991 resultados para conservação de sementes


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Marsh Antwren (Stymphalornis acutirostris) is restricted to the lowlands between Antonina Bay, in the coastal plain of the state of Paraná, and Itapocu river, in the northern coastal plain of the state of Santa Catarina (from 0 to c. 5 m a.s.l.). It doesn't occur continuously in this region, being found in eight populations that span over an total area of about 6,060 ha (= area of occupancy; 4,856.67 in Paraná and c. 1,200 in Santa Catarina). Nine habitat types used by the Marsh Antwren were defined, based on vegetation physiognomy, localization, dominancy of botanical species, dominant life-form and history of the region. Five of these are herbaceous (marshes), while four have an upper arboreal stratum and an herbaceous lower stratum with marsh plants. According to the classification criteria of the Brazilian vegetation proposed by the Radambrasil Project, they were classified as Pioneering Formation of Fluvial Influence, Pioneering Formation of Fluvial-marine Influence, and/or Pioneering Formation of Lacustrine Influence. They occur as patches or narrow strips ranging from 0.001 to 203.0 ha in the state of Paraná. They are found mainly in the interior of bays, in the lower courses of rivers that drain into bays, in alluvial plains, and between sand dunes in the coastal plain. Characteristic herbaceous species are cattail (Typha domingensis), bulrush (Scirpus californicus), Crinum salsum, Panicum sp. cf. P. mertensii, saw grass (Cladium mariscus) and Fuirena spp. Hibiscus pernambucensis is the characteristic bush species, and Calophyllum brasiliense, Tabebuia cassinoides, Annona glabra and Laguncularia racemosa are the characteristic arboreal species. The Marsh Antwren lives in herbaceous vegetation, but also uses bushes and branches of small tress. It has low flight capacity and a single flight of more than 25 m was never recorded. Territories of 0.25 ha were estimated in one kind of habitat (tidal marsh) (= 8 individuals per hectare) and of 3.2 ha in another one (saw grass marsh) (= 0.62 individual per hectare). The global population estimate is of about 17,700 mature individuals (13,700 in Paraná and 4,000 in Santa Catarina). The species is really under threat of extinction, mainly because of it's restricted geographical distribution and habitat loss by human activities and biological contamination caused by invasion of exotic grasses (Urochloa arrecta and Brachiaria mutica).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The common beans (Phaseolus vulgaris L.) is a fabacea sufficiently spread out in all domestic territory. However, the quality of its seeds represents one of the main causes of low productivity in the beans farmings in Brazil. The objective of this work was to evaluate physiological and sanitary seed qualities of eleven bean cultivars. The physiological seed quality was evaluated trough standard germination and vigor tests. The sanitary seed quality was evaluated through two tests: blotter test was employed to evaluate fungi incidence and Koch & Menten method was employed to observe Sclerotinia sclerotiorum (Lib) de Bary occurrence. Xamego, BRS Valente, Bambu and Pérola had the best results of physiological tests. Jalo Precoce, Roxo 90, Corrente and Aporé had no good results of vigor and germination, besides presenting the lowest indices of died seeds. Fusarium sp., Aspergillus spp., Penicillium sp., Phoma sp., Rhizopus sp. and Botrytis sp. were the fungi detected in the sanity tests.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The species Schizolobium amazonicum (Huber ex Ducke) commonly known as pinho-cuiabano or paricá, is one of the trees in Amazonian area used for plantings in degraded areas, reforestations and agroforestry systems. The present work evaluated the germinative behaviour of seeds of Schizolobium amazonicum in relation to the hydric stress, defining their levels of tolerance to those limitations in the environment. The seeds were collected from 30 trees in Alta Floresta-MT and submitted the dormancy treatment by submersion into water at 100°C for 1 minute; followed by treatment with fungicide Ridomil and Cercobin 0,25% each, then being left to germinate in a BOD camera at 30°C under a photoperiod of 12 hours. For evaluating the effect of different water potentials in the germinative process, polyethylene glicol (PEG 6000) was used and the salts NaCI and CaCl 2 used to simulate saline stress. The seeds were put to soak in potentials of 0 (control); -0.1 ; -0.2; -0.3; -0.4 and -0.5MPa. For each treatment 5 repetitions of 20 seeds were used in gerbox, placed between filter paper moistened with 20 mL of PEG, NaCI and CaCl 2 solutions. The solutions were changed at intervals of 24 hours for maintenance of the potential. The evaluations of percentages and germination speed were carry out daily for 8 days, being considered germinated the seeds that presented a 2mm root extension or longer. The data were submitted to analysis of variance and averages compared by the Tukey test at 5% probability. It was concluded that osmotic potentials between -0.4 and -0.5MPa inhibited the germination of seeds of Schizolobium amazonicum completely. The osmotic stress caused by CaCl 2, and PEG injured the germination more than did the stress caused by NaCl.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The objective of this study was to identify treatments capable of promoting and standardizing the germination of Murdannia nudiflora (L.) Brenan seeds. The seeds of this weed were submitted to the following treatments: mechanical abrasion with 220-grit sandpaper (20, 30 and 40 frictions); immersion in sulfuric acid (90% for 30 and 40 seconds), followed by washing in running water; immersion in sodium hypochlorite (2.5% for 8 and 12 hours) and lye (5 minutes), followed by five washings in distilled water; immersion in KNO 3 (1% for 24 hours); preheating at 40°C in a humid or dry substrate for 2, 3 and 4 weeks. The statistical design was totally randomized, with four repetitions. The number of germinated seeds was counted every other day. The most favorable treatments were preheating at 40°C in humid substrate for 3 weeks, followed by mechanical abrasion after 40 frictions and immersion in sulfuric acid for 40 seconds.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Brazil is one of the world's richest countries in forest biodiversity. This has a great importance for humanity for sheltering essential scientific potential for the improvement in the quality of living beings. It also contributes to the preservation of natural resources and the environment. Among Brazil's forest species, jenipapo (Genipa americana L.) is commonly found in riparian vegetation. The objective of this work was to quantify the genetic variability of biochemical traits of seeds, as a support for in situ and ex situ conservation of natural populations of G. americana L. Two populations of the species were studied: one from Ilha Solteira, SP region (ISA) and other from Mogi Guaçu, SP (MOG). In the ISA population, seeds were collected from 30 trees, and in the MOG population, from 22 trees. These seeds were analyzed for chemical composition: content of proteins, carbohydrates, lipids and starch. The two populations of G. americana studied had a great genetic variation for these traits. The population ISA had an additive and phenotypic correlation, which was negative and high for starch with lipid; and positive and medium, for lipid with prolamine, as well as for globulin with prolamine. The population MOG presented additive and phenotypic correlations: positive and medium for gluteline with globulin. In these populations, narrow sense heritability estimates of progenies were moderate (0.69 for carbohydrates in the population ISA) to high (0.81 to 0.99 for the other traits in the two populations), indicating that much progress can be expected with selection strategies.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Despite being known to science for quite a long time, the phenomenon of seed dormancy still baffles the scientific community for the multiple complex underlying mechanisms. The current classification systems of seed dormancy attempt to condense all that is known about the phenomenon in an attempt to generate a conceptual database that would enable facilitated interpretation of upcoming information and allow for a better contextuation of research in this field. The present paper is a preliminary overview of the current panorama of concepts and classification systems of seed dormancy that intends to serve as a standpoint for future research in this field.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The availability of water for seeds is closely related to their germination, since hydration is a limiting factor for their metabolic processes. Therefore, in tests carried out in laboratory, substrate must be sufficiently moistened, in order to assure both the embryo growth and seedling formation. This research was carried out to evaluate the influence of different quantities of water, in different substrates, for cabbage (Brassica oleracea var. capitata) seeds germination. The seeds, processed with Thiran 0.1%, were obtained in shops located in Jaboticabal, São Paulo State, Brazil. Germination tests were made in germitest rolled paper towel substrates, between and on draft paper, moistened with quantities of water equivalent to 1.0; 1.5; 2.0; 2.5; 3.0; 3.5; and 4.0 times the dry substrate weight. For each treatment, four repetitions of 50 seeds were used. The seeds were kept in a germinator, at an alternate temperature of 20-30°C, without further addition of water to the substrate. The evaluations were made on the fifth and tenth days after the experiment preparation. The results obtained revealed that the quantities of water ranging from 1.5 to 2.5 times the paper weight were favorable for seeds germination, mainly in the substrate on and between the paper, while water levels above 3.0 times the substrate weight were harmful for cabbage seeds germination in the rolled paper towel substrates and between the paper.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The use of fungicides for treating seeds has become an essential measure in the control of pathogens. However, the effectiveness of many products is not well-known to some crops. The objective of this research was to evaluate the effect of different doses of carbendazin and carboxin + thiram fungicides for controlling pathogens and their interference on the physiologic quality of castor bean seeds. The test consisted of the following treatments (g i.a./100 kg of seeds): carbendazin (15, 30, and 60), carboxin + thiram (25 + 25, 50 + 50, and 100 + 100), formol 0.15% (v/v), and control (distilled water). The physiologic quality of the seeds was determined by germination, first counting, field emergence, speed emergence index, length, fresh and dry weight of the aerial part, and electrical conductivity. There were no statistical differences for germination and fresh and dry matter index. The treatment with formol provided lower values for first counting and field emergence. Seeds treated with fungicides presented higher values for electrical conductivity, but did not differ, statistically, among themselves. The fungi Cladosporium spp.; Bipolaris spp.; Curvularia spp.; Aspergillus flavus; Aspergillus niger; Rhizopus sp.; Penicillium sp.; Rhizoctonia sp.; Verticillium sp.; Fusarium sp.;Arthrobotrys sp.; and Epicocum sp. were identified. All tested products, independently of the dose, provided efficient control for pathogens.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The objective of this study was to evaluate methodologies for the potassium leaching test and to verify its sensitivity for identifying different levels of vigor of arugula seed lots. Five seed lots each of Rucula Cultivada and Rucula Gigante were used. Standard germination, first count of germination, seedling emergence and variations of the potassium leaching test (50 or 100 seeds imbibed in 50 mL or 75 mL in water; at 25 °C and 30 °C; for 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3, 4 and 5 hours) were done. It was observed that the period seeds need to be soaked can be reduced to 2 hours and the water volume can be reduced to 50 mL. The utilization of 50 seeds showed a smaller variation coefficient and the best temperature was 30 °C. It can be concluded that the potassium leaching test for arugula seeds can be run using 50 seeds in 50 mL of water for 2 hours at 30 °C.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Nitrogen limitation in the common bean (Phaseolus vulgaris L.) produces reduced productivity and seeds with low protein content and physiological quality. We assessed the effects of nitrogen fertilizer side dressing on the protein content and physiological quality of the seeds of P. vulgaris L. cultivars (cv.) IPR Juriti and Pérola grown in plots (soil type = Dystrophic Red Latosol) using a no-tillage system under a thick mulch of millet residues at the Experimental Station of UNESP-Ilha Solteira campus, located in Selvíria, MS (Köppen climate type = Aw) during autumn (March/June) and winter (June/September) 2005. For each cultivar, a randomized block experimental design was used with four replicates and factorially arranged treatments equivalent to 0, 30, 60, 90 and 120 kg.ha-1 added nitrogen (as urea, containing 45% of N) applied as a side dressing during the V4-3 and V4-6 phenological stage corresponding to the 3rd and 6th completely opened trifoliolate leaf on the main stem. Supplementation with up to 120 kg.ha-1 nitrogen promoted a greater increase in crude protein at V4-3 (unsupplemented = 17.6% and 16.3%; 120 kg.ha-1 N = 24.1% and 22.3% for cv. IPR Juriti and Pérola, respectively) than at V4-6 (unsupplemented = 19.2% and 18.3%; 120 kg.ha-1 N = 21.3% and 20.3% for cv. IPR Juriti and Pérola, respectively). About 90% of the crude protein from cv. IPR Juriti was composed of soluble protein compared to 72% for the cv. Pérola. Albumins and globulins represented about 80% of the soluble protein and prolamins were lower at 0.6%. In conclusion, nitrogen fertilization up to 120 kg.ha-1 applied as a side dressing at the V4-3 phenological stage in no-tillage under a thick mulch of millet promoted a greater increase of crude protein in common bean seeds than at the V4-6 stage. The highest accumulation of soluble protein occurred at 90 kg.ha-1 applied nitrogen without having a significant influence on the physiological quality of the seeds.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The speed and magnitude of tropical pastures expansion in Brazil are related to the availability of quality seeds. This research aimed to evaluate the physiological quality of seeds of two Brachiaria species submitted to germination and viability tests and also estimate, for both species, the fresh and dry mass yield, under different irrigated crop-livestock integration systems. For field analysis, the experimental design was a randomized complete block, in subplots, with four intercrops in the plot (Brachiaria brizantha cv. Marandu and Brachiaria ruziziensis simultaneously established with corn and nitrogen fertilization coverage), and four forage cutting times, in the winter/spring season, in subplots, with four replications. In the laboratory, the experimental design was completely randomized, with four replications per treatment/test. The germination and viability tests indicated that B. brizantha seeds showed higher physiological quality, when compared with B. ruziziensis, while the tetrazolium test and germinated seedlings characteristics were similar. The B. ruziziensis, simultaneously intercropped with corn, was the less viable intercrop, due to the lower fresh and dry mass yield and litter deposition on the soil surface. In general, the pasture formation for the second season cultivation, intercropped with corn, was an excellent alternative for crop-livestock integration under a no-tillage system.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The objective of this work was to characterize external and internal morphologic aspects of the fruit, seed, and plant of Moringa oleifera Lam. The fruits were collected in the forest garden of Falculty of Agrarian and Veterinarian Sciences, São Paulo State University, Jaboticabal-SP, Brazil. It was observed that the Moringa fruits are brown simple darkness, dry of the type capsule, tends on average: 28.50 cm of length, 2.21 cm of width, 9.91 g of mass and with 12 seeds by fruit, it considerated fruits of medium and small size. The seeds are brown dark and they present three lines clear chestnut tree. The embryo is oleaginous, has a pair of cotyledons and the germination is hypogeal-cryptocotyledonary. The seed has1.037 cm of length and 1.0 cm of thickness of average and have a considerate medium and light weight (197g/1000 seeds). The germination began eight days after the planting and in the 25th day they left the primary leaves.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study aimed to evaluate the effect of aqueous extract of neem on germination and fungi incidence on seeds of three cultivars (Serrinha, BR 17 and Maranhão) of cowpea. Neem leaves were dryed, crushed and prepared dilutions of 0.5; 1.0; 2.0, 4.0 g dm -3and control. The fungi incidence was evaluated by the test filter paper and germination according to the Rules for Seeds Testing (Regras para Análise de Sementes). In the three cultivars analyzed, reduction in the incidence of Aspergillus sp and Fusarium sp was observed. In relation to the influence of extracts of neem leaves on seed germination, significant effect of extract in Maranhão cultivar was observed, where all concentrations differed from the control, and propovided a considerable increase in the percentage of normal seedlings. It was concluded that the leaf extract of neem was effective in controlling Aspergillus sp, Fusarium sp , Phoma sp and Macrophomina phaseolina at different concentrations in different cultivars and seed germination was stimulated for the Maranhão cultivar.