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Descripción
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| The distribution of the natural populations of pines in the Iberian Peninsula is related to the variation in space and intensity of summer drought and low winter temperatures. Pinus sylvestris and P. uncinata, the mountain pines, concentrate in the highest parts of the largest Iberian mountain ranges under wet and cold conditions. In contrast, P. halepensis and P. pinaster, the lowland pines, tend to concentrate at low altitudes, where drought and high summer temperature are the main plant life constraints. These differences in distribution might be attributed to seedling differences in water use efficiency and the capacity to cope with drought. We compared the field survival and growth of Pinus sylvestris, P. uncinata, P. halepensis and P. pinaster seedlings. Moreover, we assessed the root growth and hydraulic resistance, and the water use efficiency (WUE) of pine seedlings under contrasting environmental conditions. Field survival and shoot growth of 1 year-old seedlings was compared in a common garden experiment laid in a lowland site that experiences pronounced summer drought stress. Root hydraulic was measured in seedlings at 20 and 10 ºC using a pressure bomb. Root growth and WUE were measured in seedlings cultivated under two contrasting levels of soil water availability. Root growth was measured in a rhizotron for 1 year and WUE was measured as the seedling mass increase per volume of transpired water after 2 months. After the first summer, field survival and shoot growth of P. uncinata was lowest (survival 66%) while lowland pines, especially in P. halepensis, was the highest (survival >97%). Pinus sylvestris survival was 94% and its growth was significantly higher than P. uncinata growth but lower than the growth of lowland pines. Irrespective of soil water availability, lowland pines had higher WUE than mountain pines. Species ranking according to WUE were: P. pinaster ? P. halepensis >> P. sylvestris ? P. uncinata. Maximum depth and growth of root system was higher in P. halepensis and P. pinaster than in both mountain pines. Moreover, root hydraulic resistance was 2-4 times lower in lowland pines than in the mountain pines, irrespective of soil temperature. We evidence that the natural distribution of four Iberian pine species can be explained by species ecophysiological differences to cope with drought at the seedling stage, with seedlings of lowland pines having greater ability to access and use more efficiently water than mountain pines seedlings. | |
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Internacional
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Si |
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Nombre congreso
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medPINE5- International Conference on Mediterranean pines |
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Tipo de participación
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960 |
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Lugar del congreso
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Solsona |
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Revisores
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Si |
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ISBN o ISSN
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000-0-00-000000-0 |
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DOI
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DOI: 10.13140/2.1.5183.5203 |
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Fecha inicio congreso
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22/09/2014 |
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Fecha fin congreso
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26/09/2014 |
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Desde la página
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13 |
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Hasta la página
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13 |
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Título de las actas
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5th International Conference on Mediterranean Pines (medpine5) Solsona, Spain, September 22-26, 2014 http://medpine5.ctfc.es/ |