Degradabilidade do capim-elefante em diferentes estágios de maturidade avaliada pelo método in vitro/gás

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gibberellin and cytokinin effects on soybean growth

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fermentation and epiphytic microflora dynamics in sugar cane silage

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Método de aplicação do ácido indolbutírico na estaquia de cultivares de pessegueiro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da influência de cargas verticais sobre diferentes rodas compactadoras no ciclo de semeadura do milho

Assim como outras culturas de origem tropical, o milho exige durante o seu ciclo vegetativo, calor e umidade para se desenvolver, e as condições de instalação da cultura podem definir uma boa ou má produção. O objetivo deste trabalho foi avaliar a influência de cargas verticais sobre rodas compactadoras no ciclo da cultura do milho. Este trabalho foi conduzido nas Faculdades Associadas de Uberaba - FAZU, no município de Uberaba (MG), e instalado no delineamento em blocos ao acaso com três modelos de rodas compactadoras e três cargas verticais com duas repetições, na Pista de Ensaios de Semeadura, constituída de canais de solo. Observou-se que o número de dias para emergência, altura de plantas, número de folhas e a produção não foram afetados significativamente para os tratamentos estudados.

Inibidor da ação do etileno na conservação pós-colheita de Chrysanthemum morifolium Ramat cv. Dragon

A durabilidade e a qualidade pós-colheita de flores de corte são atributos fundamentais na sua valoração ao longo da cadeia produtiva e na satisfação dos consumidores. Objetivou-se, nesta pesquisa, verificar o efeito do tiossulfato de prata, associado ou não à sacarose, na manutenção da qualidade pós-colheita de hastes de crisântemos (Chrysanthemum morifolium Ramat cv. Dragon) . O experimento foi conduzido sob delineamento inteiramente casualizado, em esquema fatorial testando soluções de manutenção com tiossulfato de prata (STS), sob cinco níveis (Água destilada; STS a 0,2 mM; STS a 0,2 mM + sacarose a 50 g L-1; STS a 0,4 mM; STS a 0,4 mM + sacarose a 50 g L-1); e data de amostragem, por três níveis (0; 3; 6 dias). Utilizaram-se três repetições com duas hastes florais em cada tratamento. Foram feitas avaliações físicas: coloração, massa fresca e conteúdo relativo de água (CRA); avaliações químicas: açúcares redutores e pigmentos; e avaliações qualitativas: turgescência, cor das flores, e número de botões, flores entreabertas e abertas. O tratamento com 0,2 mM de STS possibilitou melhor manutenção da massa fresca das hastes. A concentração de pigmentos e carboidratos redutores foi maior naqueles tratamentos em que a sacarose foi associada. A coloração e o conteúdo relativo de água foram favorecidos nos tratamentos STS a 0,2 e 0,4mM. A concentração de 0,2 mM de STS foi a que obteve os melhores resultados, prolongando a vida de vaso das hastes. A qualidade das hastes foi superior, tendo as melhores avaliações de conteúdo de água, cor e turgescência.

Características morfogênicas e estruturais do capim-marandu manejado sob pastejo intermitente com diferentes ofertas de forragem

Avaliaram-se as características morfogênicas e estruturais do dossel de Brachiaria brizantha, cv. Marandu, sob pastejo intermitente no período chuvoso, em diferentes ofertas de forragem e ciclos de pastejo. O delineamento experimental foi em blocos ao acaso, em esquema de parcelas subdivididas, com três repetições. Nas parcelas, avaliou-se o efeito das ofertas de forragem (4, 7, 10 e 13% do PV/dia) e, nas subparcelas, o efeito dos ciclos de pastejo. Todas as variáveis diferiram entre os ciclos de pastejo, comprovando grande influência das condições ambientais sobre as características avaliadas. A taxa de alongamento do colmo e a altura do dossel responderam linear e positivamente ao aumento da oferta de forragem. O número de perfilhos vegetativos nos piquetes com a menor oferta permaneceu constante ao longo de todo o período experimental, no entanto, nos piquetes com as demais ofertas, atingiu valores mais elevados nos ciclos intermediários. A densidade de perfilhos reprodutivos e totais ajustou-se ao modelo quadrático de acordo com a oferta de forragem. Pastos manejados com ofertas de forragem próximas a 4% PV/dia têm menor alongamento de colmos e tendem a reduzir as perdas por senescência. As variáveis ambientais exercem maior influência sobre as características morfogênicas e estruturais em comparação a ações de manejo como a oferta de forragem.

Study of some Brazilian Myrtaceae in Jaboticabal sp

The family Myrtaceae is one of the most important related to fruit species. In Brazil it encloses more than 100 species of native fruit from North to South of the country (Giacometti, 1992; Donadio, 1992; Mattos, 1992). The genus Eugenia, Campomanesia, Psidium and Myrciaria are the most important, grouping most of the species of some importance. The germplasm bank of the Universidade Estadual Paulista includes some of the major species. Some characteristics are typical for most of the Myrtaceae fruit species. The most relevant are the long juvenile period presented by the trees, taking long time to produce, when propagated by seed; the slow growing tree behavior; difficult to propagated by vegetative means; large variability in trees obtained by seed propagation. The cited characteristics are commented for some species as well as the fruit quality, from data obtained in trees at the same ecological conditions.The species evaluated are: 1) Eugenia stipitata Mc Vaugh; 2) Eugenia tomentosa Cambes; 3) Eugenia brasiliensis Lam.; 4) Eugenia uniflora L.; 5) Eugenia luchsnathiana Berg.; 6) Eugenia uvalha Cambess; 7) Camponesia spp; 8) Plinia edulis (Veil. Sobral); 9) Eugenia involucrata D.C.; 10) Psidium acutangulum Mart.; 11) Myrciaria dubia Mc Vaugh; 12) Engenia guabiju Berg. The main conclusions based on the data analysed are: the fruits of some species present good general characteristics, mainly for fresh consumption, as high Vitamin C, sugars, pulp and other characteristics; 'Araca-boi' presents some good fruit characteristics, but is more adapted for processing, by its high acidity; Some species present low % of edible portion and need to be improved to gain commercial acceptance. mainly the 'cabeludinha' and 'cambuca'.

Essential oil of the Pothomorphe peltata (L.) Miq.

The essential oils of leaves of the Pothomorphe peltata (L.) Miq., collected in vegetative and reproductive periods, showed yields of 0.10-0.20%. Analysis of the oil by GC/MS revealed that the predominant components were those of the sesquiterpene class. The major constituents were beta-caryophyllene (39.5-68.0%), germacrene D (6.2-13.3%), (E)-nerolidol (4.8-11.1%) and alpha-humulene (2.1-6.5%).

Nitrogen redistribution to sorghum grains as affected by plant competition

An experiment was conducted to study nitrogen absorption and translocation in grain sorghum plants during their reproductive growth. Sorghum was grown in four row spacings: 50 and 70 cm in single rows, 80 and 120 cm in double rows 20 cm apart. Plant populations were 71000, 142000 and 213000 plants/ha. After flowering, samples were taken at 12 day intervals, and the plants were divided into grains and stover, where N was analyzed. There was an increase in N concentration in lower plant populations and in wider row spacings. However, total nitrogen accumulation (in kg/ha) increased as the number of plants was increased. In the vegetative parts of the plants there were higher N concentrations in lower populations showing that there was a higher N absorption and a lower translocation to the grains. When grain sorghum was grown in 50 cm rows, there was a high N accumulation, a high N translocation to the grains and the highest yield. This row spacing led to the highest N use efficiency.

SYSTEMATICS OF FRESH-WATER AUDOUINELLA (ACROCHAETIACEAE, RHODOPHYTA) IN NORTH-AMERICA .1. THE REDDISH SPECIES

Multivariate morphometrics and image analysis were used to determine the number of well-distinguished infrageneric taxa of reddish freshwater Audouinella in North America. Three distinct groupings were differentiated from 83 populations collected from Alaska and Labrador in the north to central Mexico and Jamaica in the south. These groupings were statistically related to seven type specimens. The following species were recognized: A. eugenea (SKUJA) JAO, A. hermannii (ROTH) DUBY [syn.: A. violacea (KUTZ.) HAMEL and its varieties, alpina (KUTZ.) RAB., dalmatica (KUTZ.) RAB., expansa (WOOD) SMITH, and hercynica (KUTZ.) KUTZ.] and A. tenella (SKUJA) PAPENFUSS. These species are separated based on dimensions of vegetative cells and monosporangia. A. tenella is found only in California, A. eugenea in warm, alkaline and high-ion waters of the tropical rainforest and desert-chaparral, while A. hermannii occurs widely from the boreal to south temperate and in waters with relatively low temperatures and ion content.

Mechanism of micronuclei formation in polyploidizated cells of Allium cepa exposed to trifluralin herbicide

The trifluralin is an agent that promotes a cellular damage due to its direct action on the microtubules. This action leads to a decontrol in the cellular division, bringing about polyploid cells. In this work, we show the evidences that the exceeding genetical material of theses polyploidizated cells tends to be eliminated from the nucleus in the form of micronucleus. Our analyses prove this fact, both by the presence of a number of cells carrying micronucleus, and by the evidences of the elimination of the exceeding material itself, after exposition of the Allium cepa root tips tested with several concentration of trifluralin herbicide. It was noticed that the residual concentration induced a number of polyploid cells, micronuclei and mini cells. Inferences about the implications of the elimination of genetic material from micronuclei, such as cell viability and apoptosis, are also presented. (c) 2007 Elsevier B.V. All rights reserved.

EXTRAFLORAL NECTARIES IN THE TROPICAL TREE GUAREA-MACROPHYLLA (MELIACEAE)

This paper describes the anatomy and morphology of the complex nectary systems of the tropical tree Guarea macrophylla Vahl (Meliaceae) and presents the first record of extrafloral nectaries occurring on reproductive organs (fruits) of a member of the order Sapindales. The extrafloral nectaries of G. macrophylla occur on petioles, petiolules, the abaxial surface of all leaflets, leaf buds, and over the surface of fruits. All extrafloral nectaries are distinctly raised above the surface. Foraging ants collect extrafloral nectar on Guarea trees both day and night. We suggest that the presence of extrafloral nectaries might be a useful taxonomic character for the identification of Guarea species.

Morpho-anatomical aspects of Paepalanthus hilairei Koern (Eriocaulaceae) from Serra do Cipo MG

The morphological characteristics of seedlings and the anatomical characteristics of vegetative organs and floral scape of P. hilairei (Eriocaulaceae) were analyzed to investigate the ecological and taxonomic implications for the species. P. hilairei is a perennial plant with an aerial stem and it grows in recently decomposed stony, sandy soils of the Serra do Cipo, in the State of Minas Gerais, Brazil. It is found both on wet and dry soils, exposed to constant winds, high light intensities and extreme daily fluctuations of temperature. The results show that the seeds have operculum and the initial seedling development stages are the same for other Eriocaulaceae. During the germination period, the undifferentiated axis of the embryo becomes apparent. The observation of the development of this axis, shows first, the growth of the leaves and later that of the adventitious root. Attention is focused on the apical stem region which presents sterelis lateral branching with adventitious roots in its base which will develop into paraclades (system of florescences). Both of them rise out of the pericycle and characterize its vegetative growth. The occurrence of a special leaf substomatal chamber may be related to an efficient protection for the gaseous exchange and may be considered an important characteristic of the Eriocaulaceae.

Genomic organization of the Neurospora crassa gsn gene: possible involvement of the STRE and HSE elements in the modulation of transcription during heat shock

Glycogen synthase, an enzyme involved in glycogen biosynthesis, is regulated by phosphorylation and by the allosteric ligand glucose-6-phosphate (G6P). In addition, enzyme levels can be regulated by changes in gene expression. We recently cloned a cDNA for glycogen synthase (gsn) from Neurospora crassa, and showed that gsn transcription decreased when cells were exposed to heat shock (shifted from 30degreesC to 45degreesC). In order to understand the mechanisms that control gsn expression, we isolated the gene, including its 5' and 3' flanking regions, from the genome of N. crassa. An ORF of approximately 2.4 kb was identified, which is interrupted by four small introns (II-V). Intron I (482 bp) is located in the 5'UTR region. Three putative Transcription Initiation Sites (TISs) were mapped, one of which lies downstream of a canonical TATA-box sequence (5'-TGTATAAA-3'). Analysis of the 5'-flanking region revealed the presence of putative transcription factor-binding sites, including Heat Shock Elements (HSEs) and STress Responsive Elements (STREs). The possible involvement of these motifs in the negative regulation of gsn transcription was investigated using Electrophoretic Mobility Shift Assays (EMSA) with nuclear extracts of N. crassa mycelium obtained before and after heat shock, and DNA fragments encompassing HSE and STRE elements from the 5'-flanking region. While elements within the promoter region are involved in transcription under heat shock, elements in the 5'UTR intron may participate in transcription during vegetative growth. The results thus suggest that N. crassa possesses trans-acting elements that interact with the 5'-flanking region to regulate gsn transcription during heat shock and vegetative growth.