Light exposure reshapes photosynthetic thermal tolerance curves, with idiosyncratic responses across 36 species.

Light exposure significantly alters photosynthetic thermal tolerance curves, with 36 tropical species showing diverse responses, including changes in thermal thresholds and decline width.

• Why it matters: Understanding how light influences thermal tolerance is crucial because natural heat stress occurs under illumination, yet many assessments are based on dark conditions, risking inaccurate vulnerability estimates.
• What they did: The study measured full temperature response curves of PSII efficiency (Fv/Fm) in 36 tropical species under sub-saturating light, revealing variable shifts in thermal thresholds and broadening of decline ranges.
• The result: Findings suggest that incorporating ecologically relevant light conditions into thermal tolerance tests can improve predictions of plant responses to climate warming, acknowledging high interspecies variability.