Efecto del choque térmico en la germinación y establecimiento temprano de cinco especies de leguminosas de un bosque seco tropical
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El fuego es un disturbio natural o antrópico presente en diferentes ecosistemas del mundo. Como respuesta a este disturbio, las plantas han generado rasgos que les permiten bien sea resistir o reponerse a los eventos de fuego. Entre estos rasgos se destaca la capacidad de germinación de las semillas al ser expuestas a derivados del fuego como el calor, el humo o las cenizas. Aunque en los bosques secos tropicales de Colombia este disturbio es considerado como una amenaza, muy poco se conoce sobre la capacidad de germinación post-fuego de la vegetación. Una de las familias de plantas que posee una persistencia generalizada a incendios, particularmente mediante la germinación estimulada por fuego son las Leguminosas, la cual es altamente dominante en estos ecosistemas. Así, el objetivo de esta investigación fue evaluar el efecto del calor en la germinación y establecimiento temprano de semillas de cinco especies de leguminosas: Albizia niopoides, Piptadenia cf. uliginosa, Pseudosamanea guachapele, Chloroleucon mangense y Enterolobium cyclocarpum.
Con el fin de cumplir con este propósito, se recolectaron semillas de cada especie y se expusieron a nueve tratamientos, producto de la combinación de tres temperaturas (i.e. 80°C, 100°C y 140°C) y tiempos de exposición (i.e 1, 3 y 5 minutos). Posterior a la exposición, las semillas fueron puestas a germinar en cajas Petri con papel filtro humedecido durante los siguientes dos meses. Las semillas germinadas se trasplantaron en bandejas de maduración para evaluar su supervivencia. Así mismo, se evaluó la viabilidad de las semillas no germinadas con test de tetrazolio. Los resultados muestran que las semillas de Albizia niopoides (especie de semillas pequeñas) y Piptadenia cf. uliginosa (de semillas medianas) son sensibles al calor y no toleraron temperaturas mayores a 100°C por un minuto. Pseudosamanea guachapele, Chloroleucon mangense y Enterolobium cyclocarpum (de diferentes tamaños seminales) se consideraron especies tolerantes al calor, ya que germinaron en casi todos los tratamientos y presentaron altos niveles de viabilidad después de ser expuestas a los choques térmicos.
De manera general, es posible afirmar que las especies sensibles al calor pueden perder sus poblaciones ante eventos de fuegos recurrentes, mientras que las tolerantes requieren del calor para poder reclutar y puedan permanecer con más éxito en el banco de semillas. Finalmente, el peso de las semillas no influye en la tolerancia al calor.
Fire is a natural or anthropic disturbance present in different ecosystems around the world. In response to this disturbance, plants have generated traits that allow them to either resist or recover from fire events. Among these traits, the germination capacity of the seeds stands out when exposed to derivatives of fire such as heat, smoke or ashes. Although in the tropical dry forests of Colombia this disturbance is considered a threat, very little is known about the post-fire germination capacity of the vegetation. One of the families of plants that has a generalized persistence to fires, particularly through fire-stimulated germination, are Legumes, which is highly dominant in these ecosystems. Thus, the objective of this research was to evaluate the effect of heat on the germination and early establishment of seeds of five species of legumes: Albizia niopoides, Piptadenia cf. uliginosa, Pseudosamanea guachapele, Chloroleucon mangense and Enterolobium cyclocarpum. In order to fulfill this purpose, seeds of each species were collected and exposed to nine treatments, product of the combination of three temperatures (ie 80 ° C, 100 ° C and 140 ° C) and exposure times (ie 1 , 3 and 5 minutes). After exposure, the seeds were put to germinate in Petri dishes with moistened filter paper for the next two months. The germinated seeds were transplanted into ripening trays to evaluate their survival. Likewise, the viability of ungerminated seeds was evaluated with a tetrazolium test. The results show that the seeds of Albizia niopoides (small-seeded species) and Piptadenia cf. uliginosa (medium-sized seeds) are sensitive to heat and did not tolerate temperatures above 100 ° C for one minute. Pseudosamanea guachapele, Chloroleucon mangense and Enterolobium cyclocarpum (of different seminal sizes) were considered heat-tolerant species, since they germinated in almost all treatments and presented high levels of viability after being exposed to thermal shocks.In general, it is possible to affirm that heat-sensitive species can lose their populations to recurrent fire events, while tolerant species require heat to be able to recruit and to remain more successfully in the seed bank. Finally, the weight of the seeds does not influence heat tolerance.
Fire is a natural or anthropic disturbance present in different ecosystems around the world. In response to this disturbance, plants have generated traits that allow them to either resist or recover from fire events. Among these traits, the germination capacity of the seeds stands out when exposed to derivatives of fire such as heat, smoke or ashes. Although in the tropical dry forests of Colombia this disturbance is considered a threat, very little is known about the post-fire germination capacity of the vegetation. One of the families of plants that has a generalized persistence to fires, particularly through fire-stimulated germination, are Legumes, which is highly dominant in these ecosystems. Thus, the objective of this research was to evaluate the effect of heat on the germination and early establishment of seeds of five species of legumes: Albizia niopoides, Piptadenia cf. uliginosa, Pseudosamanea guachapele, Chloroleucon mangense and Enterolobium cyclocarpum. In order to fulfill this purpose, seeds of each species were collected and exposed to nine treatments, product of the combination of three temperatures (ie 80 ° C, 100 ° C and 140 ° C) and exposure times (ie 1 , 3 and 5 minutes). After exposure, the seeds were put to germinate in Petri dishes with moistened filter paper for the next two months. The germinated seeds were transplanted into ripening trays to evaluate their survival. Likewise, the viability of ungerminated seeds was evaluated with a tetrazolium test. The results show that the seeds of Albizia niopoides (small-seeded species) and Piptadenia cf. uliginosa (medium-sized seeds) are sensitive to heat and did not tolerate temperatures above 100 ° C for one minute. Pseudosamanea guachapele, Chloroleucon mangense and Enterolobium cyclocarpum (of different seminal sizes) were considered heat-tolerant species, since they germinated in almost all treatments and presented high levels of viability after being exposed to thermal shocks.In general, it is possible to affirm that heat-sensitive species can lose their populations to recurrent fire events, while tolerant species require heat to be able to recruit and to remain more successfully in the seed bank. Finally, the weight of the seeds does not influence heat tolerance.
Palabras clave
Fuego, Choque térmico, Calor, Leguminosas, Semillas, Maestría en Manejo, Uso y Conservación del Bosque - Tesis y disertaciones académicas, Germinación - Control de temperatura, Fisiología vegetal - Colombia, Leguminosas - Especies - Colombia, Bosques tropicales - Colombia, Fire, Heat shock, Legumes, Seeds