, C2=OSSK617, C3=OSSK602 and C4=OSSK552. The maize was irrigated by a traveling sprinkler system. The moment of irrigation was set by measuring soil moisture with the Watermark sensor (gypsum block. During the period of the research the weather conditions significantly varied, especially concerning the amount of precipitation. The year 2010 stands out as extremely wet (rainy, when a natural disaster of flood was proclaimed, due to high amount of precipitation, which had an influence on the results of the research. Analysis of variance showed statistically significant differences in yield in all three years of the research. Grain yield was higher as amount of irrigation water was higher, with an exception of

  2. Effects of Vermi compost and Compost tea Application on the Growth criteria of Corn (Zea mays

    Directory of Open Access Journals (Sweden)

    R Afsharmanesh

    2016-07-01

    Full Text Available Introduction Maize (Zea mays is a cereal crop that is grown widely throughout the world in a range of agroecological environments. .Its value as a cost-effective ruminant feed is one of the main reasons that farmers grow it. However, lack of nutrients such as N and P, are the principal obstacles - to crop production under low input agricultural systems leading to dependency on chemical fertilizers. Long-term use of chemical fertilizers destroy soil physicochemical properties and it reduced permeability which restricts root growth, nutrient uptake and plant production. Therefore, the use of organic fertilizers can help to enrich the soil root zone As a result growth and yield will improve. Materials and Methods In order to study the effects of different levels of vermicompost and foliar application of tea compost on growth characteristics of the hybrid maize genotype 713, a greenhouse experiment was conducted as a factorial experiment in randomized complete block design with three replications at the Vali-e-Asr University of Rafsanjan, during 2013. Treatments were included vermicompost (0, 5%, 10%, 15%, 20%, 25% and 30% pot weight and tea composts (foliar application, non-foliar application. Measured traits were included root dry weight, root volume, leaf dry weight, stem dry weight, macro nutrient concentration (N and P and micro nutrient concentration (Zn, Mn, Fe and Cu. All the data were subjected to the statistical analysis (two-way ANOVA using SAS software (SAS 9.1.3. Differences between the treatments were performed by Duncan’s multiple range test (DMRT at 1% confidence interval. Results and Discussion Results indicated that leaf and stem dry weight affected by the application of vermicompost and tea compost. However, the interaction effects had no significant effects on the leaf and stem dry weight. Application of tea compost increased 20% and 50% leaf dry weight and stem dry weight of corn compared to non- foliar application

  3. Activity of Acetolactate Synthase from Maize (Zea mays L. ) as Influenced by Chlorsulfuron and Tribenuron-methyl

    Institute of Scientific and Technical Information of China (English)

    FAN Zhi-jin; CHEN Jun-peng; HU Ji-ye; QIAN Chuan-fan; LI Zheng-ming

    2003-01-01

    Study on relative sensitivity of maize (Zea mays L. ) Nongda108 and Nongda3138 to sulfonylurea herbicide chlorsulfuron and tribenuron-methyl using maize taproot length by sand bioassy indicated that, Nongda3138 had higher tolerance to chlorsulfuron and tribenuron-methyl than Nongda108 did. Chlorsulfuron had stronger growth inhibition to maize Nongda108 and Nongda3138 than tribenuron-methyl did. Study on target enzyme of sulfonylurea herbicide acetolactate synthase (ALS) showed that, chlorsulfuron and tribenuron-methyl inhibited ALS in vitro strongly, and non-competitively. In the same concentration of inhibitors,chlorsuifuron had stronger ALS activity inhibition than tribenuron-methyl did. Lower level of chlorsulfuron and tribenuron-methyl has no ALS activity inhibition in vivo, the ALS inhibition only occurred in the condition of high concentration of chlorsulfuron and tribenuron-methyl in vivo.

  4. Involvement of an antioxidant defense system in the adaptive response to cadmium in maize seedlings (Zea mays L.).

    Science.gov (United States)

    Xu, Xianghua; Liu, Cuiying; Zhao, Xiaoyan; Li, Renying; Deng, Wenjing

    2014-11-01

    Chemical and biological analyses were used to investigate the growth response and antioxidant defense mechanism of maize seedlings (Zea mays L.) grown in soils with 0-100 mg kg(-1) Cd. Results showed that maize seedlings have strong abilities to accumulate and tolerate high concentrations of Cd. For soil with 50 mg kg(-1) Cd, the Cd contents in roots and shoots of maize seedlings are as large as 295.6 and 153.0 mg kg(-1) DW, respectively, without visible symptoms of toxicity. Lower soil Cd concentrations lead to a decrease in reduced glutathione (GSH) content in leaves of maize seedlings, whereas higher soil Cd concentrations resulted in an increase in the activities of superoxide dismutase, guaiacol peroxidase, catalase, and ascorbate peroxidase. Maize seedlings have strong capacities to adapt to low concentrations of Cd by consuming GSH and to develop an antioxidative enzyme system to defend against high-Cd stress.

  5. Influence of electrical fields and asymmetric application of mucilage on curvature of primary roots of Zea mays

    Science.gov (United States)

    Marcum, H.; Moore, R.

    1990-01-01

    Primary roots of Zea mays cv. Yellow Dent growing in an electric field curve towards the anode. Roots treated with EDTA and growing in electric field do not curve. When root cap mucilage is applied asymmetrically to tips of vertically-oriented roots, the roots curve toward the mucilage. Roots treated with EDTA curve toward the side receiving mucilage and toward blocks containing 10 mM CaCl2, but not toward "empty" agar blocks or the cut surfaces of severed root tips. These results suggest that 1) free calcium (Ca) is necessary for root electrotropism, 2) mucilage contains effector(s) that induce gravitropiclike curvature, and 3) mucilage can replace gravitropic effectors chelated by EDTA. These results are consistent with the hypothesis that the downward movement of gravitropic effectors to the lower sides of tips of horizontally-oriented roots occurs at least partially in the apoplast.

  6. Effects of As2O3 on DNA methylation, genomic instability, and LTR retrotransposon polymorphism in Zea mays.

    Science.gov (United States)

    Erturk, Filiz Aygun; Aydin, Murat; Sigmaz, Burcu; Taspinar, M Sinan; Arslan, Esra; Agar, Guleray; Yagci, Semra

    2015-12-01

    Arsenic is a well-known toxic substance on the living organisms. However, limited efforts have been made to study its DNA methylation, genomic instability, and long terminal repeat (LTR) retrotransposon polymorphism causing properties in different crops. In the present study, effects of As2O3 (arsenic trioxide) on LTR retrotransposon polymorphism and DNA methylation as well as DNA damage in Zea mays seedlings were investigated. The results showed that all of arsenic doses caused a decreasing genomic template stability (GTS) and an increasing Random Amplified Polymorphic DNAs (RAPDs) profile changes (DNA damage). In addition, increasing DNA methylation and LTR retrotransposon polymorphism characterized a model to explain the epigenetically changes in the gene expression were also found. The results of this experiment have clearly shown that arsenic has epigenetic effect as well as its genotoxic effect. Especially, the increasing of polymorphism of some LTR retrotransposon under arsenic stress may be a part of the defense system against the stress.

  7. Optimization of anaerobic digestion of a mixture of Zea mays and Miscanthus sacchariflorus silages with various pig manure dosages.

    Science.gov (United States)

    Bułkowska, K; Pokój, T; Klimiuk, E; Gusiatin, Z M

    2012-12-01

    Digestion of crop silage (Zea mays L. and Miscanthus sacchariflorus) with 0%, 7.5%, 12.5% and 25% pig manure as co-substrate was performed in continuous stirred-tank reactors, for a constant hydraulic retention time of 45 d and organic load rate of 2.1 g L(-1)d(-1). A matrix of correlations between biogas/methane production and parameters of anaerobic digestion was created in order to estimate process stability. The values of the correlation coefficients indicated that the most stable anaerobic digestion was achieved using 7.5% and 12.5% pig manure. In contrast, the positive correlation between ammonium and volatile fatty acids (r=0.8698, psilage alone, pig manure favored the production of biogas and methane; the highest production rates were obtained with 12.5% pig manure.

  8. Influence de l'age sur les caracteristiques photosynthetiques de la feuille de mais , Zea mays L.

    OpenAIRE

    Bethenod, Olivier; Jacob, Christine; Rode, J. C.; Morot-Gaudry, Jean-Francois

    1982-01-01

    L’assimilation nette maximale (N max) du maïs, Zea mays L., rapportée à l’unité de surface foliaire et de temps, reste stationnaire de juillet à août puis décroît de septembre à octobre durant le remplissage du grain. L’examen des courbes d’assimilation nette en fonction de la concentration en C02, sous éclairement saturant, montre que jusqu’au stade grain laiteux-pâteux, la photosynthèse maximale du maïs dépend du niveau du plateau de double saturation en C02 et en lumière (Pm). Du s...

  9. Karyotype of Zea luxurians and Z. mays subsp. mays using FISH/DAPI, and analysis of meiotic behavior of hybrids.

    Science.gov (United States)

    González, Graciela E; Poggio, Lidia

    2011-01-01

    The karyotypes of Zea luxurians and a race of maize from northwestern Argentina are described and compared using 4′,6-diamidino-2-phenylindole (DAPI) banding and fluorescent in situ hybridization (FISH) to localize the 180 bp knobs. The meiotic behavior of the F₁ artificial hybrids Z. luxurians × maize is also analyzed to determine the genomic relationships between both species. Neocentromere activity at knobs in the meiosis of the hybrids is particularly discussed. The meiotic behavior and the high pollen sterility of the hybrid revealed genetical and (or) chromosomal divergences, leading to postzygotic reproductive isolation among their parents. Here, we propose that maize shows lower genomic affinity to Z. luxurians than to other species of the genus with 2n = 20.

  10. Myo-inositol esters of indole-3-acetic acid are endogenous components of Zea mays L. shoot tissue

    Science.gov (United States)

    Chisnell, J. R.

    1984-01-01

    Indole-3-acetyl-myo-inositol esters have been demonstrated to be endogenous components of etiolated Zea mays shoots tissue. This was accomplished by comparison of the putative compounds with authentic, synthetic esters. The properties compared were liquid and gas-liquid chromatographic retention times and the 70-ev mass spectral fragmentation pattern of the pentaacetyl derivative. The amount of indole-3-acetyl-myo-inositol esters in the shoots was determined to be 74 nanomoles per kilogram fresh weight as measured by isotope dilution, accounting for 19% of the ester indole-3-acetic acid of the shoot. This work is the first characterization of an ester conjugate of indole-3-acetate acid from vegetative shoot tissue using multiple chromatographic properties and mass spectral identification. The kernel and the seedling shoot both contain indole-3-acetyl-myo-inositol esters, and these esters comprise approximately the same percentage of the total ester content of the kernel and of the shoot.

  11. Maize (Zea mays)-derived bovine trypsin: characterization of the first large-scale, commercial protein product from transgenic plants.

    Science.gov (United States)

    Woodard, Susan L; Mayor, Jocelyne M; Bailey, Michele R; Barker, Donna K; Love, Robert T; Lane, Jeffrey R; Delaney, Donna E; McComas-Wagner, Janet M; Mallubhotla, Hanuman D; Hood, Elizabeth E; Dangott, Lawrence J; Tichy, Shane E; Howard, John A

    2003-10-01

    Bovine trypsin (EC 3.4.21.4) is an enzyme that is widely used for commercial purposes to digest or process other proteins, including some therapeutic proteins. The biopharmaceutical industry is trying to eliminate animal-derived proteins from manufacturing processes due to the possible contamination of these products by human pathogens. Recombinant trypsin has been produced in a number of systems, including cell culture, bacteria and yeast. To date, these expression systems have not produced trypsin on a scale sufficient to fulfill the need of biopharmaceutical manufacturers where kilogram quantities are often required. The present paper describes commercial-level production of trypsin in transgenic maize (Zea mays) and its physical and functional characterization. This protease, the first enzyme to be produced on a large-scale using transgenic plant technology, is functionally equivalent to native bovine pancreatic trypsin. The availability of this reagent should allow for the replacement of animal-derived trypsin in the processing of pharmaceutical proteins.

  12. Zea mI, the maize homolog of the allergen-encoding Lol pI gene of rye grass.

    Science.gov (United States)

    Broadwater, A H; Rubinstein, A L; Chay, C H; Klapper, D G; Bedinger, P A

    1993-09-15

    Sequence analysis of a pollen-specific cDNA from maize has identified a homolog (Zea mI) of the gene (Lol pI) encoding the major allergen of rye-grass pollen. The protein encoded by the partial cDNA sequence is 59.3% identical and 72.7% similar to the comparable region of the reported amino acid sequence of Lol pIA. Southern analysis indicates that this cDNA represents a member of a small multigene family in maize. Northern analysis shows expression only in pollen, not in vegetative or female floral tissues. The timing of expression is developmentally regulated, occurring at a low level prior to the first pollen mitosis and at a high level after this postmeiotic division. Western analysis detects a protein in maize pollen lysates using polyclonal antiserum and monoclonal antibodies directed against purified Lolium perenne allergen.

  13. Recursos y enlaces sobre comunidades de aprendizaje

    OpenAIRE

    Ferrer Esteban, Gerard

    2005-01-01

    Obras y artículos sobre el proyecto Comunidades de Aprendizaje desarrollado en el Estado español. Tesis doctorales sobre comunidades de aprendizaje. Fundamentación teórica de las comunidades de aprendizaje. Sitios en Internet relacionados con las comunidades de aprendizaje y proyectos afines de desarrollo comunitario en contextos escolares.

  14. As monografias sobre plantas medicinais

    Directory of Open Access Journals (Sweden)

    Valdir F. Veiga Junior

    2008-09-01

    Full Text Available As monografias sobre plantas medicinais ou drogas vegetais contêm informações para atender não somente aos órgãos de regulamentação, mas também às empresas industriais farmacêuticas e farmácias, e mesmo ao público consumidor. Este artigo revê as monografias da Comissão E, do American Botanical Council, ESCOP, PDR e da Organização Mundial de Saúde em suas origens, objetivos e formatos. Duas publicações recentemente organizadas pela FIOCRUZ do Rio de Janeiro e as contribuições da Farmacopéia Brasileira também são avaliadas.

  15. Puente sobre el rio Lay

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1959-11-01

    Full Text Available El puente sobre el río Lay, salva el río formando un ángulo de 69° con la dirección de éste. Situado en el término municipal de la Reorthe (Francia, sus características principales se concentran en sus tres vigas pretensadas, de 30 m de longitud, prefabricadas, siguiendo los procedimientos Preyssinet, proyectadas por la Société Technique pour l'Utilisation de la Précontrainte, que también se encargó de la redacción del proyecto general de ejecución, cuya realización se encomendó a la empresa constructora Dodin, y de los métodos empleados para la colocación de las vigas en obra.

  16. Escenarios sobre el orden internacional

    Directory of Open Access Journals (Sweden)

    Luis Dallanegra Pedraza

    2012-01-01

    Full Text Available Luego de las grandes cambios que se dieron con la caída del Muro de Berlín y la desintegración en la URSS, se analizan, desde una perspectiva realista-sistémicaestructural, los componentes que intervienen en la generación del orden mundial, qué factores intervienen y cuáles son las diferentes aspiraciones respecto de las características que debería tener. Se tiene en especial consideración la creciente heterogeneización del sistema y la manera en que actores transnacionales operan como motores del futuro orden, predominando por sobre las posibilidades del actor históricamente dominante: el Estado-Nación. Se estudian las características principales del funcionamiento del sistema internacional y el significado de su marco institucional.

  17. Historicismo: notas sobre um paradigma

    Directory of Open Access Journals (Sweden)

    José D’Assunção Barros

    2012-08-01

    Full Text Available Este artigo tem por objetivo desenvolver algumas considerações sobre o Historicismo e sua possibilidade de ser examinado como um dos paradigmas que concorrem para o estabelecimento de uma história científica no século XIX. O primeiro ponto tratado é relativo às origens do paradigma Historicista na transição do século XVIII para o século XIX. Na sequência, aproximamo-nos da apropriação conservadora do paradigma historicista no novo contexto no qual a burguesia européia está assentada no Poder, combinando-se com a consolidação dos modernos estados-nações. A especificação das características deste paradigma constituem o principal ponto de análise

  18. Constitucional sobre la justicia ordinaria

    Directory of Open Access Journals (Sweden)

    José Luis Cea Egaña

    2005-01-01

    Full Text Available El artículo analiza el efecto vinculante y de irradiación de las sentencias del Tribunal Constitucional sobre el conjunto del ordenamiento jurídico y de sus órganos. El autor toma partido por la consideración de la ratio decidendi del fallo como vinculante junto al dictum de la sentencia respectiva. Se plantea la necesidad que la LOC del Tribunal Constitucional explicite los efectos vinculantes de los fallos respecto de los tribunales ordinarios y especiales. Finalmente analiza los efectos de la res iudicata en el ámbito del control reparador de constitucionalidad de preceptos legales en control concreto y en control abstracto.

  19. Efeitos da inclusão de forragem de leucena (Leucaena leucocephala (Lam. DeWit na qualidade da silagem de milho (Zea mays L. Effects of the inclusion of leucaena (Leucaena leucocephala (Lam. DeWit forage on corn silage quality

    Directory of Open Access Journals (Sweden)

    Rosana Cristina Pereira

    2004-08-01

    Full Text Available Este ensaio foi realizado no Departamento de Zootecnia da Universidade Federal de Lavras-MG, com o objetivo de avaliar os efeitos da adição de níveis crescentes de forragem de leucena (Leucaena leucocephala (Lam. DeWit no valor nutritivo da silagem de milho (Zea mays L.. O delineamento experimental usado foi o inteiramente casualizado com cinco tratamentos e três repetições. Os tratamentos consistiram de silagens de milho contendo 0, 10, 20, 30 e 40% de forragem de leucena com base na matéria verde. O material permaneceu ensilado por 30 dias em silos experimentais de canos de PVC. Determinaram-se os valores de pH e poder-tampão (PT e os teores de MS, PB, FDN, FDA e nitrogênio amoniacal (N-NH3. O aumento na proporção de leucena não alterou o teor de matéria seca das silagens e resultou em efeito linear positivo sobre os valores de pH, PT , PB e N-NH3 e efeito linear negativo sobre os teores de FDN e FDA. A inclusão de forragem de leucena até o nível de 40% é uma alternativa viável para a melhoria do valor nutritivo da silagem de milho.This assay was conducted at the Department of Animal Science of the University Federal of Lavras with the objective to evaluate the effects of the addition of growing levels of leucaena forage (Leucaena leucocephala (Lam. DeWit in the nutritive value of the corn silage (Zea mays L.. The experimental design used was the completely randomized with five treatments and three replicates. The treatments consisted of corn silage with 0, 10, 20, 30 and 40% of leucaena forage. The material remained ensiled for 30 days in experimental silos of PVC tubes. The values of pH and buffering power (BP and the contents of DM, CP, NDF, ADF and ammonium nitrogen (N-NH3 were determined. The dry matter contend of the silages was not affected by addition of leucaena. The increase in the ratio of leucaena resulted into a positive linear effect on the values of pH, BP, PB and N-NH3, and a negative effect on the contents of

  20. Puente sobre el rio Medway

    Directory of Open Access Journals (Sweden)

    Freeman, Fox, Ingenieros

    1963-02-01

    have been prestressed both longitudinally and transversally. Between the two circulation roadways an elastic barrier has been placed, supported on metal posts.El puente sobre el río Medway tiene la misión de salvar dicho río en el nuevo trazado de carretera necesario para aliviar el denso tráfico estival entre Dower y Londres. Está situado en las proximidades de la ciudad de Rochester. La estructura se ha construido utilizando las vías de concurso. De todos los tipos presentados se eligió una estructura de hormigón armado. La longitud total de la obra es de 1.000 m. Los tres tramos principales de la obra salvan el río. El central es de 152 m de luz, y los dos adyacentes son de 103 m cada uno. Los accesos tienen un total de 18 tramos, que arrojan una longitud de 654 m. La anchura del puente es de 34 m, y la calzada se ha subdividido en dos direcciones de tráfico de 7,30 m cada una y, además, se han dejado dos espaldones laterales de 2,40 m de anchura. En planta se puede admitir que el puente tiene una alineación recta con una ligerísima curva, y que en el plano vertical presenta una pendiente de desagüe entre las pilas 9 y 10. Los estribos son de hormigón armado: tipo celular el del este y de hormigón en masa el del oeste. Los estribos se apoyan sobre pilotes hexagonales de hormigón armado cuya circunferencia circunscrita tiene 55 cm de radio y de 12 a 20 m de longitud. Cuando el firme se hallaba a profundidades inferiores a 6 m, los estribos se cimentaban directamente sobre el firme. Las pilas constituyen pórtico y tienen una altura variable de 9 a 30 m sobre el nivel del suelo. Los tramos de acceso forman una estructura continua simplemente apoyada. Cada tramo se compone de ocho vigas longitudinales de 30 a 41 m de longitud y de 190 toneladas cada una. Estas vigas son del tipo pretensado y prefabricado. El tramo central es del tipo cantilever, constituido por dos brazos, de 30 m de longitud, formados por vigas cajón. Cada una de estas vigas consta

  1. Progresso da ferrugem tropical do milho (Zea mays L., sob diferentes tratamentos fungicidas Progress of the tropical rust of corn Zea mays L., under different fungicide treatments

    Directory of Open Access Journals (Sweden)

    Frank Magno da Costa

    2008-09-01

    Full Text Available A ferrugem tropical, cujo agente causal é o fungo Physopella zeae (Mains Cummins & Ramachar vem se destacando por sua agressividade à cultura do milho. Objetivou-se, com este trabalho, ajustar modelos matemáticos às curvas de progresso desta doença sob a ação de misturas de triazóis e estrobilurinas sobre o fungo na cultura do milho. O experimento foi conduzido em área experimental do Departamento de Fitossanidade da UNESP, Campus de Jaboticabal, no período de janeiro a maio de 2006, no delineamento de blocos casualizados completos com 6 tratamentos e 4 repetições. Os tratamentos utilizados foram (mL de p.c./ha: 1 - testemunha; 2 - epoxiconazole + pyraclostrobin, 500; 3 - epoxiconazole + pyraclostrobin, 750; 4 - azoxystrobin + cyproconazole, 300 + óleo mineral parafínico 0,50%, estes aplicados às plantas no estádio V8; 5 - azoxystrobin + cyproconazole, 300 + óleo mineral parafínico 0,50%, este aplicado às plantas no estádio V8 e repetido quando esta encontrava-se no início do pendoamento e 6- azoxystrobin + cyproconazole, 450 + óleo mineral parafínico 0,50%, aplicado às plantas no estádio V8. Foram realizadas sete avaliações da severidade da doença com intervalos semanais, traçando-se a partir dos dados obtidos nestas avaliações as curvas de progresso da doença analisadas por meio do ajuste a três modelos matemáticos (monomolecular, logístico e de Gompertz. Calculou-se ainda a Área Abaixo das Curvas de Progresso da Doença (AACPD, resultante de cada tratamento. Procedeu-se à análise de variância dos dados e as médias foram comparadas pelo teste Tukey ao nível de 5 % de probabilidade. Verificou-se que não houve diferença significativa entre os efeitos dos tratamentos 4, 5 e 6 e esses proporcionaram menor AACPD e ainda que esses apresentaram eficiência de controle de 92 %, 97 % e 98 %, respectivamente. Pelos resultados obtidos, pode-se concluir que o modelo monomolecular foi o que melhor se ajustou aos

  2. Impuesto sobre el Valor Añadido. Apuntes

    OpenAIRE

    2013-01-01

    Apuntes sobre las siguientes cuestiones relacionadas con el Impuesto sobre el Valor Añadido: deducciones; exportaciones e importaciones; operaciones intracomunitarias; prorrata y sectores diferenciados.

  3. Puente sobre el Oosterschelde, Holanda

    Directory of Open Access Journals (Sweden)

    Hoving, H. T.

    1967-03-01

    Full Text Available This new bridge, forming part of the Delta project, is made of concrete, and was built by successive overhangs. Precast units were mainly used. The bridge is 5,000 m long, and is 11.85 m wide. The main spans are 95 m in length, except one, which can be opened up to sea traffic, which is 40 m long. The free height of the bridge over the sea is 15 m, which is insufficient for large ships. This required that one of the spans, in deep water, should open up, on hinges, and provide free passage to large ships. The intermediate bridge supports are of special interest. They rest on piles which go down to 38 m. They are hollow, cylindrical, of 4.35 m external diameter, and are driven into the ground in several stages, as they penetrate through the sands at the bottom of the Oosterschelde. To drive them in, an excavating device, inside the pile, was utilised, and also a dredging and suction mechanism, to clean out the bottom, and allow the piles to sink by gravity. But when external friction did not allow this to happen, the piles were weighed down with up to 500 tons of ballast. A series of three of these piles, in a row, makes up each bridge support. A cross member over the pile heads supports, in turn, the bridge deck. The bridge was built in successive sections, overhanging from each support, and then finally connected with a central portion. Use of precast units has been very extensive, so that the bridge can be justiaflably regarded as being prefabricated.Este nuevo puente, que forma parte del Plan de obras denominadas del Delta, es de hormigón y se ha construido por el procedimiento de voladizos sucesivos, utilizando, en su mayor parte, elementos prefabricados. Tiene una longitud total de 5.000 m; una anchura de 11,85 m; tramos principales de 95 m de luz, salvo uno, levadizo, que tiene 40 m. La altura libre sobre las ag^uas del mar es de 15 m, que es insuficiente para las naves de gran tonelaje; esto exigió que uno de sus tramos, en aguas

  4. Differences on Pb accumulation among plant tissues of 25 varieties of maize (Zea mays)

    Institute of Scientific and Technical Information of China (English)

    DAI Quanlin; YUAN Jiangang; FANG Wei; YANG Zhongyi

    2007-01-01

    Pollution of agricultural land by heavy metals has imposed an increasingly serious risk to environmental and human health in recent years.Heavy metal pollutants may enter the human food chain through agricultural products and groundwater from the polluted soils.Progress has been made in the past decade on phytoremediation,a safe and inexpensive approach to remove contaminants from soil and water using plants.However,in most cases,agricultural land in China cannot afford to grow phytoremediator plants instead of growing crops due to food supply for the great population.Therefore,new and effective methods to decrease the risk of heavy metal pollution in crops and to clean the contaminated soils are urgently needed.If we can find crop germplasms (including species and varieties) that accumulate heavy metals in their edible parts,such as the leaves of vegetables or grains of cereals,at a level low enough for safe consumption,then we can grow these selected species or varieties in the lands contaminated or potentially contaminated by heavy metals.If we can find crop germplasms that take in low concentrations of heavy metals in their edible parts and high content of the metals in their inedible parts,then we can use these selected species or varieties for soil remediation.In this study,the feasibility of the method is assessed by analyzing Pb concentrations in edible and inedible parts of 25 varieties of maize (Zea mays) grown in Pb-contaminated soils.The soil concentrations of Pb were 595.55 mg/kg in the high Pb exposed treatment and 195.55 mg/kg in the control.The results showed that the Pb concentrations in different tissues were in the order of root > shoot ≌ leaf> grain.Compared with the control,the Pb concentrations in root,shoot and leaf were greatly increased under the high Pb exposed condition,while the increments of Pb concentration in grain were relatively lower.Under the high Pb exposure,the grain Pb concentrations of 12 varieties exceeded the maximal

  5. PERSPECTIVAS INFANTILES SOBRE LA TERRITORIALIDAD

    Directory of Open Access Journals (Sweden)

    Noelia Enriz

    2009-12-01

    Full Text Available En este trabajo nos proponemos un acercamiento a las diversas ideas infantiles sobre el territorio habitado, en el contexto particular de la población mbyá guaraní de Misiones. La fragilidad territorialidad a la que es expuesta la población indígena en Argentina se manifiestan cotidianamente en diversas áreas. La población mbyá, ha sido surcada por los límites de los estados nacionales de Paraguay, Brasil y Argentina. La sedentarización y los cercamientos de tierras en los diferentes estados, han impulsado transformaciones de las lógicas de subsistencia, de habitación y organización comunitaria. En el caso de la provincia de Misiones la acreditación burocrática de los títulos de tierras se encuentra aplazada, el estado no se compromete con la concreción de este derecho.

  6. Sobre a psicopatologia dos atos

    Directory of Open Access Journals (Sweden)

    Roberto Calazans

    2015-07-01

    Full Text Available Este artigo pretende apresentar a psicopatologia dos atos a partir do esquema de Jacques Lacan sobre a angústia. Diferenciamos os acting-out, a passagem ao ato, os sintomas, as inibições e a angústia fazendo uma duplicação do esquema de Lacan levando em consideração os registros do simbólico, do real e do imaginário. Esse esquema permite uma abordagem da questão dos atos do sujeito sem cair em uma perplexidade do clínico, nem na confusão entre os atos e a ação. Permite também uma melhor orientação do clínico em relação às diversas modalidades de respostas subjetivas que não se restringem à questão sintomática, que é o campo inaugural da clínica psicanalítica desde a sua fundação por Sigmund Freud. Acreditamos contribuir, assim, para um maior esclarecimento desse esquema no ensino de Lacan e para que ele possa servir de orientação para o tratamento dos atos do sujeito na clínica.

  7. Puente colgante sobre el Lillebaelt

    Directory of Open Access Journals (Sweden)

    Ostenfeld, Chr.

    1971-09-01

    Full Text Available This bridge, which was opened to traffic in October 1970 over the Lillebaelt, is the first of its kind in Denmark. It consists of a central span of 600 m, and two lateral ones of 240 m length each. The suspension cables, each 1,500 m, are the world's largest prefabricated cables. The bridge has original features, such as flaps on the main box girder, and new design of the anchorage blocks. These and other details are described in the article.Inaugurado en octubre de 1970, el puente colgante sobre el Lillebselt es el primer puente danés de este tipo. Consta de un tramo central de 600 m y dos tramos laterales de 240 m. Los cables sustentantes son, con sus 1.500 m de longitud, los mayores cables prefabricados del mundo. El puente presenta características origínales —empleo de «flaps» en la vigacajón de la superestructura, concepción nueva de los macizos de anclaje...— que, junto con el sistema de ejecución y las demás particularidades de la obra, son descritas en el artículo.

  8. Estudo multicasos sobre atividades inovativas

    Directory of Open Access Journals (Sweden)

    Sonia Regina Hierro Parolin

    2013-09-01

    Full Text Available Em estudos sobre competitividade argumenta-se que as empresas necessitam de estratégias baseadas em inovações e de capacidades internas em constantes e intensas transformações, não somente nos padrões tecnológicos, mas também no encadeamento do processo de gestão das atividades inovativas, como processos dinâmicos, não lineares e diversificados, em função de múltiplos fatores dos ambientes interno e externo. Para contribuir com essas discussões, neste artigo apresenta-se um estudo multicasos em quatro indústrias de médio e grande portes, de segmentos, densidades tecnológicas e históricos com inovações diferentes entre si. Como principais resultados, salientam-se o encadeamento das atividades inovativas como parte de uma estratégia organizacional para obter resultados com inovação e a afluência de todas as pessoas, e não somente as alocadas em pesquisa e desenvolvimento, para o cumprimento dessa estratégia.

  9. Pengaruh Dosis Pupuk Zeorea dan Konsentrasi ZPT Dekamon 22.43 L Terhadap Pertumbuhan dan Produksi Tanaman Jagung Manis (Zea mays saccharata Sturt.)

    OpenAIRE

    Aruan, Marnaek H.

    2012-01-01

    MARNAEK HASIHOLAN ARUAN, "Pengaruh Dosis Pupuk Zeorea dan Konsentrasi Zat Pengatur Tumbuh Dekamon 22.43 L Terhadap Pertumbuhan dan Produksi Tanaman Jagung Manis (Zea mays sacchurata Sturt.)", dibawah bimbingan ibu Ir. Hj. Sabar Ginting, MS selaku ketua komisi pembimbing dan bapak Ir Toga Simannngkalit, MS selaku anggota komisi pembimbing. Penelitian ini telah dilaksanakan di Jalan Matahari Raya Kecamatan Medan Helvetia mulai dari. bulan Januari ,2004 - April 2004. Tujuan dari penelitian...

  10. Study of cell-differentiation and assembly of photosynthetic proteins during greening of etiolated Zea mays leaves using confocal fluorescence microspectroscopy at liquid-nitrogen temperature.

    Science.gov (United States)

    Shibata, Yutaka; Katoh, Wataru; Tahara, Yukari

    2013-04-01

    Fluorescence microspectroscopy observations were used to study the processes of cell differentiation and assemblies of photosynthesis proteins in Zea mays leaves under the greening process. The observations were done at 78K by setting the sample in a cryostat to avoid any undesired progress of the greening process during the measurements. The lateral and axial spatial resolutions of the system were 0.64μm and 4.4μm, respectively. The study revealed the spatial distributions of protochlorophyllide (PChld) in both the 632-nm-emitting and 655-nm-emitting forms within etiolated Zea mays leaves. The sizes of the fluorescence spots attributed to the former were larger than those of the latter, validating the assignment of the former and latter to the prothylakoid and prolamellar bodies, respectively. In vivo microspectroscopy observations of mature Zea mays leaves confirmed the different photosystem II (PS I)/photosystem I (PS II) ratio between the bundle sheath (BS) and mesophyll (MS) cells, which is specific for C4-plants. The BS cells in Zea mays leaves 1h after the initiation of the greening process tended to show fluorescence spectra at shorter wavelength side (at around 679nm) than the MS cells (at around 682nm). The 679-nm-emitting chlorophyll-a form observed mainly in the BS cells was attributed to putative precursor complexes to PS I. The BS cells under 3-h greening showed higher relative intensities of the PS I fluorescence band at around 735nm, suggesting the reduced PS II amount in the BS cells in this greening stage.

  11. Biological effects of pollution and problems of the environment in the region of Birsesti (Town of Jiu), Romania. [Triticum vulgare; Zea mays; Brassica oleracea; Vitis vinifera

    Energy Technology Data Exchange (ETDEWEB)

    Ionescu, A.; Neamu, G.

    1973-01-01

    The vegetation around Birsesti showed diminished chlorophyll pigment by as much as 20% below control plants. In Triticum vulgare, Zea mays and Brassica oleracea there was a reduction in functioning stomata. The mechanical blockage by cement dust induced changes in the leaf veins. Plant productivity and dry weight were reduced. A reduction of 250% in Vitis vinifera cultivation was reduced to about 1/3 that of unaffected areas. 16 references, 7 figures, 1 table.

  12. Isolasi Nanokristal Selulosa Dari Tongkol Jagug (Zea mays L) Dengan Metode hidrolisa Menggunakan Pelarut Dimetil Asetamida/Litium Klorida (DMAc/LiCl)

    OpenAIRE

    Kasrawati

    2014-01-01

    Isolation of cellulose nanocrystal from corncorb (Zea Mays, L) by hydrolyzed method using solvent dimethyl acetamide/lithium chloride (DMAc/LiCl) have been done. Corncorb was delignificated with 3.5% nitric acid and sodium nitrite, then the residue was treated with 17.5% sodium hydroxide, and bleached with 10% hydrogen peroxide. Cellulose nanocrystal was done by hydrolysis method using solvent dimethyl acetamide / lithium klodida (DMAc/LiCl). From the image of transmission electron microscopy...

  13. Determination of Some Agronomıcal Characteristics of Local Flint Corn (Zea mays L. indurata) Genotypes in The Black Sea Region of Turkey

    OpenAIRE

    2014-01-01

    In this study, 84 flint corn (Zea mays L. indurata) genotypes were used. Twelwe agronomical characteristics of 84 flint local corn genotypes were examined. Local corn genotypes were collected from 12 cities in the Black Sea Region in 2008 and field and laboratuary studies were completed in 2009. Variance analysis showed that there were high variations in most of the agronomical characteristics. At this study, plant height, ear height, stalk diameter, number of leaf per plant, ear length, ear ...

  14. Tanggap Pertumbuhan dan Produksi Jagung (Zea mays L.) Varietas Pioneer-23 Terhadap Berbagai Komposisi Vermikompos dengan Pupuk Anorganik (N,P,K)

    OpenAIRE

    Nasution, Efrida Sari

    2013-01-01

    EFRIDA SARI NASUTION: The Response of Growth and Yield of Maize (Zea mays L.) Pioneer 23 Variety on Some Compotition of Vermicompost and Anorganic Fertilizer (N,P,K), supervised by MARIATI SINURAYA and ASIL BARUS. The research has been conducted to investigate the response of growth and yield of maize on some compotition of organic (vermicompost) and anorganic (N,P,K) fertilizer at Bunga Terompet street, Sempakata village chief, Medan Selayang subdistrict head, with a height...

  15. Sorghum seed maturity affects the weight and feeding duration of immature corn earworm, Helicoverpa zea, and fall armyworm, Spodoptera frugiperda, in the laboratory.

    Science.gov (United States)

    Soper, Alysha M; Whitworth, R Jeff; McCornack, Brian P

    2013-01-01

    Corn earworm, Helicoverpa zea Boddie (Lepidoptera: Noctuidae), and fall armyworm, Spodoptera frugiperda J.E. Smith, are occasional pests in sorghum, Sorghum bicolor L. Moench (Poales: Poaceae), and can be economically damaging when conditions are favorable. Despite the frequent occurrence of mixed-species infestations, the quantitative data necessary for developing yield loss relationships for S. frugiperda are not available. Although these species share similar biological characteristics, it is unknown whether their damage potentials in developing grain sorghum panicles are the same. Using no-choice feeding assays in the laboratory, this study examined larval growth and feeding duration for H. zea and S. frugiperda in the absence of competition. Each species responded positively when exposed to sorghum seed in the soft-dough stage, supporting evidence for the interactions between host-quality and larval growth and development. The results of this study also confirmed the suitability of using laboratory-reared H. zea to develop sorghum yield loss estimates in the field, and provided insights into the biological responses of S. frugiperda feeding on developing sorghum seed.

  16. Bioactivity of a water extract of boldus (Peumus boldus Molina against Spodoptera frugiperda (J.E. Smith and Helicoverpa zea Boddie (Lepidoptera: Noctuidae

    Directory of Open Access Journals (Sweden)

    Gonzalo Silva

    2013-06-01

    Full Text Available The insecticidal properties of water-extract of Peumus boldus Molina and its effect on the development cycle and feeding habits of Spodoptera frugiperda J.E. Smith and Helicoverpa zea Boddie were evaluated under laboratory conditions in concentrations of 0.25, 0.5, 1.0, 2.0, 4.0, and 8.0% (w/w. Spodoptera frugiperda was the most susceptible with 75% mortality at 7 d at 8% P. boldus concentration, while H. zea had only 30% mortality. LC50 was 2.31 mL kg-1 for S. frugiperda and 16.05 mL kg¹ for H. zea. When the extract concentration increased in the diet, larval size and weight, percentage of pupation and number of adults decreased, and the time required to reach those states was greater. Neonate larvae fed primarily on the diet with the lower extract concentration and the control was preferred by more than 50% of larvae. Inhibition of feeding, growth, weight gain of 3rd instar larvae as well as new biomass production decreased with concentration of the extract.

  17. Comentarios y reflexiones sobre las operaciones financieras

    OpenAIRE

    Pavón Bautista, María Mercedes

    1995-01-01

    En este trabajo se hacen comentarios y reflexiones sobre los tipos de operaciones financieras simples, operaciones financieras de constitución de capitales y operaciones financieras de amortización.

  18. Los derechos de autor sobre obtenciones vegetales

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    Rosario Silva Gilli

    2015-01-01

    Full Text Available Contenido: Las creaciones en la agricultura. Los derechos de autor sobre obtenciones vegetales. El Convenio Internacional para la protección de las obtenciones vegetales (París 1961 y sus revisiones de Ginebra 1972, 1978,1991 Objeto de la protección legal. Condiciones del cultivar. Alcance de la protección. La protección de obtenciones vegetales en el Mercosur. Los Derechos de autor en el Mercosur. El Protocolo de Armonización de normas sobre Propiedad Intelectual en el Mercosur. El Acuerdo de Cooperación y facilitación sobre la protección de las obtenciones vegetales en los Estados Partes del Mercosur.  Alcance de la normativa Mercosur. Los Derechos sobre cultivares en Uruguay. Los Derechos de autor como derechos humanos. ¿Derechos de autor vs. derecho de propiedad intelectual? Reflexión final

  19. Reflexiones sobre pedagogías intensivas

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    Vizcaíno Pinilla Mercedes

    1996-06-01

    Full Text Available

    En el presente artículo se pretende recoger los conceptos filosóficos y los principios pedagógicos que orientan las pedagogías intensivas. Como valor primordial se encuentra la acción comunicativa como el eje sobre el cual se construyen las pedagogías intensivas orienta sobre las calidades que debe tener el maestro para desarrollarlas

  20. Cross-resistance to toxins used in pyramided Bt crops and resistance to Bt sprays in Helicoverpa zea.

    Science.gov (United States)

    Welch, Kara L; Unnithan, Gopalan C; Degain, Ben A; Wei, Jizhen; Zhang, Jie; Li, Xianchun; Tabashnik, Bruce E; Carrière, Yves

    2015-11-01

    To delay evolution of resistance by insect pests, farmers are rapidly increasing their use of transgenic crops producing two or more Bacillus thuringiensis (Bt) toxins that kill the same pest. A key condition favoring durability of these "pyramided" crops is the absence of cross-resistance between toxins. Here we evaluated cross-resistance in the major lepidopteran pest Helicoverpa zea (Boddie) to Bt toxins used in pyramids. In the laboratory, we selected a strain of this pest with Bt toxin Cry1Ac followed by selection with MVP II, a formulation containing a hybrid protoxin that is identical to Cry1Ac in the active portion of the toxin and 98.5% identical overall. We calculated the resistance ratio as the EC50 (concentration causing mortality or failure to develop beyond the first instar of 50% of larvae) for the laboratory-selected strain divided by the EC50 for its field-derived parent strain that was not selected in the laboratory. The resistance ratio was 20.0-33.9 (mean=27.0) for MVP II, 57.0 for Cry1Ac, 51.3 for Cry1A.105, 22.4 for Cry1Ab, 3.3 for Cry2Ab, 1.8 for Cry1Fa, and 1.6 for Vip3Aa. Resistance ratios were 2.9 for DiPel ES and 2.0 for Agree VG, which are commercial Bt spray formulations containing Cry1Ac, other Bt toxins, and Bt spores. By the conservative criterion of non-overlap of 95% fiducial limits, the EC50 was significantly higher for the selected strain than its parent strain for MVP II, Cry1Ac, Cry1A.105, Cry1Ab, Cry2Ab and DiPel ES. For Cry1Fa, Vip3Aa, and Agree VG, significantly lower susceptibility to a high concentration indicated low cross-resistance. The resistance ratio for toxins other than Cry1Ac was associated with their amino acid sequence similarity to Cry1Ac in domain II. Resistance to Cry1Ac and the observed cross-resistance to other Bt toxins could accelerate evolution of H. zea resistance to currently registered Bt sprays and pyramided Bt crops.

  1. PERSPECTIVAS INFANTILES SOBRE LA TERRITORIALIDAD

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    NOELIA ENRIZ

    2009-12-01

    Full Text Available In this paper we propose a different approach to children's ideas about the geographical area in the particular context of the Mbyá Guarani population, from Misiones (Argentine. The territorial fragility, that is exposed to the indigenous people in Argentina aremanifested daily in several areas. Mbyá population, has been crossed by the boundaries of national states of Paraguay, Brazil and Argentina. The sedentary and enclosures land processes in different states, have prompted changes in the logic of subsistence, housing and community organization. In Misiones province case, bureaucratic accreditation of land titles is postponed, the state is not committed to the realization of this right.RESUMEN: En este trabajo nos proponemos un acercamiento a las diversas ideas infantiles sobre el territorio habitado, en el contexto particular de la población mbyá guaraní de Misiones. La fragilidad territorialidad a la que es expuesta la población indígena en Argentina se manifiestan cotidianamente en diversas áreas. La población mbyá, ha sido surcada por los límites de los estados nacionales de Paraguay, Brasil y Argentina. La sedentarización y los cercamientos de tierras en los diferentes estados, han impulsado transformaciones de las lógicas de subsistencia, de habitación y organización comunitaria. En el caso de la provincia de Misiones la acreditación burocrática de los títulos de tierras se encuentra aplazada, el estado no se compromete con la concreción de este derecho.

  2. Consideraciones preliminares sobre la credibilidad

    Directory of Open Access Journals (Sweden)

    Fernando Verdugo

    2004-01-01

    Full Text Available A modo de introducción al Seminario Interno de Profesores de la Facultad de Teología de la PUC, el autor recuerda, en primer lugar, lo que suele entenderse por "credibilidad" y, también, algunos de los criterios generales por los cuales algo o alguien adquiere la calidad de creíble (el que sea razonable, relevante o significativo, capaz de producir gozo estético, etc.. Luego, en la parte más extensa, el autor vuelve a llamar la atención sobre la necesidad de atender a los condicionamientos culturales de la fe cristiana. La fe, al igual que toda experiencia humana, está culturalmente mediada. Tomar conciencia de ese hecho y asumir las consecuencias metodológicas es indispensable para una teología que quiere poner atención a los desafíos actuales y contribuir así a la credibilidad del cristianismoThis article reprints the introductory session to the internal seminar of lecturers from the Faculty of Theology of the UC. In the first place, the author sums up what is usually understood by `credibility' and the general criteria through which something or someone gains credibility (being reasonable, relevant or significant, capable of producing aesthetic pleasure. Then the author deals at length with the need to take notice of the cultural conditionings of the Christian faith. The faith, the same as any other human experience, is culturally mediated. It is crucial for theology to become aware of this fact and come to terms with its methodological consequences, if it wants to face current challenges and so contribute to the credibility of Christianity

  3. Sobre sujeitos racionais e apaixonados

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    Dílson Ferreira da Cruz

    2009-12-01

    Full Text Available

    Desde seu nascimento, a Retórica convive com um cisma insuperável: de um lado, Platão afirma que o orador deve buscar o bom e o verdadeiro; tem de seguir a lógica e sustentar-se com um discurso sóbrio, no qual prevalece a razão, o logos, e para o qual as coisas interessam pelo que são em si mesmas. No outro extremo da ágora está Cícero, para quem a Retórica não tem que procurar pela essência de nada, mas fazer com que a opinião do orador, seja ela verdadeira ou não, passe a ser também a do auditório. Para tanto, a lógica, tão acalentada por Platão, é de bem pouca valia, pois o orador, se quiser ter sucesso, deve levar os corações da cólera à doçura ou desta àquela. Como se vê, é uma retórica alicerçada sobre o pathos, ou, como diriam os semioticistas, no estado das almas. Este artigo se propõe a pensar essa questão utilizando o instrumental da semiótica dita tensiva com o objetivo de mostrar que, no discurso do grego, predominam as valências ligadas à extensidade, ao inteligível, às características dos objetos; ao passo que, nos ensinamentos do romano, são as valências relacionadas à intensidade, ao sensível, que se destacam.

  4. Effects of Liquid Organic Fertilizer on Time of Tasselling, Time of Silking and Grain Yield of Maize (Zea mays

    Directory of Open Access Journals (Sweden)

    Enujeke, E. C. and Ojeifo, I. M.

    2013-04-01

    Full Text Available A study was carried out in the Teaching and Research Farm of Delta State University, Asaba Campus from August to December in 2005 and repeated between March and July, 2006 to evaluate the response of maize (Zea mays to liquid organic fertilizer. The study was conducted using a split plot fitted into randomized complete block design. Liquid organic fertilizer was diluted at the rate of 60 ml of the product to 15 litres of water and applied to maize foliage, topsoil, foliage and topsoil at the rates of 5l/ha, 10l/ha, 151/ha, l8l/ha, 201/ha and 251/ha. The result obtained indicated a positive influence of liquid organic fertilizer on time of tasselling, time of silking and grain yield of maize. Liquid organic fertilizer significantly reduced the times of tasselling and silking, and increased grain yield of maize. Based on this study, it is recommended that 151/ha of liquid organic fertilizer which produced 5.6tha’ in 2005 and 6.1tha’ of dry grain yield 2006 be applied on the topsoil of maize plant with a view to maximally exploit the great economic potentials of the crop.

  5. Comparison of Three Methods for Determination of Root Hydraulic Conductivity of Maize (Zea mays L.) Root System

    Institute of Scientific and Technical Information of China (English)

    LI Qing-ming; LIU Bin-bin

    2010-01-01

    Three techniques of root pressure probe,pressure chamber and high pressure flow meter were used to measure the hydraulic conduetivities (Lp,) of whole root systems of young maize (Zea mays L.) seedlings grown hydroponically under either drought or normal water conditions.Compared to normal water conditions,drought stress simulated by polyethylene glycol 6 000 (osmotic potential=-0.2 MPa) reduced Lp,in the root system by over 50%.It indicated that water permeability in the roots decreased significantly when plants suffered from water shortages.Moreover,there was no significant difference (P<0.05) on the Lpr values in the root systems developed under a given water stress regime among the three techniques used.Therefore,all three methods are acceptable to study the hydraulic conductivity of maize seedling root systems.We have also highlighted some of the technical limitations of each method.It can be inferred that the root pressure probe is preferable for young maize seedlings because it is subtle and has the additional ability to determine solute transport properties,but the method is time consuming.Other advantages and disadvantages of each technique are discussed in order to acquaint researchers with basic information that could contribute to their choice of an appropriate technique for future studies.

  6. Determination of Genetic Coefficients of Some Maize (Zea mays L. Cultivars of Iran for Application in Crop Simulation Models

    Directory of Open Access Journals (Sweden)

    S Rahimi Moghaddam

    2015-09-01

    Full Text Available A field experiment was conducted at the research field of the University of Lorestan in 2011 as a randomized complete block design with three replications to estimate genetic coefficients of some maize (Zea mays L. cultivars. Treatments include six maize cultivars (T.V.C.767 and S.C.704 from late maturing group, T N.S640 and Maxima from mid-maturing group, and Koppany and D.C.370 from early maturing group. Results showed that there were significant differences among cultivars in terms of stem dry weight, maximum number of kernel per ear, thermal time from the flag leaf appearance to flowering, thermal time from flowering to maturity, phyllochron interval, grain weight, maximum plant height and minimum growth degree days during vegetative period. The highest (649.2 and lowest (350.6 maximum number of kernel per ear belonged to cultivars S.C.704 and D.C.370, respectively. Also, the highest and lowest stem dry weight, phyllochron interval and maximum plant height belonged to cultivars S.C.704 and D.C.370, respectively. Among genetic coefficients, the minimum growth degree days required for vegetative growth and the maximum number of kernel per ear had the greatest correlation with grain yield (r=0.72 and r=0.84, respectively. Overall, the results portrayed that the estimated genetic coefficients of the cultivars are not identical in different models and varied in a defined range.

  7. Comparative impact of genetically modified and non modified maize (Zea mays L.) on succeeding crop and associated weed.

    Science.gov (United States)

    Ibrahim, Muhammad; Ahmed, Naseer; Ullah, Faizan; Shinwari, Zabta Khan; Bano, Asghari

    2016-04-01

    This research work documents the comparative impact of genetically modified (GM) (insect resistance) and non modified maize (Zea mays L.) on growth and germination of succeeding crop wheat (Triticum aestivum L.) and associated weed (Avena fatua L.). The aqueous extracts of both the GM and non-GM maize exhibited higher phenolic content than that of methanolic extracts. Germination percentage and germination index of wheat was significantly decreased by GM methanolic extract (10%) as well as that of non-GM maize at 3% aqueous extract. Similarly germination percentage of weed (Avena fatua L.) was significantly reduced by application of 3% and 5% methanolic GM extracts. All extracts of GM maize showed non-significant effect on the number of roots, root length and shoot length per plant but 5% and 10% methanolic extracts of non-GM maize significantly increased the number of roots per plant of wheat seedling. Similarly, 10% methanolic extract of GM maize significantly increased the number of roots per plant of weed seedling. Methanolic extracts of GM and non-GM maize (3% and 5%) significantly decreased the protease activity in wheat as compared to untreated control.

  8. Antioxidant, α-glucosidase and xanthine oxidase inhibitory activity of bioactive compounds from maize (Zea mays L.).

    Science.gov (United States)

    Nile, Shivraj H; Park, Se W

    2014-01-01

    Chemical investigations into maize (Zea mays L.) kernels yielded phenolic compounds, which were structurally established using chromatographic and spectroscopic methods. The isolated phenolic compounds from maize kernel were examined in vitro for their antioxidant abilities by DPPH (2,2-diphenyl-1-picryl hydrazine) radical, OH radical scavenging activity, and reducing ability, along with α-glucosidase and xanthine oxidase (XO) inhibition. The isolated maize phenolics revealed significant xanthine oxidase and α-glucosidase inhibitory activity to that of allopurinol and acarbose in vitro and in vivo, respectively. The kinetics study with xanthine oxidase revealed competitive type of inhibition by isolated maize vanillic acid (M2), ferulic acid (M5), 3'-methoxyhirsutrin (M7), and peonidin-3-glucoside (M10) as compared to control allopurinol. Overall, with few exceptions, all the phenolic compounds from maize kernel revealed significant biological activities with all parameters examined. Also, the phenolic compounds from maize were found to be more reactive toward DPPH radical and had considerable reducing ability and OH radical scavenging activity. These findings suggest that maize kernel phenolic compounds can be considered as potential antioxidant, α-glucosidase, and XO inhibitory agents those might be further explored for the design of lead antioxidant, antidiabetic and antigout drug candidates using in vivo trials.

  9. Accumulation of 5-hydroxynorvaline in maize (Zea mays) leaves is induced by insect feeding and abiotic stress.

    Science.gov (United States)

    Yan, Jian; Lipka, Alexander E; Schmelz, Eric A; Buckler, Edward S; Jander, Georg

    2015-02-01

    Plants produce a wide variety of defensive metabolites to protect themselves against herbivores and pathogens. Non-protein amino acids, which are present in many plant species, can have a defensive function through their mis-incorporation during protein synthesis and/or inhibition of biosynthetic pathways in primary metabolism. 5-Hydroxynorvaline was identified in a targeted search for previously unknown non-protein amino acids in the leaves of maize (Zea mays) inbred line B73. Accumulation of this compound increases during herbivory by aphids (Rhopalosiphum maidis, corn leaf aphid) and caterpillars (Spodoptera exigua, beet armyworm), as well as in response to treatment with the plant signalling molecules methyl jasmonate, salicylic acid and abscisic acid. In contrast, ethylene signalling reduced 5-hydroxynorvaline abundance. Drought stress induced 5-hydroxynorvaline accumulation to a higher level than insect feeding or treatment with defence signalling molecules. In field-grown plants, the 5-hydroxynorvaline concentration was highest in above-ground vegetative tissue, but it was also detectable in roots and dry seeds. When 5-hydroxynorvaline was added to aphid artificial diet at concentrations similar to those found in maize leaves and stems, R. maidis reproduction was reduced, indicating that this maize metabolite may have a defensive function. Among 27 tested maize inbred lines there was a greater than 10-fold range in the accumulation of foliar 5-hydroxynorvaline. Genetic mapping populations derived from a subset of these inbred lines were used to map quantitative trait loci for 5-hydroxynorvaline accumulation to maize chromosomes 5 and 7.

  10. Influence of microgravity on root-cap regeneration and the structure of columella cells in Zea mays

    Science.gov (United States)

    Moore, R.; McClelen, C. E.; Fondren, W. M.; Wang, C. L.

    1987-01-01

    We launched imbibed seeds and seedlings of Zea mays into outer space aboard the space shuttle Columbia to determine the influence of microgravity on 1) root-cap regeneration, and 2) the distribution of amyloplasts and endoplasmic reticulum (ER) in the putative statocytes (i.e., columella cells) of roots. Decapped roots grown on Earth completely regenerated their caps within 4.8 days after decapping, while those grown in microgravity did not regenerate caps. In Earth-grown seedlings, the ER was localized primarily along the periphery of columella cells, and amyloplasts sedimented in response to gravity to the lower sides of the cells. Seeds germinated on Earth and subsequently launched into outer space had a distribution of ER in columella cells similar to that of Earth-grown controls, but amyloplasts were distributed throughout the cells. Seeds germinated in outer space were characterized by the presence of spherical and ellipsoidal masses of ER and randomly distributed amyloplasts in their columella cells. These results indicate that 1) gravity is necessary for regeneration of the root cap, 2) columella cells can maintain their characteristic distribution of ER in microgravity only if they are exposed previously to gravity, and 3) gravity is necessary to distribute the ER in columella cells of this cultivar of Z. mays.

  11. Alternative Splicing and Differential Expression of Two Transcripts of Nicotine Adenine Dinucleotide Phosphate Oxidase B Gene from Zea mays

    Institute of Scientific and Technical Information of China (English)

    Fan Lin; Yun Zhang; Ming-Yi Jiang

    2009-01-01

    With the exception of rice, little is known about the existence of respiratory burst oxidase homolog (rboh) gene in cereals. The present study reports the cloning and analysis of a novel rboh gene, termed ZmrbohB, from maize (Zea mays L.). The full-length cDNA of ZmrbohB encodes a 942 amino acid protein containing all of the respiratory burst oxidase homolog catalytically critical motifs.Altemative splicing of ZmrbohB has generated two transcript isoforms, ZmrbohB-α and -β. Spliced transcript ZmrbohB-β retains an unspliced intron 11 that carries a premature termination codon and probably leads to nonsense-mediated mRNA decay. Expression analysis showed that two splice isoforms were differentially expressed in various tissues and at different developmental stages, and the major product was ZmrbohB-α. The transcripts of ZmrbohB-α accumulated markedly when the maize seedlings were subjected to various abiotic stimuli, such as wounding, cold (4℃), heat (40℃), UV and salinity stress. In addition, several abiotic stimuli also affected the alternative splicing pattern of ZmrbohB except wounding. These results provide new insight into roles in the expression regulation of plant rboh genes and suggest that ZmrbohB gene may play a role in response to environmental stresses.

  12. Effect of Soil Aging on the Phytoremediation Potential of Zea mays in Chromium and Benzo[a]Pyrene Contaminated Soils.

    Science.gov (United States)

    Chigbo, Chibuike

    2015-06-01

    This study compared the phytoremediation potential of Zea mays in soil either aged or freshly amended with chromium (Cr) and benzo[a]pyrene (B[a]P). Z. mays showed increased shoot biomass in aged soils than in freshly spiked soils. The shoot biomass in contaminated soils increased by over 50% in aged soil when compared to freshly amended soils, and over 29% more Cr was accumulated in the shoot of Z. mays in aged soil than in freshly amended soil. Planting Z. mays in aged soil helped in the dissipation of more than 31% B[a]P than in freshly spiked soil, but in the absence of plants, there seemed to be no difference between the dissipation rates of B[a]P in freshly and aged co-contaminated soil. Z. mays seemed to enhance the simultaneous removal of Cr and B[a]P in aged soil than in freshly spiked soil and hence can be a good plant choice for phytoremediation of co-contaminated soils.

  13. Root growth, secondary root formation and root gravitropism in carotenoid-deficient seedlings of Zea mays L

    Science.gov (United States)

    Ng, Y. K.; Moore, R.

    1985-01-01

    The effect of ABA on root growth, secondary-root formation and root gravitropism in seedlings of Zea mays was investigated by using Fluridone-treated seedlings and a viviparous mutant, both of which lack carotenoids and ABA. Primary roots of seedlings grown in the presence of Fluridone grew significantly slower than those of control (i.e. untreated) roots. Elongation of Fluridone-treated roots was inhibited significantly by the exogenous application of 1 mM ABA. Exogenous application of 1 micromole and 1 nmole ABA had either no effect or only a slight stimulatory effect on root elongation, depending on the method of application. The absence of ABA in Fluridone-treated plants was not an important factor in secondary-root formation in seedlings less than 9-10 d old. However, ABA may suppress secondary-root formation in older seedlings, since 11-d-old control seedlings had significantly fewer secondary roots than Fluridone-treated seedlings. Roots of Fluridone-treated and control seedlings were graviresponsive. Similar data were obtained for vp-9 mutants of Z. mays, which are phenotypically identical to Fluridone-treated seedlings. These results indicate that ABA is necessary for neither secondary-root formation nor for positive gravitropism by primary roots.

  14. Growth, cadmium uptake and accumulation of maize (Zea mays L.) under the effects of arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Liu, Lingzhi; Gong, Zongqiang; Zhang, Yulong; Li, Peijun

    2014-12-01

    The effects of three arbuscular mycorrhizal fungi isolates on Cd uptake and accumulation by maize (Zea mays L.) were investigated in a planted pot experiment. Plants were inoculated with Glomus intraradices, Glomus constrictum and Glomus mosseae at three different Cd concentrations. The results showed that root colonization increased with Cd addition during a 6-week growth period, however, the fungal density on roots decreased after 9-week growth in the treatments with G. constrictum and G. mosseae isolates. The percentage of mycorrhizal colonization by the three arbuscular mycorrhizal fungi isolates ranged from 22.7 to 72.3%. Arbuscular mycorrhizal fungi inoculations decreased maize biomass especially during the first 6-week growth before Cd addition, and this inhibitory effect was less significant with Cd addition and growth time. Cd concentrations and uptake in maize plants increased with arbuscular mycorrhizal fungi colonization at low Cd concentration (0.02 mM): nonetheless, it decreased at high Cd concentration (0.20 mM) after 6-week growth period. Inoculation with G. constrictum isolates enhanced the root Cd concentrations and uptake, but G. mosseae isolates showed the opposite results at high Cd concentration level after 9 week growth period, as compared to non-mycorrhizal plants. In conclusion, maize plants inoculated with arbuscular mycorrhizal fungi were less sensitive to Cd stress than uninoculated plants. G. constrictum isolates enhanced Cd phytostabilization and G. mosseae isolates reduced Cd uptake in maize (Z. mays L.).

  15. Function of isoamylase-type starch debranching enzymes ISA1 and ISA2 in the Zea mays leaf.

    Science.gov (United States)

    Lin, Qiaohui; Facon, Maud; Putaux, Jean-Luc; Dinges, Jason R; Wattebled, Fabrice; D'Hulst, Christophe; Hennen-Bierwagen, Tracie A; Myers, Alan M

    2013-12-01

    Conserved isoamylase-type starch debranching enzymes (ISAs), including the catalytic ISA1 and noncatalytic ISA2, are major starch biosynthesis determinants. Arabidopsis thaliana leaves require ISA1 and ISA2 for physiological function, whereas endosperm starch is near normal with only ISA1. ISA functions were characterized in maize (Zea mays) leaves to determine whether species-specific distinctions in ISA1 primary structure, or metabolic differences in tissues, are responsible for the differing ISA2 requirement. Genetic methods provided lines lacking ISA1 or ISA2. Biochemical analyses characterized ISA activities in mutant tissues. Starch content, granule morphology, and amylopectin fine structure were determined. Three ISA activity forms were observed in leaves, two ISA1/ISA2 heteromultimers and one ISA1 homomultimer. ISA1 homomultimer activity existed in mutants lacking ISA2. Mutants without ISA2 differed in leaf starch content, granule morphology, and amylopectin structure compared with nonmutants or lines lacking both ISA1 and ISA2. The data imply that both the ISA1 homomultimer and ISA1/ISA2 heteromultimer function in the maize leaf. The ISA1 homomultimer is present and functions in the maize leaf. Evolutionary divergence between monocots and dicots probably explains the ability of ISA1 to function as a homomultimer in maize leaves, in contrast to other species where the ISA1/ISA2 heteromultimer is the only active form.

  16. Unraveling the role of dark septate endophyte (DSE) colonizing maize (Zea mays) under cadmium stress: physiological, cytological and genic aspects

    Science.gov (United States)

    Wang, Jun-Ling; Li, Tao; Liu, Gao-Yuan; Smith, Joshua M.; Zhao, Zhi-Wei

    2016-02-01

    A growing body of evidence suggests that plant root-associated fungi such as dark septate endophytes (DSE) can help plants overcome many biotic and abiotic stresses, of great interest is DSE-plant metal tolerance and alleviation capabilities on contaminated soils. However, the tolerance and alleviation mechanisms involved have not yet been elucidated. In the current study, the regulation and physiological response of Zea mays to its root-associated DSE, Exophiala pisciphila was analyzed under increased soil Cd stress (0, 10, 50, 100 mg kg‑1). Under Cd stress, DSE inoculation significantly enhanced the activities of antioxidant enzymes and low-molecular weight antioxidants, while also inducing increased Cd accumulation in the cell wall and conversion of Cd into inactive forms by shoot and root specific regulation of genes related to metal uptake, translocation and chelation. Our results showed that DSE colonization resulted in a marked tolerance to Cd, with a significant decrease in cadmium phytotoxicity and a significant increase in maize growth by triggering antioxidant systems, altering metal chemical forms into inactive Cd, and repartitioning subcellular Cd into the cell wall. These results provide comprehensive evidence for the mechanisms by which DSE colonization bioaugments Cd tolerance in maize at physiological, cytological and molecular levels.

  17. Studies on the growth and indole-3-acetic acid and abscisic acid content of Zea mays seedlings grown in microgravity

    Science.gov (United States)

    Schulze, A.; Jensen, P. J.; Desrosiers, M.; Buta, J. G.; Bandurski, R. S.

    1992-01-01

    Measurements were made of the fresh weight, dry weight, dry weight-fresh weight ratio, free and conjugated indole-3-acetic acid, and free and conjugated abscisic acid in seedlings of Zea mays grown in darkness in microgravity and on earth. Imbibition of the dry kernels was 17 h prior to launch. Growth was for 5 d at ambient orbiter temperature and at a chronic accelerational force of the order of 3 x 10(-5) times earth gravity. Weights and hormone content of the microgravity seedlings were, with minor exceptions, not statistically different from seedlings grown in normal gravity. The tissues of the shuttle-grown plants appeared normal and the seedlings differed only in the lack of orientation of roots and shoots. These findings, based upon 5 d of growth in microgravity, cannot be extrapolated to growth in microgravity for weeks, months, and years, as might occur on a space station. Nonetheless, it is encouraging, for prospects of bioregeneration of the atmosphere and food production in a space station, that no pronounced differences in the parameters measured were apparent during the 5 d of plant seedling growth in microgravity.

  18. The solute specificity profiles of nucleobase cation symporter 1 (NCS1) from Zea mays and Setaria viridis illustrate functional flexibility.

    Science.gov (United States)

    Rapp, Micah; Schein, Jessica; Hunt, Kevin A; Nalam, Vamsi; Mourad, George S; Schultes, Neil P

    2016-03-01

    The solute specificity profiles (transport and binding) for the nucleobase cation symporter 1 (NCS1) proteins, from the closely related C4 grasses Zea mays and Setaria viridis, differ from that of Arabidopsis thaliana and Chlamydomonas reinhardtii NCS1. Solute specificity profiles for NCS1 from Z. mays (ZmNCS1) and S. viridis (SvNCS1) were determined through heterologous complementation studies in NCS1-deficient Saccharomyces cerevisiae strains. The four Viridiplantae NCS1 proteins transport the purines adenine and guanine, but unlike the dicot and algal NCS1, grass NCS1 proteins fail to transport the pyrimidine uracil. Despite the high level of amino acid sequence similarity, ZmNCS1 and SvNCS1 display distinct solute transport and recognition profiles. SvNCS1 transports adenine, guanine, hypoxanthine, cytosine, and allantoin and competitively binds xanthine and uric acid. ZmNCS1 transports adenine, guanine, and cytosine and competitively binds, 5-fluorocytosine, hypoxanthine, xanthine, and uric acid. The differences in grass NCS1 profiles are due to a limited number of amino acid alterations. These amino acid residues do not correspond to amino acids essential for overall solute and cation binding or solute transport, as previously identified in bacterial and fungal NCS1, but rather may represent residues involved in subtle solute discrimination. The data presented here reveal that within Viridiplantae, NCS1 proteins transport a broad range of nucleobase compounds and that the solute specificity profile varies with species.

  19. Phytomanagement of Cd-contaminated soils using maize (Zea mays L.) assisted by plant growth-promoting rhizobacteria.

    Science.gov (United States)

    Moreira, Helena; Marques, Ana P G C; Franco, Albina R; Rangel, António O S S; Castro, Paula M L

    2014-01-01

    Zea mays (L.) is a crop widely cultivated throughout the world and can be considered suitable for phytomanagement due to its metal resistance and energetic value. In this study, the effect of two plant growth-promoting rhizobacteria, Ralstonia eutropha and Chryseobacterium humi, on growth and metal uptake of Z. mays plants in soils contaminated with up to 30 mg Cd kg(-1) was evaluated. Bacterial inoculation increased plant biomass up to 63% and led to a decrease of up to 81% in Cd shoot levels (4-88 mg Cd kg(-1)) and to an increase of up to 186% in accumulation in the roots (52-134 mg Cd kg(-1)). The rhizosphere community structure changed throughout the experiment and varied with different levels of Cd soil contamination, as revealed by molecular biology techniques. Z. mays plants inoculated with either of the tested strains may have potential application in a strategy of soil remediation, in particular short-term phytostabilization, coupled with biomass production for energy purposes.

  20. [3H]Indole-3-acetyl-myo-inositol hydrolysis by extracts of Zea mays L. vegetative tissue

    Science.gov (United States)

    Hall, P. J.; Bandurski, R. S.

    1986-01-01

    [3H]Indole-3-acetyl-myo-inositol was hydrolyzed by buffered extracts of acetone powders prepared from 4 day shoots of dark grown Zea mays L. seedlings. The hydrolytic activity was proportional to the amount of extract added and was linear for up to 6 hours at 37 degrees C. Boiled or alcohol denatured extracts were inactive. Analysis of reaction mixtures by high performance liquid chromatography demonstrated that not all isomers of indole-3-acetyl-myo-inositol were hydrolyzed at the same rate. Buffered extracts of acetone powders were prepared from coleoptiles and mesocotyls. The rates of hydrolysis observed with coleoptile extracts were greater than those observed with mesocotyl extracts. Active extracts also catalyzed the hydrolysis of esterase substrates such as alpha-naphthyl acetate and the methyl esters of indoleacetic acid and naphthyleneacetic acid. Attempts to purify the indole-3-acetyl-myo-inositol hydrolyzing activity by chromatographic procedures resulted in only slight purification with large losses of activity. Chromatography over hydroxylapatite allowed separation of two enzymically active fractions, one of which catalyzed the hydrolysis of both indole-3-acetyl-myo-inositol and esterase substrates. With the other enzymic hydrolysis of esterase substrates was readily demonstrated, but no hydrolysis of indole-3-acetyl-myo-inositol was ever detected.

  1. Iron fractions in the apoplast of intact root tips of Zea mays L. seedlings affected by nitrogen form

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The effects of ammonium (NH+4- N ) and ni trate (NO-3- N ) Were examined on Fe fractions and FeCN (ferricyanide) reductase activity in intact root tips (0-3 em)of young maize (Zea mays L. cv. Lenz) in solution culture by using short-term experiment under controlled Fe deficiency conditions (containing high HCO-3 concentration in preculture solution). The results showed that Fe( II ) concentrations in root tip apoplast of maize were only 20-40 nmol/g FW which accounted for 7%-13% of total Fe. Most of Fe in root tips existed as Fe(Ⅲ) compounds. Imposition of the roots to NH+4 - N or NO-3 - N for 60 min led to an increase of Fe( II ) in root tip apoplast. NH+4 - N led to an increased concentration of Fe( II ) and exchangeable Fe (Fe( II ) and Fe (III)) in root tips, while NO-3 - N increased FeCN reductaseactivity. The relationship between pH and Fe fractions,FeCN reductase activity was also discussed.``

  2. Significance of diazotrophic plant growth-promoting Herbaspirillum sp. GW103 on phytoextraction of Pband Zn by Zea mays L.

    Science.gov (United States)

    Praburaman, Loganathan; Park, Sung-Hee; Cho, Min; Lee, Kui-Jae; Ko, Jeong-Ae; Han, Sang-Sub; Lee, Sang-Hyun; Kamala-Kannan, Seralathan; Oh, Byung-Taek

    2017-01-01

    Microbe-assisted phytoremediation has been considered a promising measure for the remediation of heavy metal-polluted soil. The aim of this study was to assess the effect of diazotrophic plant growth-promoting Herbaspirillum sp. GW103 on growth and lead (Pb) and zinc (Zn) accumulation in Zea mays L. The strain GW103 exhibited plant growth-promoting traits such as indole-3-acetic acid, siderophores, and 1-aminocyclopropane-1-carboxylic deaminase. Treatment of Z. mays L. plants with GW103 significantly increased 19, 31, and 52% of plant biomass and 10, 50, and 126% of chlorophyll a contents in Pb, Zn, and Pb + Zn-amended soils, respectively. Similarly, the strain GW103 significantly increased Pb and Zn accumulation in shoots and roots of Z. mays L., which were 77 and 25% in Pb-amended soil, 42 and 73% in Zn-amended soil, and 27 and 84% in Pb + Zn-amended soil. Furthermore, addition of GW103 increased 8, 12, and 7% of total protein content, catalase, and superoxide dismutase levels, respectively, in Z. mays L. plants. The results pointed out that isolate GW103 could potentially reduce the phytotoxicity of metals and increase Pb and Zn accumulation in Z. mays L. plant.

  3. Auxin as an inducer of asymmetrical division generating the subsidiary cells in stomatal complexes of Zea mays.

    Science.gov (United States)

    Livanos, Pantelis; Giannoutsou, Eleni; Apostolakos, Panagiotis; Galatis, Basil

    2015-01-01

    The data presented in this work revealed that in Zea mays the exogenously added auxins indole-3-acetic acid (IAA) and 1-napthaleneacetic acid (NAA), promoted the establishment of subsidiary cell mother cell (SMC) polarity and the subsequent subsidiary cell formation, while treatment with auxin transport inhibitors 2,3,5-triiodobenzoic acid (TIBA) and 1-napthoxyacetic acid (NOA) specifically blocked SMC polarization and asymmetrical division. Furthermore, in young guard cell mother cells (GMCs) the PIN1 auxin efflux carriers were mainly localized in the transverse GMC faces, while in the advanced GMCs they appeared both in the transverse and the lateral ones adjacent to SMCs. Considering that phosphatidyl-inositol-3-kinase (PI3K) is an active component of auxin signal transduction and that phospholipid signaling contributes in the establishment of polarity, treatments with the specific inhibitor of the PI3K LY294002 were carried out. The presence of LY294002 suppressed polarization of SMCs and prevented their asymmetrical division, whereas combined treatment with exogenously added NAA and LY294002 restricted the promotional auxin influence on subsidiary cell formation. These findings support the view that auxin is involved in Z. mays subsidiary cell formation, probably functioning as inducer of the asymmetrical SMC division. Collectively, the results obtained from treatments with auxin transport inhibitors and the appearance of PIN1 proteins in the lateral GMC faces indicate a local transfer of auxin from GMCs to SMCs. Moreover, auxin signal transduction seems to be mediated by the catalytic function of PI3K.

  4. Growth and graviresponsiveness of primary roots of Zea mays seedlings deficient in abscisic acid and gibberellic acid

    Science.gov (United States)

    Moore, R.; Dickey, K.

    1985-01-01

    The objective of this research was to determine if gibberellic acid (GA) and/or abscisic acid (ABA) are necessary for graviresponsiveness by primary roots of Zea mays. To accomplish this objective we measured the growth and graviresponsiveness of primary roots of seedlings in which the synthesis of ABA and GA was inhibited collectively and individually by genetic and chemical means. Roots of seedlings treated with Fluridone (an inhibitor of ABA biosynthesis) and Ancymidol (an inhibitor of GA biosynthesis) were characterized by slower growth rates but not significantly different gravicultures as compared to untreated controls. Gravicurvatures of primary roots of d-5 mutants (having undetectable levels of GA) and vp-9 mutants (having undectable levels of ABA) were not significantly different from those of wild-type seedlings. Roots of seedlings in which the biosynthesis of ABA and GA was collectively inhibited were characterized by gravicurvatures not significantly different for those of controls. These results (1) indicate that drastic reductions in the amount of ABA and GA in Z. mays seedlings do not significantly alter root graviresponsiveness, (2) suggest that neither ABA nor GA is necessary for root gravicurvature, and (3) indicate that root gravicurvature is not necessarily proportional to root elongation.

  5. Genetic characterization and linkage disequilibrium mapping of resistance to gray leaf spot in maize(Zea mays L.)

    Institute of Scientific and Technical Information of China (English)

    Liyu; Shi; Xiangling; Lv; Jianfeng; Weng; Hanyong; Zhu; Changlin; Liu; Zhuanfang; Hao; Yu; Zhou; Degui; Zhang; Mingshun; Li; Xiaoke; Ci; Xinhai; Li; Shihuang; Zhang

    2014-01-01

    Gray leaf spot(GLS),caused by Cercospora zeae-maydis,is an important foliar disease of maize(Zea mays L.)worldwide,resistance to which is controlled by multiple quantitative trait loci(QTL).To gain insights into the genetic architecture underlying the resistance to this disease,an association mapping population consisting of 161 inbred lines was evaluated for resistance to GLS in a plant pathology nursery at Shenyang in 2010 and 2011.Subsequently,a genome-wide association study,using 41,101 single-nucleotide polymorphisms(SNPs),identified 51 SNPs significantly(P<0.001)associated with GLS resistance,which could be converted into 31 QTL.In addition,three candidate genes related to plant defense were identified,including nucleotidebinding-site/leucine-rich repeat,receptor-like kinase genes similar to those involved in basal defense.Two genic SNPs,PZE-103142893 and PZE-109119001,associated with GLS resistance in chromosome bins 3.07 and 9.07,can be used for marker-assisted selection(MAS)of GLS resistance.These results provide an important resource for developing molecular markers closely linked with the target trait,enhancing breeding efficiency.

  6. Biochemical Adaptations in Zea mays Roots to Short-Term Pb(2+) Exposure: ROS Generation and Metabolism.

    Science.gov (United States)

    Kaur, Gurpreet; Kaur, Shubhpreet; Singh, Harminder Pal; Batish, Daizy Rani; Kohli, Ravinder Kumar; Rishi, Valbha

    2015-08-01

    The present study investigated the effect of lead (0, 16, 40 and 80 mg L(-1) Pb2+) exposure for 3, 12 and 24 h on root biochemistry in hydroponically grown Zea mays (maize). Pb2+ exposure (80 mg L(-1)) enhanced malondialdehyde content (239%-427%), reactive carbonyl groups (425%-512%) and H2O2 (129%-294%) accumulation during 3-24 h of treatment, thereby indicating cellular peroxidation and oxidative damage. The quantitative estimations were in accordance with in situ detection of ROS generation (using 2',7'-dichlorodihydrofluorescein diacetate dye) and H2O2 accumulation. Pb2+ treatment significantly reduced ascorbate and glutathione content during 3-24 h of exposure. On the contrary, levels of non-protein thiols were enhanced by 3-11.8 time over control in response to 16-80 mg L(-1) Pb2+ treatment, after 24 h. A dose-dependent induction in ascorbate peroxidase and lipoxygenase enzyme activity was observed in Z. mays roots. The activities of ascorbate-recycling enzymes (dehydroascorbate reductase and monodehydroascorbate reductase) were significantly increased in relation to concentration and duration of Pb2+ treatment. The study concludes that Pb2+-exposure induces ROS-mediated oxidative damage during early period of exposure despite the upregulation of enzymes of ascorbate-glutathione cycle.

  7. Arsenic uptake by arbuscular mycorrhizal maize (Zea mays L.) grown in an arsenic-contaminated soil with added phosphorus

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As)uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment. Non-mycorrhizal and zero-P addition controls were included. Plant biomass and concentrations and uptake of As, P, and other nutrients, AM colonization, root lengths, and hyphal length densities were determined. The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium. Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments, but shoot and root biomass of AM plants was depressed by P application. AM fungal inoculation decreased shoot As concentrations when no P was added, and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition, respectively. Shoot and root uptake of P, Mn, Cu, and Zn increased, but shoot Fe uptake decreased by 44.6%, with inoculation,when P was added. P addition reduced shoot P, Fe, Mn, Cu, and Zn uptake of AM plants, but increased root Fe and Mn uptake of the nonmycorrhizal ones. AM colonization therefore appeared to enhance plant tolerance to As in low P soil, and have some potential for the phytostabilization of As-contaminated soil, however, P application may introduce additional environmental risk by increasing soil As mobility.

  8. The maize (Zea mays ssp. mays var. B73) genome encodes 33 members of the purple acid phosphatase family.

    Science.gov (United States)

    González-Muñoz, Eliécer; Avendaño-Vázquez, Aida-Odette; Montes, Ricardo A Chávez; de Folter, Stefan; Andrés-Hernández, Liliana; Abreu-Goodger, Cei; Sawers, Ruairidh J H

    2015-01-01

    Purple acid phosphatases (PAPs) play an important role in plant phosphorus nutrition, both by liberating phosphorus from organic sources in the soil and by modulating distribution within the plant throughout growth and development. Furthermore, members of the PAP protein family have been implicated in a broader role in plant mineral homeostasis, stress responses and development. We have identified 33 candidate PAP encoding gene models in the maize (Zea mays ssp. mays var. B73) reference genome. The maize Pap family includes a clear single-copy ortholog of the Arabidopsis gene AtPAP26, shown previously to encode both major intracellular and secreted acid phosphatase activities. Certain groups of PAPs present in Arabidopsis, however, are absent in maize, while the maize family contains a number of expansions, including a distinct radiation not present in Arabidopsis. Analysis of RNA-sequencing based transcriptome data revealed accumulation of maize Pap transcripts in multiple plant tissues at multiple stages of development, and increased accumulation of specific transcripts under low phosphorus availability. These data suggest the maize PAP family as a whole to have broad significance throughout the plant life cycle, while highlighting potential functional specialization of individual family members.

  9. Environmental materials for remediation of soils contaminated with lead and cadmium using maize (Zea mays L.) growth as a bioindicator.

    Science.gov (United States)

    Shi, Yu; Huang, Zhanbin; Liu, Xiujie; Imran, Suheryani; Peng, Licheng; Dai, Rongji; Deng, Yulin

    2016-04-01

    Heavy metal pollution is a severe environmental problem. Remediation of contaminated soils can be accomplished using environmental materials that are low cost and environmentally friendly. We evaluated the individual and combination effects of humic acid (HA), super absorbent polymer (SAP), zeolite (ZE), and fly ash composites (FC) on immobilization of lead (Pb) and cadmium (Cd) in contaminated soils. We also investigated long-term practical approaches for remediation of heavy metal pollution in soil. The biochemical and morphological properties of maize (Zea mays L.) were selected as biomarkers to assess the effects of environmental materials on heavy metal immobilization. The results showed that addition of test materials to soil effectively reduced heavy metal accumulation in maize foliage, improving chlorophyll levels, plant growth, and antioxidant enzyme activity. The test materials reduced heavy metal injury to maize throughout the growth period. A synergistic effect from combinations of different materials on immobilization of Pb and Cd was determined based on the reduction of morphological and biochemical injuries to maize. The combination of zeolite and humic acid was especially effective. Treatment with a combination of HA + SAP + ZE + FC was superior for remediation of soils contaminated with high levels of Pb and Cd.

  10. Potassium Management for Improving Growth and Grain Yield of Maize (Zea mays L.) under Moisture Stress Condition

    Science.gov (United States)

    Amanullah; Iqbal, Asif; Irfanullah; Hidayat, Zeeshan

    2016-01-01

    Potassium (K) fertilizer management is beneficial for improving growth, yield and yield components of field crops under moisture stress condition in semiarid climates. Field experiments were conducted to study the response of maize (Zea mays L., cv. Azam) to foliar and soil applied K during summer 2013 and 2014. The experiments were carried out at the Agronomy Research Farm of The University of Agriculture Peshawar, Northwest Pakistan under limited irrigation (moisture stress) condition. It was concluded from the results that application of foliar K at the rate of 1–3% and foliar Zn at the rate of 0.1–0.2% was more beneficial in terms of better growth, higher yield and yield components of maize under moisture stress condition. Early spray (vegetative stage) resulted in better growth and higher yield than late spray (reproductive stage). Soil K treated plots (rest) plots performed better than control (K not applied) in terms of improved growth, higher yield and yield components of maize crop. The results further demonstrated that increasing the rate of soil applied K up to 90 kg P ha−1 in two equal splits (50% each at sowing and knee height) improve growth and maize productivity under semiarid climates. PMID:27694964

  11. Breeding for culinary and nutritional quality of common bean (Phaseolus vulgaris L. in intercropping systems with maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Rodino A.P.

    1999-01-01

    Full Text Available Common bean (Phaseolus vulgaris L. is widely intercropped with maize (Zea mays L. in the North of Spain. Breeding beans for multiple cropping systems is important for the development of a productive and sustainable agriculture, and is mainly oriented to minimize intercrop competition and to stabilize complementarity with maize. Most agricultural research on intercropping to date has focused on the agronomic and overall yield effects of the different species, but characters related with socio-economic and food quality aspects are also important. The effect of intercropping beans with maize on food seed quality traits was studied for thirty-five bush bean varieties under different environments in Galicia (Northwestern Spain. Parameters determining Asturian (Northern Spain white bean commercial and culinary quality have also been evaluated in fifteen accessions. There are significant differences between varieties in the selected cropping systems (sole crop, intercrop with field maize and intercrop with sweet maize for dry and soaked seed weight, coat proportion, crude protein, crude fat and moisture. Different white bean accessions have been chosen according to their culinary quality. Under these environmental conditions it appears that intercropping systems with sweet maize give higher returns than sole cropping system. It is also suggested that the culinary and nutritional quality potential of some white bean accessions could be the base material in a breeding programme the objectives of which are to develop varieties giving seeds with high food quality.

  12. Cloning and expression of the VHDL receptor from fat body of the corn ear worm, Helicoverpa zea.

    Science.gov (United States)

    Persaud, Deryck R; Haunerland, Norbert H

    2004-01-01

    In Noctuids, storage proteins are taken up into fat body by receptor-mediated endocytosis. These include arylphorin and a second, structurally unrelated very high-density lipoprotein (VHDL). Previously, we have isolated a single storage protein receptor from the corn earworm, Helicoverpa zea, which binds both VHDL and arylphorin. The receptor protein is a basic, N-terminally blocked, approximately 80 kDa protein that is associated with fat body membranes. Microsequencing of proteolytic fragments of the isolated receptor protein revealed internal sequences that were used to clone the complete cDNA of the VHDL receptor by 3' and 5' RACE techniques. The receptor protein, when expressed in vitro via a suitable insect expression vector, reacted with antibodies against the native VHDL receptor and bound strongly to its ligand VHDL, thus confirming that the cloned cDNA represents indeed the previously purified VHDL receptor. The receptor protein and a second, similar protein also found associated with the fat body membrane show considerable homology to putative basic juvenile hormone suppressible proteins cloned previously from other Noctuid species. Sequence analysis revealed that the receptor is likely a peripheral membrane protein that may mediate the selective uptake of VHDL.

  13. Cloning and expression of the VHDL receptor from fat body of the corn ear worm, Helicoverpa zea

    Directory of Open Access Journals (Sweden)

    Deryck R. Persaud

    2004-02-01

    Full Text Available In Noctuids, storage proteins are taken up into fat body by receptor-mediated endocytosis. These include arylphorin and a second, structurally unrelated very high-density lipoprotein (VHDL. Previously, we have isolated a single storage protein receptor from the corn earworm, Helicoverpa zea, which binds both VHDL and arylphorin. The receptor protein is a basic, N-terminally blocked, ?80 kDa protein that is associated with fat body membranes. Microsequencing of proteolytic fragments of the isolated receptor protein revealed internal sequences that were used to clone the complete cDNA of the VHDL receptor by 3' and 5' RACE techniques. The receptor protein, when expressed in vitro via a suitable insect expression vector, reacted with antibodies against the native VHDL receptor and bound strongly to its ligand VHDL, thus confirming that the cloned cDNA represents indeed the previously purified VHDL receptor. The receptor protein and a second, similar protein also found associated with the fat body membrane show considerable homology to putative basic juvenile hormone suppressible proteins cloned previously from other Noctuid species. Sequence analysis revealed that the receptor is likely a peripheral membrane protein that may mediate the selective uptake of VHDL.

  14. The effect of triazole induced photosynthetic pigments and biochemical constituents of Zea mays L. (Maize) under drought stress

    Science.gov (United States)

    Rajasekar, Mahalingam; Rabert, Gabriel Amalan; Manivannan, Paramasivam

    2016-06-01

    In this investigation, pot culture experiment was carried out to estimate the ameliorating effect of triazole compounds, namely Triadimefon (TDM), Tebuconazole (TBZ), and Propiconazole (PCZ) on drought stress, photosynthetic pigments, and biochemical constituents of Zea mays L. (Maize). From 30 days after sowing (DAS), the plants were subjected to 4 days interval drought (DID) stress and drought with TDM at 15 mg l-1, TBZ at 10 mg l-1, and PCZ at 15 mg l-1. Irrigation at 1-day interval was kept as control. Irrigation performed on alternative day. The plant samples were collected on 40, 50, and 60 DAS and separated into root, stem, and leaf for estimating the photosynthetic pigments and biochemical constituents. Drought and drought with triazole compounds treatment increased the biochemical glycine betaine content, whereas the protein and the pigments contents chlorophyll-a, chlorophyll-b, total chlorophyll, carotenoid, and anthocyanin decreased when compared to control. The triazole treatment mitigated the adverse effects of drought stress by increasing the biochemical potentials and paved the way to overcome drought stress in corn plant.

  15. Gravitropic reaction of primary seminal roots of Zea mays L. influenced by temperature and soil water potential.

    Science.gov (United States)

    Nakamoto, T

    1995-03-01

    The growth of the primary seminal root of maize (Zea mays L.) is characterized by an initial negative gravitropic reaction and a later positive one that attains a plagiotropic liminal angle. The effects of temperature and water potential of the surrounding soil on these gravitropic reactions were studied. Temperatures of 32, 25, and 18C and soil water potentials of -5, -38, and -67 kPa were imposed and the direction of growth was measured for every 1 cm length of the root. The initial negative gravitropic reaction extended to a distance of about 10 cm from the grain. Higher temperatures reduced the initial negative gravitropic reaction. Lower soil water potential induced a downward growth at root emergence. A mathematical model, in which it was assumed that the rate of the directional change of root growth was a sum of a time-dependent negative gravitropic reaction and an establishment of the liminal angle, adequately fitted the distance-angle relations. It was suggested that higher temperatures and/or a lower water potential accelerated the diminution of the initial negative gravitropic reaction.

  16. Global and grain-specific accumulation of glycoside hydrolase family 10 xylanases in transgenic maize (Zea mays).

    Science.gov (United States)

    Gray, Benjamin N; Bougri, Oleg; Carlson, Alvar R; Meissner, Judy; Pan, Shihao; Parker, Matthew H; Zhang, Dongcheng; Samoylov, Vladimir; Ekborg, Nathan A; Michael Raab, R

    2011-12-01

    In planta expression of cell wall degrading enzymes is a promising approach for developing optimized biomass feedstocks that enable low-cost cellulosic biofuels production. Transgenic plants could serve as either an enzyme source for the hydrolysis of pretreated biomass or as the primary biomass feedstock in an autohydrolysis process. In this study, two xylanase genes, Bacillus sp. NG-27 bsx and Clostridium stercorarium xynB, were expressed in maize (Zea mays) under the control of two different promoters. Severe phenotypic effects were associated with xylanase accumulation in maize, including stunted plants and sterile grains. Global expression of these xylanases from the rice ubiquitin 3 promoter (rubi3) resulted in enzyme accumulation of approximately 0.01 mg enzyme per gram dry weight, or approximately 0.1% of total soluble protein (TSP). Grain-specific expression of these enzymes from the rice glutelin 4 promoter (GluB-4) resulted in higher-level accumulation of active enzyme, with BSX and XynB accumulating up to 4.0% TSP and 16.4% TSP, respectively, in shriveled grains from selected T0 plants. These results demonstrate the potential utility of the GluB-4 promoter for biotechnological applications. The phenotypic effects of xylanase expression in maize presented here demonstrate the difficulties of hemicellulase expression in an important crop for cellulosic biofuels production. Potential alternate approaches to achieve xylanase accumulation in planta without the accompanying negative phenotypes are discussed.

  17. Expression Patterns of Genes Involved in Ascorbate-Glutathione Cycle in Aphid-Infested Maize (Zea mays L.) Seedlings.

    Science.gov (United States)

    Sytykiewicz, Hubert

    2016-02-23

    Reduced forms of ascorbate (AsA) and glutathione (GSH) are among the most important non-enzymatic foliar antioxidants in maize (Zea mays L.). The survey was aimed to evaluate impact of bird cherry-oat aphid (Rhopalosiphum padi L.) or grain aphid (Sitobion avenae F.) herbivory on expression of genes related to ascorbate-glutathione (AsA-GSH) cycle in seedlings of six maize varieties (Ambrozja, Nana, Tasty Sweet, Touran, Waza, Złota Karłowa), differing in resistance to the cereal aphids. Relative expression of sixteen maize genes encoding isoenzymes of ascorbate peroxidase (APX1, APX2, APX3, APX4, APX5, APX6, APX7), monodehydroascorbate reductase (MDHAR1, MDHAR2, MDHAR3, MDHAR4), dehydroascorbate reductase (DHAR1, DHAR2, DHAR3) and glutathione reductase (GR1, GR2) was quantified. Furthermore, effect of hemipterans' attack on activity of APX, MDHAR, DHAR and GR enzymes, and the content of reduced and oxidized ascorbate and glutathione in maize plants were assessed. Seedling leaves of more resistant Z. mays varieties responded higher elevations in abundance of target transcripts. In addition, earlier and stronger aphid-triggered changes in activity of APX, MDHAR, DHAR and GR enzymes, and greater modulations in amount of the analyzed antioxidative metabolites were detected in foliar tissues of highly resistant Ambrozja genotype in relation to susceptible Tasty Sweet plants.

  18. Detection and evolution of resistance to the pyrethroid cypermethrin in Helicoverpa zea (Lepidoptera: Noctuidae) populations in Texas.

    Science.gov (United States)

    Pietrantonio, P V; Junek, T A; Parker, R; Mott, D; Siders, K; Troxclair, N; Vargas-Camplis, J; Westbrook, J K; Vassiliou, V A

    2007-10-01

    The bollworm, Helicoverpa zea (Boddie), is a key pest of cotton in Texas. Bollworm populations are widely controlled with pyrethroid insecticides in cotton and exposed to pyrethroids in other major crops such as grain sorghum, corn, and soybeans. A statewide program that evaluated cypermethrin resistance in male bollworm populations using an adult vial test was conducted from 2003 to 2006 in the major cotton production regions of Texas. Estimated parameters from the most susceptible field population currently available (Burleson County, September 2005) were used to calculate resistance ratios and their statistical significance. Populations from several counties had statistically significant (P Nueces County in 2004, and Williamson and Uvalde Counties in 2005. These findings explain the observed pyrethroid control failures in various counties in Texas. Based on the assumption that resistance is caused by a single gene, the Hardy-Weinberg equilibrium formula was used for estimation of frequencies for the putative resistant allele (q) using 3 and 10 microg/vial as discriminatory dosages for susceptible and heterozygote resistant insects, respectively. The influence of migration on local levels of resistance was estimated by analysis of wind trajectories, which partially clarifies the rapid evolution of resistance to cypermethrin in bollworm populations. This approach could be used in evaluating resistance evolution in other migratory pests.

  19. Improved tolerance of maize (Zea mays L.) to heavy metals by colonization of a dark septate endophyte (DSE) Exophiala pisciphila

    Energy Technology Data Exchange (ETDEWEB)

    Li, T.; Liu, M.J.; Zhang, X.T. [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China); Zhang, H.B. [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China); Department of Biology, Yunnan University, Kunming, 650091 Yunnan (China); Sha, T. [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China); Zhao, Z.W., E-mail: zhaozhw@ynu.edu.cn [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China)

    2011-02-15

    Dark septate endophytes (DSE) are ubiquitous and abundant in stressful environments including heavy metal (HM) stress. However, our knowledge about the roles of DSE in improving HM tolerance of their host plants is poor. In this study, maize (Zea mays L.) was inoculated with a HM tolerant DSE strain Exophiala pisciphila H93 in lead (Pb), zinc (Zn), and cadmium (Cd) contaminated soils. E. pisciphila H93 successfully colonized and formed typical DSE structures in the inoculated maize roots. Colonization of E. pisciphila H93 alleviated the deleterious effects of excessive HM supplements and promoted the growth of maize (roots and shoots) under HM stress conditions, though it significantly decreased the biomass of inoculated maize under no HM stress. Further analysis showed that the colonization of E. pisciphila H93 improved the tolerance of maize to HM by restricting the translocation of HM ions from roots to shoots. This study demonstrated that under higher HM stress, such a mutual symbiosis between E. pisciphila and its host (maize) may be an efficient strategy to survive in the stressful environments. - Research Highlights: {yields}Effect of DSE (E. pisciphila) on heavy metal tolerance of maize host was studied. {yields}DSE alleviated the deleterious effect of excessive heavy metals on maize. {yields}DSE restricted the transfer of heavy metals from the roots to shoots in maize. {yields}DSE colonization improved the tolerance of their host plants to heavy metals.

  20. Improved tolerance of maize (Zea mays L.) to heavy metals by colonization of a dark septate endophyte (DSE) Exophiala pisciphila.

    Science.gov (United States)

    Li, T; Liu, M J; Zhang, X T; Zhang, H B; Sha, T; Zhao, Z W

    2011-02-15

    Dark septate endophytes (DSE) are ubiquitous and abundant in stressful environments including heavy metal (HM) stress. However, our knowledge about the roles of DSE in improving HM tolerance of their host plants is poor. In this study, maize (Zea mays L.) was inoculated with a HM tolerant DSE strain Exophiala pisciphila H93 in lead (Pb), zinc (Zn), and cadmium (Cd) contaminated soils. E. pisciphila H93 successfully colonized and formed typical DSE structures in the inoculated maize roots. Colonization of E. pisciphila H93 alleviated the deleterious effects of excessive HM supplements and promoted the growth of maize (roots and shoots) under HM stress conditions, though it significantly decreased the biomass of inoculated maize under no HM stress. Further analysis showed that the colonization of E. pisciphila H93 improved the tolerance of maize to HM by restricting the translocation of HM ions from roots to shoots. This study demonstrated that under higher HM stress, such a mutual symbiosis between E. pisciphila and its host (maize) may be an efficient strategy to survive in the stressful environments.

  1. Brush border membrane binding properties of Bacillus thuringiensis Vip3A toxin to Heliothis virescens and Helicoverpa zea midguts.

    Science.gov (United States)

    Lee, Mi Kyong; Miles, Paul; Chen, Jeng-Shong

    2006-01-27

    The binding properties of Vip3A, a new family of Bacillus thuringiensis insecticidal toxins, have been examined in the major cotton pests, Heliothis virescens and Helicoverpa zea. Vip3A bound specifically to brush border membrane vesicles (BBMV) prepared from both insect larval midguts. In order to examine the cross-resistance potential of Vip3A to the commercially available Cry1Ac and Cry2Ab2 toxins, the membrane binding site relationship among these toxins was investigated. Competition binding assays demonstrated that Vip3A does not inhibit the binding of either Cry1Ac or Cry2Ab2 and vice versa. BBMV protein blotting experiments showed that Vip3A does not bind to the known Cry1Ac receptors. These distinct binding properties and the unique protein sequence of Vip3A support its use as a novel insecticidal agent. This study indicates a very low cross-resistance potential between Vip3A and currently deployed Cry toxins and hence supports its use in an effective resistance management strategy in cotton.

  2. Allelopathic evaluation of ethanol extracts of Copaifera sabulicola on the initial development of Lactuca sativa, Lycopersicum esculentum, and Zea mays

    Directory of Open Access Journals (Sweden)

    Manoel Viana Linhares Neto

    2014-09-01

    Full Text Available This paper aimed to evaluate the allelopathic potential of ethanol extracts from stem and leaves of Copaifera sabulicola on seed germination and seedling growth of Lactuca sativa and Lycopersicum esculentum, as well as to evaluate the allelopathic effect of these extracts on seedling germination and growth of Zea mays, through bioassays under laboratory conditions. The extracts were tested at the concentrations 0, 250, 500, and 1,000 mg.L-1. We evaluated the germination percentage, germination average speed, germination speed index, and seedling average length. All parameters underwent variance analysis, and the mean values were compared by means of Scott-nott test p 0.05. We found out that, in L. sativa, the extract from stem promoted signicant stimuli on germination percentage and root growth, while the extract from leaves only stimulated root growth. In L. esculentum, the extract from stem promoted signicant stimulus on hypocotyl and root growth, in turn, the extract from leaves stimulated only root growth. In Z. mays, both extracts signicantly inhibited germination. Therefore, we found out the allelopathic potential of ethanol extracts of C. sabulicola on L. sativa and L. esculentum, as well as inhibitory allelopathic effect on Z. mays.

  3. Unraveling the role of dark septate endophyte (DSE) colonizing maize (Zea mays) under cadmium stress: physiological, cytological and genic aspects

    Science.gov (United States)

    Wang, Jun-ling; Li, Tao; Liu, Gao-yuan; Smith, Joshua M.; Zhao, Zhi-wei

    2016-01-01

    A growing body of evidence suggests that plant root-associated fungi such as dark septate endophytes (DSE) can help plants overcome many biotic and abiotic stresses, of great interest is DSE-plant metal tolerance and alleviation capabilities on contaminated soils. However, the tolerance and alleviation mechanisms involved have not yet been elucidated. In the current study, the regulation and physiological response of Zea mays to its root-associated DSE, Exophiala pisciphila was analyzed under increased soil Cd stress (0, 10, 50, 100 mg kg−1). Under Cd stress, DSE inoculation significantly enhanced the activities of antioxidant enzymes and low-molecular weight antioxidants, while also inducing increased Cd accumulation in the cell wall and conversion of Cd into inactive forms by shoot and root specific regulation of genes related to metal uptake, translocation and chelation. Our results showed that DSE colonization resulted in a marked tolerance to Cd, with a significant decrease in cadmium phytotoxicity and a significant increase in maize growth by triggering antioxidant systems, altering metal chemical forms into inactive Cd, and repartitioning subcellular Cd into the cell wall. These results provide comprehensive evidence for the mechanisms by which DSE colonization bioaugments Cd tolerance in maize at physiological, cytological and molecular levels. PMID:26911444

  4. Interactions between Fusarium verticillioides, Ustilago maydis, and Zea mays: an endophyte, a pathogen, and their shared plant host.

    Science.gov (United States)

    Rodriguez Estrada, Alma E; Jonkers, Wilfried; Kistler, H Corby; May, Georgiana

    2012-07-01

    Highly diverse communities of microbial symbionts occupy eukaryotic organisms, including plants. While many well-studied symbionts may be characterized as either parasites or as mutualists, the prevalent but cryptic endophytic fungi are less easily qualified because they do not cause observable symptoms of their presence within their host. Here, we investigate the interactions of an endophytic fungus, Fusarium verticillioides with a pathogen, Ustilago maydis, as they occur within maize (Zea mays). We used experimental inoculations to evaluate metabolic mechanisms by which these three organisms might interact. We assessed the impacts of fungal-fungal interactions on endophyte and pathogen growth within the plant, and on plant growth. We find that F. verticillioides modulates the growth of U. maydis and thus decreases the pathogen's aggressiveness toward the plant. With co-inoculation of the endophyte with the pathogen, plant growth is similar to that which would be gained without the pathogen present. However, the endophyte may also break down plant compounds that limit U. maydis growth, and obtains a growth benefit from the presence of the pathogen. Thus, an endophyte such as F. verticillioides may function as both a defensive mutualist and a parasite, and express nutritional modes that depend on ecological context.

  5. Phosphorus and compost management influence maize (Zea mays productivity under semiarid condition with and without phosphate solubilizing bacteria

    Directory of Open Access Journals (Sweden)

    Amanullah eAmanullah

    2015-12-01

    Full Text Available Phosphorus (P unavailability and lack of organic matter in the soils under semiarid climates are the two major constraints for low crop productivity. Field trial was conducted to study the effects of P levels, compost application times and seed inoculation with phosphate solubilizing bacteria (PSB on the yield and yield components of maize (Zea mays L., cv. Azam. The experiment was conducted at the Agronomy Research Farm of The University of Agriculture Peshawar-Pakistan during summer 2014. The experiment was laid out in randomized complete block design with split plot arrangement using three replications. The two PSB levels [(1 inoculated seed with PSB (+ and (2 seed not inoculated with PSB (- or control] and three compost application times [(30, 15 and 0 days before sowing (DBS] combination (six treatments were used as main plot factor, while four P levels (25, 50, 75 and 100 kg P ha-1 used as subplot factor. The results confirmed that compost applied at sowing time and P applied at the two higher rates (75 and 100 kg P ha-1 had significantly increased yield and yield components of maize under semiarid condition. Maize seed inoculated with PSB (+ had tremendously increased yield and yield components of maize over PSB-control plots (- under semiarid condition.

  6. A two-dimensional microscale model of gas exchange during photosynthesis in maize (Zea mays L.) leaves.

    Science.gov (United States)

    Retta, Moges; Ho, Quang Tri; Yin, Xinyou; Verboven, Pieter; Berghuijs, Herman N C; Struik, Paul C; Nicolaï, Bart M

    2016-05-01

    CO2 exchange in leaves of maize (Zea mays L.) was examined using a microscale model of combined gas diffusion and C4 photosynthesis kinetics at the leaf tissue level. Based on a generalized scheme of photosynthesis in NADP-malic enzyme type C4 plants, the model accounted for CO2 diffusion in a leaf tissue, CO2 hydration and assimilation in mesophyll cells, CO2 release from decarboxylation of C4 acids, CO2 fixation in bundle sheath cells and CO2 retro-diffusion from bundle sheath cells. The transport equations were solved over a realistic 2-D geometry of the Kranz anatomy obtained from light microscopy images. The predicted responses of photosynthesis rate to changes in ambient CO2 and irradiance compared well with those obtained from gas exchange measurements. A sensitivity analysis showed that the CO2 permeability of the mesophyll-bundle sheath and airspace-mesophyll interfaces strongly affected the rate of photosynthesis and bundle sheath conductance. Carbonic anhydrase influenced the rate of photosynthesis, especially at low intercellular CO2 levels. In addition, the suberin layer at the exposed surface of the bundle sheath cells was found beneficial in reducing the retro-diffusion. The model may serve as a tool to investigate CO2 diffusion further in relation to the Kranz anatomy in C4 plants.

  7. INFLUENCE OF FUNGI OF THE GENUS TRICHODERMA ON PHYTOAVAILABILITY CADMIUM AND PHYSIOLOGICAL CONDITION OF MAIZE (ZEA MAYS

    Directory of Open Access Journals (Sweden)

    Magdalena Marchel

    2015-02-01

    Full Text Available The aim of conducted research was to determine in what degree inoculation of soil by fungi Trichoderma modifies process of phytoavailability of cadmium through roots and above ground parts of maize (Zea mays and how it affects cadmium activity as damaging factor of photosynthetic apparatus of plants. Outline of vase experiment covered 5 objects (control without addition of cadmium and 4 objects with increasing amount of cadmium in amount from 10 to 80 mg.kg-1 d.m. soil, and within each object two variants: soil without (-T and with (+T addition of fungi of Trichoderma (+T in shape of granulated preparation of Trianum–G in amount of 750 g.m-3 soil. Increasing amount of cadmium in surface caused decrease of harvest size of roots and above ground parts of maize, but inoculation of surface by Trichoderma fungi softened those changes. Amount of cadmium in plants was increasing promotionally to increasing amount of that metal in soil, but the presence of fungi of Trichoderma type caused decrease of phytoavailability cadmium by above ground parts of maize. Decrease parameters of chlorophyll fluorescence F0, FM, Fv, Fv/FM Fv/F0 showed lack of disturbances in photosynthetic apparatus of maize despite decrease the amount of chlorophyll in leaves under the influence of inserted cadmium doses to soil.

  8. Study of effects of Bt maize (Zea mays) events on Lepidoptera Ostrinia nubilalis, Sesamia nonagrioidesin southwestern France.

    Science.gov (United States)

    Folcher, L; Eychenne, N; Weissenberger, A; Jarry, M; Regnault-Roger, C; Delos, M

    2006-01-01

    Crops of maize (Zea mays L.) were conducted in southwestern France with GMO (Genetic Modified Organism) vs isogenetic varieties in order to verify the control of European Corn Borer (ECB) Ostrinia nubilalis (Hübner) and the Corn Stalk Borer (CBS) Sesamia nonagrioides (Lefevbre) by GMO in field conditions. The bioassays were carried out in 1998 and 1999 before moratorium, then in 2005. Experiments involved respectively 18, 12 and 19 fields cultivated with Furio/Furio cb (GMO), Cecilia/ Elgina (GMO) and PR33P66/PR33P67 (GMO) varieties. These transgenic events expressed Cry1A(b) protein (Bt maize). Plants were noted for insect infestation assessment (number of larvae in stalks and ears per plant). Statistical tests used t-test on couple of plots. Results showed a significant difference in the density of both ECB and CBS between control and the two transgenic events. The two transgenic events acted differently. The control of the two Bt events on the two pests were differentiated and discussed. These experiments underlined the importance of field evaluation for testing real effects of transgenic events on crop according the environmental context.

  9. Potassium Management for Improving Growth and Grain Yield of Maize (Zea mays L.) under Moisture Stress Condition.

    Science.gov (United States)

    Amanullah; Iqbal, Asif; Irfanullah; Hidayat, Zeeshan

    2016-10-03

    Potassium (K) fertilizer management is beneficial for improving growth, yield and yield components of field crops under moisture stress condition in semiarid climates. Field experiments were conducted to study the response of maize (Zea mays L., cv. Azam) to foliar and soil applied K during summer 2013 and 2014. The experiments were carried out at the Agronomy Research Farm of The University of Agriculture Peshawar, Northwest Pakistan under limited irrigation (moisture stress) condition. It was concluded from the results that application of foliar K at the rate of 1-3% and foliar Zn at the rate of 0.1-0.2% was more beneficial in terms of better growth, higher yield and yield components of maize under moisture stress condition. Early spray (vegetative stage) resulted in better growth and higher yield than late spray (reproductive stage). Soil K treated plots (rest) plots performed better than control (K not applied) in terms of improved growth, higher yield and yield components of maize crop. The results further demonstrated that increasing the rate of soil applied K up to 90 kg P ha(-1) in two equal splits (50% each at sowing and knee height) improve growth and maize productivity under semiarid climates.

  10. Weed Control and Corn (Zea mays Response to Planting Pattern and Herbicide Program with High Seeding Rates in North Carolina

    Directory of Open Access Journals (Sweden)

    Mitchell K. Williams

    2014-01-01

    Full Text Available Effective weed control in corn (Zea mays L. is important to optimize yield. Concern over environmental impact of atrazine and selection for glyphosate resistance has increased the need to develop alternative strategies that use herbicides other than atrazine and glyphosate and appropriate cultural practices to control weeds. Research was conducted during 2011 and 2012 to determine weed and corn response to herbicide programs containing dicamba, glufosinate, and glyphosate applied postemergence alone or with atrazine in single- and twin-row planting patterns. Planting pattern had no effect on common ragweed (Ambrosia artemisiifolia L. and Texas panicum (Panicum texanum L. population and did not interact with herbicide program. Effective weed control hastened maturity in some but not all instances. Under weed-free conditions, corn grain yield was higher in 5 of 7 trials when planted in twin rows versus single rows at equivalent corn populations (141,000 plants ha−1. These results suggest that while planting pattern may not impact weed control dramatically, planting corn in twin rows may be an effective alternative to single-row planting patterns because of increased yield under high corn populations.

  11. Unraveling the role of dark septate endophyte (DSE) colonizing maize (Zea mays) under cadmium stress: physiological, cytological and genic aspects.

    Science.gov (United States)

    Wang, Jun-ling; Li, Tao; Liu, Gao-yuan; Smith, Joshua M; Zhao, Zhi-wei

    2016-02-25

    A growing body of evidence suggests that plant root-associated fungi such as dark septate endophytes (DSE) can help plants overcome many biotic and abiotic stresses, of great interest is DSE-plant metal tolerance and alleviation capabilities on contaminated soils. However, the tolerance and alleviation mechanisms involved have not yet been elucidated. In the current study, the regulation and physiological response of Zea mays to its root-associated DSE, Exophiala pisciphila was analyzed under increased soil Cd stress (0, 10, 50, 100 mg kg(-1)). Under Cd stress, DSE inoculation significantly enhanced the activities of antioxidant enzymes and low-molecular weight antioxidants, while also inducing increased Cd accumulation in the cell wall and conversion of Cd into inactive forms by shoot and root specific regulation of genes related to metal uptake, translocation and chelation. Our results showed that DSE colonization resulted in a marked tolerance to Cd, with a significant decrease in cadmium phytotoxicity and a significant increase in maize growth by triggering antioxidant systems, altering metal chemical forms into inactive Cd, and repartitioning subcellular Cd into the cell wall. These results provide comprehensive evidence for the mechanisms by which DSE colonization bioaugments Cd tolerance in maize at physiological, cytological and molecular levels.

  12. The maize (Zea mays ssp. mays var. B73 genome encodes 33 members of the purple acid phosphatase gene family

    Directory of Open Access Journals (Sweden)

    Eliécer eGonzález Muñoz

    2015-05-01

    Full Text Available Purple acid phosphatases (PAPs play an important role in plant phosphorus nutrition, both by liberating phosphorus from organic sources in the soil and by modulating distribution within the plant throughout growth and development. Furthermore, members of the PAP protein family have been implicated in a broader role in plant mineral homeostasis, stress responses and development. We have identified 33 candidate PAP encoding gene models in the maize (Zea mays ssp. mays var. B73 reference genome. The maize Pap family includes a clear single-copy ortholog of the Arabidopsis gene AtPAP26, shown previously to encode both major intracellular and secreted acid phosphatase activities. Certain groups of PAPs present in Arabidopsis, however, are absent in maize, while the maize family contains a number of expansions, including a distinct radiation not present in Arabidopsis. Analysis of RNA-sequencing based transcriptome data revealed accumulation of maize Pap transcripts in multiple plant tissues at multiple stages of development, and increased accumulation of specific transcripts under low phosphorus availability. These data suggest the maize PAP family as a whole to have broad significance throughout the plant life cycle, while highlighting potential functional specialization of individual family members.

  13. Characterization of ApB73, a virulence factor important for colonization of Zea mays by the smut Ustilago maydis.

    Science.gov (United States)

    Stirnberg, Alexandra; Djamei, Armin

    2016-12-01

    The biotrophic fungus Ustilago maydis, the causal agent of corn smut disease, uses numerous small secreted effector proteins to suppress plant defence responses and reshape the host metabolism. However, the role of specific effectors remains poorly understood. Here, we describe the identification of ApB73 (Apathogenic in B73), an as yet uncharacterized protein essential for the successful colonization of maize by U. maydis. We show that apB73 is transcriptionally induced during the biotrophic stages of the fungal life cycle. The deletion of the apB73 gene results in cultivar-specific loss of gall formation in the host. The ApB73 protein is conserved among closely related smut fungi. However, using virulence assays, we show that only the orthologue of the maize-infecting head smut Sporisorium reilianum can complement the mutant phenotype of U. maydis. Although microscopy shows that ApB73 is secreted into the biotrophic interface, it seems to remain associated with fungal cell wall components or the fungal plasma membrane. Taken together, the results show that ApB73 is a conserved and important virulence factor of U. maydis that localizes to the interface between the pathogen and its host Zea mays.

  14. Potential of kenaf (Hibiscus cannabinus L.) and corn (Zea mays L.) for phytoremediation of dredging sludge contaminated by trace metals.

    Science.gov (United States)

    Arbaoui, Sarra; Evlard, Aricia; Mhamdi, Mohamed El Wafi; Campanella, Bruno; Paul, Roger; Bettaieb, Taoufik

    2013-07-01

    The potential of kenaf (Hibiscus cannabinus L.) and corn (Zea mays L.) for accumulation of cadmium and zinc was investigated. Plants have been grown in lysimetres containing dredging sludge, a substratum naturally rich in trace metals. Biomass production was determined. Sludge and water percolating from lysimeters were analyzed by atomic absorption spectrometry. No visible symptoms of toxicity were observed during the three- month culture. Kenaf and corn tolerate trace metals content in sludge. Results showed that Zn and Cd were found in corn and kenaf shoots at different levels, 2.49 mg/kg of Cd and 82.5 mg/kg of Zn in kenaf shoots and 2.1 mg/kg of Cd and 10.19 mg/kg in corn shoots. Quantities of extracted trace metals showed that decontamination of Zn and Cd polluted substrates is possible by corn and kenaf crops. Tolerance and bioaccumulation factors indicated that both species could be used in phytoremediation.

  15. Molecular evolution and gene expression differences within the HD-Zip transcription factor family of Zea mays L.

    Science.gov (United States)

    Mao, Hude; Yu, Lijuan; Li, Zhanjie; Liu, Hui; Han, Ran

    2016-04-01

    Homeodomain-leucine zipper (HD-Zip) transcription factors regulate developmental processes and stress responses in plants, and they vary widely in gene number and family structure. In this study, 55 predicted maize HD-Zip genes were systematically analyzed with respect to their phylogenetic relationships, molecular evolution, and gene expression in order to understand the functional diversification within the family. Phylogenetic analysis of HD-Zip proteins from Zea mays, Oryza sativa, Arabidopsis thaliana, Vitis vinifera, and Physcomitrella patens showed that they group into four classes. We inferred that the copy numbers of classes I and III genes were relatively conserved in all five species. The 55 maize HD-Zip genes are distributed randomly on the ten chromosomes, with 15 segmental duplication and 4 tandem duplication events, suggesting that segmental duplications were the major contributors in the expansion of the maize HD-Zip gene family. Expression analysis of the 55 maize HD-Zip genes in different tissues and drought conditions revealed differences in the expression levels and patterns between the four classes. Promoter analysis revealed that a number of stress response-, hormone response-, light response-, and development-related cis-acting elements were present in their promoters. Our results provide novel insights into the molecular evolution and gene expression within the HD-Zip gene family in maize, and provide a solid foundation for future functional study of the HD-Zip genes in maize.

  16. Agrobacterium-mediated transformation of maize (Zea mays) with Cre-lox site specific recombination cassettes in BIBAC vectors.

    Science.gov (United States)

    Vega, Juan M; Yu, Weichang; Han, Fangpu; Kato, Akio; Peters, Eric M; Zhang, Zhanyuan J; Birchler, James A

    2008-04-01

    The Cre/loxP site-specific recombination system has been applied in various plant species including maize (Zea mays) for marker gene removal, gene targeting, and functional genomics. A BIBAC vector system was adapted for maize transformation with a large fragment of genetic material including a herbicide resistance marker gene, a 30 kb yeast genomic fragment as a marker for fluorescence in situ hybridization (FISH), and a 35S-lox-cre recombination cassette. Seventy-five transgenic lines were generated from Agrobacterium-mediated transformation of a maize Hi II line with multiple B chromosomes. Eighty-four inserts have been localized among all 10 A chromosome pairs by FISH using the yeast DNA probe together with a karyotyping cocktail. No inserts were found on the B chromosomes; thus a bias against the B chromosomes by the Agrobacterium-mediated transformation was revealed. The expression of a cre gene was confirmed in 68 of the 75 transgenic lines by a reporter construct for cre/lox mediated recombination. The placement of the cre/lox site-specific recombination system in many locations in the maize genome will be valuable materials for gene targeting and chromosome engineering.

  17. 玉米苞叶中新黄酮类化合物的分离和鉴定%Isolation and Identification of Novel Flavonoids from the Bract of Zea mays L

    Institute of Scientific and Technical Information of China (English)

    张沐新; 刘银燕; 孙薇; 杨晓虹; 王广树

    2011-01-01

    从玉米(Zea maysL)苞叶乙醇提取物中分离得到了4个黄酮类化合物,采用UV,IR,MS,1D NMR和2D NMR方法对化合物的结构进行了鉴定,它们分别为苜蓿素(1)、苜蓿素-5-O-β-D-吡喃葡萄糖苷(2)、苜蓿素-7-O-β-D-吡喃葡萄糖苷(3)和苜蓿素-7-O-[β-D-呋喃芹糖基-(1-2)]β-D-吡喃葡萄糖苷(4).其中,化合物4为新化合物,化合物1~3为首次从该植物中分离得到.%Zea mays ( maize) , a member of the Poaceae, is the most economically important crop in China,about 24 million hectares of Zea mays has been cultivated each year in China, there is about 600 kg of the bract of Zea mays per hectare, and thus the resources of the bract of Zea mays is extremely rich. Although there are some pharmacological activity researches about radical scavenging activity against hydroxyl radical and superoxide anion radical, reducing blood lipid and inhibiting arteriosclerosis, the studies on phytochemical constituents of the bract of Zea mays have not been reported. In order to utilize the resources of the bract ofZea mays, we investigated the chemical constituents of the bract of Zea mays. The air-dried bract ol Zea mays was extracted with 95% ethanol at room temperature, the extract was subjected to Diaion AB-8 column chro-matography eluated with ethanol-H2O, and the eluate was further chromatographed on silica gel and Sephadex LH-20 columns repeatedly to yield 4 flavonoid compounds. Their structures were identified as tricin( 1) , tricin 5-0-β-D-glucopyranoside(2) , tricin 7-O-/M>-glucopyranoside(3) , tricin 7-0-[β-D-apifuranosyl( 1-+2) ]-β-D-glucopyranoside(4) by spectral analysis(UV, IR, MS and ID, 2D NMR) , respectively. Among them, compound 4 is a new flavonoid compound, compounds 1, 2 and 3 are firstly isolated from this plant.

  18. 玉蜀黍叶中氨基酸及无机元素的含量测定%Determination of Amino Acids and Inorganic Elements in the leaves of Zea mays L.

    Institute of Scientific and Technical Information of China (English)

    刘银燕; 杨晓虹; 陈滴; 王文娜; 孙琦; 杨锦竹

    2012-01-01

    对玉蜀黍叶中氨基酸和无机元素进行研究.采用日立835-50型氨基酸分析仪和ICP - AES法对玉蜀黍叶中氨基酸和无机元素进行了研究.结果表明,玉蜀黍叶中含有17种氨基酸和12种人体必需的无机元素.本研究为玉蜀黍叶的药用开发提供了参考依据.%To determine amino acids and inorganic elements in the leaves of zea mays L., amino acids in leaves of zea mays L. Were determined by the amino acid analyzer, and inorganic elements in leaves of zea mays L. Were determined by ICP-AES. The result showed thai there were 17 amino acids and 12 kind of inorganic elements in leaves of zea mays L., and it provide a basis for the medical exploitation oi the leaves of zea mays L..

  19. Impacto psicosocial del Downsizing sobre los trabajadores

    Directory of Open Access Journals (Sweden)

    CRISTÓBAL JIMÉNEZ JIMÉNEZ

    2006-01-01

    Full Text Available El presente trabajo intenta ahondar en lo expuesto en un trabajo anterior sobre el downsizing como fenómeno psicosociolaboral, analizando su impacto psicosocial. En primer lugar, se exponen los diferentes niveles de comprensión de este fenómeno, para pasar al análisis de los efectos y consecuencias sobre las personas, diferenciando entre dos tipos de víctimas: a los que se van de la organización (despedidos y b los que se quedan en la organización (supervivientes, prestando especial atención a lo que se conoce ya como el "síndrome del superviviente", para lo que se aporta información sobre sus características, las variables moderadoras que intervienen y los modelos explicativos del mismo. Se termina con algunas consideraciones sobre la actualidad y relevancia de dicho síndrome sugiriendo la idea de que el fenómeno del downsizing y sus consecuencias sobre las personas nos enfrenta a lo que podríamos ya considerar como un nuevo síndrome de la Psicopatología Laboral: el síndrome del superviviente.

  20. DISERTACIÓN SOBRE JUSTICIA Y EQUIDAD

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    Sayuri P. Tamura M.

    2001-01-01

    Full Text Available «Disertación sobre equidad y justicia» es básicamente una respuesta a una inquietud en particular que yo tenía sobre las distintas posiciones que existen sobre estos dos temas y cómo definir cuál es la más acertada. Hice una descripción del punto de vista de Amartya Sen –la violación de los derechos sobre la propiedad privada es justificable si evitan las hambrunas2– frente al de Robert Nozick –la propiedad privada es un derecho fundamental y como tal debe ser respetado3–, sin embargo, aunque ambos enfoques son totalmente contrarios tienen mucho sentido, por lo cual es bastante difícil decidirse por uno en particular. Fue de esta forma, enfrentando sus opiniones, que yo logré desarrollar una posición frente a estas dos perspectivas, y así dar mi opinión al DISERTACIÓN SOBRE JUSTICIA Y EQUIDAD SAYURI P. TAMURA M. Estudiante de Economía y Negocios Internacionales de la Universidad ICESI. respecto. Al final, llegué a una conclusión, que aunque no es la más original y tampoco es la única, tiene mucho sentido y seguramente de ser posible, la situación del país podría cambiar para bien.

  1. Técnica de amostragem para comparar o dano causado pela lagarta-da-espiga, Heliothis zea (Boddie, em cultivares de milho Sampling techniques to compare the damage by Heliothis zea (Boddie in corn varieties

    Directory of Open Access Journals (Sweden)

    Violeta Nagai

    1986-01-01

    Full Text Available Neste trabalho, realizado no Instituto Agronômico, determinou-se o tamanho da amostra para estudos de danos causados pela lagarta-da-espiga, Heliothis zea (Boddie, avaliados pelo método de Widstrom. Foram utilizados dados de dois experimentos de campo, com um cultivar resistente (Asteca Prolífico VRPE VII, um suscetível (híbrido duplo IAC Hmd 7974, o 'Maya XVI' e o híbrido simples HS 7777, em 1978/79 e 1979/80. O critério para estimar o tamanho da amostra foi de que esse tamanho permitisse detectar uma diferença de 10 ou de 20% da média geral entre médias de danos, em cultivares de milho, e avaliar o dano médio por cultivar com erro-padrão de 10 ou de 20% da média. Para definir o processo de amostragem, utilizou-se o método de componentes de variância, estimados a partir de dois modelos matemáticos. O tamanho da amostra foi bastante variável entre cultivares, sendo maior no resistente. Entre os possíveis tamanhos mínimos de amostra para detectar uma diferença de 10% da média geral entre médias de danos de tratamentos, podem ser utilizados seis blocos com quatro linhas de 24 plantas; para uma diferença de 20% de média, cinco blocos com três linhas de seis plantas são suficientes. Para estimar a média de danos por cultivar, com erro-padrão de 10% de média, são necessários sete blocos com quatro linhas de 30 plantas, no cultivar Asteca, e cinco blocos com duas linhas de 24 plantas nos cultivares Hmd 7974, HS 7777 e Maya e, com erro-padrão de 20% de média, cinco blocos de três linhas com doze plantas, no 'Asteca', e cinco blocos com duas linhas de seis plantas nos demais cultivares.A study was made to determine the sample size for research on corn resistance to corn ear worm Heliothis zea (Boddie. The damage was measured using the Widstrom centimeter scale. The criteria used to select the sample sizes were such that a difference between two treatments of ten percent or twenty percent of the overall mean should be

  2. Sobre la sublimación

    OpenAIRE

    2007-01-01

    Este documento presenta un trabajo de investigación realizado sobre un concepto clave para la producción teórica y la enseñanza en psicología, como es la noción de sublimación. La investigación indaga la sublimación en el marco de la teoría psicoanalítica, con el objeto de profundizar su explicación conceptual y decidir sobre la pertinencia de tomarlo como noción clave para explicar la producción social del saber.

  3. Principios sobre semáforos

    OpenAIRE

    Valencia Alaix, Víctor Gabriel

    2000-01-01

    Debido a la ausencia de una publicación que reuniese los aspectos más relevantes sobre semáforos y en el marco académico sobre ingeniería de tránsito de los cursos de pregrado y posgrado en Vías y Transporte de la Universidad Nacional de Colombia - Sede Medellín, se ha preparado este documento como guía introductoria a dicho tema. En su preparación se han recogido los tópicos principales de varias publicaciones internacionales y nacionales, además, su desarrollo ha considerado la experi...

  4. Debate sobre estudios postcoloniales y subalternos

    OpenAIRE

    David Morris; McLean, Ian S.; Hillel Eyal; Ivette Hernández; Richard W. Slata; Betsy Campisi; Jackson, Robert H; William Patterson; Kathryn Lehman; Chad Black; Michelle Molina; Ann Twinam; Dennis Hidalgo

    2001-01-01

    A partir de los comentarios a la reseña elaborada por Ian S. Mclean sobre el libro: Cuerpos incas y el cuerpo de Cristo. El Corpus Christi en Cuzco colonial, Perú, escrito por Carolyn Dean, surge un debate sobre los Estudios Postcoloniales y Subalternos, que se desarrolló entre el 12 de agosto y el 3 de septiembre de 2001, a través de la lista de correo electrónico de H-Latam, grupo de discusión dedicado a la historia latinoamericana. En él participaron destacados especial...

  5. Jose carlos mariategui: sus articulos sobre arte

    OpenAIRE

    Henríquez, Cecilia

    2014-01-01

    En la prolífica obra que colma la corta vida del pensador latinoamericano,se encuentran profundas reflexiones sobre el arte que valela pena recordar en e1 año del centenario de su nacimiento. Los juiciosque propone sobre el arte están n1ediados por su pensamiento marxista.Aunque gran conocedor del arte de sus contemporáneos, sucompromiso socialista, cada vez mayor, reduce el espacio del análisisestilístico.Un punto de partida para observar el pensamiento estético deJosé Carlos Mariátegui es s...

  6. Impacto psicosocial del Downsizing sobre los trabajadores

    OpenAIRE

    CRISTÓBAL JIMÉNEZ JIMÉNEZ; JOSÉ LUIS SÁNCHEZ LAGUNA

    2006-01-01

    El presente trabajo intenta ahondar en lo expuesto en un trabajo anterior sobre el downsizing como fenómeno psicosociolaboral, analizando su impacto psicosocial. En primer lugar, se exponen los diferentes niveles de comprensión de este fenómeno, para pasar al análisis de los efectos y consecuencias sobre las personas, diferenciando entre dos tipos de víctimas: a) los que se van de la organización (despedidos) y b) los que se quedan en la organización (supervivientes), prestando especial atenc...

  7. Consideraciones sobre los ensayos de laboratorio

    Directory of Open Access Journals (Sweden)

    José Gabriel Gómez Cortés

    2013-12-01

    Full Text Available Texto de la conferencia dictada por el autor en el Instituto de la Construcción y del Cemento en Madrid. Eduardo Torroja, España, como asistente al IX Curso de Estudios Mayores de la Construcción sobre "LA EDIFICACION Y SU PATOLOGÍA". Se analizan aspectos sobre: los criterios para solicitar ensayos, muestreo, variabilidad de resultados y reproducibilidad de ensayos, criterios de aceptación e importancia de la retroalimentación.

  8. Generalidades sobre el 68 en la narrativa

    OpenAIRE

    Ocampo, Aurora M.

    2013-01-01

    Es mucho lo que se ha escrito sobre el movimiento estudiantil de 1968, según mis registros, cerca de un centenar de libros, además de innumerables artículos, ensayos, narraciones, poemas, teatro y reseñas a los libros como a los grandes ensayos, aparecidos en publicaciones periódicas. Por otro lado, muchos de los libros, ya sean testimoniales, de reflexión sobre lo sucedido, antologías de poesías, ensayos, cuentos, teatro y narrativa en general se han reeditado varias veces; ahora, con motivo...

  9. Milk line as an indicator of the harvesting time of three hybrid seeds of corn (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Célio Trzeciak dos Santos

    2005-03-01

    Full Text Available The experiment was carried out to evaluate the time for harvesting seeds of three hybrids of corn (Zea mays L. at their best physiological quality and the use of the milk line as an indicator of the physiological seed maturity. Single hybrids CD 1723 and CD 5501 and double hybrid OC 705 seeds were collected for 59 days, every four days, starting 23 days after female flowering. Seed dry weight, moisture content, germination, vigour (cold and accelerated aging tests, black layer formation and seed milk line development were analysed. The harvesting time started 47 days after female flowering with high physiological quality of the seeds identified by a joint analysis of those seven characteristics of them. The milk line at stage 4 proved to be the best indicator of the time to harvest corn seeds for maximum physiological quality, because different stages of milk line development in corn seeds could be easily identified in the filed without any special equipment.O experimento foi conduzido durante o ano agrícola de 1996/97 em área experimental da Cooperativa de Desenvolvimento Econômico e Tecnológico (Coodetec, em Cascavel, Paraná, com o objetivo de avaliar o efeito da época de colheita de três híbridos de milho (Zea mays L. na qualidade fisiológica das sementes e o uso da linha de solidificação do endosperma como indicativo da maturidade fisiológica das sementes. O plantio foi realizado em 30 de setembro de 1996. Amostras de sementes dos híbridos simples CD 1723 e CD 5501, bem como do híbrido duplo OC 705, foram colhidas em intervalos de quatro dias, durante 59 dias, iniciando-se a colheita no vigésimo terceiro dia após o florescimento feminino. As características avaliadas nas sementes foram o acúmulo de matéria seca, o conteúdo de umidade, a germinação, o vigor (pelos testes de frio e de envelhecimento acelerado, a formação da camada preta e o desenvolvimento da linha de solidificação do endosperma. A colheita dos tr

  10. Genome-wide comparative in silico analysis of the RNA helicase gene family in Zea mays and Glycine max: a comparison with Arabidopsis and Oryza sativa.

    Science.gov (United States)

    Xu, Ruirui; Zhang, Shizhong; Huang, Jinguang; Zheng, Chengchao

    2013-01-01

    RNA helicases are enzymes that are thought to unwind double-stranded RNA molecules in an energy-dependent fashion through the hydrolysis of NTP. RNA helicases are associated with all processes involving RNA molecules, including nuclear transcription, editing, splicing, ribosome biogenesis, RNA export, and organelle gene expression. The involvement of RNA helicase in response to stress and in plant growth and development has been reported previously. While their importance in Arabidopsis and Oryza sativa has been partially studied, the function of RNA helicase proteins is poorly understood in Zea mays and Glycine max. In this study, we identified a total of RNA helicase genes in Arabidopsis and other crop species genome by genome-wide comparative in silico analysis. We classified the RNA helicase genes into three subfamilies according to the structural features of the motif II region, such as DEAD-box, DEAH-box and DExD/H-box, and different species showed different patterns of alternative splicing. Secondly, chromosome location analysis showed that the RNA helicase protein genes were distributed across all chromosomes with different densities in the four species. Thirdly, phylogenetic tree analyses identified the relevant homologs of DEAD-box, DEAH-box and DExD/H-box RNA helicase proteins in each of the four species. Fourthly, microarray expression data showed that many of these predicted RNA helicase genes were expressed in different developmental stages and different tissues under normal growth conditions. Finally, real-time quantitative PCR analysis showed that the expression levels of 10 genes in Arabidopsis and 13 genes in Zea mays were in close agreement with the microarray expression data. To our knowledge, this is the first report of a comparative genome-wide analysis of the RNA helicase gene family in Arabidopsis, Oryza sativa, Zea mays and Glycine max. This study provides valuable information for understanding the classification and putative functions of

  11. Combining Tpi and CO1 Genetic Markers to Discriminate Invasive Helicoverpa armigera From Local Helicoverpa zea (Lepidoptera: Noctuidae) Populations in the Southeastern United States.

    Science.gov (United States)

    Nagoshi, Rodney N; Gilligan, Todd M; Brambila, Julieta

    2016-10-01

    The recent establishment of the Old World pest Helicoverpa armigera (Hübner) into South America has had significant economic consequences and places the rest of the hemisphere at risk, emphasizing the need for improved methods of monitoring. A major complication is that a sibling species endemic to the New World, Helicoverpa zea (Boddie), is morphologically very similar, with the two species capable of producing fertile hybrids in the laboratory. The consequences of such hybridization in the field are uncertain, but could result in significant and unpredictable changes in the timing, range, and pesticide susceptibilities of Helicoverpa infestations. The objective here is to provide new genetic resources applicable to Helicoverpa populations in northern Florida and neighboring states (a region at risk for H. armigera) that can distinguish the two species and possible hybrids. The genetic variability in segments of the mitochondrial cytochrome oxidase 1 (CO1) and the Z-linked triosephosphate isomerase (Tpi) genes were determined for H. zea from the southeastern United States. These were compared to DNA sequences from H. armigera specimens from Morocco, Australia, and Europe. Phylogenetic network analysis showed a clear demarcation between the two species for all gene segments. These results extend earlier studies establishing CO1 as marker for discriminating the Helicoverpa species complex and introduce a new sex-linked genomic marker. The CO1 and Tpi markers in combination provide a more accurate and sensitive method than existing techniques for identifying hybridization between H. zea and H. armigera and could potentially be used to extrapolate the likely source of invasive H. armigera populations.

  12. Molecular analysis of CYP321A1, a novel cytochrome P450 involved in metabolism of plant allelochemicals (furanocoumarins) and insecticides (cypermethrin) in Helicoverpa zea.

    Science.gov (United States)

    Sasabe, Masataka; Wen, Zhimou; Berenbaum, May R; Schuler, Mary A

    2004-09-01

    Cytochrome P450 monooxygenases play a significant role in the detoxification of hostplant allelochemicals and synthetic insecticides in Lepidoptera. In the corn earworm Helicoverpa zea, a noctuid of considerable economic importance, metabolisms of xanthotoxin, a toxic furanocoumarin, and alpha-cypermethrin, an insecticide, are mediated by at least one P450 with a catalytic site capable of accepting both substrates. To further the characterization of P450s in this species, we have cloned three full-length cDNAs encoding two CYP4M subfamily members and a novel CYP321A subfamily member. RNA analyses have demonstrated that the CYP321A1 gene is highly induced (51-fold) in larval midguts in response to xanthotoxin but not cypermethrin. Both CYP4M genes are expressed at negligible levels that are not increased by xanthotoxin or cypermethrin. Baculovirus-mediated expression of the full-length CYP321A1 cDNA has demonstrated that the CYP321A1 protein metabolizes xanthotoxin and angelicin, like the CYP6B1 protein in the furanocoumarin specialist Papilio polyxenes, and alpha-cypermethrin, like the CYP6B8 protein previously characterized in H. zea. In contrast, the CYP4M7 protein does not metabolize xanthotoxin at any detectable level. We conclude that at least two xanthotoxin-inducible P450s from highly divergent subfamilies (CYP6B and CYP321A) contribute to the resistance of H. zea larvae to toxic furanocoumarins and insecticides. Genomic PCR analysis indicates that the CYP321A1 gene has evolved independently from the CYP6B genes known to be present in this insect.

  13. Effects on the accumulation of calcium, magnesium, iron, manganese, copper and zinc of adding the two inorganic forms of selenium to solution cultures of Zea mays.

    Science.gov (United States)

    Longchamp, M; Angeli, N; Castrec-Rouelle, M

    2016-01-01

    The addition of selenate or selenite to common fertilizers for crop production could be an effective way of producing selenium-rich food and feed. However, this would be feasible only if the increase in plant selenium (Se) content did not negatively influence the uptake of other essential elements. We therefore need to understand the interactions between Se and other major and trace elements during uptake by the plant. This study aimed to evaluate the influence of inorganic forms of Se on the accumulation of selected macronutrients (Ca and Mg) and micronutrients (Fe, Zn, Mn and Cu). Those essential elements are involved in the oxidative balance of cells. Zea mays seedlings were grown hydroponically in growth chambers in nutrient solutions to which we added 10, 50 or 1000 μg.L(-1) of selenate and/or selenite. Cation accumulation was significantly affected by the addition of 50 μg.L(-1) or 1000 μg.L(-1) Se, but not by the presence of 10 μg.L(-1) of Se in the nutrient solution. The highest concentration (1000 μg.L(-1)) of Se in the nutrient solution affected the accumulation of essential cations in Zea mays: selenate tended to increase the accumulation of Mg, Zn and Mn, whereas a selenate/selenite mixture tended to decrease the accumulation of Ca, Mg, Zn and Mn. Only Fe accumulation was unaffected by Se whatever its form or concentration. Selenium may also affect the distribution of cations on Zea mays. For example, levels of Mg and Zn translocation to the shoots were lower in the presence of selenite.

  14. Zea mays Taxilin protein negatively regulates opaque-2 transcriptional activity by causing a change in its sub-cellular distribution.

    Directory of Open Access Journals (Sweden)

    Nan Zhang

    Full Text Available Zea mays (maize Opaque-2 (ZmO2 protein is an important bZIP transcription factor that regulates the expression of major storage proteins (22-kD zeins and other important genes during maize seed development. ZmO2 is subject to functional regulation through protein-protein interactions. To unveil the potential regulatory network associated with ZmO2, a protein-protein interaction study was carried out using the truncated version of ZmO2 (O2-2 as bait in a yeast two-hybrid screen with a maize seed cDNA library. A protein with homology to Taxilin was found to have stable interaction with ZmO2 in yeast and was designated as ZmTaxilin. Sequence analysis indicated that ZmTaxilin has a long coiled-coil domain containing three conserved zipper motifs. Each of the three zipper motifs is individually able to interact with ZmO2 in yeast. A GST pull-down assay demonstrated the interaction between GST-fused ZmTaxilin and ZmO2 extracted from developing maize seeds. Using onion epidermal cells as in vivo assay system, we found that ZmTaxilin could change the sub-cellular distribution of ZmO2. We also demonstrated that this change significantly repressed the transcriptional activity of ZmO2 on the 22-kD zein promoter. Our study suggests that a Taxilin-mediated change in sub-cellular distribution of ZmO2 may have important functional consequences for ZmO2 activity.

  15. Characterization of photosynthetic performance during senescence in stay-green and quick-leaf-senescence Zea mays L. inbred lines.

    Science.gov (United States)

    Zhang, Zishan; Li, Geng; Gao, Huiyuan; Zhang, Litao; Yang, Cheng; Liu, Peng; Meng, Qingwei

    2012-01-01

    The net photosynthetic rate, chlorophyll content, chlorophyll fluorescence and 820 nm transmission were investigated to explore the behavior of the photosynthetic apparatus, including light absorption, energy transformation and the photoactivities of photosystem II (PSII) and photosystem I (PSI) during senescence in the stay-green inbred line of maize (Zea mays) Q319 and the quick-leaf-senescence inbred line of maize HZ4. The relationship between the photosynthetic performance and the decrease in chlorophyll content in the two inbred lines was also studied. Both the field and laboratory data indicated that the chlorophyll content, net photosynthetic rate, and the photoactivities of PSII and PSI decreased later and slower in Q319 than in HZ4, indicating that Q319 is a functional stay-green inbred line. In order to avoid the influence of different development stages and environmental factors on senescence, age-matched detached leaf segments from the two inbred lines were treated with ethephon under controlled conditions to induce senescence. The net photosynthetic rate, light absorption, energy transformation, the activities of PSII acceptor side and donor side and the PSI activities decreased much slower in Q319 than in HZ4 during the ethephon-induced senescence. These results suggest that the retention of light absorption, energy transformation and activity of electron transfer contribute to the extended duration of active photosynthesis in Q319. Although the chlorophyll content decreased faster in HZ4, with decrease of chlorophyll content induced by ethephon, photosynthetic performance of Q319 deteriorated much more severely than that of HZ4, indicating that, compared with Q319, HZ4 has an advantage at maintaining higher photosynthetic activity with decrease of chlorophyll although HZ4 is a quick-leaf-senescence inbred line. We conclude that attention should be paid to two favorable characteristics in breeding long duration of active photosynthesis hybrids: 1

  16. Chromosomal locations of the maize (Zea mays L. HtP and rt genes that confer resistance to Exserohilum turcicum

    Directory of Open Access Journals (Sweden)

    Juliana Bernardi Ogliari

    2007-01-01

    Full Text Available We used 125 microsatellite markers to genotype the maize (Zea mays L. near isogenic lines (NIL L30HtPHtPRtRt and L30htphtpRtRt and the L40htphtprtrt line which contrast regarding the presence of the recently described dominant HtP and the recessive rt genes that confer resistance to Exserohilum turcicum. Five microsatellite markers revealed polymorphisms between the NIL and were considered candidate linked markers for the HtP resistance gene. Linkage was confirmed by bulked segregant sample (BSS analysis of 32 susceptible and 34 resistant plants from a BC1F1 population derived from the cross (L30HtPHtPRtRt x L40htphtprtrt x L40htphtprtrt. The bnlg198 and dupssr25 markers, both located on maize chromosome 2L (bin 2.08, were polymorphic between bulks. Linkage distances were estimated based on co-segregation data of the 32 susceptible plants and indicated distances of 28.7 centimorgans (cM between HtP and bnlg198 and 23.5 cM between HtP and dupssr25. The same set of susceptible plants was also genotyped with markers polymorphic between L30HtPHtPRtRt and L40htphtprtrt in order to find markers linked to the rt gene. Marker bnlg197, from chromosome 3L (bin 3.06, was found linked to rt at a distance of 9.7 cM. This is the first report on the chromosomal locations of these newly described genes.

  17. Biology and natural enemies of Peregrinus maidis (Ashmead in corn (Zea mays L., in systems of polycrops

    Directory of Open Access Journals (Sweden)

    Marcos Tulio García González

    2015-02-01

    Full Text Available This research was done in Fomento municipality, Sancti Spíritus, in Cuba, from 2011 through 2013 in two ecosystems and in two sowing times (rainy and dry seasons. The objectives were to describe the life cycle of Peregrinus maidis (Ashmead and the damage caused to corn (Zea mays L., to identify the main pest bio-regulators naturally occurring in two agro-ecosystems, and to determine the predator-prey relationship. The experiment was arranged in a randomized block design. The data were collected through observation at weekly intervals. In order to estimate the number of pest insects and bio-regulators occurring on the plants, 25 plants per parcel were selected for a total of 100 plants per treatment (maize/squash, maize/beans, maize/ Sesame, maize/sunflower, and maize monoculture. Once the research was accomplished, it was concluded that P maidis had been present since the first week, and reached its population peak in week six. The lower indexes of affectation occurred in the pre-mountain agro-ecosystems, and with more frequency in the maize/sesame and maize/squash polyculture, which depended on the time of the year and the season. Fifteen species of P. maidis control insects of were identified, and Scymnus sp was found in all treatments. The life cycle of P maidis averaged 5.4 days more in the dry season than in rain season. The predator-prey relationship showed relatively superior indexes in the polyculture systems than in monocrops systems.

  18. Identification and suppression of the p-coumaroyl CoA:hydroxycinnamyl alcohol transferase in Zea mays L.

    Science.gov (United States)

    Marita, Jane M; Hatfield, Ronald D; Rancour, David M; Frost, Kenneth E

    2014-06-01

    Grasses, such as Zea mays L. (maize), contain relatively high levels of p-coumarates (pCA) within their cell walls. Incorporation of pCA into cell walls is believed to be due to a hydroxycinnamyl transferase that couples pCA to monolignols. To understand the role of pCA in maize development, the p-coumaroyl CoA:hydroxycinnamyl alcohol transferase (pCAT) was isolated and purified from maize stems. Purified pCAT was subjected to partial trypsin digestion, and peptides were sequenced by tandem mass spectrometry. TBLASTN analysis of the acquired peptide sequences identified a single full-length maize cDNA clone encoding all the peptide sequences obtained from the purified enzyme. The cDNA clone was obtained and used to generate an RNAi construct for suppressing pCAT expression in maize. Here we describe the effects of suppression of pCAT in maize. Primary screening of transgenic maize seedling leaves using a new rapid analytical platform was used to identify plants with decreased amounts of pCA. Using this screening method, mature leaves from fully developed plants were analyzed, confirming reduced pCA levels throughout plant development. Complete analysis of isolated cell walls from mature transgenic stems and leaves revealed that lignin levels did not change, but pCA levels decreased and the lignin composition was altered. Transgenic plants with the lowest levels of pCA had decreased levels of syringyl units in the lignin. Thus, altering the levels of pCAT expression in maize leads to altered lignin composition, but does not appear to alter the total amount of lignin present in the cell walls.

  19. Impacts of industrial waste resources on maize (Zea mays L.) growth, yield, nutrients uptake and soil properties.

    Science.gov (United States)

    Singh, Satnam; Young, Li-Sen; Shen, Fo-Ting; Young, Chiu-Chung

    2014-10-01

    Discharging untreated highly acidic (pH10.0) paper-mill wastewater (PW) causes environmental pollution. When acidity of MW neutralized (pH 6.5±0.1) with PW and lime (treatments represented as MW+PW and MW+Lime), then MW may be utilized as a potential source of nutrients and organic carbon for sustainable food production. Objectives of this study were to compare the effects of PW and lime neutralized MW and chemical fertilizers on maize (Zea mays L. cv. Snow Jean) plant growth, yield, nutrients uptake, soil organic matter and humic substances. The field experiment was carried out on maize using MW at 6000 L ha(-1). Impacts of the MW application on maize crop and soil properties were evaluated at different stages. At harvest, plant height, and plant N and K uptake were higher in MW treatment. Leaf area index at 60 days after sowing, plant dry matter accumulation at harvest, and kernels ear(-1) and 100-kernel weight were higher in MW+Lime treatment. Kernel N, P, K, Mn, Fe and Zn, and plant Zn uptake were highest in MW+Lime. Plant Fe uptake, and soil organic matter and humic substances were highest in MW+PW. The MW+PW and MW+Lime treatments exhibited comparable results with chemically fertilized treatment. The MW acidity neutralized with lime showed positive impacts on growth, yield and nutrients uptake; nevertheless, when MW pH neutralized with PW has an additional benefit on increase in soil organic matter and humic substances.

  20. Phytoremediation for co-contaminated soils of chromium and benzo[a]pyrene using Zea mays L.

    Science.gov (United States)

    Chigbo, Chibuike; Batty, Lesley

    2014-02-01

    A greenhouse experiment was carried out to investigate the single effect of benzo[a]pyrene (B[a]P) or chromium (Cr) and the joint effect of Cr-B[a]P on the growth of Zea mays, its uptake and accumulation of Cr, and the dissipation of B[a]P over 60 days. Results showed that single or joint contamination of Cr and B[a]P did not affect the plant growth relative to control treatments. However, the occurrence of B[a]P had an enhancing effect on the accumulation and translocation of Cr. The accumulation of Cr in shoot of plant significantly increased by ≥ 79 % in 50 mg kg(-1) Cr-B[a]P (1, 5, and 10 mg kg(-1)) treatments and by ≥ 86 % in 100 mg kg(-1) Cr-B[a]P (1, 5, and 10 mg kg(-1)) treatments relative to control treatments. The presence of plants did not enhance the dissipation of B[a]P in lower (1and 5 mg kg(-1)) B[a]P contaminated soils; however, over 60 days of planting Z. mays seemed to enhance the dissipation of B[a]P by over 60 % in 10 mg kg(-1) single contaminated soil and by 28 to 41 % in 10 mg kg(-1)B[a]P co-contaminated soil. This suggests that Z. mays might be a useful plant for the remediation of Cr-B[a]P co-contaminated soil.

  1. Effects of citrate-coated silver nanoparticles on interactions between soil bacteria and the major crop plant Zea mays

    Science.gov (United States)

    Doody, Michael; Bais, Harsh; Jin, Yan

    2014-05-01

    The increasing use of silver nanoparticles (AgNPs) in commercial antimicrobial products presents an opportunity for increased environmental exposures. While the behavior of AgNPs in surface waters is becoming increasingly understood, little research has been conducted on the effects of these, or any nanoparticles, on soil-dwelling bacteria and major crop plants. Because of the importance of soil bacteria to the overall health of natural and agricultural soils, it is necessary to better understand how AgNPs interact with common bacterial species such as Bacillus subtilis and Escherichia coli. It is further necessary to quantify the effect of AgNPs on major crop plants, including Zea mays, a staple crop for much of the world. Finally, research is needed on how complex plant-microbe interactions that originate in the rhizosphere may be disrupted by AgNPs. Our preliminary data show highly statistically significant growth inhibition near 30% for both species of bacteria exposed to 1.0 mg L-1 citrate-coated AgNPs (c-AgNPs). Growth curves compiled from absorbance data show a similar dose-response for both species. Treatment with aqueous Ag as AgNO3 slightly inhibits E. coli (90 ± 5 %), but enhances growth of B. subtilis to 127 ± 23% of control. These results indicate that toxicity may be related to specific nano-scale properties of the c-AgNPs. On-going experiments measure potential growth inhibition, root development and morphology of Z. mays exposed to c-AgNPs, and resulting changes in plant-microbe interactions.

  2. Genome-wide identification, splicing, and expression analysis of the myosin gene family in maize (Zea mays).

    Science.gov (United States)

    Wang, Guifeng; Zhong, Mingyu; Wang, Jiajia; Zhang, Jushan; Tang, Yuanping; Wang, Gang; Song, Rentao

    2014-03-01

    The actin-based myosin system is essential for the organization and dynamics of the endomembrane system and transport network in plant cells. Plants harbour two unique myosin groups, class VIII and class XI, and the latter is structurally and functionally analogous to the animal and fungal class V myosin. Little is known about myosins in grass, even though grass includes several agronomically important cereal crops. Here, we identified 14 myosin genes from the genome of maize (Zea mays). The relatively larger sizes of maize myosin genes are due to their much longer introns, which are abundant in transposable elements. Phylogenetic analysis indicated that maize myosin genes could be classified into class VIII and class XI, with three and 11 members, respectively. Apart from subgroup XI-F, the remaining subgroups were duplicated at least in one analysed lineage, and the duplication events occurred more extensively in Arabidopsis than in maize. Only two pairs of maize myosins were generated from segmental duplication. Expression analysis revealed that most maize myosin genes were expressed universally, whereas a few members (XI-1, -6, and -11) showed an anther-specific pattern, and many underwent extensive alternative splicing. We also found a short transcript at the O1 locus, which conceptually encoded a headless myosin that most likely functions at the transcriptional level rather than via a dominant-negative mechanism at the translational level. Together, these data provide significant insights into the evolutionary and functional characterization of maize myosin genes that could transfer to the identification and application of homologous myosins of other grasses.

  3. Cadmium toxicity in Maize (Zea mays L.): consequences on antioxidative systems, reactive oxygen species and cadmium accumulation.

    Science.gov (United States)

    Anjum, Shakeel Ahmad; Tanveer, Mohsin; Hussain, Saddam; Bao, Mingchen; Wang, Longchang; Khan, Imran; Ullah, Ehsan; Tung, Shahbaz Atta; Samad, Rana Abdul; Shahzad, Babar

    2015-11-01

    Increased cadmium (Cd) accumulation in soils has led to tremendous environmental problems, with pronounced effects on agricultural productivity. Present study investigated the effects of Cd stress imposed at various concentrations (0, 75, 150, 225, 300, 375 μM) on antioxidant activities, reactive oxygen species (ROS), Cd accumulation, and productivity of two maize (Zea mays L.) cultivars viz., Run Nong 35 and Wan Dan 13. Considerable variations in Cd accumulation and in behavior of antioxidants and ROS were observed under Cd stress in both maize cultivars, and such variations governed by Cd were concentration dependent. Exposure of plant to Cd stress considerably increased Cd concentration in all plant parts particularly in roots. Wan Dan 13 accumulated relatively higher Cd in root, stem, and leaves than Run Nong 35; however, in seeds, Run Nong 35 recorded higher Cd accumulation. All the Cd toxicity levels starting from 75 μM enhanced H2O2 and MDA concentrations and triggered electrolyte leakage in leaves of both cultivars, and such an increment was more in Run Nong 35. The ROS were scavenged by the enhanced activities of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, and glutathione peroxidase in response to Cd stress, and these antioxidant activities were higher in Wan Dan 13 compared with Run Nong 35 at all Cd toxicity levels. The grain yield of maize was considerably reduced particularly for Run Nong 35 under different Cd toxicity levels as compared with control. The Wan Dan 13 was better able to alleviate Cd-induced oxidative damage which was attributed to more Cd accumulation in roots and higher antioxidant activities in this cultivar, suggesting that manipulation of these antioxidants and enhancing Cd accumulation in roots may lead to improvement in Cd stress tolerance.

  4. Changes in nucleosome position at transcriptional start sites of specific genes in Zea mays mediator of paramutation1 mutants.

    Science.gov (United States)

    Labonne, Jonathan D J; Dorweiler, Jane E; McGinnis, Karen M

    2013-04-01

    Nucleosomes facilitate compaction of DNA within the confines of the eukaryotic nucleus. This packaging of DNA and histone proteins must accommodate cellular processes, such as transcription and DNA replication. The repositioning of nucleosomes to facilitate cellular processes is likely regulated by several factors. In Zea mays, Mediator of paramutation1 (MOP1) has been demonstrated to be an epigenetic regulator of gene expression. Based on sequence orthology and mutant phenotypes, MOP1 is likely to function in an RNA-dependent pathway to mediate changes to chromatin. High-resolution microarrays were used to assay the distribution of nucleosomes across the transcription start sites (TSSs) of ~400 maize genes in wild type and mutant mop1-1 tissues. Analysis of nucleosome distribution in leaf, immature tassel and ear shoot tissues resulted in the identification of three genes showing consistent differences in nucleosome positioning and occupancy between wild type and mutant mop1-1. These specific changes in nucleosome distribution were located upstream as well as downstream of the TSS. No direct relationship between the specific changes in nucleosome distribution and transcription were observed through quantitative expression analysis in these tissues. In silico prediction suggests that nucleosome positioning is not dictated by intrinsic DNA sequence signals in the TSSs of two of the identified genes, suggesting a role for chromatin remodeling proteins in MOP1-mediated pathways. These results also indicate that MOP1 contributions to nucleosome position may be either separate from changes in gene expression, or cooperative with development and other levels of regulation in coordinating gene expression.

  5. A novel beta-glucosidase from the cell wall of maize (Zea mays L.): rapid purification and partial characterization

    Science.gov (United States)

    Nematollahi, W. P.; Roux, S. J.

    1999-01-01

    Plants have a variety of glycosidic conjugates of hormones, defense compounds, and other molecules that are hydrolyzed by beta-glucosidases (beta-D-glucoside glucohydrolases, E.C. 3.2.1.21). Workers have reported several beta-glucosidases from maize (Zea mays L.; Poaceae), but have localized them mostly by indirect means. We have purified and partly characterized a 58-Ku beta-glucosidase from maize, which we conclude from a partial sequence analysis, from kinetic data, and from its localization is not identical to any of those already reported. A monoclonal antibody, mWP 19, binds this enzyme, and localizes it in the cell walls of maize coleoptiles. An earlier report showed that mWP19 inhibits peroxidase activity in crude cell wall extracts and can immunoprecipitate peroxidase activity from these extracts, yet purified preparations of the 58 Ku protein had little or no peroxidase activity. The level of sequence similarity between beta-glucosidases and peroxidases makes it unlikely that these enzymes share epitopes in common. Contrary to a previous conclusion, these results suggest that the enzyme recognized by mWP19 is not a peroxidase, but there is a wall peroxidase closely associated with the 58 Ku beta-glucosidase in crude preparations. Other workers also have co-purified distinct proteins with beta-glucosidases. We found no significant charge in the level of immunodetectable beta-glucosidase in mesocotyls or coleoptiles that precedes the red light-induced changes in the growth rate of these tissues.

  6. Effects of ethylene on the kinetics of curvature and auxin redistribution in gravistimulated roots of Zea mays

    Science.gov (United States)

    Lee, J. S.; Evans, M. L.

    1990-01-01

    We tested the involvement of ethylene in maize (Zea mays L.) root gravitropism by measuring the kinetics of curvature and lateral auxin movement in roots treated with ethylene, inhibitors of ethylene synthesis, or inhibitors of ethylene action. In the presence of ethylene the latent period of gravitropic curvature appeared to be increased somewhat. However, ethylene-treated roots continued to curve after control roots had reached their final angle of curvature. Consequently, maximum curvature in the presence of ethylene was much greater in ethylene-treated roots than in controls. Inhibitors of ethylene biosynthesis or action had effects on the kinetics of curvature opposite to that of ethylene, i.e. the latent period appeared to be shortened somewhat while total curvature was reduced relative to that of controls. Label from applied 3H-indole-3-acetic acid was preferentially transported toward the lower side of stimulated roots. In parallel with effects on curvature, ethylene treatment delayed the development of gravity-induced asymmetric auxin movement across the root but extended its duration once initiated. The auxin transport inhibitor, 1-N-naphthylphthalamic acid reduced both gravitropic curvature and the effect of ethylene on curvature. Since neither ethylene nor inhibitors of ethylene biosynthesis or action prevented curvature, we conclude that ethylene does not mediate the primary differential growth response causing curvature. Because ethylene affects curvature and auxin transport in parallel, we suggest that ethylene modifies curvature by affecting gravity-induced lateral transport of auxin, perhaps by interfering with adaptation of the auxin transport system to the gravistimulus.

  7. Phytotoxic cyanamide affects maize (Zea mays) root growth and root tip function: from structure to gene expression.

    Science.gov (United States)

    Soltys, Dorota; Rudzińska-Langwald, Anna; Kurek, Wojciech; Szajko, Katarzyna; Sliwinska, Elwira; Bogatek, Renata; Gniazdowska, Agnieszka

    2014-05-01

    Cyanamide (CA) is a phytotoxic compound produced by four Fabaceae species: hairy vetch, bird vetch, purple vetch and black locust. Its toxicity is due to complex activity that involves the modification of both cellular structures and physiological processes. To date, CA has been investigated mainly in dicot plants. The goal of this study was to investigate the effects of CA in the restriction of the root growth of maize (Zea mays), representing the monocot species. CA (3mM) reduced the number of border cells in the root tips of maize seedlings and degraded their protoplasts. However, CA did not induce any significant changes in the organelle structure of other root cells, apart from increased vacuolization. CA toxicity was also demonstrated by its effect on cell cycle activity, endoreduplication intensity, and modifications of cyclins CycA2, CycD2, and histone HisH3 gene expression. In contrast, the arrangement of microtubules was not altered by CA. Treatment of maize seedlings with CA did not completely arrest mitotic activity, although the frequency of dividing cells was reduced. Furthermore, prolonged CA treatment increased the proportion of endopolyploid cells in the root tip. Cytological malformations were accompanied by an induction of oxidative stress in root cells, which manifested as enhanced accumulation of H2O2. Exposure of maize seedlings to CA resulted in an increased concentration of auxin and stimulated ethylene emission. Taken together, these findings suggested that the inhibition of root growth by CA may be a consequence of stress-induced morphogenic responses.

  8. Development of neuropeptide analogs capable of traversing the integument: A case study using diapause hormone analogs in Helicoverpa zea.

    Science.gov (United States)

    Zhang, Qirui; Nachman, Ronald J; Kaczmarek, Krzysztof; Kierus, Krzysztof; Zabrocki, Janusz; Denlinger, David L

    2015-12-01

    Diapause hormone and its analogs terminate pupal diapause in Helicoverpa zea when injected, but if such agents are to be used as effective diapause disruptors it will be essential to develop simple techniques for administering active compounds that can exert their effect by penetrating the insect epidermis. In the current study, we used two molecules previously shown to have high diapause-terminating activity as lead molecules to rationally design and synthesize new amphiphilic compounds with modified hydrophobic components. An assay for diapause termination identified 13 active compounds with EC50's ranging from 0.9 to 46.0 pmol per pupa. Three compounds, Decyl-1963, Dodecyl-1967, and Heptyl-1965, selected from the 13 compounds most active in breaking diapause following injection, also successfully prevented newly-formed pupae from entering diapause when applied topically. These compounds feature straight-chain, aliphatic hydrocarbons from 7 to 12 carbons in length; DH analogs with either a short-chain length of 4 or an aromatic phenethyl group failed to act topically. Compared to a high diapause incidence of 80-90% in controls, diapause incidence in pupae receiving a 10 nmole topical application of Decyl-1963, Dodecyl-1967, or Heptyl-1965 dropped to 30-45%. Decyl-1963 and Dodecyl-1967 also remained effective when topically applied at the 1 nmole level. These results suggest the feasibility of developing DH agonists that can be applied topically and suggest the identity of new lead molecules for development of additional topically-active DH analogs. The ability to penetrate the insect epidermis and/or midgut lining is critical if such agents are to be considered for future use as pest management tools.

  9. Species differences in ligand specificity of auxin-controlled elongation and auxin transport: comparing Zea and Vigna

    Science.gov (United States)

    Zhao, Hu; Hertel, Rainer; Ishikawa, Hideo; Evans, Michael L.

    2002-01-01

    The plant hormone auxin affects cell elongation in both roots and shoots. In roots, the predominant action of auxin is to inhibit cell elongation while in shoots auxin, at normal physiological levels, stimulates elongation. The question of whether the primary receptor for auxin is the same in roots and shoots has not been resolved. In addition to its action on cell elongation in roots and shoots, auxin is transported in a polar fashion in both organs. Although auxin transport is well characterized in both roots and shoots, there is relatively little information on the connection, if any, between auxin transport and its action on elongation. In particular, it is not clear whether the protein mediating polar auxin movement is separate from the protein mediating auxin action on cell elongation or whether these two processes might be mediated by one and the same receptor. We examined the identity of the auxin growth receptor in roots and shoots by comparing the response of roots and shoots of the grass Zea mays L. and the legume Vigna mungo L. to indole-3-acetic acid, 2-naphthoxyacetic acid, 4,6-dichloroindoleacetic acid, and 4,7-dichloroindoleacetic acid. We also studied whether or not a single protein might mediate both auxin transport and auxin action by comparing the polar transport of indole-3-acetic acid and 2-naphthoxyacetic acid through segments from Vigna hypocotyls and maize coleoptiles. For all of the assays performed (root elongation, shoot elongation, and polar transport) the action and transport of the auxin derivatives was much greater in the dicots than in the grass species. The preservation of ligand specificity between roots and shoots and the parallels in ligand specificity between auxin transport and auxin action on growth are consistent with the hypothesis that the auxin receptor is the same in roots and shoots and that this protein may mediate auxin efflux as well as auxin action in both organ types.

  10. An 11-bp insertion in Zea mays fatb reduces the palmitic acid content of fatty acids in maize grain.

    Directory of Open Access Journals (Sweden)

    Lin Li

    Full Text Available The ratio of saturated to unsaturated fatty acids in maize kernels strongly impacts human and livestock health, but is a complex trait that is difficult to select based on phenotype. Map-based cloning of quantitative trait loci (QTL is a powerful but time-consuming method for the dissection of complex traits. Here, we combine linkage and association analyses to fine map QTL-Pal9, a QTL influencing levels of palmitic acid, an important class of saturated fatty acid. QTL-Pal9 was mapped to a 90-kb region, in which we identified a candidate gene, Zea mays fatb (Zmfatb, which encodes acyl-ACP thioesterase. An 11-bp insertion in the last exon of Zmfatb decreases palmitic acid content and concentration, leading to an optimization of the ratio of saturated to unsaturated fatty acids while having no effect on total oil content. We used three-dimensional structure analysis to explain the functional mechanism of the ZmFATB protein and confirmed the proposed model in vitro and in vivo. We measured the genetic effect of the functional site in 15 different genetic backgrounds and found a maximum change of 4.57 mg/g palmitic acid content, which accounts for ∼20-60% of the variation in the ratio of saturated to unsaturated fatty acids. A PCR-based marker for QTL-Pal9 was developed for marker-assisted selection of nutritionally healthier maize lines. The method presented here provides a new, efficient way to clone QTL, and the cloned palmitic acid QTL sheds lights on the genetic mechanism of oil biosynthesis and targeted maize molecular breeding.

  11. Helicoverpa zea (Lepidoptera: Noctuidae) and Spodoptera frugiperda (Lepidoptera: Noctuidae) Responses to Sorghum bicolor (Poales: Poaceae) Tissues From Lowered Lignin Lines.

    Science.gov (United States)

    Dowd, Patrick F; Sattler, Scott E

    2015-01-01

    The presence of lignin within biomass impedes the production of liquid fuels. Plants with altered lignin content and composition are more amenable to lignocellulosic conversion to ethanol and other biofuels but may be more susceptible to insect damage where lignin is an important resistance factor. However, reduced lignin lines of switchgrasses still retained insect resistance in prior studies. Therefore, we hypothesized that sorghum lines with lowered lignin content will also retain insect resistance. Sorghum excised leaves and stalk pith Sorghum bicolor (L.) Moench (Poales: Poaceae) from near isogenic brown midrib (bmr) 6 and 12 mutants lines, which have lowered lignin content and increased lignocellulosic ethanol conversion efficiency, were examined for insect resistance relative to wild-type (normal BTx623). Greenhouse and growth chamber grown plant tissues were fed to first-instar larvae of corn earworms, Helicoverpa zea (Boddie) and fall armyworms Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), two sorghum major pests. Younger bmr leaves had significantly greater feeding damage in some assays than wild-type leaves, but older bmr6 leaves generally had significantly less damage than wild-type leaves. Caterpillars feeding on the bmr6 leaves often weighed significantly less than those feeding on wild-type leaves, especially in the S. frugiperda assays. Larvae fed the pith from bmr stalks had significantly higher mortality compared with those larvae fed on wild-type pith, which suggested that bmr pith was more toxic. Thus, reducing lignin content or changing subunit composition of bioenergy grasses does not necessarily increase their susceptibility to insects and may result in increased resistance, which would contribute to sustainable production.

  12. Kinetics of NH(4) Assimilation in Zea mays: Preliminary Studies with a Glutamate Dehydrogenase (GDH1) Null Mutant.

    Science.gov (United States)

    Magalhães, J R; Ju, G C; Rich, P J; Rhodes, D

    1990-10-01

    In higher plants it is now generally considered that glutamate dehydrogenase (GDH) plays only a small or negligible role in ammonia assimilation. To test this specific point, comparative studies of (15)NH(4) (+) assimilation were undertaken with a GDH1-null mutant of Zea mays and a related (but not strictly isogenic) GDH1-positive wild type from which this mutant was derived. The kinetics of (15)NH(4) (+) assimilation into free amino acids and total reduced nitrogen were monitored in both roots and shoots of 2-week-old seedlings supplied with 5 millimolar 99% ((15)NH(4))(2)SO(4) via the aerated root medium in hydroponic culture over a 24-h period. The GDH1-null mutant, with a 10- to 15-fold lower total root GDH activity in comparison to the wild type, was found to exhibit a 40 to 50% lower rate of (15)NH(4) (+) assimilation into total reduced nitrogen. Observed rates of root ammonium assimilation were 5.9 and 3.1 micromoles per hour per gram fresh weight for the wild type and mutant, respectively. The lower rate of (15)NH(4) (+) assimilation in the mutant was associated with lower rates of labeling of several free amino acids (including glutamate, glutamine-amino N, aspartate, asparagine-amino N, and alanine) in both roots and shoots of the mutant in comparison to the wild type. Qualitatively, these labeling kinetics appear consistent with a reduced flux of (15)N via glutamate in the GDH1-null mutant. However, the responses of the two genotypes to the potent inhibitor of glutamine synthetase, methionine sulfoximine, and differences in morphology of the two genotypes (particularly a lower shoot:root ratio in the GDH1-null mutant) urge caution in concluding that GDH1 is solely responsible for these differences in ammonia assimilation rate.

  13. Effect of phosphate solubilizing microorganisms on quantitative and qualitative characteristics of maize (Zea mays L.) under water deficit stress.

    Science.gov (United States)

    Ehteshami, S M R; Aghaalikhani, M; Khavazi, K; Chaichi, M R

    2007-10-15

    The effect of seed inoculation by phosphate solubilizing microorganisms on growth, yield and nutrient uptake of maize (Zea mays L. SC. 704) was studied in a field experiment. Positive effect on plant growth, nutrient uptake, grain yield and yield components in maize plants was recorded in the treatment receiving mixed inoculum of Glomus intraradices (AM) and Pseudomonas fluorescens (Pf). Co-inoculation treatment significantly increased grain yield, yield components, harvest index, grain N and P, soil available P, root colonization percentage and crop WUE under water deficit stress. In some of investigated characteristics under well-watered conditions, chemical fertilizer treatment was higher than double inoculated treatments, but this difference was not significant. Seed inoculation only with AM positively affected the measured parameters as amount as co-inoculated treatments. According to the results showed in contrast to the inoculated treatments with AM+Pf and AM, the application of alone Pf caused a comparatively poor response. Therefore, this microorganism needs to a complement for its activity in soil. All of measured parameters in inoculated treatments were higher than uninoculated treatments under water deficit stress conditions. Furthermore, the investigated characteristics of co-inoculated plants under severe water deficit stress conditions were significantly lower than co-inoculated plants under well-watered and moderate-stressed conditions. Therefore it could be stated, these microorganisms need more time to fix and establishing themselves in soil. The present finding showed that phosphate-solubilizing microorganisms can interact positively in promoting plant growth as well as P uptake of maize plants, leading to plant tolerance improving under water deficit stress conditions.

  14. An 11-bp insertion in Zea mays fatb reduces the palmitic acid content of fatty acids in maize grain.

    Science.gov (United States)

    Li, Lin; Li, Hui; Li, Qing; Yang, Xiaohong; Zheng, Debo; Warburton, Marilyn; Chai, Yuchao; Zhang, Pan; Guo, Yuqiu; Yan, Jianbing; Li, Jiansheng

    2011-01-01

    The ratio of saturated to unsaturated fatty acids in maize kernels strongly impacts human and livestock health, but is a complex trait that is difficult to select based on phenotype. Map-based cloning of quantitative trait loci (QTL) is a powerful but time-consuming method for the dissection of complex traits. Here, we combine linkage and association analyses to fine map QTL-Pal9, a QTL influencing levels of palmitic acid, an important class of saturated fatty acid. QTL-Pal9 was mapped to a 90-kb region, in which we identified a candidate gene, Zea mays fatb (Zmfatb), which encodes acyl-ACP thioesterase. An 11-bp insertion in the last exon of Zmfatb decreases palmitic acid content and concentration, leading to an optimization of the ratio of saturated to unsaturated fatty acids while having no effect on total oil content. We used three-dimensional structure analysis to explain the functional mechanism of the ZmFATB protein and confirmed the proposed model in vitro and in vivo. We measured the genetic effect of the functional site in 15 different genetic backgrounds and found a maximum change of 4.57 mg/g palmitic acid content, which accounts for ∼20-60% of the variation in the ratio of saturated to unsaturated fatty acids. A PCR-based marker for QTL-Pal9 was developed for marker-assisted selection of nutritionally healthier maize lines. The method presented here provides a new, efficient way to clone QTL, and the cloned palmitic acid QTL sheds lights on the genetic mechanism of oil biosynthesis and targeted maize molecular breeding.

  15. Pre-treatment of seeds with static magnetic field ameliorates soil water stress in seedlings of maize (Zea mays L.).

    Science.gov (United States)

    Anand, Anjali; Nagarajan, Shantha; Verma, A P S; Joshi, D K; Pathak, P C; Bhardwaj, Jyotsna

    2012-02-01

    The effect of magnetic field (MF) treatments of maize (Zea mays L.) var. Ganga Safed 2 seeds on the growth, leaf water status, photosynthesis and antioxidant enzyme system under soil water stress was investigated under greenhouse conditions. The seeds were exposed to static MFs of 100 and 200 mT for 2 and 1 h, respectively. The treated seeds were sown in sand beds for seven days and transplanted in pots that were maintained at -0.03, -0.2 and -0.4 MPa soil water potentials under greenhouse conditions. MF exposure of seeds significantly enhanced all growth parameters, compared to the control seedlings. The significant increase in root parameters in seedlings from magnetically-exposed seeds resulted in maintenance of better leaf water status in terms of increase in leaf water potential, turgor potential and relative water content. Photosynthesis, stomatal conductance and chlorophyll content increased in plants from treated seeds, compared to control under irrigated and mild stress condition. Leaves from plants of magnetically-treated seeds showed decreased levels of hydrogen peroxide and antioxidant defense system enzymes (peroxidases, catalase and superoxide dismutase) under moisture stress conditions, when compared with untreated controls. Mild stress of -0.2 MPa induced a stimulating effect on functional root parameters, especially in 200 mT treated seedlings which can be exploited profitably for rain fed conditions. Our results suggested that MF treatment (100 mT for 2 h and 200 for 1 h) of maize seeds enhanced the seedling growth, leaf water status, photosynthesis rate and lowered the antioxidant defense system of seedlings under soil water stress. Thus, pre sowing static magnetic field treatment of seeds can be effectively used for improving growth under water stress.

  16. Characterization of water distribution and activities of enzymes during germination in magnetically-exposed maize (Zea mays L) seeds.

    Science.gov (United States)

    Vashisth, Ananta; Nagarajan, Shantha

    2010-10-01

    Magnetic seed treatment is one of the physical pre-sowing seed treatments to enhance the performance of crop plants. In our earlier experiment, we found significant increase in germination and vigour characteristics of maize (Zea mays L.) seeds subjected to magnetic fields. Among various combinations of magnetic field (MF) strength and duration, best results were obtained with MF of 100 mT for 2 h and 200 mT for 1 h exposure. The quicker germination in magnetically-exposed seeds might be due to greater activities of germination related enzymes, early hydration of membranes as well as greater molecular mobility of bulk and hydration water fractions. Thus, in the present study, changes in water uptake during imbibition and its distribution and activities of germinating enzymes during germination were investigated in maize seeds exposed to static magnetic fields of 100 and 200 mT for 2 and 1 h respectively by nuclear magnetic resonance (NMR) spectroscopy. The magnetically-exposed seed showed higher water uptake in phase II and III than unexposed seed. The longitudinal relaxation time T1 of seed water showed significantly higher values and hence greater molecular mobility of cellular water in magnetically-exposed seeds as compared to unexposed. Component analysis of T2 relaxation times revealed the early appearance of hydration water with least mobility and higher values of relaxation times of cytoplasmic bulk water and hydration water in magnetically-exposed over unexposed seeds. Activities of alpha-amylase, dehydorgenase and protease during germination were higher in magnetically-exposed seeds as compared to unexposed. The quicker germination in magnetically-exposed seeds might be due to greater activities of germination related enzymes, early hydration of membranes as well as greater molecular mobility of bulk and hydration water fractions.

  17. Uptake and effects of a mixture of widely used therapeutic drugs in Eruca sativa L. and Zea mays L. plants.

    Science.gov (United States)

    Marsoni, Milena; De Mattia, Fabrizio; Labra, Massimo; Bruno, Antonia; Bruno, Antonella; Bracale, Marcella; Vannini, Candida

    2014-10-01

    Pharmaceutically active compounds (PACs) are continuously dispersed into the environment due to human and veterinary use, giving rise to their potential accumulation in edible plants. In this study, Eruca sativa L. and Zea mays L. were selected to determine the potential uptake and accumulation of eight different PACs (Salbutamol, Atenolol, Lincomycin, Cyclophosphamide, Carbamazepine, Bezafibrate, Ofloxacin and Ranitidine) designed for human use. To mimic environmental conditions, the plants were grown in pots and irrigated with water spiked with a mixture of PACs at concentrations found in Italian wastewaters and rivers. Moreover, 10× and 100× concentrations of these pharmaceuticals were also tested. The presence of the pharmaceuticals was tested in the edible parts of the plants, namely leaves for E. sativa and grains for Z. mays. Quantification was performed by liquid chromatography mass spectroscopy (LC/MS/MS). In the grains of 100× treated Z. mays, only atenolol, lincomycin and carbamazepine were above the limit of detection (LOD). At the same concentration in E. sativa plants the uptake of all PACs was >LOD. Lincomycin and oflaxacin were above the limit of quantitation in all conditions tested in E. sativa. The results suggest that uptake of some pharmaceuticals from the soil may indeed be a potential transport route to plants and that these environmental pollutants can reach different edible parts of the selected crops. Measurements of the concentrations of these pharmaceuticals in plant materials were used to model potential adult human exposure to these compounds. The results indicate that under the current experimental conditions, crops exposed to the selected pharmaceutical mixture would not have any negative effects on human health. Moreover, no significant differences in the growth of E. sativa or Z. mays plants irrigated with PAC-spiked vs. non-spiked water were observed.

  18. Abscisic acid refines the synthesis of chloroplast proteins in maize (Zea mays in response to drought and light.

    Directory of Open Access Journals (Sweden)

    Xiuli Hu

    Full Text Available To better understand abscisic acid (ABA regulation of the synthesis of chloroplast proteins in maize (Zea mays L. in response to drought and light, we compared leaf proteome differences between maize ABA-deficient mutant vp5 and corresponding wild-type Vp5 green and etiolated seedlings exposed to drought stress. Proteins extracted from the leaves of Vp5 and vp5 seedlings were used for two-dimensional electrophoresis (2-DE and subsequent matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF mass spectrometry (MS. After Coomassie brilliant blue staining, approximately 450 protein spots were reproducibly detected on 2-DE gels. A total of 36 differentially expressed protein spots in response to drought and light were identified using MALDI-TOF MS and their subcellular localization was determined based on the annotation of reviewed accession in UniProt Knowledgebase and the software prediction. As a result, corresponding 13 proteins of the 24 differentially expressed protein spots were definitely localized in chloroplasts and their expression was in an ABA-dependent way, including 6 up-regulated by both drought and light, 5 up-regulated by drought but down-regulated by light, 5 up-regulated by light but down-regulated by drought; 5 proteins down-regulated by drought were mainly those involved in photosynthesis and ATP synthesis. Thus, the results in the present study supported the vital role of ABA in regulating the synthesis of drought- and/or light-induced proteins in maize chloroplasts and would facilitate the functional characterization of ABA-induced chloroplast proteins in C(4 plants.

  19. Risk assessment for Helicoverpa zea (Lepidoptera: Noctuidae) resistance on dual-gene versus single-gene corn.

    Science.gov (United States)

    Edwards, Kristine T; Caprio, Michael A; Allen, K Clint; Musser, Fred R

    2013-02-01

    Recent Environmental Protection Agency (EPA) decisions regarding resistance management in Bt-cropping systems have prompted concern in some experts that dual-gene Bt-corn (CrylA.105 and Cry2Ab2 toxins) may result in more rapid selection for resistance in Helicoverpa zea (Boddie) than single-gene Bacillus thuringiensis (Bt)-corn (CrylAb toxin). The concern is that Bt-toxin longevity could be significantly reduced with recent adoption of a natural refuge for dual-gene Bt-cotton (CrylAc and Cry2Ab2 toxins) and concurrent reduction in dual-gene corn refuge from 50 to 20%. A population genetics framework that simulates complex landscapes was applied to risk assessment. Expert opinions on effectiveness of several transgenic corn and cotton varieties were captured and used to assign probabilities to different scenarios in the assessment. At least 350 replicate simulations with randomly drawn parameters were completed for each of four risk assessments. Resistance evolved within 30 yr in 22.5% of simulations with single-gene corn and cotton with no volunteer corn. When volunteer corn was added to this assessment, risk of resistance evolving within 30 yr declined to 13.8%. When dual-gene Bt-cotton planted with a natural refuge and single-gene corn planted with a 50% structured refuge was simulated, simultaneous resistance to both toxins never occurred within 30 yr, but in 38.5% of simulations, resistance evolved to toxin present in single-gene Bt-corn (CrylAb). When both corn and cotton were simulated as dual-gene products, cotton with a natural refuge and corn with a 20% refuge, 3% of simulations evolved resistance to both toxins simultaneously within 30 yr, while 10.4% of simulations evolved resistance to CrylAb/c toxin.

  20. Compost and Crude Humic Substances Produced from Selected Wastes and Their Effects on Zea mays L. Nutrient Uptake and Growth

    Directory of Open Access Journals (Sweden)

    Perumal Palanivell

    2013-01-01

    Full Text Available Production of agriculture and timber commodities leads generation of enormous quantity of wastes. Improper disposal of these agroindustrial wastes pollutes the environment. This problem could be reduced by adding value to them. Therefore, a study was carried out to analyse and compare the nutrients content of RS, RH, SD, and EFB of composts and crude humic substances; furthermore, their effect on growth, dry matter production, and nutrient uptake for Zea mays L., and selected soil chemical properties were evaluated. Standard procedures were used to analyze humic acids (HA, crude fulvic acids (CFA, crude humin (CH, soil, dry matter production and nutrient uptake. Sawdust and RS compost matured at 42 and 47 days, respectively, while RH and EFB composts were less matured at 49th day of composting. Rice straw compost had higher ash, N, P, CEC, HA, K, and Fe contents with lower organic matter, total organic carbon, and C/N and C/P ratios. The HA of sawdust compost showed higher carbon, carboxylic, K, and Ca contents compared to those of RS, RH, and EFB. Crude FA of RS compost showed highest pH, total K, Ca, Mg, and Na contents. Crude humin from RS compost had higher contents of ash, N, P, and CEC. Rice straw was superior in compost, CFA, and CH, while sawdust compost was superior in HA. Application of sawdust compost significantly increased maize plants’ diameter, height, dry matter production, N, P, and cations uptake. It also reduced N, P, and K based chemical fertilizer use by 90%. Application of CH and the composts evaluated in this study could be used as an alternative for chemical fertilizers in maize cultivation.

  1. Estimation of heterosis for grain yield and quality traits in sweet corn (Zea mays var. sacharata L.

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    M. C. Dagla, R. N. Gadag, O. P. Sharma, Narendra Kumar

    2014-12-01

    Full Text Available The study was carried out to estimate heterosis for yield and biochemical quality traits in sweet corn (Zea mays var. sacharata crosses. Forty five hybrids using diallel mating design excluding reciprocals were generated. These hybrids along with their ten parents and one standard check (Madhuri were grown at IARI, New Delhi during kharif-2008 in randomized block design (RBD. Estimation of heterosis over standard check (HSC ‘Madhuri’, mid-parent (HMP, and better parent (HBP was calculated. The significant heterosis over standard check for grain yield was found in five crosses, and for sugar content in twelve crosses out of forty five. The HMP for grain yield was found in eighteen crosses and for sugar content in nine crosses. The HMP for grain yield and sugar content was found in IPSA-6134 × IPSA-6141, IPSA-6135 × IPSA-6136, and IPSA-6141 × IPSA-6142. One cross IPSA-6137 × IPSA-6139 showed HMP for protein content and grain yield. One cross IPSA-6136 × IPSA-6139 showed HMP for sugar content and protein content. The HBP was observed in IPSA-6135 × IPSA-6136, IPSA-6136 × IPSA-6139, IPSA-6138 × IPSA-6141, IPSA-6139 × IPSA-6140 and IPSA-6140 × IPSA-6141 for sugar content and IPSA-6134 × IPSA-6137, IPSA-6134 × IPSA-6141, IPSA-6134 × IPSA-6142, IPSA-6135 × IPSA-6139, IPSA-6140 × IPSA-6142, and IPSA-6141 × IPSA-6142 for grain yield. Two crosses IPSA-6135 × IPSA-6136 and IPSA-6141 × IPSA-6142 have the HBP for grain yield and sugar content. One cross IPSA 6137 × IPSA 6139 showed the HBP for protein and grain yield.

  2. Characterization of photosynthetic performance during senescence in stay-green and quick-leaf-senescence Zea mays L. inbred lines.

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    Zishan Zhang

    Full Text Available The net photosynthetic rate, chlorophyll content, chlorophyll fluorescence and 820 nm transmission were investigated to explore the behavior of the photosynthetic apparatus, including light absorption, energy transformation and the photoactivities of photosystem II (PSII and photosystem I (PSI during senescence in the stay-green inbred line of maize (Zea mays Q319 and the quick-leaf-senescence inbred line of maize HZ4. The relationship between the photosynthetic performance and the decrease in chlorophyll content in the two inbred lines was also studied. Both the field and laboratory data indicated that the chlorophyll content, net photosynthetic rate, and the photoactivities of PSII and PSI decreased later and slower in Q319 than in HZ4, indicating that Q319 is a functional stay-green inbred line. In order to avoid the influence of different development stages and environmental factors on senescence, age-matched detached leaf segments from the two inbred lines were treated with ethephon under controlled conditions to induce senescence. The net photosynthetic rate, light absorption, energy transformation, the activities of PSII acceptor side and donor side and the PSI activities decreased much slower in Q319 than in HZ4 during the ethephon-induced senescence. These results suggest that the retention of light absorption, energy transformation and activity of electron transfer contribute to the extended duration of active photosynthesis in Q319. Although the chlorophyll content decreased faster in HZ4, with decrease of chlorophyll content induced by ethephon, photosynthetic performance of Q319 deteriorated much more severely than that of HZ4, indicating that, compared with Q319, HZ4 has an advantage at maintaining higher photosynthetic activity with decrease of chlorophyll although HZ4 is a quick-leaf-senescence inbred line. We conclude that attention should be paid to two favorable characteristics in breeding long duration of active

  3. Cotranscription and processing of 23S, 4.5S and 5S rRNA in chloroplasts from Zea mays.

    OpenAIRE

    Strittmatter, G; Kössel, H.

    1984-01-01

    The termini of rRNA processing intermediates and of mature rRNA species encoded by the 3' terminal region of 23S rDNA, by 4.5S rDNA, by the 5' terminal region of 5S rDNA and by the 23S/4.5S/5S intergenic regions from Zea mays chloroplast DNA were determined by using total RNA isolated from maize chloroplasts and 32P-labelled rDNA restriction fragments of these regions for nuclease S1 and primer extension mapping. Several processing sites detectable by both 3' and 5' terminally labelled probes...

  4. Pyramiding the disease resistant genes to southern rust and stalk rot in maize(Zea mays L.) with marker-assisted selection

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Southern corn rust(SCR) caused by Puccinia polysora Underw and maize stalk rot caused by Pythium inflatum Matthews(MSR-2) are two destructive diseases of maize(Zea mays L.) in China.Our previous studies indicated that maize inbred line Qi319 is highly resistant to SCR but susceptible to MSR-2,while inbred line 1145 is highly resistant to MSR-2 but susceptible to SCR.The SCR resistant gene(RppQ) in Qi319 and MSR-2 resistant gene(Rpi1) in 1145 have been mapped on chromosome 10 and 4 respectively.In this resea...

  5. USO DE TRAMPAS DE LUZ FLUORESCENTE PARA EL MANEJO DE LA GALLINA CIEGA (COLEOPTERA: MELOLONTHIDAE) EN MAÍZ (Zea mays L.)

    OpenAIRE

    Agustín Aragón-García; Christian D. Nochebuena-Trujillo; Miguel Á. Morón; Jesús F. López-Olguín

    2008-01-01

    La gallina ciega (Phyllophaga ravida Blanch) es la plaga que causa mayores daños al sistema radical del maíz (Zea mays) en las zonas maiceras del estado de Puebla. En la región centro del estado, el método de control más utilizado es el químico, lo que genera problemas ambientales, por lo que se requiere buscar alternativas de control. El objetivo del presente estudio fue reducir la población de P. ravida en maíz mediante trampas de luz fluorescente negra. Las trampas se distribuyeron en una ...

  6. Resistencia de Variedades e Híbridos de Maíz (Zea mays) a Sporisorium reilianum y su Rendimiento de Grano

    OpenAIRE

    Jesús Gaudencio Aquino Martínez; Alberto Sánchez Flores; Andrés González Huerta; Jesús Ricardo Sánchez Pale

    2011-01-01

    En Metepec, Mexico, durante 2006 se comparo la respuesta al carbón de la espiga Sporisorium reilianum, de 35 variedades e hibridos comerciales de maiz (Zea mays L.). Semilla de 36 genotipos, sin inocular (ensayo 1, E1) o inoculada con S. reilianum (ensayo 2, E2), se sembro en un diseno de bloques al azar con tres repeticiones (parcela util de 16 m2), con el fin de identificar genotipos resistentes al patogeno. A los 245 días después de la siembra (dds), se obtuvieron los siguientes resultados...

  7. Competencia entre Zea mays y Sorghum halepense por agua edáfica y su incidencia en el intercambio gaseoso foliar

    OpenAIRE

    Acciaresi,H.A.; M.S. Zuluaga; M. E. Yanniccari; J. J. Guiamet

    2012-01-01

    La alta estabilidad productiva en ambientes con restricciones hídricas se ha vinculado a la habilidad de conservación del agua por parte de los cultivos. Sin embargo, diferentes especies de malezas, bajo competencia hídrica realizan un uso ineficiente de la misma. Con el objetivo de determinar la estrategia de consumo de agua que poseen Zea mays y Sorghum halepense bajo dos situaciones de disponibilidad hídrica edáfica y trabajando con plantas en contenedores, se estudió la evolución...

  8. Puente pretensado sobre el Guadarrama. Villalba

    Directory of Open Access Journals (Sweden)

    Páez, A.

    1958-12-01

    Full Text Available En este artículo se describe y comenta la solución dada al puente de hormigón pretensado sobre el río Guadarrama, primero de los construidos mediante dovelas prefabricadas y solidarizadas después, mediante el pretensado de la armadura longitudinal.

  9. Un nuevo libro sobre Juan de Castellanos

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    Alberto Miramón

    1979-02-01

    Full Text Available El Centro de Historia del Táchira ha auspiciado la publicación, por la Editorial Kelly de Bogotá, del segundo libro que monseñor Mario Germán Romero ha escrito sobre la vida y obra, tan apasionante ambas, de don Joan de Castellanos

  10. O pensamento de Marx sobre a subjetividade

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    Eduardo F. Chagas

    2013-08-01

    Full Text Available O pensamento de Karl Marx sobre a subjetividade humana é pouco conhecido e divulgado na língua portuguesa, e, no Brasil, particularmente, carece ainda de um estudo amplo, explícito e sistemático. Meu artigo pretende esboçar uma reflexão mais completa de sua filosofia sobre a subjetividade humana, insistindo não somente na crítica, mas também, e especialmente, na compreensão da referida questão, a partir de uma leitura imanente e estrutural de suas obras, no original. Vale ainda ressaltar que minha investigação se apoia na conexão entre subjetividade e objetividade, entre sujeito e objeto, inquirindo se há um determinismo da objetividade sobre a subjetividade, ou seja, se essas duas determinações são contraditórias no interior do pensamento marxiano, comprometendo, pois, as suas reflexões acerca da crítica à filosofia especulativa de Hegel e ao empirismo da economia clássica, ou se, na verdade, tal conexão é o segredo recôndito de sua filosofia sobre a subjetividade humana.

  11. Los derechos reales sobre cosa ajena

    OpenAIRE

    Panero Oria, Patricia

    2011-01-01

    Esta presentación cierra la serie de presentaciones que sa han realizado sobre los Derechos reales, según el Plan Docente seguido en la Facultad de Derecho de la Universidad de Barcelona, y que sirven de guía para el estudio de la materia.

  12. Las fuentes cristianas sobre Jesús

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    Melero Martínez, J.M.

    2010-01-01

    Full Text Available El artículo es una presentación de las fuentes históricas sobre Jesús de Nazaret: fuentes sinópticas, fuente Q, fuentes afines a la gnosis, fragmentos de evangelio con material sinóptico o joánico, evangelios judeocristianos y otras fuentes.

  13. Yield stability in maize (Zea mays L. and correlations among the parameters of the Eberhart and Russell, Lin and Binns and Huehn models

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Scapim

    2000-06-01

    Full Text Available Assessment of the stability and adaptability of a genotype to different environments is useful for recommending cultivars for known conditions of cultivation and should be a requirement in breeding programs. Twenty maize (Zea mays L. cultivars were tested at eight locations in Minas Gerais by the National Center for Maize and Sorghum Research (CNPMS of the Brazilian Enterprise for Agricultural Research (EMBRAPA for two years. The experiments involved a randomized complete block design in which three procedures were used to analyze cultivar stability and adaptability. The level of association among the parameters obtained by the three methods was assessed using Spearman's rank correlation. Hybrids 'DINA 170', 'G-96C', 'C 505', 'DINA 70' and 'C 435' had a mean yield greater than 6,000 kg/ha. Eberhart and Russell's regression coefficient (betai was negative and correlated significantly (P or = 0.05, but correlated positively with Si(1 (P O conhecimento sobre a estabilidade e adaptabilidade de comportamento de genótipos contém informações muito úteis para a recomendação de cultivares para condições de cultivo conhecidas a priori, de modo que a avaliação da resposta dos genótipos às variações ambientais deve ser etapa obrigatória em programas de melhoramento. Para caracterizar 20 cultivares de milho, foram realizados dez ensaios (oito localidades do Estado de Minas Gerais, em dois anos no delineamento de blocos ao acaso, pelo Centro Nacional de Pesquisa de Milho e Sorgo (CNPMS da Empresa Brasileira de Pesquisa Agropecuária (Embrapa. Três procedimentos estatísticos foram adotados para a análise da estabilidade e adaptabilidade dos cultivares e avaliou-se o grau de associação entre os parâmetros dos três métodos por meio da correlação classificatória de Spearman. 'DINA 170', 'G-96C', 'C 505', 'DINA 70' e 'C 435' destacaram-se com produtividades médias superiores a 6.000 kg/ha. O coeficiente de regressão (betai de Eberhart

  14. β-d-Glucan Antibodies Inhibit Auxin-Induced Cell Elongation and Changes in the Cell Wall of Zea Coleoptile Segments 1

    Science.gov (United States)

    Hoson, Takayuki; Nevins, Donald J.

    1989-01-01

    Antiserum was raised against the Avena sativa L. caryopsis β-d-glucan fraction with an average molecular weight of 1.5 × 104. Polyclonal antibodies recovered from the serum after Protein A-Sepharose column chromatography precipitated when cross-reacted with high molecular weight (1→3), (1→4)-β-d-glucans. These antibodies were effective in suppression of cell wall autohydrolytic reactions and auxin-induced decreases in noncellulosic glucose content of the cell wall of maize (Zea mays L.) coleoptiles. The results indicate antibody-mediated interference with in situ β-d-glucan degradation. The antibodies at a concentration of 200 micrograms per milliliter also suppress auxin-induced elongation by about 40% and cell wall loosening (measured by the minimum stress-relaxation time of the segments) of Zea coleoptiles. The suppression of elongation by antibodies was imposed without a lag period. Auxin-induced elongation, cell wall loosening, and chemical changes in the cell walls were near the levels of control tissues when segments were subjected to antibody preparation precipitated by a pretreatment with Avena caryopsis β-d-glucans. These results support the idea that the degradation of (1→3), (1→4)-β-d-glucans by cell wall enzymes is associated with the cell wall loosening responsible for auxin-induced elongation. PMID:16666935

  15. beta-d-Glucan Antibodies Inhibit Auxin-Induced Cell Elongation and Changes in the Cell Wall of Zea Coleoptile Segments.

    Science.gov (United States)

    Hoson, T; Nevins, D J

    1989-08-01

    Antiserum was raised against the Avena sativa L. caryopsis beta-d-glucan fraction with an average molecular weight of 1.5 x 10(4). Polyclonal antibodies recovered from the serum after Protein A-Sepharose column chromatography precipitated when cross-reacted with high molecular weight (1-->3), (1-->4)-beta-d-glucans. These antibodies were effective in suppression of cell wall autohydrolytic reactions and auxin-induced decreases in noncellulosic glucose content of the cell wall of maize (Zea mays L.) coleoptiles. The results indicate antibody-mediated interference with in situ beta-d-glucan degradation. The antibodies at a concentration of 200 micrograms per milliliter also suppress auxin-induced elongation by about 40% and cell wall loosening (measured by the minimum stress-relaxation time of the segments) of Zea coleoptiles. The suppression of elongation by antibodies was imposed without a lag period. Auxin-induced elongation, cell wall loosening, and chemical changes in the cell walls were near the levels of control tissues when segments were subjected to antibody preparation precipitated by a pretreatment with Avena caryopsis beta-d-glucans. These results support the idea that the degradation of (1-->3), (1-->4)-beta-d-glucans by cell wall enzymes is associated with the cell wall loosening responsible for auxin-induced elongation.

  16. Flutuação Populacional e Parasitismo de Ovos de Spodoptera frugiperda e Helicoverpa zea em milho pulverizado com extratos vegetais e Metarhizium anisopliae

    Directory of Open Access Journals (Sweden)

    Jaqueline Ramos de Freitas

    2010-10-01

    Full Text Available We evaluated the effect of plant extracts and Metarhizium anisopliae on population and parasitism of eggs of Spodoptera frugiperda and Helicoverpa zea in corn planted at two spacings. The research was conducted at the Agricultural School "Assis Chateaubriand" in Laguna Seca, PB, and Laborat6rio of Entomology at the Center for Integrated Pest Management / UEPB in Campina Grande-PB. Corn was planted in an area of 500m2, in spacing: (I 0,8 m x 0,4 m, and (II 0,4 m x 0,4 m, with one or two plants per hole, respectively. The treatments consisted of: 1 water as a control, 2 M. anisopliae (100 g 10 L-1 water, 3 Extract of Momordica charantia (50 ml L-1 water, 4 M. anisopliae (10 g L-1 water + water extract of M. charantia (50 ml L-1 water, 5 M. anisopliae (10 g L-1 water + cassava (Manihot esculenta Crantz (50 ml L-1 water. According to the results, no significant difference between treatments to control spacing I S. frugiperda egg, which was due, probably, late spraying, when 100% of the plants were attacked. The treatments also not efficient to control H zea eggs, recommending further studies to determine the concentration and dosage most appropriate for controlling these pests.

  17. Efeitos de citocininas sobre a anatomia foliar e o crescimento de Annona glabra L. durante o cultivo in vitro e ex vitro Effects of cytokinins on the leaf anatomy and growth of Annona glabra L. during in vitro and ex vitro culture

    Directory of Open Access Journals (Sweden)

    Lenaldo Muniz de Oliveira

    2008-08-01

    Full Text Available O efeito de diferentes fontes de citocininas durante o cultivo in vitro de A. glabra sobre características anatômicas de folhas e crescimento das plantas foi avaliado neste trabalho. BAP (6-benzilaminopurina e KIN (cinetina induziram aumento na espessura do mesofilo, enquanto que ZEA (zeatina promoveu aumento na densidade e no índice estomático e no desenvolvimento do sistema vascular de folhas. A utilização de KIN e BAP proporcionou maior desenvolvimento e taxa de sobrevivência das plantas durante as fases de enraizamento e aclimatização.The effect of different sources of cytokinins during the in vitro cultivation of A. glabra on anatomical characteristics of leaves and plant growth was evaluated in this work. BAP (6-benzilaminopurine and KIN (kinetin induced an increase in leaf mesophyll thickness, while the ZEA (zeatin promoted an increase in density and stomatic index and development of leaves vascular system. The utilization of KIN and BAP improved higher plant development and survival rate during the acclimatization and rooting phases.

  18. Effects of Zinc Deficiency and Drought on Plant Growth and Metabolism of Reactive Oxygen Species in Maize (Zea mays L.)

    Institute of Scientific and Technical Information of China (English)

    WANG Hong; JIN Ji-yun

    2007-01-01

    The combinative effects of applied zinc (Zn) and soil moisture on the plant growth, Zn uptake, and the metabolism of reactive oxygen species (ROS) in maize (Zea mays L.) plants were examined through two pot experiments under greenhouse conditions. Maize variety Zhongdan 9409 was used. In experiment 1, maize plants were grown in cumulic cinnamon soil with five Zn treatments (0, 3.0, 9.0, 27.0, and 81.0 mg Zn kg-1 soil). Three treatments of soil moisture including serious drought, mild drought, and adequate water supply were set at 30-35 %, 40-45 %, and 70-75 % (w/w) of soil saturated water content, respectively. Soil saturated water content was 36% (w/w). The dry matter weights of shoots were enhanced by Zn application and adequate water supply. There was no apparent difference in plant growth among Zn application rates from 3.0 to 81.0 mg Zn kg-1 soil. The increases of plant growth and Zn uptake due to Zn application were found more significant under well-watered condition than under drying condition. In experiment 2, two levels of Zn (0 and 5.0 mg Zn kg-1 soil) and soil moisture regimen (40-45 % and 70-75 % of soil saturated water content, respectively) were set. Zn deficiency or water stress resulted in higher concentrations of O2-· and malondiadehyde in the first fully expanded leaves.Zn deficiency lowered the activity of superoxide dismutase (SOD, EC 1.15.1.1) in leaves. Drought stress increased SOD activity in leaves regardless of Zn supply. The activity of guaiacol peroxidase (POD, EC1.11.1.11) was found to be enhanced by Zn supply only in well-watered leaves. Zinc deficiency or water stress had little effect on the activity of catalase (CAT, EC 1.11.1.6). The higher ROS level in early maize leaves due to water stress seemed not to be alleviated or lowered partially by Zn application. However, Zn fertilizer was recommended to apply to maize plants irrigated or supplied with adequate water, otherwise Zn deficiency would reduce the water use for plant biomass

  19. Investigating the response of tropical maize (Zea mays L.) cultivars against elevated levels of O3 at two developmental stages.

    Science.gov (United States)

    Singh, Aditya Abha; Agrawal, S B; Shahi, J P; Agrawal, Madhoolika

    2014-10-01

    Tropospheric ozone (O3) concentrations are rising in Indo-Gangetic plains of India, causing potential threat to agricultural productivity. Maize (Zea mays L.) is the third most important staple crop at global level after rice and wheat. Two high yielding cultivars of Indian maize (HQPM1-quality protein maize and DHM117-normal/non quality protein maize) were exposed to two levels of elevated O3 above the ambient level (NFC) viz. NFC + 15 ppb O3 (NFC + 15) and NFC + 30 ppb O3 (NFC + 30) using open top chambers under field conditions. The study was conducted to evaluate the biochemical responses of two cultivars at different developmental stages leading to change in yield responses. Initially at lower O3 dose, photosynthetic pigments showed an increase but reduction at later stage, while higher dose caused a decline at both the stages of sampling. Levels of superoxide radical (O2 (-)) and hydrogen peroxide (H2O2) significantly increased and contributed to lipid peroxidation at elevated O3. Histochemical localization assay of O2 (-) and H2O2 showed that guard cells of stomata and cells around trichomes took deeper stain at elevated O3 reflecting more formation of reactive oxygen species. Secondary metabolites like total phenol, flavonoids and anthocyanin pigments also increased in plants under O3 stress. Enzymatic antioxidants were triggered in both the cultivars due to elevated O3, while induction of non-enzymatic antioxidants was more in HQPM1. Native PAGE analysis also showed that SOD, POX, CAT, APX and GPX were stimulated at elevated O3 concentrations compared to NFC. SDS-PAGE showed reductions of major photosynthetic proteins with higher decrease in DHM117. Principal Component Analysis showed that both the cultivars showed differential response against O3 at two developmental stages. HQPM1 maintained the analogous defense strategy at both the sampling stages while DHM117 showed variable response. Overall metabolic induction of antioxidants related to defense was

  20. Genome-Wide Identification and Characterization of microRNAs in Developing Grains of Zea mays L.

    Science.gov (United States)

    Li, Dandan; Liu, Zongcai; Gao, Lei; Wang, Lifang; Gao, Meijuan; Jiao, Zhujin; Qiao, Huili; Yang, Jianwei; Chen, Min; Yao, Lunguang; Liu, Renyi; Kan, Yunchao

    2016-01-01

    The development and maturation of maize kernel involves meticulous and fine gene regulation at transcriptional and post-transcriptional levels, and miRNAs play important roles during this process. Although a number of miRNAs have been identified in maize seed, the ones involved in the early development of grains and in different lines of maize have not been well studied. Here, we profiled four small RNA libraries, each constructed from groups of immature grains of Zea mays inbred line Chang 7-2 collected 4-6, 7-9, 12-14, and 18-23 days after pollination (DAP). A total of 40 known (containing 111 unique miRNAs) and 162 novel (containing 196 unique miRNA candidates) miRNA families were identified. For conserved and novel miRNAs with over 100 total reads, 44% had higher accumulation before the 9th DAP, especially miR166 family members. 42% of miRNAs had highest accumulation during 12-14 DAP (which is the transition stage from embryogenesis to nutrient storage). Only 14% of miRNAs had higher expression 18-23 DAP. Prediction of potential targets of all miRNAs showed that 165 miRNA families had 377 target genes. For miR164 and miR166, we showed that the transcriptional levels of their target genes were significantly decreased when co-expressed with their cognate miRNA precursors in vivo. Further analysis shows miR159, miR164, miR166, miR171, miR390, miR399, and miR529 families have putative roles in the embryogenesis of maize grain development by participating in transcriptional regulation and morphogenesis, while miR167 and miR528 families participate in metabolism process and stress response during nutrient storage. Our study is the first to present an integrated dynamic expression pattern of miRNAs during maize kernel formation and maturation.

  1. Field inoculation of arbuscular mycorrhiza on maize (Zea mays L. under low inputs: preliminary study on quantitative and qualitative aspects

    Directory of Open Access Journals (Sweden)

    Emilio Sabia

    2015-03-01

    Full Text Available Arbuscular mycorrhizal symbiosis contributes to the sustainability of soil-plant system. A field experiment was conducted to examine the effect of arbuscular mycorrhiza (AM on quantitative and qualitative performance in forage maize (Zea mays L.. Within the project Sviluppo di modelli zootecnici ai fini della sostenibilità (SOS-ZOOT a trial was conducted at the experimental farm of the Agricultural Research Council in Bella (PZ, located in Basilicata region (Southern Italy at 360 m asl, characterised by an annual rainfall of approximately 650 mm. For spring sowing, two plots of 2500 m2 were used, one sown with seeds inoculated with AM (M, 1.0 kg/ha, and the other one with non-inoculated seeds (NM. After 120 days after sowing, when plants showed 30% dry matter, five replicates of 1 m2 per plot were used to estimate dry matter yield (DMY, while half plot was dedicated to the assessment of grain production. For each replicate, three representative plants were considered; each plant was measured for height and was divided into leaves, stem and ear. For each plot, the following constituents were determined: crude protein, ash, ether extract, crude fibre (CF, fractions of fibre [neutral detergent (NDF, acid detergent fibre (ADF and sulphuric acid lignin] and phosphorus (P. Throughout the period of plants’ growth, no herbicides, organic or inorganic fertilisation, and irrigation water were distributed. The preliminary results revealed a significant effect of AM inoculation on forage maize DMY, P content in the whole plant, into the leaves and on the quality of steam. The M thesis showed a significant increase in terms of DMY in comparison with the NM thesis: 21.2 vs 17.9 t/ha (P<0.05. The mycorrhized whole plants [0.22 vs 0.17% dry matter (DM, P<0.05] and leaves (0.14 vs 0.09% DM, P<0.05 showed an increased P content. The stems of M plants showed a content of CF, NDF, ADF and Ash significantly lower compared with NM plants. No significant

  2. Pertumbuhan, Hasil dan Analisis Produksi Tanaman Jagung (Zea mays L. yang Diperlakukan dengan Pupuk Organik dan Biourin di Lahan Kering

    Directory of Open Access Journals (Sweden)

    I MADE SUKADANA

    2015-09-01

    Full Text Available Growth, Yield, and Production Analysis of Maize (Zea mays L. Treated by Organic Fertilizer and Cow Biourine in Dry Land Maize productivity in Bali is still low at around 3.4 ton/ha. Low soil fertility is one of the factors contributable to the low productivity of maize. Soil condition at the research field has low level of fertility with low levels of nitrogen and C-organic. This research aims at finding out the impact of organic fertilizers and cow biourine to the growth and yield of maize in dry land and to analyze it gross margin. Experiment was designed with randomized block design (RBD with two factors and four replications. The dosage of the first factor namely without organic fertilizer, cow organic fertilizer 15 tonnes/ha and worm casting fertilizer 15 tonnes/ha, whereas dosage of cow biourine namely 0 liter, 1.000 liters, 2.000 liters and 3.000 liters/ha respectively for the second factor. The research results show that there is highly significant interaction (p<0.01 between organic fertilizers and cow biourine to the number of leaves aged at 21, 35, 49 and 63 dap, trunk diameter, dry matter weight/plant, number of cobs/plant, and harvest index, however it shows significant interaction (p<0.05 to leave area index (LAI at age 35 dap and soil pH at harvest. The combination of worm casting fertilizer of 15 tonnes/ha with cow biourine 2.000 liters/ha resulted in the highest dry weight of seed/ha to 4,09 tonnes/ha, an increase of 69,71% compared to no fertilizer. The relationship between organic fertilizer and cow biourine to the dry matter yield follows a quadratic pattern, hence 15 tonnes/ ha worm casting fertilizer and 2000 liters/ha of cow biourine resulted in optimum yield from this research. Result from the gross margin analysis shows that revenue received at Rp 8.7935 million based on the price of dry shelled corn at Rp 2.150/kg does not cover the high variable cost at Rp 26.664,500.

  3. Ameliorative Effects of Brassinosteroid on Excess Manganese-Induced Oxidative Stress in Zea mays L.Leaves

    Institute of Scientific and Technical Information of China (English)

    WANG Hai-hua; FENG Tao; PENG Xi-xu; YAN Ming-li; ZHOU Ping-lan; TANG Xin-ke

    2009-01-01

    Manganese (Mn) is becoming an important factor limiting crop growth and yields especially on acid soils.The present study was designed to explore the hypothesis that brassinosteroid application can enhance the tolerance of maize(Zea mays L.)to Mn stress and if so,whether or not the mechanism underlying involves regulation of antioxidative metabolism in leaves.The effects of 24-epibrassinosteroid(EBR)on the growth,photosynthesis,water status,lipid peroxidation,accumulation of reactive oxygen species,and activities or contents of antioxidant defense system in maize plants under Mn stress were investigated by a pot experiment.At supplemented Mn concentrations of 150-750 mg kg-1 soil,the growth of plants was inhibited in a concentration-dependent manner.The semi-lethal concentration was 550 mg Mn kg-1 soil.Foliage application with 0.1 mg L-1 EBR significantly reduced the decrease in dry mass,chlorophyll content,photosynthetic rate,leaf water content,and water potential of plants grown in the soil spiked with 550 mg kg-1 Mn.The oxidative stress caused by excess Mn,as reflected by the increase in malondialdehyde (MDA) content and lipoxygenase (LOX,EC 1.13.11.12) activity,accumulation of superoxide radical and H2O2,was greatly decreased by EBR treatment.Further investigations revealed that EBR application enhanced the activities ofsuperoxide dismutase (SOD,EC 1.15.1.1),peroxidase (POD,EC 1.11.1.7),catalase (EC 1.11.1.6),ascorbate peroxidase (APX,EC 1.11.1.11),dehydroascorbate reductase (DHAR,EC1.8.5.1),and glutathione reductase (GR,EC 1.6.4.2),and the contents of reduced ascorbate and glutathione,compared with the plants without EBR treatment.It iS concluded that the ameliorative effects of EBR on Mn toxicity are due to the upregulation of antioxidative capacity in maize under Mn stress.

  4. Observaciones sobre didáctica

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    Alfonso Tamayo Valencia

    2014-02-01

    Full Text Available  En el presente artículo, a partir de la conceptualización sobre didáctica y enseñanza, se plantean sus posibilidades en la educación superior, especialmente cuando reflexionamos en las prácticas de enseñanza desde un saber hacer que supere el hacer de esquemas tácitos y espontáneos que caracteriza en buena parte docencia universitaria. Desde esta perspectiva se aboga por la renovación de la concepción de la didáctica desde una postura epistemológica y psicológica sobre la manera como se construye el conocimiento.

  5. Sobre lectura y escritura en Chile

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    Grínor Rojo

    2011-11-01

    Full Text Available Los estudios de los últimos años realizados en Chile sobre lectura, competencia de lectura y lectura de noticias sobre política, revelan valores negativos que rondan el 50. Estos datos, a los que se suman los cuarenta millones de analfabetos en América Latina, están en la base del rechazo en este artículo de la afirmación de la muerte del libro y de la frívola fe en el reemplazo del libro por el uso de las tecnologías de la información y la comunicación (llenar de computadoras las escuelas, insistiendo en cambio en atender seriamente a los lazos entre razón, libro y lectura en el desarrollo individual y de la sociedad

  6. Representaciones sociales juveniles sobre la democracia

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    Álvaro Díaz Gómez

    2005-01-01

    Full Text Available El presente artículo da cuenta de una parte de los resultados obtenidos en la investigación “representaciones sociales juveniles sobre la democracia y la multiculturalidad”. Se desarrolló desde la perspectiva metodológica de la Investigación Acción Participante, proceso dentro del cual, se aplicó un cuestionario conformado por nueve preguntas, divididas en tres bloques temáticos que permitieron conocer las representaciones sociales de un grupo de veinticinco jóvenes, sobre la democracia –aspecto que se reporta en este texto– la ciudadanía y la multiculturalidad a partir de tres dimensiones: significado, vivencias y condiciones de la democracia.

  7. Sobre lectura y escritura en Chile

    OpenAIRE

    Grínor Rojo

    2011-01-01

    Los estudios de los últimos años realizados en Chile sobre lectura, competencia de lectura y lectura de noticias sobre política, revelan valores negativos que rondan el 50. Estos datos, a los que se suman los cuarenta millones de analfabetos en América Latina, están en la base del rechazo en este artículo de la afirmación de la muerte del libro y de la frívola fe en el reemplazo del libro por el uso de las tecnologías de la información y la comunicación (llenar de computadoras las escuelas), ...

  8. Radiaciones ionizantes y efectos sobre la materia

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    Sandra Magaly Medina Araujo

    2002-01-01

    Full Text Available Las radiaciones ionizantes, además, de tener muchas aplicaciones benéficas tanto en el campo industrial como en los organismos vivientes, presentan también muchos efectos nocivos que se deben evitar, sobre todo cuando se trata de fuentes artificiales con las que pueden presentarse abusos en su utilización, especialmente en la parte clínica. Este artículo, el primero de una serie de divulgaciones acerca del tema, pretende dar a conocer las características y efectos sobre la materia, de las mencionadas radiaciones, así como algunas recomendaciones acerca del manejo y tralAS, tamiento de dichas radiaciones

  9. Monografía FOMIN sobre Remesas

    OpenAIRE

    Inter-American Development Bank; Analistas Financieros Internacionales (AFI)

    2009-01-01

    Consultoria realizada por Analistas Financieros Internacionales para Fondo Multilateral de Inversiones sobre: Flujos de remesas a América Latina: Características del mercado de remesas y sus actores principales. Aspectos regulatorios relevantes para facilitar el rol de las remesas como instrumento de desarrollo. Descripción de la cartera de proyectos FOMIN y su nueva estrategia en el Cluster de Remesas.

  10. Cumbre Mundial sobre Desarrollo Social. Copenhague

    OpenAIRE

    Abellán García, Antonio

    1995-01-01

    La Asamblea General de Naciones Unidas adoptó en 1992 la decisión De convocar una Cumbre Mundial sobre Desarrollo Social para afrontar los problemas de pobreza, desempleo e integración social. La Cumbre tuvo lugar en marzo de 1995, en Copenhague, y se desarrolló en tres partes: Plenario, Comité Principal y Cumbre de Jefes de Estado o Gobierno

  11. Reflexiones sobre el concepto de justicia

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    Víctor C. Pascual Planchuelo

    2005-06-01

    Full Text Available Este ensayo constituye una reflexión sobre el concepto de Justicia. No se centra, como tantos estudios al respecto, en el plano teórico y metafísico, sino que atiende problemas de mayor actualidad: la opinión de los ciudadanos, la postura de los profesionales y otros asuntos controvertidos del ámbito del Derecho.

  12. Sobre la felicidad y la ataraxia

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    Alberto Londoño Alvarez

    1969-09-01

    Full Text Available Muy pocos lectores, seguramente, no han tomado en momentos de crisis nerviosas, de desarreglos emocionales, de intranquilidad y angustia, alguna de las tantas drogas que se conocen con el mote genérico de "ataráxicos", de "tranquilizantes". Pues bien, hablemos un poco sobre este tema, sus antecedentes históricos y filosóficos y lo que para los griegos clásicos significaba el vocablo "ataraxia".

  13. Stem characteristics of two forage maize (Zea mays L.) cultivars varying in whole plant digestibility. II. Relation between in vitro rumen fermentation characteristics and anatomical and chemical features within a single internode

    NARCIS (Netherlands)

    Boon, E.J.M.C.; Engels, F.M.; Struik, P.C.; Cone, J.W.

    2005-01-01

    Internode 7 of the stem of two forage maize (Zea mays L.) cultivars was studied anatomically and chemically at anthesis and subjected to fermentation tests in rumen fluid, using an automated gas production system. For anatomical studies internode 7 was sectioned at the top, middle and base. For chem

  14. Stem characteristics of two forage maize (Zea mays L.) cultivars varying in whole plant digestibility. IV. Changes during the growing season in anatomy and chemical composition in relation to fermentation characteristics of a lower internode

    NARCIS (Netherlands)

    Boon, E.J.M.C.; Struik, P.C.; Engels, F.M.; Cone, J.W.

    2012-01-01

    Improving digestibility of forage maize (Zea mays L.) through breeding is important to optimize the efficiency of ruminant's rations. It can partly be achieved by improving the digestibility of stem tissue, a genetically complex and diverse trait changing drastically during the growing season. We tr

  15. Efeitos do sistema de plantio e da consorciação soja-milho sobre artrópodes capturados no solo

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    Cividanes Francisco Jorge

    2002-01-01

    Full Text Available O objetivo deste estudo foi avaliar os efeitos do plantio direto e da consorciação soja [Glycine max (L. Merrill] e milho (Zea mays L. sobre artrópodes que vivem no solo. Os tratamentos constituíram um fatorial 3 x 2 (monocultura de soja, monocultura de milho, consorciação soja-milho x plantio direto, plantio convencional em blocos casualizados com quatro repetições; as amostragens foram efetuadas com armadilhas de solo, durante 1996 a 1998. Resultados estatisticamente significativos em pelo menos uma safra indicaram que o plantio direto foi favorável a predadores, como formigas (Brachymyrmex sp., Camponotus spp. e Ectatomma sp., carabídeos (Metius sp. e aranhas (Lycosidae. A consorciação soja-milho aumentou o número de Acrididae, enquanto a presença do milho favoreceu a ocorrência de Dermaptera em sistemas de consorciação soja-milho.

  16. Relación entre la conductividad eléctrica, pH del agua de remojo, germinación de semillas y crecimiento de plántulas de maíz (Zea mayz L. bajo dos condiciones experimentales

    Directory of Open Access Journals (Sweden)

    Hilmig Viloria

    2011-01-01

    Full Text Available Semillas de maíz (Zea mayz L. de 12 lotes de diferentes años de adquisición se utilizaron para estudiar la relación entre las mediciones de conductividad eléctrica (CE y pH del agua de remojo y la germinación en laboratorio, bajo condiciones normales (CN y uso de envejecimiento acelerado (EA de las semillas. Se utilizó un diseño de bloques completos al azar con cuatro repeticiones, se aplicó un análisis de varianza convencional y las diferencias entre los lotes se detectaron mediante la prueba de mínima diferencia significativa. Los lotes mostraron a los ocho días de evaluación altos porcentajes de germinación en CN y se evidenció el efecto desfavorable sobre la germinación post tratamiento de EA. El peso seco de la parte aérea y de la radícula arrojó diferencias significativas entre los lotes. Los lotes de semillas que mostraron altos porcentajes de germinación en laboratorio, previo EA, presentaron bajos valores de CE, por lo tanto, esta prueba podría ser buen indicativo del comportamiento de semillas de maíz en condiciones extremas o desfavorables de germinación. La prueba de pH no indicó relación directa con la emergencia de las semillas en laboratorio.

  17. ESTUDO SOBRE O IMPACTO DOS PROCESSADORES HOSPEDEIROS

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    Alba S. B. Lopes

    2008-05-01

    Full Text Available Arquiteturas reconfiguráveis são dispositivos de hardware capazes de modificar sua estrutura de hardware de acordo com a aplicação a ser executada. Tais dispositivos surgiram como uma alternativa às soluções de hardware tradicionais na tentativa de equilibrar flexibilidade e desempenho. Uma das principais formas de utilização de arquiteturas reconfiguráveis corresponde a um bloco reconfigurável anexado a um processador hospedeiro. Esse processador é responsável por executar diversas tarefas críticas, incluindo o particionamento hardware/software e indicar o momento do bloco reconfigurável executar. Apesar de existirem diversas propostas de arquiteturas reconfiguráveis na literatura, pouco se estudou sobre o impacto do processador hospedeiro na arquitetura. Nesse contexto, esse artigo apresenta um estudo sobre o impacto do processador hospedeiro no desempenho da arquitetura reconfigurável híbrida. Como estudo de caso foi realizada uma avaliação sobre o uso dos processadores SPARC V8 da Sun Microsystems e Nios II da Altera como processadores hospedeiros da arquitetura reconfigurável híbrida RoSA. O objetivo deste estudo é realizar a comparação entre o desempenho desses processadores e identificar qual deles é o mais adequado para anexar a arquitetura em questão. Os resultados mostraram que foi possível alcançar até 47% de ganho de desempenho com o uso do processador Nios II em comparação ao SPARC V8, indicando o primeiro como mais adequado para a arquitetura RoSA. PALAVRAS-CHAVE: arquiteturas reconfiguráveis, processador hospedeiro, desempenho.

  18. Algunas consideraciones sobre la arquitectura maya

    OpenAIRE

    Cejudo Collera, Mónica; DEPFA UNAM

    2013-01-01

    Con la finalidad de definir las variantes regionales y estilísticas que utilizaron los cons- tructores de la sociedad maya a lo largo de las varias etapas de su desarrollo, se estu- dian, en este artículo, los elementos que conforman las estructuras de la arquitectura maya. El resultado de este proceso de análisis permite ver cómo, a partir de una con- cepción global de la arquitectura y el urbanismo mayas, cada sitio se desarrolló sobre la base de su singularidad.

  19. Debate sobre el agua : punto de partida

    OpenAIRE

    2013-01-01

    A lo largo de este número de la revista encontrarás artículos concretos sobre el uso del agua en la agricultura, las bondades e inconvenientes de diferentes sistemas agrícolas y advertencias a los riesgos de privatización del agua, entre otros. Son temas que, desde la perspectiva de la Soberanía Alimentaria, debemos abordar contestando una pregunta fundamental: para que las y los agricultores puedan alimentar al Planeta y mantenerlo fértil, ¿qué uso y gestión hacemos del Agua?

  20. II Jornadas sobre Emprendimiento Social y Colectivo

    OpenAIRE

    Centro de Investigación en Gestión de Empresas

    2013-01-01

    La línea temática principal del encuentro es el emprendimiento social y colectivo así como las diferentes líneas de investigación de los institutos y centros de la Red relacionadas, como: responsabilidad social, empleo y reincorporación al trabajo, inserción laboral, servicios sociales y dependencia, género, cambios legislativos, utilidad social, medio ambiente, desarrollo local,... Centro de Investigación en Gestión de Empresas (2013). II Jornadas sobre Emprendimiento Social y Colectivo. ...

  1. Modelos mentales sobre el concepto de medida

    OpenAIRE

    Osorio, Andrea Milena

    2009-01-01

    Esta tesis de maestría presenta los resultados de una investigación que tuvo como pretensión comprender la estructura de los modelos mentales sobre el concepto de medida que poseen estudiantes de segundo grado de la educación básica y los estudiantes de formación complementaria (estudiantes que inician la formación docente). Para recoger la información, se emplearon técnicas de recolección de información, la observación y la entrevista semiestructurada, que fueron aplicadas a 8 estudiant...

  2. Modelos mentales sobre el concepto de medida

    OpenAIRE

    Osorio, Andrea Milena; García, Ligia Inés

    2011-01-01

    El objetivo de esta investigación ha sido comprender la estructura de los modelos mentales sobre el concepto de medida que caracteriza a un grupo de estudiantes de segundo grado de básica primaria y de primer año de formación complementaria. En efecto, el interés es identificar los elementos que se dan en los modelos y analizar las posibles relaciones entre dichos elementos. El informe de investigación se encuentra presentado en 7 apartes. La primera parte comprendida por los numerales ...

  3. Apuntes sobre el cultivo del cacao

    OpenAIRE

    Chavarriaga, Eduardo; Ochoa, Horacio

    2013-01-01

    El sombrío constituye uno de los problemas que se presentan en el cultivo del cacao, de necesaria resolución para ayuda del agricultor en su labor al producir tan importante grano. Contribuye a la economía del cultivo un conocimiento amplio de la cuestión que debe preocupar al productor inquiriendo no solamente por lo acostumbrado en la región, sino por lo que en otras partes se conoce sobre el particular, para abandonar un poco el emperismo y hacer una industria cada día más próspera. Co...

  4. Conceptos fundamentales sobre el mantenimiento de edificios

    OpenAIRE

    Juan Miguel Arencibia Fernández

    2007-01-01

    En esta investigación se realiza una profunda búsqueda sobre el tema del Mantenimiento de Edificios donde se abundan diferentes conceptos y criterios de la misma, encontrándose de esta forma los más utilizados métodos a emplear. Luego teniendo en cuenta las clasificación del Mantenimiento de Edificio según los tipos de obras, propietarios del inmueble y el momento que éste se realiza, como los costos de una edificación y su equipamiento a utilizar. Otros de los aspectos a tener en cuenta es l...

  5. Ensayo sobre la melancolía

    Directory of Open Access Journals (Sweden)

    Marta Chacón Salinas

    2013-07-01

    Full Text Available Este trabajo es un intento de delimitar la melancolía del conjunto de los trastornos depresivos y de reflexionar sobre sus características tal como aparecen en el discurso de los melancólicos. Se consideran algunas hipótesis en la línea psicoanalítica freudiana y lacaniana (Lambottc, Kristeva para entender cómo se va constituyendo en sus características principales: la intolerancia a la pérdida del objeto y el desfallecimiento del símbolo que le impide elaborar este duelo.

  6. Sobre Wittgenstein y la ética

    OpenAIRE

    García Soto, Luis

    2010-01-01

    El objeto de este trabajo es analizar y discutir la visión que de la ética da Wittgenstein en su “Conferencia sobre Ética” (1930). En nuestra opinión, la visión de la ética dada por el filósofo está más próxima de la religión o de la literatura que de otros sistemas normativos, como el derecho, la política e incluso la economía. De acuerdo con esto, intentamos ofrecer otra visión de la ética.

  7. Literatura infantil sobre problemas infantiles: la diabetes

    OpenAIRE

    Lázaro Fernández, Patricia

    2015-01-01

    Debido al creciente número de casos de diabetes infantil que se está dando en la sociedad actual, no es raro encontrarse en las aulas cada vez más casos de esta enfermedad. Por esta razón, he decidido analizar dos libros sobre esta temática, para hacer un acercamiento del material seleccionado a las aulas y poder desarrollar junto con los niños un aprendizaje colectivo y cooperativo. En este trabajo se expone la importancia de la literatura y la literatura infantil como una ...

  8. Comentarios sobre dibujo analítico

    OpenAIRE

    Mata Botella, Elena

    2004-01-01

    Cuaderno de apoyo a la docencia del DIBUJO DE ARQUITECTURA que pretende hacer reflexionar al alumno (de primero o segundo de carrera) sobre un tipo de dibujo que aquí se ha llamado “dibujo analítico”. Un dibujo que a través de operaciones gráficas y conceptuales como la esquematización y la selección de información, tiende a alejarse de la descripción del objeto arquitectónico para adentrarse en determinados aspectos o dimensiones que subyacen en el proyecto arquitectónico. Unas notas intr...

  9. Nuevas tecnologias: sobre computadores y brujas

    OpenAIRE

    Buenaventura, Juan Guillermo

    1987-01-01

    No soy ingeniero, ni experto en nuevas tecnologías. Cualquier comentario que haga no puede ser más que o bien el comentario de un ciudadano preocupado por su país o bien el acercamiento personal al tema, por parte de un comunicador interesado en los impactos y potencialidades, que tienen estas tecnologías en el ejercicio profesional y en nuestra cultura. A mi modo de ver la literatura conocida sobre las nuevas tecnologías oscila entre dos polos, dentro de los cuales se encuentran los diferent...

  10. Efecto del Diazepam sobre el desarrollo fetal

    OpenAIRE

    2001-01-01

    El diazepam se absorbe rápida y completamente después de la administración oral y atraviesa la barrera placentaria; su tasa de penetración en el tejido placentario es de 31,5% a las 4 horas, su vida media es prolongada y la existencia de metabolitos activos hace que su efecto sea acumulativo. Este trabajo se realizó en un modelo in vivo, usando 10 mg/Kg/día de diazepam intramuscular, en donde se estudió el efecto del diazepam sobre el desarrollo fetal, utilizando un modelo experimental en el ...

  11. Perspectivas sobre la comunicación

    OpenAIRE

    Naranjo Pereira, María Luisa

    2011-01-01

    Existen diversas teorías, enfoques y modelos de comunicación; de cada uno de ellos pueden rescatarse aspectos de gran valor para el logro de una comunicación eficaz. Este documento presenta una revisión de esos aspectos, para que se pueda comprender mejor y enriquecer uno de los procesos más importantes para el ser humano: el proceso de comunicación. Este es un ensayo en el cual se da a conocer la posición de la autora sobre el tema abordado. Se rescata el acento del enfoque humanista en la ...

  12. Apuntes Sobre el Cultivo del Cacao.

    Directory of Open Access Journals (Sweden)

    Ochoa Horacio Ochoa

    1940-12-01

    Full Text Available En el presente artículo se hablara del proceso de fermentación del cacao, pero antes de entrar a detallar este proceso, es conveniente dar algunas anotaciones sobre los sistemas de recolección o “cosecha” empleados en distintos lugares, pues ellos tienen sus diferencias y en ocasiones no se efectúan con todo el cuidado necesario tanto para el árbol como para el producto que irá a los depósitos de fermentación.

  13. Soportes apoyados sobre vigas pretensadas (EE. UU.

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1965-12-01

    Full Text Available This work has been awarded a prize by the Prestreesed Concrete Institute. It refers to a number of flyovers on the Arroyo Seco, of California. This river has been canalized, to help drainage in case of heavy rainfall. The canal runs through a highly populated zone, and a motor road and accessory ramps had to cross the canal. The resulting design involves three prestressed girders, lightly arched in a parabolic outline, resting on each river shore, running along the line of the bridge, over the canal. It was decided that the bridge piles should not rest on the river bed, in order not to reduce its flow capacity. The girders of a maximum length of 39 ms, are box shaped, and stiffened with thin diaphragms. The cylindrical pile, 1.50 m in diameter, is an integral part of the girder, and applies to it a concentrated load of about 4000 tons. The girders rest on reinforced concrete cubes, which in turn are supported by concrete slabs and piles driven into the soil.Esta obra ha sido premiada por el Prestressed Concrete Institute y se refiere a una serie de pasos superiores sobre el Arroyo Seco, en California, que se ha canalizado para servir de desagüe en el caso de avenidas torrenciales. El canal se halla en una zona de edificación densa y se trata del paso—sobre aquél—de una autopista y rampas de acceso. La solución adoptada consistió en tres vigas pretensadas, ligeramente arqueadas con perfil parabólico, apoyadas en las dos márgenes y situadas en correspondencia con los tres soportes, sobre el propio canal, ya que ninguno de aquéllos debía apoyarse en el lecho de este último al objeto de no disminuir su capacidad de desagüe. Las vigas—de unos 39 m de longitud la mayor—son del tipo cajón, rigidizadas con unos diafragmas de pequeño espesor. El soporte cilíndrico, de 1,50 m de diámetro, se solidariza con la viga y le transmite una notable carga concentrada, del orden de 4.000 toneladas. Los apoyos de estas vigas son simples dados

  14. Efectos del tabaquismo sobre el desarrollo prenatal

    OpenAIRE

    Carnero Cartujo, Sonia

    2014-01-01

    El tabaquismo es un problema de salud pública, causa enfermedad, incapacidad y muerte. El porcentaje de mujeres fumadoras mundialmente, alcanza el 22%. Si este porcentaje se mantiene durante el embarazo, debería tenerse en cuenta que la placenta humana es particularmente permeable a muchos de los compuestos en el humo del tabaco, y que existe suficiente evidencia científica de que los componentes del humo de un cigarrillo tienen efectos muy negativos sobre la vida intrauterina. La mayor parte...

  15. Phytotoxical effect of Lepidium draba L. extracts on the germination and growth of monocot (Zea mays L.) and dicot (Amaranthus retroflexus L.) seeds.

    Science.gov (United States)

    Kaya, Yusuf; Aksakal, Ozkan; Sunar, Serap; Erturk, Filiz Aygun; Bozari, Sedat; Agar, Guleray; Erez, Mehmet Emre; Battal, Peyami

    2015-03-01

    Laboratory experiments were performed to determine phytotoxic potentials of white top (Lepidium draba) methanol extracts (root, stem and leaf) on germination and early growth of corn (Zea mays) and redroot pigweed (Amaranthus retroflexus). Furthermore, the effects of different methanol extracts of L. draba on the phytohormone (indole-3-acetic acid (IAA), gibberellic acid (GA), abscisic acid (ABA) and zeatin) levels of corn and redroot pigweed were investigated. It was observed that all concentrations of methanol extracts of root, stem and leaf of L. draba inhibited germination, radicle and plumule elongation when compared with the respective controls. Besides this, the degree of inhibition was increased in concert with increasing concentrations of extracts used. On the other hand, phytohormone levels changed with the application of different extract concentrations. Comparing with the control, the GA levels significantly decreased while the ABA levels increased in all the application groups. Zeatin and IAA levels showed changes depending upon the applied extracts and concentrations.

  16. Characterizing pathways by which gravitropic effectors could move from the root cap to the root of primary roots of Zea mays

    Science.gov (United States)

    Moore, R.; McClelen, C. E.

    1989-01-01

    Plasmodesmata linking the root cap and root in primary roots Zea mays are restricted to approx. 400 protodermal cells bordering approx. 110000 microns2 of the calyptrogen of the root cap. This area is less than 10% of the cross-sectional area of the root-tip at the cap junction. Therefore, gravitropic effectors moving from the root cap to the root can move symplastically only through a relatively small area in the centre of the root. Decapped roots are non-responsive to gravity. However, decapped roots whose caps are replaced immediately after decapping are strongly graviresponsive. Thus, gravicurvature occurs only when the root cap contacts the root, and symplastic continuity between the cap and root is not required for gravicurvature. Completely removing mucilage from the root tip renders the root non-responsive to gravity. Taken together, these data suggest that gravitropic effectors move apoplastically through mucilage from the cap to the root.

  17. Enzymic synthesis of indole-3-acetyl-1-O-beta-d-glucose. I. Partial purification and characterization of the enzyme from Zea mays

    Science.gov (United States)

    Leznicki, A. J.; Bandurski, R. S.

    1988-01-01

    The first enzyme-catalyzed reaction leading from indole-3-acetic acid (IAA) to the myo-inositol esters of IAA is the synthesis of indole-3-acetyl-1-O-beta-D-glucose from uridine-5'-diphosphoglucose (UDPG) and IAA. The reaction is catalyzed by the enzyme, UDPG-indol-3-ylacetyl glucosyl transferase (IAA-glucose-synthase). This work reports methods for the assay of the enzyme and for the extraction and partial purification of the enzyme from kernels of Zea mays sweet corn. The enzyme has an apparent molecular weight of 46,500 an isoelectric point of 5.5, and its pH optimum lies between 7.3 and 7.6. The enzyme is stable to storage at zero degrees but loses activity during column chromatographic procedures which can be restored only fractionally by addition of column eluates. The data suggest either multiple unknown cofactors or conformational changes leading to activity loss.

  18. Effets du froid sur les stades précoces de développement du maïs (Zea mays L. (synthèse bibliographique

    Directory of Open Access Journals (Sweden)

    Riva-Roveda, L.

    2015-01-01

    Full Text Available Effects of cold temperatures on the early stages of maize (Zea mays L.. A review. Introduction. Maize is a crop of great economical importance. Despite its tropical origin and its high sensitivity to low temperatures, maize is now cultivated in a wide range of latitudes. To maintain competitive yields, many genetic and agricultural adaptations have been implemented. Literature. Plant responses to environmental stresses such as drought or cold have been extensively studied. This article reviews the progress and current knowledge regarding the effects of non-freezing cold temperatures on maize plants, from germination to floral transition. During the early stages of development, cold alters plant phenology and productivity, mainly because of its negative impact on photosynthesis. Plant growth is affected and secondary osmotic and oxidative stresses induce cell damage. Conclusion. A better understanding of the effects of cold will allow the development of new strategies for improving plant tolerance through the use of various physiological, genetic and molecular approaches.

  19. EFICIENCIA DEL AGUA DE RIEGO EN LA PRODUCCIÓN DE MAÍZ FORRAJERO (Zea mays L.) Y ALFALFA (Medicago sativa): IMPACTO SOCIAL Y ECONÓMICO

    OpenAIRE

    Aurelio Pedroza Sandoval; José Luis Ríos Flores; Myriam Torres Moreno; Jesús Enrique Cantú Brito; Cesar Piceno Sagarnaga; Luis Gerardo Yáñez Chávez

    2014-01-01

    El maíz y la alfalfa, son los dos principales cultivos forrajeros en la Cuenca Lechera de la Laguna de los estados de Coahuila y Durango, México, donde el recurso hídrico es el mayor factor limitante. El objetivo de este estudio fue hacer una evaluación de la eficiencia biológica, económica y social del uso de agua de riego en los cultivos de maíz forrajero (Zea mays L.) y alfalfa (Medicago sativa), mediante un análisis económico comparativo y de eficiencia de productividad. El maíz fue más e...

  20. Field Studies on the Relationship between Fusarium verticillioides and Maize (Zea mays L.: Effect of Biocontrol Agents on Fungal Infection and Toxin Content of Grains at Harvest

    Directory of Open Access Journals (Sweden)

    Paola Pereira

    2011-01-01

    Full Text Available Maize (Zea mays L. is a staple food for the majority of the world's population. Fusarium verticillioides (Sacc. Nirenberg (Teleomorph: Gibberella moniliformis Wineland; synonym: F. moniliformis is both a saprophyte and a parasite of maize and can also be found as an endophyte. The presence of this fungus in maize constitutes an imminent risk due to its ability to produce fumonisins, mycotoxins with proven carcinogenic effects. The present work investigated biocontrol activity of Bacillus amyloliquefaciens and Microbacterium oleovorans against F. verticillioides infection and fumonisin B1 production in field-grown maize during four consecutive growing seasons. Treatment with B. amyloliquefaciens consistently reduced F. verticillioides inoculum and fumonisin content of harvested grains. F. verticillioides count and fumonisin levels correlated negatively with rainfall regimes; however, none of these parameters showed significant correlation with yields. Treatment with these biocontrol agents may improve phytosanitary quality of the grains and reduce toxicological risk in the maize agroecosystem.

  1. PAM施用方式对土壤水热及玉米生长的影响%Effects of PAM with different application methods on soil moisture, soil temperature and growth of Zea mays

    Institute of Scientific and Technical Information of China (English)

    张蕊; 于健; 耿桂俊; 李晶晶; 白岗栓

    2013-01-01

    为了探寻PAM在玉米生产中的最佳施用方式,在河套灌区玉米播种时,以不施PAM为对照,研究PAM沟施、混施、撒施、穴施对土壤水分、土壤温度和玉米生长的影响.结果表明:1)在玉米生长的不同时期,PAM都可提高土壤水分,特别是在干旱的玉米抽雄吐丝期、灌浆期具有显著作用;2)PAM可延缓玉米幼苗期、三叶期的土壤温度回升,抑制玉米幼苗生长;3)从玉米拔节期开始,PAM可促进玉米生长,在玉米抽雄吐丝期、灌浆期效果最为显著;4)PAM沟施、混施、撒施、穴施的玉米产量分别较对照提高30.6%、39.3%、40.2%和31.7%,水分利用效率分别提高18.97%、25.43%、29.69%和20.46%,水分产出率分别提高31.36%、40.71%、42.15%和32.32%;5)在河套灌区,PAM撒施是玉米播种时相对适宜的施用方法.%In order to probe the best application methods of PAM in Zea mays production in Hetao Irrigation District,Inner Mongolia,PAM was applied with four methods of furrowing,mixing,broadcasting and holing,taken plots without PAM at Zea mays sowing as control.Effects of PAM on soil moisture,soil temperature and Zea mays growth status were studied at different growth stages of Zea mays.The results showed that:1) The application of PAM led to the increase of soil moisture during all growth stages of Zea mays,especially in drought stage of tasseling-silking and filling stages.2) The application of PAM hindered the rise of soil temperature in seedling and trefoil stages,and inhibited the growth of Zea mays seedling.3)The application of PAM promoted Zea mays growth from jointing stage,especially in tasseling-silking and filling stages.4)Compared with the control,Zea mays yields of furrowing,mixing,broadcasting and holing increased by 30.6%,39.3%,40.2% and 31.7% respectively,water use efficiency improved by 18.97%,25.43%,29.69% and 20.46% respectively,and water production rate improved by 31.36

  2. Utilization of metarhizium anisopliae and vegetable extract for control of the spodoptera frugiperda and helicoverpa zea (lepidoptera: noctuidae in the corn

    Directory of Open Access Journals (Sweden)

    Eduardo Barbosa Beserra

    2008-05-01

    Full Text Available The potential use of the vegetable extracts and Metarhizium anisopliae about the population and damage of the Spodoptera frugiperda and Helicoverpa zea in corn, it was evaluated when planted in two spacings. The experiment was installed in the culture of corn, in the city of Lagoa Seca/PB, in two areas of 500 m2, in the spacings 0,8 x 0,4 and 0,4 x 0,4 m, with two and one plant for hole. The basis was constituited of: 1 Water as witness; 2 Metarhizium anisopliae; 3 Extracts of Mormodica charantia; 4 Metarhizium anisopliae + extracts of M. charantia; 5 M. anisopliae + manipueira. The results showed some statistical difference between the two spacings, with a larger number of collected caterpillars, 5,84, and a larger damage to the plant, 3,24, in the spacing 0,4 x 0,4 m, in relation to the spacing 0,8 x 0,4 m, within as average of 4,13 caterpillars and danificated of 2,71. There was not any significant interaction between the spacings and the products used for the control of S. frugiperda. However, there was a significant difference among the treatments, with a smaller number of caterpillars, 4,17, and a smaller medium damage to the plant, 2,81, when was used, M. anisopliae + extract of M. charantia. Considering to the control of the plaque the percentage of damage ears of corn by H. zea, weight and length of the ear of corn in corn, there wasn’t neither significant difference with regard to the spacing, neither with regard to the used treatments.

  3. A novel Zea mays ssp. mexicana L. MYC-type ICE-like transcription factor gene ZmmICE1, enhances freezing tolerance in transgenic Arabidopsis thaliana.

    Science.gov (United States)

    Lu, Xiang; Yang, Lei; Yu, Mengyuan; Lai, Jianbin; Wang, Chao; McNeil, David; Zhou, Meixue; Yang, Chengwei

    2017-04-01

    The annual Zea mays ssp. mexicana L., a member of the teosinte group, is a close wild relative of maize and thus can be effectively used in maize improvement. In this study, an ICE-like gene, ZmmICE1, was isolated from a cDNA library of RNA-Seq from cold-treated seedling tissues of Zea mays ssp. mexicana L. The deduced protein of ZmmICE1 contains a highly conserved basic helix-loop-helix (bHLH) domain and C-terminal region of ICE-like proteins. The ZmmICE1 protein localizes to the nucleus and shows sumoylation when expressed in an Escherichia coli reconstitution system. In addition, yeast one hybrid assays indicated that ZmmICE1 has transactivation activities. Moreover, ectopic expression of ZmmICE1 in the Arabidopsis ice1-2 mutant increased freezing tolerance. The ZmmICE1 overexpressed plants showed lower electrolyte leakage (EL), reduced contents of malondialdehyde (MDA). The expression of downstream cold related genes of Arabidopsis C-repeat-binding factors (AtCBF1, AtCBF2 and AtCBF3), cold-responsive genes (AtCOR15A and AtCOR47), kinesin-1 member gene (AtKIN1) and responsive to desiccation gene (AtRD29A) was significantly induced when compared with wild type under low temperature treatment. Taken together, these results indicated that ZmmICE1 is the homolog of Arabidopsis inducer of CBF expression genes (AtICE1/2) and plays an important role in the regulation of freezing stress response.

  4. Isolation and Identification of Indigenous Plant Growth Promoting Rhizobacteria from Himalayan Region of Kashmir and their Effect on Improving Growth and Nutrient Contents of Maize (Zea Mays L.

    Directory of Open Access Journals (Sweden)

    Mahwish eZahid

    2015-03-01

    Full Text Available IIntroduction and exploitation of plant growth promoting rhizobacteria (PGPR in agro-ecosystems enhance plant-microbes interactions that may affect ecosystems sustainability, agricultural productivity and environmental quality. The present study was conducted to isolate and identify PGPRs associated with maize (Zea mays L. from twenty sites of Himalayan region of Hajira-Rawalakot, Azad Jammu and Kashmir (AJK, Pakistan. A total of one hundred isolates were isolated from these sites, out of which eight (HJR1, HJR2, HJR3, HJR4, HJR5, MR6, HJR7, HJR8 were selected in vitro for their plant growth promoting ability (PGPA including phosphorus solubilization, indole acetic acid (IAA production and N2 fixation. The 16S rRNA gene sequencing technique was used for molecular identity and authentication. Isolates were then further tested for their effects on growth and nutrient contents of maize (Zea mays L. under pouch and pot conditions. The 16S rRNA gene sequencing and phylogenetic analysis identified these isolates belong to Pseudomonas and Bacillus genera. The isolates promoted plant growth by solubilizing soil P which ranged between 19.2 and 35.6 µgmL−1. The isolates HJR1, HJR2, HJR3 and HJR5 showed positive activity in acetylene reduction assay showing their N2-fixation potential. All eight isolates showed the potential to produce IAA in the range of 0.9−5.39 µgmL−1 and promote plant growth. Results from a subsequent pot experiment indicated PGPRs distinctly increased maize shoot and root length, shoot and root dry weight, root surface area, leaf surface area, shoot and root N and P contents. Among the eight isolates, HR3 showed a marked P-solubilizing activity, plant growth-promoting attributes, and the potential to be developed as a biofertilizers for integrated nutrient management strategies

  5. Tributos sobre a folha ou sobre o faturamento? Efeitos quantitativos para o Brasil

    Directory of Open Access Journals (Sweden)

    Tiago V Cavalcanti

    2008-09-01

    Full Text Available Este artigo estuda os impactos alocativos e de bem-estar de uma reforma tributária que substitui os impostos sobre a folha de salários por outro que incide sobre a receita. Para isso, desenvolve-se um modelo neoclássico de crescimento econômico com impostos sobre a receita e sobre a folha de salários. As simulações com parâmetros da economia brasileira mostram que tal reforma tributária tem um efeito negativo no bem-estar, no estoque de capital de longo prazo e consequentemente no produto per capita de longo prazo. Contudo, o emprego aumenta.This paper studies the impacts of a tax reform which substitutes taxes on labor income by taxes on total revenue. In order to accomplish that, we construct and solve a general equilibrium neoclassical growth model with taxes on labor income and total revenue. The numerical simulations with Brazilian parameters show that such tax reforms would negatively affect welfare, the capital stock, and consequently per capita output. However, employment would increase. Such effects are quantitatively important.

  6. Effects of legume cover crop and sub-soiling on soil properties and Maize (Zea mays L) growth in semi arid area of Machakos district, Kenya = Efecto del cultivo de cobertua y el subsolado sobre las propiedades del suelo y crecimiento de maiz (Zea mays L.) en la region semi arida de Machakos, Kenia

    NARCIS (Netherlands)

    Karuma, A.; Gachene, C.K.K.; Gicheru, P.; Mwangombe, A.W.; Mwangi, H.W.; Clavel, D.; Verhagen, A.; Kaufmann, Von R.; Francis, J.; Ekaya, W.

    2011-01-01

    Low crop yields in the semi arid areas of Kenya have been attributed to, among other factors, low soil fertility, low farm inputs, labour constraints and inappropriate tillage practices that lead to pulverized soils. The aim of this study was to determine the effects of legume cover crops (LCC) on s

  7. INFLUENCE OF SUCCESSIVE CULTURES WITH ORGANIC FERTILIZATION ON PROTEIN LEVEL OF A CORN CULTIVAR (Zea mays L. INFLUÊNCIA DE SUCESSIVOS CULTIVOS COM ADUBAÇÃO ORGÂNICA SOBRE O TEOR DE PROTEÍNA DE UMA CULTIVAR DE MILHO (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Magda Beatriz A. Matteucci

    2007-09-01

    Full Text Available

    The corn grain is mainly used as energetic source, due to low levels of lisin and triptofane in protein. The corn protein level increases with nitrogenous fertilization. This study was carried out to verify the influence of successive cultures with organic fertilization on protein level of corn grain. The Demetria/EA/UFG cultivar is rustic and adapted to organic fertilization. It was observed significant effect every two successive cultures (Tukey 5% probability.

    KEY-WORDS: Organic fertilizer; protein; manure.

    O milho é utilizado principalmente como fonte de energia, tendo como característica proteínas pobres em usina e triptofano. Seu conteúdo protéico cresce com incrementos nas adubações nitrogenadas. A pesquisa teve como objetivo verificar a influência de sucessivos cultivos com adubação orgânica, na variação do teor de proteína nos grãos de milho, variedade Demétria/EA-UFG, uma cultivar rústica, própria para cultivos com adubação orgânica. Foi observado efeito significativo a cada dois cultivos sucessivos (teste de Tukey a 5 % de probabilidade.

    PALAVRAS-CHAVE: Adubação orgânica; proteína; esterco.

  8. Nuevas operaciones binarias sobre los conjuntos borrosos de tipo 2

    OpenAIRE

    Hernández Varela, Pablo Ramón; Cubillo Villanueva, Susana; Torres Blanc, Carmen

    2013-01-01

    Walker et al. ([19], [20]) definieron dos familias de operaciones binarias sobre M (conjunto de las funciones de [0,1] en [0,1]), y determinaron que, bajo ciertas condiciones, estas operaciones son tnormas (normas triangulares) o t-conormas sobre L (subconjunto de las funciones normales y convexas de M). En este trabajo se introducen dos operaciones binarias sobre M, diferentes a las dadas por Walker et al., y se estudian varias propiedades de las mismas, con el objeto de de...

  9. Consideraciones criminológicas sobre las bandas juveniles

    OpenAIRE

    Medina, Juanjo

    2010-01-01

    Este artículo ofrece una serie de reflexiones originales sobre la definición de las bandas juveniles y resume algunos de los debates claves en el campo de investigación sobre bandas. En particular, se presta especial atención a los estudios sobre la relación entre bandas y delincuencia, las teorías que explican la formación de las bandas y los factores que empujan a los jóvenes a vincularse a las mismas, los estudios sobre respuestas de política criminal a este fenómeno, ...

  10. Nivel de conocimientos del personal de salud sobre cuidados paliativos

    OpenAIRE

    2012-01-01

    Antecedentes: la medicina paliativa no figura en las prioridades de salud de México; en las instituciones existe un gran desconocimiento sobre las necesidades físicas, psicológicas, sociales y espirituales del paciente en estado terminal y sobre las de su familia; se reconoce que los profesionales de la salud carecen de conocimientos sobre cuidados paliativos. Objetivo: evaluar el nivel de conocimientos que sobre cuidados paliativos tiene el personal de salud de los tres niveles de atención m...

  11. Módulo educativo sobre emergencias escolares

    Directory of Open Access Journals (Sweden)

    Ana María Fajardo-Maldonado

    2009-01-01

    Full Text Available Con el fin de conocer el comportamiento ante emergencias escolares de niñas y adolescentes, se realizó una investigación descriptiva sobre el impacto de un proceso educativo de un programa de salud al colegio. El estudio se adelantó entre el 2007 y el 2008, en la localidad de Suba, en Bogotá, con un grupo de 120 estudiantes, de 6 a 18 años, de estratos cero, uno y dos. Mediante una metodología lúdica, pedagógica y de experiencias se evaluaron los conocimientos impartidos a esta población, en la que se observaron cambios en los estilos de vida y hábitos individuales y grupales. El 95% de las niñas validaron los conocimientos en salud sobre el manejo de emergencias escolares, el 100% de la población participó en la construcción del plan y trabajó en las prácticas, lo que crea conciencia acerca de la importancia del programa de salud escolar con el desarrollo de este tipo de planes.

  12. Debate sobre estudios postcoloniales y subalternos

    Directory of Open Access Journals (Sweden)

    David Morris

    2001-01-01

    Full Text Available A partir de los comentarios a la reseña elaborada por Ian S. Mclean sobre el libro: Cuerpos incas y el cuerpo de Cristo. El Corpus Christi en Cuzco colonial, Perú, escrito por Carolyn Dean, surge un debate sobre los Estudios Postcoloniales y Subalternos, que se desarrolló entre el 12 de agosto y el 3 de septiembre de 2001, a través de la lista de correo electrónico de H-Latam, grupo de discusión dedicado a la historia latinoamericana. En él participaron destacados especialistas en el tema, quienes analizaron, entre otras cuestiones, el uso de la jerga y las formas de escritura, la novedad de sus planteamientos, sus influencias filosóficas y epistemológicas, su pretensión de captar el punto de vista de los vencidos y subordinados, la pertinencia de unas ideas originalmente desarrolladas para el estudio del colonialismo inglés y luego aplicadas al colonialismo español en América Latina.

  13. sobre la representatividad democrática

    Directory of Open Access Journals (Sweden)

    Adriana Gallo

    2008-01-01

    Full Text Available En este trabajo se evalúan los efectos que reviste la aplicación de tres instrumentos sugeridos o implementados, a partir de las últimas reformas político-institucionales –primarias abiertas, sistema de doble vuelta, y reelección inmediata– sobre la representatividad partidaria en Argentina, Chile y Uruguay. La relevancia del análisis de estos mecanismos en conjunto se debe a que, por un lado, cada uno concierne a una de las tres instancias del proceso electivo trifásico –selección, elección y reelección, respectivamente–; y, por otro, los tres comparten objetivos similares que sintéticamente son: dotar de más herramientas de discernimiento político a los ciudadanos, proveer de mejores condiciones democráticas a los partidos e incrementar la legitimidad electoral del presidente. Luego del análisis comparativo de tres países con trazos diferenciados, se concluye que los costos ocultos que pueden suscitarse con cada mecanismo analizado superan a los beneficios potenciales de alguno de ellos, operando negativamente sobre la representatividad democrática.

  14. Impacto de la senescencia foliar sobre la producción de fotoasimilados y el rendimiento de maíz (Zea mays L.) bajo condiciones de estrés abiótico

    OpenAIRE

    Antonietta, Mariana A.

    2013-01-01

    El objetivo general de esta tesis fue estudiar si la demora en la senescencia foliar (carácter stay-green, SG) en híbridos de maíz confiere tolerancia del rendimiento al estrés abiótico. Se realizaron ensayos a campo utilizando híbridos contrastantes en la senescencia foliar. Se registró la evolución de la senescencia, la producción neta de fotoasimilados, el rendimiento y sus componentes. Bajo sequía en post-floración, los genotipos SG presentaron mayor producción de fotoasimilados y esto se...

  15. ANÁLISIS ECOFISIOLÓGICO DEL CULTIVO ASOCIADO MAÍZ (Zea mays L. - FRÍJOL VOLUBLE (Phaselus vulgaris L. ECOPHYSIOLOGICAL ANALYSIS OF CORN (Zea mays L. - CLIMBIMG COMMON BEAN (Phaselus vulgaris L. INTERCROPPING

    Directory of Open Access Journals (Sweden)

    León Darío Vélez Vargas

    2007-12-01

    Full Text Available El objetivo es analizar el estado del conocimiento del cultivo asociado maíz-fríjol voluble trepador (MxFv, desde una perspectiva ecofisiológica. Se parte de la revisión de las variables evaluadas en las investigaciones consultadas y su clasificación en variables descriptivas, explicativas y condicionantes. Esta clasificación permitió establecer el carácter predominantemente descriptivo de la mayoría de las investigaciones con respecto a los efectos de la competencia por recursos del suelo y luz sobre las especies asociadas, principalmente en el rendimiento. Solo unas pocas investigaciones abordan el estudio de aspectos morfológicos, de componentes del rendimiento y dinámica del crecimiento y desarrollo de ambas especies, que pueden contribuir a identificar y explicar las causas de los efectos del asocio sobre el comportamiento de ambas especies, como en el caso del rendimiento. Las investigaciones se han concentrado en variables condicionantes como genotipos y densidad de población. En la asociación, el fríjol es la especie más afectada; sin embargo, su alta plasticidad morfofiosiológica posibilita las ventajas de la asociación frente a los unicultivos de maíz y fríjol. La comprensión del funcionamiento de la asociación permitirá avanzar en el mejoramiento de la producción de maíz y fríjol en asocio y de la relaciones de competencia en los agroecosistemas.This paper reviews the state of knowledge on maize - climbing bean intercropping from an ecophysiological perspective. Starting from the revision of evaluated variables in the consulted investigations and classifing them within three categories: descriptive, explanative and conditional variables. This classification provides elements to argue that researches have been more descriptive than explanative. Many studies describe both association effects and conditionals variables, such as genotypes and population densities, while few studies focus on the mechanisms that

  16. Control Sitophilus zeamais (Coleoptera: Curculionidae in Maize (Zea mays L. treated with diatomaceous eart Coltrol de Sitophilus zeamais (Coleoptera: Curculionidae en maíz (Zea mays L. tratados con tierra de diatomeas Controle de Sitophilus zeamais (Coleoptera: Curculionidae em milho (Zea mays L. tratado com terra de diatomácea

    Directory of Open Access Journals (Sweden)

    Juliana Neitzke

    2010-04-01

    Full Text Available

    Maize (Zea mays L. is one of the most important cereals grown worldwide. As the product is sold fresh, the major concern is to maintain the quality of the grain, but its storage is difficult due to wide range of pests that can attack, reducing the quality. The objective of this study was to evaluate the effect of diatomaceous earth in the mortality of maize weevil Sitophilus zeamais in maize grains stored in different dosages and check the exposure time of each treatment. The experimental design was completely randomized with six treatments and five replications. The treatments consisted of increasing doses of diatomaceus eart (DE, in the proportion of zero, 50, 100, 150, 200, 250 g of DE t-1, all packed in plastic cups of 250 mL. In each plastic cup it was released 20 insects of S. zeamais and they were closed with fabric nylon fine mesh for aeration. The evaluation of insect mortality were performed at 3, 6 and 9 days after infestation (DAI, by counting the living and dead insects in the trays and the possible re-infestation. Treatment with diatomaceous earth in maize (Zea mays at a dosage of 250 g t-1 provided better control of S. zeamais.

    O milho (Zea mays L. é um dos cereais mais importantes cultivados no mundo todo. Como o produto é vendido “in natura”, a grande preocupação é manter a qualidade do grão, mas o seu armazenamento é dificultado devido à grande gama de pragas que podem atacar, diminuindo a qualidade. O objetivo deste trabalho foi avaliar o efeito da terra de diatomácea na mortalidade do gorgulho de milho Sitophilus zeamais em grãos armazenados de milho em diferentes dosagens e verificar o tempo de exposição de cada tratamento. O delineamento experimental foi inteiramente casualizado, com seis tratamentos e cinco repetições. Os tratamentos consistiram em doses crescentes de pó inerte terra de diatom

  17. Hábitos de consumo sobre la cerveza

    OpenAIRE

    Velasco Matilla, Débora

    2015-01-01

    Estudio de los hábitos de consumo de cerveza en un pueblo determinado situado en la provincia de Segovia, Cantalejo. Contiene un resumen sobre la historia de la cerveza y su tipología y un estudio de mercado sobre la cerveza partiendo de una encuesta. Grado en Comercio

  18. Violência sobre Crianças

    OpenAIRE

    Sacadura, Catarina Brito; Aragão, Maria José

    2014-01-01

    Trata-se de um estudo de revisão sobre a violência exercida sobre crianças, os agentes da violência, os sujeitos da violência, os factores de risco, as consequências na idade adulta e a recidividade de violência sexual.

  19. Generalizaciones y creencias sobre el autismo: estudio descriptivo

    OpenAIRE

    Rodríguez Fernández, Patricia

    2015-01-01

    La autora propone una investigación sobre las creencias más generalizadas en diferentes aspectos del autismo: etiología, características, escolarización y pronóstico en diferentes grupos de edades con distinta familiaridad sobre este trastorno y con distinto nivel educativo general.

  20. Neruda e Drummond: um olhar sobre Stalingrado

    Directory of Open Access Journals (Sweden)

    Moacir Lopes de Camargos

    2015-07-01

    Full Text Available Este artigo tem por objetivo promover uma aproximação entre dois expoentes da lírica latino-americana do século XX, a saber: Pablo Neruda e Carlos Drummond de Andrade, a partir da análise dos poemas Canto a Stalingrado (1942 e Carta a Stalingrado (1943. Apresentaremos a visão histórica desses poetas sobre a Batalha de Stalingrado, considerada um dos principais eventos da Segunda Guerra Mundial. Ademais, será abordada a questão do engajamento político, que envolve a produção poética dos referidos autores.