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Colorado State University (2017)

Is it plastic or just fantastic ? : understanding the role of plasticity and local adaptation in the drought tolerance of Bouteloua gracilis

Bushey, Julie A.

Titre : Is it plastic or just fantastic ? : understanding the role of plasticity and local adaptation in the drought tolerance of Bouteloua gracilis

Auteur : Bushey, Julie A.

Université de soutenance : Colorado State University

Grade : Master of Science (M.S.) 2017

Résumé
The ability of an organism to tolerate or acclimate to drought may become a major driver of changes in community composition, carbon and water cycles and ecosystem services as we encounter increasing severity and frequency of droughts in the face of global change. Drought tolerance traits allow us to quantify functional attributes of individual species, but the expected variability of drought tolerance traits within a species is uncertain. Although some variability in plant traits are expected, it is unknown whether the local adaptation of populations can explain the expected variability. The objective of this study is the quantification of plasticity of drought tolerance responses across populations of Bouteloua gracilis to different soil moisture levels. B. gracilis is a C4 perennial grass that dominates grasslands across a range of climates and is a major contributor of ecosystem function and services within these systems. Populations from less arid sites showed greater osmotic adjustment and higher midday water potentials when grown under limited soil moisture conditions. Populations from arid sites did not adjust osmotic potential but showed more negative midday water potentials while maintaining higher growth rates. This variation in response to lowered soil moisture indicates a potential shift in water use strategy across an aridity gradient that has implications for land managers seeking to restore B. gracilis dominated ecosystems with drought tolerant material.

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Page publiée le 19 novembre 2018