RÉSUMÉ
El objetivo del estudio fue evaluar la germinación de las semillas de cinco especies forestales nativas de Córdoba: Cedrela odorata, Cariniana pyriformis, Bombacopsis quinata, Anacardium excelsum y Schizolobium parahybum. El estudio, se realizó entre abril de 2013 y mayo de 2014, en el Laboratorio de fitomejoramiento de la Universidad de Córdoba. En cada uno de los dos ambientes de germinación: cámara germinativa y casa- malla, se utilizó un diseño completamente al azar, con cinco especies forestales como tratamientos y cuatro repeticiones de 50 semillas cada una. Toda la semilla fue sumergida en agua destilada, a temperatura ambiente de 27°C, por 24 horas, antes de la siembra. Se estimaron y compararon las variables, porcentaje de germinación (PG), índice de velocidad de germinación (IVG), germinación diaria media (GDM), valor pico (VP) y valor de germinación (VG). Los resultados mostraron diferencias estadísticas entre especies e interacción especies por ambientes de germinación en el análisis combinado de varianza, para los parámetros fisiológicos de la germinación evaluados, a excepción del PG. Los valores de los parámetros de germinación fueron mayores en cámara de germinación, con incrementos entre el 48,2 y 124,2%, en GDM y VG, respectivamente. A excelsum mostró las mayores diferencias entre especies en los dos ambientes de germinación en todos los parámetros germinativos, mientras que B quinata presentó las menores diferencias. Se recomienda estimar los parámetros de germinación en cámara germinativa, en lugar de casa-malla, siempre que se disponga de este equipo.
The objective of this study was to evaluate the germination of seeds of five native forest species of Córdoba: Cedrela odorota, Cariniana pyriformis, Bombacopsis quinata, Anacardium excelsum and Schizolobium parahybum. The study was conducted between April of 2013 and May of 2014 at the Laboratory of Plant Breeding at the Universidad de Córdoba. A completely randomized design was used in each environment: germination chamber and greenhouse with five forest species as treatments and four replicates of 50 seeds each. All seeds were immersed in distilled water at room temperature of 27°C for 24 hours before planting. The parameters germination percentage (GP), germination speed index (GSI), mean daily germination (MDG), peak value (PV) and germination value (GV) were estimated and compared. The results showed statistical differences between species and interaction species x germination environments in combined analysis of variance for germination physiological parameters evaluated, except for PG. The values of germination parameter estimated were higher in germination chamber, with increases between 48.2% and 124.2% in MDG and GV, respectively. A excelsum showed the greatest differences between species in two germination environments in all parameters estimated, while B quinata showed minor differences. It is recommended to estimate the parameters in germination chambers, instead of greenhouse, whenever this equipment is available.
RÉSUMÉ
Kielmeyera coriacea Mart. (Clusiaceae), popularly known as "pau-santo", is a typical Brazilian cerrado tree known due to its varied secondary metabolites. This study aimed to determine the allelopathic potential of the hydroalcoholic extract of leaves of K. coriacea through bioassays of seed germination, seedling growth and mitotic index of Lactuca sativa L. (lettuce). In addition it was done the tetrazolium assay and a phytochemical screening. The extract concentrations caused alterations in germination parameters, in root growth and in the mitotic index. The phytochemical screening showed the presence of triterpenes, coumarins, steroids, flavonoids and condensed tannins, compounds known to confer allelopathic characteristics upon other species. These data indicate that K. coriacea presents an allelopathic potential because its leaf extracts interfere with germination and growth without any interference of pH and osmotic potential in the results.
Kielmeyera coriacea Mart. (Clusiaceae), conhecida popularmente como "pau-santo", é uma árvore típica do cerrado brasileiro, conhecida pelos seus variados metabólitos secundários. O estudo teve como objetivo determinar o potencial alelopático do extrato hidroalcoólico de folhas de K. coriacea por meio dos bioensaios de germinação, crescimento de plântulas e índice mitótico de Lactuca sativa L. (alface). Além disso, foi feito o teste de tetrazólio e uma triagem fitoquímica. As concentrações de extrato causaram alterações nos parâmetros de germinação, no crescimento radicular e no índice mitótico. A triagem fitoquímica mostrou a presença de triterpenos, cumarinas, esteroides, flavonoides e taninos condensados, compostos conhecidos por conferir características alelopáticas sobre outras espécies. Estes dados indicam que K. coriacea apresenta potencial alelopático pois o extrato de sua folha interfere na germinação e no crescimento da planta alvo, sem qualquer interferência do pH e do potencial osmótico.