Plant functional and taxonomic diversity in European grasslands along climatic gradients

Aim: European grassland communities are highly diverse, but patterns and drivers of their continental-scale diversity remain elusive. This study analyses taxonomic and functional richness in European grasslands along continental-scale temperature and precipitation gradients. Location: Europe. Methods: We quantified functional and taxonomic richness of 55,748 vegetation plots. Six plant traits, related to resource acquisition and conservation, were analysed to describe plant community functional composition. Using a null-model approach we derived functional richness effect sizes that indicate higher or lower diversity than expected given the taxonomic richness. We assessed the variation in absolute functional and taxonomic richness and in functional richness effect sizes along gradients of minimum temperature, temperature range, annual precipitation, and precipitation seasonality using a multiple general additive modelling approach. Results: Functional and taxonomic richness was high at intermediate minimum temperatures and wide temperature ranges. Functional and taxonomic richness was low in correspondence with low minimum temperatures or narrow temperature ranges. Functional richness increased and taxonomic richness decreased at higher minimum temperatures and wide annual temperature ranges. Both functional and taxonomic richness decreased with increasing precipitation seasonality and showed a small increase at intermediate annual precipitation. Overall, effect sizes of functional richness were small. However, effect sizes indicated trait divergence at extremely low minimum temperatures and at low annual precipitation with extreme precipitation seasonality. Conclusions: Functional and taxonomic richness of European grassland communities vary considerably over temperature and precipitation gradients. Overall, they follow similar patterns over the climate gradients, except at high minimum temperatures and wide temperature ranges, where functional richness increases and taxonomic richness decreases. This contrasting pattern may trigger new ideas for studies that target specific hypotheses focused on community assembly processes. And though effect sizes were small, they indicate that it may be important to consider climate seasonality in plant diversity studies

Hemoglobinúria paroxística noturna: relato de dois casos Paroxysmal nocturnal hemoglobinuria: two case reports

A Hemoglobina Paroxística Noturna (HPN) é uma doença adquirida da stem cell hematopoética caracterizada por anemia hemolítica crônica, episódios trombóticos, e com freqüência pancitopenia. É uma desordem clonal, causada por mutação somática do gene PIG-A ligado ao cromossomo X, o qual é requisitado para a formação da estrutura da âncora glicosil-fosfatidil-inositol (GPI). A deficiência da GPI ancorada á proteína CD59 explica a hemólise intravascular na PNH, resultando da inabilidade dos eritrócitos inativar a superfície do complemento. Uma imensa relação clínica existe entre HPN e a anemia aplástica (AA). A ausência de GPI ancorada às proteínas é facilmente detectada pelos métodos de citometria de fluxo aplicados aos eritrócitos e leucócitos; os testes de Ham a da sucrose são absolutos. Em algumas vezes o tratamento com corticóides e/ou androgênio é útil. O transplante de medula óssea alogênico é curativo. O objetivo deste artigo é relatar dois casos de HPN com revisão, enfatizando os aspectos fisiopatológicos, clínicos, diagnósticos e tratamento da HPN.<br>Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hematopoietic stem cell disease characterized by chronic hemolytic anemia, thrombotic episodes and often pancytopenia. It is a chronic disorder caused by a somatic mutation of the X-linked gene PIG-A, which is required for formation of the glycosylphosphatidylinositols (GPI) - anchor structure. Deficiency of the GPI-anchored protein CD59 explains intravascular hemolysis in PNH, which results from the inability of erythrocytes to inactivate the surface complement. A very strong clinical relationship exists between aplastic anemia (AA) and PNH. Absence of GPI-anchored proteins is easily detected by flow cytometric methods applied to both erythrocytes and leukocytes; the Ham and sucrose tests are now obsolete. Treatment with glucocorticoids and / or androgen is sometimes helpful. Allogeneic hematopoietic cell transplantation is curative. The aim of this work is to relate two cases of PNH with review emphasizing the pathophysiological, clinical and diagnostic features and therapy for PNH

Characterization of açaí (E. oleracea) fruits and its processing residues

The aim of this work was to study the source of the açaí residue for its possible commercial applications by characterizing the fruit (fresh and dry mass), and performing an anatomic study of the pericarp from which were identified the origin of the anthocyanins, and fatty acids, and fibers; also the vascular system, its fibers constituents and fibrils were characterized. It was concluded that anthocyanins were located on the epiderm and external parenchyma, and that solids retained on the sieve come from the sclerenchyma, and that the fatty acids come from the storage parenchyma. The vascular tissue was formed by the fibers around 20 mm length. The length distribution of the fibrils had a mean length of 580µm

Germinação de sementes e desenvolvimento de protocormos de Epidendrum secundum Jacq. (Orchidaceae) em associação com fungos micorrízicos do gênero Epulorhiza Seed germination and protocorm development of Epidendrum secundum Jacq. (Orchidaceae) in association with Epulorhiza mycorrhizal fungi

Na natureza, as espécies de Orchidaceae estão associadas a fungos micorrízicos. A compreensão da especificidade fungo-planta nessa associação pode auxiliar no desenvolvimento de programas para propagação simbiótica das orquídeas. Fungos micorrízicos Epulorhiza spp. têm sido isolados de Epidendrum secundum Jacq. com maior freqüência. Assim, o objetivo deste trabalho foi avaliar a germinação de sementes e o desenvolvimento de protocormos de E. secundum associados a diferentes isolados de fungos do gênero Epulorhiza. Utilizou-se 16 fungos Epulorhiza spp. isolados de diferentes populações de E. secundum. Após 44 dias, todos os fungos testados induziram a germinação das sementes. Entretanto, observou-se diferença na eficiência desses fungos em promover o desenvolvimento dos protocormos, mesmo entre os fungos que apresentam semelhanças morfológicas. O estágio de desenvolvimento mais avançado dos protocormos e o maior índice de crescimento foram observados quando as sementes foram inoculadas com o isolado M65. Conclui-se que a germinação das sementes e o desenvolvimento dos protocormos de E. secundum dependem do fungo micorrízico e que, apesar da grande freqüência de associação entre essa espécie de orquídea e fungos do gênero Epulorhiza, é importante a seleção de isolados que apresentem maior eficiência simbiótica. Isolados eficientes são úteis na produção de mudas de orquídeas de importância econômica e ornamental e de espécies ameaçadas de extinção.<br>In nature, species of Orchidaceae are always associated with mycorrhizal fungi. The comprehension of fungal-plant specificity in this association can assist with the establishment of programs that focus on symbiotic propagation of orchids. Epulorhiza mycorrhizal fungi have frequently been isolated from Epidendrum secundum Jacq. Thus, the objective of this study was to evaluate the germination of E. secundum seeds and protocorm development associated with different isolates of Epulorhiza spp. Sixteen Epulorhiza fungi obtained from different E. secundum populations were used. After 44 days, all isolates promoted seed germination of this species. However, differences were observed in the efficiency in promoting seed germination and protocorm development, even among the isolates that had morphological similarities. The highest stage of protocorm development and the highest growth indexes were obtained in the presence of isolate M65. The results suggest that seed germination and protocorm development of E. secundum depend on the mycorrhizal fungi and, despite the high frequency of association between this plant and Epulorhiza, it is important to select isolates with high efficiency to establish symbiosis. Efficient isolates are useful for the production of seedlings that have economic and ornamental importance, as well as for endangered orchids

Comportamento fisiológico de sementes de açaí (Euterpe oleracea Mart.) submetidas à desidratação Physiology behavior of Euterpe oleracea seeds submitted to desiccation

O presente trabalho, objetivando verificar os efeitos imediatos da desidratação sobre o comportamento fisiológico das sementes de açaí (Euterpe oleracea Mart.), utilizou lote oriundo de população de 25 progênies de meio-irmãos, pertencente à Coleção de Germoplasma da Embrapa Amazônia Oriental (Belém/PA). Anteriormente à secagem, foi determinado o grau de umidade das sementes e coletado o tratamento que continha o maior grau de umidade (45%). As demais sementes foram submetidas à secagem, em câmara com circulação de ar (30ºC&plusmn;2ºC), visando à obtenção dos demais tratamentos com 39%, 33%, 27%, 22% e 15% de água. O efeito da desidratação sobre a qualidade das sementes foi avaliado através das seguintes determinações: grau de umidade, teste de germinação, índice de velocidade de emergência e emergência de plântulas. Foi verificado que a desidratação até 39% de água não produz efeitos fisiológicos imediatos sobre as sementes de açaí; a partir de 33% de água, a dessecação favorece progressivamente a redução da germinação e, ao atingir 15% de água, a capacidade germinativa foi anulada.<br>The objective of this article was to verify the physiological effects of desiccation of Euterpe oleracea Mart. seeds. Açai palm seeds from twenty five progenies from the germoplasm collection of Embrapa Amazônia Oriental (Belém, State of Pará, Brazil) were used. Before the desiccation, it was determined the moisture content of the lot and it was removed the treatment with the highest moisture content (45%). The other seeds of the lot were submitted to drying in a chamber with air circulation at 30&plusmn;2ºC aiming to reach the treatments at 39%, 33%, 27%, 22% and 15% of water. The effects of dehydration were evaluated by means of the following determinations: moisture content, germination test, speed and emergency of seedlings. It was concluded that the desiccation to 39% moisture content does not affect the physiology of Euterpe oleracea seeds, but the drying around 33% of water reduce the vigour and germination rates. The seeds did not germinate when the moisture content was 15%