Effects of Various Environmental Factors on Stomatal Density, Area, and Potential Conductance Index

Stomata, microscopic pores on a leaf flanked with flexible guard cells that open and close the stomatal opening, account for 95% of terrestrial movement of water vapor and carbon essential to the survival of plants. The climate crisis is challenging plants with elevated CO₂, drought, varying soil salinity, varying soil acidity, and increasing temperature. While research has been done on how stomata respond to elevated CO₂ alone, markedly less research has been done on the effect of elevated CO₂ in combination with other environmental factors. Thus, the purpose of this study was to determine the effects of elevated CO₂ in combination with other environmental factors on stomatal density, size, and conductance in radish, barley, tomato, and buckwheat. A controlled experiment with these plants and six conditions (Control, Elevated CO₂, Elevated CO₂ + Salinity, Elevated CO₂ + Acidity, Elevated CO₂ + Temperature, and Elevated CO₂ + Drought) was conducted, and data was collected. The results trend towards a decrease in stomatal density, stomatal area, and potential conductance index (PCI) in the elevated CO₂ conditions compared to the control conditions. Additionally, our results suggest that the other four conditions do not amplify the effect of elevated CO₂ levels alone. Overall, results showed variation in data among the tested plants, suggesting that making generalizations about the impact of CO₂in combination with other environmental factors is risky. Thus, further research on the effects of multiple environmental conditions on stomatal characteristics is warranted to determine the impact on agriculture adaptation and water management strategies.