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CO2 availability influences hydraulic function of C3 and C4 grass leaves

Taylor, Samuel and Aspinwall, Michael J. and Blackman, Chris J. and Choat, Brendan and Tissue, David T. and Ghannoum, Oula (2018) CO2 availability influences hydraulic function of C3 and C4 grass leaves. Journal of Experimental Botany. ISSN 0022-0957

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Abstract

Atmospheric CO2 (ca) has increased since the last glacial period, increasing photosynthetic water use efficiency and improving plant productivity. Evolution of C4 photosynthesis at low ca led to decreased stomatal conductance (gs), which provided an advantage over C3 plants that may be reduced by rising ca. Using controlled environments, we determined how increasing ca affects C4 water use relative to C3 plants. Leaf gas exchange and mass per area (LMA) were measured for four C3 and four C4 annual, crop-related grasses at glacial (200), ambient (400), and super-ambient (640 µmol mol−1) ca. C4 plants had lower gs, which resulted in a water use efficiency advantage at all ca and was broadly consistent with slower stomatal responses to shade, indicating less pressure on leaf water status. At glacial ca, A and LMA were lower for C3 than C4 leaves, and C3 and C4 grasses decreased leaf hydraulic conductance (Kleaf) similarly, but only C4 leaves decreased osmotic potential at turgor-loss. Greater carbon availability in C4 leaves at glacial ca generated different hydraulic adjustment relative to C3 plants. At current and future ca, C4 grasses have advantages over C3 grasses due to lower gs, lower stomatal sensitivity, and higher absolute water use efficiency.

Item Type: Journal Article
Journal or Publication Title: Journal of Experimental Botany
Uncontrolled Keywords: C4 photosynthesis ; glacial CO2 ; grasses ; leaf gas exchange ; leaf hydraulic conductance ; osmotic adjustment ; pressure-volume curve ; stomatal conductance ; turgor loss point
Subjects:
Departments: Faculty of Science and Technology > Lancaster Environment Centre
ID Code: 124019
Deposited By: ep_importer_pure
Deposited On: 12 Mar 2018 13:32
Refereed?: Yes
Published?: Published
Last Modified: 11 Apr 2018 04:18
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/124019

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