Abstract 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.

Due to the scarce information about the root organization of Galeandra genus representatives, this study aimed to describe the root anatomy of Galeandra leptoceras, describing adaptations related to hydric relations and characters of taxonomic interest. Five roots of three plants were fixed and preserved in 50% alcohol. These ones were cut in midline with the use of razors. The sections were stained with 0.05% Safrablau and mounted in glycerin. It was observed that the roots of species are structurally adapted to epiphytism; however, some anatomical features show that this species requires more frequent watering or environments with constant humidity. The anatomical characteristics described for roots support results reported by authors that include the genus in subtribe Catasetinae, Cymbidieae tribe. The anatomical characters have generic uniformity, serving as a tool for the genus’s systematic.

Vanilla planifolia é uma espécie com grande valor comercial, porém sua propagação é dificultada devido à baixa germinação de suas sementes. No presente estudo procurou-se avaliar a influência da escarificação destas sementes por meio da imersão em H2SO4 concentrado durante 60, 120 e 180 segundos, bem como de diferentes concentrações de nitrogênio sobre a germinação e o desenvolvimento das plântulas. Sessenta segundos de escarificação e 25% de nitrogênio no meio de cultura proporcionaram os melhores resultados sobre a germinação e desenvolvimento de V. planifolia, constituindo-se em um procedimento viável para a produção comercial dessa espécie.

Vanilla planifolia is a species with a large commercial value; however, it is difficult to propagate due to low seeds germination. In the present study we aimed to evaluate the influence of scarification of the seeds by soaking them in concentrated H2SO4 for 60, 120 and 180 seconds, as well as different concentrations of nitrogen, on germination and plant development. Sixty seconds of scarification and 25% nitrogen in the culture medium provided the best results for germination and is a viable procedure for the commercial production of this species.

One of the ways to increase the production of plants with good genetic quality and conserve orchid species in danger of extinction has been the in vivo propagation. Different culture media have been developed to obtain more efficient results and simplified protocols in an attempt to obtain quality plants at low cost. In consideration of the above and the importance of species conservation, the objective of this study was to develop in vivo propagation of Schomburgkia gloriosa with simplified culture medium. The experimental design was completely randomized, in which seeds were grown in MS medium with half concentration of macronutrients and two other media based on Hyponex® and Kristalon laranja®. The results after 180 days showed that the MS medium composed of half concentration of macronutrients produced the best in vitro results to seeds, since it produced the greatest plant height, plant fresh weight and length of roots and leaves. As well as being the most efficient, the use of this medium reduces costs, thus it is a viable alternative for production of plantlets with both commercial and ecological ends.

Uma das formas de aumentar a produção de mudas com qualidade genética e conservar espécies de orquídeas ameaçadas de extinção tem sido a propagação in vitro. Diferentes formulações de meios de cultura têm sido desenvolvidas na tentativa de se obter meios eficazes e de protocolo simplificado, a fim de se produzir plantas com qualidade e custo reduzido. Considerando a importância da conservação de espécies de orquídeas e a obtenção de plantas com qualidade e menor custo, este trabalho teve como objetivo realizar a propagação in vitro de Schomburgkia gloriosa utilizando os meios de cultura simplificados. Para tal, foi realizado um experimento em delineamento inteiramente casualizado no qual sementes foram inoculadas em meio MS com metade da concentração de macro-nutrientes e outros dois meios à base dos fertilizantes Hyponex® e Kristalon laranja®. Após 180 dias de experimento, verificou-se que o meio de cultura que proporcionou maior eficiência no desenvolvimento in vitro de sementes foi o MS, composto por metade da concentração de macronutrientes, pois apresentou os maiores valores médios para as variáveis: altura da planta, peso da matéria fresca e comprimento da maior raiz e folha. Além deste meio de cultura ser mais eficiente, sua utilização reduz custos, o que pode viabilizar tanto a produção de mudas com finalidade comercial quanto ecológica.

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.

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.

The Cattleya genus has a great importance in the flower agro-business market. Fusarium wilts, caused by Fusarium oxysporum f. sp. cattleyae, is considered one of the main factors of decline and death of plants of this genus. Using seven hybrids (intra and intergenerics) of Cattleya, tests of resistance and susceptibility to F. oxysporum were performed in conditions of greenhouse for 12 months, using, as evaluation criterion, a scale of the disease severity ranging from one (resistant) to eight (highly susceptible). High susceptibility to the fungus by Cattleya Nobile's Wax Toy, Cattleya Orquidacea's Mister Fast intrageneric hybrids and Potinara Orquidacea's Havana Brown intergeneric hybrid, related to Brassocattleya Orquidacea's Melody intergeneric hybrid, high resistance to the pathogens was observed.