The Kinetics of Mesophyll Conductance and Photorespiration During Light Induction
Mesophyll conductance to CO<sub>2</sub> (<i>g</i><sub>m</sub>) act as a significant limiting factor influencing the CO<sub>2</sub> assimilation rate (<i>A</i><sub>N</sub>) during photosynthetic induction. However, the effect of...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-03-01
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| Series: | Plants |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2223-7747/14/6/850 |
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| Summary: | Mesophyll conductance to CO<sub>2</sub> (<i>g</i><sub>m</sub>) act as a significant limiting factor influencing the CO<sub>2</sub> assimilation rate (<i>A</i><sub>N</sub>) during photosynthetic induction. However, the effect of vapor pressure deficit (VPD) on <i>g</i><sub>m</sub> kinetics during light induction is not well clarified. We combined gas exchange with chlorophyll fluorescence measurements to assess the induction kinetics of <i>g</i><sub>m</sub> during light induction under contrasting vapor pressure deficit (VPD) in two tree species with different stomatal conductance (<i>g</i><sub>s</sub>) behavior, <i>Catalpa fargesii</i> and <i>Pterocarya stenoptera</i>. Our results revealed three key findings: (1) the coordination of <i>g</i><sub>m</sub> and <i>g</i><sub>s</sub> kinetics during light induction occurred in <i>C. fargesii</i> but not in <i>P. stenoptera</i>, and the model of <i>g</i><sub>s</sub> kinetics largely determines whether the coordination of <i>g</i><sub>s</sub> and <i>g</i><sub>m</sub> exist in a given species; (2) a high VPD induced simultaneous changes in <i>g</i><sub>s</sub> and <i>g</i><sub>m</sub> kinetics in <i>C. fargesii</i> but had separated effects on <i>g</i><sub>s</sub> and <i>g</i><sub>m</sub> kinetics in <i>P. stenoptera</i>, indicating that the response of <i>g</i><sub>m</sub> kinetics during light induction to VPD differs between species; and (3) the relative contribution of photorespiration to total electron flow was flexible in response to the change in relative diffusional and biochemical limitations, pointing out that photorespiration has a significant role in the regulation of photosynthetic electron flow during light induction. These results provide new sight into the species-dependent kinetics of <i>g</i><sub>m</sub> and photorespiration during light induction. |
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| ISSN: | 2223-7747 |