Assessment of Plant-Based Carbon Bio-Fixation under Elevated CO₂, Nutrient Enrichment, and Temperature Variations

With atmospheric CO₂ concentrations rising due to emissions from industrial point sources such as coal combustion and steel manufacturing, scalable carbon dioxide removal (CDR) strategies are needed. Photosynthetic carbon fixation by plants presents a promising, sustainable approach. While elevated CO₂ (eCO₂) is known to modulate plant traits, the dynamics of carbon conversion under such conditions remain insufficiently understood. The interactive effects of eCO₂, nutrient availability, and temperature are investigated on plant growth and carbon sequestration capacity. The results show that eCO₂ enhances relative growth rate (RGR) and carbon conversion efficiency, with an optimal response observed at 2000 ppm CO₂. Beyond this threshold, at 3000 ppm, photosynthetic gains declined, indicating inhibitory effects of CO₂ oversaturation. Nutrient enrichment under optimal eCO₂ conditions further stimulated biomass production, particularly in shoot tissues, yet do not significantly alter carbon conversion rates, suggesting a plateau in photosynthetic capacity. Elevated temperatures similarly promoted growth and fixation rates up to a thermal optimum, beyond which photosynthetic efficiency declined. These findings demonstrate the potential and limitations of plant-based bio-fixation under future climate scenarios, highlighting its viability as a natural CDR pathway within defined environmental bounds.