Sincronía reproductiva interpoblacional de Agave cocui (Agavaceae) en Venezuela

Interpopulation reproductive synchrony of Agave cocui (Agavaceae) in Venezuela. Agave cocui (Agavaceae) is a species with broad distribution in arid and semiarid areas of Venezuela and Colombia. Despite of its ecological importance as a source of food for wildlife, and its economic value for production of a spirit drink, studies on the reproductive ecology of the species are relatively rare. In this study, we conducted a oneyear evaluation of the flowering and fruiting phenology of A. cocui in the eight representative localities of the species’ distribution in Venezuela. Within each study site, we chose an area with a minimum of 50 reproductive individuals and followed their reproductive phenophases with the help of binoculars, using six qualitative cathegories (emerging reproductive stalk, flowers, inmature fruits, mature fruits, bulbils and dry stalk) every two months. Emergence of the reproductive stalk in most of the examined populations began in September (rainy season), although this event delayed two months in a few populations. We detected significant negative correlations between precipitation and the percentage of flowering occurrence in four of the eight populations. Floral resources are available for flower visitors during approximately five months of the year (January-May). In most populations production of flowers initiated in January (dry season), and for Western Venezuela and Andean regions, the flowering main peak occurred in January. Localities from the Central and Eastern Coast exhibited the flowering peak in March, showing a delay of approximately two months with respect to other populations. Beginning of fruit set varied among localities from January to May; however, peak production of mature fruits concentrated in May, and fruit occurrence varied broadly between 5.2 and 85%. Bulbil production was detected in all populations and varied greatly among them (maximum percentage per population: 26.19-92.10%). High flowering synchronicity (Phenophase Overlapping Index: 0.756 and 0.999) was observed among all populations monitored in Western Venezuela, including the Andean localities. This condition might facilitate the existence of a nectar corridor from the Western Coast and nearby islands, to the Andean arid patches, which could be potentially used by nectar-feeding bats and birds dependent on agave flowers during part of the year. Rev. Biol. Trop. 59 (3): 1359-1370. Epub 2011 September 01.

cocui (Agavaceae) es una especie de amplia distribución en zonas áridas y semiáridas de Venezuela y Colombia. A pesar de su importancia ecológica como fuente de recursos para la fauna silvestre y de su potencial valor económico como materia prima para la producción del licor “Cocuy de Penca”, los estudios sobre su ecología reproductiva son muy escasos. En este estudio se evaluó la fenología de floración y fructificación de A. cocui en ocho localidades de Venezuela. La fase reproductiva se inició al finalizar el periodo de lluvias. Las flores se producen durante cinco meses. Para la Región Noroccidental del país y los Andes los máximos de floración ocurrieron en enero, mientras que las localidades en la costa central y oriental exhibieron un desface de cerca de dos meses, a principios de marzo. La mayor sincronía floral ocurrió entre todas las poblaciones censadas en el occidente del país, incluyendo las localidades andinas. Dicha sincronía reproductiva potenciaría la conformación de un corredor de néctar para aves y murciélagos, que se extendería desde el Norte de Falcón, en la Costa Occidental, hasta los bolsones andinos, en el Suroeste del país.

Pulpa del fruto del cardón dato (Stenocereus griseus, Cactaceae) como materia prima para la elaboración de mermelada / Cardon dato (Stenocereus griseus, Cactaceae) fruit pulp as raw material for marmalade production

El presente trabajo de investigación se evaluó la posibilidad de elaborar mermeladas a partir de la pulpa de los frutos de cardón dato (Stenocereus griseus) de las variedades Blanca y Roja. Para ello, se propuso desarrollar las formulaciones de dichas mermeladas y estudiar su estabilidad durante tres meses de almacenamiento a temperatura ambiente. Como primer paso se caracterizaron los frutos de ambas variedades, observándose que a pesar de la diferencia notable de color entre ambos, no hay diferencias estadísticamente significativas en su peso promedio, dimensiones y proporciones de pulpa, piel y semillas. Por otro lado, ambas pulpas presentaron valores altos de pH (5,2 en ambas variedades) y contenidos bajos de azúcares reductores (3,59 g/100g variedad Blanca y 2,23 g/100g variedad Roja), azúcares no reductores (0,75 g/100g variedad Blanca y 2,03 g/100g variedad Roja), pectina (0,14 g/100g variedad Blanca y 0,23 g/100g variedad Roja) y ácidos (7,67 g/100g variedad Blanca y 0,15 g/100g variedad Roja), debido a lo cual fue necesario añadir azúcar, pectina y ácido cítrico a la formulación de la mermelada. La primeras mermeladas elaboradas presentaron consistencia gomosa, lo cual se solucionó añadiendo el ácido desde el principio del proceso de elaboración en lugar de al final. Durante los tres meses de almacenamiento, las mermeladas tuvieron buena aceptación por parte de los panelistas, a pesar de ligeras fluctuaciones observadas durante el almacenamiento en el pH y contenidos de sólidos solubles y acidez total titulable.

This study aimed to examine the possibility of producing marmalades from the fruit pulp of the red and white varieties of cardón dato (Stenocereus griseus). We developed the formulations of the marmalades and evaluated their stability during three months of storage at room temperature. As first step, we characterized the fruits of the two color varieties, observing that despite the considerable difference between both color varieties, there were no significant differences in average weight, dimensions and proportion of pulp, skin and seeds. The pulp of the two color types had high pH (5,2) values and low contents of reductor sugars (3,59 g/100g white variety 2,23 g/100g red variety), non reductor sugars (0,75 g/100g white variety and 2,03 g/100g red variety), pectin (0,14 g/100g white variety and 0,23 g/100g red variety) and acids (7,67 g/100g white variety and 0,15 g/100g red variety). It is needed to include sugar, pectin, and citric acid in the marmalade formula. The first marmalades produced were gummy, a problem that we solved adding the acid from the beginning of the making process. During the three months of storage, the marmalades had good acceptance by the evaluators, this despite slight fluctuations observed in pH, solid contents, and acidity.