985 resultados para Ascospores and germination


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Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV

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Forest species with economic potential, such as aroeira (Schinus terebinthifolius Raddi.), require selection of individuals with superior characteristics for use in forest restoration projects and for establishment of commercial plantations. These plantations can contribute to the sustainability of natural populations of species in the remaining forest fragments, in areas of permanent preservation, legal reserves or other areas of ecological significance. It was evaluated the fruits' yield, morphometry and viability of seeds from 15 individuals of aroeira, collected in different fragments in the region of Lower São Francisco river, Sergipe State. The fruit yield was estimated by Fornier's intensity index, and the morphometric characteristics were obtained with a digital paquimeter and analytical balance. The viability and vigor were evaluated by germination percentage and germination speed index (GSI), under controlled conditions. The results of fruit yield were subjected to variance analysis, and the means were compared by Tukey (p <0.05). The other variables means were compared by Scott-Knott test (p<0.05). The individuals differed in Fournier's indices (indices 1, 2, 3 and 4) and in the size of fruits and seeds. The germination varied from 0 to 83% and the GSI from 0.00 to 0.98. The phenotypic differences observed among individuals for fruit yield, and morphophysiological characteristics can be used in forest restoration and establishment of provenances/progenies tests, aiming discrimination of superior material for future commercial plantations.

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Physiological potential characterization of seed lots is usually performed by germination and vigor tests; however, the choice of a single test does not reflect such potential, once each test assesses seeds of differentiated mode. Multivariate techniques allow understanding structural dependence contained in each variable, as well as characterize groups of seed lots according to specific standards. The study aimed at evaluating variability among soybean seed lots and discriminate these lots by multivariate exploratory techniques as function of seed vigor. Experiment was performed with 20 soybean seed lots (10 lots cv. BRS Valiosa RR and 10 lots cv. M-SOY 7908 RR). Seed physiological potential was assessed by testing for: germination (standard, and under different water availability); vigor (accelerated aging and electrical conductivity); and field seedling emergence. Cluster analysis of seed lots, as well as Principal Component Analysis was performed using data obtained on all tests. Multivariate techniques allowed stratifying seed lots into two distinct groups. Principal Component Analysis showed that values obtained for variables: field seedling emergence, accelerated aging, and germination under different water availability were linked to BRS Valiosa RR; while to variables germination and electrical conductivity, were linked to M-SOY 7908 RR.

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Populations of carrot seeds with superior physiological quality and storage potential are of interest to seed companies and growers. Thus, we verified the efficiency of some tests for the selection of carrot populations with greater vigor and longevity of seeds. Seeds of 50 carrots progenies of different half-brothers from Brasilia cultivar were evaluated for the mass of one hundred seeds, the first count, germination, dormancy, accelerated aging with water and saturated NaCl solution. The seeds were stored at moisture contents of 6.1±0.3% in hermetic packaging at temperatures of 15 and 25°C for 12 months and germination was evaluated quarterly. The experimental data were evaluated for variance and phenotypic, genotypic and environmental heritability, coefficient of variation and genetic gain from selection. Selection based on the mass should not be used because it would increase the occurrence of dormancy in seeds of the next generation. The test of the first count, germination and accelerated aging in water or saline solution saturated may be used to select populations of carrot seeds of higher vigor and longevity. The estimated gain genetic selection for germination after 12 months storage at 25°C was 14%.

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

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Pós-graduação em Agronomia (Agricultura) - FCA

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Pós-graduação em Agronomia (Produção Vegetal) - FCAV

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In the seeds of pioneer plants, the application of treatments for breaking dormancy, and selection by colour and size, are strategies for obtaining seeds of less dormancy and better germination performance. The aim of this study was to evaluate the effect of the physical and physiological aspects of seeds of the tall fringe-rush (Fimbristylis dichotoma) on germination and dormancy. To do this, the seeds were submitted to the following treatments in three studies: (i) control, immersion in H2SO4 (98%, 36N) for 1 minute, immersion in KNO3 (1, 2 and 3%) for 15 minutes, seeding on a substrate moistened with KNO3 (0.2%) and exposure for 5 and 10 hours in a forced air circulation oven at 40 and 70 degrees C; (ii) classification of the seeds by colour (light and dark) and application of the following treatments: control, immersion of the seeds in H2SO4 (98%, 36N) for 1 and 2 minutes, immersion in KNO3 (5% and 10%) for 15 and 30 minutes and seeding on a substrate moistened with KNO3 (0.2%); (iii) classification by size (0.60, 0.50 and 0.40 mm) and germination on a substrate moistened with KNO3 (0.2%) or distilled H2O. The seeds were evaluated by germination test, first count and germination speed index. Moistening the substrate with KNO3 (0.2%), and heat treatment at 40 degrees C for 10 hours improve performance in seeds of the tall fringe-rush. Light-coloured seeds do not display dormancy. Medium-sized seeds of the tall fringe-rush show better performance in terms of percentage and speed of germination.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The objectives of this work were performing the biometric characterization of seed Chloroleucon foliosolum (Benth) G. P. (Lewis) from the municipality Ituaçu - BA, and analyze methods of scarification and temperature on germination. The seeds were characterized according to measurements of length, width and thickness, weight of thousand seeds, and water content. Were employed methods of scarification with sandpaper and sulfuric acid for 15 and 30 minutes, and not scarified seeds, combined with germination temperatures of 20, 25, 30 and 35 °C. Percentage and germination speed index, and percentage of primary root protrusion, abnormal seedlings, hard seeds and dead seeds were evaluated. The means of length, width and thickness was 6.03, 4.30 and 3.47 mm, respectively. The weight of a thousand seeds was 67.3 g with water content of 6.1%. Whereas the percentage germination with normal seedling, the method of scarification with sulfuric acid for 15 or 30 minutes combined to germination temperatures of 25 or 30 °C were effective in overcoming dormancy of Chloroleucon foliolosum.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Objetivou-se com este estudo avaliar diferentes métodos para a superação da dormência das sementes e a eficiência de herbicidas no controle químico de plantas de Momordicacharantia L. no estádio reprodutivo. O primeiro experimento constituiu-seem esquema fatorial 2 x 8 (duas épocas de coleta das sementes (2006 e 2007) e oito métodos de quebra de dormência: escarificação mecânica; imersão em ácido sulfúrico concentrado e a 50%; imersão em nitrato de potássio a 2%por três e seis horas; calor seco a 60°C; água quente a 60°C e uma testemunha sem tratamento). No segundo ensaio avaliou-se o controle da Momordicacharantia L. por meio de seis herbicidas distintos: Imazapic, Metsulfuron-methyl, Metribuzin, 2,4-D, Amicarbazone, Paraquat e uma testemunha sem aplicação de herbicidas. Em ambos os ensaios, o delineamento experimental utilizado foi o inteiramente casualizados, com quatro repetições. Após a aplicação dos tratamentos,pode-se concluir que a imersão das sementes em ácido sulfúrico concentrado por 3 minutos proporcionou uma maior porcentagem e velocidade de germinação e que o herbicida Metribuzin alcançou, embora tardiamente, um controle total das plantas de melão de São-Caetano.

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O agriãozinho é uma planta daninha de grande importância em pastagens do Brasil e apresenta destacada agressividade, sendo seu controle, portanto, desejável para o sucesso da produção forrageira. O objetivo deste trabalho foi avaliar o controle químico de Synedrellopsis grisebachii na fase reprodutiva e as suas consequências sobre as características germinativas dos aquênios da planta daninha. Os tratamentos constaram da aplicação dos herbicidas glyphosate (100, 200, 900 e 1.800 g ha-1), paraquat (34, 68, 300 e 600 g ha-1) e triclopyr (75, 150, 667 e 1.334 g ha-1), além da testemunha sem aplicação. Foram coletados aquênios aos 15 dias após a aplicação, sendo estes submetidos ao teste de germinação, determinando-se a porcentagem e o índice de velocidade de germinação. Após 29 dias em germinação, verificou-se a viabilidade dos aquênios não germinados, através do teste de tetrazólio. A eficácia dos herbicidas foi avaliada por meio de notas visuais de controle aos 7, 14, 21 e 28 DAA. Conclui-se que para o controle total de S. grisebachii, em estádio reprodutivo, é necessária a aplicação de 1.334 g ha-1 de triclopyr. Nesse estádio, a planta apresentou grande tolerância ao glyphosate e também ao paraquat. Quanto às características germinativas da progênie, o herbicida triclopyr nas doses de 150 e 667 g ha-1 promoveu redução na velocidade de germinação e na viabilidade, enquanto o glyphosate e paraquat não proporcionaram efeito.

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Seed dispersal is one of the most important mechanisms shaping biodiversity, and animals are one of the key dispersal vectors. Animal seed dispersal can directly or indirectly be altered by invasive organisms through the establishment of new or the disruption of existing seed dispersal interactions. So far it is known for a few gastropod species that they ingest and defecate viable plant seeds and consequently act as seed dispersers, referred to as gastropodochory. In a multi-species experiment, consisting of five different plant species and four different gastropod species, we tested with a fully crossed design whether gastropodochory is a general mechanism across native gastropod species, and whether it is altered by the invasive alien slug species Arion lusitanicus. Specifically, we hypothesized that a) native gastropod species consume the seeds from all tested plant species in equal numbers (have no preference), b) the voracious invasive alien slug A. lusitanicus – similarly to its herbivore behaviour – consumes a higher amount of seeds than native gastropods, and that c) seed viability is equal among different gastropod species after gut passage. As expected all tested gastropod species consumed all tested plant species. Against our expectation there was a difference in the amount of consumed seeds, with the largest and native mollusk Helix pomatia consuming most seeds, followed by the invasive slug and the other gastropods. Seed damage and germination rates did not differ after gut passage through different native species, but seed damage was significantly higher after gut passage through the invasive slug A. lusitanicus, and their germination rates were significantly reduced.