ORIGINAL ARTICLE

Photosynthetic Adaptations and Metabolic Responses of Medicinal Plants to Elevated CO₂ and Abiotic Stress

Photosynthesis is a fundamental process influenced by plant species and environmental factors, particularly elevated atmospheric CO₂ and temperature. Increased CO₂ enhances photosynthetic rates while reducing stomatal conductance, promoting plant growth. However, abiotic stresses such as heat and drought significantly impair photosynthesis, as observed in medicinal plants. Canopy temperature regulation and transpiration rates shift under high temperatures, affecting water-use efficiency and physiological adaptations. Membrane stability, critical under stress conditions, is compromised by lipid peroxidation and oxidative damage, leading to cellular dysfunction. Antioxidant defense mechanisms, including enzymatic responses, mitigate reactive oxygen species (ROS) accumulation under abiotic stress. Elevated CO₂ enhances photosynthesis and growth in several medicinal plants, such as Ocimum sanctum and Gynostemma pentaphyllum, though stressors like drought and heat influence metabolic pathways, secondary metabolite accumulation, and overall yield. Notably, medicinal plant quality is altered by climate variables, affecting chemical composition and therapeutic efficacy. While some species benefit from climate-induced changes in metabolite production, others exhibit declines in potency. The findings highlight the complex interplay between photosynthesis, stress adaptation, and secondary metabolite biosynthesis under changing environmental conditions, emphasizing the need for further research on climate-resilient medicinal plant cultivation.