Vandeir Francisco Guimarães

Rapid identification of bacterial isolates from wheat roots by high resolution whole cell MALDI-TOF MS analysis.

Whole-cell mass spectrometry analysis is a powerful tool to rapidly identify microorganisms. Several studies reported the successful application of this technique to identify a variety of bacterial species with a discriminatory power at the strain level, mainly for bacteria of clinical importance. In this study we used matrix-assisted laser desorption ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) to assess the diversity of wheat-associated bacterial isolates. Wheat plants cultivated in non-sterile vermiculite, under greenhouse conditions were used for bacterial isolation. Total cellular extracts of 138 isolates were analyzed by MALDI-TOF MS and the mass spectra were used to cluster the isolates. Taxonomic identification and phylogenetic reconstruction based on 16S rRNA gene sequences showed the presence of Pseudomonas, Pantoea, Acinetobacter, Enterobacter and Curtobacterium. The 16S rRNA gene sequence analyses were congruent with the clusterization from mass spectra profile. Moreover, MALDI-TOF whole cell mass profiling allowed a finer discrimination of the isolates, suggesting that this technique has the potential of differentiating bacterial isolates at the strain level.

Physiological maturity of seeds and colorimetry of fruits of Jatropha curcas L.

The objective was to relate the coloration of fruits of Jatropha curcas L during the maturation process with morphometric (fruits and seeds) and germinative characteristics (seeds). Fruits were collected at various maturation stages from mast trees located in Eldorado/MS, and six maturation stages were visually classified based on fruits epicarp color. Epicarp digital colorimetry was used to characterize maturation stages in addition to morphometric variables of length and width of fruits and seeds, as well their water content. For determining the physiological potential it was used germination test, emergence velocity index and first count of germination. Results indicated that seeds of J. curcas should be harvested when fruit epicarp shows a reading equal or smaller than 82, 70 or 65 nm of red, green or blue scales from a digital color analyzer. Seeds of fruits with that colorimetry can be harvested in virtue of the maxim acumululation of dry mass, water content below 38,5% and higher physiological potential.

Curva de absorção de água em sementes de atemóia (Annona cherimola Mill. x Annona squamosa L.) cv. Gefner

ABSTRACT - The present study aimed to characterize the water absorption curve in atemoya seeds ( Annona cherimola Mill x Annona squamosa L.) cv. Gefner, submitted to three imbibitions methods: seeds submerged in distilled water (MSSA), seed placed betwen paper fil ter imbibed withdistilled water inside a gerbox box (MPEA) and standard test, with seeds kept in roll of filter paper moistened with water (MTP ). The experimentaldelineation was entirely randomized, with 6 treatments and 4 repetitions of 25 seeds per parcel. The treatments were submitted to three imbibitionsmethods, with live and deth seeds. The imbibition time among 27, 34 and 47 hours, in the MTP, MPEA and MSSA methods represented an indicativefor seeds treatment, which could possibly function as a minimal time needed for imbibition in solution with vegetal regulators. The MTP and MPEAwere the methodologies that provided a better curve characterization, with changes between phases I and II after 27 and 34 hour s, and reaching thephase III after 234 hours, which suggests the immersion time for seeds treatments.

Adubação nitrogenada associada à inoculação com Azospirillum brasilense e Herbaspirillum seropedicae na cultura do milho

Bacteria of the genera Azospirillum and Herbaspirillum have the ability to fix atmospheric nitrogen (N) and promote plant growth. The aim of this study was to evaluate the development and productivity of maize in response to inoculation with A. brasilense and H. seropedicae associated to N fertilizer. The experimental design was a randomized complete block with four replications and treatments arranged in a 4 x 5 factorial. The treatments consisted of inoculation of seeds (control, strain of A. brasilense - Ab-V5, strain of H. seropedicae - SmR1 and combination SmR1+Ab-V5) and N levels (0, 40, 80, 120 and 160 kg N ha-1). The basal diameter of stem, plant height, shoot dry weight and leaf area were evaluated at the vegetative and reproductive stages, and productivity. Nitrogen fertilization promoted the development of the crop until maximum nitrogen dose studied. The combined inoculation of strains of A. brasilense (Ab-V5) and H. seropedicae (SmR1) provided increments of 12% dry weight of shoot and 7% in grain yield compared to the control, indicating benefits of the combination of diazotrophic bacteria that interact differently with the plant.

Produtividade e qualidade de sementes de soja em função de estádios de dessecação e herbicidas

The objective of this work was to evaluate the best time to apply desiccants to allow earlier harvesting without compromising seed quality and yield of soybean plants. The experiment was arranged in a randomized block design in a factorial scheme (3x3) + 1, with four replications. One factor was composed of the desiccant herbicides paraquat, glufosinate ammonium, and glyphosate at doses of 400, 400, and 960 g a.i. ha-1, respectively. The other factor was constituted of three phenological herbicide application stages (R6, R7.2, and R8.1). Harvest anticipation, mass of 100 seeds, yield, germination, and seed vigor were evaluated. The use of herbicides combined with the phenological application stages allowed to anticipate harvest from one to six days. Desiccation of the soybean plants in pre-harvest using herbicides at different phenological stages did not affect yield. Glufosinate ammonium reduced the germination of soybean seeds when applied at R6. Glyphosate reduced the vigor of soybean seeds when applied at R6 and R7.2.

Germinação de sementes de atemoia (Annona Cherimola Mill. x A. squamosa L.) cv 'Gefner' submetidas a tratamentos com ácido Giberélico (GA3) e ethephon

ABSTRACT - The aim of this work was to evaluate the effect of gibberellic acid (GA 3 ) and ethephon, besides the interaction of both plant growth regulators, on the germinative process of atemoya seeds (Annona cherimola Mill. X A. squamosa L.), cultivar ‘Gefner’. Experimental design was completely randomized, in a 5 2 factorial arrangement; treatments consisted of the combination among five GA 3 (gibberellic acid) and five ethephon concentrations, totaling 25 treatments, with four replicates of 25 seeds per plot. GA 3 concentrations were 0, 250, 500, 750, and 1000 mg L -1 i.a., whereas those of ethephon were 0, 25, 50, 75, and 100 mg L -1 i.a. Seeds were treated with both plant growth regulators through immersion in the different solutions for 36 h. Then, seeds were sown onto germitest paper roll and allowed to germinate in a germination chamber, in the dark and under 20oC/8h-30oC/16h alternate temperature. Germination percentage, time and speed index; normal seedling percentage; and dormant seed percentage were evaluated. There was an interaction of both plant growth regulators on the germinative process of atemoya seeds, which indicates that the germination percentage of atemoya seeds (Annona cherimola Mill. X A. squamosa L.), cultivar ‘Gefner’, increases by using 778 mg L

Leaf heliotropism in Styrax camporum Pohl from the Brazilian cerrado: distinct gas exchange and leaf structure, but similar leaf temperature and water relations

Styrax camporum e uma especie arbustiva comum dos cerrados do Estado de Sao Paulo, Brasil. Embora suas folhas nao tenham pulvino morfologicamente delimitado, as folhas apicais sao orientadas paralelamente a incidencia da radiacao solar (folhas paraheliotropicas), especialmente as 1200 h. Folhas horizontais estaticas das partes basais dos ramos sao orientadas perpendicularmente aos raios solares (folhas diaheliotropicas). O significado ecofisiologico do fenomeno nao foi ainda completamente elucidado. Investigou-se como o paraheliotropismo influencia a assimilacao diaria de CO2 (A) e outras taxas de trocas gasosas, relacoes hidricas, temperatura foliar (Tf) e suas relacoes com a estrutura da folha, avaliada por suas descricoes anatomicas. Folhas paraheliotropicas apresentaram maiores A e condutância estomatica (gs), o que levou a maior taxa de transpiracao (E) durante grande parte do dia. Todavia, nao houve dados categoricos assegurando que estas respostas tenham determinado menor Tf para as folhas verticais, que ocorreu apenas as 1100 e 1600 h. Nao houve nenhuma indicacao de que Tf influenciou A, E ou gs. Entretanto, folhas diaheliotropicas nao assimilaram menos carbono por causa de estomatos mais fechados. Ambos os tipos foliares atingiram abertura estomatica satisfatoria e a mesma zona de resposta de gs resultou em concentracoes de CO2 intercelular similares. Folhas paraheliotropicas tiveram maior A sob elevadas irradiâncias, sugerindo evitacao a elevada irradiância. Em ambos tipos de folhas, observou-se parenquima esponjoso compacto, representando maior capacidade fotossintetica por unidade de area foliar. O paraheliotropismo de S. camporum nao parece estar relacionado ao controle da temperatura foliar, mesmo no estressante habitat do cerrado Brasileiro.

Características agronômicas do trigo em função de Azospirillum brasilense, ácidos húmicos e nitrogênio em casa de vegetação

The objective of this study was to investigate the effect of the combined use of Azospirillum brasilense, humic acid and different levels of nitrogen on agronomic characteristics of wheat under greenhouse conditions. The experiments were installed on May 21, 2011 and proceeded to harvest on September 13, 2011. The experimental design was a randomized complete block in a 4 x 4 factorial design with four replications. The first factor relates to the combination of strain Ab-V5 of A. brasilense with humic acids, with the following treatments: control, Ab-V5, humic acid and Ab-V5 + humic acid and the second factor refers to nitrogen levels (0, 30, 60 and 90 kg ha-1 N). Most variables in the analysis had a positive linear effect of treatments depending on nitrogen fertilization, and only for variable weight of hundred grains, the negative effect was linear. There were no significant differences between the variances in grain production. It was concluded that the combined use of Ab-V5 + humic acid promotes the production mainly of dry leaves and are not responsive to nitrogen fertilizer for other productive components under study, as well as grain yield.

Produtividade de grãos e componentes de produção da canola de acordo com fontes e doses de nitrogênio

The objective of this work was to evaluate the response of canola to nitrogen sources and rates applied at sowing. The experiment was carried out on a dystroferric Red Ferralsol, with a very clayey texture. A randomized complete block design was used, in a 7x2 factorial arrangement, with seven N rates applied on soil surface at sowing (0, 20, 40, 60, 80, 100, and 120 kg ha-1), two N sources (ammonium sulfate and urea), and four replicates. The experiment was carried out with the Hyola 61 hybrid for two years, and the following variables were evaluated: plant height, number of plants per square meter, shoot dry matter mass, pod mass per plant, weight of a thousand grains, grain yield, and protein and oil contents in seeds. The variables were not affected by the N sources. The highest grain yield is obtained with 88 kg ha-1 N. Increasing N rates increase protein contents and reduce oil contents in canola seeds.

Storage of physic nut seeds in different environments and packaging

Sementes de pinhao manso (Jatropha curcas L.) possuem caracteristicas ortodoxas e requerem conhecimento sobre os fatores que afetam a manutencao de sua qualidade fisiologica. Assim, objetivou-se neste estudo identificar as condicoes adequadas de armazenamento para a manutencao da qualidade fisiologica de sementes de pinhao manso. Na avaliacao dos metodos de armazenamento, utilizou-se delineamento inteiramente casualizado, em esquema fatorial 3x3+1, sendo os fatores constituidos por tres embalagens (saco de papel Kraft, saco de polietileno e embalagem de vidro), tres ambientes de armazenamento (laboratorio com condicoes nao controladas, câmara refrigerada a 14 - 16 oC e refrigerador a 4-6 oC) e avaliacao inicial do material em estudo. Foram analisados os valores de teor de agua, primeira contagem de germinacao em ambiente controlado. Tambem se avaliou o indice de velocidade de emergencia, porcentagem de germinacao das sementes e Indice de Qualidade de Dickson para as mudas apos 45 dias da semeadura em ambiente propagativo nao controlado. As sementes armazenadas em embalagem de vidro e ambiente de geladeira mantiveram a sua qualidade fisiologica, podendo ser armazenadas pelo periodo de 180 dias.