Effects of plant density and the number of emitters on plant growth and nitrate concentration in spinach cultivated in substrate

The effects of plant density and the number of emitters per Styrofoam box on plant growth and nitrate (NO3-) concentration were evaluated in spinach (Spinacia oleracea L. cv. Tapir). Spinach seedlings were transplanted at 45 days after emergence into Styrofoam boxes filled with the substrate and were grown during winter in an unheated greenhouse with no supplemental lighting. The experiment was carried out with four treatments, including two plant densities (160 and 280 plants/m2) and two number of emitters per Styrofoam box (4 and 8 emitters). Each planting box was irrigated daily and fertigated with a complete nutrient solution. Shoot dry weight was not affected by plant density. However, yield increased with plant density and emitter number. Leaf-blade NO3- concentration was not affected by the interaction between plant density and number of emitters, but petioles NO3- concentration was greater in treatment with 160 plants/m2 and 8 emitters. Although leaf-blade NO3- concentration was not affected by plant density, it decreased with the number of emitters. On the other hand, petiole NO3- concentration was not affected by plant density or number of emitters. Leaf-blade NO3- concentration ranged from 3.2 to 4.1 mg/g fresh weight, occurring the highest value in the treatment with 280 plants/m2 and 4 emitters. Petiole NO3- concentration ranged from 3.5 to 5.3 mg/g fresh weight, values that were higher than allowed by EU regulation.

Nitrate and potassium concentration in fertigated soil cultivated with wine vines.

In the semiarid region of Brazil the use of irrigation systems for applying fertilizers in horticulture is the primary means for incorporating nutrients in the soil. However, this technique still requires its use in wine vines to be assessed. In view of this, this study aimed to assess nitrate and potassium concentrations in soil fertigated with nitrogen and potassium fertilizers in 3 wine grape growing cycles. A field experiment was conducted with ?Syrah? wine grapes, in Petrolina, Pernambuco, Brazil; it assessed five nitrogen doses (0, 15, 30, 60 and 120 kg ha-1) and five K2O doses (0, 15, 30, 60 and 120 kg ha-1) applied by drip irrigation system with two emitters per plant, with a flow rate of 4 L h-1. The experimental design used was the factorial split-plot, making up 13 combinations arranged in 4 randomized blocks. Soil solution samples were collected weekly with the aid of porous cup extractors for all treatments and at depths of 0.4 and 0.6 m by determining nitrate and potassium concentrations and electrical conductivity. Increased levels of both nutrients in the irrigation water increased the availability of nitrate and potassium in the soil solution. The highest nitrate and potassium concentrations were found in the second growing cycle at both depths studied.

Microbial activities in soils cultivated with transgenic maize expressing Bacillus thuringiensis Cry1 Ab and Cry1 F genes.

A área brasileira plantada com milho geneticamente modificado (GM) expressando genes Cry derivados da bactéria do solo Bacillus thuringiensis (Bt) aumentou de 4,9% (5,0 milhões de hectares) da área total plantada em 2009 para 81,4% (15,83 milhões de hectares) em 2014. No entanto, estudos sobre os efeitos da tecnologia Bt-milho sobre microrganismos não alvo em solos tropicais são incipientes. Dessa forma, foi realizado experimento de campo para avaliar a atividade fisiológica das comunidades bacterianas associadas com genótipos de milho Bt plantados em Latossolo Vermelho Escuro do Cerrado e solos hidromórficos da planície com inundações localizadas. Um híbrido não transgênico (30F35) e seus homólogos transgênicos 30F35Y (Cry1Ab) e 30F35H (Cry1F) foram plantados com delineamento de blocos casualizados com quatro repetições. Solos rizosféricos e não rizosféricos coletados de plantas no estádio de florescimento foram submetidos aos ensaios de diversidade metabólica com Biolog e atividades enzimáticas de urease, arginase, fosfatase ácida e fosfatase alcalina. Solos rizosféricos apresentaram maior atividade microbiana e não foram detectadas diferenças significativas entre os genótipos em todos os parâmetros bioquímicos e de solo avaliados. Os resultados sugerem que o milho Bt não afeta negativamente a comunidade microbiana dos solos tropicais.

Effect of nitrogen fertilization on soil microbial biomass in an Oxisol cultivated with irrigated barley in the Brazilian Cerrado.

Abstract:The aim of this study was to evaluate the effect of different nitrogen doses and five period of sample collection, on soil microbial biomass - nitrogen (SMB-N), total nitrogen (total N) and percentual ratio of the microbial biomass and total N (SMB-N/total N) in a Oxisol cultivated with barley (Hordeum vulgare L.). The experiment was installed in June, 2005, in an area located at Embrapa Cerrados, Federal District. The experimental design was a randomized block, with three replicates. The plots received doses of nitrogen: 20 - 40 - 80 kg ha-1 N and a control without it and the subplots were period of soil sample. Three applications of N were realized: 10 kg ha-1 on the 5th day (06/14) after sowing; the rest of N was parceled in two applications with fertigation, on tillage, on the 27th (07/08) DAP, e no 43rd (07/22) DAP. Soil samples layer (0 - 10 cm deep) were collected for (SMB-N) determination and total N in six periods: 02 days before of the first fertigation; 02 days after of the first fertigation; 04 days before of the last fertigation and 04 days after of the last fertigation; on flowering stage and after harvesting. There was effect of the doses of N and the period of soil collection on the SMB-N, total N and in the ratio SMB-N/total N. The average values of total N revealed steadier in short-term (cycle of the culture) and this was not a good parameter to evaluate the behavior and N transformations in the soil-plant system. Resumen: El objetivo de este estudio fue evaluar el efecto de diferentes dosis de nitrógeno y cinco período de muestreo en la biomasa microbiana del complejo suelo - nitrogeno (BMS-N), nitrógeno total (N total) y la relación porcentual de la biomasa microbiana y N total (BMS-N/N total) en un Oxisol cultivado con cebada (Hordeum vulgare L.). El estudio se inició en junio de 2005 en la estación experimental de la Empresa de Pesquisa Agropecuaria (Embrapa-Cerrados), Distrito Federal, Brazil. El experimento se dispuso en bloques al azar con tres repeticiones. Las parcelas recibieron dosis de nitrógeno: 20 - 40 - 80 kg/ha de N más un control sin N, y las subparcelas fueron el periodo de muestro. Las aplicaciones de N se realizaron de la forma siguiente: cinco días después de la siembra (dds) se aplicaron 10 kg/ha y el resto de la dosis se aplicó con fertirrigación en dos dosis 27 y 43 dds. Las muestras de suelo (0-10 cm de profundidad) para determinar BMS-N y N total fueron tomadas, 2 días antes e igual número de días después de la primera fertirrigación y 4 días antes y después de la última, en floración y después de la cosecha. No se encontró efecto de las dosis de N y el período de muestreo en el BMS-N, N total y en la relación BMS-N/N total. Los valores medios de N total fueron más estable en el corto plazo (ciclo de la cultivo) lo que indica que éste no es un buen parámetro para evaluar la dinámica del N y sus transformaciones en el sistema suelo-planta.

Mini tomato cultivars for the Sub-Mid São Francisco Valley, Brazil.

In this context, the objective of this work was to evaluate the performance of mini tomato cultivars of determinate growth habit, in two crop seasons in the conditions of the Sub-Mid São Francisco Valley, Brazil.

Secretome analysis of the mycoparasitic fungus Trichoderma harzianum ALL 42 cultivated in different media supplemented with Fusarium solani cell wall or glucose.

2016

Primeiro relato de Tomato chlorotic spot virus em alface no estado do Pará.

A alface é uma hortaliça folhosa de grande importância econômica e social no Brasil, pois bastante cultivada por pequenos produtores e em hortas familiares. Isto ocorre principalmente pela facilidade que a cultura apresenta em se adaptar às mais diferentes condições. As doenças causadas por vírus são as principais responsáveis pelas perdas na produção na cultura, entre elas destacam-se as causadas por vírus do gênero Tospovirus. Durante visitas realizadas a áreas produtoras de hortaliças localizadas na região metropolitana de Belém-Pará, foi observada a alta incidência de plantas com sintomas de viroses. Assim, o trabalho teve como objetivo identificar o agente causal do vira cabeça da alface, por meio de RT-PCR e sequenciamento do ácido nucléico. Para isso, foi feita a extração de ácidos nucleicos total a partir de folhas de alface com sintoma de vira-cabeça e, posteriormente foi realizado o RT-PCR utilizando os primers universais para o gênero Tospovirus. O produto do PCR foi sequenciado e avaliado nos programas Blast, ClustalW e Mega 7.0. A partir da análise da filogenia foi observado que os isolados formaram um clado com os acessos da espécie Tomato chlorotic spot virus (TCSV). Este foi o primeiro relato de TCSV em alface no Estado do Pará

The mitochondrial elongation factor LeEF-Tsmt is regulated during tomato fruit ripening and upon wounding and ethylene treatment.

A gene encoding an elongation factor LeEF-Tsmt that participates in the protein synthesis process in mitochondria shows strong expression in ripening fruit as compared to other organs. It is strongly up-regulated during the first stages of the ripening process in parallel with the climacteric rise in respiration. LeEF-Tsmt expression is stimulated by ethylene, wounding and high temperature but ethylene-insensitive mutants exhibit normal expression. Transgenic fruit have been generated in which LeEF-Tsmt has been constitutively up- and down-regulated. Surprisingly, altering the expression of the gene by genetic transformation with antisense and sense LeEF-Tsmt constructs did not affect the pattern of respiration and ethylene production during ripening and upon wounding. In addition, expression of the alternative oxidase gene which is known to play an important role in respiratory climacteric was not affected. Possible reasons for the absence of effect on respiration of variations of LeEF-Tsmt gene expression are discussed.

Nitrogen oxides and CO2 from an Oxisol cultivated with corn in succession to cover crops.

2016

Desenvolvimento de um meio semi-seletivo para a detecção de Pseudomonas syringae pv. tomato.

Desenvolveu-se um meio semi-seletivo para Pseudomonas syringae pv. tomato (Pst), objetivando seu uso em detecção do patógeno em sementes de tomate. A seletividade do meio foi obtida através de antibiogramas e testes de crescimento do patógeno, representado por 04 isolados procedentes de Guaíra, SP, Botucatu, SP, Coimbra,MG e Planaltina, GO. Também, foram comparadas diversas concentrações do agente antifúngico clorotalonil e do agente halofílico. O meio proposto tem a seguinte constituição, tendo como base o meio B de King: proteose peptona n.3, 10g; KH2PO4, 1,5g; MgSO4, 7H2O, 15g; glicerol, 10 ml; NaCl, 15 g; Clorotalonil, 200 ug/ml; agar, 15g; agua destilada, 1000 ml; acrescido dos antibioticos cefadroxil, 50 ug/ml; cefalexina, 50 ug/ml e clindamicina, 100 ug/ml. Este meio apresenta um índice de repressividade de 1,3%, alto índice de supressividade e sensibilidade de 10(2) UFC/ml de Pst.

Nodulation, gas exchanges and production of peanut cultivated with Bradyrhizobium in soils with different textures.

Nitrogen fertilization from biological source is an uncommon practice for peanut growers due to the limited results, mainly in environments with water restriction. In this study, the response of a commercial Bradyrhizobium was evaluated on the nodulation and production of peanuts grown in sandy and medium textured soils. Two experiments using different soils were carried out in the field during the dry season, in Campina Grande, Paraíba State, Brazil. Three peanut genotypes were submitted to the following treatments: 1-no nitrogen fertilization (control), 2- chemical fertilization (ammonium sulfate) and 3- inoculation with Bradyrhizobium [commercial strain BR 1405 (SEMIA 6144)]. A completely randomized 3x3 factorial design was adopted with five repetitions for both experiments. The evaluates variables were: height of the main stem, number of nodes/plant, root length, root dry weight, weight of pods/plant and number of pods/plant. In addition, gas exchanges were estimated using IRGA apparatus. Both genotypes (BRS Havana and L7 Bege) were benefited in relation to production due to an inoculation with SEMIA 6144. No physiological response was verified in genotypes or N-treatments to gas exchange, excepting for the Ci/Ca ratio in the medium textured soil experiment. BRS Havana showed low Ci/Ca ratio in Bradyrhizobium treatment, indicating that SEMIA 6144 improved the plants photosynthetic efficiency.

Effects and Modes od Action of Canopy Management Practices on Vine Physiology and Berry Composition in Organically-Cultivated cv. Sangiovese (Vitis Vinifera L.)

In organic and biodynamic vineyards, canopy management practices should be carefully and timely modulated, particularly in a context of climate change, for successfully achieving balanced plants, ventilated and exposed berries, elevated grape and wine quality. In 2013 and 2014, characterized by contrasting climatic conditions, the implications of post-veraison (late) or pea-size trimming, post-veraison or pre-harvest late defoliations and shoot-positioning (post-veraison) were assessed against long-shoots non treated controls, under field conditions on organically-cultivated cv. Sangiovese. The key agronomic and enological relevance of late trimming and defoliations clearly emerged in both seasons. Berry skin phenolics (e.g. anthocyanins, flavonols) increased markedly, without changes in technological parameters. In case of early trimming, such positive effects were observed only in 2013. Maintaining long shoots for shading decreased anthocyanins, flavonols and total phenolics concentrations and promoted the production of compact bunches. Experimental data strongly designated late trimming, a practice proved to contain yield and bunch compactness, as a valuable alternative to cluster thinning. Late trimming, defoliations and shoot positioning reduced the severity of Botrytis cluster rot. The highest levels of berry skins phenolic compounds in late trimmed and defoliated plants could have contributed control the severity of this pathogen. The enological benefits induced by late trimming and defoliations and shoot positioning emerged in both young and aged wines. For the first time, cell cultures from cv. Sangiovese berry tissues were obtained and enabled to investigate, in controlled conditions, the relations between mechanisms regulating secondary metabolism in grapevine cells and changes induced by environmental and agronomic factors. The Doctoral Dissertation strongly highlights the need to consider, for a proper interpretation of the multiple modifications induced by canopy management strategies, physiological mechanisms other than the canonic source-sink relationships, in particular their impact on the vine hormonal status.

Anti-metabolic effects of Galanthus nivalis agglutinin and wheat germ agglutinin on nymphal stages of the common brown leafhopper using a novel artificial diet system

The common brown leafhopper, Orosius orientalis (Matsumura) (Homoptera: Cicadellidae), previously described as Orosius argentatus (Evans), is an important vector of several viruses and phytoplasmas worldwide. In Australia, phytoplasmas vectored by O. orientalis cause a range of economically important diseases, including legume little leaf (Hutton & Grylls, 1956), tomato big bud (Osmelak, 1986), lucerne witches broom (Helson, 1951), potato purple top wilt (Harding & Teakle, 1985), and Australian lucerne yellows (Pilkington et al., 2004). Orosius orientalis also transmits Tobacco yellow dwarf virus (TYDV; genus Mastrevirus, family Geminiviridae) to beans, causing bean summer death disease (Ballantyne, 1968), and to tobacco, causing tobacco yellow dwarf disease (Hill, 1937, 1941). TYDV has only been recorded in Australia to date. Both diseases result in significant production and quality losses (Ballantyne, 1968; Thomas, 1979; Moran & Rodoni, 1999). Although direct damage caused by leafhopper feeding has been observed, it is relatively minor compared to the losses resulting from disease (P Tr E bicki, unpubl.).

Cyclic strain disrupts endothelial network formation on Matrigel

Most forms of tissue healing depend critically on revascularisation. In soft tissues and in vitro, mechanical stimuli have been shown to promote vessel-forming activity. However, in bone defects, increased interfragmentary motion impairs vascular regeneration. Because these effects seem contradictory, we aimed to determine whether a range of mechanical stimuli exists in which angiogenesis is favoured. A series of cyclic strain magnitudes were applied to a Matrigel-based “tube formation” assay and the total lengths of networks formed by human microvascular endothelial cells measured at 24 h. Network lengths were reduced at all strain levels, compared to unstretched controls. However, the levels of pro-angiogenic matrix metalloproteases-2 and -9 in the corresponding conditioned media were unchanged by strain, and vascular endothelial growth factor was uniformly elevated in stretched conditions. By repeating the assay with the addition of conditioned media from mesenchymal stem cells cultivated in similar conditions, paracrine stimuli were shown to increase network lengths, but not to alter the negative effect of cyclic stretching. Together, these results demonstrate that directly applied periodic strains can inhibit endothelial organisation in vitro, and suggest that this may be due to physical disruption rather than biochemical modulation. Most importantly, the results indicate that the straining of endothelial cells and their assembly into vascular-like structures must be studied simultaneously to adequately characterise the mechanical influence on vessel formation.

Cate Consandine

The interpretation of evidence dominates contemporary television crime shows. Inanimate objects and disparate facts are made to speak; technology and expert opinion wring out their stories. In examining these dead pieces of evidence, the investigators search for patterns, discovering living perpetrators and fugitives. Psychology comes in where the evidence is interpreted; the investigators try to think through perpetrators' minds and presumably perverse rationales. Objects are examined. Banal things become precious, put into bags, marked, date- and time-stamped, and stepped around carefully. After a crime, the objects involved are different. After a crime show, our gaze is different; everything is potentially incriminating, perverse. Bags without people don't make sense. Under this gaze, objects acquire a psychology. When we look at a crime scene, the evidence violates us. The work of Melbourne artist Cate Consandine is about objects and how they occupy the space that they occupy. In her practice as a sculptor and throughout her studies at the Victorian College of the Arts, the Sydney College of the Arts, and now Monash, her work has cultivated violent ambiguity. Consandine's work extends across a range of different media, particularly vidoe, objects and spaces. Like a crime show, it activates a particular type of inquisition from the viewer.