Biología de la polinización de Oplonia nannophylla (Urban) Stearn (Acanthaceae)
Fecha
2017-07-05
Autores
Reaño Jiménez, Claudia
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Editor
Universidad Central “Marta Abreu “ de Las Villas. Facultad de Ciencias Agropecuarias. Departamento de Biología
Resumen
Oplonia nannophylla es una especie endémica de Cuba que presenta un sistema reproductivo poco
común, pues sus flores son heterostilas y zigomorfas. Se ha planteado que la heterostilia sería de poca
utilidad en flores zigomorfas, pues estas ya están adaptadas para la polinización cruzada. Por tanto, es
interesante la existencia de estos dos mecanismos tan diferentes para favorecer este fenómeno. Se
propuso determinar el posible efecto de la zigomorfía y la heterostilia en el éxito reproductivo de esta
especie. Para ello se caracterizó la biología floral, analizó el sistema reproductivo y describió la ecología
de la polinización. Para determinar el grado de zigomorfía se utilizaron técnicas de morfometría
geométrica. Se plantea un nuevo índice, que permite por primera vez determinar el grado de
reciprocidad de pistilos y estambres de cada individuo, con respecto al resto de los individuos del morfo
opuesto en la población. No se encontraron diferencias en las variables morfométricas y en la
producción de polen entre los morfos, por lo que no existe polimorfismo en los caracteres ancilares.
Además, carece de sistema de incompatibilidad heteromórfico, lo que pudiera representar una ventaja
adaptativa. La pequeña presentación floral y las bajas producciones de néctar, así como los efectos
antrópicos en las localidades estudiadas, pudieran ser la causa de las bajas tasas de visitas. No se
encontró relación estadísticamente significativa del grado de reciprocidad y la zigomorfía con el éxito
reproductivo, debido a las bajas tasas de visita de los polinizadores en las localidades estudiadas
Oplonia nannophylla is a Cuban endemic species that presents an atypical reproductive system, because its flowers are heterostylous and zygomorphic. It has been suggested that heterostyly would be useless in zygomorphic flowers, as they are already adapted for cross-pollination. Therefore, it is interesting the existence of these two mechanisms so different to favor this phenomenon. It was proposed to determine the possible effect of zygomorphy and heterostyly on the reproductive success of this species. For this purpose, the floral biology was characterized, analyzed the reproductive system and described the ecology of the pollination. To determine the degree of zygomorphism, geometric morphometry techniques were used. A new index is proposed, which allows for the first time to determine the reciprocity degree of pistils and stamens of each individual, with respect to the rest of the individuals of the opposite morph in the population. No differences were found in the morphometric variables and in the pollen production among the morphs, so there is no polymorphism in the ancillary characters. In addition, it lacks a system of heteromorphic incompatibility, which could represent an adaptive advantage. The small floral display and the low yields of nectar, as well as the anthropic effects in the studied localities, could be the cause of the low rates of visits. There was no statistically significant relationship of the reciprocity degree and zygomorphy with the reproductive success, due to the low visitation rates of pollinators in the studied localities.
Oplonia nannophylla is a Cuban endemic species that presents an atypical reproductive system, because its flowers are heterostylous and zygomorphic. It has been suggested that heterostyly would be useless in zygomorphic flowers, as they are already adapted for cross-pollination. Therefore, it is interesting the existence of these two mechanisms so different to favor this phenomenon. It was proposed to determine the possible effect of zygomorphy and heterostyly on the reproductive success of this species. For this purpose, the floral biology was characterized, analyzed the reproductive system and described the ecology of the pollination. To determine the degree of zygomorphism, geometric morphometry techniques were used. A new index is proposed, which allows for the first time to determine the reciprocity degree of pistils and stamens of each individual, with respect to the rest of the individuals of the opposite morph in the population. No differences were found in the morphometric variables and in the pollen production among the morphs, so there is no polymorphism in the ancillary characters. In addition, it lacks a system of heteromorphic incompatibility, which could represent an adaptive advantage. The small floral display and the low yields of nectar, as well as the anthropic effects in the studied localities, could be the cause of the low rates of visits. There was no statistically significant relationship of the reciprocity degree and zygomorphy with the reproductive success, due to the low visitation rates of pollinators in the studied localities.
Descripción
Palabras clave
Heterostilia, Oplonia nannophylla, Zigomorfía, Polinización