Document Type
Article
Publication Date
2-2024
Publisher
Oxford University Press
Source Publication
AoBP
Source ISSN
2041-2851
Original Item ID
DOI: 10.1093/aobpla/plae012
Abstract
Climate change is dramatically altering global precipitation patterns across terrestrial ecosystems, making it critically important that we understand both how and why plant species vary in their drought sensitivities. Andropogon gerardii and Schizachyrium scoparium, both C4 grasses, provide a model system for understanding the physiological mechanisms that determine how species of a single functional type can differ in drought responses, an issue remains a critical gap in our ability to model and predict the impacts of drought on grassland ecosystems. Despite its greater lability of foliar water content, previous experiments have demonstrated that S. scoparium maintains higher photosynthetic capacity during droughts. It is therefore likely that the ability of S. scoparium to withstand drought instead derives from a greater metabolic resistance to drought. Here, we tested the following hypotheses: (H1) A. gerardii is more vulnerable to drought than S. scoparium at both the population and organismal levels, (H2) A. gerardii is less stomatally flexible than S. scoparium, and (H3) A. gerardii is more metabolically limited than S. scoparium. Our results indicate that it is actually stomatal limitations of CO2 supply that limit A. gerardii photosynthesis during drought. Schizachyrium scoparium was more drought-resistant than A. gerardii based on long-term field data, organismal biomass production and physiological gas exchange measurements. While both S. scoparium and A. gerardii avoided metabolic limitation of photosynthesis, CO2 supply of A. gerardii was greatly reduced during late-stage drought stress. That two common, co-occurring C4 species possess such different responses to drought highlights the physiological variability inherent within plant functional groups and underscores the need for more studies of C4 drought tolerance.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Dekirmenjian, Alina; Montano, Diego; Budny, Michelle L.; and LeMoine, Nathan P., "Schizachyrium scoparium (C4) Better Tolerates Drought than Andropogon gerardii (C4) via Constant CO2 Supply for Photosynthesis During Water Stress" (2024). Biological Sciences Faculty Research and Publications. 991.
https://epublications.marquette.edu/bio_fac/991
Comments
Published version. AoBP, Vol. 16, No. 2 (February, 2024). DOI. © The Author(s) 2024. Published by Oxford University Press on behalf of the Annals of Botany Company. Used with permission.