Bionic Thermodynamic Model of the Stomatal System of a Plant Leaf: Energy Transformation and CO2 Metabolism

Abstract

The mechanisms of plant leaf gas exchange and their relationship to energy transformation remain insufficiently studied quantitatively, limiting the assessment of CO2 gas exchange processes. In this work, the stomatal system of a plant leaf is analyzed as a micro-, macro-, or nanoscale thermodynamic system, applying modeling based on bionic principles. An idealized thermodynamic cycle is constructed, allowing for the assessment of the conversion of thermal energy into mechanical work. The theoretical upper limit of the thermal efficiency coefficient is estimated at ηt ≈ 0.003, and the mechanical energy flux, at a temperature difference of approximately 1 °C between the leaf and the ambient temperature, reaches up to 0.6 W/m2, i.e., about 0.3% of the solar radiation flux absorbed by the leaf. The results obtained show that even with low efficiency, this energy transformation is sufficient to influence the intensity of gas exchange. Based on the model, the plant’s CO2 sorption potential, depending on canopy area, was also estimated. It is concluded that the stomatal system of a plant leaf can be interpreted as a theoretical bionic energy transformation model, suitable for the analysis of CO2 exchange processes and the development of bionic micro-, macro-, or nanoscale systems.