Protein expression upon desiccation and imbibition of Magnolia ovata A. St.-Hil seeds

The effect of seed drying and imbibition was studied by differential protein expression using two dimensional gel electrophoresis. After drying to a range of water contents, seeds were germinated to assess the viability. Seeds of Magnolia ovata did not withstand the desiccation down to 0.10 g H2O · g-1 dw. The critical water content below which the desiccation sensitivity became apparent was around 0.18 g H2O · g-1 dw (-26.5 MPa). Total protein was extracted and separated by 2D electrophoresis from fresh seeds (0.28 g H2O · g-1 dw), mild dried seeds (0.25 g H2O · g-1 dw) and seeds at low water content (0.10 g H2O · g-1 dw) before and after imbibition for 10 days. The proteome profile revealed the presence of 588 spots on each silver stained gel, from which 21 showed differential expression, correlated with desiccation and germination, by increased or decreased expression. After MS/MS sequencing, three protein spots produced spectra that matched to a Magnolia salicifolia legumin precursor. Results suggested an involvement of this protein in the events taking place during the drying and subsequent imbibitions of the dried seeds.

Avaliação da qualidade de sementes sucupira-preta (Bowdichia virgilioides Kunth.) pelo teste de raios X / Evaluation of seed quality of black sucupira (Bowdichia virgilioides Kunth. ) by X ray test

Injúrias representam um fator limitante para a viabilidade de sementes e, dependendo da sua intensidade, podem reduzir o seu vigor, produzindo plântulas fracas e, conseqüentemente, mais susceptíveis às condições adversas. Nesta pesquisa, foi verificada a eficiência do teste de raios X na avaliação de danos em sementes de sucupira-preta e sua relação com o teste de germinação. Inicialmente, as sementes foram expostas a diferentes intensidades de radiação por diferentes tempos, sendo, em seguida, as sementes divididas em três categorias, de acordo com as imagens visualizadas nas radiografias: sementes sem danos, com pequenos danos e danos severos. O experimento foi conduzido em esquema fatorial 3x3, correspondendo a três lotes e três categorias de sementes. As variáveis analisadas foram a porcentagem e índice de velocidade de germinação. Pelos resultados foi observado que a intensidade de 30 Kv por 45 segundos permite melhor visualização dos danos nas sementes de sucupira-preta, danos esses que afetam a germinação.

Injuries represent a limitng factor for the seed viability. Depending on their intensity, the injuries might reduce seed vigour, produce weak seedlings. Consequently, they might be more susceptible to adverse conditions. In this research, the efficiency of X ray test was verifie to evaluate damage in seeds of black sucupira and its relation with germination test. Initially, seeds were exposed to different intensities of radiation for different periods. Next, seeds were separated in three categories according to the images obtained in radiographs: seeds without damage, seeds with little damage and seeds with severe damage. The experiment was conducted in factorial system 3x3, corresponding to three lots and three categories of seeds. The variable analyzed were percentage and germination speed index. It was verified that the intensity of 30 Kv per 45 seconds allowed better visualization of damages in seeds of black sucupira. Damages affect wich severely seed germination.

Comportamento de sementes de Copaifera multijuga durante o armazenamento

In this study, the effect of different storage conditions on the behaviour of Copaifera multijuga Hayne seeds was evaluated in order to determine the criterion for its conservation during a long period. Fresh seeds were enclosed in paper bags (permeable packing) or glass bottles (not permeable packing), and stored in laboratory environment (27"C average temperature and 85% relative humidity) and in a cold cabinet (8ºC temperature and 55% relative humidity), during six months. A randomized design was adapted, with a factorial scheme 2 2 3 (packing method, environment, storage duration), with four replications. The quality of the seeds was evaluated bimonthly through the parameters: water content, germination, emergence speed rate and seedling length. The initial percentage of germination was 94% and the water content, 34%. The viability of the seeds was reduced to 75% and 45%, respectively, in permeable and not permeable packing, after two months of storage in the laboratory environment. The permeable packing in the cold cabinet was found to be efficient for the conservation of the seeds of this species, with 85% percentage of germination, after a storage 4 months.

O objetivo deste trabalho foi estudar o comportamento de sementes de Copaifera multijuga Hayne, sob diferentes condições de armazenamento visando estabelecer critérios para a conservação desse material por um maior período de tempo. Sementes frescas foram acondicionadas em saco de papel (embalagem permeável) e vidro (embalagem impermeável), e armazenadas em ambiente de laboratório (temperatura média 27ºC e umidade relativa 85%) e câmara fria (temperatura de 8ºC e umidade relativa 55%) durante seis meses. O delineamento adotado foi o inteiramente casualizado, em esquema fatorial 2x2x3 (embalagem, ambiente, período), com quatro repetições de 25 sementes. A qualidade das sementes foi avaliada bimestralmente, por meio dos parâmetros: teor de água, germinação, índice de velocidade de emergência e comprimento de plântula. A percentagem de germinação inicial das sementes foi 94% e a umidade 34%. Sementes de Copaifera multijuga tiveram sua viabilidade reduzida para 75% e 45%, em embalagem permeável e impermeável, respectivamente, após dois meses de armazenamento em ambiente de laboratório. A embalagem permeável mostrou-se eficiente na conservação de sementes desta espécie quando mantidas em câmara fria, com percentagem de germinação de 85%, por um período de quatro meses.