Anatomical traits and structural components of peduncle associated with lodging in Avena sativa L.

Received: May 14th, 2020 ; Accepted: June 19th, 2020 ; Published: January 5th, 2021 ; Correspondence: [email protected] dramatically reduces the yield of cereals and increases the difficulty of mechanical harvesting. Because it is a complex phenomenon, new cultivars with genetic resistance to lodging is a sustainable alternative in agricultural production systems. This resistance is associated with a combination of factors, such as stem thickness and stiffness, being closely linked to anatomical traits and structural carbohydrates present in the stem. In the present study we compared, under field conditions, eight contrasting oat cultivars in terms of lodging resistance. Our aim in this study was to investigate the association of anatomical traits and structural components of the peduncle with resistance to lodging, aiming to assist in the plant selection process. In addition, a second objective was to understand the genetic dissimilarity among oat cultivars according to the characters studied. Some characteristics for potential indirect selection were studied in this work and if correlated with lodging can be used to identify superior genotypes. From the anatomical point of view, the correlation obtained between the internal vascular bundle and the lodging resistance factor allowed us to confirm that this trait can be used in indirect selection to lodging resistance. The structural components of peduncle, in the two ways explored in the present study, comparison of mean and correlation, did not demonstrate the potential to be used exclusively as plant selection characters traits for lodging resistance. There is noticeable variability in oat cultivars for most stem traits

Floristic composition and community structure of epiphytic angiosperms in a terra firme forest in central Amazonia

This survey aimed to describe the floristic composition and structure of the epiphytic community occurring in a terra firme forest in the city of Coari, Brazil, in the Amazon region. Data collection was performed with a 1.5 ha plot method, with which upland, slope and lowland habitats were sampled. All angiosperm epiphytes and their host plants (diameter at breast height > 10 cm) were sampled. We recorded 3.528 individuals in 13 families, 48 genera and 164 species. Araceae was the most prevalent family with regard to the importance value and stood out in all related parameters, followed by Bromeliaceae, Cyclanthaceae and Orchidaceae. The species with the highest epiphytic importance values were Guzmania lingulata (L.) Mez. and Philodendron linnaei Kunth. The predominant life form was hemiepiphytic. Estimated floristic diversity was 3.2 (H'). The studied epiphytic community was distributed among 727 host plants belonging to 40 families, 123 genera and 324 species. One individual of Guarea convergens T.D. Penn. was the host with the highest richness and abundance of epiphytes. Stems/trunks of host plants were the most colonized segments, and the most favorable habitat for epiphytism was the lowlands, where 84.1% of species and 48.2% of epiphytic specimens were observed

Diversidade de bromeliáceas epífitas na Área de Proteção Ambiental Ilha do Combu, Belém, Pará, Brasil Diversity of epiphytic bromeliads in the environmental protection area of Combu Island, Belém, Pará, Brazil

Informações sobre a diversidade no nível de espécie oferecem subsídios importantes para o desenvolvimento sustentável e a conservação biológica. Neste contexto, estudos com Bromeliaceae merecem destaque, especialmente porque o grupo é importante ecologicamente, mas ainda pouco conhecido na Região Norte. Neste trabalho, foram demarcadas duas parcelas de 100 m x 100 m em uma floresta de várzea localizada na Área de Proteção Ambiental Ilha do Combu, em Belém, Estado do Pará. Cada parcela foi subdividida em oito parcelas de 50 m x 50 m, tendo todas as espécies e espécimes de bromeliáceas epífitas registradas e quantificadas. A diversidade do grupo foi calculada utilizando o índice de Shannon-Wiener. Foram registrados 1.339 indivíduos pertencentes a oito espécies e quatro gêneros. Tillandsia e Aechmea apresentaram maior riqueza. A diversidade de espécies na área foi de H= 1,10, apresentando dominância acentuada de muitos indivíduos em poucas espécies.<br>Information about diversity at the species level offers data for sustainable development and biological conservation. In this context, studies about Bromeliaceae are noteworthy, especially because this group is ecologically important and poorly known in the North Region of Brazil. In this study, two grids (100 m x 100 m) were delineated in a floodplain forest in the environmental protection area of Combu Island, Belém, Pará, Brazil. The grids were subdivided into eight grids of 50 m x 50 m, and all species and individuals of epiphytic Bromeliaceae were recorded and quantified. The diversity was calculated using the Shannon-Wiener index. A total of 1,339 individuals, belonging to eight species and four genera were recorded. Tillandsia and Aechmea presented the greatest richness. The diversity of species was H= 1.10, presenting sharp dominance of many individuals of few species

Orchidaceae das Serras Negra e do Funil, Rio Preto, Minas Gerais, e similaridade florística entre formações campestres e florestais do Brasil

Neste estudo, foi realizado o levantamento das Orchidaceae das Serras Negra e do Funil (SN/SF), Zona da Mata de Minas Gerais, e uma análise da similaridade florística dessa família entre 29 áreas campestres e florestais do Brasil. Para tal análise, utilizou-se o algoritmo UPGMA, coeficiente de SØrensen, e 5.000 replicações de bootstrap. A análise de agrupamento revelou baixos índices de similaridade, exceto para os grupos Serra Negra + Parque Estadual do Ibitipoca e Parque Estadual da Ilha do Cardoso + Estação Ecológica Juréia-Itatins. Os resultados sugerem que a região das SN/SF represente um corredor florístico entre localidades na Serra da Mantiqueira (Parque Nacional do Itatiaia) e Serra do Mar (Reserva Biológica de Macaé de Cima). Foi observado o agrupamento de áreas com semelhanças ambientais e as regiões de campos rupestres se destacaram em termos de particularidades florísticas. O teste de Mantel revelou que a similaridade florística não está correlacionada à distância geográfica entre as áreas.This study presents a survey of the Orchidaceae from Serra Negra and Serra do Funil (SN/SF), 'Zona da Mata', Minas Gerais state, and analyzes the floristic similarity of this family among 29 grassland and forest sites in Brazil. Cluster analysis used the UPGMA algorithm, SØrensen coefficient, and bootstrap analyses with 5,000 replications. The cluster analyses revealed low similarity indices; exceptions are the clusters composed of Serra Negra + Ibitipoca State Park and Ilha do Cardoso State Park + Juréia-Itatins Ecological Station. The results suggest that SN/SF represents a floristic corridor between sites in Serra da Mantiqueira (Itatiaia National Park) and Serra do Mar (Macaé de Cima Biological Reserve). Groups of areas with similar environmental conditions were observed and the "campos rupestres" regions stood out because of their singular floristic composition. The Mantel test revealed that floristic similarity is not associated with geographic distance between the areas