521 resultados para Aging of seeds
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The staining pattern of peanut (Arachis hypogaea L.) seeds with a tetrazolium solution was evaluated to determine the adequate conditions of seed quality evaluations. Three seed lots with different vigour levels and similar moisture content were pre-conditioned using the combination of five periods of time (4, 8, 12, 16 and 20 hours) and four temperatures (20, 25, 30 and 35 degrees C) and then exposed to a 1.0% tetrazolium solution for three hours. The moisture content levels of seeds conditioned for 8 hours at the temperatures of 25, 30 or 35 degrees C, for 12 hours at 20 or 25 degrees C and for 16 hours at 20 degrees C, were above 30%. In this range of moisture level, the staining in tetrazolium was clear and uniform, reflecting an appropriate conditioning of the seeds. However, under a practical point of view, the period of 16 hours at 20 degrees C showed to be the best option, since it allows to start the pre-conditioning an late afternoon of one day and submit the seeds for staining in the following morning.
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Wheat (Triticum aestivum L.), Anahuac cultivar, were treated with six triadimenol (0,0; 12,5; 25,0; 37,5; 50,0 and 62,5 g of a.i./100 kg of seeds) and tebuconazole (0,0; 7,5; 15,0; 22,5 30,0 and 37,5 g of a.i./100 kg of seeds) dosis to reduce the subcrown internode length and then to deep the point of emission of adventitious roots. Seeds were seeded in pots with soil, with 5 cm of depth and after two weeks the seedlings number was counted and the subcrown internode length (CM) was evaluated. The CM may be represented by the equations: a) CM = 4,49 - 0,1779 x + 0,002161 x2 (r2 = 0,9247); b) CM = 4,62 - 0,29948 y + 0,006480 y3 - 0,00004622 y3 (r2 = 0,9551), where ''x'' and ''y'' represent tebuconazole and triadimenol dosis, respectively. The CM showed minimum values for triadimenol dosis equal to or higher than 37,5 g a.i./100 kg of seeds and for tebuconazole decreased continuously with the increase of the product dosis, showing values near to 1 cm for the maximum dosis. The triadimenol allowed, at suitable dosis, almost total inhibition of the wheat seedlings subcrown internode with no effects on seedling emergence and initial growth.
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The germination of seeds of Bidens pilosa L. colected at different places was analyzed by dose-response curves for induction and reversion of germination in seeds pre-incubated at 25 degrees C or 36 degrees C during 24 hours. Our results indicate that phytochrome is responsible for the control of seed germination id Bidens pilosa and the level of pre-existing active form of phytochrome (Pfr) above the threshold switch the seed to germinate in darkness.
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This study was undertaken to investigate the toxic effect of Crotalaria spectabilis seeds added to the ration for commercial broilers during the final phase of growth. Ground seeds were added at different concentrations to the ration: 0.0% (control), 0.01%, 0.1% and 0.4%. Rations containing 0.4% caused symptoms of intoxication, beginning in the second week of the study. During the third week birds showed bristling, apathy, general weakness, distended abdomen and agglomeration. In the fourth week, four animals died. Necropsy revealed prominent ascites and severe lesions of liver, kidney and lung. Microscopic examination revealed necrosis of hepatocytes, inflammatory cell infiltration, hypertrophy and hyperplasia of biliary duct cells leading to atresia and cholestasis. Prominent cartilaginous and osseous nodules in the lungs were also present as well as degenerative, changes in the kidney tubules and necrosis of cells of the bursa. All the broilers receiving a ration with 0.1% of Crotalaria seeds showed ascites and slight lesions of the liver. The remaining groups showed no reduction in weight gains, lesions or clinical symptoms. It is concluded that broilers during the final phase of growth are sensitive to administrations of seeds of C. spectabilis in their ration. The presence of ascites and cartilaginous and osseous nodules in the lungs of the affected birds was also considered important.
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the aim of this study was to evaluate the allelopathic effect of soil samples collected under the canopies of three specimens of Copaifera langsdorffii the germination of Lactuca sativa and survey the natural seed bank according to seasonality. To test the allelopathic effect was carried experiments of pre and post-emergence with seeds of L. sativa and to quantify the stock of seeds, soil samples were collected from three specimens at three distances from the stem (1, 2 and 3 m) and at three depths (0-5, 5-10 and 10-15cm) in the region of savanna in the dry and wet seasons. The samples tested in bioassay of pre-emergence no significant influence on germinability, mean germination time and mean germination speed, but showed a difference in the synchronism of germination, these data were independent of sampling station. In test for post-emergence was observed statistical difference in the parameters evaluate (length of primary roots and hypocotyls) in both seasons. To quantify the natural seed bank were macroscopic analysis of each soil sample with the help of stereoscopic microscope. The analysis of the natural seed bank showed a larger number of seeds in the 0-5cm and in distance of 2m for both seasons. The results suggest the presence of allelochemical substances in soil samples collected under the canopy of Copaifera langsdorffii.
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The inoculation of soybean crop with Bradyrhizobium bacteria is a widespread practice, due to excellent results achieved in productivity, however, some doubt still arise in relation the need of application of mineral nitrogen at sowing. In that mean, this work aimed to evaluate the response of the doses at inoculant and mineral nitrogen in the sowing of crop soybean in area of first cultivation. The experiments were carried in the experimental field of the University of the Estate of Mato Grosso, Campus of Alta Floresta - MT, Brazil, in the growing seasons of 2006/2007 and 2007/2008. The experimental design was randomized blocks, in a factorial escheme 2 x 4, with four replications. The factors consisted in the inoculation of seeds with Bradyrhizobium japonicum *(3 e 6 mL kg(-1) of seeds), and nitrogen fertilizer at sowing *(0, 10, 20 e 40 kg ha(-1)). The following variables were evaluated: plant height, insertion height of first pod, number of pod per plant, number of grain per pod, mass of 100 grain and grain productivity. In the two growing seasons there was no significant difference for doses of inoculants applied in first year of cultivation with soybean. To nitrogen application at sowing of soybean crop there was quadratic effect to plant height and of insertion height of first pod and growing linear to number of pod per plant in the second year of cultivation, however, without significant increase the productivity.
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The study aimed to evaluate the yield and fruit quality of papaya 'Sunrise Solo' as function of nitrogen and boron fertilization. The experiment had a randomized block design with four replications, two plants per plot with a single border. To make up the treatments, we used the experimental array Plan Puebla III, which set the rates for nitrogen (0.0 to 111.2 - 200 - 288.9 - 400 g plant(-1), and B (0.0 - 0.83 - 1.5 - 2.16 - 3.0 g plant(-1)), in a total of ten treatments. The addition of nitrogen increased the yield, average fruit weight and number of fruits per plant. The nitrogen and boron increased the diameter and length of the fruit, amount of seeds and content of soluble solids. The pH of the pulp decreased linearly with increasing doses of nitrogen and boron. It was observed a significant effect of N rates on the level of vitamin C.
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The onion (Allium cepa L.) belongs to the family Alliaceae, and the second vegetables in economic importance. It horticultural culture of high relevance, in central-south and in the far south, is highlighting the states of São Paulo, Rio Grande do Sul, Santa Catarina and Parana. The bulbificacion only begins when the combination of the determinants of bulbificacion (photoperiod and temperature) of each cultivar is reached. It Can be grown in tropical regions with the use of vernalization of the bulbs. The objective of this study is to identify the efficiency in the production of seed, onion depending on the cut or not the bulb before the period of vernalization. The analysis of the variables consisted: humidity; number of seeds; mass of seeds for umbel; umbels number; number of seeds for umbel; total number of flowers and of fecundated flowers; number of seeds for capsule; total mass of seeds; emergency percentage; vigor percentage; index of emergency speed and mass of 100 seeds humidity; number of seeds; mass of seeds for umbel; umbels number; number of seeds for umbel; total number of flowers and of fecundated flowers; number of seeds for capsule; total mass of seeds; emergency percentage; vigor percentage; index of emergency speed and mass of 100 seeds, using the cultivars Baia Periforme and Texas Grano. The experimental design was randomized blocks with four replicates, there was 80 plants for replicate, each parcel was conduced with 20 plants distributed in 4 lines of 5 plants with spacing of 20cm between plants and lines which was avaliated the 6 central plants. The seeds production not variated between cultivars Texas Grano e Baia Periforme. The cultivar Texas Grano showed seeds with more physiological quality. The cut or not cut of the bulbs not changed the physiological quality of the seeds. But utilization of whole bulbs resulted more yield of seeds with more flowers number and fertilized flower in Baia Periforme, more value of the total mass of seeds, number of seeds by plant and number and mass of seed by umbel in two cultivars.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Compost and vermicompost, produced from organic fraction of municipal solid wastes were studied as components of potting media for Licania tomentosa (oiti) seedlings production. The objective was to achieve data to amplify the utilization of these products, in order to utilize them to ornamental and urban arborization species. Increasing rates of organic fertilizers were used until the total soil substitution from the potting media. There were no fitotoxic effects. Compost or vermicompost caused higher germination index of seeds and higher growth of plants. The study demonstrated that it is possible to utilize these products in other activities beyond aplication in agricultural soil, and it can generate new markets to this kind of organic fertilizer.
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An experiment was conducted to study alfalfa (Medicago sativa L.) yields as affected by row spacings of 15, 20, 30 and 40 cm and plant densities originated from 10, 15, 20 and 30 kg/ha of seeds. The experiment was conducted on a Typic Eutrortox (Clay) in Bandeirantes, state of Paraná, Brazil. The experimetal design was a 4 × 4 factorial in randomized triplicated blocks. There was no significant effect of row spacings and plant populations on plant height and dry matter production. The 15 cm row spacing showed higher number of stems throughout the two years of the experiment. Up to the 6th cut the plant density of 30 kg/ha also lead to a higher number of stems/ha.
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A field experiment was carried out to study the effects of liming and time of harvesting on peanut cv. Botutatu (Arachis hypogaea L.) seed yield and yield components in the period of July, 1991 to February, 1992, in São Manuel, State of São Paulo. The soil was a Dark Red Latosol (Hapludult, sandy loam), and the experimental design was a subplot replicated four times in completely randomized blocks. Lime levels (0.0 and 1.75 t/ha) were applied in the plots, and the subplots were nine weekly harvests, starting at 87 days after planting (DAP). There was no effect of lime on hulls or seed yield and on peanut yield components. The germination of seeds in hulls was incresead at each harvest and was lower at lime presence. The highest yield was observed at 129 DAP.
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Fruits of okra (Abelmoschus esculentus (L.) Moench.) cv. Amarelinho were harvested at three times: 35, 45 and 55 days after anthesis. Half part of the fruits of each harvest time was shelled and the seeds were dried in natural environment of laboratory or in dry chamber. The other half was dried unshelled in the same two conditions. Water contents of seeds were evaluated at harvest time and before the germination test, that was carried out when the seeds were in hygroscopic equilibrium with the two environments. The physiological quality of seeds was affected by the interaction effects of fruit age, drying method and drying condition. The highest values for percentage of germination were obtained from seeds taken from fruits 55 days old (up to 92%) and the hard seeds percentage was not affected by drying method and drying condition. The seeds from fruits of 35 and 45 days old had the germination percentage increased when dried inside the fruit in natural environment.