Functional morphology of two Lepismium species (Rhipsalideae, Cactaceae) Morfología funcional de dos especies de Lepismium (Rhipsalideae, Cactaceae)

María Regina Torres-Boeger, Patricia Soffiatti, Marco Antônio Gomes-Souto, Márcia Budchen, Katiane Paula Bagatini, Manuela Dal Forno
2010 Revista Mexicana de Biodiversidad  
The morphology and anatomy of stem segments of 2 species of Lepismium (Cactaceae), which grow naturally in the Araucaria forest understory, in the state of Paraná, Brazil, are compared. The goal of this study was to identify morphological traits adapted to epiphytism and to the low light condition of the studied environment. Twenty-five segments of Lepismium cruciforme and L. lumbricoides were collected and various morphological and anatomical features were measured. Differences (p < 0.05) were
more » ... ces (p < 0.05) were found between the species in mean values for total volume, total photosynthetic area, epidermis and hypodermis thickness, sclerenchyma area/total transversal area proportion of the stem segments and parenchyma area/total transversal area proportion, which can be correlated to their differences in shape. The xeric features found in Lepismium, most of them typical of drought-adapted cacti, have allowed the development of the epiphytic habit and the occupation of humid forests. As epiphytes, they are subject to some extent to water scarcity, although not to severe conditions such as most terrestrial cacti. Mean values for hypodermis thickness, water content, amount of sclerenchyma and stomatal densities are more similar to mesomorphic plants, and can be correlated to epiphytism, showing that these species have lost some of their adaptations to dry environments.Se compara la morfología y la anatomía de los segmentos del tallo de 2 especies de Lepismium, que crecen naturalmente en el sotobosque del bosque de Araucaria, en el estado de Paraná. El objetivo de este estudio fue identificar rasgos morfológicos de adaptación para el epifitismo y para condiciones de poca luz del ambiente estudiado. Se recolectaron 25 ejemplares de L. cruciforme y de L. lumbricoides y se midieron rasgos tanto morfológicos como anatómicos de los tallos. Se encontraron diferencias (p < 0.05) entre las especies considerando los valores promedio del volumen total, del área total fotosintética, del grosor de la epidermis y de la hipodermis, del área del [...]
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