In commercial coffee species (Coffea arabica and Coffea canephora), fruit development is a lengthy process, characterized by tissue changes and evolutions. For example, soon after fecundation and up to mid development, the fruit is mainly constituted of the pericarp and perisperm tissue. Thereafter, the perisperm gradually disappears and is progressively replaced by the endosperm (true seed). Initially present in a "liquid" state, the endosperm hardens as it ripens during the maturation phase, as a result of accumulation of storage proteins, sucrose and complex polysaccharides representing the main reserves of the seed. The last step of maturation is characterized by the dehydration of the endosperm and the color change of the pericarp. Important quantitative and qualitative changes accompany fruit growth, highlighting the importance of its study to better understand the final characteristics of coffee beans. Following a description of the coffee fruit tissues, this review presents some data concerning biochemical, enzymatic and gene expression variations observed during the coffee fruit development. The latter will also be analyzed in the light of recent data (electronic expression profiles) arising from the Brazilian Coffee Genome Project. Key words: Coffea spp, bean development, cell cycle, endosperm, EST, gene expression, pericarp, perisperm.Cytology, biochemistry and molecular changes during coffee fruit development: Em espécies comerciais de café (Coffea arabica e Coffea canephora), o desenvolvimento do fruto de café é um processo longo, caracterizado por mudanças e evoluções nos tecidos. Por exemplo, logo após a fecundação e até a metade do desenvolvimento, o fruto é principalmente constituído pelo pericarpo e perisperma. Em seguida, o perisperma gradualmente desaparece e é progressivamente substituído pelo endosperma (semente verdadeira). Inicialmente o endosperma apresenta-se no estado "líquido", o endosperma endurece durante a fase de maturação, como resultado do acúmulo gradual de proteínas de reserva, sacarose e polissacarídeos complexos representando as principais reservas da semente. O último passo da maturação é caracterizado pela desidratação do endosperma e pela mudança de cor do pericarpo. Importantes alterações quantitativas e qualitativas acompanham o crescimento do fruto, ilustrando a importância do seu estudo para melhor compreender as características finais das sementes de café. Seguindo a descrição dos tecidos do fruto de café, esta revisão apresenta alguns dados relativos às variações bioquímicas, enzimáticas e de expressão gênica durante o desenvolvimento do fruto. A expressão de genes será também analisada em função de dados recentes (perfil de expressão eletrônica) oriundos do Projeto Genoma Brasileiro Café. Palavras-chave: Coffea spp, ciclo celular, desenvolvimento da semente, endosperma, EST, expressão gênica, pericarpo, perisperma. INTRODUCTIONThe Coffea genus contains around 100 species (Charrier and Berthaud, 1985). Within these species, C. arabica (Arabica) and C. canephora (Rob...

We studied cell cycle events in embryos of tomato (Lycopersicon esculentum Mill. cv Moneymaker) seeds during imbibition in water and during osmoconditioning ("priming") using both quantitative and cytological analysis of DNA synthesis and ␤-tubulin accumulation. Most embryonic nuclei of dry, untreated control seeds were arrested in the G 1 phase of the cell cycle. This indicated the absence of DNA synthesis (the S-phase), as confirmed by the absence of bromodeoxyuridine incorporation. In addition, ␤-tubulin was not detected on western blots and microtubules were not present. During imbibition in water, DNA synthesis was activated in the radicle tip and then spread toward the cotyledons, resulting in an increase in the number of nuclei in G 2 . Concomitantly, ␤-tubulin accumulated and was assembled into microtubular cytoskeleton networks. Both of these cell cycle events preceded cell expansion and division and subsequent growth of the radicle through the seed coat. The activation of DNA synthesis and the formation of microtubular cytoskeleton networks were also observed throughout the embryo when seeds were osmoconditioned. However, this preactivation of the cell cycle appeared to become arrested in the G 2 phase since no mitosis was observed. The pre-activation of cell cycle events in osmoconditioned seeds appeared to be correlated with enhanced germination performance during re-imbibition in water.

The production of propolis by honeybees results from a selective collection of exudates from various plant species and present many potentialities in the pharmaceutical industry. The objective of this study was to investigate the chemical profile of Brazilian propolis, as well as their in vitro antioxidant and antibacterial activities. Gas chromatography-mass spectrometry was applied for chemical profiling of propolis extracts. Total phenolic compounds were quantified by Folin-Ciocalteu and antioxidant properties were assessed by 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay. Antibacterial activity was assessed against Staphylococcus aureus, Bacillus subtilis, and Micrococcus luteus. Correlation and multivariate statistical analysis were used to identify potential bioactive compounds in the extracts. Twenty-nine metabolites were identified along with 34 other metabolites that were classified into the following classes: triterpenoids (12), acetyltriterpenoids (3), sesquiterpenes (6), steroids (4), and hydrocarbons (9). The antioxidant capacity (IC) ranged from 21.50 to 78.77μg/mL, whereas the content of total phenolic compounds ranged from 31.88 to 204.30mg GAE/g of dry weight. Total phenolic compounds and methyl retinoate showed a positive correlation with the antioxidant capacity, whereas tetradecanal, γ-palmitolactone and ethyl hydrocinnamate showed a negative correlation. Different sets of metabolites are shown to correlate with the antibacterial activity of the extracts, which is largely dependent on the type of microorganism. This innovative approach allowed us to identify likely bioactive compounds in the extracts, although the mechanism(s) underlying antibacterial activity encompass a complex trait, which might involve synergistic effects.

Considerable advances in our understanding of coffee seed physiology have been made in recent years. However, despite intense research efforts, there are many aspects that remain unclear. This paper gives an overview of the current understanding of the more important features concerning coffee seed physiology, and provides information on recent findings on seed development, germination, storage and longevity.

The activation of the cell cycle in embryo root tips of imbibing tomato (Lycopersicon esculentum Mill. cv Lerica) seeds was studied by flow cytometric analyses of the nuclear DNA content and by immunodetection of p-tubulin. With dry seeds, flow cytometric profiles indicated that the majority of the cells were arrested at the C , phase of the cell cycle. In addition, p-tubulin was not detectable on western blots. Upon imbibition of water, the number of cells in C , started to increase after 24 h, and a 55-kD fl-tubulin signal was detected between 24 and 48 h. Two-dimensional immunoblots revealed at least three different p-tubulin isotypes. Thus, p-tubulin accumulation and DNA replication were induced during osmotic priming. These processes, as well as seed germination rate, were enhanced upon subsequent imbibition of water, compared with control seeds that imbibed but were not primed. By contrast, when aged seeds imbibed, DNA replication, P-tubulin accumulation, and germination were delayed. In all cases studied, both DNA replication and p-tubulin accumulation preceded visible germination. We suggest that activation of these cell-cycle-related processes is a prerequisite for tomato seed germination. Furthermore, p-tubulin expression can be used as a parameter for following the initial processes that are activated during seed imbibition.

BackgroundCompared with major crops, growth and development of Ricinus communis is still poorly understood. A better understanding of the biochemical and physiological aspects of germination and seedling growth is crucial for the breeding of high yielding varieties adapted to various growing environments. In this context, we analysed the effect of temperature on growth of young R. communis seedlings and we measured primary and secondary metabolites in roots and cotyledons. Three genotypes, recommended to small family farms as cash crop, were used in this study.ResultsSeedling biomass was strongly affected by the temperature, with the lowest total biomass observed at 20°C. The response in terms of biomass production for the genotype MPA11 was clearly different from the other two genotypes: genotype MPA11 produced heavier seedlings at all temperatures but the root biomass of this genotype decreased with increasing temperature, reaching the lowest value at 35°C. In contrast, root biomass of genotypes MPB01 and IAC80 was not affected by temperature, suggesting that the roots of these genotypes are less sensitive to changes in temperature. In addition, an increasing temperature decreased the root to shoot ratio, which suggests that biomass allocation between below- and above ground parts of the plants was strongly affected by the temperature. Carbohydrate contents were reduced in response to increasing temperature in both roots and cotyledons, whereas amino acids accumulated to higher contents. Our results show that a specific balance between amino acids, carbohydrates and organic acids in the cotyledons and roots seems to be an important trait for faster and more efficient growth of genotype MPA11.ConclusionsAn increase in temperature triggers the mobilization of carbohydrates to support the preferred growth of the aerial parts, at the expense of the roots. A shift in the carbon-nitrogen metabolism towards the accumulation of nitrogen-containing compounds seems to be the main biochemical response to support growth at higher temperatures. The biochemical changes observed in response to the increasing temperature provide leads into understanding plant adaptation to harsh environmental conditions, which will be very helpful in developing strategies for R. communis crop improvement research.

O pinhão-manso (Jatropha curcas L.) é encontrado em quase todas as regiões intertropicais do planeta, sendo adaptável a condições edafoclimáticas da região Nordeste até São Paulo e Paraná. Objetivou-se através do presente trabalho avaliar o comportamento de sementes e mudas de pinhão-manso quando submetidas à condição de estresse salino. Para isso foram conduzidos dois experimentos, sendo o primeiro realizado em condições de laboratório e o segundo em campo. Para o primeiro experimento as sementes de pinhão-manso, dos dois lotes foram submetidas a diferentes concentrações de cloreto de sódio, obtidas da dissolução de cloreto de sódio em água destilada, obtendo as condutividades elétricas de 2, 4, 6, 8, 10, 12, dS.m-1, constituindo os tratamentos. No experimento II as mudas foram obtidas através da semeadura em vaso, e foram utilizados como tratamentos as concentrações 2, 4, e 6 dS.m-1; como controle foi utilizado água destilada para os dois experimento. Sementes de pinhão-manso sofrem atraso no processo germinativo, devido a condições de salinidade. Há redução no crescimento das plântulas quando submetidas à solução de NaCl com condutividade elétrica de 6 dS.m-1. Dessa forma, a condição de estresse salino interfere nos processos fisiológicos das sementes de pinhão-manso.

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