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Symptom severity and viral protein or RNA accumulation in lettuce affected by big-vein disease
Araya,Carolina; Pe?a,Elizabeth; Salazar,Erika; Román,Lisset; Medina,Claudia; Mora,Roxana; Aljaro,Agustín; Rosales,Inés-Marlene;
Chilean journal of agricultural research , 2011, DOI: 10.4067/S0718-58392011000100008
Abstract: big-vein disease (bvd) is a widespread and economically damaging disease in lettuce (lactuca sativa l.). typical symptoms are chlorotic clearing around leaf veins, leaf deformations, and impaired head development. in this research, we studied the relationship between symptom intensity and protein and viral rna accumulation in infected plants. naturally infected lettuce plants, from the field or greenhouse, were classified according to their symptomatology: mild, moderate, severe, and symptomless. coat protein accumulation was evaluated by a double antibody sandwich/enzyme-linked immunosorbent assay (das-elisa), and rna levels were studied by semi-quantitative reverse transcription polymerase chain reaction (rt-pcr) and quantitative rt-pcr. virus coat protein accumulation did not differ for the two viruses associated with this disease among lettuce plants showing different symptom severity. similarly, abundance of mirafiori lettuce big-vein virus (mlbvv)-rna3 or lettuce big-vein associated virus (lbvav)-rna-2 were not different (p > 0.05) for diverse big vein disease severity rating scales. this suggests that symptom severity expressed by big-vein diseased lettuce plants did not necessarily reflect the accumulation of viruses associated with this disease in the host. therefore, lettuce plants showing mild symptoms of bvd do not necessarily present lower virus levels than plants showing more severe symptomatology.
Root Morphology, Plant Growth, Nitrate Accumulation and Nitrogen Metabolism of Temperate Lettuce Grown in the Tropics with Elevated Root-Zone CO2 at Different Root-Zone Temperatures  [PDF]
Jie He, Lin Qin, Sing Kong Lee
American Journal of Plant Sciences (AJPS) , 2016, DOI: 10.4236/ajps.2016.714169
Abstract: This paper investigated the effects of root-zone (RZ) CO2 concentration ([CO2]) on root morphology and growth, nitrate (NO3-) uptake and assimilation of lettuce plants at different root-zone temperatures (RZT). Elevated RZ [CO2] stimulated root development, root and shoot growth compared to ambient RZ [CO2]. The greatest increase in root growth was observed in plants grown under elevated RZ [CO2] of 50,000 ppm. However, RZ [CO2] of 10,000 ppm was sufficient to achieve the maximal leaf area and shoot productivity. Lettuce plants exhibited faster shoot and root growth at 20°C-RZT than at ambient (A)-RZT. However, under elevated RZ [CO2], the magnitude of increased growth was greater at A-RZT than at 20°C-RZT. Compared to RZ [CO2] of 360 ppm, elevated RZ [CO2] of 10,000
Nitrogen fertilization on intercropping of lettuce and rocket
Barros Júnior, Aurélio P;Cecílio Filho, Arthur B;Rezende, Bráulio Luciano A;P?rto, Diego RQ;Prado, Renato de M;
Horticultura Brasileira , 2011, DOI: 10.1590/S0102-05362011000300024
Abstract: the work was carried out at unesp, jaboticabal, s?o paulo state, brazil, from september to december 2006, to evaluate the effect of nitrogen fertilization on intercropping of lettuce and rocket. the experiment was conducted in a randomized complete block design, with four replications, treatments being arranged in a 4 x 4 + 2 factorial design. the treatments were the result of a combination of four n rates for lettuce (0, 65, 130 and 195 kg ha-1) and four n rates for rocket (0, 65, 130 and 195 kg ha-1), plus two additional treatments, which corresponded to lettuce and rocket under single cropping. veronica (lettuce) and folha larga (rocket) were the cultivars used. an increase in the n rate for both cultures, under intercropping system, caused fresh matter gains and higher yields for lettuce and rocket, maximizing the land equivalent ratio (1.84) at 127 kg ha-1 of n for lettuce and 195 kg ha-1 of n for rocket.
ACCUMULATION OF NITROGEN COMPOUNDS AND NITRATE REDUCTASE ACTIVITY IN LETTUCE CULTIVATED IN DIFFERENT CROP SYSTEMS ACúMULO DE COMPOSTOS NITROGENADOS E ATIVIDADE DA REDUTASE DO NITRATO EM ALFACE PRODUZIDA EM DIFERENTES SISTEMAS DE CULTIVO
Juliana Domingues Lima,Wilson da Silva Moraes,Sílvia Helena Gorla Modenese da Silva,Fernanda Nunes Ibrahim
Pesquisa Agropecuária Tropical , 2008, DOI: 10.5216/pat.v38i3.3325
Abstract: Nitrate content determination is important for food quality evaluation, therefore when ingested nitrate is reduced the nitrite, which can generate harmful compounds to the human organism. Ahead of this, the present work had as objective to study the transport and accumulation of nitrogen compounds and the nitrate reductase activity in lettuce cultivar 'Vera' produced in Registro (SP) in different cropping systems. Were collected samples of the xylem sap, aerial part and root for quantification of nitrogen compounds and of the reductase activity in vivo. The nitrate concentration in the xylem sap, the nitrate and amino acids contents, as well as the nitrate reductase activity, demonstrated more intense transport, accumulation and assimilation in plants cultivated in in hydroponic solution, followed of the conventional system and finally, of the organic. The stem of the plant in the three systems of culture presented high capacity of accumulation and assimilation the nitrogen compounds. The nitrate reductase activity in leaves was superior of the root. The content nitrate, independent of the culture system, varied of 24.32 the 800.06 mg kg-1 of FW in the different parts of the plant. However, it did not exceed the maximum limits recommended by literature. KEY-WORDS: Vegetables; quality; nitrite; metabolism of nitrogen. O teor de nitrato é um importante índice da qualidade dos alimentos, pois quando ingerido nitrato é reduzido a nitrito, o qual pode gerar compostos prejudiciais ao organismo humano. Diante disso, o presente trabalho teve como objetivo estudar o transporte e acúmulo de compostos nitrogenados e a atividade da enzima redutase do nitrato em alface cultivar 'Vera' produzida em Registro (SP) em diferentes sistemas de cultivo. Foram coletadas amostras da seiva do xilema, da parte aérea e da raiz das plantas para quantifica o de compostos nitrogenados e atividade da redutase do nitrato in vivo. A concentra o de nitrato na seiva xilema, os teores de nitrato e aminoácidos, bem como a atividade da redutase do n
Effects of long-term fertilization modes on spatio-temporal distribution and accumulation of soil nitrate nitrogen in solar greenhouse
长期不同施肥模式对日光温室土壤硝态氮时空分布及累积的影响

YANG He-F,FAN Ju-Fang,LIANG Li-N,YANG Yu-Bao,NIU Ling-An,LI Ji,
杨合法
,范聚芳,梁丽娜,杨玉宝,牛灵安,李季

中国生态农业学报 , 2011,
Abstract: Continuous localization experiment was conducted for seven years to study the spatio-temporal distribution and accumulation of soil nitrate nitrogen in solar greenhouse. The study showed that nitrate nitrogen content increased through soil profile with increasing planting time. The order of annual increment in soil nitrate nitrogen in relation to fertilization mode was as follows: conventional fertilization > low-input fertilization > organic fertilization. The main nitrate nitrogen distribution soil layer was 0~40 cm. Nitrate nitrogen content in the 0~60 cm soil layer was low at the early stage, high at the middle stage and low at the late stage of crop growth. Compared with the upper soil layers, nitrate nitrogen content in soil layers below 100 cm was increased. Average nitrate nitrogen accumulation in the 0~200 cm soil layer was 33.8% and 45.9% less in organic fertilization mode than in low-input and conventional fertilization modes. It was also 18.3% less in low-input fertilization mode than in conventional fertilization mode. Nitrate nitrogen leaching tendency to soil layers below 200 cm was observed in all three fertilization modes. Compared with conventional fertilization mode, organic fertilization mode obviously reduced nitrate nitrogen content in the soil profiles and retarded downward movement of nitrogen. However, improper application of organic fertilizer induced soil nitrate nitrogen leaching which led to environmental pollution.
Determination of nitrate in lettuce by ion chromatography after microwave water extraction
Novaes, Humberto Brevilato;Vaitsman, Delmo Santiago;Dutra, Paulo Bechara;Pérez, Daniel Vidal;
Química Nova , 2009, DOI: 10.1590/S0100-40422009000600049
Abstract: lettuce is worldwide known as the most important vegetable. in this context, most farmers are searching new techniques for best quality products including hydropony. however, nitrate is of great concern, since it has a negative impact on human metabolism. the main objective of the present work was to evaluate the nitrate content of lettuce produced by conventional and hydroponic systems. the determination was conducted by ion chromatography and a new method of extraction was tested using microwave oven digestion. the results indicated that nitrate level produced in the conventional system was lower than in the hydroponic system.
Symptom severity and viral protein or RNA accumulation in lettuce affected by big-vein disease Severidad de síntomas y acumulación de proteínas o ARN virales en lechugas afectadas por la enfermedad de las venas grandes  [cached]
Carolina Araya,Elizabeth Pe?a,Erika Salazar,Lisset Román
Chilean Journal of Agricultural Research , 2011,
Abstract: Big-vein disease (BVD) is a widespread and economically damaging disease in lettuce (Lactuca sativa L.). Typical symptoms are chlorotic clearing around leaf veins, leaf deformations, and impaired head development. In this research, we studied the relationship between symptom intensity and protein and viral RNA accumulation in infected plants. Naturally infected lettuce plants, from the field or greenhouse, were classified according to their symptomatology: mild, moderate, severe, and symptomless. Coat protein accumulation was evaluated by a double antibody sandwich/enzyme-linked immunosorbent assay (DAS-ELISA), and RNA levels were studied by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and quantitative RT-PCR. Virus coat protein accumulation did not differ for the two viruses associated with this disease among lettuce plants showing different symptom severity. Similarly, abundance of Mirafiori lettuce big-vein virus (MLBVV)-RNA3 or Lettuce big-vein associated virus (LBVaV)-RNA-2 were not different (P > 0.05) for diverse big vein disease severity rating scales. This suggests that symptom severity expressed by big-vein diseased lettuce plants did not necessarily reflect the accumulation of viruses associated with this disease in the host. Therefore, lettuce plants showing mild symptoms of BVD do not necessarily present lower virus levels than plants showing more severe symptomatology. La enfermedad de las venas grandes de la lechuga (Lactuca sativa L.) es de origen viral, está ampliamente distribuida en el mundo, y provoca graves da os económicos en este cultivo. Los síntomas típicos de la enfermedad son clorosis alrededor de las venas, deformación de hojas y ausencia de formación de cabezas. En este trabajo se estudió la relación entre la intensidad de síntomas y la acumulación de proteínas y ARNs de origen viral en plantas afectadas por esta enfermedad. Lechugas infectadas naturalmente, provenientes de campo y de invernadero fueron clasificadas con sintomatología leve, intermedia, severa, y asintomáticas. La acumulación de proteínas de cubiertas virales fue evaluada utilizando DAS-ELISA (sandwich con doble anticuerpo-ensayo inmunoabsorbente ligado a enzima), y los niveles de ARN viral se estudiaron por medio de transcripción reversa-reacción en cadena de la polimerasa (RT-PCR) semicuantitativa y RT-PCR cuantitativa. No hubo diferencia en la acumulación de proteínas virales para los dos virus asociados a esta enfermedad, al comparar plantas de lechugas con distintos niveles de severidad de síntomas. De forma similar, cuando
Cadmium availability and accumulation by lettuce and rice
Pereira, Bruno Fernando Faria;Rozane, Danilo Eduardo;Araújo, Suzana Romeiro;Barth, Gabriel;Queiroz, Rafaela Josemara Barbosa;Nogueira, Thiago Assis Rodrigues;Moraes, Milton Ferreira;Cabral, Cleusa Pereira;Boaretto, Antonio Enedi;Malavolta, Eurípedes;
Revista Brasileira de Ciência do Solo , 2011, DOI: 10.1590/S0100-06832011000200033
Abstract: among the toxic elements, cd has received considerable attention in view of its association with a number of human health problems. the objectives of this study were to evaluate the cd availability and accumulation in soil, transfer rate and toxicity in lettuce and rice plants grown in a cd-contaminated typic hapludox. two simultaneous greenhouse experiments with lettuce and rice test plants were conducted in a randomized complete block design with four replications. the treatments consisted of four cd rates (cdcl2), 0.0; 1.3; 3.0 and 6.0 mg kg-1, based on the guidelines recommended by the environmental agency of the state of s?o paulo, brazil (cetesb). higher cd rates increased extractable cd (using mehlich-3, mehlich-1 and dtpa chemical extractants) and decreased lettuce and rice dry matter yields. however, no visual toxicity symptoms were observed in plants. mehlich-1, mehlich-3 and dtpa extractants were effective in predicting soil cd availability as well as the cd concentration and accumulation in plant parts. cadmium concentration in rice remained below the threshold for human consumption established by brazilian legislation. on the other hand, lettuce cd concentration in edible parts exceeded the acceptable limit.
Nutrient absorption and response of lettuce to phosphorus fertilization
Cristiaini Kano,Antonio Ismael Inácio Cardoso,Roberto Lyra Villas Boas
Biotemas , 2012,
Abstract: The objective of this study was to evaluate the response of lettuce (cultivar Ver nica) to different levels of phosphorus fertilization. The experiment was conducted from 25/09/2003 (sowing) to 03/12/2003 (harvesting) at the Fazenda Experimental S o Manuel, UNESP/FCA, Botucatu/SP, under protective structures. The experiment was conducted in a randomized block design, with five treatments (0, 200, 400, 600 and 800kg.ha-1 of P2O5, in the form of triple superphosphate) and five replications. Plants were grown in 13L plastic pots containing Latossolo Vermelho Distrófico Típico. A quadratic response was observed for the fresh mass of the plant shoots and leaf area, with maximum equivalent levels of 733 and 756kg.ha-1 of P2O5, respectively, as well as for potassium, calcium, magnesium, sulfur, boron, copper, iron, manganese and zinc accumulation. Linear increases were observed with the treatments of P2O5 for dry mass of the shoots, leaf number, plant height and nitrogen and phosphorus accumulation.
Nitrate Content on Summer Lettuce Production Using Fish Culture Water
E. Rico-Garcia,V.E. Casanova-Villareal,A. Mercado-Luna,G.M. Soto-Zarazua
Trends in Agricultural Economics , 2009,
Abstract: The aim of this study was to investigate the nitrate concentration on lettuce (Lactuca sativa cv. Px06516006) grown in fish culture water. This study was carried out in Queretaro State, Mexico. Lettuce cultivars were grown in a floating system inside a plastic greenhouse. The cultivation of lettuce was divided into 10 beds; four beds were used as a control group, with a standard nutrient solution and the other six beds were used as treatment group, fish culture water with the addition of missing nutrients. A density of 30 plants m-2 was used. Two trial periods were tested in the summer of 2008, 29 days from April 11 to May 9 for the first experiment and 37 days from May 22 to June 27 for the second experiment. The system was assessed on basis of leaves nitrate content, total fresh weight and total dry weight. In both trials the final nitrate content of leaves was less than 2400 mg kg-1. No significant differences (p<0.05) were found for fresh and dry weights among treatments. Based on these results it is shown that fish culture water is suitable for low nitrate content lettuce production with no detriment to plant quality neither yields during summer.
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