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Population divergence in the plasticity of the response of Quercus coccifera to the light environment
Article first published online: 9 MAY 2002
Volume 15, Issue 1, pages 124–135, February 2001
How to Cite
L., B., Martínez-Ferri, E., Valladares, F., Pérez-Corona, M. E., Baquedano, F. J., Castillo, F. J. and Manrique, E. (2001), Population divergence in the plasticity of the response of Quercus coccifera to the light environment. Functional Ecology, 15: 124–135. doi: 10.1046/j.1365-2435.2001.00505.x
- Issue published online: 9 MAY 2002
- Article first published online: 9 MAY 2002
- genetic variability;
- leaf azimuth;
- phenotypic plasticity;
- photochemical efficiency
- 1Quercus coccifera, a slow-growing, evergreen oak, grows in contrasting environments in the Mediterranean Basin. Habitat-based selection may have promoted divergence between populations with respect to phenotypic plasticity and genetic variability.
- 2We tested the hypothesis that populations of the Q. coccifera originating from a rock outcrop, a continental garrigue formation and an oceanic forest would differ in their plastic response to light intensity. Plants from these populations were grown from acorns in a common garden at 100% and 20% full sunlight. Light response analysis was based on photochemical efficiency, xanthophyll pool, nutrient allocation, growth, crown architecture and light absorption.
- 3Light-responsive characters ranged from the subcellular to the whole-plant level. The greatest divergences between sun and shade phenotypes were observed in leaf size, leaf angle and leaf area ratio. However, plasticity in these traits depended on plant provenance.
- 4Regardless of the level of organization, populations were invariably ranked in the same order of plasticity when averaged over light-responsive features, with plants originating from the rock outcrop showing the least plasticity and those from the forest the largest. The forest population also had the greatest genetic variability with respect to the isoperoxidase polymorphism.
- 5Among populations, plants originating from the phosphorus-deficient rock outcrop contained 30% more P per unit dry weight. Plants from the forest population had 5% more photoprotective xanthophylls, 30% larger total leaf area, with less lobed and larger leaves and a differential plasticity in leaf azimuth.
- 6Differences among populations suggested ecotypic differentiation towards less phenotypic plasticity in the most homogeneous light environments. The ecological breadth of the species seemed to be derived not only from its tolerance of Mediterranean conditions but also from the specialization of its populations in contrasting habitats.