Cantidad mínima de lluvia que induce la germinación en un semidesierto andino, la Prepuna (Potosí, Bolivia)
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Ecología en Bolivia
Abstract
Llevé a cabo experimentos de germinación para determinar la cantidad mínima de agua que suscita la germinación (umbral de respuesta) del banco de semillas persistente de un semidesierto andino con lluvias estivales, la Prepuna, y también para conocer la respuesta de las semillas a diferentes niveles de precipitación simulada, todo ello en el ámbito de las teorías sobre el comportamiento de la reserva de semillas en ambientes áridos y semiáridos. Los experimentos fueron efectuados en pequeñas macetas que distribuí en un diseño de bloques aleatorizados. Hubo seis tratamientos de riego: 0 (control), 15, 25, 40, 80 y 160 mm, que se adicionaron de manera acumulativa (dosis de 5 mm). El umbral de respuesta detectado fue de 40 mm. Los riegos superiores al umbral de germinación no produjeron resultados significativamente diferentes de los observados con 40 mm, lo que apunta a que la fracción de germinación es constante, y posiblemente relativamente alta, una vez superado el umbral de respuesta. El comportamiento de este banco de semillas tiene sentido si se considera el peculiar clima semidesértico de la Prepuna: lluvias estivales relativamente más confiables que las de otros desiertos.
Germination experiments were carried out to determine the minimum water quantity that triggers germination (response threshhold) of the persistent seed bank in an Andean semidesert with summer rains, the Prepuna, and also to know seed response to different levels of simulated precipitation, all in the context of theories about seed bank behavior in arid and semiarid environments. The experiments were done in small pots arranged in a randomized block design. There were six irrigation treatments: 0 (control), 15, 25, 40, 80 and 160 mm, that were added cumulatively (5 mm events). The response threshhold detected was 40 mm. The irrigation above the germination threshold did not produce significantly different results from those observed with 40 mm, and that suggests the existence of a constant germination fraction, and possibly relatively high, once the response theshhold is surpassed. The response of this seed bank makes sense if the peculiar semidesert climate of the Prepuna is considered: summer rains more reliable than those in other deserts.
Germination experiments were carried out to determine the minimum water quantity that triggers germination (response threshhold) of the persistent seed bank in an Andean semidesert with summer rains, the Prepuna, and also to know seed response to different levels of simulated precipitation, all in the context of theories about seed bank behavior in arid and semiarid environments. The experiments were done in small pots arranged in a randomized block design. There were six irrigation treatments: 0 (control), 15, 25, 40, 80 and 160 mm, that were added cumulatively (5 mm events). The response threshhold detected was 40 mm. The irrigation above the germination threshold did not produce significantly different results from those observed with 40 mm, and that suggests the existence of a constant germination fraction, and possibly relatively high, once the response theshhold is surpassed. The response of this seed bank makes sense if the peculiar semidesert climate of the Prepuna is considered: summer rains more reliable than those in other deserts.
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No. 33