Related Experiment Video
Updated: Aug 8, 2026

Evaluation of Photosynthetic Efficiency in Photorespiratory Mutants by Chlorophyll Fluorescence Analysis
Published on: December 9, 2022
CO(2) Inhibits Respiration in Leaves of Rumex crispus L
J S Amthor1, G W Koch, A J Bloom
1Department of Agronomy and Range Science, University of California, Davis, California 95616.
Abstract:
Curly dock (Rumex crispus L.) was grown from seed in a glasshouse at an ambient CO(2) partial pressure of about 35 pascals. Apparent respiration rate (CO(2) efflux in the dark) of expanded leaves was then measured at ambient CO(2) partial pressure of 5 to 95 pascals. Calculated intercellular CO(2) partial pressure was proportional to ambient CO(2) partial pressure in these short-term experiments. The CO(2) level strongly affected apparent respiration rate: a doubling of the partial pressure of CO(2) typically inhibited respiration by 25 to 30%, whereas a decrease in CO(2) elicited a corresponding increase in respiration. These responses were readily reversible. A flexible, sensitive regulatory interaction between CO(2) (a byproduct of respiration) and some component(s) of heterotrophic metabolism is indicated.
Related Concept Videos
Adaptations that Reduce Water Loss
C4 Pathway and CAM
C4 Pathway
The C4 pathway is used by plants such as...
Chemical Factors Affecting Respiration Centers
CO2 has a potent influence on respiration and is strictly regulated. Under...
Regulation of Transpiration by Stomata
The Calvin Benson Cycle
Physiological Control of Respiration
Breathing, a seemingly passive process, is regulated by the respiratory center in the brainstem. This center coordinates the involuntary control of respirations, which means it occurs without conscious effort, ensuring a smooth and uninterrupted pattern.
Regulation of Ventilation
The body maintains ventilation by monitoring levels of carbon dioxide (CO2), oxygen (O2), and hydrogen ion concentration (pH) in the arterial blood. Among these factors, the level of CO2 plays a crucial...

