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Descripción
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| Although summer drought is usually the main limiting ecological factor conditioning the regeneration of holm oak forests in the Iberian Peninsula, in continental areas mild frost events are frequent during the critical period of acorn release, germination and seedling establishment. The impact of such frost events on regeneration has not been studied so far. On the other hand, genetic variability for frost tolerance has been found on many plant species at different ages and in different organs. We used controlled climatic chambers to artificially simulate frost nights covering a set of minimum temperatures to evaluate the impact of low temperatures on the germinative capacity of acorns collected from 30 trees growing under natural conditions in a holm oak dehesa (savanna-like holm oak stand) in central Spain. The trees belong to two different groups according their growth habit: dehesa (agroforestry system with scarce holm oak trees traditionally selected for acorn production) and coppices (resprouting stand traditionally used for firewood production) in the same state; we collected acorns from 15 trees of each group. Minimum test temperatures were chosen to cover and slightly surpass those observed in the study area during the winter. The remaining seeds were sown and the plants obtained were used to test frost tolerance of seedling leaves in the beginning of the first autumn. Results show that minimum temperatures below ? 6° C, which occur on a regular basis during winter in the study area, seriously affect seed survival, thus constituting a limiting factor for regeneration. Variability among groups was observed for this trait, being the acorns from the coppice group significantly more sensitive, with differences among families within groups. On the contrary, seedlings from all studied families proved to be able to endure the temperatures observed in early frost events. | |
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Internacional
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Si |
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Nombre congreso
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Restoring forests: advances in techniques and theory. IUFRO Conference |
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Tipo de participación
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960 |
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Lugar del congreso
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Madrid |
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Revisores
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Si |
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ISBN o ISSN
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978-84-614-8713-4 |
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DOI
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Fecha inicio congreso
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27/09/2011 |
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Fecha fin congreso
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29/09/2011 |
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Desde la página
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1 |
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Hasta la página
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11 |
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Título de las actas
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Restoring forests: advances in techniques and theory |