Envelhecimento acelerado em sementes de Eucalyptus grandis Hill ex Maiden classificadas por tamanho

Two experiments of seed ageing of Eucalyptus grandis Hill ex Maiden were carried out at laboratory conditions. In the first experiment, two seed lots were classified in two square mesh screens (< 0.84 to ≥ 0.71 mm and < 0.71 mm to ≥ 0.59 mm), submitted to 42 °C and 100% relative humidity, for 0, 8, 12, 24, and 32 hours of stress treatments. Seed germination tests were done with just aged seeds. The results showed that the stress period was not sufficient for ageing the seeds. In the second experiment, the best quality seed lot was separated in the same two sizes. The seeds were submitted under the same stress conditions of the first experiment but for 0, 48, 72, and 96 hours. The germination test was done right after the seeds were taken from the stress conditions, and with stored seeds at dry chamber (2 weeks and 26 months). It was concluded that both seed sizes reached 30% of moisture content under 72 hours of ageing conditions and showed significant germination losses when compared with seeds without ageing (control), as the moist seeds as the stored ones at dry chamber, for both 2 weeks and 26 months.

Testes de vigor para avaliação da qualidade fisiológica de sementesde Sebastiania commersoniana (Baill.) Smith & Downs.

The objective of this work was to evaluate the efficiency of different vigor tests to assess S. commersoniana seeds physiological quality during storage. Therefore, seeds were stored in cloth bags, plastic bags and glass containers for 531 days, both at room temperature and in a cold chamber. Periodically samples were taken and the following tests were conducted: standard germination, germination speed index, first count after germination, seedlings fresh and dry matter, electrical conductivity (imbibitions for 2 and 24 hours) and accelerated aging, in order to monitoring the seeds physiologic quality. Data were submitted to polynomial regression analysis, for each of the combination of packaging/storage condition. The results obtained led to the following considerations: a) the speed germination index and the accelerated aging test permitted a good evaluation of the seed-lots quality; b) the first count of germination did not allow any prediction about seed lots vigor; c) seedling fresh and dry matter did not discriminate among seed lots; d) electrical conductivity test after 2 h imbibitions was not adequate to evaluate the seed lots vigor and e) the electric conductivity test with 24 h imbibitions was more adequate to differentiate among seed lots, but with little efficiency to discriminate among seed lots with intermediate vigor or with low quality differences.

The fat body of termites: Functions and stored materials

The functions of the fat body in the different castes of termites, and accumulation of energy reserves, proteins and urates within this organ, are reviewed. The termite fat body is involved in multiple metabolic activities, including recycling of nitrogen. Termite fat body showed three different types of cells: adipocytes, urocytes and mycetocytes, the latter restricted to the species Mastotermes darwiniensis. Adipocytes synthesize and store lipids, glycogen and several proteins. These cells also elaborate important peptides, including some that act in immune processes. Urocytes are responsible for the storage of spherocrystals of urates, which vary quantitatively among the termite castes. The different metabolic functions of the fat body in the several castes and stages of termites are associated with specific adipocyte morphologies. The synthesis and storage of different compounds modify the structure of the fat body; this differentiation is coordinated by hormones involved with molting and reproductive cycles. © 2013 Elsevier Ltd.

Qualidade de sementes de crambe submetidas a métodos de secagem e períodos de armazenamento

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Teste de condutividade elétrica para sementes de milho e de soja armazenadas sob baixa temperatura

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Armazenamento das sementes associado a embebição, hormônios e 'KNO IND. 3' na germinação e desenvolvimento inicial de mudas de Passiflora alata Dryander

Pós-graduação em Agronomia - FEIS

Ação antioxidante da água catódica: estudos preliminares em sementes de café

Coffee seeds have limitations regarding to its conservation because of their sensitivity to desiccation and storage behavior. The establishment of a methodology for seed storage is difficult due to its deterioration. Deterioration can enhance the production of reactive oxygen species and cause lethal oxidative damage to plant tissues. The damage caused by harmful levels of free radicals can be softened by the action of endogenous or exogenous antioxidants. Recent research shows new antioxidative protection technologies, being cathodic protection a promising technique with relevant results in other recalcitrant species and even in other living organisms. Thus, the aim of this work was to verify the antioxidant effect of cathodic water in Coffea arabica L. seeds with the purpose of investigating a new technology to improve seed quality. The study was conducted at the Central Seed Laboratory, Department of Agriculture, at the Federal University of Lavras. Coffea arabica L. seeds were used. The study was conducted in two stages, in the first a preliminary analysis of the use of cathodic water was carried out in batches with different levels of quality. In the second it was evaluated the effect of light and of the imbibition period of the seeds in cathodic water. The seeds were immersed in distilled water and in cathodic water for eight distinct soaking periods, in absence and presence of light and then evaluated by physiological tests. It can be concluded that cathodic water can positively influence the physiological performance of the coffee seeds with poor quality, especially when embedded during periods between 4.5 to 7.5 hours in the absence of light.

Armazenamento de sementes pré-germinadas de Inga vera Willd

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

Conservação de sementes de taperebá (Spondias mombin L., Anacardiaceae)

Pós-graduação em Agronomia (Agricultura) - FCA

Efeito do ácido sulfúrico concentrado sobre o potencial fisiológico de sementes de Brachiaria brizantha (A. Rich.) Stapf cv. 'Marandu' e Brachiara humidicola (Rendle) Schweick cv. 'Tully' durante o armazenamento

Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

Estudos de alguns aspectos de germinação e bioquímicos de sementes de Bauhinia cheilantha (Bong.) Steud., sob diferentes condições de armazenamento

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Germinação e aspectos morfológicos de sementes de Dypsis leptocheilos (Hodel) Beentje & J. Dransf. (Arecaceae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Alterações histológicas e bioquímicas e potencial fisiológico de sementes de soja

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Germinação e aspectos morfológicos de sementes de Archontophoenix cunninghamii H. Wendl. & Drude (Arecaceae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Bases fisiológicas para a conservação a longo prazo de sementes Cariniana legalis (Mart.) O. Kuntze

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)