Leaf habit determines the hydraulic and resource-use strategies in tree saplings from the Sonoran Desert
Por:
González-Rebeles G., Méndez-Alonzo R., Paz H., Terrazas T., Tinoco-Ojanguren C.
Publicada:
1 ene 2023
Resumen:
The drought susceptibility of woody saplings may explain their low survival in arid environments. Therefore, it is critical to determine which morphological and physiological traits are more responsive to drought among young plants. This study tested whether plant responses to experimental drought differ between two plant functional groups: the deciduous and evergreen species. We predicted that deciduous species would present a tighter stomatal control under drought, coupled with fast carbon fixation under no stress, tending toward isohydry and faster growth rates than the evergreen species. Using 1-year-old saplings from three evergreen and four deciduous Sonoran Desert tree species, we evaluated their hydraulic and gas exchange traits under three experimental irrigation conditions: high, intermediate and low water availability. We measured CO2 assimilation rates (A), stomatal conductance (gs), the level of iso-anisohydry (as the plant's ability to maintain constant their water potential) and seven morphological and growth-related traits throughout 2 months. Under high water availability, saplings reached their maximum values of A and gs, which were significantly higher for deciduous than evergreen species. Correlations among hydroscape area (HA) and leaf traits positioned species along the iso/anisohydric continuum. Deciduous species presented isohydric characteristics, including low HA, high gs, A and Huber values (HVs), and traits indicative of a faster use of resources, such as low stem-specific density (SSD) and low leaf mass per area (LMA). By contrast, evergreen species showed traits that indicate slow resource use and anisohydric behavior, such as high HA, SSD and LMA, and low gs, A and HVs. Deciduous species drastically reduced gas exchange rates in response to drought, while evergreen maintained low rates independently of drought intensity. Overall, desert saplings showed strategies concordant with the iso-anisohydric continuum and the fast-slow use of resources. © The Author(s) 2022. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.
Filiaciones:
González-Rebeles G.:
Departamento de Ecología de la Biodiversidad, Instituto de Ecología, Universidad Nacional Autónoma de México, Campus Hermosillo, Hermosillo, Sonora 83250, Mexico
Posgrado en Ciencias Biológicas, Unidad de Posgrado, Edificio A, Circuito de Posgrados, 1o PisoCiudad Universitaria, Ciudad de México 04510, Mexico
Méndez-Alonzo R.:
Departamento de Biología de la Conservación, Centro de Investigación Científica y de Educación Superior de Ensenada 22860Baja California, Mexico
Paz H.:
Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Morelia, Michoacán 58190, Mexico
Terrazas T.:
Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México 3004, Mexico
Tinoco-Ojanguren C.:
Departamento de Ecología de la Biodiversidad, Instituto de Ecología, Universidad Nacional Autónoma de México, Campus Hermosillo, Hermosillo, Sonora 83250, Mexico
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