Morfoanatomia e ontogênese de Machaerium Pers. (Fabaceae: Faboideae): fruto, semente e plântula

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estrututra e ontogênese de órgãos reprodutivos de Connarus suberosus Planch. (Connaraceae) e Oxalis cytisoides Cucc. (Oxalidaceae)

Pós-graduação em Ciências Biológicas (Botânica) - IBB

Leaf anatomical features of three Theobroma species (Malvaceae s.l.) native to the Brazilian Amazon

As espécies de Theobroma têm importância econômica devido a sua utilização nas indústrias cosmética e alimentícia, principalmente na produção de chocolate. Entretanto, a anatomia de suas estruturas vegetativas permanece pouco conhecida. O presente estudo teve por objetivo descrever as características anatômicas de Theobroma grandiflorum, T. speciosum e T. subincanum, como contribuição ao conhecimento biológico dessas espécies, bem como, fornecer subsídios aos estudos biotecnológicos de fruteiras nativas da Amazônia. Folhas em diferentes estágios de desenvolvimento foram coletadas e analisadas sob microscopia de luz e eletrônica de varredura. Nas folhas expandidas de T. grandiflorum e T. subincanum foram observados tricomas dos tipos estrelado séssil, pedunculado e glandular digitiforme. Estas espécies também foram similares quanto à morfologia da nervura central, à organização do mesofilo e à presença de grãos de amido no parênquima medular da nervura central. Tricomas glandulares claviformes e células mucilaginosas na epiderme do limbo foliar ocorreram somente em T. speciosum. A presença de tricomas secretores de mucilagem nos ápices vegetativos (coléteres) de todas as espécies estudadas é um novo registro para o gênero Theobroma.

Análise cinemática das articulações dos membros torácicos e pélvicos de ovinos hígidos

Pós-graduação em Ciências Biológicas (Botânica) - IBB

Trichome structure and evolution in Neotropical lianas

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

What do floral anatomy and micromorphology tell us about Neotropical Bulbophyllum section Didactyle (Orchidaceae: Bulbophyllinae)?

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

Anatomia floral de espécies de Bulbophyllum sect. Micranthae (Orchidaceae, Asparagales)

Bulbophyllum, which comprises 1876 species, is considered the second largest genus of angiosperms, with a pantropical distribution. The morphological and anatomical floral studies in the genus are incipient, with data restricted to the gynostemium and lip of some species. Based on molecular data, six sections were recognized within Bulbophyllum at the Neotropics, amongst them Bulbophyllum sect. Micranthae, which comprises 12 species distributed in central South America. We aimed to study the floral anatomy of six species of Bulbophyllum sect. Micranthae, in order to determine useful characters to differentiate them and contribute to the anatomical characterization of the section as a whole. Floral anatomy was assessed through usual techniques of light microscopy. The data found here for B. adiamantinum, B. chloroglossum, B. epiphytum, B. mentosum, B. micranthum and B. rupicolum allowed to identificate the presence of glandular trichomes and the possible presence of a secretory region on the lip, which might produce substances used as a reward to pollinators. The most significant anatomical characters to the species characterization were the shape and ornamentation of the outer periclinal walls of the epidermal cells, as well as the number of vascular bundles in dorsal and lateral sepals and at the lip. The data also allowed the differentiation between B. epiphytum and B. rupicolum, species very similar in morphology and phylogenetically related. Besides that, the data also allowed the discussion regarding the maintenance of B. mentosum within the section: although its inclusion is supported by molecular studies, the anatomical data here presented shows greater differences compared to the other species, not supporting its maintenance in Bulbophyllum sect. Micranthae

Micromorfologia e anatomia floral das seções neotropicais de Bulbophyllum Thouars (Orchidaceae, Asparagales): considerações taxonômicas e evolutivas

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

Comparative floral micromorphology and anatomy of species of Bulbophyllum section Napelli (Orchidaceae), a Neotropical section widely distributed in forest habitats

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

Anatomy of extrafloral nectaries in Fabaceae from dry-seasonal forest in Brazil

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

Produtividade e perfil químico de óleo essencial de acessos de Varronia curassavica Jacq. em diferentes horários de coleta e período sazonal

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evolution of extrafloral nectaries: adaptive process and selective regime changes from forest to savanna

Much effort has been devoted to understanding the function of extrafloral nectaries (EFNs) for antplantherbivore interactions. However, the pattern of evolution of such structures throughout the history of plant lineages remains unexplored. In this study, we used empirical knowledge on plant defences mediated by ants as a theoretical framework to test specific hypotheses about the adaptive role of EFNs during plant evolution. Emphasis was given to different processes (neutral or adaptive) and factors (habitat change and trade-offs with new trichomes) that may have affected the evolution of antplant associations. We measured seven EFN quantitative traits in all 105 species included in a well-supported phylogeny of the tribe Bignonieae (Bignoniaceae) and collected field data on antEFN interactions in 32 species. We identified a positive association between ant visitation (a surrogate of ant guarding) and the abundance of EFNs in vegetative plant parts and rejected the hypothesis of phylogenetic conservatism of EFNs, with most traits presenting K-values < 1. Modelling the evolution of EFN traits using maximum likelihood approaches further suggested adaptive evolution, with static-optimum models showing a better fit than purely drift models. In addition, the abundance of EFNs was associated with habitat shifts (with a decrease in the abundance of EFNs from forest to savannas), and a potential trade-off was detected between the abundance of EFNs and estipitate glandular trichomes (i.e. trichomes with sticky secretion). These evolutionary associations suggest divergent selection between species as well as explains K-values < 1. Experimental studies with multiple lineages of forest and savanna taxa may improve our understanding of the role of nectaries in plants. Overall, our results suggest that the evolution of EFNs was likely associated with the adaptive process which probably played an important role in the diversification of this plant group.

Anatomy and essential oils from aerial organs in three species of Aldama (Asteraceae-Heliantheae) that have a difficult delimitation

Recently, molecular analysis caused the South American Viguiera Kunth species to be transferred to Aldama La Llave. However, the circumscription has not been established for certain of the South American species, including Aldama filifolia (Sch. Bip. ex Baker) E. E. Schill. & Panero, A. linearifolia (Chodat) E. E. Schill. & Panero and A. trichophylla (Dusen) Magenta (comb. nov.), which had previously been treated as synonyms because of their high similarity. Therefore, the present study aimed to evaluate the anatomy of the aerial organs, and the yield and chemical composition of the essential oils from these three species, to determine the differences among them and thereby assist in species distinction. The anatomical analysis identified characteristics unique to each species, which are primarily related to the position and occurrence of secretory structures. Histochemical analysis demonstrated that the glandular trichomes and the canals secrete lipophilic substances, which are characterised by the presence of essential oils. The analysis of these essential oils identified monoterpenes as their major constituent and allowed for the recognition of chemical markers for each species. The anatomical and chemical characteristics identified by the present study confirmed that the studied samples belong to three distinct taxa.

Microbial transformation of the sesquiterpene lactone tagitinin C by the fungus Aspergillus terreus

The biotransformation of the sesquiterpene lactone tagitinin C by the fungus Aspergillus terreus MT 5.3 yielded a rare derivative that was elucidated by spectrometric methods. The fungus led to the formation of a different product through an unusual epoxidation reaction between C4 and C5, formation of a C3,C10 ether bridge, and a methoxylation of the C1 of tagitinin C. The chemical structure of the product, namely 1 beta-methoxy-3 alpha-hydroxy-3,10 beta-4,5 alpha-diepoxy-8 beta-isobutyroyloxygermacr-11(13)-en-6 alpha,12-olide, is the same as that of a derivative that was recently isolated from the flowers of a Brazilian population of Mexican sunflower (Tithonia diversifolia), which is the source of the substrate tagitinin C. The in vitro cytotoxic activity of the substrate and the biotransformed product were evaluated in HL-60 cells using an MTT assay, and both compounds were found to be cytotoxic. We show that soil fungi may be useful in the biotransformation of sesquiterpene lactones, thereby leading to unusual changes in their chemical structures that may preserve or alter their biological activities, and may also mimic plant biosynthetic pathways for production of secondary metabolites.

Isopentenyl diphosphate biosynthesis via a mevalonate-independent pathway: Isopentenyl monophosphate kinase catalyzes the terminal enzymatic step

In plants, the biosynthesis of isopentenyl diphosphate, the central precursor of all isoprenoids, proceeds via two separate pathways. The cytosolic compartment harbors the mevalonate pathway, whereas the newly discovered deoxyxylulose 5-phosphate pathway, which also operates in certain eubacteria, including Escherichia coli, is localized to plastids. Only the first two steps of the plastidial pathway, which involve the condensation of pyruvate and glyceraldehyde 3-phosphate to deoxyxylulose 5-phosphate followed by intramolecular rearrangement and reduction to 2-C-methylerythritol 4-phosphate, have been established. Here we report the cloning from peppermint (Mentha × piperita) and E. coli, and expression, of a kinase that catalyzes the phosphorylation of isopentenyl monophosphate as the last step of this biosynthetic sequence to isopentenyl diphosphate. The plant gene defines an ORF of 1,218 bp that, when the proposed plastidial targeting sequence is excluded, corresponds to ≈308 aa with a mature size of ≈33 kDa. The E. coli gene (ychB), which is located at 27.2 min of the chromosomal map, consists of 852 nt, encoding a deduced enzyme of 283 aa with a size of 31 kDa. These enzymes represent a conserved class of the GHMP family of kinases, which includes galactokinase, homoserine kinase, mevalonate kinase, and phosphomevalonate kinase, with homologues in plants and several eubacteria. Besides the preferred substrate isopentenyl monophosphate, the recombinant peppermint and E. coli kinases also phosphorylate isopentenol, and, much less efficiently, dimethylallyl alcohol, but dimethylallyl monophosphate does not serve as a substrate. Incubation of secretory cells isolated from peppermint glandular trichomes with isopentenyl monophosphate resulted in the rapid production of monoterpenes and sesquiterpenes, confirming that isopentenyl monophosphate is the physiologically relevant, terminal intermediate of the deoxyxylulose 5-phosphate pathway.