Extrafloral nectaries (EFNs) are found in many species of Fabaceae. The aim of this work is to describe the internal morphology of the EFNs from species of Fabaceae found in areas of dry-seasonal forest in north-eastern Brazil. All species of Fabaceae with EFNs found were collected and samples were submitted to conventional techniques for anatomical and scanning electronic microscopy analysis. EFNs were found in 35 species, of which 32 were examined anatomically. All types have epidermal cells, secretory tissues and vascular bundles in the EFNs. Sclerenchymatous cells were found between the secretory tissues and the vascular tissues, with a few exceptions. The function of these cells is not clear; however, a role in the transportation of the sap in the nectary or with the support of the secretory tissue is possible. The nectar is released through glandular trichomes, secretory pores or even by breaking the epidermal cells and cuticle. The internal patterns found in the EFNs from different species and genera can provide important information for taxonomic and evolutionary studies in the family.
Inselbergs are rocky environments that support a unique flora distinct from that of the surrounding area. The objectives of this work were to conduct a floristic inventory of an inselberg in the semi-arid region of Northeast Brazil, and to investigate the relationship between its flora and the flora of the surrounding area. The following questions were addressed: is the species richness comparable to other inselbergs in northeastern Brazil; is the floristic composition of the inselberg more similar to other inselbergs or to the surrounding Caatinga vegetation; and do the similarities in the floristic composition of inselbergs depend on the distance between them? This work documents 201 species in 62 families. Cyperaceae (28 spp.), Euphorbiaceae (19), Poaceae (15), Orchidaceae (11) and Bromeliaceae (9) are the most species-rich families. On the inselberg the plants are distributed in islands found on exposed rock, in fissures and in depressions in the rock. Variations in species richness in the region were assessed by comparison of floristic inventories conducted in other inselbergs of the semi-arid region with those of this study. The flora of the inselberg under investigation is more similar to the flora of other nearby inselbergs than to the vegetation of the surrounding semi-arid region.
(Taxonomic applications of leaf anatomy of the Brazilian species of Hypolytrum Rich. (Cyperaceae)). Hypolytrum Rich. (subfamily Mapanioideae) has a pantropical distribution being represented in the Neotropics by 16-21 species, most of them growing in several Brazilian ecosystems. Informations from foliar anatomy was analysed for 10 species of the genus. The most useful characters detected in Hypolytrum species studied here are: the shape of the leaves in cross section, the occurrence of granules (probably formed by silica) on the epidermal cells; features of the cuticle, the hypoderm and the aerenchymatous parenchyma; the number of layers and origin (hypodermal and epidermal) of bulliform cells; the presence of papillae on the abaxial face of the epidermis; and occurence of radiate parenchyma on the smaller bundles. Studies of foliar anatomy showed to be useful in generic and specific delimitation but do not support the taxonomic sections established.RESUMO (Aplicações taxonômicas da anatomia foliar das espécies brasileiras de Hypolytrum Rich. (Cyperaceae)). Hypolytrum Rich. (subfamília Mapanioideae) tem distribuição pantropical e está representado por 16-21 espécies na região Neotropical, das quais grande parte ocorre no Brasil habitando diferentes ecossistemas. São apresentados dados de anatomia foliar com maior relevância taxonômica para 10 espécies do gênero. Entre eles, destacam-se: formato da folha em secção transversal; presença de grânulos, provavelmente de sílica, em células epidérmicas; aspectos da cutícula, da hipoderme e do parênquima lacunoso; número de camadas e origem (hipodérmica e epidérmica) das células buliformes; presença de células epidérmicas papilosas; e ocorrência de parênquima radiado nos feixes menores. Os estudos de anatomia foliar mostram-se relevantes na delimitação genérica e específica, porém não apoiam as secções taxonômicas estabelecidas.
-(Floristic diversity of two crystalline rocky outcrops in the Brazilian northeast semi-arid region). Floristic composition and structure of vegetation were studied in two rocky outcrop areas in the semi-arid region of northeastern Brazil. From April 2007 to September 2008, 18 monthly field trips were carried out. Vascular plants were randomly collected throughout the outcrop areas. For structural analysis, 30 plots of 1 × 1 m were set in the vegetation islands. The checklist presented combines 211 species (69 families and 168 genera), although only 56 species were collected in the plots. Fabaceae (18 spp.; 8.5%), Asteraceae (17 spp.; 8%), Orchidaceae (13 spp.; 6.1%), Euphorbiaceae (13 spp.; 6.1%), Bromeliaceae (10 spp.; 4.7%), and Poaceae (eight spp.; 3.8%) are the richest families. Overall, 1,792 shrub and herbaceous specimens were counted in the plots. The Shannon-Wiener (H) diversity index values were 2.572 and 2.547 nats individual -1 . The species that presented the highest absolute abundance values (number of plants) had low frequencies in the plots and vice-versa. The biological spectrum had a high proportion of phanerophytes and therophytes, followed by cryptophytes, chamaephytes, and hemicryptophytes. The studied flora shares floristic components similar to other rocky outcrop areas of the semi-arid region in northeastern Brazil, including in relation to dominant groups in the vegetation structure.Key words -Caatinga, inselbergs, life-forms, saxicolous plants RESUMO -(Diversidade florística de dois afloramentos rochosos cristalinos no semi-árido, nordeste do Brasil).Composição florística e estrutura da vegetação foram estudadas em dois afloramentos rochosos localizados no semi-árido do nordeste do Brasil. Foram realizadas 18 excursões mensais, de abril de 2007 a setembro de 2008. Plantas vasculares foram coletadas aleatoriamente, no afloramento como um todo. Para análise estrutural foram plotadas 30 parcelas de 1 × 1 m nas ilhas de vegetação. Foram encontradas 211 espécies (69 famílias e 168 gêneros), entretanto somente 56 espécies foram coletadas nas parcelas. As famílias com maior número de espécies foram Fabaceae (18 spp.; 9%), Asteraceae (17 spp.; 8,5%), Orchidaceae (13 spp.; 6,5%), Euphorbiaceae (13 spp.; 6,5%), Bromeliaceae (10 spp.; 5%) e Poaceae (oito spp.; 4%). Ao todo, foram contabilizados, nas parcelas, 1.792 indivíduos herbáceos e arbustivos. Os valores do índice de diversidade de Shannon-Wiener (H) foram de 2,572 e 2,547 nats ind.-1 . As espécies que apresentaram maiores densidade apresentaram baixa freqüência nas parcelas e vice-versa. O espectro biológico apresentou alta proporção de fanerófitos e terófitos, seguidos por criptófitos, caméfitos e hemi-criptófitos. A flora estudada compartilha conjunto florístico semelhante a outros afloramentos rochosos do Nordeste do Brasil, inclusive em termos de grupos dominantes na estrutura da vegetação.Palavras-chave -Caatinga, formas de vida, inselbergues, plantas saxícolas 1.
RESUMO -(Morfologia de nectários em Leguminosae senso lato em áreas de caatinga no Brasil). Nectários extrafl orais (Nefs) são glândulas secretoras de néctar encontradas em diversas espécies de Angiospermas, inclusive Leguminosae. Essas estruturas podem se apresentar sob diferentes formas (elevados, embebidos; com ou sem estipe; cores distintas) e posições nas plantas (na raque, no pecíolo), sendo essas características relevantes aos estudos de taxonomia e sistemática. Este trabalho analisou a diversidade morfológica dos Nefs em Leguminosae de uma área prioritária para a conservação da caatinga no Estado de Pernambuco. As 35 espécies de Legumionsae estudadas foram coletadas no Município de Mirandiba, no semi-árido Pernambucano, e submetidas às técnicas usuais para análise e descrição morfológica. Entre essas espécies, foram caracterizados Nefs com origem primária (não substitutivos) e secundária (substitutivos). Dois diferentes tipos com onze formatos distintos foram encontrados entre elas. Uma grande variedade de localização, coloração, projeção, e dimensão foram registradas aqui. Uma chave de identifi cação e ilustrações foram elaboradas também. Os dados apresentados aqui ampliam o número de espécies estudadas com Nefs para a família, e também confi rmam a importância taxonômica e ecológica dessas estruturas para os legumes da região do semi-árido do Brasil. Palavras-chave: Glândulas, morfologia, néctar, sistemática ABSTRACT -(Nectary morphology of Leguminosae senso lato in areas of dry seasonal forest in Brazil). Extrafl oral nectaries (Efns) are nectar secreting glands found in many species of Angiosperms, including Leguminosae. These structures have various forms (elevated, embedded; stalk present or not; different colors) and positions on the plants (on the rachis, on the petiole), and these characteristics are relevant to taxonomy and morphology studies. This work analyses the morphological diversity of Efns in Leguminosae from a priority conservation area of caatinga in Pernambuco state. The 35 Leguminosae species studied were collected in Mirandiba municipality, a semi-arid region of Pernambuco and submitted to the usual techniques of anatomy and morphology analyses. Among these species, Efns with primary (non-substitutive) and secondary (substitutive) origin were characterized. Two different kinds and eleven distinct Efns forms were found. A large variety of placement, color, shape, and size are reported here. An identifi cation key and illustrations are also provided. Our data increased the number of species studied with Efns in the family, and also confi rm the taxonomic and ecological importance of this structure for legumes from the semi-arid region of Brazil.
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