Adaptive responses to elevated CO₂ in fruit species with different phloem loading mechanisms

Area of Science:

• Plant Physiology
• Agricultural Science
• Environmental Science

Background:

• Phloem loading mechanisms (apoplastic vs. symplastic) may influence plant adaptation to elevated CO₂.
• Strawberry and tomato utilize different phloem loading strategies but both respond positively to increased CO₂.
• Understanding these adaptations is crucial for optimizing crop yields in a changing climate.

Purpose of the Study:

• To investigate the morphological and physiological adaptations of strawberry and tomato to long-term CO₂ enrichment.
• To determine how different phloem loading mechanisms affect yield responses to elevated CO₂.
• To assess the impact of increased CO₂ on plant growth, photosynthesis, and carbon allocation in these crops.

Main Methods:

• Long-term exposure of strawberry (Fragaria × ananassa) and tomato (Solanum lycopersicum) to ambient (400 ppm) and elevated (800 ppm) CO₂ for three months.
• Comprehensive phenotyping, gas exchange analysis, and ¹³C labeling combined with isotope ratio mass spectrometry.
• Evaluation of growth, yield, photosynthesis, and carbon allocation parameters.

Main Results:

• CO₂ enrichment significantly enhanced growth and reproductive development in both species, leading to higher yields.
• Elevated CO₂ increased carbon assimilation in strawberry but not in tomato, which was limited by Rubisco's carboxylation efficiency.
• Both species prioritized fruit development, with carbon allocation remaining similar across CO₂ treatments despite increased assimilation in strawberry.

Conclusions:

• Both strawberry and tomato crops are expected to benefit from future increases in atmospheric CO₂ levels.
• The study supports the use of CO₂ enrichment in greenhouse cultivation for enhanced crop productivity.
• Crop adaptation to elevated CO₂ is primarily driven by species-specific responses rather than the phloem loading mechanism itself.