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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Rangeland Resources & Systems Research » Research » Publications at this Location » Publication #353991
Title: Extending the osmometer method for assessing drought tolerance in herbaceous species

Author
item GRIFFIN-NOLAN, R - Colorado State University
item OCHELTREE, T - Colorado State University
item MUELLER, K - Cleveland State University
item Blumenthal, Dana
item Kray, Julie
item KNAPP, A - Colorado State University

Submitted to: Oecologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/2/2019
Publication Date: 1/9/2019
Citation: Griffin-Nolan, R.J., Ocheltree, T.W., Mueller, K.E., Blumenthal, D.M., Kray, J.A., Knapp, A.K. 2019. Extending the osmometer method for assessing drought tolerance in herbaceous species. Oecologia. 189(2):353-363. https://doi.org/10.1007/s00442-019-04336-w.
DOI: https://doi.org/10.1007/s00442-019-04336-w

Interpretive Summary: Understanding plant drought tolerance is essential for understanding dry ecosystems and predicting responses to climate change. As such, there is need for an accurate and rapid methodology for assessing drought tolerance strategies in plants. Leaf osmotic potential at full turgor has been identified as a useful trait for understanding leaf-level drought tolerance, but the applicability of this method has only been tested in woody species. Here, we validate the use of leaf osmotic potential for understanding drought tolerance in grassland ecosystems. We demonstrate that leaf osmotic potential is closely correlated with other measures of drought tolerance, including turgor loss point, leaf dry matter content, and vulnerability to xylem cavitation, as well as aridity within a plant species’ range. Validation of this method in an herbaceous-dominated system paves the way for rapid surveys of drought tolerance across plant functional groups, which should improve predictions of ecosystem responses to changing precipitation regimes.

Technical Abstract: Understanding plant drought tolerance is essential for understanding dry ecosystems and predicting responses to climate change. As such, there is need for an accurate and rapid methodology for assessing drought tolerance strategies in plants. Leaf osmotic potential at full turgor has been identified as a useful trait for understanding leaf-level drought tolerance and is correlated with water availability globally. The measurement speed of leaf osmotic potential has been increased 50-fold with the introduction of the osmometer method by Bartlett et al. (2012); however, the applicability of this method has only been tested in woody species. Here, we validate the osmometer method for use in grassland ecosystems dominated by herbaceous species with large midrib veins. Our model for predicting leaf turgor loss point from leaf osmotic potential (Turgor loss point = 0.813*osmotic potential – 0.8604) in grassland species is nearly identical to the model presented for woody species. Additionally, we report that osmotic potential was well correlated with other traits linked to drought tolerance (namely, leaf dry matter content and leaf vulnerability to xylem cavitation) as well as bioclimatic variables related to aridity. Validation of this method in an herbaceous-dominated system paves the way for rapid community-scale surveys of drought tolerance across plant functional groups, which should improve predictions of ecosystem responses to changing precipitation regimes.