Ancín and colleagues studied how plants respond to increased CO2 levels combined with drought or heat stress. Examining data from 120 studies on 42 plant species, they found plants still showed increased photosynthesis under high CO2, even with added stress. The research looked at photosynthesis rates, water use, and changes in key plant proteins. Understanding these plant responses is crucial for predicting how crops will fare under future climate conditions.
The team compiled data from numerous experiments on plant responses to elevated CO2 and stress. They used statistical techniques to combine results across studies and test for significant effects. Plant responses were measured at different growth stages (vegetative, heading, flowering, and grain filling) and compared across plant types (non-woody plants, trees, nitrogen-fixing plants, and grasses). The analysis included key measures like photosynthesis rates, water use efficiency, and changes in important plant proteins.
They found that photosynthesis increased by 24% under elevated CO2 alone, and 38% with added stress. Plants reduced water loss by closing leaf pores, but still took in more CO2. The key photosynthesis enzyme Rubisco decreased, but plants compensated with higher activation. These responses varied among plant types, with trees showing the strongest photosynthesis boost. Grasses showed different responses at various growth stages, with CO2 effects most pronounced during reproductive phases.
Previous studies had unclear results on how stress affects plant CO2 responses. This study provides strong evidence that stress does not negate CO2 benefits for plants. Results suggest that even under stressful conditions, plants may still benefit from rising CO2 levels. However, responses vary among plant types and growth stages, highlighting the need for further research on specific crop responses to future climate scenarios.
Ancín, M., Gámez, A.L., Jauregui, I., Galmes, J., Sharwood, R.E., Erice, G., Ainsworth, E.A., Tissue, D.T., Sanz-Sáez, A. and Aranjuelo, I., 2024. Does the response of Rubisco and photosynthesis to elevated [CO2] change with unfavourable environmental conditions?. Journal of Experimental Botany, https://doi.org/10.1093/jxb/erae379
