ABSTRACT
Tabernaemontana catharinensis, conocida vulgarmente como lechero, es una especie perteneciente a la familia Apocynaceae. El actual estudio se refierea la morfología y la anatomía de la plántula de esta especie. Las semillas colectadas desde varios arboles creciendo en la planicie de la inundación del alto río Paraná, fueron germinadas en una cámara de germinación con una temperatura constante de 300C y mantenidas bajo luz fluorescente continua. El desarrollo de las plántulas ocurrió en un invernadero. La anatomía fue estudiada en plántulas fijadas en FAA 50. Este material fue seccionado transversalmente y las secciones obtenidas fueron teñidas en safranina y azul de astra. La plántula es fanerocotiledonar y epígea y presenta raíz axial, cuello, cotiledones ovados, epicótilo reducido, y eófilos lanceolados semejantes a los metáfilos. Su raíz es tetrarca. El hipocótilo y epicótilo tienen estructura caulinar y presentan crecimiento secundario cuya peridermis es de origen del felógeno en el ámbito epidérmico. Los cotiledones y eófilos son hojas dorsiventrales, con un estrato de parénquima en empalizada y algunas capas de parénquima esponjoso. Los cotiledones tienen un haz vascular colateral en la vena media, mientras en los eófilos el haz es bicolateral.
Tabernaemontana catharinensis is a species belonging to the family Apocynaceae. In this paper, the seedling morphology and anatomy of this species are described and discussed. The seedling development was analyzed until the first eophyll pairs formation. The seeds were collected from several trees, in fragments of the semideciduous seasonal alluvial and submontaneforest located on the Upper Paraná River floodplain. The seeds were germinated at constant temperatures of 300C, using germination chambers and maintained under continuous fluorescent light. Seedlings development occurred in the greenhouse. The seedlings fixed in FAA 50 were sectioned by microtome and stained with safranin and astra blue. Seedling is phanerocotylar and epigeal with axial root, collet, ovate cotyledons, reduced epicotyl, and lanceolate eophylls similar to the metaphylls. Root is tetrarch. Hypocotyl and epicotyl have stem structure, and they present secondary growth with phellogen of epidermic origin. Cotyledons and eophylls are dorsiventral leaves, with uniseriate palisade parenchyma and some layers of spongy parenchyma. Cotyledons have a collateral vascular bundle in the midrib, while in the eophylls is bicollateral one.
Subject(s)
Apocynaceae/anatomy & histology , Apocynaceae/growth & development , Germination , Greenhouses/methods , Tabernaemontana/anatomy & histology , Tabernaemontana/growth & development , BotanyABSTRACT
Celtis iguanaea es una especie pionera de la vegetación rebaliera. Las plantas de esta especie que ocurren en la planicie de inundación, con el eófilo completamente extendido, fueron sometidas a los siguientes tratamientos: capacidad de campo, anegadas por 25, 50 y 75 días y sumergidas por 25 y 50 días. Se constató que el anegamiento y la sumersión inhiben el crecimiento de las plantas causando una disminución de la materia seca de la parte aérea y la raíz. Plantas hundidas también presentaron abscisión foliar, degeneración del sistema radicular y un proceso precoz de senescencia. Después de 50 días de sumersión, todas las plantas murieron. Las plantas anegadas y sumergidas presentaron crecimiento secundario reducido de la raíz, hipocótilo y epicótilo. Las plantas anegadas por 75 días presentaron lenticelas y mayor número de pelos absorbentes. Los cotiledones y eófilo de las plantas anegadas y sumergidas no presentaron alteraciones anatómicas evidentes. El porcentaje de espacios intercelulares tampoco fue alterado. Celtis iguanaea, al presentar algunos caracteres que posiblemente se adapten a las condiciones de saturación hídrica del suelo, puede ser considerada como planta intolerante del anegamiento y la sumersión por un largo período.
Celtis iguanaea is a pioneer species of ciliary forest. In order to elucidate aspects of tolerance to the flooding andthe submersion, plants were submitted to the following treatments: field capacity, flooded for 25, 50 and 75 days and submerged by 25 and 50 days. It was verified that the flooding and the submersion inhibit the growth of the plants (decrease of the dry weight of the aerial part and root). Plants submerged also presented chlorosis, leaf abscission, degeneration of the root system and precocious senescence. After 50 days of submersion, all the plants died. Submerged and flooded plants presented reduced secondary growth of the root, hipocotyl and epicotyl. Flooded plants for 75 days presented lenticels and larger number of absorbent hairs. Cotyledons and eophylls of the flooded and submerged plants did not present evident anatomical alterations. Percentage of intercellular spaces in the root cortex was also not altered. Celtis iguanaea can be considered as intolerant plant to the flooding and the submersion, for long period.
Subject(s)
Cell Nucleus Shape/physiology , Ulmaceae/anatomy & histology , Ulmaceae/chemistry , BotanyABSTRACT
Celtis iguanaea it is a typical arboreal species of ciliar forest, belonging to the family Ulmaceae. This work intends to investigate the morphology and anatomy of seedling species. The seeds used were collected from several trees, in fragments of the Semideciduous Seasonal Alluvial and Submontane Forest located on Upper Paraná River floodplain. The seeds were germinated at constant temperatures (30ºC), using germination chambers and kept under continuous fluorescent light. Seedling development occurred in a greenhouse. Anatomical analysis was made in seedlings fixed in FAA 50. The botanical material was sectioned by microtome and stained with safranin and astra blue. The seedling is phanerocotylar and epigeal, presents ramified root, developed hypocotyl, obovate and persistent cotyledons, green and hairy epicotyl and the first leaf in a shape oblong or lanceolate. Root is tetrarch or diarch. Hypocotyl has secondary growth with deep-origin periderm. Epicotyl also shows secondary growth with periderm of subepidermic origin. Cotyledons and eophyll are dorsiventral leaves with cystolith
Celtis iguanaea é uma espécie pioneira, típica de mata ciliar. O presente estudo visa a investigação da morfoanatomia da plântula dessa espécie, pertencente à Ulmaceae. As sementes, coletadas na planície de inundação do alto rio Paraná, foram germinadas em câmara de germinação com temperatura constante de 30ºC e mantidas sob luz fluorescente contínua. O desenvolvimento das plântulas ocorreu em casa de vegetação. A análise anatômica foi feita em plântulas fixadas em FAA 50. Esse material foi secionado transversalmente e as seções obtidas foram coradas em safranina e azul de astra. Verificou-se que a plântula é fanerocotiledonar, epigéia, e apresenta raiz ramificada, hipocótilo desenvolvido, cotilédones obovados e persistentes, epicótilo verde e piloso e eofilo oblongo ou lanceolado. A raiz é tetrarca ou diarca. O hipocótilo possui crescimento secundário com periderme de origem profunda. O epicótilo também apresenta crescimento secundário com periderme de origem subepidérmica. Os cotilédones e o eofilo são folhas dorsiventrais com cistólitos