Simulated Analysis of Influence of Changes in H+-ATPase Activity and Membrane CO2 Conductance on Parameters of Photosynthetic Assimilation in Leaves

Abstract

Photosynthesis is an important process in plants which influences their development and productivity. Many factors can control the efficiency of photosynthesis, including CO2 conductance of leaf mesophyll, which affects the CO2 availability for Rubisco. It is known that electrical stress signals can decrease this conductance, and the response is probably caused by inactivation of H+-ATPase in the plasma membrane. In the current work, we analyzed the influence of both CO2 conductance in the plasma membrane, and chloroplast envelopes and H+-ATPase activity on photosynthetic CO2 assimilation, using a two-dimensional mathematical model of photosynthesis in leaves. The model included a description of assimilation on the basis of the Farquhar–von Caemmerer–Berry model, ion transport through the plasma membrane, diffusion of CO2 in the apoplast, and transport of CO2 through the plasma membrane and chloroplast envelope. The model showed that the photosynthetic CO2 assimilation rate was mainly dependent on the plasma membrane and chloroplast envelope conductance; direct influence of the H+-ATPase activity (through changes in pH and CO2/HCO3− concentration ratio) on this rate was weak. In contrast, both changes in CO2 conductance of the plasma membrane and chloroplast envelopes and changes in the H+-ATPase activity influenced spatial heterogeneity of the CO2 assimilation on the leaf surface in the simulated two-dimensional system. These effects were also observed under simultaneous changes in the CO2 conductance of the plasma membrane and H+-ATPase activity. Qualitatively similar influence of changes in the CO2 conductance of the plasma membrane and chloroplast envelopes, and changes in the H+-ATPase activity on photosynthesis were shown for two different densities of stomata in the simulated leaf; however, lowering the density of stomata decreased the assimilation rate and increased the heterogeneity of assimilation. The results of the model analysis clarify the potential influence of H+-ATPase inactivation on photosynthesis, and can be the basis for development of new methods for remote sensing of the influence of electrical signals.

Development of Modified Farquhar–von Caemmerer–Berry Model Describing Photodamage of Photosynthetic Electron Transport in C3 Plants under Different Temperatures

“…This regeneration was taken as a function of the potential rate of the linear electron flow through the ETC under the specific intensity of actinic light (J, µmol•m −2 •s −1 ). In accordance with a series of works [31,32,36], we did not include the limitation of photosynthetic CO2 assimilation by the rate of triose transport because it was difficultly distinguished from the RuBP carboxylation/oxygenation limitation [36]. Thus, Equations ( 1) and (2) were used for the description of photosynthetic CO2 assimilation (Ahv): Thus, Equations (1) and (2) were used for the description of photosynthetic CO 2 assimilation (A hv ): W = min W j , W c (1)…”

Hyperpolarization electrical signals induced by local action of moderate heating influence photosynthetic light reactions in wheat plants

“…In accordance with Galléet al ( 2013), decreasing the CO 2 mesophyll conductance can be caused by pH-dependent changes in aquaporin conductance because they can transfer CO 2 . The alternative mechanism can be based on pH-dependent shifts between CO 2 and HCO 3 - (Sukhov, 2016) because HCO 3 is weakly transferred across biological membranes (Tholen and Zhu, 2011); however, our recent model-based analysis showed that these shifts weakly influence the photosynthetic CO 2 assimilation (Sukhova et al, 2022). The inactivation of the photosynthetic dark reactions suppresses the photosynthetic light reactions (Sukhov, 2016).…”

“…It means that this K + decrease can compensate increasing the total proton concentration (free and buffer-bonded protons) and, thereby, decreases concentration of free protons in the apoplast (and increases its pH). Mechanism of the apoplastic K + decrease can be based on the hyperpolarization of the plasma membrane that stimulates the potassium ion influx through increasing the K + motive force and activating potential-dependent inwardly rectifying K + channels ( Sukhova et al., 2022 ).…”

“…Partially, it can be caused by increasing amplitude of HESs ( Figure 14B ); however, this increase is not significant. Our previous model-based analysis ( Sukhova et al., 2022 ) showed that influence of ESs-induced decreasing the CO 2 mesophyll conductance on photosynthesis is stimulated with lowering quantity of open stomata. Considering closure of stomata under drought ( Zivcak et al., 2013 ), we suppose that this closure can be potential mechanism of increasing magnitude of HESs-induced photosynthetic changes under the moderate soil drought.…”

Spectral composition of LED light differentially affects biomass, photosynthesis, nutrient profile, and foliar nitrate accumulation of lettuce grown under various replacement methods of nutrient solution

“…However, specific mechanisms of this influence are not fully clear and can be the basis for development of new methods (Sukhova et al, 2022). Researchers suggest that the early vascular plants respond to both RL and BL and actively regulate stomatal aperture.…”