Modelling of light driven CO2 concentration gradient and photosynthetic carbon assimilation flux distribution at the chloroplast level

TL;DR

This paper presents a nonlinear diffusion model for CO2 concentration and photosynthetic flux at the chloroplast level, revealing a boundary layer of high CO2 assimilation under intense light, useful for environmental estimations.

Contribution

The paper introduces a detailed nonlinear diffusion model for chloroplast-level CO2 flux, incorporating light-driven reactions and chloroplast geometry, advancing understanding of photosynthetic CO2 assimilation.

Findings

High CO2 assimilation flux boundary layer under intense light

Model enables calculations of CO2 assimilation rates

Detailed analysis of 3D CO2 concentration and flux

Abstract

The steady state of the two-substance model of light driven carbon turnover for the photosynthetic CO2 assimilation rate is presented. The model is based on the nonlinear diffusion equation for a single chloroplast in the elliptical geometry by assuming light driven Ribulose-1,5-bisphosphate (RuBP) regeneration and CO2 assimilation reaction of carboxilation coupled with the photosynthetic sink strength. The detailed analysis of 3 -dimensional CO2 concentration and flux on the chloroplast level is made. It is shown that under intense light irradiation there exists a boundary layer of chloroplasts with a high value of CO2 assimilation flux. The presented simplified model can be used for the calculations and experimental estimations of the CO2 assimilation rate for environmental applications.