Autoecología, biología floral y sistema reproductivo de Ravenia spectabilis subsp. leonis (Vict.) Beurton.
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Fecha
2012-06-27
Autores
Pérez Obregón, Rafael Alejandro
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Editor
Universidad Central ´´Marta Abreu´´ de Las Villas
Resumen
Ravenia spectabilis subsp. leonis (Vict.) Beurton se distribuye en Cuba y la
Española, es un taxón reportado como amenazado para la provincia de Villa
Clara. La falta de estudios específicos relacionados con la autoecología y con
mecanismos de propagación de la especie, dificultan la elaboración de
programas objetivos que contribuyan a la conservación de este taxón, por lo
que el presente trabajo se traza como objetivos diagnosticar las condiciones
ambientales en que se desarrolla; determinar representantes de la flora
asociada a este taxón en su hábitat; caracterizar aspectos de su fenología,
biología floral y evaluar su sistema reproductivo. Para diagnosticar las
condiciones ambientales requeridas por la especie se determinó la cercanía a
las fuentes de agua y se le realizó análisis físico-químico al suelo. La flora
asociada se determinó a partir del establecimiento de parcelas. Los parámetros
fenológicos se siguieron durante un año cuantificándose el número de botones,
flores, (en fase masculina y femenina) y frutos. Se evaluó la biología floral a
través de variables morfológicas, diámetro de la corola y de la apertura del
pseudotubo de la corola y largo del estilo por estado sexual. Para evaluar
sistemas reproductivos se realizaron experimentos relacionados con:
agamospermia, autopolinización expontánea, autogamia, geitonogamia,
xenogamia, suplementación de polen que se contrastó con un grupo control. La
especie se desarrolla sobre un suelo ultramáfico a una distancia media del
agua de 2 m. En su flora asociada destacan 11 endémicos y el 52 % presenta
alguna categoría sinantrópica, esto evidencia la degradación de su hábitat. La
especie presenta una floración larga, casi todo el año, con mayor intensidad en
junio y julio; presenta superposición de fases sexuales y sin sincronismo, esto
puede facilitar la geitonogamia. En la etapa femenina las flores presentan
mayor tamaño; la producción de néctar y concentración de sacarosa es mayor
en la etapa masculina y cuando se somete a extracciones sucesivas se
produce en mayor cantidad y concentración que sin extracción, por lo que se
refuerzan las funciones masculinas y la capacidad de resíntesis garantiza una
oferta constante de néctar lo cual puede repercutir en el número de visitas
florales. La planta no es capaz de reproducirse por partenocarpia ni de
autopolinizarse. Sin embargo, es autogámica y fructifica por geitonogamia y
xenogamia. La intervención de polinizadores es esencial para garantizar su
reproducción y potenciar la variabilidad genética de su descendencia, aspecto
a tener en cuenta para la conservacion de la especie.
Ravenia spectabilis subsp leonis ( Vict.) Beurton is distributed in Cuba and the Spaniard, reported as a threatened taxon for Villa Clara's province. The lack of specific studies related with auto-ecology and with mechanisms of propagation of the species, make the elaboration of objective programs that contribute to the conservation of this taxon difficult, so that the objectives of the present work are: to diagnose the environmental conditions where it develops in; to determine representatives of the flora related to this taxon in its habitat; to characterize its phenology aspects, floral biology and to evaluate its reproductive system. To diagnose the environmental conditions required by the species, the proximity to the water sources was determined in order to accomplish the physical-chemical analysis to the soil. The associated flora was determined according to the establishment of plots of land. Phenologic parameters were followed during a year to quantify the number of buttons, flowers, (in male and female phase ) and fruits. The floral biology through morphologic variables, diameter of the corolla of the opening of the pseudotube of the corolla and length of style for sexual status was evaluated. To evaluate the reproductive systems some experiments were done related to: agamospermy, self-pollination, autogamy, geitonogamy, xenogamy, and suplementation of pollen that it is contrasted with a control group. The species develops on an ultramaphic soil at a half distance of the water, 2 m. In its associated flora stands out 11endemics and the 52% presents synantropic category, that evidences the degradation of its habitat. The species presents a long flowering, almost all year round, with higher intensity in june and july and presents overlap of sexual phases and without synchronism, this can provide the geitonogamy. In the female stage the flowers present bigger size; the production of nectar and concentration of sucrose is bigger in the male stage and when it is subjected to successive extractions it produces in bigger quantity and concentration than without extraction, then they reinforce masculine functions and the capability of re-synthesizes guarantees a constant offer of nectar what influence in the number of floral visits. The plant is not able to reproduce neither for partenocarpy nor for auto-pollination. However, it is autogamic and it bears fruit for geitonogamy and xenogamy. The intervention of pollination agents is essential to guarantee reproduction and to increase the genetic variability of the descendants, aspect to take into consideration for the conservation of the species.
Ravenia spectabilis subsp leonis ( Vict.) Beurton is distributed in Cuba and the Spaniard, reported as a threatened taxon for Villa Clara's province. The lack of specific studies related with auto-ecology and with mechanisms of propagation of the species, make the elaboration of objective programs that contribute to the conservation of this taxon difficult, so that the objectives of the present work are: to diagnose the environmental conditions where it develops in; to determine representatives of the flora related to this taxon in its habitat; to characterize its phenology aspects, floral biology and to evaluate its reproductive system. To diagnose the environmental conditions required by the species, the proximity to the water sources was determined in order to accomplish the physical-chemical analysis to the soil. The associated flora was determined according to the establishment of plots of land. Phenologic parameters were followed during a year to quantify the number of buttons, flowers, (in male and female phase ) and fruits. The floral biology through morphologic variables, diameter of the corolla of the opening of the pseudotube of the corolla and length of style for sexual status was evaluated. To evaluate the reproductive systems some experiments were done related to: agamospermy, self-pollination, autogamy, geitonogamy, xenogamy, and suplementation of pollen that it is contrasted with a control group. The species develops on an ultramaphic soil at a half distance of the water, 2 m. In its associated flora stands out 11endemics and the 52% presents synantropic category, that evidences the degradation of its habitat. The species presents a long flowering, almost all year round, with higher intensity in june and july and presents overlap of sexual phases and without synchronism, this can provide the geitonogamy. In the female stage the flowers present bigger size; the production of nectar and concentration of sucrose is bigger in the male stage and when it is subjected to successive extractions it produces in bigger quantity and concentration than without extraction, then they reinforce masculine functions and the capability of re-synthesizes guarantees a constant offer of nectar what influence in the number of floral visits. The plant is not able to reproduce neither for partenocarpy nor for auto-pollination. However, it is autogamic and it bears fruit for geitonogamy and xenogamy. The intervention of pollination agents is essential to guarantee reproduction and to increase the genetic variability of the descendants, aspect to take into consideration for the conservation of the species.
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Palabras clave
Autoecología, Fenología, Sistema Reproductivo, Flora