INIBIOMA   20415
INSTITUTO DE INVESTIGACIONES EN BIODIVERSIDAD Y MEDIOAMBIENTE
Unidad Ejecutora - UE
artículos
Título:
Seed longevity and fire: germination responses of an exotic perennial herb in NW Patagonian grasslands (Argentina)
Autor/es:
FRANZESE, J. Y L. GHERMANDI.
Revista:
PLANT BIOLOGY
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2011 p. 865 - 871
ISSN:
1435-8603
Resumen:
ABSTRACT
Fire affects grassland composition by selectively influencing recruitment. Some exotic
species can increase their abundance as a consequence of fire-stimulated seed
germination, but response may depend on seed age. Rumex acetosella L. (Polygonaceae,
sheeps sorrel) is a cosmopolitan herb that has invaded NW Patagonias grasslands.
This species forms persistent soil seed banks and increases after disturbances,
particularly fire. We studied how fire and seed longevity influence R. acetosella germination.
In 2008, we conducted laboratory experiments where we exposed different-
aged seeds (up to 19 years old) to heat, smoke, charcoal, ash and control
treatments. Total percentage germination and mean germination time depended on
both seed age and fire treatment. Germination of younger seeds decreased with
increasing temperature. There was no general pattern in germination responses of
different-aged seeds to smoke, charcoal and ash. While smoke improved the germination
of fresh seeds, charcoal decreased germination. Germination of untreated
seeds was negatively correlated with seed age, and mean germination time increased
with seed age. In most treatments, fresh seeds had lower germination than 15-
year-old seeds, indicating an after-ripening requirement. Smoke stimulates R. acetosellaRumex acetosella L. (Polygonaceae,
sheeps sorrel) is a cosmopolitan herb that has invaded NW Patagonias grasslands.
This species forms persistent soil seed banks and increases after disturbances,
particularly fire. We studied how fire and seed longevity influence R. acetosella germination.
In 2008, we conducted laboratory experiments where we exposed different-
aged seeds (up to 19 years old) to heat, smoke, charcoal, ash and control
treatments. Total percentage germination and mean germination time depended on
both seed age and fire treatment. Germination of younger seeds decreased with
increasing temperature. There was no general pattern in germination responses of
different-aged seeds to smoke, charcoal and ash. While smoke improved the germination
of fresh seeds, charcoal decreased germination. Germination of untreated
seeds was negatively correlated with seed age, and mean germination time increased
with seed age. In most treatments, fresh seeds had lower germination than 15-
year-old seeds, indicating an after-ripening requirement. Smoke stimulates R. acetosellaR. acetosella germination.
In 2008, we conducted laboratory experiments where we exposed different-
aged seeds (up to 19 years old) to heat, smoke, charcoal, ash and control
treatments. Total percentage germination and mean germination time depended on
both seed age and fire treatment. Germination of younger seeds decreased with
increasing temperature. There was no general pattern in germination responses of
different-aged seeds to smoke, charcoal and ash. While smoke improved the germination
of fresh seeds, charcoal decreased germination. Germination of untreated
seeds was negatively correlated with seed age, and mean germination time increased
with seed age. In most treatments, fresh seeds had lower germination than 15-
year-old seeds, indicating an after-ripening requirement. Smoke stimulates R. acetosellaR. acetosella
germination, causing successful recruitment during post-fire conditions. Fresh
seeds are particularly responsive to fire factors, possibly because they have not experienced
physical degradation and are more receptive to environmental stimuli.
Knowing the colonisation potential from the soil seed bank of this species during
post-fire conditions will allow us to predict their impact on native communities.