Leaf traits and insect herbivory levels in two Mediterranean oaks and their hybrids through contrasting environmental gradients.

Insect herbivory has attracted enormous attention from researchers due to its effects on plant fitness. However, there remain questions such as what are the most important leaf traits that determine consumption levels, whether there are latitudinal gradients in herbivore pressure, or whether there are differences in susceptibility between hybrids and their parental species. In this work we address all these issues in two species of Mediterranean Quercus (Q.

Photosynthetic performance under adaxial and abaxial illumination in three Mediterranean Quercus species differing in branch architecture and individual leaf area.

Light availability effects on canopy-level carbon balance constitute an especially difficult issue to address, owing to the strong spatial and temporal changes of the light environment within the canopy. One of the least explored aspects in relation to light environment is the interaction between leaf angle and leaf anatomy. The inclination of the leaf may affect the distribution of light between the adaxial and abaxial surface.

Branch architecture in relation to canopy positions in three Mediterranean oaks.

Branch architecture is a key determinant of plant performance owing to its role in a light interception by photosynthetic tissues. However, under stressed conditions, excess light may be harmful to the photosynthetic apparatus, and plants often present structural mechanisms to avoid photoinhibition. Three-dimensional models were constructed of the aerial parts in different locations within the crown of three co-occurring tree species (Quercus ilex, Q.

Deciduous and evergreen oaks show contrasting adaptive responses in leaf mass per area across environments.

Increases in leaf mass per area (LMA) are commonly observed in response to environmental stresses and are achieved through increases in leaf thickness and/or leaf density. Here, we investigated how the two underlying components of LMA differ in relation to species native climates and phylogeny, across deciduous and evergreen species. Using a phylogenetic approach, we quantified anatomical, compositional and climatic variables from 40 deciduous and 45 evergreen Quercus species from across the Northern Hemisphere growing in a common garden.

Foliar plasticity related to gradients of heat and drought stress across crown orientations in three Mediterranean Quercus species.

Studies on plasticity at the level of a single individual plant provide indispensable information to predict leaf responses to climate change, because they allow better identification of the environmental factors that determine differences in leaf traits in the absence of genetic differences. Most of these studies have focused on the responses of leaf traits to variations in the light environment along vertical gradients, thus paying less attention to possible differences in the intensity of water stress among canopy orientations. In this paper, we analyzed the differences in leaf traits traditionally associated with changes in the intensity of water stress between east and west crown orientations in three Quercus species.