Ontogenia e histoquímica de los esporangios y escamas receptaculares del helecho epífito Pleopeltis macrocarpa (Polypodiaceae)
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| Natura: | Artículo científico |
| Lingua: | es |
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Universidad de Costa Rica
2019
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| _version_ | 1876469414592774144 |
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| author | Edgar Javier Rincón Barón |
| author_facet | Edgar Javier Rincón Barón |
| contents | Ontogenia e histoquímica de los esporangios y escamas receptaculares del helecho epífito Pleopeltis macrocarpa (Polypodiaceae) Edgar Javier Rincón Barón Beatriz Elena Guerra Sierra David Esteban Restrepo Zuluaga Silvia Espinosa Matías Biología sori scales ontogeny sporangia Polypodiaceae 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 prote 2019 artículo científico 0034-7744 https://www.redalyc.org/articulo.oa?id=44965908016 https://www.redalyc.org/journal/449/44965908016/ https://www.redalyc.org/journal/449/44965908016/html/ https://www.redalyc.org/journal/449/44965908016/44965908016.epub https://www.redalyc.org/journal/449/44965908016/movil DOI 10.15517/RBT.V67I6.36984 es http://www.redalyc.org/revista.oa?id=449 Revista de Biología Tropical application/pdf Universidad de Costa Rica Revista de Biología Tropical (Costa Rica) Num.6 Vol.67 |
| format | Artículo científico |
| id | redalyc_44965908016 |
| institution | Redalyc |
| language | es |
| publishDate | 2019 |
| publisher | Universidad de Costa Rica |
| spellingShingle | Ontogenia e histoquímica de los esporangios y escamas receptaculares del helecho epífito Pleopeltis macrocarpa (Polypodiaceae) Edgar Javier Rincón Barón Biología sori scales ontogeny sporangia Polypodiaceae Ontogenia e histoquímica de los esporangios y escamas receptaculares del helecho epífito Pleopeltis macrocarpa (Polypodiaceae) Edgar Javier Rincón Barón Beatriz Elena Guerra Sierra David Esteban Restrepo Zuluaga Silvia Espinosa Matías Biología sori scales ontogeny sporangia Polypodiaceae 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 prote 2019 artículo científico 0034-7744 https://www.redalyc.org/articulo.oa?id=44965908016 https://www.redalyc.org/journal/449/44965908016/ https://www.redalyc.org/journal/449/44965908016/html/ https://www.redalyc.org/journal/449/44965908016/44965908016.epub https://www.redalyc.org/journal/449/44965908016/movil DOI 10.15517/RBT.V67I6.36984 es http://www.redalyc.org/revista.oa?id=449 Revista de Biología Tropical application/pdf Universidad de Costa Rica Revista de Biología Tropical (Costa Rica) Num.6 Vol.67 |
| title | Ontogenia e histoquímica de los esporangios y escamas receptaculares del helecho epífito Pleopeltis macrocarpa (Polypodiaceae) |
| topic | Biología sori scales ontogeny sporangia Polypodiaceae |
| url | https://www.redalyc.org/articulo.oa?id=44965908016 https://www.redalyc.org/journal/449/44965908016/ https://www.redalyc.org/journal/449/44965908016/html/ https://www.redalyc.org/journal/449/44965908016/44965908016.epub https://www.redalyc.org/journal/449/44965908016/movil |