A three-dimensional stomatal CO2 exchange model including gaseous phase and leaf mesophyll separated by irregular...

Area of Science:

• Plant Physiology
• Biophysical Modeling
• Photosynthesis Research

Background:

• Understanding carbon dioxide (CO2) diffusion into plant leaves is crucial for photosynthesis.
• Stomatal geometry and internal leaf structure influence CO2 transport.
• Biochemical processes within mesophyll cells act as CO2 sinks.

Purpose of the Study:

• To develop a 3D model simulating CO2 diffusion from air into leaf mesophyll cells.
• To investigate the impact of stomatal geometry on CO2 flux and concentration.
• To analyze the effects of CO2 solubility and environmental factors (temperature, pH) on CO2 uptake.

Main Methods:

• Construction of a three-dimensional model with distinct air and mesophyll phases.
• Incorporation of a biochemical photosynthesis model for CO2 sinks in Scots pine.
• Simulation of CO2 diffusion under varying stomatal geometries and boundary conditions.

Main Results:

• Net CO2 flux is sensitive to the intercellular-air-space (IAS)-mesophyll interface size, especially at low mesophyll transport coefficients.
• An optimal balance exists between mesophyll volume and the air-mesophyll interface for CO2 uptake.
• CO2 solubility, influenced by temperature and pH, significantly affects CO2 flux, with higher pH leading to increased temperature optima and mesophyll CO2 concentrations.

Conclusions:

• Stomatal and internal leaf structures play a key role in regulating CO2 availability for photosynthesis.
• Environmental factors like temperature and pH can modulate CO2 diffusion dynamics and photosynthetic capacity.
• The model provides insights into optimizing leaf design for enhanced carbon assimilation.