ABSTRACT
RESUMEN Amaranthus hybridus L., conocido como bledo, es una planta maleza en una gran variedad de cultivos en el mundo, que se caracteriza por producir alto número de semillas latentes. Para generar estrategias de manejo sostenibles en esta especie es necesario comprender mejor la fisiología de sus semillas. Por tanto, el objetivo fue evaluar el efecto de la luz, de las giberelinas y la profundidad de la siembra sobre la germinación de semillas de bledo. En un primer experimento, se evaluaron cuatro tratamientos de luz (rojo, azul, sin luz y luz natural «testigo¼); en el segundo, se imbibieron semillas en diferentes concentraciones de ácido giberélico (0, 200, 400 y 800mg L-1 de GA3) y, en un último experimento, se evaluaron ocho profundidades de siembra (10, 20, 30, 40, 50, 60, 70 y 80mm), utilizando turba como sustrato. Se encontró mayor porcentaje de germinación en oscuridad, indicando que son semillas fotoblásticas negativas. Para el experimento de giberelinas, el mejor resultado se obtuvo con 400 y 800mg L-1 de ácido giberélico. En el tercer experimento, se observó alto porcentaje de emergencia de plántulas en las primeras profundidades (10mm a 30mm); a mayor profundidad hubo menor emergencia. La respuesta diferencial a la luz, a la aplicación de las giberelinas y el alto porcentaje de semillas viables que no germinaron permite concluir que semillas de bledo poseen latencia fisiológica.
ABSTRACT Amaranthus hybridus L., known as bledo, is a weed in a wide variety of crops worldwide, characterized by producing high number of seeds with dormancy. To generate sustainable management strategies of this species, it is necessary to better understand the physiology of its seeds. Therefore, the objective was to evaluate the effect of light, gibberellins, and seed burying depth on seed germination of bledo. In the first experiment, four light conditions were evaluated (red, blue, without light and natural light (control)), in the second experiment the seeds were imbibed in different concentrations of gibberellic acid (0, 200, 400 and 800mg L-1 of GA3), and in the last experiment, 8 planting depths were evaluated (10, 20, 30, 40, 50, 60, 70 or 80mm) using peat as a substrate. A higher percentage of seed germination in darkness was found, indicating that this species had negative photoblastic seeds. For the gibberellin experiment, the best result was obtained with treatment with 400 and 800mg L-1 of gibberellic acid. In the third experiment, a high percentage of seedling emergence was observed from the first depths (10mm to 30mm); the greater was the depth, the less emergence was found. The differential responses to light, the application of gibberellins, and the high percentage of non-germinated viable seeds allowed to conclude that bledo seeds possess physiological dormancy.
ABSTRACT
Minthostachys mollis (Kunth) Griseb., es un arbusto perenne que crece en la región andina de Colombia; es ampliamente utilizada por las comunidades rurales donde es valorado por sus propiedades medicinales. El objetivo de este estudio fue determinar el efecto de la luz (luz roja, luz blanca y luz natural) y del ácido giberélico (0, 5, 15, 25 ppm) en el proceso de germinación de M. mollis. Se encontró inhibición de la germinación bajo condiciones de oscuridad. No se observó efecto de AG3 sobre la germinación. Los porcentajes de germinación fueron superiores a 80% para los tratamientos con luz (semilla fotoblástica positiva), donde el tratamiento con luz roja tuvo el efecto más significativo sobre el proceso de germinación.
Minthostachys mollis (Kunth) Griseb., is a perennial shrub that grows in the Andean region of Colombia; this species is widely used by rural communities where it is valued for its medicinal properties. The aim of this study was to determine the effect of light (red light, white light, and natural light) and gibberellic acid (0, 5, 15, 25 ppm) on the process of germination of M. mollis. We found a strong inhibition of germination under conditions of darkness. We do not observe effect of AG3 on germination. The germination percentages obtained were above 80% (positive photoblastic seeds) for the three proposed lighting treatments where red-light treatment had a most significant effect on the germination process.
ABSTRACT
Plantago tomentosa Lam. (Plantaginaceae) é usada na medicina popular como agente anti-tumoral, antimicrobiana e antinflamatória. Sua propagação ocorre por meio de sementes, cuja germinação tem sido pouco investigada. Dessa forma, o presente trabalho teve como objetivo verificar a influência da luz, temperaturas e substratos sobre a porcentagem total de germinação/emergência e índice de velocidade de germinação/emergência. Foram testadas diferentes temperaturas (15, 20, 25, 30 e 35°C constantes e, 15-25°C e 20-30°C alternadas) na ausência e presença de luz constante. Os substratos testados foram areia, terra de subsolo, vermiculita e Plantmax®, além da combinação de terra de subsolo com os demais, na proporção de 1:1. Pelos resultados obtidos, concluiu-se que as sementes de tanchagem apresentam comportamento fotoblástico positivo, independente da temperatura testada. A temperatura alternada de 15-25°C e 15 e 20°C constantes garantem melhor expressão do vigor. O substrato areia é recomendado para o estudo da emergência.
Plantago tomentosa Lam. (Plantaginaceae) is used in the popular medicine as anti-tumoral, antimicrobial and anti-inflammatory agent. This propagation is basically done by seeds, which the publications available are scarce. The objective of this research was to study the influence of the light, temperatures and substrate on the total percentage of germination/emergency and index of germination/emergency speed. There were used different temperatures (15, 20, 25, 30 and 35°C constant and, 15-25°C and 20-30°C alternated) in the absence and presence of constant light. The substrate tested were subsoil sand, land, vermiculite and Plantmax®, besides the subsoil land combination, in the ratio of 1:1. the results suggest that Plantago tomentosa seeds was a positive photoblastic behavior, independent of the tested temperature. The use of constant temperature of 15 and 20°C and alternated (15-25°C) promated a higher vigor expression. The substrate sand is recommended for the emergency study.