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The aim of this study was to evaluate the effect of 2.4-D and BAP on protocorm formation in meristematic regions of root and leaf of Miltonia spectabilis moreliana, and to test the effect of sucrose concentrations and pH levels on the growth of protocorms. Root and leaf segments of in vitro- germinated plants were cultured in MS/2 culture medium supplemented with 2.4-D and BAP, and kept in the dark for 210 days. The combination of 3 mg.L -1 2.4-D and 1 or 3 mg.L -1 BAP provided the best results. The concentrations of 15 and 30 g.L -1 sucrose, independently of the pH, were more efficient for the in vitro culture of this species, as they promoted an increase in the number and length of roots, height, and fresh weight of the plantlets. The pH was significant only in combination with 15 g.L -1 sucrose for the length of the largest root and fresh weight.

To elucidate the factors which control the flower phenotypic plasticity of Catasetum fimbriatum, studies focusing the floral development of the species were performed. The treatments were: high light intensity (1613 μmol.m-2.s-1); low light intensity (454 μmol.m-2.s-1) and mean light intensity (827 μmol.m-2.s-1). The floral morphology and anatomy were analyzed to evaluate of the sequence of tissue development involved in the sexual differentiation. We found the presence of cell cluster with meristematic features in the ovaries and gynostemium of the male and female diclinous flowers. These are responsible for the definition of the sexual expression of the species, in the dependence of the environmental stimulus, related to the endogenous concentration of ethylene, allowing, consequently, the dedifferentiation and re-differentiation of those clusters in the sexual determination of the flowers. There were no anatomical differences in floral tissues in different treatments. To elucidate the factors which control the flower phenotypic plasticity of Catasetum fimbriatum, studies focusing the floral development of the species were performed. The treatments were: high light intensity (1613 μmol.m-2.s-1); low light intensity (454 μmol.m-2.s-1) and mean light intensity (827 μmol.m-2.s-1). The floral morphology and anatomy were analyzed to evaluate of the sequence of tissue development involved in the sexual differentiation. We found the presence of cell cluster with meristematic features in the ovaries and gynostemium of the male and female diclinous flowers. These are responsible for the definition of the sexual expression of the species, in the dependence of the environmental stimulus, related to the endogenous concentration of ethylene, allowing, consequently, the dedifferentiation and re-differentiation of those clusters in the sexual determination of the flowers. There were no anatomical differences in floral tissues in different treatments.&nbsp

Considering that the root structure of the Brazilian genera belonging to the Catasetinae subtribe is poorly known, we describe the roots of twelve representatives from this subtribe. For anatomical analysis, the roots were fixed in FAA 50, preserved in ethanol 70% and sectioned at its medium region using razor blades. The sections were stained with 0.05% astra blue and safranin and mounted in glycerin. For the identification of starch we used Lugol's solution; for lignin, floroglucin chloridric; for lipids, Sudan III, and for flavanoids, potassium hydroxide. The relevant aspects were registered using a digital camera joined with an Olympus microspope (BX51 model). The structural similarities of all roots support the placement of the subtribe Catasetinae into the monophyletic tribe Cymbidieae. Some root features are restricted to one or two taxa and can be useful in the systematics of the subtribe. For example, the occurrence of flavonoidic crystals characterizes the genera Catasetum and Cychnodes, and the number of the velamen layers and the shape of the epivelamen cells are useful to confirm the taxonomic position of Clowesia amazonica. The presence of velamen and flavonoidic crystals was interpreted as an adaptation to the epiphytic habit.Considerando que a estrutura das raízes de gêneros brasileiros pertencentes à subtribo Catasetinae é pouco conhecida, descrevemos as raízes de doze representantes desta subtribo. Para análise anatômica, as raízes foram fixadas em FAA 50, preservadas em álcool 70% e seccionadas na sua região média usando lâminas de barbear. Os cortes foram corados com astra blue e Safrablau 0,05% e montados em glicerina. Para a identificação do amido, utilizou-se a solução de Lugol; da lignina, floroglucina clorídrica, dos lipídios, Sudan III e dos flavonóides, hidróxido de potássio. Os aspectos relevantes foram registrados usando câmera digital acoplada a um microscópio Olympus (modelo BX51). As semelhanças estruturais observadas entre todas as raízes estudadas confirmam a inclusão da subtribo Catasetinae na tribo monofilética Cymbidieae. Algumas características radiculares são restritas a um ou dois táxons e podem ser úteis na taxonomia da subtribo. Por exemplo, a ocorrência de cristais flavonoídicos caracteriza os gêneros Catasetum e Cychnodes e o número de camadas do velame associado à forma das células do epivelame são úteis para confirmar a posição taxonômica de Clowesia amazônica. A presença de velame e de cristais flavonoídicos foi interpretada como adaptações ao hábito epifítico.

The neotropical riparian forests are widely studied, but there are little informations about orchids in phytophisiognomies. The aim of this study was to characterize the floristic composition, and ecological relationship and categories related to habitat of Orchidaceae family representatives in riparian forest in Semideciduous Seasonal Forest fragment in Araras, SP. By the demarcation of 20 plots of 20 X 10 m (400 m2) parallel to the local water body, it was sampled 10 genera and 12 species: Baptistonia cornigera, Campylocentrum grisebachii, Campylocentrum robustum, Capanemia micromera, Catasetum fimbriatum, Cattleya loddigesii, Oeceoclades maculata, Pleurothallis miniato-lineolata, Polystachya estrellensis, Sacoila lanceolata and Lophiaris pumila. The existing populations of orchids in the study area decreased due to anthropogenic disturbance, resulting in the current low diversity. High densities presented by some species, chiefly L. pumila, make it clear the processes of recolonization related to adaptative mechanisms and to the current conservation status of the fragment. FLORÍSTICA E ECOLOGIA DE ORCHIDACEAE EM FRAGMENTO FLORESTAL ESTACIONAL SEMIDECIDUAL DE ARARAS, SÃO PAULO, BRASIL RESUMO: Os bosques ribeirinhos neotropicais são amplamente estudados, entretanto, existem poucas informações a respeito de orquídeas nestas fitofisionomias. O objetivo deste trabalho foi caracterizar a composição florística, a relação ecológica e categorias relacionadas com o habitat dos representantes da família Orchidaceae em fragmento Florestal Estacional Semidecidual ribeirinho em Araras (SP). Pela demarcação de 20 parcelas de 20 x 10 m (400 m2) paralelas ao corpo d’água local, foram amostrados 10 gêneros e 12 espécies: Baptistonia cornigera, Campylocentrum grisebachii, Campylocentrum robustum, Capanemia micromera, Catasetum fimbriatum, Cattleya loddigesii, Oeceoclades maculata, Pleurothallis miniato-lineolata, Polystachya estrellensis, Sacoila lanceolata e Lophiaris pumila. As populações de orquídeas existentes na área de estudo se reduziram devido à perturbação antropogênica, que resultou na baixa diversidade atual. As altas densidades apresentadas por algumas espécies, principalmente L. pumila, demonstram processos de recolonização relacionados com os mecanismos adaptativos e o estado de conservação atual do fragmento. PALAVRAS-CHAVE: Fitogeografia; Orquídeas; Taxonomia.

Habenaria repens é uma exceção entre as Orchidaceae devido à ampla distribuição geográfica e ao hábito emergente. O presente estudo objetivou analisar a distribuição espacial da espécie, além de verificar se há correlação entre imaturos e maturos com os padrões microclimáticos em Fragmento Estacional Semidecidual do Estado de São Paulo. A identificação do padrão de distribuição ocorreu pela alocação de 20 parcelas de 20 x 10 m, posteriormente reduzidas para 10 x 10 m, onde foram calculados o Índice de Morisita (IM) e a Razão Variância/Média (R). Para identificação das correlações utilizou-se o índice de correlação de Spearman (r). Imaturos e maturos apresentaram agregação nas parcelas de 100 m² e 200 m², sendo esta maior para maturos em ambos os casos. O índice de correlação obtido entre imaturos e maturos foi superior a 0.8, indicando dependência entre tais populações. Todos os fatores abióticos analisados mostraram-se importantes para a alocação das plantas ao longo das parcelas, com uma correlação moderada com as abundâncias. Habenaria Repens: Spacial Distribution and Co-relationship with Abiotic Factors of an Invasive Emergent Orchid in a Brazilian Mesophile Fragment Habenaria repens is an exception among Orchidaceae due to its wide distribution and emergent habits. Current analysis investigates the spatial distribution of the species and verifies whether there is a co-relationship between mature and immature by microclimate standards in a Semideciduous Seasional Fragment in the state of São Paulo, Brazil. The distribution standard was identified by 20 parcels measuring 20 x 10 m, later reduced to 10 x 10 m, where Morisita Index (MI) and Ratio Variance/Means (R) were calculated. Spearman´s correlation index (r) was employed to identify the correlations. Immature and mature had an aggregation in the 100 m² and 200 m² parcels, the latter being higher for mature ones in the two cases. Correlation index between immature and mature was higher than 0.8 and showed dependence between the populations. All the abiotic factors analyzed were important for plants throughout the parcels, with moderate correlation with abundances. KEYWORDS: Ontogenetic Stages; Orchidaceae; Spatial Standard.