Person: Delgado Sáez, Juan Antonio
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First Name
Juan Antonio
Last Name
Delgado Sáez
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Biológicas
Department
Biodiversidad, Ecología y Evolución
Area
Ecología
Identifiers
3 results
Search Results
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Item The expression of light-related leaf functional traits depends on the location of individual leaves within the crown of isolated Olea europaea trees(Annals of Botany, 2016) Escribano Rocafort, Adrián Gaspar; Ventre-Lespiaucq, Agustina B.; Granado Yela, Carlos; Rubio de Casas, Rafael; Delgado Sáez, Juan Antonio; Balaguer, LuisBackground: The spatial arrangement and expression of foliar syndromes within tree crowns can reflect the coupling between crown form and function in a given environment. Isolated trees subjected to high irradiance and concomitant stress may adjust leaf phenotypes to cope with environmental gradients that are heterogeneous in space and time within the tree crown. The distinct expression of leaf phenotypes among crown positions could lead to complementary patterns in light interception at the crown scale. Methods: We quantified eight light-related leaf traits across 12 crown positions of ten isolated Olea europaea trees in the field. Specifically, we investigated whether the phenotypic expression of foliar traits differed among crown sectors and layers and five periods of the day from sunrise to sunset. We investigated the consequences in terms of the exposed area of the leaves at the tree scale during a single day. Key Results: All traits differed among crown positions except the length-to-width ratio of the leaves. We found a strong complementarity in the patterns of the potential exposed area of the leaves among day periods as a result of a non-random distribution of leaf angles across the crown. Leaf exposure at the outer layer was below 60 % of the displayed surface, reaching maximum interception during morning periods. Daily interception increased towards the inner layer, achieving consecutive maximization from east to west positions within the crown, matching the sun’s trajectory. Conclusions: The expression of leaf traits within isolated trees of O. europaea varies continuously through the crown in a gradient of leaf morphotypes and leaf angles depending on the exposure and location of individual leaves. The distribution of light-related traits within the crown and the complementarity in the potential exposure patterns of the leaves during the day challenges the assumption of low trait variability within individuals.Item Sink strength manipulation in branches of a Mediterranean woody plant suggests sink-driven allocation of biomass in fruits but not of nutrients in seeds(Acta Physiologiae Plantarum, 2016) Catalán, Pablo; Delgado Sáez, Juan Antonio; Jiménez Escobar, María Dolores; Balaguer Núñez, LuisThe relative autonomy of branches within an individual plant may favor different resource allocation responses after reproductive losses. The assessment of these reproductive strategies at the branch level before their integration at the plant level would provide more insight into how plants deal with reproductive losses. Here, we present a field experiment to assess changes in the allocation strategies at the branch level after sink strength manipulation in a Mediterranean woody plant (Cistus ladanifer). We applied three levels of removal of developing fruits (75, 25 and 0 %) on branches of the same plants, and measured their effects on resource allocation (biomass, nitrogen and phosphorus) and seed production after controlling for the effects of branch diameter and leaf weight per branch. Our results suggest that after experimental fruit thinning, C. ladanifer branches presented a sink-driven allocation of biomass to fruits but this was not the case for the allocation of nutrients to seeds, which could be driven by competition with leaf biomass. Reductions in biomass per fruit resulted in a reduction in seed output since the average weight per seed remained constant. From these results, it could be suggested that an heterogeneous distribution of fruit losses among the branches within a crown would produce a higher impact on reproductive output than a more equitable distribution.Item Intraindividual variation in light-related functional traits: magnitude and structure of leaf trait variability across global scales in Olea europaea trees(Trees, 2017) Escribano Rocafort, Adrián Gaspar; Ventre Lespiaucq, Agustina Bernardita; Granado Yela, Carlos; Rubio de Casas, Rafael; Delgado Sáez, Juan Antonio; Escudero Alcántara, Adrián; Balaguer, LuisIntraspecific variation in leaf functional traits can play a crucial role at multiple ecological scales. However, our understanding of leaf functional trait variation (FV) across spatial scales is limited. Moreover, the influence of FV in specific responses to the environment remains poorly assessed. We investigated FV across multiple nested ecological scales in a set of leaf traits related to light interception and photosynthetic performance in eight populations of Olea europaea trees distributed over a wide latitudinal gradient (~60°). Specifically, we measured SLA, leaf shape, leaf’s spatial position (leaf angles) and leaf’s potential exposure to direct sunlight (silhouette area of the leaf blade and silhouette to area ratio of the leaf blade). The variability in leaf traits revealed two main patterns depending on the considered trait. Differences among sites absorbed >50% of the trait variation related to leaf shape and structure. Conversely, traits related to leaf position and exposure to direct light varied mostly within individuals among crown positions. The variation within trees for multiple traits ranged from 4 to 14%. Trees of equatorial populations had wider, thinner and more exposed leaves to direct light than trees of the remaining populations. The FV for multiple leaf traits at the tree scale was spatially structured within the tree crown and was higher for populations at the equator than for populations located in other latitudes. The differences among traits and scales in the magnitude of FV revealed a complex structure that could be linked to local adaptation.