Métodos de remoção da mucilagem e qualidade fisiológica de sementes de tomate (Lycopersicon esculentum, Mill.)

Objetivando estudar diferentes métodos de remoção da mucilagem e a qualidade de sementes de tomate (Lycopersicon esculentum Mill.), conduziu-se um experimento, em delineamento inteiramente casualizado com quatro repetições. Após extração manual, sementes e mucilagens foram submetidas aos seguintes tratamentos de remoção: lavagem imediata, fermentação por três dias, ácido clorídrico a 2,5% (25 ml/kg, durante 2 horas), ácido acético a 10% (25 ml/kg de material) e hidróxido de amônia a 2,5% (25 ml/kg, durante 2 horas). Seguiu-se a avaliação da qualidade fisiológica das sementes através das determinações de porcentagem de germinação e vigor, pela porcentagem de emergência em areia, condutividade elétrica e pesos das matérias verde e seca de plântulas. Os resultados permitiram concluir que os métodos de remoção por lavagem imediata, fermentação, ácido clorídrico e ácido acético comercial não afetaram a qualidade fisiológica de sementes de tomate; a porcentagem de germinação não foi afetada pelos diferentes métodos de remoção e o método hidróxido de amônia prejudica o vigor das sementes.

Disponibilidade hídrica e germinação de sementes de cebola (Allium cepa L.)

Objetivando verificar a influência do teor de água do substrato na germinação de sementes de cebola (Allium cepa L.), conduziu-se um ensaio sob condições de ambiente de laboratório. Os efeitos de cinco níveis de água no substrato solo x areia (3:1), 20, 40, 60, 80 e 100% da capacidade de retenção foram avaliados através da porcentagem de emergência no 14° dia da semeadura e pesos da matéria verde e seca das plântulas normais. Para tanto, 200 sementes do cultivar Pira Ouro por tratamento, em quatro repetições de 50, foram semeadas a 1,5 cm de profundidade, mantendo-se constantes os níveis de água no substrato. Os resultados possibilitaram concluir que os níveis de umidade do solo indicados para germinação de sementes de cebola são de 40% e 60% da capacidade de retenção do substrato, por possibilitarem uma melhor emergência, peso da matéria verde e seca das plântulas.

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.

Qualidade fisiológica de sementes de diferentes árvores matrizes de Corymbia citriodora (Hook.) K.D.Hill & L.A.S. Johnson

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of Hot Air Drying on Ultrastructure of Crambe Seeds

This study was conducted to evaluate the morphologic modifications in tissues of the fruit and seed of the crambe (Crambe abyssinica Hochst. Ex R.E. Fr.) after drying at different temperatures. Fruits with a water content of 0.38 kg water/kg dry matter were harvested and manually homogenized. Drying was accomplished at 35, 45, 60, 75, and 90°C and at 21,9,7,5, and 2% relative humidity, respectively. After drying, the structure of the pericarp and tegument of the seed were evaluated and the embryo was removed from the fruit/seed for morphological analysis (structural and ultrastructural and the histolocalization of reserve substances). Drying at different temperatures did not affect the cellular structure of the tissues composing the pericarp of the fruits, but it disorganized the structure of the seed tegument. The cells of the tegument and cotyledons presented a contraction in their volumes. The lowest contractions in the cellular volumes of both the tegument and cotyledons occurred after drying at 35 and 45°C. The cytoplasm of the cotyledon cells contains oil drops and the protein bodies contain protein granules and starch grains. There were no changes in the cellular walls of the embryos of the fruits dried at different temperatures; however, ungluing of the medium lamella occurred. This damage occurred with greater intensity after drying at temperatures above 60°C. The form of the oil drops in the cytoplasm of the cotyledon cells was altered after drying. At temperatures above 60°C, the drops broke up and coalesced. After drying at 45 and 60°C, the form of some protein bodies was altered, whereas at 75 and 90°C coalescence of the protein bodies occurred in some cells. It was concluded that the identified alterations can affect the physiologic quality of crambe seeds. © 2013 Copyright Taylor and Francis Group, LLC.

Glicerina, resíduo da produção de biodiesel, na terminação de novilhas da raça Nelore

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito do manejo alimentar nos Parâmetros nutricionais e comportamento ingestivo em cabras leiteiras

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Size matters: plasticity in metabolic scaling shows body-size may modulate responses to climate change

Variability in metabolic scaling in animals, the relationship between metabolic rate ( R) and body mass ( M), has been a source of debate and controversy for decades. R is proportional to Mb, the precise value of b much debated, but historically considered equal in all organisms. Recent metabolic theory, however, predicts b to vary among species with ecology and metabolic level, and may also vary within species under different abiotic conditions. Under climate change, most species will experience increased temperatures, and marine organisms will experience the additional stressor of decreased seawater pH ('ocean acidification'). Responses to these environmental changes are modulated by myriad species-specific factors. Body-size is a fundamental biological parameter, but its modulating role is relatively unexplored. Here, we show that changes to metabolic scaling reveal asymmetric responses to stressors across body-size ranges; b is systematically decreased under increasing temperature in three grazing molluscs, indicating smaller individuals were more responsive to warming. Larger individuals were, however, more responsive to reduced seawater pH in low temperatures. These alterations to the allometry of metabolism highlight abiotic control of metabolic scaling, and indicate that responses to climate warming and ocean acidification may be modulated by body-size.

Effects of plant functional traits on soil stability: intraspecific variability matters

This data set describes different vegetation, soil and plant functional traits (PFTs) of 15 plant species in 30 sampling plots of an agricultural landscape in the Haean-myun catchment in South Korea. We divided the data set into two main tables, the first one includes the PFTs data of the 15 studied plant species, and the second one includes the soil and vegetation characteristics of the 30 sampling plots. For a total of 150 individuals, we measures the maximum plant height (cm) and leaf size (cm**2), which means the leaf surface area for the aboveground compartment of each individual. For the belowground compartment, we measured root horizontal width, which is the maximum horizontal spread of the root, rooting length, which is the maximum rooting depth, root diameter, which is the average root diameter of a the whole root, specific root length (SRL), which is the root length divided by the root dry mass, and root/shoot ratio, which is the root dry mass divided by the shoot dry mass. At each of the 30 studied plots, we estimated three different variables describing the vegetation characteristics: vegetation cover (i.e. the percentage of ground covered by vegetation), species richness (i.e. the number of observed species) and root density (estimated using a 30 cm x 30 cm metallic frame divided into nine 10 cm x 10 cm grids placed on the soil profile), as we calculated the total number of roots that appear in each of the nine grids and then we converted it into percentage based on the root count, following. Moreover, in each plot we estimated six different soil variables: Bulk density (g/cm**3), clay % (i.e. percentage of clay), silt % (i.e. percentage of silt), soil aggregate stability, using mean weight diameter (MWD), penetration resistance (kg/cm**2), using pocket penetrometer and soil shear vane strength (kPa).

Critical matters

This year, as it has been during most of the years that I can remember, AILA's various state awards have been controversial (depending on who you talk to). In at least one state, after only a small number of awards have been handed out, the local chapter is thinking of modifying the awards to (presumably) bring them into synch with the values of local member practices. In almost every case when an awards-related complaint has been made, the judges have been seen as the problem. After all, the judges make the determination so they must have poor judgement.