Variación morfológica del labelo de Vanilla pompona (Orchidaceae) en Oaxaca, México

Abstract

ResumenEn orquídeas, la forma y tamaño de caracteres florales como el labelo, sirve para clasificar variación dentro y entre especies. El objetivo del presente trabajo fue caracterizar la variación morfológica infraespecífica a través del labelo de Vanilla pompona analizando 80 flores provenientes de 23 ejemplares del estado de Oaxaca, México. El labelo de cada flor se diseccionó y analizó mediante su morfometría geométrica, obteniéndose 60 variables que se agruparon en región basal, media y apical. Se realizó un análisis de varianza que consideró las recolectas como fuentes de variación y 2 análisis multivariados, componentes principales y conglomerados. Entre recolectas, 58 variables analizadas fueron estadísticamente significativas. El modelo explicó 81% de la variación total estudiada con los 3 primeros componentes principales. Existe variación morfológica floral del labelo en Vanilla pompona representado por 4 morfotipos en Oaxaca, resultado de la probable presión y selección por parte de los polinizadores y el ambiente, donde los complejos montañosos posiblemente han coadyuvado como barrera geográfica.

Vanilla pompona Schiede (Vanilloideae-Orchidaceae): Morphological Variation of the Labellum in the Mexican Localities of Veracruz, Puebla, Jalisco and Oaxaca

“…Each 150 mL recipient contained a preservative solution of ethanol (50%), lactic acid (4%), benzoic acid (0.5%, glycerin (2.5%) and distilled water (43%). The recipients were stored at room temperature (23-24 • C) in a dark room [17,22]. The collected flowers were stored in a preservative solution.…”

“…For the genus Vanilla, flowers are used to differentiate leafless species in the Southwestern Indian Ocean region, considering differences in the shape of the labellum [20]. Infraspecific variation has also been evaluated by characterizing the labellum shape of species such as V. planifolia [21] and V. pompona [22]. In the Mesoamerican region, V. planifolia variation is identified by four morphotypes in Oaxaca [23], four morphotypes in the San Luis Potosí Huastec region, Mexico [21], and five morphotypes in the Hidalgo Huastec region, Mexico [24].…”

“…For V. pompona, floral morphological variation of the labellum is still being studied; to date, there is only one study that reports four morphotypes in collections from localities in Oaxaca. This variation is explained by the constant selection pressure exerted by pollinators together with the environment [22].…”

“…Knowledge and understanding of the variation within species are vital for the conservation of ecosystems and the social and cultural wellbeing of man [27,28]. Recently, studies were conducted to determine genetic variation [29][30][31] and floral morphological variation [21][22][23]26] of the most used Vanilla species, in a search for different stable populations that would increase genetic variation [31]. However, for V. pompona, detailed information on genotypes and phenotypes that make up the primary genetic pool and its interaction with the environment is limited.…”

“…The evaluation includes the morphological variation of Pseudolaelia vellozicola Hoehne populations [38] and populations of Pseudorchis straminea Fernald and P. albida Á.Love and D.Love [39]. In addition to studies on morphological variation in species of the Vanilla genus [21][22][23][24], studies of the labellum variation can be related with biotic factors (pollinators) and abiotic factors (environment). In orchids, biotic and abiotic factors, such as temperature and light, have been reported to influence the flowering period [40,41].…”