Can leaf net photosynthesis acclimate to rising and more variable temperatures?

Area of Science:

• Plant physiology
• Climate change biology
• Photosynthetic research

Background:

• Future climates predict higher and more variable leaf temperatures (Tl).
• Plant carbon balance is sensitive to short-term temperature fluctuations and long-term acclimation.
• Photosynthesis and respiration rates are temperature-dependent.

Purpose of the Study:

• To quantify how increased mean and variability in growth temperature affect leaf carbon gain.
• To assess the buffering capacity of photosynthetic acclimation against rising and variable leaf temperatures.
• To determine the extent to which acclimation can maintain net CO2 assimilation rates (Anet).

Main Methods:

• Combined probabilistic descriptions of short- and long-term temperature changes with Anet response data.
• Utilized data from 75 genera and 111 species (C3 and C4 plants).
• Calculated the probability distribution of Anet under various thermal regimes.

Main Results:

• Increased Tl variability decreases mean Anet and increases its variability.
• The impact of higher mean Tl on Anet is species- and initial Tl-dependent.
• Photosynthetic acclimation maintained Anet at >80% of maximum under most simulated thermal conditions.

Conclusions:

• Photosynthetic acclimation plays a crucial role in mitigating negative impacts of rising leaf temperatures.
• While acclimation offers significant buffering, increased temperature variability poses a challenge to plant carbon gain.
• Understanding thermal acclimation is vital for predicting plant responses to future climate change.