Leaf phenotypic variation in natural populations of Quillaja saponaria and its relationship with climatic variation

Quillaja saponaria is a sclerophyllus evergreen tree species distributed from 30° to 38° S in Central Chile. In this wide distribution it is expected that the species exhibits phenotypic plasticity in the morphology of leaves associated to climate variation; however, the information on this topic is still scarce. We studied leaf phenotypic variation and its relationship with temperature, precipitation, and aridity in 85 stands of Q. saponaria throughout the natural distribution of the species. The results show that the basal diameter of petiole, the number of secondary veins, and the basal diameter of the principal vein increased with precipitation and decreased with aridity, while the length, basal diameter and the relative length of the petiole decreased with temperature. This confirms that phenotypic variation for foliar characters in Q. saponaria is related to climatic variables indicating an adapting capability of the species to the wide range of environmental conditions in which grows.