ABSTRACT
Introducción: Las investigaciones sobre la ontogenia de los esporangios y más aún, de la estructura y función de las escamas receptaculares presentes en los soros de algunas especies de helechos, son escasos en la literatura científica. Objetivos: Describir y analizar la ontogenia de los esporangios y las escamas receptaculares de Pleopeltis macrocarpa. Metodología: Durante marzo y mayo de 2017 se recolectaron frondas fértiles de esta especie en los troncos de árboles en el vivero El Edén de las Flores en el municipio de Rionegro, Antioquia-Colombia. Las muestras se fijaron y procesaron de acuerdo a protocolos estándar para la inclusión y corte en parafina y resina. Las secciones obtenidas en resina (0.5 µm) se tiñeron con azul de Toluidina. Para descripciones adicionales sobre la anatomía e histoquímica se aplicaron reactivos específicos para determinar paredes primarias, secundarias, núcleos, lignina, polifenoles, polisacáridos, sustancias pécticas y celulosa. Las observaciones y registro fotográfico se efectuaron con microscopio fotónico y microscopía de epifluorescencia. Para observaciones con microscopía electrónica de barrido (MEB), los soros se deshidrataron con 2,2 dimetoxipropano, se desecaron a punto crítico y se metalizaron con oro. Resultados: Los soros son superficiales, vascularizados y de desarrollo mixto y están cubiertos por escamas receptaculares que se desprenden con la maduración de los esporangios. El esporangio de tipo leptosporangio tiene pedicelos largos de paredes primarias, anillos de los esporangios muestran paredes secundarias con engrosamientos en forma de "U" ricos en lignina. Las células epidérmicas de los receptáculos originan a los esporangios y las escamas receptaculares. Los eventos de división mitótica de estas dos estructuras son inicialmente similares, pero luego divergen para la diferenciación reproductiva y vegetativa de estos dos órganos. La meiosis es simultánea y las tétradas de esporas se disponen de forma decusada o tetragonal. El tapete celular es inicialmente uniestratificado pero por una división mitótica se torna biestratificado. Las células del estrato interno del tapete se rompen dando origen a un tapete plasmodial. En el desarrollo del esporodermo, primero se forma el exosporio, compuesto por esporopolenina, luego el endosporio compuesto de celulosa, pectina y polisacáridos carboxilados y finalmente el perisporio. Los resultados histoquímicos y de epifluorescencia indican que las paredes celulares tanto de los esporangios como las escamas receptaculares inmaduras son de naturaleza celulósica. Al madurar, estas estructuras, así como las células de la pared del esporangio mantienen esta composición. En tanto que las células epidérmicas de los escudos de las escamas receptaculares maduras se caracterizan por mostrar cutícula engrosada. Los polifenoles están presentes durante todas las etapas de desarrollo de los esporangios y escamas receptaculares. Los almidones son abundantes en etapas tempranas del desarrollo en las células del receptáculo y primordios de los esporangios. Conclusiones: La ontogenia de los esporangios de P. macrocarpa es similar al descrito para helechos leptosporangidos. Las escamas receptaculares son estructuras principalmente de protección, su morfología y composición de las paredes celulares evitan la desecación o perdida de humedad en los esporangios durante las etapas lábiles de su desarrollo. Estos resultados concuerdan con la función de protección atribuida a las escamas peltadas pluricelulares presentes en las estructuras vegetativas de algunas especies de helechos y angiospermas tolerantes a la sequía.
Introduction: The ontogeny of sporangia and furthermore the structure and function of the receptacle scales showed by the sori of some fern species are topics scarcely represented in the scientific literature. Objectives: To describe and analyze the ontogeny of sporangia and receptacle scales of Pleopeltis macrocarpa. Methods: During March and April of 2017, fertile fronds of P. macrocarpa were collected from tree stems located in the plant nursery "El Edén de las flores", municipality of Rionegro, Antioquia, Colombia. The samples were fixed and processed according to the standard protocols for embedding and sectioning in paraffin and resin. Sections obtained in resin (0.5 µm) were stained with Toluidine blue. The additional descriptions of the anatomy and histochemistry required specific reagents, applied for the determination of primary walls, secondary walls, nuclei, lignin, polyphenols, polysaccharides, pectic substances and cellulose. The observations and photographic records were performed by photonic and epifluorescence microscopy. For the scanning electron microscopy (SEM) technique, the sori were dehydrated with 2,2- Dimethoxypropane, dried to critical point and coated with gold. Results: The sori are superficial, vascularized and have mixed development, covered by receptacle scales that detach as the sporangia reaches maturity. The leptosporangiate type sporangium have long stalks of primary walls, the annulus of the sporangia shows secondary walls with "U" shaped thickenings rich in lignin. The epidermal cells of the receptacle originate the sporangia and receptacle scales. The mitotic division events of these two structures are initially similar, but then diverge for the reproductive and vegetative differentiation of these two organs. Meiosis is simultaneous and the spore tetrads are arranged in a decussate or tetragonal shape. The cellular tapetum is initially unstratified but becomes bistratified by mitotic division. The inner layer of the tapetum cells break originating a plasmodial tapetum. During the sporoderm development, the first structure formed is the exospore, composed of sporopolenin, followed by the endospore composed of cellulose, pectin and carboxilated polysaccharides, and finally the perispore. The histochemistry and epifluorescence results indicate that both the sporangia and immature receptacle scales have cell walls of cellulosic. These structures as well as those of the sporangium wall cells maintain its composition during maturation. Whereas, the epidermal wall cells of the shields from the mature receptacle scales are characterized by thickened cuticle. The polyphenols are present during all the development stages of the sporangia and receptacle scales. Starch is abundant in the early stages of development of the receptacle cells and sporangial primordia. Conclusions: The ontogeny of the sporangia of P. macrocarpa is similar to the described for leptosporangiate ferns. The receptacle scales are mainly protective structures, its morphology and cell wall composition prevent desiccation or humidity loss of the sporangia during the labile stages of development. These results agree with the protective function attributed to the peltated pluricellular scales present in the vegetative structures of drought tolerant species of ferns and angiosperms.
ABSTRACT
BACKGROUND:Modern research shows that Drynaria can delay celldegeneration and reduce the incidence of osteoarthritis. OBJECTIVE:To observe the proliferation and differentiation of rabbit bone marrow mesenchymal stem cells induced by different dosages of Drynaria freeze-dried powder, and to explore the optimum induction concentration. METHODS:Rabbit bone marrow mesenchymal stem cells were isolated and cultured in vitro by density gradient centrifugation and adherence screening methods, and then divided into blank group, positive control group (transforming growth factorβ1), high-, middle-, low-dosage Drynaria groups (0.4 mg, 0.1 mg, 5μg). Passage 3 cells were selected and cultured in different media. After 1 week, cellviability was detected by MTT method, and expression of type II col agen by immunohistochemical method. RESULTS AND CONCLUSION:Both transforming growth factorβ1 and Drynaria could improve the proliferation of bone marrow mesenchymal stem cells, and the increase in cellproliferation was ranked as fol ows:positive control group>low-dosage group>middle-dosage group>high-dosage group>blank group. Bone marrow mesenchymal stem cells were differentiated into chondrocytes under induction of transforming growth factorβ1 and Drynaria, and induced cells significantly expressed type II col agen. The expression of type II col agen was ranked as fol ows:positive control group>low-dosage group>middle-dosage group>high-dosage group>blank group. These findings suggest that Drynaria can promote the proliferation and differentiation of rabbit bone marrow mesenchymal stem cells, and the optimal dosage is 5μg.
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BACKGROUND:At present, there are many methods to treat cartilage defects, but none radical y repairs the articular cartilage defects. OBJECTIVE:To histological y verify the effect of naringin combined with tissue engineering cartilage on the repair of rabbit articular cartilage defects. METHODS:Rabbit bone marrow mesenchymal stem cells fol owing in vitro proliferation were compounded onto acellular dermal matrix, which was then implanted into rabbit knee cartilage defects. Naringin was also given by lavage. Hematoxylin-eosin staining, Masson trichrome staining, toluidine blue dyeing, type II col agen staining and type X col agen staining were performed in the repaired tissue. RESULTS AND CONCLUSION:After 8 weeks post-surgery, the defects repaired with the naringin and stem cells composite were turned into milky-white and transparent smooth tissue. The defective tissue which was repaired, was very similar to normal cartilage tissue, with smooth surface. After the histology research, we found that the defect tissue was fil ed with new cartilage tissue. Results indicated that naringin combined with tissue engineering cartilage can promote the repair of articular cartilage defects in rabbits.
ABSTRACT
Architecture and leaf anatomy of the Polypodium plesiosorum sensu Moran complex (Polypodiaceae). The Polypodium plesisorum complex is a heterogeneous morphology group. We studied leaf architecture and anatomy of 12 species of this group, in addition to other 23 species of Polypodium (P. dulce, P. polypodioides and P. vulgare complex sensu Moran) and related genera (Goniophlebium, Phlebodium, Pleopeltis, Serpocaulon, Synammia), for comparative purposes. Two homogeneous groups of species were established in P. plesiosorum complex. One of them is recognized based on the type of anastomosis of the veins (Type III): Polypodium conterminans (originally considered in the group of P. dulce with free venation by Moran), P. hispidulum, P. plesiosorum and P. rhodopleuron. The second group with Polypodium arcanum, P. castaneum, P. colpodes, P. eatonii, and P. flagellare were recognized based on the type of anastomosis of the veins (Type IV) and how vascular strands fuse along the petiole-leaf rachis. Characters studied helped to group the remaining species with other groups outside the complex under study. Rev. Biol. Trop. 58 (3): 955-976. Epub 2010 September 01.
El complejo Polypodium plesisorum es un grupo de morfología heterogénea. Se estudió la arquitectura y anatomía foliar de 12 especies que constituyen el complejo de Polypodium plesiosorum reconocidas por Moran, y otras 23 especies de Polypodium (complejos P. dulce, P. polypodioides y P. vulgare sunsu Moran) y géneros relacionados taxonómicamente (Goniophlebium, Phlebodium, Pleopeltis, Serpocaulon, Synammia) con fines comparativos. Dos grupos de especies homogéneas fueron establecidos en el complejo P. plesisorum. Uno de ellos se reconoce por el tipo de anastomosis de las venas (tipo III): Polypodium conterminans (originalmente considerado en el grupo de P. dulce de venación libre según Moran), P. hispidulum, P. plesiosorum y P. rhodopleuron. El segundo grupo formado por Polypodium arcanum, P. castaneum, P. colpodes, P. eatonii y P. flagellare, se reconoce por el tipo de anastomosis de las venas (tipo IV) y la forma en que se fusionan los cordones vasculares a lo largo del eje pecíoloraquis de la hoja. Los caracteres estudiados ayudaron a relacionar las especies restantes con otros grupos fuera del complejo estudiado.