Physiological Responses of Plants to Elevated Carbon Dioxide and Drought Stress

Plants exposed to elevated atmospheric CO2 typically exhibit enhanced rates of carboxylation and biomass accumulation, owing to increased substrate availability for photosynthesis and reduced photorespiration. Under concurrent drought, these elevations in carbon gain often coincide with reductions in stomatal conductance, leading to improved intrinsic water-use efficiency and conservation of soil water. Biochemical adjustments include modulation of non-structural carbohydrate pools, reinforcement of antioxidative defence systems and osmotic adjustment through compatible solute accumulation. Hydraulic acclimation is mediated by changes in root-to-shoot signalling, often via abscisic acid, and by alterations in aquaporin expression that govern water transport. Anatomical responses such as reduced stomatal density and modified mesophyll structure further optimise gas exchange under water deficit. Together, these integrated responses influence plant fitness, yield stability and carbon sequestration potential in a drier, CO2-rich world.

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Physiological Responses of Plants to Elevated Carbon Dioxide and Drought Stress publication trend

The graph below shows the total number of articles in physiological responses of plants to elevated carbon dioxide and drought stress across all publications each year (not limited to Nature Index journals).

Technical terms

Stomatal conductance: rate of gas exchange through leaf stomata, influencing CO2 assimilation and transpiration.

Water-use efficiency: ratio of carbon fixed by photosynthesis to water lost via transpiration.

Mesophyll conductance: ease of CO2 diffusion from intercellular air spaces to chloroplasts.

Photosystem II: chloroplast complex that initiates light-driven water splitting and electron transport.

Non-structural carbohydrates: soluble sugars and starches used for energy, osmotic balance and stress defence.

Reactive oxygen species (ROS): highly reactive molecules derived from oxygen that can damage cellular components if not scavenged.

References

1. Greater Biomass Production Under Elevated CO2 Is Attributed to Physiological Optimality, Trade-Offs in Nutrient Allocation, and Oxidative Defense in Drought-Stressed Mulberry. Antioxidants (2025).
2. Elevated [CO2] negatively impacts C4 photosynthesis under heat and water stress without penalizing biomass. Journal of Experimental Botany (2023).
3. ABA-mediated regulation of leaf and root hydraulic conductance in tomato grown at elevated CO2 is associated with altered gene expression of aquaporins. Horticulture Research (2019).