Increased bundle sheath leakiness of <scp> CO <sub>2</sub> </scp> during photosynthetic induction shows a lack of coordination between the <scp> C <sub>4</sub> </scp> and <scp> C <sub>3</sub> </scp> cycles

Wang, Yu and Stutz, Samantha S. and Bernacchi, Carl J. and Boyd, Ryan A. and Ort, Donald R. and Long, Stephen P. (2022) Increased bundle sheath leakiness of <scp> CO <sub>2</sub> </scp> during photosynthetic induction shows a lack of coordination between the <scp> C <sub>4</sub> </scp> and <scp> C <sub>3</sub> </scp> cycles. New Phytologist. ISSN 0028-646X (In Press)

Full text not available from this repository.

Abstract

Use of a complete dynamic model of NADP-ME C4 photosynthesis indicated during dark or shade to high-light transitions induction of the C4 pathway was more rapid than that of the C3, resulting in a predicted transient increase in bundle-sheath CO2 leakiness (ϕ) Previously, ϕ was measured at steady-state, here we developed a new method, coupling a tunable diode laser absorption spectroscope (TDL) with a gas exchange system, to track ϕ in sorghum and maize through the non-steady-state condition of photosynthetic induction. In both species, ϕ showed a transient increase to >0.35 before declining to a steady-state of 0.2 by 1500 s after illumination. Average ϕ was 60% higher than at steady-state over the first 600 s of induction and 30% higher over the first 1500 s. The transient increase in ϕ, which was consistent with the model prediction, indicated that capacity to assimilate CO2 into the C3 cycle in the bundle-sheath failed to keep pace with the rate of dicarboxylate delivery by the C4 cycle. Because non-steady-state light conditions are the norm in field canopies, the results suggest that ϕ in these major crops in the field is significantly higher and energy conversion efficiency lower than previous measured values under steady-state conditions.

Item Type:
Journal Article
Journal or Publication Title:
New Phytologist
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2700
Subjects:
ID Code:
176803
Deposited By:
Deposited On:
29 Sep 2022 15:05
Refereed?:
Yes
Published?:
In Press
Last Modified:
27 Nov 2022 02:30