title: Relations between water balance, wood traits and phenological behavior of tree species from a tropical dry forest in Costa Rica--a multifactorial study.
abstract: Drought tolerance is a key factor for the establishment and survival of tree species in tropical ecosystems. Specific mechanisms of drought resistance can be grouped into four functional ecotypes based on differences in leaf fall behavior: deciduous, brevi-deciduous, stem succulent and evergreen. To identify the key factors influencing phenology and cambial activity and thus drought tolerance, we tested the stomatal conductance, leaf water potential and stable carbon isotopes in the leaves and wood of 12 species from a tropical dry forest in Costa Rica. With wood anatomical techniques, we further studied seasonal cambial activity and a suite of wood traits related to water transport for each of the functional ecotypes. Using a principal component analysis, we identified two groups of variables that can be related to (i) hydraulic conductivity and (ii) control of transpiration and water loss. Hydraulic conductivity is controlled by vessel size as the limiting variable, water potential as the driving force and wood density as the stabilizing factor of the anatomical structure of an effective water transport system. Stomatal control plays a major role in terms of water loss or saving and is the dominant factor for differences in phenological behavior. Stem succulent species in particular developed a rarely identified but highly effective strategy against drought stress, which makes it a successful pioneer species in tropical dry forests.
authors: Crop Production Systems in the Tropics, Department for Crop Sciences, University of Göttingen, Grisebachstraße 6, D-37077 Göttingen, Germany. mworbes@gwdg.de
authors: Martin
authors: M
authors: Worbes
authors: Sofie
authors: S
authors: Blanchart
authors: Esther
authors: E
authors: Fichtler
mesh_terms: D058506:Cambium / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D002247:Carbon Isotopes / Q000032:analysis; D003364:Costa Rica; D055864:Droughts; D019684:Magnoliopsida / Q000166:cytology / Q000254:growth & development / Q000502:physiology*; D015999:Multivariate Analysis; D010641:Phenotype; D018515:Plant Leaves / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D018547:Plant Stems / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D054046:Plant Stomata / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D018526:Plant Transpiration / Q000502:physiology*; D014197:Trees; D014329:Tropical Climate; D014867:Water / Q000502:physiology*; D014934:Wood / Q000166:cytology / Q000254:growth & development / Q000502:physiology*
chemical_list: D002247:Carbon Isotopes; D014867:Water
keywords: carbon isotopes; phenological ecotypes; stem succulent; stomatal conductance; tropical dry forest; wood anatomy