Oncidium Flexuosum Research Articles

INVENTARISATION OF ORCHID TYPES (Orchidaceae) IN WEST TOMOHON AREA

This study aims to inventory orchid species in the West Tomohon area using the accidental sampling method of exploration in a predetermined place. Orchids are a type of flowering plant that comes from the Orchidaceae family. Each type of orchid has its own characteristics. Tomohon City has abundant natural resources, including ornamental plants such as orchids. Data on orchid diversity in West Tomohon Sub-district has never been reported. Orchid inventory is an activity that records the diversity of orchid species in an area. This research is descriptive-qualitative research. The results of this study have yielded 10 species of orchids belonging to nine genera in one family. The orchid species found in the West Tomohon area consist of Arachnis sp., Arundina graminifolia, Cattleya sp., Dendrobium biggibum, Dendrobium moschatum, Epidendrum secundum, Oncidium flexuosum, Phaius tankervilleae, Phalaenopsis amabilis, and Vanda arcuata. The most common orchid found in this area is the moon orchid, Phalaenopsis amabilis.

Studies on the Perimeter : Protoxylem Ratios in Twelve Domesticated Orchid Species

The present study was aimed at ranking twelve domesticated orchid species based on ANOVA of their Perimeter : Protoxylem arch ratios. Two terrestrial orchids, Spathoglottis plicata Blume , Peristeria elata Hook and ten epiphytic orchids, Oncidium flexuosum Sims., Dendrobium crumenatum Sw., Dendrobium var. sonia, Arachnis flosaeris (L.) Rchb. f, Vanda sp., Phalaenopsis equestris (Schauer) Rchb. f., Doritis pulcherrima var. marmorata, Acampe sp., Vanilla sp. and Epidendrum sp. were selected for the present study. The P: Px ratio was observed to correlate with the water adaptive efficiency of the orchids.

Efeito de bioestimulante composto de cinetina, ácido indolbutírico e ácido giberélico em epífitas, visando a restauração florestal

RESUMO Com objetivo de introdução de epífitas em manejo de restauração florestal, foi avaliado o efeito da aplicação de bioestimulante no desenvolvimento de três espécies epífitas sob condição de arboreto. Plantas das espécies Vriesea carinata Wawra (Bromeliaceae), Oncidium flexuosum Sims (Orchidaceae) e Rhipsalis paradoxa (Salm-Dyck ex Pfeiff.) Salm-Dyck (Cactaceae) foram pulverizadas, com o bioestimulante Stimulate® nas concentrações de 0,0, 4,0, 8,0 e 12,0 mL L-1. Estacas de Chorisia speciosa foram utilizadas como suporte e substrato para a fixação das plantas. As variáveis analisadas foram: qualidade da fixação, número de folhas, brotos e raízes e, matéria seca da parte aérea e raízes. O delineamento experimental foi em blocos ao acaso constituído de quatro tratamentos (concentrações do bioestimulante) com três repetições de cinco plantas, totalizando 15 plantas por tratamento, para cada espécie. Os dados foram submetidos à análise de variância e regressão. Os tratamentos 4 e 8 mL L-1 de bioestimulante proporcionou aumento da produção de folhas e do diâmetro do caule de V. carinata, enquanto que as demais variáveis analisadas, nas três espécies, não apresentaram diferenças significativas entre os tratamentos. Nas condições do experimento, o bioestimulante não apresentou respostas significativas quanto ao crescimento, desenvolvimento do sistema radicular e à qualidade da fixação para as espécies estudadas; estimulando, no entanto, o crescimento da parte aérea de V. carinata e O. flexuosum. A facilidade de aplicação do bioestimulante, proporcionando o crescimento da parte aérea e o baixo custo do produto, possibilita a sua utilização no estímulo do crescimento de plantas epífitas a serem utilizadas na restauração florestal.

Cryopreservation, early seedling development, and genetic stability of Oncidium flexuosum Sims

An efficient cryopreservation protocol was developed for mature seeds of Oncidium flexuosum Sims. Seed morphology, protocorm formation, and early seedling development were also assessed. The effects of phloroglucinol and Supercool X-1000® as cryoprotectant additives in the vitrification solution were investigated. Dehydration using the plant vitrification solution 2 (PVS2) for 60 and 120 min prior to immersion in liquid nitrogen promoted the highest frequency of in vitro seed germination 6 weeks following culture on half-strength Murashige and Skoog (½ MS) medium. Mature seeds submitted to vitrification for 120 min in PVS2 and 1 % phloroglucinol at 0 °C enhanced germination by 68 %, whereas in PVS2 and 1 % Supercool X-1000® germination was just moderately enhanced (26 %). In vitro-germinating seedlings developed healthy shoots and roots without the use of plant growth regulators. After 6 months of growth, there were no differences between in vitro- and ex vitro-grown seedlings for various phenotypic characteristics, including shoot length, number of leaves, number and length of roots, and fresh and dry weight. Seedlings were transferred to greenhouse conditions and successfully acclimatized, further developing into normal plants with over 90 % survival. Comparative analysis of seedlings from control and vitrified seeds using flow cytometry indicated that no change in ploidy levels occurred as a result of cryopreservation, therefore maintaining seedlings genetic stability. In this study, vitrification with PVS2 for 120 min with the addition of 1 % phloroglucinol offers a simple, safe, and feasible protocol for cryopreservation of O. flexuosum mature seeds.

Mônica Piacentini Luizon1, Caroline Santos Oliveira1, Danielly Kathe Zaqueo1, Jaqueline Aparecida Oliveira1, Gustavo Ligieri Pereira do Prado2, Renata Barbieri1, Fernanda Oliveira Gaspari de Gaspi1, João Ernesto de Carvalho3, Elaine Cristina Mathias da Silva-Zacarin4, Camila Andréa Oliveira5, Acácio Antônio Pigoso1 and Grasiela Dias de Campos Severi-Aguiar5*

Oncidium flexuosum Sims. is an orchidwhose leaves are frequently used for therapeutic applications although its action mechanism is not exactly understood. So the aim of this study was investigate its effects in Wistar rat liver, kidney and bone marrow. For this purpose, twenty-five adult male Wistar rats were divided into five groups of 5 animals each: a control group receiving only water, a positive control receiving a mutagen compound and three groups treated for 15 days with 100, 250 or 500 mg/kg/day of a crude hydroalcoholic leaf extract of O. flexusosum Sims. No significant alterations were observed in –SH groups, MDA or catalase, showing that the extract does not induce hepatic oxidative damage. There was no evidence of kidney injury and hepatic function alteration (ALT). However, significant mitochondrial swelling was observed in the treated groups and is probably related to cell death induction observed in cells that displayed acidophilia, pyknosis and positive labeling with the TUNEL technique at higher concentrations of the extract. We demonstrated that the hepatotoxicity of the extract resulted from its ability to induce DNA and mitochondrial damage that arrests cells, leading to cell death, probably caused by the flavonoidsand tannins present in this extract.

Anatomical development of the pericarp and seed of Oncidium flexuosum Sims (ORCHIDACEAE)

Interpretation of the anatomical structure of the ovary and fruit of the Orchidaceae family is still controversial, which makes it difficult to understand the development and dehiscence of the fruit. The genus Oncidium is polyphyletic and is currently the subject of taxonomic studies. In this study, we have investigated the anatomical development of the pericarp and seed of Oncidium flexuosum Sims to determine important diagnostic characters that, along with molecular data, can assist in defining this group. We have found a new anatomical characteristic of the family: the presence of precursor cells for fruit dehiscence, which were visible from the beginning of development and located on the outer walls of the sterile valves. In contrast with what has been observed by different authors with other species, in the mature fruit of O. flexuosum, only the endocarp of the fertile valves and a few cells near the exocarp and the vascular bundle in the sterile valves show parietal thickening, while the rest remains parenchymatous. During the development of the ovule and embryo, we have shown that the embryonic sac of this species has eight nuclei and that the embryo has a long and elaborate suspensor.

Effects of the Topical Application of Hydroalcoholic Leaf Extract of Oncidium flexuosum Sims. (Orchidaceae) and Microcurrent on the Healing of Wounds Surgically Induced in Wistar Rats.

This study evaluated the wound healing activity of hydroalcoholic leaf extract of Oncidium flexuosum Sims. (Orchidaceae), an important native plant of Brazil, combined or not with microcurrent stimulation. Wistar rats were randomly divided into four groups of nine animals: control (C), topical application of the extract (OF), treated with a microcurrent (10 μA/2 min) (MC), and topical application of the extract plus microcurrent (OF + MC). Tissue samples were obtained 2, 6, and 10 days after injury and submitted to structural and morphometric analysis. The simultaneous application of OF + MC was found to be highly effective in terms of the parameters analyzed (P < .05), with positive effects on the area of newly formed tissue, number of fibroblasts, number of newly formed blood vessels, and epithelial thickness. Morphometric data confirmed the structural findings. The O. flexuosum leaf extract contains active compounds that speed the healing process, especially when applied simultaneously with microcurrent stimulation.

Direct regeneration of protocorm-like bodies (PLBs) from leaf apices of Oncidium flexuosum Sims (Orchidaceae)

The present study describes the direct regeneration of protocorm-like bodies (PLBs) in leaf explants of the tropical species Oncidium flexuosum. The explants were inoculated in a solid, modified Murashige and Skoog (MS) medium with different concentrations of the growth regulator thidiazuron (TDZ) and with or without 2,4-dichlorophenoxyacetic acid (2,4-D) and naphthalene acetic acid (NAA), and kept away from light or in a 16-h photoperiod. The presence of auxins, 2,4-D, and NAA inhibited the formation of PLBs. The highest frequency of explants that regenerated PLBs (80%) was obtained when they were maintained in a culture medium containing 1.5 μM TDZ under dark conditions. In the same culture medium but under a 16-h photoperiod, 95% of the leaf explants presented necrosis. Therefore, darkness was crucial for the regeneration of PLBs in O. flexuosum leaf explants, which is in disagreement with the literature. PLBs developed from the division of epidermal and subepidermal cells mainly on the adaxial side of the apex region of the explant. Plants with well-developed leaves and roots grew after the PLBs were transferred to growth regulator-free medium under a 16-h photoperiod.

Semente de amendoeira (Terminalia catappa L.) (Combretaceae) como substrato para o cultivo de orquídeas epífitas

The use of Terminalia catappa L. (Combretaceae) seeds as a substrate for growing orchids of the species Oncidium flexuosum Sims, Dendrobium nobile Lindl. and Brassavola tuberculata Hook was compared to the tree fern fiber Dicksonia sellowiana Hook, largely used for that purpose. This species is endangered and its exploitation is prohibited by law. After twelve months, the following parameters were evaluated: aerial part height, pseudo bulb diameter, number of pseudo bulbs and pH of substrate. There was no significant interaction between substrates and species for the evaluated parameters. The orchids developed on T. catappa substrate and tree fern fiber showed similar aerial parts, diameter and number of pseudo bulbs. T. catappa substrate showed a low rate of decomposition, which maintained good aeration capacity, root development and pH values close to that found on tree fern fiber. T. catappa used as a substrate is viable as a substitute for tree fern fiber in the cultivation of these orchid species.

Armazenamento de sementes de orquídeas

Sementes de dezesseis espécies de orquídeas foram armazenadas a 5ºC por até 42 meses, sendo verificada a viabilidade pelo teste de tetrazólio e de germinação. Houve perda da viabilidade conforme incremento no período de armazenamento. Por doze meses, a maioria das espécies estocadas a 5ºC, em dessecador com umidade relativa de ± 6% de conteúdo de água, conservou a viabilidade próxima aos 100%, com exceção da Cattleya labiata que apresentou queda de cerca de 50% da viabilidade inicial. Cattleya intermedia, Encyclia pygmaea, E. odorantissima, Grobya sp., Oncidium flexuosum, Oncidium pumilum e um híbrido natural, Laeliocattleya conservaram, em geladeira, a viabilidade das sementes acima de 90%, por até 24 meses. Para Cattleya intermédia, realizou-se armazenamento de sementes em tubos de polipropileno a 5, -18 e a 25ºC, em dessecador ou condições ambientais sem controle de umidade. Em condições de laboratório houve perda quase total da viabilidade das sementes. A estocagem em geladeira a 5ºC ou em "freezer" a - 18ºC fornece condições adequadas para conservar a viabilidade de sementes de orquídeas. Com essa mesma espécie, as sementes foram armazenadas a -18ºC durante 24 semanas, sendo testada semanalmente sua viabilidade. Para tais avaliações, as sementes eram transferidas diretamente de -18ºC para temperatura ambiente de laboratório (25ºC) ou indiretamente, por uma hora a 5ºC, depois para temperatura ambiente por uma hora. A transferência indireta foi mais eficiente na conservação da viabilidade.

Indução in vitro da germinação de sementes de Oncidium flexuosum (Orchidaceae) por fungos micorrízicos rizoctonióides

A germinação de sementes e o desenvolvimento de protocórmios de Oncidium flexuosum (Orchidaceae) induzidos simbioticamente são descritos pela primeira vez. As sementes de O. flexuosum foram inoculadas com dez fungos micorrízicos rizoctonióides, previamente isolados de micorrizas de dez espécies de orquídeas neotropicais do Brasil, incluindo O. flexuosum. Foram utilizados um isolado pertencente à espécie Epulorhiza repens, dois pertencentes à Epulorhiza epiphytica, seis de Ceratorhiza spp. e um de Rhizoctonia sp. Sementes inoculadas com o isolado M2 de Ceratorhiza sp., originalmente isolado do sistema radicular de O. flexuosum em habitat natural, promoveu a germinação das sementes em sete dias e em, aproximadamente, 30 % das plântulas, houve formação de folhas após 50 dias de incubação, apresentando pelotons em algumas células do protocórmio e das radicelas. Os demais isolados promoveram a germinação das sementes; entretanto, não promoveram um desenvolvimento ótimo dos protocórmios. Sementes incubadas na ausência de fungos micorrízicos não germinaram. A especificidade e a alta dependência de O. flexuosum pela associação micorrízica ficaram claras. Aspectos relativos à especificidade, anatomia da interação fungo-planta e a importância da seleção de estirpes fúngicas, previamente ao uso de fungos micorrízicos para o cultivo simbiótico a partir de sementes de O. flexuosum são discutidos.